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Sample records for reduction study prepared

  1. Report Tunneling Cost Reduction Study prepared for Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    1999-07-16

    Fermi National Accelerator Laboratories has a need to review the costs of constructing the very long tunnels which would be required for housing the equipment for the proposed Very Large Hadron Collider (VLHC) project. Current tunneling costs are high, and the identification of potential means of significantly reducing them, and thereby helping to keep overall project costs within an acceptable budget, has assumed great importance. Fermilab has contracted with The Robbins Company to provide an up-to-date appraisal of tunneling technology, and to review the potential for substantially improving currently the state-of-practice performance and construction costs in particular. The Robbins Company was chosen for this task because of its long and successful experience in hard rock mechanical tunnel boring. In the past 40 years, Robbins has manufactured over 250 tunneling machines, the vast majority for hard rock applications. In addition to also supplying back-up equipment, Robbins has recently established a division dedicated to the manufacture of continuous conveying equipment for the efficient support of tunneling operations. The study extends beyond the tunnel boring machine (TBM) itself, and into the critical area of the logistics of the support of the machine as it advances, including manpower. It is restricted to proven methods using conventional technology, and its potential for incremental but meaningful improvement, rather than examining exotic and undeveloped means of rock excavation that have been proposed from time to time by the technical community. This is the first phase of what is expected to be a number of studies in increasing depth of technical detail, and as such has been restricted to the issues connected with the initial 34 kilometer circumference booster tunnel, and not the proposed 500 kilometer circumference tunnel housing the VLHC itself. The booster tunnel is entirely sited within low to medium strength limestone and dolomite formations

  2. Reduction mechanism of Ni2+ into Ni nanoparticles prepared from different precursors: Magnetic studies

    Indian Academy of Sciences (India)

    R S Ningthoujam; N S Gajbhiye; Sachil Sharma

    2009-03-01

    The reduction mechanism of Ni2+ into Ni particles using different precursors such as NiCl2 solution, NiO powder and Ni[(NH3)6]Cl2 complex has been established. Different particle sizes can be designed from these precursors. The smallest crystallite size (12 nm) can be obtained from Ni[(NH3)6]Cl2 complex in the presence of the stabilizing ligand (oleic acid). The field-cooled (FC) and zero-field-cooled (ZFC) magnetization of Ni particles obtained from Ni[(NH3)6]Cl2 complex in the temperature range 5–300 K established the ferromagnetic interaction up to 300 K. The magnetization values at three different temperatures 5, 70 and 300 K are 50.2, 49.5 and 45.5 Oe respectively at 3 × 104 Oe applied field and such values are less than that of the bulk value. The Curie temperature (c) decreases slightly with the decrease of particle size. This study will provide guidance in the preparation of metal nanoparticles from different precursors.

  3. Preparation of copper oxide modified boron-doped diamond electrodes and its preliminary study for CO2 reduction

    Science.gov (United States)

    Yetri, N. Y.; Ivandini, T. A.; Gunlazuardi, J.

    2017-04-01

    Preparation of boron-doped diamond (BDD) modified with Cu2O (Cu2O-BDD) electrodes was conducted to study the electrochemical reduction of CO2. The electrodes were prepared by electrochemical reduction using a solution containing 1mM Cu(CH3COO)2 and 0.1 M CH3COONa (1:1) at pH 5.7 for 60 s. The electrodeposition of Cu2O at BDD surface was performed by chronoamperometry technique at -0.4 V (vs Ag/AgCl). SEM-EDS and XPS were utilized to characterize the electrodes. At Cu2O-BDD electrodes, cyclic voltammetry of dissolved CO2 in 0.1 M NaCl solution exhibited a reduction peak at around -1.3 V (vs Ag/AgCl), indicated the possibility for application in electrochemical reduction of CO2.

  4. Studies on the reduction of aortic calcification by alkali citrates in an ex vivo tissue preparation in the rat.

    Science.gov (United States)

    Schick, C H; Schwille, P O

    1993-08-01

    The effect of orally administered alkali citrates on the calcification of arterial vessel was studied in the rat. Freshly dissected aortic segments were placed in Millipore diffusion chambers and grafted intraperitoneally. Within 21 days calcification of the media had developed. Under treatment with 2.1 mmol citrate per animal and day a significant decrease in histologically detectable calcification areas occurred, as assessed by greatest thickness and longitudinal expansion. This effect was more pronounced with potassium citrate and potassium sodium citrate, and less marked with sodium citrate. The calcium and phosphorus content of aortic tissue remained unchanged, but magnesium increased significantly. The spheroid particles deposited in the media were characterized in more detail by electron microscopy and elemental microanalysis, X-ray diffraction, and determination of the molar calcium-phosphorus ratio. The combined data suggest that in the model selected for studying biocalcification not mature hydroxyapatite but some precursor of this substance is deposited, and that in animals receiving alkali citrate treatment deposition of amorphous calcium phosphate is likely. It is concluded that in the ex vivo aortic wall preparation oral alkali citrates a) bring about a reduction in calcification areas in the media layer, b) impair the maturation of hydroxyapatite and its deposition in the arterial tissue; c) promote the accumulation of magnesium. Whether these results are of significance for the calcification of arteries in situ and treatment regimens is unknown.

  5. Comparative study to evaluate the accuracy of polyether occlusal bite registration material and occlusal registration wax as a guide for occlusal reduction during tooth preparation

    Directory of Open Access Journals (Sweden)

    Niranjan Joshi

    2013-01-01

    Objective: The objective of this study was to compare and evaluate the reliability of the most commonly used occlusal registration wax that with polyether bite registration material as a guide for occlusal reduction required during tooth preparations. Materials and Methods: For the purpose of this study, 25 abutment teeth requiring tooth preparation for fixed prosthesis were selected and tooth preparations carried out. Modeling wax strips of specific dimensions were placed onto the cast of prepared tooth, which was mounted on maximum intercuspation on the articulator and the articulator was closed. The thickness of the wax registration was measured at three zones namely two functional cusps and central fossa. Similar measurements were made using the polyether bite registration material and prosthesis at the same zones. The data was tabulated and was subjected to statistical analysis using anova test and Tukey honestly significant difference test. Results: The differences in thickness between wax record and prosthesis by 0.1346 mm, whereas the difference between polyether and prosthesis was 0.02 mm with a P value of 0.042, which is statistically significant. This means that the wax record was 8.25% larger than the prosthesis while polyether was just 1.27% larger than the prosthesis. Conclusion: The clinical significance of the above analysis is that Ramitec polyether bite registration material is most suitable material when compared with commonly used modeling wax during the tooth preparation.

  6. Studies on plutonium-zirconium co-precipitation and carbothermal reduction in the internal gelation process for nitride fuel preparation

    Science.gov (United States)

    Hedberg, Marcus; Ekberg, Christian

    2016-10-01

    Sol-gel based techniques are one way to lower the handling of highly radioactive powders when producing transuranium-containing fuel. In this work inert matrix (Zr0.6,Pu0.4)N fuel has been produced by internal gelation followed by carbothermal reduction. No co-gelation was observed during internal gelation and a two phase material could be detected by scanning electron microscopy in the nitrided microspheres. Sintering has been performed in both Ar and N2. X-ray diffraction revealed that sintering in N2 produced a solid solution, while sintering in Ar did not. The final metal composition in the microspheres was determined by ICP-MS to be about 41% Pu and 59% Zr. Vegard's law was applied to estimate the nitride purity in the solid solution pellet to be Zr0.6Pu0.4N0.87C0.13 making the final material more of a carbonitride than a pure nitride.

  7. Study of Eu{sup 3+} → Eu{sup 2+} reduction in BaAl{sub 2}O{sub 4}:Eu prepared in different gas atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Rezende, Marcos V. dos S., E-mail: mvsrezende@gmail.com [Departamento de Física, Universidade Federal de Sergipe, Campus Universitário, 49100-000 Itabaiana-SE (Brazil); Valerio, Mário E.G. [Departamento de Física, Universidade Federal de Sergipe, Campus Universitário, 49100-000 São Cristovão-SE (Brazil); Jackson, Robert A. [School of Physical and Geographical Sciences, Keele University, Keele, Staffordshire ST5 5BG (United Kingdom)

    2015-01-15

    Highlights: • The effect of different gas atmospheres on the Eu reduction process was studied. • The Eu reduction was monitored analyzing XANES region at the Eu L{sub III}-edge. • Hydrogen reducing agent are the most appropriate gas for Eu{sup 2+} stabilization. • Only a part of the Eu ions can be stabilized in the divalent state. • A model of Eu reduction process is proposed. - Abstract: The effect of different gas atmospheres such as H{sub 2}(g), synthetic air, carbon monoxide (CO) and nitrogen (N{sub 2}) on the Eu{sup 3+} → Eu{sup 2+} reduction process during the synthesis of Eu-doped BaAl{sub 2}O{sub 4} was studied using synchrotron radiation. The Eu{sup 3+} → Eu{sup 2+} reduction was monitored analyzing XANES region when the sample are excited at the Eu L{sub III}-edge. The results show that the hydrogen reducing agent are the most appropriate gas for Eu{sup 2+} stabilization in BaAl{sub 2}O{sub 4} and that only a part of the Eu ions can be stabilized in the divalent state. A model of Eu reduction process, based on the incorporation of charge compensation defects, is proposed.

  8. Heliostat cost reduction study.

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Scott A.; Lumia, Ronald. (University of New Mexico, Albuquerque, NM); Davenport, Roger (Science Applications International Corporation, San Diego, CA); Thomas, Robert C. (Advanced Thermal Systems, Centennial, CO); Gorman, David (Advanced Thermal Systems, Larkspur, CO); Kolb, Gregory J.; Donnelly, Matthew W.

    2007-06-01

    Power towers are capable of producing solar-generated electricity and hydrogen on a large scale. Heliostats are the most important cost element of a solar power tower plant. Since they constitute {approx} 50% of the capital cost of the plant it is important to reduce heliostat cost as much as possible to improve the economic performance of power towers. In this study we evaluate current heliostat technology and estimate a price of $126/m{sup 2} given year-2006 materials and labor costs for a deployment of {approx}600 MW of power towers per year. This 2006 price yields electricity at $0.067/kWh and hydrogen at $3.20/kg. We propose research and development that should ultimately lead to a price as low as $90/m{sup 2}, which equates to $0.056/kWh and $2.75/kg H{sup 2}. Approximately 30 heliostat and manufacturing experts from the United States, Europe, and Australia contributed to the content of this report during two separate workshops conducted at the National Solar Thermal Test Facility.

  9. Characterization and study of reduction and sulfurization processing in phase transition from molybdenum oxide (MoO{sub 2}) to molybdenum disulfide (MoS{sub 2}) chalcogenide semiconductor nanoparticles prepared by one-stage chemical reduction method

    Energy Technology Data Exchange (ETDEWEB)

    Shomalian, K.; Bagheri-Mohagheghi, M.M.; Ardyanian, M. [Damghan University, School of Physics, Damghan (Iran, Islamic Republic of)

    2017-01-15

    In this research, molybdenum disulfide (MoS{sub 2}) nanoparticles were prepared by chemical reduction method using MoO{sub 3} and thiourea as a precursor. The physical properties of the synthesized MoO{sub 2}-MoS{sub 2} nanoparticles annealed at different temperatures of 200, 300, 750 C have been investigated, before and after exposure to sulfur vapor. The nanostructure of nanoparticles has been characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM) analyses and UV-Vis spectrophotometer. The X-ray diffraction analysis showed the formation of MoS{sub 2} single phase at annealing temperature of 750 C in the presence of sulfur vapor. The Raman spectrum of the nanoparticles revealed that the formation of MoS{sub 2} at 750 C after annealing in sulfur vapor. The values of band gap were obtained in the range of 3.64-3.17 eV and 3.47-1.95 eV for MoS{sub 2} nanoparticles before and after exposure to sulfur vapor, respectively. According to SEM images, the grain size decreases with increasing annealing temperature up to 750 C. Also, nanoplate-nanoparticles of MoS{sub 2} are formed at annealing temperature of 200-750 C. The TEM images of MoS{sub 2} nanoparticles at T{sub a} = 750 C confirm that the nanoparticles have a homogeneous distribution with a hexagonal structure. The FTIR spectra of the MoS{sub 2} nanoparticles showed the peaks at about 467 cm {sup -1} belong to the characteristic bands of Mo-S. (orig.)

  10. Characterization and study of reduction and sulfurization processing in phase transition from molybdenum oxide (MoO2) to molybdenum disulfide (MoS2) chalcogenide semiconductor nanoparticles prepared by one-stage chemical reduction method

    Science.gov (United States)

    Shomalian, K.; Bagheri-Mohagheghi, M.-M.; Ardyanian, M.

    2017-01-01

    In this research, molybdenum disulfide (MoS2) nanoparticles were prepared by chemical reduction method using MoO3 and thiourea as a precursor. The physical properties of the synthesized MoO2-MoS2 nanoparticles annealed at different temperatures of 200, 300, 750 °C have been investigated, before and after exposure to sulfur vapor. The nanostructure of nanoparticles has been characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM) analyses and UV-Vis spectrophotometer. The X-ray diffraction analysis showed the formation of MoS2 single phase at annealing temperature of 750 °C in the presence of sulfur vapor. The Raman spectrum of the nanoparticles revealed that the formation of MoS2 at 750 °C after annealing in sulfur vapor. The values of band gap were obtained in the range of 3.64-3.17 eV and 3.47-1.95 eV for MoS2 nanoparticles before and after exposure to sulfur vapor, respectively. According to SEM images, the grain size decreases with increasing annealing temperature up to 750 °C. Also, nanoplate-nanoparticles of MoS2 are formed at annealing temperature of 200-750 °C. The TEM images of MoS2 nanoparticles at T a = 750 °C confirm that the nanoparticles have a homogeneous distribution with a hexagonal structure. The FTIR spectra of the MoS2 nanoparticles showed the peaks at about 467 cm-1 belong to the characteristic bands of Mo-S.

  11. Preparation and Electrochemical Properties of the Pd-modified Cu Electrode for Nitrate Reduction in Water

    Institute of Scientific and Technical Information of China (English)

    Ying WANG; Jiu Hui QU; Hui Juan LIU

    2006-01-01

    The Pd-modified Cu (Pd/Cu) electrodes for nitrate reduction were prepared using electro-deposition method at different potentials. Compared with other different electrodes so far studied in our work (Cu, Sn/Cu and Pd/Ti electrode) using cyclic voltammetry method, Pd/Cu electrode showed the highest electrocatalytic capacity of nitrate reduction. It was found that at more negative electrode potential the smaller Pd particles formed on the Cu electrode, which was beneficial to the nitrate reduction. With increasing deposition amount of Pd, the capacity of nitrate reduction increased. Too rich Pd, however, has a negative influence on the capacity of nitrate reduction. In our study, the maximum nitrate reduction current was 2.07 mA/cm2, when electrodeposition potential of Pd was -0.3 V and deposition amount was 0.9 C.

  12. A reduction approach to prepare ZnSe nanocrystallites

    Institute of Scientific and Technical Information of China (English)

    JIANG Hai-qing; CHE Jun; LI Zhi-min; YAO Xi

    2006-01-01

    ZnSe nanocrystallites powders were successfully prepared by reduction method with H2SeO4 or H2SeO3 as selenium source and Zn(Ac)2·H2O as zinc source. The reaction mechanism was also discussed through XRD and DTA/TG analysis. In the process,ZnSeO4·H2O or ZnSeO3·H2O crystallites precipitated in organic solvent was prepared at first. Then the crystallites were reduced with carbon monoxide atmosphere. The XRD analysis reveals that the structure of ZnSe phase is sphalerite (cubic ZnS). The XPS results show that the atomic ratio of Se to Zn is 1-1 approximately. The TEM shows that the size of ZnSe crystallite is 30-50 nm. This method of synthesis of ZnSe nanocrystallites has the potential application in the preparation of optical composite thin films from sol-gel process.

  13. Amorphous TM1−xBx alloy particles prepared by chemical reduction (invited)

    DEFF Research Database (Denmark)

    Linderoth, Søren; Mørup, Steen

    1991-01-01

    Amorphous transition-metal boron (TM-B) alloy particles can be prepared by chemical reduction of TM ions by borohydride in aqueous solutions. ln the last few years systematic studies of the parameters which control the composition, and, in turn, many of the properties of the alloy particles, have...... been performed and are reviewed in the present paper. The most important preparation parameters which influence the composition are the concentration of the borohydride solution and the pH of the TM salt solution. By controlling these parameters it is possible to prepare amorphous alloy samples...

  14. Preparation and Microstructure of Bauxite-Based Sialon by Reduction Nitridation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Haijun; LIU Zhanjie; ZHONG Xiangchong

    2004-01-01

    The phase compostition and microstructure of Sialon prepared from Chinese bauxite have been studied.The use of Si powder is more effective than that of activated carbon for reduction-nitridation.For bauxite specimens with 40~50% Si addition,more than 90% of Sialon may be obtained when nitrided at 1450~1500℃;the main crystalline phase is O'-Sialon(Z=0.2).

  15. Preparation for teacher collaboration in inclusive classrooms - stress reduction for special education students via acceptance and commitment training: A controlled study.

    Science.gov (United States)

    Pülschen, Simone; Pülschen, Dietrich

    2015-01-01

    The education system in Germany is beginning to witness a sea change, lately, owing to the country's ratification of the United Nation's Convention on the Rights of Persons with Disabilities. The enactment is aiming at making provision for special education teachers to share the same teaching platform and institution with other teachers for teaching children from all backgrounds, irrespective of their needs. While promoting the benefits of collaborative teaching, this provision would also effectively establish role demarcation among teachers. However, the level of participation and adaptiveness displayed by individual teachers would play a major role in determining the success or failure of the intended collaborative framework. Collaboration also becomes challenging due to the level of stress involved in the teaching profession. The fact that only 65 % of teachers in Germany reach retirement age while still in service, primarily due to psychiatric illness, has posed questions on adopting the collaborative framework for teachers from diverse backgrounds. In other words, it can be stated that the process of collaborating with teachers from different professional backgrounds and with varying levels of skills will potentially lead to further stress. The stress-related psychological states, developed through the collaborative processes, might affect the biological stress-response systems of the participating teachers. With stress-response contributing directly to the pathogenesis of stress-related diseases and disorders in the long term, it would be important to contain the ripple effect of collaborative framework that the enactment intends to establish between SEN (special educational needs) teachers and others. In addition to impacting the long-term health of teachers, the collaborative framework is also suggestive of having similar effects on students studying special education (SEN students). A study was conducted to examine the stress levels associated with the

  16. Aluminothermic Reduction of K2ZrF6 for Preparation of Al-Zr Master Alloy

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    This paper summarizes a process for the preparation of Al-5%Zr master alloy by the reduction of K2ZrF6 with aluminium. The reduction in grain size of aluminium by addition of known quantity of master alloy is also studied.

  17. Preparation of Metallic Iron Powder from Pyrite Cinder by Carbothermic Reduction and Magnetic Separation

    Directory of Open Access Journals (Sweden)

    Hongming Long

    2016-04-01

    Full Text Available The reduction and magnetic separation procedure of pyrite cinder in the presence of a borax additive was performed for the preparation of reduced powder. The effects of borax dosage, reduction temperature, reduction time and grinding fineness were investigated. The results show that when pyrite cinder briquettes with 5% borax were pre-oxidized at 1050 °C for 10 min, and reduced at 1050 °C for 80 min, with the grinding fineness (<0.44 mm passing 81%, the iron recovery was 91.71% and the iron grade of the magnetic concentrate was 92.98%. In addition, the microstructures of the products were analyzed by optical microscope, scanning electron microscope (SEM, and mineralography, and the products were also studied by the X-ray powder diffraction technique (XRD to investigate the mechanism; the results show that the borax additive was approved as a good additive to improve the separation of iron and gangue.

  18. Preparing Students for Studying Abroad

    Science.gov (United States)

    Goldoni, Federica

    2015-01-01

    This study is situated in the fields of language education, study abroad (SA) and intercultural communication. The interest in SA is increasing on the part of students, administrators, educators, and business companies for the learning opportunities that it offers. However, SA students are not always prepared to maximize their learning…

  19. Lake Nasser evaporation reduction study

    Directory of Open Access Journals (Sweden)

    Hala M.I. Ebaid

    2010-10-01

    Full Text Available This study aims to evaluate the reduction of evaporation of Lake Nasser’s water caused by disconnecting (fully or partially some of its secondary channels (khors. This evaluation integrates remote sensing, Geographic Information System (GIS techniques, aerodynamic principles, and Landsat7 ETM+ images. Three main procedures were carried out in this study; the first derived the surface temperature from Landsat thermal band; the second derived evaporation depth and approximate evaporation volume for the entire lake, and quantified evaporation loss to the secondary channels’ level over one month (March by applied aerodynamic principles on surface temperature of the raster data; the third procedure applied GIS suitability analysis to determine which of these secondary channels (khors should be disconnected. The results showed evaporation depth ranging from 2.73 mm/day at the middle of the lake to 9.58 mm/day at the edge. The evaporated water-loss value throughout the entire lake was about 0.86 billion m3/month (March. The analysis suggests that it is possible to save an approximate total evaporation volume loss of 19.7 million m3/month (March, and thus 2.4 billion m3/year, by disconnecting two khors with approximate construction heights of 8 m and 15 m. In conclusion, remote sensing and GIS are useful for applications in remote locations where field-based information is not readily available and thus recommended for decision makers remotely planning in water conservation and management.

  20. Preparation, anti-biofouling and drag-reduction properties of a biomimetic shark skin surface

    Directory of Open Access Journals (Sweden)

    Xia Pu

    2016-04-01

    Full Text Available Shark skin surfaces show non-smoothness characteristics due to the presence of a riblet structure. In this study, biomimetic shark skin was prepared by using the polydimethylsiloxane (PDMS-embedded elastomeric stamping (PEES method. Scanning electron microscopy (SEM was used to examine the surface microstructure and fine structure of shark skin and biomimetic shark skin. To analyse the hydrophobic mechanism of the shark skin surface microstructure, the effect of biomimetic shark skin surface microstructure on surface wettability was evaluated by recording water contact angle. Additionally, protein adhesion experiments and anti-algae adhesion performance testing experiments were used to investigate and evaluate the anti-biofouling properties of the surface microstructure of biomimetic shark skin. The recorded values of the water contact angle of differently microstructured surfaces revealed that specific microstructures have certain effects on surface wettability. The anti-biofouling properties of the biomimetic shark skin surface with microstructures were superior to a smooth surface using the same polymers as substrates. Moreover, the air layer fixed on the surface of the biomimetic shark skin was found to play a key role in their antibiont adhesion property. An experiment into drag reduction was also conducted. Based on the experimental results, the microstructured surface of the prepared biomimetic shark skin played a significant role in reducing drag. The maximum of drag reduction rate is 12.5%, which is higher than the corresponding maximum drag reduction rate of membrane material with a smooth surface.

  1. Study on the preparation of Pt nanocapsules

    Science.gov (United States)

    Zhang, Yi-fan; Ji, Zhen; Chen, Ke; Liu, Bo-wen; Jia, Cheng-chang; Yang, Shan-wu

    2017-01-01

    Ag@Pt core-shell nanoparticles (Ag@Pt NPs) were prepared by a co-reduction method. Pt nanocapsules with diameters of less than 10 nm were obtained by an electrochemical method. Cyclic voltammetry (CV) scanning was used to cavitate the Ag@Pt NPs, and the morphology, structure, and cavitation conditions were studied. The results indicate that the effective cavitation conditions to obtain Pt nanoparticles from Ag@Pt NPs are a scanning voltage of 0 to 0.8 V and continuous CV scanning over 2 h. This cavitation method is also applicable for the syntheses of Ir, Ru, and Ru-Pt nanocapsules.

  2. Preparation and characterization of noble metal nanocolloids by silk fibroin in situ reduction

    Institute of Scientific and Technical Information of China (English)

    CHEN; Wenxing(陈文兴); WU; Wen(吴雯); CHEN; Haixiang(陈海相); SHEN; Zhiquan(沈之荃)

    2003-01-01

    Noble metal nanocolloids are prepared from their precursors by in situ reduction of a silk fibroin solution at room temperature without any reducing agent. The mechanism, the effects of pH and the molar ratio of the reactants on the reduction reaction are studied by UV-Vis spectroscopy. The structure of the colloids is characterized by FT-IR, TEM and AFM. According to the TEM images, the gold-silk fibroin colloid is a nanostructured bioconjugate with novel core-shell, while the silver-silk fibroin colloid tends to be congregated as clusters having more than ten nanoparticles of silver-silk fibroin. The gold colloid is highly dispersed and stable while the silver colloid is less dispersed and stable than the gold colloid.

  3. Intervention of gender friendly land preparation technologies for drudgery reduction of hill farm women.

    Science.gov (United States)

    Kishtwaria, Jatinder; Rana, Aruna

    2012-01-01

    Inventory of all agricultural tasks depicted land preparation by women farmers as one of the most drudgery prone task with high energy cost, thereby, making it amenable to ergonomic interventions in terms of improved technologies (clod breaker, improved plough/'danella') to relieve women from high energy demands, time spent and associated drudgery. The study was conducted in two hill states of India viz. Himachal Pradesh (35 villages and 900 representative samples) and Uttrakhand (10 villages and 900 representative samples). Experimental data were conducted on representative sub sample of 60 hill farm women of both the states to assess physiological workload and musculo-skeletal problems both while working with traditional tools along with improved tools by employing selected parameters viz. physical fitness level, physiological parameters etc. The results showed that heart rate values were more than acceptable limits for task performed with the traditional tools as compared with improved tools. Significant reduction in the heart rate was observed while working with improved tools. Analysis of MSDs showed that the postural stress and severity of pain in various body parts was reduced by adopting new technology. Hence, the use of improved land preparation tools is recommended over the existing ones for drudgery reduction.

  4. Reduction of Enterococcus faecalis in curved root canals after various sizes and tapers of canal preparation

    Directory of Open Access Journals (Sweden)

    Amir Abbas Moshari

    2015-01-01

    Full Text Available Aims: The aim of this study was to evaluate the reduction of Enterococcus faecalis in curved root canals after various sizes and tapers of the canal preparation. Materials and Methods: Mandibular first molars (n = 103 with curved mesiobuccal canals were divided into one control (n = 5 and 7 experimental (n = 14 groups, were inoculated with E. faecalis (ATTC 29212 and prepared with the following RaCe files (FKG Dentaire as master apical file: Groups: 25.04, 25.06, 30.04, 30.06, 35.04, 35.06 and 40.06. All the experimental groups were irrigated with 2 mL of 1% sodium hypochlorite during instrumentation and finally rinsed with 17% ethylenediaminetetraacetic acid (EDTA (2 mL followed by 5.25% NaOCl (2 mL and sterile distilled water. Colony counting was performed after incubation. Statistical Analysis Used: Resulting data were analyzed using one-way ANOVA and Tukey′s post-hoc test, (P < 0.05. Results and Conclusions: All the experimental groups showed significant bacterial reduction (P < 0.001. Although the greater the size/taper or both led to more decreased amount of bacteria, differences between the groups with the identical size and different tapers, and among the groups with the same taper and different sizes were not significant. Based on this study, 25.04 along with using 2 mL of 1% NaOCl during instrumentation, and using 17% EDTA and 5.25% NaOCl as final rinse successively after the termination of preparation, can effectively reduce intra-canal bacteria and preserve root structure.

  5. Preparation of niobium carbide powder by electrochemical reduction in molten salt

    Energy Technology Data Exchange (ETDEWEB)

    Song, Qiushi [School of Materials Science and Metallurgy, Northeastern University, Shenyang 110819 (China); Xu, Qian, E-mail: qianxu201@mail.neu.edu.cn [School of Materials Science and Metallurgy, Northeastern University, Shenyang 110819 (China); School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Meng, Jingchun; Lou, Taiping; Ning, Zhiqiang [School of Materials Science and Metallurgy, Northeastern University, Shenyang 110819 (China); Qi, Yang [College of Science, Northeastern University, Shenyang 110819 (China); Yu, Kai [School of Materials Science and Metallurgy, Northeastern University, Shenyang 110819 (China)

    2015-10-25

    The niobium carbide powder was prepared via electrochemical reduction of the mixture of Nb{sub 2}O{sub 5} and carbon in molten CaCl{sub 2}–NaCl. The reaction pathway from the sintered precursor to the final product has been investigated. The effect of the working temperature on the reduction of the Nb{sub 2}O{sub 5}/C composite precursor was considered. The role of carbon during the electrochemical reduction of the composite pellet was discussed. The samples were analysed by XRD and SEM. The results indicated that the NbC powder was approximately 200 nm after the reduction. Nb{sub 2}O{sub 5} was gradually reduced to Nb, and NbC was subsequently obtained by the reaction of carbon with Nb metal. In addition, Nb{sub 2}O{sub 5} could spontaneously react with CaO in the melt to form a serious of calcium niobates. The participation of carbon was available for the efficiency of electro-reduction of Nb{sub 2}O{sub 5}. - Graphical abstract: Niobium carbide powder was electrochemically prepared in molten salt, and the reduction pathway was illustrated schematically. - Highlights: • NbC powder was prepared electrochemically in molten salt. • The working temperature was lower than that of carbothermic reduction. • The reduction pathway was discussed compared to direct electro-deoxidation of Nb{sub 2}O{sub 5}.

  6. Polyphosphoester-Camptothecin Prodrug with Reduction-Response Prepared via Michael Addition Polymerization and Click Reaction.

    Science.gov (United States)

    Du, Xueqiong; Sun, Yue; Zhang, Mingzu; He, Jinlin; Ni, Peihong

    2017-04-26

    Polyphosphoesters (PPEs), as potential candidates for biocompatible and biodegradable polymers, play an important role in material science. Various synthetic methods have been employed in the preparation of PPEs such as polycondensation, polyaddition, ring-opening polymerization, and olefin metathesis polymerization. In this study, a series of linear PPEs has been prepared via one-step Michael addition polymerization. Subsequently, camptothecin (CPT) derivatives containing disulfide bonds and azido groups were linked onto the side chain of the PPE through Cu(I)-catalyzed azidealkyne cyclo-addition "click" chemistry to yield a reduction-responsive polymeric prodrug P(EAEP-PPA)-g-ss-CPT. The chemical structures were characterized by nuclear magnetic resonance spectroscopy, gel permeation chromatography, Fourier transform infrared, ultraviolet-visible spectrophotometer, and high performance liquid chromatograph analyses, respectively. The amphiphilic prodrug could self-assemble into micelles in aqueous solution. The average particle size and morphology of the prodrug micelles were measured by dynamic light scattering and transmission electron microscopy, respectively. The results of size change under different conditions indicate that the micelles possess a favorable stability in physiological conditions and can be degraded in reductive medium. Moreover, the studies of in vitro drug release behavior confirm the reduction-responsive degradation of the prodrug micelles. A methyl thiazolyl tetrazolium assay verifies the good biocompatibility of P(EAEP-PPA) not only for normal cells, but also for tumor cells. The results of cytotoxicity and the intracellular uptake about prodrug micelles further demonstrate that the prodrug micelles can efficiently release CPT into 4T1 or HepG2 cells to inhibit the cell proliferation. All these results show that the polyphosphoester-based prodrug can be used for triggered drug delivery system in cancer treatment.

  7. Case study: Natural bodybuilding contest preparation.

    Science.gov (United States)

    Kistler, Brandon M; Fitschen, Peter J; Ranadive, Sushant M; Fernhall, Bo; Wilund, Kenneth R

    2014-12-01

    The purpose of this study was to document the physiological changes that occur in a natural bodybuilder during prolonged contest preparation for a proqualifying contest. During the 26-week preparation, the athlete undertook a calorically restrictive diet with 2 days of elevated carbohydrate intake per week, increased cardiovascular (CV) training, and attempted to maintain resistance-training load. The athlete was weighed twice a week and body composition was measured monthly by DXA. At baseline and every 2 weeks following CV structure and function was measured using a combination of ultrasound, applanation tonometry, and heart rate variability (HRV). Cardiorespiratory performance was measured by VO(2)peak at baseline, 13 weeks, and 26 weeks. Body weight (88.6 to 73.3 Kg, R(2) = .99) and percent body fat (17.5 to 7.4%) were reduced during preparation. CV measurements including blood pressure (128/61 to 113/54 mmHg), brachial pulse wave velocity (7.9 to 5.8m/s), and measures of wave reflection all improved. Indexed cardiac output was reduced (2.5 to 1.8L/m(2)) primarily due to a reduction in resting heart rate (71 to 44 bpm), and despite an increase in ejection faction (57.9 to 63.9%). Assessment of HRV found a shift in the ratio of low to high frequency (209.2 to 30.9%). Absolute VO2 was minimally reduced despite weight loss resulting in an increase in relative VO2 (41.9 to 47.7 ml/Kg). In general, this prolonged contest preparation technique helped the athlete to improve body composition and resulted in positive CV changes, suggesting that this method of contest preparation appears to be effective in natural male bodybuilders.

  8. [Bioequivalence studies of pharmaceutical preparations].

    Science.gov (United States)

    Vetchý, D; Frýbortová, K; Rabisková, M; Danecková, H

    2007-01-01

    Bioequivalence studies are very important for the development of a pharmaceutical preparation in the pharmaceutical industry. Their rationale is the monitoring of pharmacokinetic and pharmacodynamic parameters after the administration of tested drugs. The target of such study is to evaluate the therapeutic compatibility of tested drugs (pharmaceutical equivalents or pharmaceutical alternatives). The importance of bioequivalence studies is increasing also due to the large growth of the production and consumption of generic products. Generic products represent approximately 50 % of the whole consumption in many European countries and USA. The search output of bioequivalence study is together with the pharmaceutical quality data of medical product one of the main part of the registration file submitted to a national regulatory authorities. The registration of generic products does not demand complicated and expensive clinical study contrary to original product. The comparison of the original and the generic product via bioequivalence study is suggested as sufficient. The aim of this article is to provide to a medical public a summary about the types of bioequivalence studies, their range, rules of their practise and let them gain their own attitude to this question.

  9. Food Mass Reduction Trade Study

    Science.gov (United States)

    Perchonok, Michele H.; Stoklosa, Adam M.

    2009-01-01

    Future long duration manned space flights beyond low earth orbit will require the food system to remain safe, acceptable, and nutritious while efficiently balancing appropriate vehicle resources such as mass, volume, power, water, and crewtime. Often, this presents a challenge since maintaining the quality of the food system can result in a higher mass and volume. The Orion vehicle is significantly smaller than the Shuttle vehicle and the International Space Station and the mass and volume available for food is limited. Therefore, the food team has been challenged to reduce the mass of the packaged food from 1.82 kg per person per day to 1.14 kg per person per day. Past work has concentrated on how to reduce the mass of the packaging which contributes to about 15% of the total mass of the packaged food system. Designers have also focused on integrating and optimizing the Orion galley equipment as a system to reduce mass. To date, there has not been a significant effort to determine how to reduce the food itself. The objective of this project is to determine how the mass and volume of the packaged food can be reduced while maintaining caloric and hydration requirements. The following tasks are the key elements to this project: (1) Conduct further analysis of the ISS Standard Menu to determine moisture, protein, carbohydrate, and fat levels. (2) Conduct trade studies to determine how to bring the mass of the food system down. Trade studies may include removing the water of the total food system and/or increasing the fat content. (3) Determine the preferred method for delivery of the new food (e.g. bars, or beverages) and the degree of replacement. (4) Determine whether there are commercially available products that meet the requirements. By the end of this study, an estimate of the mass and volume savings will be provided to the Constellation Program. In addition, if new technologies need to be developed to achieve the mass savings, the technologies, timeline, and

  10. Preparation of niobium nanoparticles by sodiothermic reduction of Nb_2O_5 in molten salts

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Niobium nanoparticles with high purity were prepared by a sodiothermic reduction process using Nb2O5 as the raw material, LiCl, NaCl, KCl and CaCl2 as the diluents and sodium as the reducing reagent. The effects of the different molten salt systems, CaCl2 content, reaction time, excessive sodium and reaction temperature on the characteristics of the obtained niobium powder were discussed. The as-prepared niobium nanoparticles under the optimum experimental conditions were obtained by sodiothermic reduction ...

  11. Preparation of graphene sponge by vapor phase reduction for oil and organic solvent removal

    Science.gov (United States)

    Wu, Ruihan; Yu, Baowei; Jin, Xinyan; Liu, Xiaoyang; Bai, Yitong; Chen, Lingyun; Ming, Zhu; Yang, Hua; Yang, Sheng-Tao; Luo, Jianbin

    2016-10-01

    Due to the porous structure and hydrophobicity, graphene sponge has huge adsorption capacity for oils and organic solvents. In this study, we reported that graphene sponge could be prepared by vapor phase reduction (denoted as VPRGS) for oil and organic solvent removal. Graphene oxide was lyophilized and reduced by steamy hydrazine hydrate to produce VPRGS. VPRGS had huge capacity for oils and organic solvents (72–224 g g‑1). In particular, the adsorption capacity for crude oil reached 165 g g‑1, suggesting that VPRGS could be applied in oil leakage remediation. VPRGS could treat pollutants both in pure liquid form and in the simulated sea water, where the hydrophobic nature of VPRGS allowed the floating of VPRGS on simulated sea water. VPRGS could be easily regenerated without obvious capacity loss up to 9 cycles. The implications to the applications of VPRGS in oil/water separation and water remediation are discussed.

  12. Preparation of Phenolic Resin/Silver Nanocomposites via in-situ Reduction

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Resol type phenolic resin/silver nanocomposite was prepared by in-situ reduction method, in which the curing of phenolic resin and the formation of silver nano-particles took place simultaneously. The silver ions were reduced completely to silver nanoparticles, which were dispersed homogeneously in the resin matrix with narrow size distribution.

  13. Three-dimensional assemblies of graphene prepared by a novel chemical reduction-induced self-assembly method

    KAUST Repository

    Zhang, Lianbin

    2012-01-01

    In this study, three-dimensional (3D) graphene assemblies are prepared from graphene oxide (GO) by a facile in situ reduction-assembly method, using a novel, low-cost, and environment-friendly reducing medium which is a combination of oxalic acid (OA) and sodium iodide (NaI). It is demonstrated that the combination of a reducing acid, OA, and NaI is indispensable for effective reduction of GO in the current study and this unique combination (1) allows for tunable control over the volume of the thus-prepared graphene assemblies and (2) enables 3D graphene assemblies to be prepared from the GO suspension with a wide range of concentrations (0.1 to 4.5 mg mL-1). To the best of our knowledge, the GO concentration of 0.1 mg mL-1 is the lowest GO concentration ever reported for preparation of 3D graphene assemblies. The thus-prepared 3D graphene assemblies exhibit low density, highly porous structures, and electrically conducting properties. As a proof of concept, we show that by infiltrating a responsive polymer of polydimethylsiloxane (PDMS) into the as-resulted 3D conducting network of graphene, a conducting composite is obtained, which can be used as a sensing device for differentiating organic solvents with different polarity. © 2012 The Royal Society of Chemistry.

  14. Low-Cost Radon Reduction Pilot Study

    Energy Technology Data Exchange (ETDEWEB)

    Rose, William B. [Partnership for Advanced Residential Retrofit, Champaign, IL (United States); Francisco, Paul W. [Partnership for Advanced Residential Retrofit, Champaign, IL (United States); Merrin, Zachary [Partnership for Advanced Residential Retrofit, Champaign, IL (United States)

    2015-09-01

    The aim of the research was to conduct a primary scoping study on the impact of air sealing between the foundation and the living space on radon transport reduction across the foundation-living space floor assembly. Fifteen homes in the Champaign, Illinois area participated in the study. These homes were instrumented for hourly continuous radon measurements and simultaneous temperature and humidity the foundation was improved. However, this improved isolation did not lead to significant reductions in radon concentration in the living space. Other factors such as outdoor temperature were shown to have an impact on radon concentration.

  15. Simple preparation of Pd-Pt nanoalloy catalysts for methanol-tolerant oxygen reduction

    Science.gov (United States)

    He, Wei; Liu, Juanying; Qiao, Yongjin; Zou, Zhiqing; Zhang, Xiaogang; Akins, Daniel L.; Yang, Hui

    Carbon-supported Pd-Pt bimetallic nanoparticles of different atomic ratios (Pd-Pt/C) have been prepared by a simple procedure involving the complexing of Pd and Pt species with sodium citrate followed by ethylene glycol reduction. As-prepared Pd-Pt alloy nanoparticles evidence a single-phase fcc disordered structure, and the degree of alloying is found to increase with Pd content. Both X-ray diffraction and transmission electron microscopy characterizations indicate that all the Pd-Pt/C catalysts possess a similar mean particle size of ca. 2.8 nm. The highest mass and specific activity of the oxygen reduction reaction (ORR) using the Pd-Pt/C catalysts are found with a Pd:Pt atomic ratio of 1:2. Moreover, all Pd-Pt alloy catalysts exhibit significantly enhanced methanol tolerance during the ORR than the Pt/C catalyst, ensuring a higher ORR performance while diminishing Pt utilization.

  16. Ferrocenyl branched poly (ethylene imine) micelles as reductive templates for the preparation of silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Leize; Zhou Wenbo; Ji Jian, E-mail: jijian@zju.edu.c [Zhejiang University, Department of Polymer Science, Key Laboratory of Macromolecule Synthesis and Functionalization of Minister of Education (China)

    2010-08-15

    Polymeric micelles with a branched poly (ethylene imine) shell and a reductive ferrocene core were prepared via self-assembly of ferrocene modified branched poly (ethylene imine) (BPEI-Fc). The well-controlled polymeric micelles with a reductive core were used as templates to prepare core-shell-structured silver nanoparticles (AgNPs) in aqueous solution. The as-prepared nanoparticles were characterized by UV-Vis spectrophotometer, transmission electron microscope (TEM), selected-area electron diffraction (SAED), thermogravimetry analyzer (TGA), and dynamic light scattering (DLS). The AgNPs of 39 {+-} 9 nm with a 39-nm BPEI layer were obtained. It is demonstrated that ferrocene, which is a neutral, chemically stable, and nontoxic molecule, plays a dual role as the hydrophobe and as the electron donating group. Moreover, the formation of these particles was monitored in situ by UV-Vis spectrophotometer. It is found that the growth of AgNPs through reductive templates is much slower than that reduced by NaBH{sub 4}. Meanwhile, the size distribution of AgNPs becomes narrower during the reaction. BPEI-covered AgNPs (Ag-BPEI) are stable up to 3 months and carry amino groups, which can further be bioconjugated. These core-shell-structured nanoparticles may enable them to be used for wide applications in aqueous solution.

  17. Ferrocenyl branched poly (ethylene imine) micelles as reductive templates for the preparation of silver nanoparticles

    Science.gov (United States)

    Zhu, Lei-ze; Zhou, Wen-bo; Ji, Jian

    2010-08-01

    Polymeric micelles with a branched poly (ethylene imine) shell and a reductive ferrocene core were prepared via self-assembly of ferrocene modified branched poly (ethylene imine) (BPEI-Fc). The well-controlled polymeric micelles with a reductive core were used as templates to prepare core-shell-structured silver nanoparticles (AgNPs) in aqueous solution. The as-prepared nanoparticles were characterized by UV-Vis spectrophotometer, transmission electron microscope (TEM), selected-area electron diffraction (SAED), thermogravimetry analyzer (TGA), and dynamic light scattering (DLS). The AgNPs of 39 ± 9 nm with a 39-nm BPEI layer were obtained. It is demonstrated that ferrocene, which is a neutral, chemically stable, and nontoxic molecule, plays a dual role as the hydrophobe and as the electron donating group. Moreover, the formation of these particles was monitored in situ by UV-Vis spectrophotometer. It is found that the growth of AgNPs through reductive templates is much slower than that reduced by NaBH4. Meanwhile, the size distribution of AgNPs becomes narrower during the reaction. BPEI-covered AgNPs (Ag@BPEI) are stable up to 3 months and carry amino groups, which can further be bioconjugated. These core-shell-structured nanoparticles may enable them to be used for wide applications in aqueous solution.

  18. Preparation of Ferrotitanium Alloy from Ilmenite by Electrochemical Reduction in Chloride Molten Salts

    Science.gov (United States)

    Qi, Can-can; Hua, Yi-xin; Chen, Kong-hao; Jie, Ya-fei; Zhou, Zhong-ren; Ru, Juan-jian; Xiong, Li; Gong, Kai

    2016-02-01

    Ferrotitanium alloy is prepared by electrochemical reduction from ilmenite in LiCl-KCl and LiCl-KCl-CaCl2 molten salts, respectively. The products prepared are observed by x-ray diffraction (XRD). It is shown that Fe2Ti can be prepared from ilmenite in LiCl-KCl molten salt at 1073 K with a cell voltage of 3.2 V. Ilmenite can be electrochemically reduced to FeTi in LiCl-KCl-CaCl2 molten salt under the same condition. It is indicated that CaCl2 can promote the reaction and is favors the deoxidization of the FeTiO3.

  19. Carbon Dioxide Reduction Technology Trade Study

    Science.gov (United States)

    Jeng, Frank F.; Anderson, Molly S.; Abney, Morgan B.

    2011-01-01

    For long-term human missions, a closed-loop atmosphere revitalization system (ARS) is essential to minimize consumables. A carbon dioxide (CO2) reduction technology is used to reclaim oxygen (O2) from metabolic CO2 and is vital to reduce the delivery mass of metabolic O2. A key step in closing the loop for ARS will include a proper CO2 reduction subsystem that is reliable and with low equivalent system mass (ESM). Sabatier and Bosch CO2 reduction are two traditional CO2 reduction subsystems (CRS). Although a Sabatier CRS has been delivered to International Space Station (ISS) and is an important step toward closing the ISS ARS loop, it recovers only 50% of the available O2 in CO2. A Bosch CRS is able to reclaim all O2 in CO2. However, due to continuous carbon deposition on the catalyst surface, the penalties of replacing spent catalysts and reactors and crew time in a Bosch CRS are significant. Recently, technologies have been developed for recovering hydrogen (H2) from Sabatier-product methane (CH4). These include methane pyrolysis using a microwave plasma, catalytic thermal pyrolysis of CH4 and thermal pyrolysis of CH4. Further, development in Sabatier reactor designs based on microchannel and microlith technology could open up opportunities in reducing system mass and enhancing system control. Improvements in Bosch CRS conversion have also been reported. In addition, co-electrolysis of steam and CO2 is a new technology that integrates oxygen generation and CO2 reduction functions in a single system. A co-electrolysis unit followed by either a Sabatier or a carbon formation reactor based on Bosch chemistry could improve the overall competitiveness of an integrated O2 generation and CO2 reduction subsystem. This study evaluates all these CO2 reduction technologies, conducts water mass balances for required external supply of water for 1-, 5- and 10-yr missions, evaluates mass, volume, power, cooling and resupply requirements of various technologies. A system

  20. Magnesium Production by Silicothermic Reduction of Dolime in Pre-prepared Dolomite Pellets

    Science.gov (United States)

    Fu, Da-Xue; Zhang, Ting-An; Guan, Lu-Kui; Dou, Zhi-He; Wen, Ming

    2016-12-01

    A novel process has been proposed for magnesium production, in which powder materials including dolomite, ferrosilicon, fluorite and binder are mixed to produce pellets. Kinetics of the silicothermic reduction using the pre-prepared dolomite pellets was investigated by a non-isothermal, flowing argon-protected gravimetric technique at a temperature range from 1323 K to 1673 K. The results suggest that the process is controlled by a chemical reaction, with the second-order chemical reaction model providing the best representation of the process. The apparent activation energy was determined to be 280 kJ/mol. Calcium silicide (was found in the pellet after calcinations. The silicothermic process in the pre-prepared dolomite pellets is possibly a solid-liquid reaction since calcium silicide transformed into liquid alloy, which reduced diffusion resistance of silicon during the reduction process. The gas-film mass transfer may have some effect on the reduction kinetics but is not the major rate-limiting step.

  1. Preparation of carbon supported Pt-P catalysts and its electrocatalytic performance for oxygen reduction

    Energy Technology Data Exchange (ETDEWEB)

    Ma Juan [Institute of Chemical Power Sources, Soochow University, Suzhou 215006 (China); Tang Yawen; Yang Gaixiu; Chen Yu [College of Chemistry and Material Science, Nanjing Normal University, Nanjing 210097 (China); Zhou Qun [Institute of Chemical Power Sources, Soochow University, Suzhou 215006 (China); Lu Tianhong [College of Chemistry and Material Science, Nanjing Normal University, Nanjing 210097 (China); Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Zheng Junwei, E-mail: jwzheng@suda.edu.cn [Institute of Chemical Power Sources, Soochow University, Suzhou 215006 (China)

    2011-05-15

    The carbon supported PtP (PtP/C) catalysts were synthesized from Pt(NO{sub 3}){sub 2} and phosphorus yellow at the room temperature. The content of P in the PtP/C catalysts prepared with this method is high and the average size of the PtP particles is decreased with increasing the content of P. The electrocatalytic performances of the PtP/C catalysts prepared with this method for the oxygen reduction reaction (ORR) are better than that of the commercial Pt/C catalyst. The promotion action of P for enhancing the electrocatalytic performance of the PtP/C catalyst for ORR is mainly due to that Pt and P form the alloy and then the electron density of Pt is decreased.

  2. Preparation of ferromagnetic binary alloy fine fibers byorganic gel-thermal reduction process

    Institute of Scientific and Technical Information of China (English)

    SHEN Xiang-qian; CAO Kai; ZHOU Jian-xin

    2006-01-01

    Ferromagnetic metal fibers with a high aspect ratio (length/diameter) are attractive for use as high performance electromagnetic interference shielding materials. Ferromagnetic binary alloy fine fibers of iron-nickel, iron-cobalt and cobalt-nickel were prepared by the organic gel-thermal reduction process from the raw materials of critic acid and metal salts. These alloy fibers synthesized were featured with a diameter of about 1 μm and a length as long as 1 m. The structure, thermal decomposition process and morphologies of the gel precursors and fibers derived from thermal reduction of the gel precursors were characterized by FTIR, XRD, TG/DSC and SEM. The gel spinnability largely depends on the molecular structure of metal- carboxylates formed during the gel formation. The gel consisting of linear-type structural molecules shows good spinnability.

  3. Preparation of ferromagnetic metal fine fibers by organic gel-thermal reduction process

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The organic gel-thermal reduction process was used for the preparation of ferromagnetic metal Ni, Co and Fe fine fibers from the raw materials of citric acid, lactic acid and metal salts. The structure, thermal decomposition process and morphologies of the gel precursors and fibers derived from thermal reduction of these gel precursors were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermo-gravimetric/differential scanning calorimetry and scanning electron microscopy. The results show that spinnability of gel largely depends on molecular structure of metal-carboxylate complex that is a linear-type structure formed in the gel. As a result, the gels exhibit a good spinnability. Metal Ni, Co and Fe fine fibers are featured with diameters of around 1 urn and a high aspect ratio up to 1×106.

  4. Preparation of DyFe2 and TbFe2 by Reduction-Diffusion Process

    Institute of Scientific and Technical Information of China (English)

    Guangsi GUO; Guangtai WANG; Zhitong SUI

    2004-01-01

    The pure intermetallic compounds (Tb1-xDyx)Fe2 are super-magnetostriction materials, which were produced from DyFe2and TbFe2 in this paper. The thermodynamic possibility and kinetic feasible conditions for DyFe2 and TbFe2 preparation by reduction-diffusion in Ca-Dy2O3-Fe and Ca-Tb4O7-Fe systems were analyzed and the products of DyFe2 and TbFe2 were confirmed by XRD. The contracting core model was applied to describe the reduction-diffusion process in which the diffusion is a rate-controlled step. The apparent activation energies of DyFe2 and TbFe2 processes are 45 and 39 k J/mol respectively.

  5. Preparation, toxicity and mutagenicity of 1-methyl-2-nitrosoimidazole. A toxic 2-nitroimidazole reduction product.

    Science.gov (United States)

    Noss, M B; Panicucci, R; McClelland, R A; Rauth, A M

    1988-07-01

    1-Methyl-2-nitrosoimidazole (INO), the 2-electron reduction product of 1-methyl-2-nitroimidazole (INO2), was prepared by electrochemical reduction of INO2 to 2-hydroxylamino-1-methyl-imidazole (INHOH), followed by back oxidation with iodine. Although stable in crystalline form, INO reacted in water, phosphate-buffered saline, and mammalian cell growth medium. Half-lives for decay were determined by UV-visible spectroscopy. INO was found to be highly toxic towards Chinese hamster ovary (CHO) cells, concentrations of 10-60 microM producing significant cytotoxicity. The rate of INO decay was found to be increased in the presence of CHO cells. INO was also toxic and mutagenic towards Salmonella typhimurium TA-100. When compared on a molar basis to the parent nitro compound INO2, and the 4- and 6-electron reduction products INHOH and 2-amino-1-methylimidazole (INH2), INO was by far (two orders of magnitude) the most toxic under aerobic conditions. These results suggest that the nitroso reduction product of 2-nitroimidazoles may be the reduced species responsible for hypoxic cell selective toxicity of 2-nitroimidazoles.

  6. Preparation of fine nickel powders via reduction of nickel hydrazine complex precursors

    Institute of Scientific and Technical Information of China (English)

    HUANG Guo-yong; XU Sheng-ming; XU Gang; LI Lin-yan; ZHANG Li-feng

    2009-01-01

    Fine nickel(Ni) powders with controllable particle sizes were synthesized via the reduction of nickel hydrazine complex precursors of pure [Ni(N2H4)2]Cl2 and a mixture of [Ni(N2H4)2]Cl2 and [Ni(N2H4)3]Cl2 in aqueous solution. The mechanism of the formation of metallic Ni powders experiences the reduction of nickel hydroxide by hydrazine released from the ligand exchange reaction between nickel hydrazine complex and NaOH. In comparison with the method of preparing Ni powders from nickel salts, the method of making Ni powders via the reduction of nickel hydrazine complex precursors shows the advantages of using half dosage of hydrazine for complete reduction of nickel ions in solution, and the obtained Ni particles show less agglomeration and better dispersibility. Moreover, the average particle size of nickel powders can be controlled from 180 to 260 nm by adjusting the reaction molar ratio and concentration.

  7. Preparation of Ti by direct electrochemical reduction of solid TiO2 and its reaction mechanism

    Institute of Scientific and Technical Information of China (English)

    NIE Xin-miao; DONG Ling-yan; BAI Chen-guang; CHEN Deng-fu; QIU Gui-bao

    2006-01-01

    An electrochemical method for the direct reduction of solid TiO2 was introduced,in which the oxygen is ionized,dissolved in the molten salt and discharged at the anode,leaving pure titanium at the cathode. Titanium was prepared from TiO2 via molten salt electrolysis,and experimental process was studied in detail. The reductive products of TiO2 were analyzed through XRD,SEM,XPS and so on. The results indicate that titanium with high purity is obtained by the electrochemical reduction. Through thermogravimetric analysis of molten CaCl2,it is shown that the dehydration of CaCl2 has to be strictly controlled to eliminate hydrolysis. The cyclic voltammetry studies on the TiO2 cathode electrochemical system show that the reduction of TiO2 is conducted step by step,from exterior to interior and from high-valence to low-valence. The conclusions were also confirmed by study on thermodynamics analysis. The current efficiency can be improved by loading different voltages in different stages.

  8. A preliminary analysis of the reduction of chemotherapy waste in the treatment of cancer with centralization of drug preparation

    Directory of Open Access Journals (Sweden)

    Adriano Hyeda

    2015-08-01

    Full Text Available SummaryIntroduction:chemotherapy is essential to treat most types of cancer. Often, there is chemotherapy waste in the preparation of drugs prescribed to the patient. Leftover doses result in toxic waste production.Objective:the aim of the study was to analyze chemotherapy waste reduction at a centralized drug preparation unit.Methods:the study was cross-sectional, observational and descriptive, conducted between 2010 and 2012. The data were obtained from chemotherapy prescriptions made by oncologists linked to a health insurance plan in Curitiba, capital of the state of Paraná, in southern Brazil. Dose and the cost of chemotherapy waste were calculated in each application, considering the dose prescribed by the doctor and the drug dosages available for sale. The variables were then calculated considering a hypothetical centralized drug preparation unit.Results:there were 176 patients with a cancer diagnosis, 106 of which underwent treatment with intravenous chemotherapy. There were 1,284 applications for intravenous anticancer medications. There was a total of 63,824mg in chemotherapy waste, the cost of which was BRL 448,397.00. The average cost of chemotherapy waste per patient was BRL 4,607.00. In the centralized model, there was 971.80mg of chemotherapy waste, costing BRL 13,991.64. The average cost of chemotherapy waste per patient was BRL 132.00.Conclusion:the use of centralized drug preparation units may be a strategy to reduce chemotherapy waste.

  9. Preparation of Aluminium Oxynitride by Carbothermal Reduction of Aluminium Oxide in a Flowing N2 Atmosphere

    Institute of Scientific and Technical Information of China (English)

    LIYa-wei; YUANRun-zhang; 等

    1996-01-01

    Carbothermal reduction of alumina into aluminium oxynitride(AlON) spinel in a flowing nitrogen atmosphere was studied.The effects of Al2O3/C ratio temperature,soaking time,heating rate molding pressure of samples,and nitrogen flow rate on reactions were investigated.Then the stability of AlON was elucidated and AlON wa confirmed as an intermediate compound in reduction of alumina.

  10. Magnetic and electrical properties of oxygen stabilized nickel nanofibers prepared by the borohydride reduction method

    Energy Technology Data Exchange (ETDEWEB)

    Srinivas, V. [Department of Physics and Meteorology, Indian Institute of Technology, Kharagpur West Bengal 721 302 India (India)], E-mail: veeturi@phy.iitkgp.ernet.in; Barik, S.K.; Bodo, Bhaskarjyoti [Department of Physics and Meteorology, Indian Institute of Technology, Kharagpur West Bengal 721 302 India (India); Karmakar, Debjani; Chandrasekhar Rao, T.V. [Technical Physics and Prototype Engineering Division, Bhabha Atomic Research Centre, Bombay 400085 India (India)

    2008-03-15

    Fine nickel fibers have been synthesized by chemical reduction of nickel ions in aqueous medium with sodium borohydride. The thermal stability and relevant properties of these fibers, as-prepared as well as air-annealed, have been investigated by structural, magnetic and electrical measurements. As-prepared samples appear to have a novel crystal structure due to the presence of interstitial oxygen. Upon annealing in air, the fcc-Ni phase emerges out initially and develops into a nanocomposite subsequently by retaining its fiber-like structure in nano phase. The as-prepared sample is observed to be weakly magnetic at room temperature, but attains surprisingly high magnetization values at low temperatures. This is attributed to the modified spin structure, presumably due to the presence of interstitial oxygen in the lattice. Development of a weakly ferromagnetic and electrically conducting phase upon annealing in air is attributed to the formation of the fcc-Ni phase. The structural phase transformations corroborate well with magnetic and electrical measurements.

  11. Stable aqueous dispersions of graphene prepared with hexamethylenetetramine as a reductant.

    Science.gov (United States)

    Shen, Xiaoping; Jiang, Lei; Ji, Zhenyuan; Wu, Jili; Zhou, Hu; Zhu, Guoxing

    2011-02-15

    Highly stable graphene aqueous dispersions were achieved by chemical reduction of graphene oxide with an environmentally friendly reagent of hexamethylenetetramine (HMTA). By this method, chemical reduction as well as dispersion of graphene can be carried out in one step without the need of organic stabilizers or pH control. The as-synthesized products were characterized by Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, X-ray diffraction, Raman spectroscopy, atomic force microscopy, scanning and transmission electron microscopy, and thermogravimetry and differential scanning calorimetry. It is revealed that the bulk of the oxygen-containing functional groups were removed from graphene oxide via HMTA reduction, and stable aqueous colloidal dispersions of graphene have a concentration up to ca. 0.65mg/mL. Moreover, it is found that the freshly precipitated graphene nanosheets can be re-dispersed in water with simple ultrasonic treatment. A mechanism for the formation of stable graphene colloidal dispersions is proposed. This simple and green approach should find practical applications in the preparation of graphene-based nanocomposites with a facile and low-cost solution processing technique.

  12. Participatory three dimensional mapping for the preparation of landslide disaster risk reduction program

    Science.gov (United States)

    Kusratmoko, Eko; Wibowo, Adi; Cholid, Sofyan; Pin, Tjiong Giok

    2017-07-01

    This paper presents the results of applications of participatory three dimensional mapping (P3DM) method for fqcilitating the people of Cibanteng' village to compile a landslide disaster risk reduction program. Physical factors, as high rainfall, topography, geology and land use, and coupled with the condition of demographic and social-economic factors, make up the Cibanteng region highly susceptible to landslides. During the years 2013-2014 has happened 2 times landslides which caused economic losses, as a result of damage to homes and farmland. Participatory mapping is one part of the activities of community-based disaster risk reduction (CBDRR)), because of the involvement of local communities is a prerequisite for sustainable disaster risk reduction. In this activity, participatory mapping method are done in two ways, namely participatory two-dimensional mapping (P2DM) with a focus on mapping of disaster areas and participatory three-dimensional mapping (P3DM) with a focus on the entire territory of the village. Based on the results P3DM, the ability of the communities in understanding the village environment spatially well-tested and honed, so as to facilitate the preparation of the CBDRR programs. Furthermore, the P3DM method can be applied to another disaster areas, due to it becomes a medium of effective dialogue between all levels of involved communities.

  13. Oxygen reduction reaction catalyzed by platinum nanonetwork prepared by template free one step synthesis for polymer electrolyte membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Narayanamoorthy, B. [Department of Chemistry, Faculty of Science, Sri Chandrasekharendra Saraswathi Viswa Mahavidyalaya (SCSVMV University), Enathur, Kanchipuram 631 561 (India); Kumar, B.V.V.S. Pavan; Eswaramoorthy, M. [Nanomaterials and Catalysis Lab, Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Bangalore 560 064 (India); Balaji, S., E-mail: prof.balaji13@gmail.com [Department of Chemistry, Faculty of Science, Sri Chandrasekharendra Saraswathi Viswa Mahavidyalaya (SCSVMV University), Enathur, Kanchipuram 631 561 (India)

    2014-07-01

    Highlights: • Supportless Pt nanonetwork (Pt NN) synthesized by novel template free one step method as per our earlier reported procedure. • Electrocatalytic activity of Pt NN studied taking oxygen reduction reaction in acid medium. • Kinetic and thermodynamic parameters were deduced under hydrodynamic conditions. • ORR mechanistic pathway was proposed based on kinetic rate constants. • ADT analysis found enhanced stability (5000 cycles) for Pt NN than Pt NN/VC and reported Pt/C. - Abstract: The reduction reaction of molecular oxygen (ORR) was investigated using supportless Pt nanonetwork (Pt NN) electrocatalyst in sulfuric acid medium. Pt NN was prepared by template free borohydride reduction. The transmission electron microscope images revealed a network like nano-architecture having an average cluster size of 30 nm. The electrochemical characterization of supportless and Vulcan carbon supported Pt NN (Pt NN/VC) was carried out using rotating disc and ring disc electrodes at various temperatures. Kinetic and thermodynamic parameters were estimated under hydrodynamic conditions and compared with Pt NN/VC and reported Pt/C catalysts. The accelerated durability test revealed that supportless Pt NN is quite stable for 5000 potential cycles with 22% reduction in electrochemical surface area (ECSA). While the initial limiting current density has in fact increased by 11.6%, whereas Pt NN/VC suffered nearly 55% loss in ECSA and 13% loss in limiting current density confirming an enhanced stability of supportless Pt NN morphology for ORR compared to conventional Pt/C ORR catalysts in acid medium.

  14. Preparation of Si3N4 Form Diatomite via a Carbothermal Reduction-Nitridation Process

    Science.gov (United States)

    Ma, Bin; Huang, Zhaohui; Mei, Lefu; Fang, Minghao; Liu, Yangai; Wu, Xiaowen; Hu, Xiaozhi

    2016-05-01

    Si3N4 was produced using diatomite and sucrose as silicon and carbon sources, respectively. The effect of the C/SiO2 molar ratio, heating temperature and soaking time on the morphology and phase compositions of the final products was investigated by scanning electron microscopy, x-ray diffraction analysis and energy dispersive spectroscopy. The phase equilibrium relationships of the system at different heating temperatures were also investigated based on the thermodynamic analysis. The results indicate that the phase compositions depended on the C/SiO2 molar ratio, heating temperature and soaking time. Fabrication of Si3N4 from the precursor via carbothermal reduction nitridation was achieved at 1550°C for 1-8 h using a C/SiO2 molar ratio of 3.0. The as-prepared Si3N4 contained a low amount of Fe3Si (<1 wt.%).

  15. Hydrogenation of Styrene Oxide to 2-Phenylethanol over Nanocrystalline Ni Prepared by Ethylene Glycol Reduction Method

    Directory of Open Access Journals (Sweden)

    Sunil K. Kanojiya

    2014-01-01

    Full Text Available Nanocrystalline nickel prepared by glycol reduction method and characterized by XRD and magnetic measurements has been used as a catalyst for hydrogenation of styrene oxide to 2-phenylethanol. Effect of process variables such as particle size of the catalyst, temperature, and pressure have been optimized to achieve a maximum conversion of 98% of styrene oxide with 99% selectivity towards 2-phenylethanol. The structure of the transition state has been computed employing density functional theory and using Gaussian 09 suite. The enthalpy of reaction (ΔH and activation energy (Ea are calculated to be 85.3 kcal·mol−1 and 123.03 kcal·mol−1, respectively. A tentative mechanism for the reaction is proposed according to which atomized hydrogen and styrene oxide react together over the catalyst surface to produce 2-phenylethanol.

  16. Preparation of Ultrafine Cobalt Powder by Chemical Reduction in Aqueous Solution

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Nanocrystalline cobalt powders have been prepared from aqueous solution by reducing their corresponding metal salts under suitable conditions. The experimental conditions have been studied in detail. X-ray powder diffraction patterns show that the cobalt powder is hexagonal crystallite. The average particle size of the ultrafine cobalt powder is 55 nm.

  17. Nitrogen-Doped Carbon Nanoparticles for Oxygen Reduction Prepared via a Crushing Method Involving a High Shear Mixer

    Directory of Open Access Journals (Sweden)

    Lei Shi

    2017-09-01

    Full Text Available The disposal of agricultural wastes such as fresh banana peels (BPs is an environmental issue. In this work, fresh BPs were successfully transformed into nitrogen-doped carbon nanoparticles (N-CNPs by using a high shear mixer facilitated crushing method (HSM-FCM followed by carbonization under Ar atmosphere. Ammonia-activated N-CNPs (N-CNPs-NH3 were prepared via subsequent ammonia activation treatments at a high temperature. The as-prepared N-CNPs and N-CNPs-NH3 materials both exhibited high surface areas (above 700 m2/g and mean particle size of 50 nm. N-CNPs-NH3 showed a relatively higher content of pyridinic and graphitic N compared to N-CNPs. In alkaline media, N-CNPs-NH3 showed superior performances as an oxygen reduction reaction (ORR catalyst (E0 = −0.033 V, J = 2.4 mA/cm2 compared to N-CNPs (E0 = 0.07 V, J = 1.8 mA/cm2. In addition, N-CNPs-NH3 showed greater oxygen reduction stability and superior methanol crossover avoidance than a conventional Pt/C catalyst. This study provides a novel, simple, and scalable approach to valorize biomass wastes by synthesizing highly efficient electrochemical ORR catalysts.

  18. Community-Managed Disaster Risk Reduction : Investing in Resilience. A report prepared for Cordaid

    NARCIS (Netherlands)

    Gordon, A.N.

    2012-01-01

    Cordaid has been supporting community-managed disaster risk reduction (CMDRR) and drought cycle management (DCM) in the Horn of Africa for eight years. Many evaluations have pointed to successful outcomes but quantitative data are scarce. The aim of this study was to verify the extent to which Corda

  19. Preparation, characterization, and photocatalytic performance of Ce2S3 for nitrobenzene reduction

    Science.gov (United States)

    Chen, Shifu; Zhang, Huaye; Fu, Xianliang; Hu, Yingfei

    2013-06-01

    Ce2S3 photocatalysts were synthesized by a co-precipitation method using cerium nitrate and thioacetamide as raw materials. The samples were characterized by X-ray powder diffraction analysis, UV-visible diffuse reflectance spectroscopy, scanning electron microscopy, and differential thermal analysis. Photocatalytic reduction of nitrobenzene (NB) under UV or visible light illumination was used to evaluate the photocatalytic activity of the Ce2S3 samples. The result indicated that the sample prepared at 300 °C for 12 h exhibited the highest activity. For 140 mL 8.13 × 10-4 mol/L of NB in methanol solvent, after illumination for 5 h, about 43.9% and 34.7% of NB were reduced to aniline over the sample under UV and visible light irradiation, respectively. The effects of the catalyst amount, illumination time, and sorts of solvent on the photocatalytic performance were investigated specifically. The reduction process of NB over Ce2S3 was finally discussed.

  20. Single crystalline multi-petal Cd nanoleaves prepared by thermal reduction of CdO

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Waheed S. [Research Centre of Materials Science, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); National Institute for Biotechnology and Genetic Engineering (NIBGE), P.O. Box No. 577, Jhang Road, Faisalabad (Pakistan); Cao, Chuanbao, E-mail: cbcao@bit.edu.cn [Research Centre of Materials Science, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Aslam, Imran; Ali, Zulfiqar; Butt, Faheem K.; Mahmood, Tariq; Nabi, Ghulam [Research Centre of Materials Science, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Ihsan, Ayesha [National Institute for Biotechnology and Genetic Engineering (NIBGE), P.O. Box No. 577, Jhang Road, Faisalabad (Pakistan); Usman, Zahid [Research Centre of Materials Science, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Rehman, Asma [National Institute for Biotechnology and Genetic Engineering (NIBGE), P.O. Box No. 577, Jhang Road, Faisalabad (Pakistan)

    2013-02-15

    Highlights: ► Cd nanoleaves are obtained on abraded Cu substrate by thermal reduction of CdO. ► Vapour solid (VS) growth mechanism governs the formation of Cd nanoleaves (CdNLs). ► PL spectrum for CdNLs exhibits a strong ultraviolet (UV) emission band at 353 nm. ► UV band is attributed to interband radiative recombination under Xe illumination. -- Abstract: Multi-petal cadmium metal nanoleaves with 30–40 nm thickness were fabricated on abraded copper substrate by simple thermal reduction of cadmium oxide (CdO) powder at 1050 °C inside horizontal tube furnace (HTF) under nitrogen gas flow. The structural, compositional and morphological characterizations of the as-prepared cadmium nanoleaves (CdNLs) were performed by X-ray diffraction, energy dispersive X-ray spectroscopy, scanning electron microscopy, high resolution transmission electron microscopy and selected area electron diffraction. Non-catalytic vapour–solid (VS) process based growth mechanism governing the formation of CdNLs has been proposed and discussed briefly. Photoluminescence (PL) spectrum for CdNLs measured at room temperature exhibited a single prominent emission band at 353 nm which may either be ascribed to surface oxidation effects or interband radiative recombination under Xe light illumination.

  1. Low-cost Radon Reduction Pilot Study

    Energy Technology Data Exchange (ETDEWEB)

    Rose, William B. [Univ. of Illinois, Urbana-Champaign, IL (United States); Francisco, Paul W. [Univ. of Illinois, Urbana-Champaign, IL (United States); Merrin, Zachary [Univ. of Illinois, Urbana-Champaign, IL (United States)

    2015-09-01

    The U.S. Department of Energy's Building America research team Partnership for Advanced Residential Retrofits conducted a primary scoping study on the impact of air sealing between the foundation and the living space on radon transport reduction across the foundation and living space floor assembly. Fifteen homes in the Champaign, Illinois, area participated in the study. These homes were instrumented for hourly continuous radon measurements and simultaneous temperature and humidity measurements. Blower door and zone pressure diagnostics were conducted at each house. The treatments consisted of using air-sealing foams at the underside of the floor that separated the living space from the foundation and providing duct sealing on the ductwork that is situated in the foundation area. The hypothesis was that air sealing the floor system that separated the foundation from the living space should better isolate the living space from the foundation; this isolation should lead to less radon entering the living space from the foundation. If the hypothesis had been proven, retrofit energy-efficiency programs may have chosen to adopt these isolation methods for enhanced radon protection to the living space.

  2. Preparation

    Directory of Open Access Journals (Sweden)

    M.M. Dardir

    2014-03-01

    Full Text Available Some hexanamide-mono and di-linoleniate esters were prepared by the reaction of linolenic acid and hexanamide (derived from the reaction of hexanoic acid and diethanolamine. The chemical structure for the newly prepared hexanamide-mono and di-linoleniate esters were elucidated using elemental analysis, (FTIR, H 1NMR and chemical ionization mass spectra (CI/Ms spectroscopic techniques. The results of the spectroscopic analysis indicated that they were prepared through the right method and they have high purity. The new prepared esters have high biodegradability and lower toxicity (environmentally friendly so they were evaluated as a synthetic-based mud (ester-based mud for oil-well drilling fluids. The evaluation included study of the rheological properties, filtration and thermal properties of the ester based-muds formulated with the newly prepared esters compared to the reference commercial synthetic-based mud.

  3. STUDY ON THE PREPARATION OF BORON CARBIDE POWER BY CARBOTHERMAL REDUCTION METHOD%碳热还原法制备碳化硼粉末的工艺研究

    Institute of Scientific and Technical Information of China (English)

    于国强; 刘维良; 欧阳瑞丰; 李友宝

    2012-01-01

    采用碳热还原法制备了碳化硼粉末样品,讨论了硼碳比、煅烧合成和粉碎过程等工艺参数对其粉末性能的影响。借助XRD分析手段测试了其成分,并用化学方法分析了粉末的总碳含量,用激光粒度分布仪测试了其粒度分布。实验结果表明:以工业用硼酸和炭黑为原料,在1700~1850℃、保温0.5~1h煅烧合成能制得纯度较高的碳化硼粉末。其总碳含量为20.7%,接近理论值。中位径为32.56μm,经球磨粉碎后,其中位径可以达到2.42μm。%The boron carbide power was manufactured by carbothermal reduction method. The parameters which may have great influence to its performance are also discussed. The composition was analyzed by X-ray diffraction (XRD) . The total carbon content was analyzed by chemical method. The particle size distribution was tested by laser particle size analyzer. Experimental results show that when the boric acid and carbon black were selected as starting materials, sintered at 1700-1850℃ for 0.5-1h, high purity boron carbide power can be got. The total carbon content was 20.7%, which is close to the theoretical value. After milling, the median diameter can reach 2.42 μ m from 32.56 μm.

  4. Preparation of silver nanoparticles/polydopamine functionalized polyacrylonitrile fiber paper and its catalytic activity for the reduction 4-nitrophenol

    Science.gov (United States)

    Lu, Shixiang; Yu, Jianying; Cheng, Yuanyuan; Wang, Qian; Barras, Alexandre; Xu, Wenguo; Szunerits, Sabine; Cornu, David; Boukherroub, Rabah

    2017-07-01

    The study reports on the preparation of polyacrylonitrile fiber paper (PANFP) functionalized with polydopamine (PD) and silver nanoparticles (Ag NPs), named as Ag NPs/PD/PANFP. The composite material was obtained via a simple two-step chemical process. First, a thin polydopamine layer was coated onto the PANFP surface through immersion into an alkaline dopamine (pH 8.5) aqueous solution at room temperature. The reductive properties of polydopamine were further exploited for the deposition of Ag NPs. The morphology and chemical composition of the composite material were characterized using scanning electron microscopy (SEM), X-ray diffraction pattern (XRD) and X-ray photoelectron spectroscopy (XPS). The catalytic activity of the nanocomposite was evaluated for the reduction of 4-nitrophenol using sodium borohydride (NaBH4) at room temperature. The Ag NPs/PD/PANFP displayed good catalytic performance with a full reduction of 4-nitrophenol into the corresponding 4-aminophenol within 30 min. Moreover, the composite material exhibited a good stability up to 4 cycles without a significant loss of its catalytic activity.

  5. The analysis of cytotoxicity of an experimental preparation used for the reduction of dentin hypersensitivity.

    Science.gov (United States)

    Tanasiewicz, Marta; Skucha-Nowak, Małgorzata; Gibas, Mirosław; Pawlak, Justyna; Więckiewicz, Włodzimierz; Mertas, Anna; Król, Wojciech

    2017-01-01

    The problem of effective treatment of dentin hypersensitivity is still valid and not fully resolved. The aim of the study was to evaluate the potential toxicity against body tissues of an experimental preparation which is supposed to reduce dentin hypersensitivity and to compare it to a commercial formulation Seal & Protect (Dentsply) by means of measuring the activity of mitochondrial dehydrogenases (the MTT assay). The study used an original protective formulation which is supposed to eliminate hypersensitivity of dentin. A commercial preparation Seal & Protect (Dentsply) was used as the comparative material. Cytotoxic activity of the tested preparations (experimental and commercial) on murine lymphocyte cells CCL-1™ (NCTC clone 929) was determined in indirect contact with the use of the MTT test that measured the activity of the mitochondrial dehydrogenase enzyme. A comparison of the results obtained in the MTT assay for the commercial preparation Seal & Protect (Dentsply) and the experimental formulation indicates that an experimental formulation has considerably lower cytotoxicity before polymerization, when compared to the commercial formulation, regardless of its dilution. However, after the polymerization of the commercial formulation was completed, its parameters improved significantly, especially for higher dilution values (1 : 10 and 1 : 15). Results for the experimental formulation are higher, particularly for the dilution value of 1 : 5. The overall summary of the results obtained from the MTT assay for the commercial preparation Seal & Protect (Dentsply) and the experimental formulation indicates that the experimental formulation had a significantly lower cytotoxicity before polymerization in comparison with the commercial formulation, regardless of dilution. Estimating the biocompatibility of a given material is not simple, and measurement methods are rapidly evolving, as more and more is known about the interaction between dental materials and

  6. Reduction of the nitro group during sample preparation may cause underestimation of the nitration level in 3-nitrotyrosine immunoblotting

    DEFF Research Database (Denmark)

    Söderling, Ann-Sofi; Hultman, Lena; Delbro, Dick

    2007-01-01

    of inflammatory stimulated rat abdominal, liver and lung tissue homogenates caused no immunoreactivity, in contrast to a polyclonal nitrotyrosine antibody applied in fixed and non-fixed tissues. Western blot studies using both mono- and polyclonal antibodies showed a temperature- and heme group......We noted differences in the antibody response to 3-nitrotyrosine (NO(2)Tyr) in fixed and non-fixed tissues, and studied therefore potential problems associated with non-fixed tissues in Western blot analyses. Three different monoclonal anti-nitrotyrosine antibodies in Western blot analysis...... is not detected by anti-NO(2)Tyr antibodies. Western blot analysis may therefore underestimate the level of tissue nitration, and factors causing a reduction of NO(2)Tyr during sample preparation might conceal the actual nitration of proteins....

  7. Preparation of cu/fes nanoparticles by mechanochemical reduction of copper sulphide

    DEFF Research Database (Denmark)

    Balaz, P.; Takacs, L.; Jiang, Jianzhong

    2002-01-01

    mechanochemical reduction of copper sulphide by elemental iron. Platelets of Cu/FeS nanoparticles are formed as aggregates, tenths of micrometers in diameter. However, the average grain size of the freshly formed copper is between 10 and 25 nanometers depending on the milling conditions.......The mechanochemical reduction of copper sulphide with elemental iron was studied. The methods of XPS, SEM, EDX, and low temperature nitrogen sorption were used to analyse the surface composition and the composite particles formed from elemental copper and hexagonal 2C-troilite. The study...... of the mechanism and kinetics of the mechanochemical reaction by magnetic measurements, XRD and Mossbauer spectroscopy has revealed the details of the process.The transformations of copper sulphide, the synthesis of cubic FeS and its transformation to the hexagonal form are associated with the primary...

  8. Preparation of aniline from photocatalytic reduction of nitrobenzene using Pt/Nd{sub 2}O{sub 3} nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Mohamed, R.M., E-mail: mhmdouf@gmail.com

    2015-11-05

    In this manuscript, a template method was used to synthesis Pt-doped Nd{sub 2}O{sub 3} nanostructures with controlled Pt doping contents. The characterizations illustrated that the obtained samples have ultra high surface area (190 m{sup 2}/g), high crystallinity, small grain size (20 nm) and hollow spherical like morphology. Also, the band gap of the Pt-doped Nd{sub 2}O{sub 3} nanostructures can be controlled by controlling the Pt contents. The photocatalytic activity of the Pt-doped Nd{sub 2}O{sub 3} nanostructures samples was studied by studying the reduction of nitrobenzene into aniline using visible light irradiation. The photocatalytic performance of Nd{sub 2}O{sub 3} was enhanced by Pt doping. This can be attributed to the fact that the trapping effect of the Pt-doped Nd{sub 2}O{sub 3} nanostructures and the red shift of absorption edge. The study result provides an effective method to create different photocatalysts with enhanced visible-light-driven photocatalytic performance. - Highlights: • Pt-doped Nd{sub 2}O{sub 3} hollow sphere was prepared by a template method. • Photocatalytic preparation of aniline under visible light was dependent on wt % of Pt. • Catalyst re-use revealed the present photocatalyst remain effective and active after five cycles.

  9. Direct Measurement of Light Speed Reduction in a Rubidium Vapour Medium Coherently Prepared by Electromagnetically Induced Transparency

    Institute of Scientific and Technical Information of China (English)

    涂鲜花; 王谨; 江开军; 何明; 李可; 仲嘉琪; 詹明生

    2003-01-01

    We have experimentally observed the reduction of light speed in a rubidium vapour medium coherently prepared by electromagnetically induced transparency.The light speed reduction was deduced by directly measuring the time delay of a probe light when it passed through the medium.The time delay varies with the intensity of the coupling laser,and the typical time delay we recorded was 1.8 μs,corresponding to a light speed of 56000m/s.

  10. Nickel oxide reduction studied by environmental TEM

    DEFF Research Database (Denmark)

    Jeangros, Q.; Hansen, Thomas Willum; Wagner, Jakob Birkedal;

    2012-01-01

    In situ reduction of an industrial NiO powder is performed under 1.3 mbar of H2 (2 mlN/min) in a differentially pumped FEI Titan 80-300 environmental transmission electron microscope (ETEM). Images, diffraction patterns and electron energy loss spectra (EELS) are acquired to monitor the structura...

  11. Studies in the carbothermic reduction of phosphogypsum

    Science.gov (United States)

    Kale, Bharat B.; Pande, Anita R.; Gokarn, Ashok N.

    1992-10-01

    Phosphogypsum has been reduced in the solid state by active charcoal both in the presence and absence of catalysts. Kinetic data could be fitted to the modified volume reaction model. Mixed catalysts like potassium dichromate were found to enhance the reaction rate quite satisfactorily. This result could be fruitfully employed during reduction with industrial coke also.

  12. Electrocatalytic carbon dioxide reduction - a mechanistic study

    NARCIS (Netherlands)

    Schouten, Klaas Jan Schouten

    2013-01-01

    This thesis presents new insights into the reduction of carbon dioxide to methane and ethylene on copper electrodes. This electrochemical process has great potential for the storage of surplus renewable electrical energy in the form of hydrocarbons. The research described in this thesis focuses on t

  13. Preparation of Al-Si Master Alloy by Electrochemical Reduction of Volcanic Rock in Cryolite Molten Salt

    Science.gov (United States)

    Liu, Aimin; Shi, Zhongning; Xu, Junli; Hu, Xianwei; Gao, Bingliang; Wang, Zhaowen

    2016-06-01

    Volcanic rock found in the Longgang Volcano Group in Jilin Province of China has properties essentially similar to Apollo lunar soils and previously prepared lunar soil simulants, such as Johnson Space Center Lunar simulant and Minnesota Lunar simulant. In this study, an electrochemical method of preparation of Al-Si master alloy was investigated in 52.7 wt.%NaF-47.3 wt.%AlF3 melt adding 5 wt.% volcanic rock at 1233 K. The cathodic electrochemical process was studied by cyclic voltammetry, and the results showed that the cathodic reduction of Si(IV) is a two-step reversible diffusion-controlled reaction. Si(IV) is reduced to Si(II) by two electron transfers at -1.05 V versus platinum quasi-reference electrode in 52.7 wt.%NaF-47.3 wt.%AlF3 molten salt adding 5 wt.% volcanic rock, while the reduction peak at -1.18 V was the co-deposition of aluminum and silicon. In addition, the cathodic product obtained by galvanostatic electrolysis for 4 h was analyzed by means of x-ray diffraction, x-ray fluorescence, scanning electron microscopy and energy dispersive spectrometry. The results showed that the phase compositions of the products are Al, Si, Al5FeSi, and Al3.21Si0.47, while the components are 90.5 wt.% aluminum, 4.4 wt.% silicon, 1.9 wt.% iron, and 0.2 wt.% titanium.

  14. Nonlinear-Optical and Fluorescent Properties of Ag Aqueous Colloid Prepared by Silver Nitrate Reduction

    Directory of Open Access Journals (Sweden)

    Xiaoqiang Zhang

    2010-01-01

    Full Text Available The nonlinear-optical properties of metal Ag colloidal solutions, which were prepared by the reduction of silver nitrate, were investigated using Z-scan method. Under picosecond 532 nm excitation, the Ag colloidal solution exhibited negative nonlinear refractive index (n2=−5.17×10−4 cm2/W and reverse saturable absorption coefficient (β=4.32 cm/GW. The data fitting result of optical limiting (OL response of metal Ag colloidal solution indicated that the nonlinear absorption was attributed to two-photon absorption effect at 532 nm. Moreover, the fluorescence emission spectra of Ag colloidal solution were recorded under excitations at both 280 nm and 350 nm. Two fluorescence peaks, 336 nm and 543 nm for 280 nm excitation, while 544 nm and 694 nm for 350 nm excitation, were observed.

  15. Degradation kinetics of peptide-coupled alginates prepared via the periodate oxidation reductive amination route.

    Science.gov (United States)

    Dalheim, Marianne Ø; Ulset, Ann-Sissel T; Jenssen, Ina Beate; Christensen, Bjørn E

    2017-02-10

    Biomaterials based on peptide-coupled alginates must provide both optimal biological environments and tuneable stability/degradation profiles. The present work investigates the degradation pattern and kinetics of peptide-coupled alginates prepared via the periodate oxidation reductive amination route. Alginates degrade slowly (non-enzymatically) under physiological conditions by acid-catalysed hydrolysis and alkali-catalysed β-elimination, both operating simultaneously but dominated by the latter. While periodate oxidation alone largely increases the rate of β-elimination, substitution restores the susceptibility towards β-elimination to that of the parent alginate. For acid hydrolysis the rate of depolymerization is proportional to the degree of substitution, being approximately one order of magnitude larger than the parent alginate, but still lower than for the corresponding materials with fully reduced dialdehydes. Results also suggest a composition-dependent preference for substitution at C2 or C3. These results demonstrate how the various chemistries introduced by the coupling provide useful means to tune the biodegradability profiles.

  16. Preparation of Bimetallic Pd-Co Nanoparticles on Graphene Support for Use as Methanol Tolerant Oxygen Reduction Electrocatalysts

    Directory of Open Access Journals (Sweden)

    R. N. Singh

    2012-12-01

    Full Text Available Graphene-supported (40-x wt% Pd x wt% Co (0≤x≤13.33 alloys/composites have been prepared by a microwave-assisted polyol reduction method and been investigated for their structural and electrocatalytic properties for the oxygen reduction reaction (ORR in 0.5 M H2SO4 at 298 K. The study demonstrated that the bimetallic Pd-Co composite nanoparticles are, in fact, alloy nanoparticles with fcc crystalline structure. Partial substitution of Pd by Co (from 3.64 to 13.33 wt% in 40 wt% Pd/graphene decreases the lattice parameter as well as the crystallite size and increases the apparent catalytic activity, the latter, however, being the greatest with 8 wt% Co. The ORR activity of the active 32 wt% Pd 8wt% Co is found to be considerably low when it was deposited on the support multiwall carbon nanotubes under similar conditions. The rotating disk electrode study indicated that the ORR on 32 wt% Pd 8 wt% Co/GNS in 0.5 M H2SO4 follows approximately the four-electron pathway.

  17. Selective catalytic reduction of NOx by hydrocarbons over Fe/ZSM5 prepared by sublimation of FeCl3

    NARCIS (Netherlands)

    Battiston, A.A.

    2003-01-01

    Selective Catalytic Reduction of NOx by Hydrocarbons over Fe/ZSM5 Prepared by Sublimation of FeCl3. Characterization and Catalysis Nitrogen oxides (NOx) are unwanted by-products of combustion. They are generated primarily from motor vehicles and stationary sources, like power stations and indust

  18. Investigation on the thermodynamic analysis, preparation and characterization of LaNi5 - hydrogen storage alloy by magnesiothermic reduction diffusion process

    Directory of Open Access Journals (Sweden)

    Giresan G.

    2016-01-01

    Full Text Available The present investigation focuses on the preparation of LaNi5 intermetallic compound by “Metallothermic reduction diffusion process”. Experiments were carried out using oxides and chlorides of La and Ni metal powders as the raw materials with granular Mg powder as the reductant. The thermal reduction process was carried out at 900 ºC for 9 hrs in Ar atmosphere. After the completion of reaction, the contents were purified by treating with dilute acetic acid followed by de-ionized water. Thermodynamic feasibility studies were carried out to determine the probabilistic nature of formation of the desired compound. Thermal analysis was carried out to find the dissociation and decomposition temperature of the reactants. The phase purity and the elemental composition of the alloy were assessed by XRD and EDX analyses. The morphological features of the prepared powders were examined by SEM. From this study, it has been concluded that LaNi5 alloy can be prepared with an appreciable purity by the Metallothermic reduction diffusion process.

  19. Effect of Na2CO3 Addition on Carbothermic Reduction of Copper Smelting Slag to Prepare Crude Fe-Cu Alloy

    Science.gov (United States)

    Guo, Zhengqi; Zhu, Deqing; Pan, Jian; Yao, Weijie; Xu, Wuqi; Chen, Jinan

    2017-09-01

    Copper smelting slag is a useful secondary resource containing high iron and copper, which can be utilized to prepare crude Fe-Cu alloy by a direct reduction-magnetic separation process for making weathering-resistant steel. However, it is difficult to recover iron and copper from the slag by direct reduction since the iron mainly occurs in fayalite and the copper is held in copper sulfide. Therefore, enhancement reduction of copper slag is conducted to improve the recovery of copper and iron. Additives such as Na2CO3 has been proven to be capable of reinforcing the reduction of refractory iron ore. In this research, the effect of Na2CO3 on the carbothermic reduction of copper slag was investigated, and phase transformations during reduction and the distributing characteristics of iron and copper in the alloy and non-metallic phases of the reduced pellets were also studied. The results show that the metallization rate of iron and copper was increased with the addition of Na2CO3, leading to higher iron and copper recovery in Fe-Cu alloy powder. X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) results confirm that Na2CO3 is capable of enhancing the reduction of fayaltie, copper silicate and copper sulfide, which agrees well with thermodynamic analysis. Furthermore, the reduction mechanism of copper slag was demonstrated based on systematic experimental observations.

  20. Plasma chemical reduction of model corrosion brass layers prepared in soil

    Science.gov (United States)

    Radkova, Lucie; Mikova, Petra; Prikryl, Radek; Krcma, Frantisek

    2016-08-01

    The brass plates of (50 × 10 × 1) mm3 were prepared with model corrosion layer because the real archaeological artifacts could be damaged during the method optimization. Samples corroded naturally more than 2 years in the soil. Excavated samples were treated in the low pressure (150 Pa) quartz glass plasma reactor (90 cm long and 9.5 cm in diameter) which was surrounded by two external copper electrodes supplied by radio-frequency generator (13.56 MHz). The experiments were carried out in a hydrogen-argon gas mixture at mass flows of 30 sccm for hydrogen and 20 sccm for argon for 90 min. The plasma power was 100, 200, 300 and 400 W in continuous and pulsed mode. Maximum sample temperature was set at 120 °C. The whole process was monitored by optical emission spectroscopy and the obtained data were used to calculate the relative intensity of OH radicals and rotational temperature. The results showed that the higher power had the greater maximum intensity of the OH radicals and rapidly degraded the corrosion layer. Corrosion layer was not completely removed during the reduction, but due to the reactions which occur in the plasma corrosion layer became brittle and after plasma chemical treatment can be removed easily. Finally, the SEM-EDX analysis of the surface composition confirmed removal of chlorine and oxygen from the corrosion products layers. Contribution to the topical issue "6th Central European Symposium on Plasma Chemistry (CESPC-6)", edited by Nicolas Gherardi, Ester Marotta and Cristina Paradisi

  1. Carbohydrazide-dependent reductant for preparing nitrogen-doped graphene hydrogels as electrode materials in supercapacitor

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Man [Resources and Environmental Engineering, Shandong University of Technology, Zibo 255049 (China); Xing, Ling-Bao, E-mail: lbxing@sdut.edu.cn [School of Chemical Engineering, Shandong University of Technology, Zibo 255049 (China); Zhang, Jing-Li; Hou, Shu-Fen; Zhou, Jin; Si, Weijiang; Cui, Hongyou [School of Chemical Engineering, Shandong University of Technology, Zibo 255049 (China); Zhuo, Shuping, E-mail: zhuosp_academic@yahoo.com [School of Chemical Engineering, Shandong University of Technology, Zibo 255049 (China)

    2016-04-15

    Graphical abstract: - Highlights: • Three-dimensional nitrogen-doped graphene hydrogels (NGHs) were prepared. • Carbohydrazide was used as reducing and doping agents. • NGHs exhibited relatively good electrochemical properties in supercapacitor. • NGHs with different doping of N demonstrated different performances in supercapacitors. - Abstract: Three-dimensional (3D) nitrogen-doped graphene hydrogels (NGHs) are designed and synthesized in an efficient and fast way by using a strong reductant of carbohydrazide as reducing and doping agent in an aqueous solution of graphene oxide (GO). The transformation of GO suspension to the hydrogels can be completed in 1 h, which can be confirmed by X-ray powder diffraction (XRD), Raman spectroscopy, and Fourier transform infrared spectroscopy (FT-IR). With adding different amounts of carbohydrazide, the obtained NGHs behave different doping of N and unlike performances in supercapacitors, which can be demonstrated by elemental analysis and X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), N{sub 2} sorption experiments, and electrochemical measurements, respectively. According to the network architectures, the NGHs all exhibited high specific capacitance, NGHs-1, NGHs-2, NGHs-5 and NGHs-10 showed specific capacitance at 167.7, 156.8, 140.4 and 119.3 F g{sup −1} at 1 A g{sup −1} in KOH electrolyte. The specific capacitance can still be maintained for 80.5, 79.5, 80.3 and 78.6% with an increase of the discharging current density of 10 A g{sup −1}, respectively. More interestingly, the NGHs-1 based supercapacitor also exhibited good electrochemical stability and high degree of reversibility in the long-term cycling test (81.5% retention after 4000 cycles).

  2. Synthesis and magnetic properties of cobalt nickel nanoparticles prepared by chemical reduction methods

    Science.gov (United States)

    Patel, Jalpa Dipesh

    The purpose of this work was to prepare and characterise CoxNii.x/CoNiO core-shell magnetic nanoparticles which showed magnetic exchange bias. The particles were synthesised using a variety of stabilising surfactants and nucleating seeds, via the polyol reduction method. The surfactants were used to coat nanoparticles of various diameters, to prevent agglomeration and oxidation. A mixture of 1:1 oleic acid: oleylamine was found to be the best stabilising agent for the particles as it protected against complete oxidation whilst allowing a partial oxide shell to form. Phosphine-based surfactants yielded particles with spherical morphologies. However, these particles were too small to support oxide-shell growth, and oxidised fully to antiferromagnetic phases. The nucleation of particles was probed using homogeneous and heterogeneous methods. Homogeneous nucleation resulted in particles which had predominantly oxidised to the core, and therefore did not yield pronounced exchange bias effects. Heterogeneous nucleation was attempted using various seeding techniques and seed materials. Platinum seeds were found to be the most effective in controlling the size of CoxNii_x nanoparticles. They yielded larger particles with core-shell morphology. Following optimisation of the synthesis conditions, a compositional series of CoxNii.x nanoparticulate composite alloys were made. All samples were analysed using TEM to determine the size and structure of the individual particles. A number of other techniques including X-ray diffraction, X-ray photoelectron spectroscopy, Energy-dispersive X-ray analysis, Electron energy loss spectroscopy and Thermogravimetric magnetic analysis, were also used to fully characterise the phase, crystallinity, composition and oxidation in individual particles. The magnetic properties of the particles, made using the various reaction conditions, were measured using the SQUID technique. Exchange bias has been observed in several of the alloyed samples in

  3. Reduction study of oxidized two-dimensional graphene-based materials by chemical and thermal reduction methods

    Science.gov (United States)

    Douglas, Amber M.

    Graphene is a two-dimensional (2D) sp2-hybridized carbon-based material possessing properties which include high electrical conductivity, ballistic thermal conductivity, tensile strength exceeding that of steel, high flexural strength, optical transparency, and the ability to adsorb and desorb atoms and molecules. Due to the characteristics of said material, graphene is a candidate for applications in integrated circuits, electrochromic devices, transparent conducting electrodes, desalination, solar cells, thermal management materials, polymer nanocomposites, and biosensors. Despite the above mentioned properties and possible applications, very few technologies have been commercialized utilizing graphene due to the high cost associated with the production of graphene. Therefore, a great deal of effort and research has been performed to produce a material that provides similar properties, reduced graphene oxide due (RGO) to the ease of commercial scaling of the production processes. This material is typically prepared through the oxidation of graphite in an aqueous media to graphene oxide (GO) followed by reduction to yield RGO. Although this material has been extensively studied, there is a lack of consistency in the scientific community regarding the analysis of the resulting RGO material. In this dissertation, a study of the reduction methods for GO and an alternate 2D carbon-based material, humic acid (HA), followed by analysis of the materials using Raman spectroscopy and Energy Dispersive X-ray Spectroscopy (EDS). Means of reduction will include chemical and thermal methods. Characterization of the material has been carried out on both before and after reduction.

  4. Electro catalyst of platinum prepared by CVD for the oxygen reduction reaction; Electrocatalizador de platino preparado por CVD para la reaccion de reduccion de oxigeno

    Energy Technology Data Exchange (ETDEWEB)

    Garcia C, M.A.; Fernandez V, S.M. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Vargas G, J.R. [IPN, ESIQIE, 07300 Mexico D.F. (Mexico)

    2004-07-01

    In this work it is reported the preparation and characterization of platinum films obtained by the technique of chemical vapor deposition at low pressure, better well-known as LPCVD for their initials in English (Low Pressure Chemical Vapor Deposition). The technique has several industrial applications and in this work it is explored their possible use to prepare applicable electrocatalysts in fuel cells. The films were characterized by XRD, SEM, EDS and they were proven for to determine their acting in the Oxygen reduction reaction (Orr) in sulfuric acid 0.5 M, the results show that the material presents good activity for the reaction in study. (Author)

  5. Compression and model reduction: A case study

    Energy Technology Data Exchange (ETDEWEB)

    LoFaro, T. [Washington State Univ., Pullman, WA (United States); Kopell, N. [Boston Univ., Boston, MA (United States)

    1995-12-31

    We discuss a method by which the dynamics of a network of coupled neurons can be captured in a one-dimensional map. The network used as an example of this technique consists of a pair of neurons, one of which is an endogenous burster and the other excitable, but not bursting in the absence of phasic input. The reduction is accomplished by decomposing the flow into fast and slow subsystems, each operating on a distinct time scale. A {open_quotes}map of knees{close_quotes} is constructed using singular perturbation techniques. A concise expression for this map is developed by introducing time coordinates to each stable branch of the slow manifold. The compression associated with the fast subsystem is used to determine the qualitative properties of the map.

  6. Comparison of reduction disintegration characteristics of TiO2-rich burdens prepared with sintering process and composite agglomeration process

    Science.gov (United States)

    Yu, Zheng-wei; Li, Guang-hui; Liu, Chen; Zhou, Feng; Peng, Zhi-wei; Jiang, Tao

    2016-04-01

    To reveal the impact of the composite agglomeration process (CAP) on the reduction disintegration properties of TiO2-rich ironmaking burden for a blast furnace, the reduction disintegration indices (RDIs), mineral constituents, and microstructure of the products prepared by the CAP and the traditional sintering process (TSP) were investigated. The results showed that, compared to the sinter with a basicity of 2.0 prepared by the TSP, the RDI+6.3 and the RDI+3.15 of the CAP product with the same basicity increased by 28.2wt% and 13.7wt%, respectively, whereas the RDI-0.5 decreased by 2.7wt%. The analysis of the mineral constituents and microstructure of the products indicated that the decreasing titanohematite content decreased the volume expansion during reduction. Meanwhile, the decreasing perovskite content decreased its detrimental effect on the reduction disintegration properties. In addition, the higher silicoferrite of calcium and aluminum (SFCA) content improved the strength of the CAP product. Together, these factors result in an improvement of the RDI of the CAP products. In addition, compared to the sinter, the reduced CAP products clearly contained fewer cracks, which also led to mitigation of reduction disintegration.

  7. Comparison of reduction disintegration characteristics of TiO2-rich burdens prepared with sintering process and composite agglomeration process

    Institute of Scientific and Technical Information of China (English)

    Zheng-wei Yu; Guang-hui Li; Chen Liu; Feng Zhou; Zhi-wei Peng; Tao Jiang

    2016-01-01

    To reveal the impact of the composite agglomeration process (CAP) on the reduction disintegration properties of TiO2-rich iron-making burden for a blast furnace, the reduction disintegration indices (RDIs), mineral constituents, and microstructure of the products pre-pared by the CAP and the traditional sintering process (TSP) were investigated. The results showed that, compared to the sinter with a ba-sicity of 2.0 prepared by the TSP, the RDI+6.3 and the RDI+3.15 of the CAP product with the same basicity increased by 28.2wt%and 13.7wt%, respectively, whereas the RDI−0.5 decreased by 2.7wt%. The analysis of the mineral constituents and microstructure of the products indicated that the decreasing titanohematite content decreased the volume expansion during reduction. Meanwhile, the decreasing perovskite content decreased its detrimental effect on the reduction disintegration properties. In addition, the higher silicoferrite of calcium and aluminum (SFCA) content improved the strength of the CAP product. Together, these factors result in an improvement of the RDI of the CAP products. In addition, compared to the sinter, the reduced CAP products clearly contained fewer cracks, which also led to mitigation of reduction disintegration.

  8. Experimental study on Cr(Ⅵ) reduction by Pseudomonas aeruginosa

    Institute of Scientific and Technical Information of China (English)

    LIU Yun-guo; XU Wei-hua; ZENG Guang-ming; TANG Chun-fang; LI Cheng-feng

    2004-01-01

    Investigation on Cr(Ⅵ) reduction was conducted using Pseudomonas aeruginosa. The study demonstrated that the Cr(Ⅵ) can be effectively reduced to Cr(Ⅲ) by Pseudomonas aeruginosa. The effects of the factors affecting Cr(Ⅵ) reduction rate including carbon source type, pH, initial Cr(Ⅵ) concentration and amount of cells inoculum were thoroughly studied. Malate was found to yield maximum biotransformation, followed by succinate and glucose, with the reduction rate of 60.86%, 43.76% and 28.86% respectively. The optimum pH for Cr(Ⅵ) reduction was 7.0, with reduction efficiency of 61.71% being achieved. With the increase of initial Cr(Ⅵ) concentration, the rate of Cr(Ⅵ) reduction decreased. The reduction was inhibited strongly when the initial Cr(Ⅵ) concentration increased to 157 mg/L. As the amount of cells inoculum increased, the rate of Cr(Ⅵ) reduction also increased. The mechanism of Cr(Ⅵ) reduction and final products were also analysed. The results suggested that the soluble enzymes appear to be responsible for Cr(Ⅵ) reduction by Pseudomonas aeruginosa, and the reduced Cr(Ⅲ) was not precipitated in the form of Cr(OH)3.

  9. A novel co-precipitation method for preparation of Mn--Ce/TiO2 composites for NOx reduction with NH3 at low temperature.

    Science.gov (United States)

    Sheng, Zhongyi; Hu, Yufeng; Xue, Jianming; Wang, Xiaoming; Liao, Weiping

    2012-01-01

    Mn--Ce/TiO2 catalyst prepared by a novel co-precipitation method was used in this study for low-temperature selective catalytic reduction (SCR) of NOx with ammonia. The catalyst showed high activity and good SO2 resistance. The NO conversion on the catalyst increased to 100% when 700 ppm of SO2 flowed in, and reached 60.8% in 2.5 h. The characterized results indicated that the catalyst prepared by the new method had good dispersion of the active phase, uniform micro-size particles and large Brunauer-Emmett-Teller surface. The temperature programmed reduction and temperature programmed desorption experiments showed that the improvement in SCR activity on the Mn--Ce/TiO2 catalyst might be due to the increase of active oxygen species and the enhancement of NH3 chemisorption, both of which were conducive to NH3 activation.

  10. In situ reduction of as-prepared γ-Iron Oxide Nanoparticles

    DEFF Research Database (Denmark)

    Garbus, Pelle Gorm; Ahlburg, Jakob; Christensen, Mogens

    .L., et al., Size and Size Distribution Control of γ-Fe2O3 Nanocrystallites: An in Situ Study. Crystal Growth & Design, 2014. 14(3): p. 1307-1313.3.Bondesgaard, M., et al., Guide to by-products formed in organic solvents under solvothermal conditions. The Journal of Supercritical Fluids, 2016. 113: p. 166...... behind the structural development [1, 2] adds to the fundamental understanding of materials’ formation and can lead to new synthesis pathways. In this study, iron oxide (γ-Fe2O3) particles were heated to 400°C under a flow of H2/Ar mixture, while the process was followed by in situ synchrotron powder X......-iron oxide Fe2O3. The reduction of maghemite to body centered cubic (BCC) iron does not go through a detectable intermediate state.1.Jensen, K.M., et al., Mechanisms for iron oxide formation under hydrothermal conditions: an in situ total scattering study. ACS nano, 2014. 8(10): p. 10704-10714.2.Andersen, H...

  11. Mechanistic studies of carbon monoxide reduction

    Energy Technology Data Exchange (ETDEWEB)

    Geoffroy, G.L.

    1990-06-12

    The progress made during the current grant period (1 January 1988--1 April 1990) in three different areas of research is summarized. The research areas are: (1) oxidatively-induced double carbonylation reactions to form {alpha}-ketoacyl complexes and studies of the reactivity of the resulting compounds, (2) mechanistic studies of the carbonylation of nitroaromatics to form isocyanates, carbamates, and ureas, and (3) studies of the formation and reactivity of unusual metallacycles and alkylidene ligands supported on binuclear iron carbonyl fragments. 18 refs., 5 figs., 1 tab.

  12. Preparation of Polyacrylonitrile/Ferrous Chloride Composite Nanofibers by Electrospinning for Efficient Reduction of Cr(VI).

    Science.gov (United States)

    Zhou, Shilin; Liu, Fang; Zhang, Qian; Chen, Bor-Yann; Lin, Chin-Jung; Chang, Chang-Tang

    2015-08-01

    In this study, A novel adsorbent material of polyacrylonitrile (PAN)/ferrous chloride (FeCl2) composite nanofibers is prepared by electrospinning, a simple and effective method. The obtained composite nanofibers have a non-uniform morphology and structure and a large specific surface area of 13.8 m2 g-1. Fourier transform infrared spectroscopy (FTIR) revealed that Fe2+ was successful introduced into the composite nanofibers. Furthermore, the PAN/FeC12 composite nanofibers exhibited excellent performance in Cr removal, especially when reacted with reduction from a Cr(VI) standard containing solution, which has much faster removal efficiency than the previous report of Lin et al. (2011). The results of the adsorption isotherm show that the data fitted well to the Langmuir isotherm model. The maximum adsorption of chromium ions composite nanofibers is 108 mgCr/gFeCl2. An attempted model prediction of the transient dynamics of adsorption-desorption elucidated the feasible kinetic analysis of Cr6+ from the PAN/FeCl2 composite nanofibers. This kinetic modeling can be used both for adsorption of heavy metals wastewater and for organic-adsorption and biosorption of diverse wastewaters. The PAN/FeCl2 composite nanofibers producted in this study exhibit high efficiency in Cr(VI) removal from wastewater, and may be used as a reference for future investigation.

  13. Sonochemical preparation of stable porous MnO2 and its application as an efficient electrocatalyst for oxygen reduction reaction.

    Science.gov (United States)

    Zuo, Ling-Xia; Jiang, Li-Ping; Abdel-Halim, E S; Zhu, Jun-Jie

    2017-03-01

    Porous MnO2 as a non-noble metal oxygen reduction reaction (ORR) electrocatalyst was prepared by a simple sonochemical route. The as-prepared porous MnO2 exhibited higher electrocatalytic activity, superior stability and better methanol tolerance than commercial Pt/C catalyst in alkaline media. Furthermore, the ORR proceeded via a nearly four-electron pathway. Cyclic voltammetry (CV) and rotating-disk electrode (RDE) measurements verified that the ORR enhancement was attributed to the porous structure and good dispersity, which facilitated sufficient transport of ions, electrons, O2 and other reactants in the process of ORR. The results indicated that a facile and feasible sonochemical route could be used to prepare highly active porous MnO2 electrocatalyst for ORR, which might be promising for direct methanol fuel cells.

  14. Low-temperature selective catalytic reduction of NO on MnO(x)/TiO(2) prepared by different methods.

    Science.gov (United States)

    Jiang, Boqiong; Liu, Yue; Wu, Zhongbiao

    2009-03-15

    Catalysts based on MnO(x)/TiO(2) were prepared by sol-gel, impregnation, and coprecipitation methods for low-temperature selective catalytic reduction (SCR) of NO with NH(3). Among the catalysts, the sample prepared by sol-gel method had the best performance on both activity and SO(2) resistance. From the results of thermo gravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectrum (XPS), it was known that manganese oxides and titania existed in different phase in the samples prepared by three methods. Strong interaction, large surface area, high concentration of hydroxyl groups, high concentration of amorphous Mn on the surface might be the main reasons for the excellent performance of the catalysts.

  15. Study on the Electro-reduction of Perfluorodecalin

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The reduction ofperfluorodecalin was studied by the method of electrochemistry. The results indicated that the electrochemical reduction of perfluorodecalin was a multi-step reaction.The mechanism of the first consecutive reaction showed that it is to diffusion controlling step.

  16. Baker's yeast mediated reduction of substituted acenaphthenequinones: Regio- and enantioselective preparation of mono-hydroxyacenaphthenones

    Institute of Scientific and Technical Information of China (English)

    Xing Yong Wang; Jing Nan Cui; Wei Min Ren; Feng Li; Chun Liang Lu; Xu Hong Qian

    2007-01-01

    Baker's yeast mediated reduction of acenaphthenequinone within 4-10 h afforded mono-hydroxyacenaphthenone mainly with low enantioselectivity, the substrate and mono-hydroxyacenaphthenone product almost converted to dihydroxyacenaphthene after 48 h.By control of the reaction time and in the presence of DMF as co-solvent, the reduction of 6-substituted acenaphthenequinones under vigorous agitation afforded the corresponding 2-hydroxyacenaphthenones in 24-84% yields with 10-93% ee.

  17. SOFC anode reduction studied by in situ TEM

    DEFF Research Database (Denmark)

    Simonsen, Søren Bredmose; Wagner, Jakob Birkedal; Hansen, Thomas Willum;

    active Ni surface before operating the fuel cells. The reduction process was followed in the TEM while exposing a NiO/YSZ (YSZ = Y2O3-stabilized ZrO2) model anode to H2 at T = 250-1000⁰C. Pure NiO was used in reference experiments. Previous studies have shown that the reduction of pure NiO...... is a relatively rapid autocatalytic process. On the contrary, the reduction of NiO/YSZ is significantly slower, which indicates that the presence of YSZ inhibits the reduction of NiO. This study aims to obtain fundamental insight into this reduction mechanism and to explain the inhibitive influence of YSZ...

  18. Preparation and magnetic properties of nickel nanowires by reduction in ethylene glycol medium under the influence of magnetic field

    Science.gov (United States)

    Sun, Wanshuo; Cheng, Junsheng; Li, Lankai; Chen, Shunzhong; Chang, Kun

    2017-01-01

    Nickel nanowires have successfully been fabricated through a simple liquid reduction in ethylene glycol medium with a 0.3T magnetic field applied. The effect of uniform magnetic field and solvent on the morphology and the crystal structure of magnetic nickel were studied. Scanning electron microscope images and transmission electron scope images s how that the effect of the external magnetic field on the morphology of nickel nanowires. X-ray diffraction shows the crystal structure of as-prepared products. And a energy disperse spectroscopy and a vibrating sample magnetometer are used to analyze the composition and static magnetic properties. The results show that the straight wires with an average diameter of about 100 nm and a length of several microns were obtained and mainly composed by fcc structure in the solvent of ethylene glycol. Magnetic measurements show that the saturation magnetization of the as-obtained products in a 0.3 T external magnetic field is 36 emu/g, less than that of bulk nickel crystal, and the coercivity of them is 186 emu/g, larger than that of bulk crystal with the mole ratio of sodium borohydride to nickel sulfate is 1:1000. This kind of nanowires array has potential applications with the special one-dimensional structures.

  19. Ultramicroelectrode studies of oxygen reduction in polyelectrolyte membranes

    Energy Technology Data Exchange (ETDEWEB)

    Holdcroft, S.; Abdou, M.S.; Beattie, P.; Basura, V. [Simon Fraser Univ., Burnaby, BC (Canada). Dept. of Chemistry

    1997-12-31

    A study on the oxygen reduction reaction in a solid state electrochemical cell was presented. The oxygen reduction reaction is a rate limiting reaction in the operation of solid polymer electrolyte fuel cells which use H{sub 2} and O{sub 2}. Interest in the oxygen reduction reaction of platinum electrodes in contact with Nafion electrolytes stems from its role in fuel cell technology. The kinetics of the oxygen reduction reaction in different polyelectrolyte membranes, such as Nafion and non-Nafion membranes, were compared. The electrode kinetics and mass transport parameters of the oxygen reduction reaction in polyelectrolyte membranes were measured by ultramicroelectrode techniques. The major difference found between these two classes of membrane was the percentage of water, which is suggestive of superior electrochemical mass transport properties of the non-Nafion membranes. 2 refs. 1 fig.

  20. 直接还原含钛炉渣亚熔盐法制备钛白粉工艺研究%Study on Preparation of TiO2 Pigment with Sub-molten Salt Process from Titanium-bearing Slag Obtained in Direct-reduction Ironmaking

    Institute of Scientific and Technical Information of China (English)

    王淑奕; 金英杰; 初景龙; 齐涛

    2013-01-01

    Using titaniferous slag from the process of ‘ coal-based direct reduction in rotary hearth furnace -further reduction and smelting and separation in electric furnace’ as raw material,TiO2 Pigment with a content of titanium dioxide over 98% was produced by sub-molten salt process.The optimum testing conditions for the production were studied,aiming to find out the optimum reaction time,alkaline ratio,reaction temperature,and granularity of the raw material.After multistage solid-state ion exchange and removal of impurities,titaniferous solution (CTio2 =80 g/L,effective acid coefficient F =2.0) was prepared from the intermediate product sodium metatitantate.Through hydrolysis,metatitanic acid with a particle size of D (0.5) =.2 μn was obtained,and then it could be calcined to anatase TiO2 products.%以“转底炉煤基直接还原一电炉深还原、熔分工艺”得到的含钛炉渣为原料,经过亚熔盐法钛白工艺得到纯度在98%以上的二氧化钛产品.研究了亚熔盐法钛白工艺中反应最佳试验条件,得到最优的反应时间、碱矿比、反应温度、原料粒度;中间产物偏钛酸钠经多级固态离子交换、除杂制得钛液(CTio2=180 g/L、有效酸系数F=2.0);水解后制得偏钛酸粒度D(0.5)=1.2μm;经煅烧得到锐钛型二氧化钛产品.

  1. Predicting Marital Success with PREPARE: A Predictive Validity Study.

    Science.gov (United States)

    Fowers, Blaine J.; Olson, David H.

    1986-01-01

    Assessed the utility of the premarital inventory, PREPARE, in predicting marital success. Conducted a three-year follow-up study with couples (N=164) who took PREPARE during their engagement. Found that the PREPARE scores from three months before marriage could predict with 80-90% accuracy which couples were separated and divorced from those that…

  2. Preparation and Characterization of Chitosan-Humic Acid-Zerovalent Iron Nanocomposite for Nitrate Reduction in Water

    Directory of Open Access Journals (Sweden)

    Caroline Avosuahi Akinremi

    2016-01-01

    Full Text Available A new zerovalent iron chitosan-humic acid nanocomposite was prepared and tested for nitrate ion reduction in water. Humic acid was used for intramolecular cross-linking of the chitosan linear chains to increase the active sites on the chitosan biopolymer and then further used as a stabilizer to synthesize zerovalent iron nanoparticles by the reduction of iron (II chloride with sodium borohydride. Characterization of the products was carried out using infrared spectroscopy, scanning electron microscope, energy dispersive X-ray, and X-ray diffractometer. Batch experiments were conducted for the reduction of nitrate in water using different concentrations of the products in different concentrations of nitrate ion and at different contact time. The adsorption equilibrium data for the nitrate solution gave a favorable adsorption according to the Langmuir equation. Varying the nanocomposite-to-nitrate ion ratio generally led to faster nitrate reduction, with the pseudofirst-order rate constant for the adsorption increasing with increase in nanocomposite-to-nitrate ion ratio. Nitrate removal efficiency of zerovalent iron chitosan-humic acid nanocomposite was further confirmed using real water samples obtained from drainage waste and river with an initial nitrate concentration of 18.00±0.01 and 12.00±0.12 ppm, respectively. The reduction of nitrate in water using the nanocomposite was concluded to be highly effective.

  3. Enhanced magnetic properties of NiO powders by the mechanical activation of aluminothermic reduction of NiO prepared by a ball milling process

    Energy Technology Data Exchange (ETDEWEB)

    Padhan, Aneeta Manjari; Ravikumar, P. [Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039 (India); Saravanan, P. [Advanced Magnetic Lab, Defence Metallurgical Research Laboratory, Hyderabad 500058 (India); Alagarsamy, Perumal, E-mail: perumal@iitg.ernet.in [Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039 (India)

    2016-11-15

    We report the effect of mechanical activation on NiO–Al (x wt%) reduction reaction and resulting structural and magnetic properties by carrying out high-energy planetary ball milling. The pure NiO (un-milled) and milled NiO–Al (x≤2.5) powders exhibit face centered cubic structure, but the antiferromagnetic nature of pure NiO powder shows significant room temperature ferromagnetism with moderate moment and coercivity after milling due to non-stoichiometry in NiO caused by the defects, size reduction and oxidation of Ni. On the other hand, the addition of Al between 2.5 and 10% in NiO forms solid solution of NiO–Al with considerable reduction in the moment due to the atomic disorder. With increasing Al above 10%, NiO reduction reaction progresses gradually and as a result, the average magnetization increases from 0.57 to 4.3 emu/g with increasing Al up to 25%. A maximum of 91% reduction was observed for NiO–Al (40%) powders in 30 h of milling with a large increase in magnetization (~24 emu/g) along with the development of α-Al{sub 2}O{sub 3}. Thermomagnetization data reveal the presence of mixed magnetic phases in milled NiO powders and the component of induced ferromagnetic phase fades out with increasing Al due to the formation of Ni from the NiO–Al reduction reaction. The changes in the structural and magnetic properties are discussed on the basis of mechanical activation on the reduction of NiO by Al. The controlled reduction reaction with different Al content in NiO–Al is encouraging for the applications in catalysis and process of ore reduction. - Highlights: • Preparation of Ni/Al{sub 2}O{sub 3} nanocomposite by mechanical activation of NiO–Al reduction. • Study the effect of Al addition on the reduction reaction of NiO–Al powders. • Understand the change in the structural and microstructural properties of NiO–Al. • Investigate role of reduction of NiO by Al on resulting magnetic property of NiO–Al. • Study the magnetic phase

  4. Ruthenium nanoparticles for oxygen reduction and/or hydrogen oxidation, prepared by pyrolysis in a reducing atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Altamirano-Gutierrez, A.; Villagran-Naredo, J.L.A.; Jimenez-Sandoval, O. [Inst. Politecnico Nacional (Mexico). Centro de Investigacion y de Estudios Avanzados; Hernandez-Castellanos, R. [Centro de Investigacion y Desarrollo Technologic en Electroquimica (Mexico)

    2006-07-01

    An investigation of the synthesis, structural and electrochemical characterization of ruthenium-based materials prepared by pyrolysis was presented. Ru{sub 3}(CO){sub 12} materials were pyrolized in a hydrogen atmosphere at 80, 140, 360 and 460 degrees C. The materials were then characterized using Fourier Transform Infrared (FTIR) spectroscopy; X-ray diffraction (XRD) and scanning electron microscopy (SEM). Oxygen reduction reactions (ORR) and hydrogen oxidation reactions (HOR) were evaluated through the use of rotating disk electrode measurements in a 0.5 M hydrogen peroxide (H{sub 2}SO{sub 4}) electrolyte at room temperature. Results of the investigation indicated that the Ru{sub 3}(CO){sub 12} precursor was completely decarbonylated in H{sub 2} at 140 degrees C. Carbonyl group bands were observed when the materials were prepared at 80 degrees C due to the formation of an inactive Ru cluster resulting from a structural rearrangement of the cluster. Polarization curves indicated that the materials prepared at 140 degrees C were able to perform the ORR and HOR in an acid medium similar to the medium present in proton exchange (PE) fuel cells. The electrokinetic parameters indicated that the exchange current densities were of the same order as platinum (Pt) current densities, and that the ORR occurred via 4 electrons due to the direct formation of water. Tafel slope values for the HOR suggested that the mechanism of the reaction was related to Herovsky/Volmer types. It was concluded that the use of a reductive atmosphere in the preparation process of ruthenium-based materials prevents the formation of undesirable ruthenium oxides. The nano-sized materials prepared during the experiment did not exhibit loss of their catalytic properties after being exposed to air for several weeks. 4 refs., 2 figs.

  5. Propensity score modelling in observational studies using dimension reduction methods.

    Science.gov (United States)

    Ghosh, Debashis

    2011-07-01

    Conditional independence assumptions are very important in causal inference modelling as well as in dimension reduction methodologies. These are two very strikingly different statistical literatures, and we study links between the two in this article. The concept of covariate sufficiency plays an important role, and we provide theoretical justification when dimension reduction and partial least squares methods will allow for valid causal inference to be performed. The methods are illustrated with application to a medical study and to simulated data.

  6. Same-Day Surgery Preparation: Reduction of Pediatric Patient Arousal and Distress through Participant Modeling.

    Science.gov (United States)

    Faust, Jan; And Others

    1991-01-01

    Children (n=26) were exposed to one of three surgery preparatory conditions: participant modeling alone, participant modeling with mother, and standard procedure control. Children exposed to modeling alone had significant reductions in physiological arousal after treatment compared to other groups. Both modeling groups exhibited significantly…

  7. Study on preparation and application performance of blue sky rare earth light storage and emission material

    Institute of Scientific and Technical Information of China (English)

    ZHOU; Shao-hui; NI; Hai-yong; HUANG; Zhao-hui; LI; Xu-bo; DING; Jian-hong; ZHANG; Zhen

    2005-01-01

    Under reduction atmosphere, a blue sky rare earth silicate light storage and emission material was prepared by high temperature solid phase synthesis. The best constituent ratio of this material was determined through orthogonal experiment, and its excitation and emission spectra and X-ray diffraction patterns were measured. And a comparative study was conducted on its application properties.

  8. Comparative study on classification power of the attributes and reducts

    Directory of Open Access Journals (Sweden)

    Nilesh Mahajan

    2015-04-01

    Full Text Available In rough set theory, reduct are those attributes which are important and are able to represent the whole range of attributes. They show up the important features of database. In the present study of educational data mining, we have used the reduct of the rough set theory to find out the important features of a particular course work. The features of course work are the subjects taught in that course work. We conclude in this paper that if all the subjects are taken, the classificatory power remains same as in case where only the reduct is taken.

  9. Effect of Preparation Condition of TiO Film and Experimental Condition on CO Reduction Performance of TiO Photocatalyst Membrane Reactor

    Directory of Open Access Journals (Sweden)

    Akira Nishimura

    2011-01-01

    Full Text Available It was previously reported that CO2 could be reduced into CO, CH4, and so forth, which can be used as fuels, by TiO2 as the photocatalyst under UV radiation. To increase the concentration of fuel and improve CO2 reduction performance on TiO2 photocatalyst, a membrane reactor composed of TiO2 and gas separation membrane prepared by sol-gel and dip-coating method has been built. Factors such as rising speed (RS in the dip-coating process and the timing and amount of water injected in the membrane reactor in CO2 reduction experiment have been investigated. As a result, the largest amount of TiO2 film is obtained for RS=0.66 mm/s among various RS conditions investigated in this study. According to CO2 reduction experiment by gas circulation type reactor, too much water which cannot be consumed in CO2 reduction process would not help improving the CO2 reduction performance.

  10. Silver nanoparticles prepared by chemical reduction-protection method, and their application in electrically conductive silver nanopaste

    Energy Technology Data Exchange (ETDEWEB)

    Liu Jianguo, E-mail: ljg712@yahoo.com.c [Wuhan National Laboratory for Optoelectronics, College of Optoelectronics Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Li Xiangyou; Zeng Xiaoyan [Wuhan National Laboratory for Optoelectronics, College of Optoelectronics Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China)

    2010-04-02

    Ag nanoparticles were prepared in a water-phase system with a mixture of silver-ammonia complex, sodium borohydride, and lauric acid according to molar feed ratio of approximately 6:3:1. The mechanism of preparation and separation by chemical reduction-protection method was explored. The as-synthesized Ag nanoparticles were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV-vis spectroscopy, respectively. It was found that the size of high purity Ag particles was ranging from 30 to 50 nm with slight agglomeration. In addition, the as-synthesized wet Ag nanoparticles were dispersed stably in organic vehicle to formulate electrically conductive nanopaste. Upon direct-written and sintered, the array pattern of the nanopaste with the resolution of about 30 {mu}m was achieved with the electrical resistivity in the order of magnitude of 10{sup -5} {Omega} cm.

  11. PREPARATION OF Co50Ni50 ULTRAFINES BY CO-REDUCTION OF SOLUTION IN PRESENCE OF POLYMER

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The reduction reaction of aqueous Co2+ -hydrazine, which cannot be conducted under the common condition, is carried out by using both of low-temperature heating and stirring. Metallic ultrafines are prepared by this method. In the presence of polyvinyl alcohol (PVA), it is absorbed on the surface of particles of the product and forms a structure of complex particle, which is favorable to the stability of the powder size distribution. Co50Ni50 magnetic alloy ultrafines with fcc-cubic system can also be prepared from Co2+ -Ni2 +hybrid solution by the same method in the presence of PVA. The effect of PVA amount on the particle size and the stability of Co50Ni50 alloy ultrafines are emphatically discussed.

  12. Preparation of N-doped graphene by reduction of graphene oxide with mixed microbial system and its haemocompatibility.

    Science.gov (United States)

    Fan, Mengmeng; Zhu, Chunlin; Feng, Zhang-Qi; Yang, Jiazhi; Liu, Lin; Sun, Dongping

    2014-05-07

    A steady, effective and environment friendly method of introducing nitrogen into graphene is by microbial reduction of graphene oxide with mixed microorganisms from the anode chamber of microbial fuel cells (MFC). Using this method, N-doped graphene is easily obtained under mild conditions and by simple treatment processes, with the N/C ratio reaching 8.14%. Various characterizations demonstrate that the as-prepared N-doped graphene has excellent properties and is comparable with, and in some aspects, even better than, pristine graphene (containing only elemental C) prepared by chemical methods. The N-doped graphene (mainly substitution of C in the plane of the graphene sheet) with uniform distribution of N was haemocompatible, nontoxic, and water-dispersible, all of which are desirable properties for biomaterials and attributable to a synergetic metabolic effect of mixed microorganisms.

  13. Hydrogenation of Furfural to Furfuryl Alcohol over Co-B Amorphous Catalysts Prepared by Chemical Reduction in Variable Media

    Institute of Scientific and Technical Information of China (English)

    LI, Hui; CHAI, Wei-Mei; LUO, Hong-Shan; LI, He-Xing

    2006-01-01

    Five Co-B amorphous alloy catalysts were prepared by chemical reduction in different media, including pure water and pure ethanol as well as the mixture of ethanol and water with variable ethanol content. Their catalytic properties were evaluated using liquid phase furfural hydrogenation to furfuryl alcohol as the probe reaction. It was found that the reaction media had no significant influence on either the amorphous structure of the Co-B catalyst or the electronic interaction between metallic Co and alloying B. This could successfully account for the fact that all the as-prepared Co-B catalysts exhibited almost the same selectivity to furfuryl alcohol and the same activity per surface area ( RSH ), which could be considered as the intrinsic activity, since the nature of active sites remained unchanged. However, the activity per gram of Co ( RmH ) of the as-prepared Co-B catalysts increased rapidly when the ethanol content in the water-ethanol mixture used as the reaction medium for catalyst preparation increased. This could be attributed to the rapid increase in the surface area possibly owing to the presence of more oxidized boron species which could serve as a support for dispersing the Co-B amorphous alloy particles.

  14. Reduction of Tb4+ions in luminescent Y2O3:Tb nanorods prepared by microwave hydrothermal method

    Institute of Scientific and Technical Information of China (English)

    Jarosaw Kaszewski; Bartomiej S Witkowski; ukasz Wachnicki; Hanka Przybyliska; Bolesaw Kozankiewicz; Ewa Mijowska; Marek Godlewski

    2016-01-01

    Terbium doped yttrium oxide was prepared with the microwave hydrothermal method. The Y2O3:Tb nanomaterial crystal-lized as needle-like grains. Bright luminescence in the green region was observed. Significant luminescence intensity increase was obtained after thermal treatment. Reduction of terbium ions was observed after heating in the air atmosphere. Tb4+ions were found to be stabilized by crystal impurities. Hydroxyl species were found to have impact on vacancies elimination. The terbium ions were used as optical and magnetic indicator of the material properties.

  15. The Preparation of an Ultrastable Mesoporous Cr(III)-MOF via Reductive Labilization

    Science.gov (United States)

    2015-09-02

    III)- MOF via reductive labilization† Xizhen Lian,a Dawei Feng,a Ying-Pin Chen,ab Tian-Fu Liu,a Xuan Wanga and Hong-Cai Zhou*ab Kinetic labilization of...functionalities, metal– organic frameworks ( MOFs ) have demonstrated promising applications in gas storage, separation, catalysis, guest moiety immobilization...the chemical robustness of the framework by a redox reaction.7 Based on the Hard and So Acid and Base (HSAB) prin- ciple,28 chemically robust MOFs

  16. Experimental study of drag reduction in flumes and spillway tunnels

    Institute of Scientific and Technical Information of China (English)

    Ying-kui WANG; Chun-bo JIANG

    2010-01-01

    Experiments in an open flume model and spillway tunnel model were carried out using drag reduction techniques.Two drag reduction techniques were adopted in the experiments:polymer addition and coating.The drag reduction effect of a polyacrylamide(PAM)solution and dimethyl silicone oil coating were studied in the flume model experiments,and the results were analyzed.Experiments were then carried out with a model of the Xiluodu Hydropower Station,the second largest dam in China.In order to reduce the resistance,the spillway tunnels were internally coated with dimethyl silicone oil.This is the first time that these drag reduction techniques have been applied to so large a hydraulic model.The experimental results show that the coating technique can effectively increase flood discharge.The outlet velocity and the jet trajectory distance are also increased,which enhances the energy dissipation of the spillway tunnel.

  17. Studies on catalytic reduction of nitrate in groundwater

    Institute of Scientific and Technical Information of China (English)

    GENG Bing; ZHU Yanfang; JIN Zhaohui; LI Tielong; KANG Haiyan; WANG Shuaima

    2007-01-01

    Catalytic reduction of nitrate in groundwater by sodium formate over the catalyst was investigated.Pd-Cu/γ-Al2O3 catalyst was prepared by impregnation and characterized by brunauer-emmett-teller (BET),inductive coupled plasma (ICP),X-ray diffraction (XRD),transmission electron microscopy (TEM) and energy dispersive X-ray (EDX).It was found that total nitrogen was effectively removed from the nitrate solution (100 mg/L) and the removal efficiency was 87%.The catalytic activity was affected by pH,catalyst amount used,concentration of sodium formate,and initial concentration of nitrate.As sodium formate was used as reductant,precise control in the initial pH was needed.Excessively high or low initial pH (7.0 or 3.0) reduced catalytic activity.At initial pH of 4.5,catalytic activity was enhanced by reducing the amount of catalyst,while concentrations of sodium formate increased with a considerable decrease in N2 selectivity.In which case,catalytic reduction followed the first order kinetics.

  18. PREPARATION OF WC-Co POWDER BY DIRECT REDUCTION AND CARBONIZATION

    Institute of Scientific and Technical Information of China (English)

    Zhonglai Yi; Gangqin Shao; Xinglong Duan; Peng Sun; Xiaoliang Shi; Zhen Xiong; Jingkun Guo

    2005-01-01

    A new approach to produce superfine WC-Co powder by direct reduction and carbonization is proposed.Water-soluble salts containing W and Co were used as raw materials. Tungsten and cobalt oxide powder (CoWO4/WO3)was first formed by a spray-pyrolysis technique, which was then mixed with carbon black and converted to WC-Co composite powder at 950℃ for 4 h in N2 atmosphere. The resulting powder has a particle size of 100-300 nm.

  19. An automatic tooth preparation technique: A preliminary study

    Science.gov (United States)

    Yuan, Fusong; Wang, Yong; Zhang, Yaopeng; Sun, Yuchun; Wang, Dangxiao; Lyu, Peijun

    2016-04-01

    The aim of this study is to validate the feasibility and accuracy of a new automatic tooth preparation technique in dental healthcare. An automatic tooth preparation robotic device with three-dimensional motion planning software was developed, which controlled an ultra-short pulse laser (USPL) beam (wavelength 1,064 nm, pulse width 15 ps, output power 30 W, and repeat frequency rate 100 kHz) to complete the tooth preparation process. A total of 15 freshly extracted human intact first molars were collected and fixed into a phantom head, and the target preparation shapes of these molars were designed using customised computer-aided design (CAD) software. The accuracy of tooth preparation was evaluated using the Geomagic Studio and Imageware software, and the preparing time of each tooth was recorded. Compared with the target preparation shape, the average shape error of the 15 prepared molars was 0.05–0.17 mm, the preparation depth error of the occlusal surface was approximately 0.097 mm, and the error of the convergence angle was approximately 1.0°. The average preparation time was 17 minutes. These results validated the accuracy and feasibility of the automatic tooth preparation technique.

  20. Searching for magnetism in hydrogenated graphene: using highly hydrogenated graphene prepared via Birch reduction of graphite oxides.

    Science.gov (United States)

    Eng, Alex Yong Sheng; Poh, Hwee Ling; Šaněk, Filip; Maryško, Miroslav; Matějková, Stanislava; Sofer, Zdeněk; Pumera, Martin

    2013-07-23

    Fully hydrogenated graphene (graphane) and partially hydrogenated graphene materials are expected to possess various fundamentally different properties from graphene. We have prepared highly hydrogenated graphene containing 5% wt of hydrogen via Birch reduction of graphite oxide using elemental sodium in liquid NH3 as electron donor and methanol as proton donor in the reduction. We also investigate the influence of preparation method of graphite oxide, such as the Staudenmaier, Hofmann or Hummers methods on the hydrogenation rate. A control experiment involving NaNH2 instead of elemental Na was also performed. The materials were characterized in detail by electron microscopy, infrared spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy both at room and low temperatures, X-ray fluorescence spectroscopy, inductively coupled plasma optical emission spectroscopy, combustible elemental analysis and electrical resistivity measurements. Magnetic measurements are provided of bulk quantities of highly hydrogenated graphene. In the whole temperature range up to room temperature, the hydrogenated graphene exhibits a weak ferromagnetism in addition to a contribution proportional to field that is caused not only by diamagnetism but also likely by an antiferromagnetic influence. The origin of the magnetism is also determined to arise from the hydrogenated graphene itself, and not as a result of any metallic impurities.

  1. Preparation of Pt–Ru/C as an Oxygen-Reduction Electrocatalyst in Microbial Fuel Cells for Wastewater Treatment

    Directory of Open Access Journals (Sweden)

    Gaixiu Yang

    2016-09-01

    Full Text Available Carbon-supported Pt–Ru alloys with a Pt/Ru ratio of 1:1 were prepared by NaBH4 reduction at room temperature. X-ray diffraction (XRD measurements indicate that the as-prepared Pt–Ru nanoparticles had a face-centered cubic (fcc structure. X-ray photoelectron spectroscopy (XPS analyses demonstrate that alloying with Ru can decrease the 4f electron density of Pt, which results in a positive binding energy shift of 0.2 eV for the Pt 4f peaks. The catalytic properties of the synthesized Pt–Ru alloy catalysts were compared with those of commercial Pt/C catalysts by linear sweep voltammetry (LSV. The results show that the mass activity of the oxygen reduction reaction (ORR is enhanced by 2.3 times as much mass activity of Pt relative to the commercial Pt/C catalyst. Single-chambered microbial fuel cell tests also confirm that the Pt–Ru alloys as cathode catalysts have better performance than that of commercial Pt/C catalysts.

  2. On the Preparation of Nickel Nanoparticles by Chemical Reduction Method: X-ray Absorption Spectroscopy

    Directory of Open Access Journals (Sweden)

    Liang-Hsing CHOU

    2016-05-01

    Full Text Available Nickel nanoparticles were synthesized by the chemical reduction of NiCl2 with N2H4 under controlled pH environment. During nucleation, polyvinyl pyrrolidone (PVP was added as the protective agents for preventing the agglomeration of metal clusters. Color of the solution changed from green to blue during the reaction period. X-Ray Adsorption Spectroscopy (XAS, X-Ray Diffraction (XRD, and Transmission Electron Microscopy (TEM analytical methods were used to characterize the product. XAS analysis showed that the reduction reaction occurred within 5 minutes after the addition of N2H4. The length of Ni-Ni bond was 2.59 nm. The results of XRD analysis of the three cases with pH ranging from 11.0 to 13.0 suggest that the optimum pH value for the reaction appeared to be 12.0. The average particle size was 20 – 50 nm under this condition.DOI: http://dx.doi.org/10.5755/j01.ms.22.2.12921

  3. Zirconium nanoparticles prepared by the reduction of zirconium oxide using the RAPET method

    Directory of Open Access Journals (Sweden)

    Michal Eshed

    2011-04-01

    Full Text Available The aim of the current work is the synthesis and characterization of metallic Zr nanoparticles. The preparation is carried out by using the RAPET method (Reaction under Autogenic Pressure at Elevated Temperatures developed in our lab. The RAPET reaction of commercial ZrO2 with Mg powder was carried out in a closed stainless steel cell, at 750 °C. On completion of the reaction, the additionally formed MgO is removed by treatment with acid. The characterization of the product was performed by XRD, X-ray absorption spectroscopy, SEM, TEM and elemental analysis. The XRD pattern reveals that the product is composed of pure metallic zirconium, without any traces of the MgO by-product.

  4. New preparation of fish material for interlaboratory study on PFCs

    NARCIS (Netherlands)

    Korytar, P.; Lohman, M.; Kwadijk, C.J.A.F.; Barneveld, van E.

    2007-01-01

    The Institute for Environmental Studies, Vrije Universiteit (IVM) has requested Wageningen IMARES to prepare a new fish material for use in the interlaboratory performance study on analysis of perfluorinated compounds (PFCs) due to the low amount of contaminants in the previously prepared material.

  5. Au(III)-CTAB reduction by ascorbic acid: preparation and characterization of gold nanoparticles.

    Science.gov (United States)

    Khan, Zaheer; Singh, Taruna; Hussain, Javed Ijaz; Hashmi, Athar Adil

    2013-04-01

    Upon addition of tetrachloroauric(III) (HAuCl(4)) to a solution of cetyltrimethylammonium bromide (CTAB), a perfect transparent yellow colored and yellowish-precipitate appears within the time of mixing, indicating the formation of a complex between HAuCl(4) and CTAB. Morphology of gold nanoparticles in situ via chemical reduction of title reaction has been determined by using conventional techniques. The position and shape of the surface plasmon resonance (SRP) band strongly depends on the [ascorbic acid], [HAuCl(4)], [CTAB] and mixing ratio of the reactants. Sub-, post- and dilution-micellar effects are accountable to the aggregation and/or adsorption of gold nanoparticles onto the surface of CTAB. The morphology of particles was altered by changing the [reactants] as well as [CTAB]. A mechanism of nanoparticle formation has been proposed comprising different steps of particle growth.

  6. FAU分子筛封装Co(Salen)配合物复合催化剂的制备及其对氧还原电催化活性的研究%Study on preparation and electrocatalytic activity of Faujasite Zeolites encapsulated Co(Salen) complex catalysts on oxygen reduction

    Institute of Scientific and Technical Information of China (English)

    马飞; 张晶; 王文洋; 李瑞丰; 张蓉

    2013-01-01

    Zeolite Y,X and LSX encapsulated Co(Salen) complexes ( Co ( Salen)/Z) are prepared by flexible ligand method and characterized by FT-IR,UV-vis DRS and XRD. With these hybrid catalysts as modifier, the zeolite modified glassy carbon electrodes( Co( Salen)/Z( Z = Y,X, LSX)/GCE) are prepared by zeolite/polymer step-by-step coating and shows good electro-catalytical activity on oxygen reduction ( ORR). The electrochemical behavior and electro-catalytic activities of the Co(Salen)/Z(Z = Y,X, LSX)/GCE are studied using cyclic voltammetry (CV) in pH 6.86 buffer solution. The results show that it is Co( Salen) not Co2+ that is the electrocatalytic active centre of ORR in the pH 6. 86 buffer solution. The ratio of SiO2 :Al2 O3 of zeolites encapsulating Co (Salen) complex is of great influence on their electrocatalytic activity of Co(Salen) . The higher ratio of SiO2: A12O3 ,the better the electrocatalytic activity. The order of their electrocatalytic activity: Co( Salen)/LSX < Co( Salen)/X < Co( Salen)/Y.%运用自由配体法制备了不同硅铝比的FAU沸石分子筛(记作Z:包括高硅Y型、13X型和低硅X型(LSX))封装Co(Salen)配合物的复合材料,FTIR、UV-vis DRS、XRD表征表明配合物Co(Salen)被植入分子筛中形成复合催化剂(记作:Co(Salen)/Z).采用分子筛/聚合物分步涂覆法制备了固载Co(Salen)的分子筛修饰电极(记作:Co(Salen)/Z(Z=Y,X,LSX)/GCE).以循环伏安法(CV)研究了Co(Salen)/Z(Z=Y,X,LSX)/GCE修饰电极的电化学行为和电催化氧还原的催化活性.结果表明,Co(Salen)/Z(Z=Y,X,LSX)/GCE修饰电极电催化氧还原(ORR)的催化活性成分是Co(Salen),而且该Co(Salen)配合物对ORR的电催化活性受载体沸石分子筛骨架硅铝比的影响较大.对于硅铝比分别是2.O、2.5和5.8的LSX、X、Y型沸石分子筛而言,由硅铝较大的NaY所合成的电催化剂Co(Salen)/Y/GCF催化活性最高,且他们的电催化活性顺序为:Co(Salen)/Y> Co(Salen)/X> Co(Salen)/LSX.

  7. Drug silica nanocomposite: preparation, characterization and skin permeation studies.

    Science.gov (United States)

    Pilloni, Martina; Ennas, Guido; Casu, Mariano; Fadda, Anna Maria; Frongia, Francesca; Marongiu, Francesca; Sanna, Roberta; Scano, Alessandra; Valenti, Donatella; Sinico, Chiara

    2013-01-01

    The aim of this work was to evaluate silica nanocomposites as topical drug delivery systems for the model drug, caffeine. Preparation, characterization, and skin permeation properties of caffeine-silica nanocomposites are described. Caffeine was loaded into the nanocomposites by grinding the drug with mesoporous silica in a ball mill up to 10 h and the efficiency of the process was studied by XRPD. Formulations were characterized by several methods that include FTIR, XRPD, SEM and TEM. The successful loading of caffeine was demonstrated by XRPD and FTIR. Morphology was studied by SEM that showed particle size reduction while TEM demonstrated formation of both core-shell and multilayered caffeine-silica structures. Solid-state NMR spectra excluded chemical interactions between caffeine and silica matrix, thus confirming that no solid state reactions occurred during the grinding process. Influence of drug inclusion in silica nanocomposite on the in vitro caffeine diffusion into and through the skin was investigated in comparison with a caffeine gel formulation (reference), using newborn pig skin and vertical Franz diffusion cells. Results from the in vitro skin permeation experiments showed that inclusion into the nanocomposite reduced and delayed caffeine permeation from the silica nanocomposite in comparison with the reference, independently from the amount of the tested formulation.

  8. Remote fabrication and irradiation test of recycled nuclear fuel prepared by the oxidation and reduction of spent oxide fuel

    Science.gov (United States)

    Jin Ryu, Ho; Chan Song, Kee; Il Park, Geun; Won Lee, Jung; Seung Yang, Myung

    2005-02-01

    A direct dry recycling process was developed in order to reuse spent pressurized light water reactor (LWR) nuclear fuel in CANDU reactors without the separation of sensitive nuclear materials such as plutonium. The benefits of the dry recycling process are the saving of uranium resources and the reduction of spent fuel accumulation as well as a higher proliferation resistance. In the process of direct dry recycling, fuel pellets separated from spent LWR fuel rods are oxidized from UO2 to U3O8 at 500 °C in an air atmosphere and reduced into UO2 at 700 °C in a hydrogen atmosphere, which is called OREOX (oxidation and reduction of oxide fuel). The pellets are pulverized during the oxidation and reduction processes due to the phase transformation between cubic UO2 and orthorhombic U3O8. Using the oxide powder prepared from the OREOX process, the compaction and sintering processes are performed in a remote manner in a shielded hot cell due to the high radioactivity of the spent fuel. Most of the fission gas and volatile fission products are removed during the OREOX and sintering processes. The mini-elements fabricated by the direct dry recycling process are irradiated in the HANARO research reactor for the performance evaluation of the recycled fuel pellets. Post-irradiation examination of the irradiated fuel showed that microstructural evolution and fission gas release behavior of the dry-recycled fuel were similar to high burnup UO2 fuel.

  9. [Study on the appropriate parameters of automatic full crown tooth preparation for dental tooth preparation robot].

    Science.gov (United States)

    Yuan, F S; Wang, Y; Zhang, Y P; Sun, Y C; Wang, D X; Lyu, P J

    2017-05-09

    Objective: To further study the most suitable parameters for automatic full crown preparation using oral clinical micro robot. Its purpose is to improve the quality of automated tooth preparing for the system and to lay the foundation for clinical application. Methods: Twenty selected artificial resin teeth were used as sample teeth. The micro robot automatic tooth preparation system was used in dental clinic to control the picosecond laser beam to complete two dimensional cutting on the resin tooth sample according to the motion planning path. Using the laser scanning measuring microscope, each layer of cutting depth values was obtained and the average value was calculated. The monolayer cutting depth was determined. The three-dimensional (3D) data of the target resin teeth was obtained using internal scanner, and the CAD data of full-crown tooth preparation was designed by CAD self-develged software. According to the depth of the single layer, 11 complete resin teeth in phantom head were automatically prepared by the robot controlling the laser focused spot in accordance with the layer-cutting way. And the accuracy of resin tooth preparation was evaluated with the software. Using the same method, monolayer cutting depth parameter for cutting dental hard tissue was obtained. Then 15 extracted mandibular and maxillary first molars went through automatic full crown tooth preparation. And the 3D data of tooth preparations were obtained with intra oral scanner. The software was used to evaluate the accuracy of tooth preparation. Results: The results indicated that the single cutting depth of cutting resin teeth and in vitro teeth by picosecond laser were (60.0±2.6) and (45.0±3.6) μm, respectively. Using the tooth preparation robot, 11 artificial resin teeth and 15 complete natural teeth were automatically prepared, and the average time were (13.0±0.7), (17.0±1.8) min respectively. Through software evaluation, the average preparation depth of the occlusal surface

  10. Microfluidic platform for studying the electrochemical reduction of carbon dioxide

    Science.gov (United States)

    Whipple, Devin Talmage

    Diminishing supplies of conventional energy sources and growing concern over greenhouse gas emissions present significant challenges to supplying the world's rapidly increasing demand for energy. The electrochemical reduction of carbon dioxide has the potential to address many of these issues by providing a means of storing electricity in chemical form. Storing electrical energy as chemicals is beneficial for leveling the output of clean, but intermittent renewable energy sources such as wind and solar. Electrical energy stored as chemicals can also be used as carbon neutral fuels for portable applications allowing petroleum derived fuels in the transportation sector to be replaced by more environmentally friendly energy sources. However, to be a viable technology, the electrochemical reduction of carbon dioxide needs to have both high current densities and energetic efficiencies (Chapter 1). Although many researchers have studied the electrochemical reduction of CO2 including parameters such as catalysts, electrolytes and temperature, further investigation is needed to improve the understanding of this process and optimize the performance (Chapter 2). This dissertation reports the development and validation of a microfluidic reactor for the electrochemical reduction of CO2 (Chapter 3). The design uses a flowing liquid electrolyte instead of the typical polymer electrolyte membrane. In addition to other benefits, this flowing electrolyte gives the reactor great flexibility, allowing independent analysis of each electrode and the testing of a wide variety of conditions. In this work, the microfluidic reactor has been used in the following areas: • Comparison of different metal catalysts for the reduction of CO2 to formic acid and carbon monoxide (Chapter 4). • Investigation of the effects of the electrolyte pH on the reduction of CO2 to formic acid and carbon monoxide (Chapter 5). • Study of amine based electrolytes for lowering the overpotentials for CO2

  11. Preparation and characterization of nano structured Ba2SnO4 as a novel photocatalyst material for the chromate reduction

    Science.gov (United States)

    Omeiri, S.; Allalou, N.; Rekhila, G.; Bessekhouad, Y.; Trari, M.

    2013-11-01

    The photo-electrochemical properties of the layered perovskite Ba2SnO4, prepared by nitrate route are reported for the first time. The oxide exhibits a direct optical transition at 2.98 eV, attributed to the charge transfer O2-: 2p → Sn4+: 5s and possesses a chemical stability over the whole pH range. The Mott Schottky plot in acidic medium is characteristic of n type conductivity with a flat band potential E fb of -0.84 V SCE and an electron density N D of 1.14 × 1017 cm-3. The electrochemical impedance spectroscopy reveals the bulk and grain boundaries contributions. Ba2SnO4 is of interest for the environmental protection. At pH 2.5, its conduction band (CB, -0.86 V SCE) is below the HCrO4 - level, yielding a spontaneous reduction to Cr3+ under UV light. The reduction is optimized with respect to the Cr(VI) concentration. The photo reduction follows a pseudo-first-order kinetic and the data fit well the Langmuir-Hinshelwood (L-H) model with an apparent rate constant of 0.18 h-1 for an initial concentration of 50 ppm. The chromate reduction under solar light is studied under optimized conditions. In presence of oxalic acid, 73 % of initial concentration disappears after ~2 h of irradiation.

  12. Preparation of silver tin oxide powders by hydrothermal reduction and crystallization

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Silver tin oxide composite powders were synthesized by the hydrothermal method with a silver ammine solution and a Na2SnO3 solution as raw marrials. H2C2O4 was used as the co-precipitator of silver ions and tin ions. The co-precipitation conditions were investigated. The results show that the co-precipitate of Ag2C2O4 and Sn(OH)4 is available when the pH value of the solution is 4.27-8.36. Using the obtained precipitate as precursor, the reduction of Ag+ and the crystallization of tin oxide were carried out simultaneonsly by the hydrothermal method and silver tin oxide composite powders were obtained. The composite powders were characterized by X-ray diffraction (XRD) analysis, scanning electron microscope (SEM), and energy spectrum analysis. The results show that the silver tin oxide composite powders are small with a diameter of about 2 μm and with homogeneous distribution of tin.

  13. Carbohydrazide-dependent reductant for preparing nitrogen-doped graphene hydrogels as electrode materials in supercapacitor

    Science.gov (United States)

    Jiang, Man; Xing, Ling-Bao; Zhang, Jing-Li; Hou, Shu-Fen; Zhou, Jin; Si, Weijiang; Cui, Hongyou; Zhuo, Shuping

    2016-04-01

    Three-dimensional (3D) nitrogen-doped graphene hydrogels (NGHs) are designed and synthesized in an efficient and fast way by using a strong reductant of carbohydrazide as reducing and doping agent in an aqueous solution of graphene oxide (GO). The transformation of GO suspension to the hydrogels can be completed in 1 h, which can be confirmed by X-ray powder diffraction (XRD), Raman spectroscopy, and Fourier transform infrared spectroscopy (FT-IR). With adding different amounts of carbohydrazide, the obtained NGHs behave different doping of N and unlike performances in supercapacitors, which can be demonstrated by elemental analysis and X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), N2 sorption experiments, and electrochemical measurements, respectively. According to the network architectures, the NGHs all exhibited high specific capacitance, NGHs-1, NGHs-2, NGHs-5 and NGHs-10 showed specific capacitance at 167.7, 156.8, 140.4 and 119.3 F g-1 at 1 A g-1 in KOH electrolyte. The specific capacitance can still be maintained for 80.5, 79.5, 80.3 and 78.6% with an increase of the discharging current density of 10 A g-1, respectively. More interestingly, the NGHs-1 based supercapacitor also exhibited good electrochemical stability and high degree of reversibility in the long-term cycling test (81.5% retention after 4000 cycles).

  14. Case Study – Idling Reduction Technologies for Emergency Service Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Laughlin, Michael [Argonne National Lab. (ANL), Argonne, IL (United States); Owens, Russell J. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-01-01

    This case study explores the use of idle reduction technologies (IRTs) on emergency service vehicles in police, fire, and ambulance applications. Various commercially available IRT systems and approaches can decrease, or ultimately eliminate, engine idling. Fleets will thus save money on fuel, and will also decrease their criteria pollutant emissions, greenhouse gas emissions, and noise.

  15. Quantum chemical study on asymmetric catalysis reduction of imine

    Institute of Scientific and Technical Information of China (English)

    LI; Ming; (李明); TIAN; Anmin; (田安民)

    2003-01-01

    The quantum chemical method is employed to study the enantioselective reduction of imine with borane catalyzed by chiral oxazaborolidine. All the structures are optimized completely at the B3LYP/6-31G(d) level. The catalysis property of oxazaborolidine is notable. The reduction goes mainly through the formations of the catalyst-borane adduct, the catalyst-borane-imine adduct, and the catalyst-amidoborane adduct and the dissociation of the catalyst-amidoborane adduct with the regeneration of the catalyst. The controlling step for the reduction is the dissociation of the catalyst-amidoborane adduct. The main reduced product predicted theoretically is (R )-sec- ondary amine, which is in agreement with the experiment.

  16. Comparative study of synthesis and reduction methods for graphene oxide

    KAUST Repository

    Alazmi, Amira

    2016-05-14

    Graphene oxide (GO) and reduced graphene oxide (rGO) have congregated much interest as promising active materials for a variety of applications such as electrodes for supercapacitors. Yet, partially given the absence of comparative studies in synthesis methodologies, a lack of understanding persists on how to best tailor these materials. In this work, the effect of using different graphene oxidation-reduction strategies in the structure and chemistry of rGOs is systematically discussed. Two of the most popular oxidation routes in the literature were used to obtain GO. Subsequently, two sets of rGO powders were synthesised employing three different reduction routes, totalling six separate products. It is shown that the extension of the structural rearrangement in rGOs is not just dependent on the reduction step but also on the approach followed for the initial graphite oxidation.

  17. Preparation of cesium targets for gamma-spectroscopic studies

    Science.gov (United States)

    Bhattacharyya, S.; Basu, S. K.; Chanda, S.; Deb, P.; Eqbal, Md; Kundu, S.; Joseph, D.

    2000-11-01

    A procedure to prepare monoisotopic cesium compound targets for gamma-spectroscopic experiments is described. Using this procedure, uniform targets up to thicknesses of 0.6-1.2 mg/cm 2 were prepared and used for in-beam spectroscopic studies. The purity of the target was tested by energy dispersive X-ray fluorescence (EDXRF) measurements.

  18. Preparation and method of study of fossil diatoms

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.

    to be exercised during the preparation of the samples A method for the preparation of strewn slides is then explained A detailed procedure for the study of diatom-strewn slides under the microscope, using the "England finder", is described, and a note on diatom...

  19. In Their Words: Student Preparation and Perspectives on US Study

    Science.gov (United States)

    Sokolik, Maggie

    2015-01-01

    US universities are admitting higher percentages of international students, bringing into focus concerns with how to best support them once they are at the university. However, less attention has been paid to the preparation they undertake before matriculation. This study looks at how students are prepared before arrival and how this preparation…

  20. Preparation of Stereodefined Homoallylic Amines from the Reductive Cross-Coupling of Allylic Alcohols with Imines

    Science.gov (United States)

    Chen, Ming Z.; McLaughlin, Martin; Takahashi, Masayuki; Tarselli, Michael A.; Yang, Dexi; Umemura, Shuhei; Micalizio, Glenn C.

    2010-01-01

    Regio-, diastereo-, and enantioselective coupling reactions between imines and allylic alcohols have been developed. These coupling reactions deliver complex homoallylic amine products through a convergent C–C bond forming process that does not proceed through intermediate allylic organometallic reagents. In general, convergent coupling, by exposure of an allylic alkoxide to a preformed Ti–imine complex, occurs with allylic transposition in a predictable and stereocontrolled manner. While simple diastereoselection in these reactions is high, delivering anti-products with ≥ 20:1 selectivity, the organometallic transformation described is compatible with a diverse range of functionality and substrates (including: aliphatic and aromatic imines, allylic silanes, trisubstituted alkenes, vinyl- and aryl halides, trifluoromethyl groups, thioethers, and aromatic heterocycles). Alkene geometry of the products is a complex function of the allylic alcohol structure, and is consistent with a mechanistic proposal based on syn-carbometalation followed by syn-elimination by way of a boat-like transition state geometry. Single asymmetric coupling reactions provide a means to translate the stereochemical information of the allylic alcohol to the homoallylic amine with very high levels of fidelity, or to control diastereoselection in the coupling reactions of achiral allylic alcohols with chiral imines. Double asymmetric coupling reactions are also described that afford a unique means to control stereoselection in these complex convergent coupling processes. Finally, empirical models are proposed that are consistent with the observed stereochemical course of these coupling reactions en route to chiral homoallylic amines possessing di- or trisubstituted alkenes, and anti- or syn- relative stereochemistry at the allylic and homoallylic positions. Overall, the bond construction enabled by this Ti-mediated reductive cross-coupling is unmatched by available methods in organic

  1. Preparation, structural characterization of a novel egg-shell palladium sulfide catalyst and its application in selective reductive alkylation reaction

    Institute of Scientific and Technical Information of China (English)

    Qun Feng Zhang; Xiao Nian Li; Jia Chun Wu; Chang Su; Feng Feng; Qiao Ling Ding; Zhao Lian Yuan; Hong Wang; Lei Ma; Chun Shan Lu

    2012-01-01

    A novel egg-shell Pd-S catalyst with palladium metal as the core and a membrane of palladium sulfide as the surface has been prepared by sulphidizing Pd/C with H2S.This catalyst is effective for the reductive alkylation of p-amino diphenylamine (PADPA)and methylisobutyl ketone (MIBK) to afford N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenedianine (DBPPD) with conversion up to 99.42% and selectivity to 97.46%.Comparing with the other common palladium sulfide catalysts,the membrane of palladium sulfide on the surface and the core of palladium metal cause the Pd on the surface of the new catalyst in a lower sulfur coordination,which improves its activity.Our result indicates that this new egg-shell Pd-S/C is an efficient hydrogenation catalyst.

  2. Facile preparation of graphene-copper nanoparticle composite by in situ chemical reduction for electrochemical sensing of carbohydrates.

    Science.gov (United States)

    Chen, Qiwen; Zhang, Luyan; Chen, Gang

    2012-01-03

    A novel graphene-copper nanoparticle composite was prepared by the in situ chemical reduction of a mixture containing graphene oxide and copper(II) ions using potassium borohydride as a reductant. It was mixed with paraffin oil and packed into one end of a fused capillary to fabricate microdisc electrodes for sensing carbohydrates. The morphology and structure of the graphene-copper nanoparticle composite were investigated by scanning electron microscopy, X-ray diffraction, and Fourier transform-infrared spectroscopy. The results indicated that copper nanoparticles with an average diameter of 20.8 nm were successfully deposited on graphene nanosheets to form a well interconnected hybrid network. The analytical performance of these unique graphene-copper nanoparticle composite paste electrodes was demonstrated by sensing five carbohydrates in combination with cyclic voltammetry and capillary electrophoresis (CE). The advantages of the composite detectors include higher sensitivity, satisfactory stability, surface renewability, bulk modification, and low expense of fabrication. They should find applications in microchip CE, flowing-injection analysis, and other microfluidic analysis systems.

  3. Microwave permittivity of SiC-Al2O3 composite powder prepared by sol-gel and carbothermal reduction

    Institute of Scientific and Technical Information of China (English)

    LIU Xiao-kui; LUO Fa; ZHU Dong-mei; ZHOU Wan-cheng

    2006-01-01

    SiC-Al2O3 composite powder was prepared by sol-gel and carbothermal reduction method. The powder synthesized was characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM) to confirm the phase formation,and the thermodynamic analysis was performed systematically. Moreover,the variation of its microwave permittivity with different atomic ratio of Al/Si was investigated in the frequency range of 8.2-12.4 GHz. The results show that,the powder obtained consists of spherical particles of 300-400 nm in diameter,which are composed of SiC and Al2O3 microcrystal with the grain size of approximately 45 nm. The results of XRD accord with those of the thermodynamic analysis. It is impossible for Al atoms to dissolve in the lattice of SiC during the carbothermal reduction process. Along with the increase of atomic ratio of Al/Si in the xerogel,the amount of Al2O3 in the powder synthesized increases,which reduces both ε′,the real part of complex permittivity,and tgδ(ε″/ε′),the dissipation factor,where ε″ is the imaginary part of complex permittivity.

  4. Preparation of highly active manganese oxides supported on functionalized MWNTs for low temperature NOx reduction with NH3

    Science.gov (United States)

    Pourkhalil, Mahnaz; Moghaddam, Abdolsamad Zarringhalam; Rashidi, Alimorad; Towfighi, Jafar; Mortazavi, Yadollah

    2013-08-01

    Manganese oxide catalysts (MnOx) supported on functionalized multi-walled carbon nanotubes (FMWNTs) for low temperature selective catalytic reduction (LTSCR) of nitrogen oxides (NOx) with NH3 in the presence of excess O2 were prepared by the incipient wetness impregnation method. These catalysts were characterized by N2 adsorption, Fourier transform infrared spectroscopy (FTIR), transmission electron microscope (TEM), X-ray diffraction (XRD), thermal gravimetric analysis (TGA) and H2-temperature programmed reduction (H2-TPR) methods. The effects of reaction temperature, MnOx loading, calcination temperature and calcination time were investigated. The presence of surface nitrate species under moderate calcination conditions may play a favorable role in the LTSCR of NOx with NH3. Under the reaction conditions of 200 °C, 1 bar, NO = NH3 = 900 ppm, O2 = 5 vol%, GHSV = 30,000 h-1 and 12 wt% MnOx, NOx conversion and N2 selectivity were 97% and 99.5%, respectively. The SCR activity was reduced in the presence of 100 ppm SO2 and 2.5 vol% H2O from 97% to 92% within 6 h at 200 °C, however such an effect was shown to be reversible by exposing the catalyst to a helium flow for 2 h at 350 °C due to thermal decomposition of ammonium sulphate salts.

  5. TOEFL Preparation Courses: A Study of Washback.

    Science.gov (United States)

    Alderson, J. Charles; Hamp-Lyons, Liz

    1996-01-01

    Presents a case study of the effects of the Test of English as a Foreign Language (TOEFL) on two teachers in the same institution. The study investigates claims that the TOEFL exerts an undesirable influence on language teaching. Findings reveal that influences on what happens in class are more complex than unexamined beliefs about washback allow.…

  6. Structure and Stability of Pt-Y Alloy Particles for Oxygen Reduction Studied by Electron Microscopy

    DEFF Research Database (Denmark)

    Deiana, Davide; Wagner, Jakob Birkedal; Hansen, Thomas Willum

    2015-01-01

    Platinum-yttrium alloy nanoparticles show both a high activity and stability for the oxygen reduction reaction. The catalysts were prepared by magnetron sputter aggregation and mass filtration providing a model catalyst system with a narrow size distribution. The structure and stability...... of nanostructured Pt-Y alloy catalysts were studied using transmission electron microscopy techniques. Using elemental X-ray mapping and high-resolution electron microscopy, the specific compositional structure and distribution of the individual nanoparticles was unraveled and the stability assessed. Studying...... the catalyst after reaction and after aging tests shows the development of a core-shell type structure after being exposed to reaction conditions....

  7. Structure and Stability of Pt-Y Alloy Particles for Oxygen Reduction Studied by Electron Microscopy

    DEFF Research Database (Denmark)

    Deiana, Davide; Wagner, Jakob Birkedal; Hansen, Thomas Willum

    2015-01-01

    Platinum-yttrium alloy nanoparticles show both a high activity and stability for the oxygen reduction reaction. The catalysts were prepared by magnetron sputter aggregation and mass filtration providing a model catalyst system with a narrow size distribution. The structure and stability...... of nanostructured Pt-Y alloy catalysts were studied using transmission electron microscopy techniques. Using elemental X-ray mapping and high-resolution electron microscopy, the specific compositional structure and distribution of the individual nanoparticles was unraveled and the stability assessed. Studying...... the catalyst after reaction and after aging tests shows the development of a core-shell type structure after being exposed to reaction conditions....

  8. Field Study of Infiltration Capacity Reduction of Porous Mixture Surfaces

    Directory of Open Access Journals (Sweden)

    Luis A. Sañudo-Fontaneda

    2014-03-01

    Full Text Available Porous surfaces have been used all over the world in source control techniques to minimize flooding problems in car parks. Several studies highlighted the reduction in the infiltration capacity of porous mixture surfaces after several years of use. Therefore, it is necessary to design and develop a new methodology to quantify this reduction and to identify the hypothetical differences in permeability between zones within the same car park bay due to the influence of static loads in the parked vehicles. With this aim, nine different zones were selected in order to check this hypothesis (four points under the wheels of a standard vehicle and five points between wheels. This article presents the infiltration capacity reduction results, using the LCS permeameter, of Polymer-Modified Porous Concrete (9 bays and Porous Asphalt (9 bays surfaces in the University of Cantabria Campus parking area (Spain 5 years after their construction. Statistical analysis methodology was proposed for assessing the results. Significant differences were observed in permeability and reduction in infiltration capacity in the case of porous concrete surfaces, while no differences were found for porous asphalt depending on the measurement zone.

  9. Does carbon reduction increase sustainability? A study in wastewater treatment.

    Science.gov (United States)

    Sweetapple, Christine; Fu, Guangtao; Butler, David

    2015-12-15

    This study investigates the relationships between carbon reduction and sustainability in the context of wastewater treatment, focussing on the impacts of control adjustments, and demonstrates that reducing energy use and/or increasing energy recovery to reduce net energy can be detrimental to sustainability. Factorial sampling is used to derive 315 control options, containing two different control strategies and a range of sludge wastage flow rates and dissolved oxygen setpoints, for evaluation. For each, sustainability indicators including operational costs, net energy and multiple environmental performance measures are calculated. This enables identification of trade-offs between different components of sustainability which must be considered before implementing energy reduction measures. In particular, it is found that the impacts of energy reduction measures on sludge production and nitrogen removal must be considered, as these are worsened in the lowest energy solutions. It also demonstrates that a sufficiently large range of indicators need to be assessed to capture trade-offs present within the environmental component of sustainability. This is because no solutions provided a move towards sustainability with respect to every indicator. Lastly, it is highlighted that improving the energy balance (as may be considered an approach to achieving carbon reduction) is not a reliable means of reducing total greenhouse gas emissions.

  10. Study on air pollution reduction costs of power industry

    Energy Technology Data Exchange (ETDEWEB)

    Yun, W.C. [Korea Energy Economics Institute, Euiwang (Korea, Republic of); Kwon, O.S. [Seoul University, Seoul (Korea, Republic of)

    1998-04-01

    This study mainly treats the productivity change due to the use of low-sulfur fuel oil in the power generation sector and estimates marginal reduction cost due to air pollution as contents. For this, domestic energy use, supply and demand status and forecast of power sector are described, and the effect of the use of low-sulfur fuel oil in power generation sector was analyzed and the result was summarized. The marginal reduction cost of air pollutants in domestic power sector was estimated and the result was summarized using products distance functions. Major results can be summarized as follows. 1. Pollution control, profitability based on size and technology development are found to exert a statistically meaningful influence on a productivity change in power generation sector. Among these, pollution control by the supply of low- sulfur fuel oil is found to have both primary factors that either increase or decrease productivity. 2. The result of estimating the marginal reduction cost of domestic thermoelectric power plants using the duality of products distance function and import function shows that average marginal reduction costs for the period of 1990 {approx} 1995 are 310.6 thousands Won for SO{sub X}, 146.7 thousands Won for NO{sub X}, 15,482.3 thousands Won for TSP, and 3.8 thousands Won for CO{sub 2} in case four pollutants are all included though there may be some difference based on the assumption of model. 70 refs., 16 figs., 30 tabs.

  11. A study on reduction of copper slag from the flash furnace with the use of anthracite dust

    Directory of Open Access Journals (Sweden)

    G. Siwiec

    2014-07-01

    Full Text Available In the paper, results of a study on reduction of blister copper flash smelting slag with the use of anthracite dust are presented. The material, following proper preparation, can be used for slag processing as a substitute for currently applied coke breeze.

  12. Experimental and Modeling Study on Reduction of Hematite Pellets by Hydrogen Gas

    Science.gov (United States)

    Kazemi, Mania; Pour, Mohsen Saffari; Sichen, Du

    2017-01-01

    Gaseous reduction by hydrogen was performed for three types of hematite pellets, two from industry and one prepared in the laboratory. The reduction mechanisms of the pellets were studied based on the morphologies of the partially reduced samples. Two mechanisms were found, the mechanisms of the two types of industrial pellets being very similar. The degree of reduction was followed as a function of time for each type of pellets. On the basis of the reaction mechanism of the industrial pellets, a mathematical model was developed. As a pioneer effort, the model combined the computational fluid dynamics approach for the flow and mass transfer in the gas phase with model of gas diffusion in the solid phase as well as the description of the chemical reaction at the reaction sites. The calculation results agreed well with the experimentally obtained reduction curves. The present work also emphasized the importance of evaluation of the reduction mechanisms and the properties of different types of iron ore pellets prior to developing a process model. While the present approach has established a good foundation for the dynamic modeling of the shaft reactor, more efforts are required to accomplish a realistic process model.

  13. Experimental and Modeling Study on Reduction of Hematite Pellets by Hydrogen Gas

    Science.gov (United States)

    Kazemi, Mania; Pour, Mohsen Saffari; Sichen, Du

    2017-04-01

    Gaseous reduction by hydrogen was performed for three types of hematite pellets, two from industry and one prepared in the laboratory. The reduction mechanisms of the pellets were studied based on the morphologies of the partially reduced samples. Two mechanisms were found, the mechanisms of the two types of industrial pellets being very similar. The degree of reduction was followed as a function of time for each type of pellets. On the basis of the reaction mechanism of the industrial pellets, a mathematical model was developed. As a pioneer effort, the model combined the computational fluid dynamics approach for the flow and mass transfer in the gas phase with model of gas diffusion in the solid phase as well as the description of the chemical reaction at the reaction sites. The calculation results agreed well with the experimentally obtained reduction curves. The present work also emphasized the importance of evaluation of the reduction mechanisms and the properties of different types of iron ore pellets prior to developing a process model. While the present approach has established a good foundation for the dynamic modeling of the shaft reactor, more efforts are required to accomplish a realistic process model.

  14. Preparation and Characterization of Reduced Graphene Oxide Sheets via Water-Based Exfoliation and Reduction Methods

    OpenAIRE

    2013-01-01

    This research studied the synthesis of graphene oxide and graphene via a low-cost manufacturing method. The process started with the chemical oxidation of commercial graphite powder into graphite oxide by modified Hummer’s method, followed by the exfoliation of graphite oxide in distilled water using the ultrasound frequency from a laboratory ultrasonic bath. Finally, the oxygen functional groups on exfoliated graphite oxide or graphene oxide were eliminated by stirring in hot distilled water...

  15. Exploring paradigms of crime reduction: An empirical longitudinal study

    DEFF Research Database (Denmark)

    Soothill, University of Lancaster, Keith; Christoffersen, Mogens; Azhar, Hussain

    Using Danish registers for a 1980 birth cohort of 29,944 males with parental information and following up these cases for 24 years, the study considers four paradigms of crime reduction (parental child-rearing, structural factors around adolescence, locality and individual resources). Focusing...... more widespread benefits, but the assumed causal links need to be further explored. The use of population registers, under controlled conditions, provides an important window on criminal careers....

  16. Preparation and Characterization of Reduced Graphene Oxide Sheets via Water-Based Exfoliation and Reduction Methods

    Directory of Open Access Journals (Sweden)

    Vorrada Loryuenyong

    2013-01-01

    Full Text Available This research studied the synthesis of graphene oxide and graphene via a low-cost manufacturing method. The process started with the chemical oxidation of commercial graphite powder into graphite oxide by modified Hummer’s method, followed by the exfoliation of graphite oxide in distilled water using the ultrasound frequency from a laboratory ultrasonic bath. Finally, the oxygen functional groups on exfoliated graphite oxide or graphene oxide were eliminated by stirring in hot distilled water at 95°C, as a replacement for highly toxic and dangerously unstable hydrazine. The results assured that stirring in hot distilled water could give the product of graphene or reduced graphene oxide. The samples were characterized by FTIR, XRD, TGA, Raman spectroscopy, SEM, and TEM methods.

  17. Nanocapsular forms of preparations in preclinical studies

    Directory of Open Access Journals (Sweden)

    Ekaterina Grinevich

    2010-07-01

    Full Text Available The paper examines preclinical study of nanocapsule deliverysystem, particularly the influence of nanocapsule with a vasodilatorin the process of programmed myocardial cells death. Isosorbidedinitrate was loaded in nanocapsules. To investigate the effectnanocapsule isosorbide dinitrate on the process of apoptosis incardiomyocytes, a series of experimental works wereperformed. For this purpose, a model of coronary insufficiency in 4groups of animals were elaborated. The experimental works onlaboratory animals were conducted in accordance withrequirements of the European Convention for the protection ofvertebrate animals. The first preclinical trials showed the presenceof specific activity of obtained drugs. The basis of nanocapsularsystem was phosphatidylinositol, and the active loading substanceswere alprostadil, interferon alpha.

  18. Studies on Electrolytic preparation of Iron Copper Powders

    Directory of Open Access Journals (Sweden)

    S. V. Athvale

    1971-07-01

    Full Text Available Factors affecting the physical characteristics and chemical composition of iron-cooper powder deposits obtained by electrolysis, have been investigated. Effect of process variables such as current density, pH, temperature, time, concentration of electrolyte and agitation, has been studied over a wide range, for theoretical interest and to obtain powder deposits of a definite composition. Metallographic examination of iron-copper powder thus prepared after compacting and sintering, has revealed uniform and homogeneous dispersion of the two metals. The technique of preparation presented in this paper is a better substitute to the conventional practice of preparing binary metal powders by mixing and tumbling.

  19. Preparation of stimuli for timbre perception studies.

    Science.gov (United States)

    Labuschagne, Ilse B; Hanekom, Johan J

    2013-09-01

    Stimuli used in timbre perception studies must be controlled carefully in order to yield meaningful results. During psychoacoustic testing of individual timbre properties, (1) it must be ensured that timbre properties do not co-vary, as timbre properties are often not independent from one another, and (2) the potential influence of loudness, pitch, and perceived duration must be eliminated. A mathematical additive synthesis method is proposed which allows complete control over two spectral parameters, the spectral centroid (corresponding to brightness) and irregularity, and two temporal parameters, log rise-time (LRT) and a parameter characterizing the sustain/decay segment, while controlling for covariation in the spectral centroid and irregularity. Thirteen musical instrument sounds were synthesized. Perceptual data from six listeners indicate that variation in the four timbre properties mainly influences loudness and that perceived duration and pitch are not influenced significantly for the stimuli of longer duration (2 s) used here. Trends across instruments were found to be similar.

  20. Bayesian model reduction and empirical Bayes for group (DCM) studies.

    Science.gov (United States)

    Friston, Karl J; Litvak, Vladimir; Oswal, Ashwini; Razi, Adeel; Stephan, Klaas E; van Wijk, Bernadette C M; Ziegler, Gabriel; Zeidman, Peter

    2016-03-01

    This technical note describes some Bayesian procedures for the analysis of group studies that use nonlinear models at the first (within-subject) level - e.g., dynamic causal models - and linear models at subsequent (between-subject) levels. Its focus is on using Bayesian model reduction to finesse the inversion of multiple models of a single dataset or a single (hierarchical or empirical Bayes) model of multiple datasets. These applications of Bayesian model reduction allow one to consider parametric random effects and make inferences about group effects very efficiently (in a few seconds). We provide the relatively straightforward theoretical background to these procedures and illustrate their application using a worked example. This example uses a simulated mismatch negativity study of schizophrenia. We illustrate the robustness of Bayesian model reduction to violations of the (commonly used) Laplace assumption in dynamic causal modelling and show how its recursive application can facilitate both classical and Bayesian inference about group differences. Finally, we consider the application of these empirical Bayesian procedures to classification and prediction.

  1. Preparation of Nd-Fe-B by nitrate-citrate auto-combustion followed by the reduction-diffusion process.

    Science.gov (United States)

    Ma, Hao Xuan; Kim, Chang Woo; Kim, Dong Soo; Jeong, Ji Hun; Kim, In Ho; Kang, Young Soo

    2015-05-07

    The Nd2Fe14B alloy has been successfully synthesized by nitrate-citrate auto-combustion followed by the reduction and diffusion process with low energy consumption. H3BO3, Fe(NO3)3·9H2O, and Nd(NO3)3·6H2O were used as precursors and citric acid was used as the chelating ligand of metal ions. Ammonia water was used to adjust pH to 7. CaH2 was used as a reducing agent for the reduction and diffusion process. NdFeO3 and Fe2O3 were produced during auto-combustion of gel. The combustion process of the gel was investigated by TGA/DTA curve measurements. The phase compositions were studied by XRD measurements. The differences of the overall morphology and magnetic properties were measured by SEM, TEM and vibrating sample magnetometry (VSM) at 300 K. The comparison of the magnetic properties of the reduced samples between the pellet type and the random powder type was done with VSM and it showed better magnetic properties of the pellet type Nd2Fe14B. Making a compact pellet type sample for reduction is more efficient for solid reduction and phase transition for higher coercivity.

  2. Single crystal studies of platinum alloys for oxygen reduction electrodes

    DEFF Research Database (Denmark)

    Ulrikkeholm, Elisabeth Therese

    In this thesis the discovery, characterization and testing of new catalysts for the oxygen reduction reaction (ORR) is investigated. Experiments on sputter cleaned, polycrystalline Pt5Y and Pt5Gd crystals have shown that these alloys are excelent candidates for catalysts for the ORR. To mimic...... was performed on the samples as prepared, and after electrochemical cycling between 0.05 V and 1.0 V VS. RHE. and between 0.05 V and 1.2 V VS. RHE. Diffraction experiments carried out after the cycling to 1.0 V showed that an overlayer with crystalline order had been formed on the Y/Pt(111) sample and the Gd....../Pt(111) samples. These overlayers were slightly compressed compared to pure platinum and had a 6-fold symmetry. After cycling to 1.2 V VS. RHE. the correlation length of the overlayer on the Gd/Pt(111) sample had decreased significantly, and the overlayer on the Y/Pt(111) had disappeared completely...

  3. Fermented Papaya Preparation Restores Age-Related Reductions in Peripheral Blood Mononuclear Cell Cytolytic Activity in Tube-Fed Patients

    Science.gov (United States)

    Fujita, Yuhzo; Tsuno, Haruo; Nakayama, Jiro

    2017-01-01

    Tube-fed elderly patients are generally supplied with the same type of nutrition over long periods, resulting in an increased risk for micronutrient deficiencies. Dietary polyphenols promote immunity and have anti-inflammatory, anti-carcinogenic, and anti-oxidative properties. Carica papaya Linn. is rich in several polyphenols; however, these polyphenols are poorly absorbed from the digestive tract in their original polymerized form. Therefore, we determined the molecular components of a fermented Carica papaya Linn. preparation, as well as its effects on immunity and the composition of gut microbiota in tube-fed patients. Different doses of the fermented C. papaya L. preparation were administered to three groups of tube-fed patients for 30 days. Its effects on fecal microbiota composition and immunity were assessed by 16S rRNA gene sequencing and immune-marker analysis, respectively. The chemical composition of the fermented C. papaya L. preparation was analyzed by capillary electrophoresis- and liquid chromatography- time of flight mass spectrometry. The fermented C. papaya L. preparation restored peripheral blood mononuclear cell (PBMC) cytolytic activity; however, no other biomarkers of immunity were observed. Treatment with the preparation (9 g/day) significantly reduced the abundance of Firmicutes in the fecal microbiota. In particular, treatment reduced Clostridium scindens and Eggerthella lenta in most patients receiving 9 g/day. Chemical analysis identified low-molecular-weight phenolic acids as polyphenol metabolites; however, no polymerized, large-molecular-weight molecules were detected. Our study indicates that elderly patients who are tube-fed over the long-term have decreased PBMC cytolytic activity. In addition, low-molecular-weight polyphenol metabolites fermented from polymerized polyphenols restore PBMC cytolytic activity and modulate the composition of gut microbiota in tube-fed patients. PMID:28060858

  4. Techniques for preparing of guide planes: in vitro comparative study

    OpenAIRE

    Uemura, Eduardo Shigueyuki; Assistant Professor of the Dental Materials and Prosthesis Department of the São José dos Campos School of Dentistry of the São Paulo State University.; Silva, João Maurício; Faculdade de Odontologia de São José dos Campos - UNESP; Borges, Alexandre Luiz Souto; Assistant Professor of the Dental Materials and Prosthesis Department of the São José dos Campos School of Dentistry of the São Paulo State University.; Yamamoto, Eron Toshio Colauto; Clinical Professor of the Dental Materials and Prosthesis Department of the School of Dentistry of the 9th of July University.

    2014-01-01

    The correct parallelism of guiding planes when constructing a Removable Partial Denture not only defines the axis of insertion and removal of the prosthesis, but also limits the possible axes of movement during functioning. Therefore, the purpose of the study was to compare some techniques and the use of an intra-oral device for those preparations. Dummies were performed in a direct manner, simulating the absence of teeth 15, 45, 12 and 42. The four preparation techniques chosen were: Group 1...

  5. Preparation, properties, and some recent studies of the actinide metals

    Energy Technology Data Exchange (ETDEWEB)

    Haire, R.G.

    1985-01-01

    The actinide elements form a unique series of metals. The variation in their physial properties combined with the varying availability of the different elements offers a challenge to the preparative scientist. This article provides a brief review of selected methods used for preparing ..mu..g to kg amounts of the actinide metals and the properties of these metals. In addition, some recent studies on selected actinide metals are discussed. 62 refs.

  6. Nitrite residue and malonaldehyde reduction in dendeng--Indonesian dried meat--influenced by spices, curing methods and precooking preparation.

    Science.gov (United States)

    Suryati, T; Astawan, M; Lioe, H N; Wresdiyati, T; Usmiati, S

    2014-03-01

    This research was conducted to reduce nitrite residue and malonaldehyde (MDA) content of dendeng through modifying the formulation of spices, curing technique and precooking preparation. The result showed that spiced fried dendeng was likely to contain high total phenolics and antioxidant activity. Wet cured dendeng combined with spices containing 2.0% coriander and 10.0% garlic and preparation by soaking before frying was effective to produce dendeng that had no detected nitrite residue and low MDA. In conclusion, the spice formulas used in this study could reduce nitrite residue and MDA level of dendeng, and the treatment prior to frying, by soaking the dendeng briefly in water, lowered MDA of non-spiced dendeng, but no effect of soaking was observed in spiced samples due to the very low MDA found in the samples.

  7. Exploring paradigms of crime reduction: An empirical longitudinal study

    DEFF Research Database (Denmark)

    Soothill, University of Lancaster, Keith; Christoffersen, Mogens; Azhar, Hussain

    on offenders with first-time convictions for shoplifting (n=1,778), for violence (n=1,585) and for burglary (n=1,208), all four paradigms made a contribution to risk of first time offending for all three crimes. The counter factual analysis indicated that a focus on structural issues within a society may have......Using Danish registers for a 1980 birth cohort of 29,944 males with parental information and following up these cases for 24 years, the study considers four paradigms of crime reduction (parental child-rearing, structural factors around adolescence, locality and individual resources). Focusing...

  8. Preparation and Thermal Stability of Ultrafine Nickel Powders Containing hcp-Ni Nanocrystallites Using Liquid-Phase Reduction Method

    Science.gov (United States)

    Xia, Zhimei; Jin, Shengming; Liu, Kun

    2016-10-01

    Ultrafine nickel powders containing hexagonal close-packed nickel (hcp-Ni) nanocrystallites were prepared using liquid-phase reduction with NiC2O4, NaOH, polyvinylpyrrolidone (PVP), and ethylene glycol (EG). The nickel powders were characterized by XRD and SEM. TG analysis was used to determine the thermal stability of ultrafine nickel powders. The results showed that nickel powders with 45.1 pct of hcp-Ni nanocrystallites were synthesized under the following conditions: a reflux time of 3 hours, an NiC2O4-to-EG molar ratio of 0.01, 5 g/L PVP, and 85 g/L NaOH. SEM results illustrated that spherical particles of size 500 nm were obtained. The results of thermal stability showed that the antioxidant property at high temperature was improved with the increase of hcp-Ni content. The oxidation rate of nickel powders with 43.3 pct hcp-Ni was less than 50 pct even if the temperature was up to 873 K (600 °C).

  9. Preparation of novel composites based on hydrophilized and functionalized polyacrylonitrile membrane-immobilized NZVI for reductive transformation of metronidazole

    Science.gov (United States)

    Wang, Xiangyu; Liu, Peng; Ma, Jun; Liu, Huiling

    2017-02-01

    For the first time, hydrophilized and functionalized polyacrylonitrile (PAN) membrane was synthesized via two-stage process, addition of polyvinyl alcohol and in situ polymerization of acrylic acid (AA), and nano zero-valent iron (NZVI) was incorporated within modified membrane. The as-prepared PAA/PAN-NZVI (PPN) composites possessed superior reactivity for metronidazole (MNZ) with transformation ratio 2.03 and reaction rate 4.77 times higher than that by bare NZVI. Meanwhile, the enhanced stability and recyclability of PPN composites were maintained over repeated cycles. The major advantages of synthetic method lie in the remarkably increased loading and decreased agglomeration of NZVI. Moreover, with hydrophilized and functionalized synthesis processes of membrane, the potential risk of released iron ions was not a concern due to strong chelation of grafted carboxyl groups. Analyses of morphological characteristics (FE-SEM), chemical structure (FTIR), element valence and groups (XPS) of samples confirmed the successful graft of carboxylic acid groups and formation of a uniform iron nanoparticles coating onto PAN matrix. The reaction kinetics of MNZ with PPN composites were well-described by a two-parameter pseudo-first-order decay model with activation energy of 29.5 kJ/mol. The co-solutes except humic acid had a negligible effect on MNZ transformation. Determination of intermediates revealed that nitro reduction, N-denitration and hydroxyethyl cleavage were the main pathways for transformation of MNZ. The findings suggest that the novel composites possess huge potential for antibiotics wastewater treatment.

  10. Preparation and physicochemical properties of surfactant-free emulsions using electrolytic-reduction ion water containing lithium magnesium sodium silicate.

    Science.gov (United States)

    Okajima, Masahiro; Wada, Yuko; Hosoya, Takashi; Hino, Fumio; Kitahara, Yoshiyasu; Shimokawa, Ken-ichi; Ishii, Fumiyoshi

    2013-04-01

    Surfactant-free emulsions by adding jojoba oil, squalane, olive oil, or glyceryl trioctanoate (medium chain fatty acid triglycerides, MCT) to electrolytic-reduction ion water containing lithium magnesium sodium silicate (GE-100) were prepared, and their physiochemical properties (thixotropy, zeta potential, and mean particle diameter) were evaluated. At an oil concentration of 10%, the zeta potential was ‒22.3 ‒ ‒26.8 mV, showing no marked differences among the emulsions of various types of oil, but the mean particle diameters in the olive oil emulsion (327 nm) and MCT emulsion (295 nm) were smaller than those in the other oil emulsions (452-471 nm). In addition, measurement of the hysteresis loop area of each type of emulsion revealed extremely high thixotropy of the emulsion containing MCT at a low concentration and the olive emulsion. Based on these results, since surfactants and antiseptic agents markedly damage sensitive skin tissue such as that with atopic dermatitis, surfactant- and antiseptic-free emulsions are expected to be new bases for drugs for external use.

  11. Preparation of tri- and difluoromethylsilanes via an unusual magnesium metal-mediated reductive tri- and difluoromethylation of chlorosilanes using tri- and difluoromethyl sulfides, sulfoxides, and sulfones.

    Science.gov (United States)

    Prakash, G K Surya; Hu, Jinbo; Olah, George A

    2003-05-30

    A new and efficient method for the preparation of tri- and difluoromethylsilanes using magnesium metal-mediated reductive tri- and difluoromethylation of chlorosilanes is reported using tri- and difluoromethyl sulfides, sulfoxides, and sulfones. The byproduct of the process is diphenyl disulfide. Since phenyl trifluoromethyl sulfone, sulfoxide, and sulfide are readily prepared from trifluoromethane (CF(3)H) and diphenyl disulfide, the method can be considered to be catalytic in diphenyl disulfide for the preparation of (trifluoromethyl)trimethylsilane (TMS-CF(3)) from non-ozone-depleting trifluoromethane.

  12. Reduction of β-radiation exposure during preparation of 188Re-labelled Lipiodol for hepatocellular carcinoma treatment.

    Science.gov (United States)

    Lepareur, Nicolas; Laffont, Sophie; Ardisson, Valérie; Noiret, Nicolas; Garin, Etienne

    2012-02-01

    Rhenium-188 (188Re) is of widespread interest for treating various diseases because of its attractive physical and chemical properties. The routine preparation of therapeutic doses of 188Re-labelled tracers can result in significant radiation exposure to the operator. We studied the impact of automating the preparation of 188Re-Lipiodol on the radiochemist's exposure, as well as the importance of the model of syringe shielding. To monitor radiation exposure continuously readable electronic personal dosimeters were used. Thermoluminescence dosimeters were fixed to the probable most exposed fingers of the radiochemist during preparation of the radiotracer and during the syringing. Dose rates were measured using a Babyline. Automation of the synthesis reduced personal dose equivalents from 2.60±4.35 to 1.61±1.20 µSv/GBq [Hp(10)] and from 38.37±55.28 to 21.84±16.14 µSv/GBq [Hp(0.07)]. Dose to the extremities was also reduced (-80% for the right hand; -58% for the left one). The Lemer-Pax PSWG syringe shield led to a slightly lower dose to the hands compared with the Medisystem (1.1±0.27 vs. 1.34±0.6 mSv/GBq for the right finger). Automation of the synthesis leads to a significant decrease in radiation exposure to the operator. The Lemer-Pax PSWG syringe shield provides better hand protection than the smaller Medisystem Mediclic.

  13. Electrochemical preparation of few layer-graphene nanosheets via reduction of oriented exfoliated graphene oxide thin films in acetamide-urea-ammonium nitrate melt under ambient conditions

    Energy Technology Data Exchange (ETDEWEB)

    Dilimon, V.S.; Sampath, S., E-mail: sampath2562@gmail.co

    2011-01-31

    Electrochemical reduction of exfoliated graphene oxide, prepared from pre-exfoliated graphite, in acetamide-urea-ammonium nitrate ternary eutectic melt results in few layer-graphene thin films. Negatively charged exfoliated graphene oxide is attached to positively charged cystamine monolyer self-assembled on a gold surface. Electrochemical reduction of the oriented graphene oxide film is carried out in a room temperature, ternary molten electrolyte. The reduced film is characterized by atomic force microscopy (AFM), conductive AFM, Fourier-transform infrared spectroscopy and Raman spectroscopy. Ternary eutectic melt is found to be a suitable medium for the regulated reduction of graphene oxide to reduced graphene oxide-based sheets on conducting surfaces.

  14. Photo catalytic reduction of benzophenone on TiO{sub 2}: Effect of preparation method and reaction conditions

    Energy Technology Data Exchange (ETDEWEB)

    Albiter E, E.; Valenzuela Z, M. A.; Alfaro H, S.; Flores V, S. O.; Rios B, O.; Gonzalez A, V. J.; Cordova R, I., E-mail: mavalenz@ipn.m [IPN, Escuela Superior de Ingenieria Quimica e Industrias Extractivas, Laboratorio de Catalisis y Materiales, Zacatenco, 07738 Mexico D. F. (Mexico)

    2010-07-01

    The photo catalytic reduction of benzophenone was studied focussing on improving the yield to benzhydrol. TiO{sub 2} was synthesized by means of a hydrothermal technique. TiO{sub 2} (Degussa TiO{sub 2}-P25) was used as a reference. Catalysts were characterized by X-ray diffraction and nitrogen physisorption. The photo catalytic reduction was carried out in a batch reactor at 25 C under nitrogen atmosphere, acetonitrile as solvent and isopropanol as electron donor. A 200 W Xe-Hg lamp ({lambda}= 360 nm) was employed as irradiation source. The chemical composition of the reaction system was determined by HPLC. Structural and textural properties of the synthesized TiO{sub 2} depended on the type of acid used during sol formation step. Using HCl, a higher specific surface area and narrower pore size distribution of TiO{sub 2} was obtained in comparison with acetic acid. As expected, the photochemical reduction of benzophenone yielded benzopinacol as main product, whereas, benzhydrol is only produced in presence of TiO{sub 2} (i.e. photo catalytic route). In general, the hydrothermally synthesized catalysts were less active and with a lower yield to benzhydrol. The optimal reaction conditions to highest values of benzhydrol yield (70-80%) were found at 2 g/L (catalyst loading) and 0.5 m M of initial concentration of benzophenone, using commercial TiO{sub 2}-P25. (Author)

  15. Thermogravimetric study of the dehydration and reduction of red mud

    Science.gov (United States)

    Teplov, O. A.; Korenovskii, N. L.; Lainer, Yu. A.

    2015-01-01

    The processes of drying and reduction of red mud in the pure state and with coal additions in vacuum or in gaseous media (helium, hydrogen) have been experimentally studied by thermogravimetry using a Setaram TAG24 thermogravimetric analyzer. The minimum total weight loss (˜20%) is observed for red mud samples without additives in forevacuum, and the maximum loss (˜38%) is detected in samples with coal. It is demonstrated that, for this type of red mud with iron oxide Fe2O3, water molecules are bonded in the form of iron hydroxide Fe2O3 · 3H2O rather than goethite FeOOH. The peak of magnetite formation is observed in differential thermogravimetry (DTG) curve in the range 270-400°C. The simulation of the magnetite dehydration and formation rates under experimental conditions in the relevant temperature ranges agrees with the experimental data. A peak of wustite formation in hydrogen above ˜600°C is recorded in a DTG curve, and the removal of one-third of sodium oxide, which is likely not to be fixed into strong sodium alumosilicate, is observed in the range 800-1000°C. The peak detected in the DTG curve of the mud with charcoal in helium in the range 350-450°C is similar to the peak of hematite reduction in magnetite in a hydrogen atmosphere. The most probable source of hydrogen-containing gases in this temperature range consists of the residual hydrocarbons of charcoal. The reduction reactions of disperse iron oxides with coal proceed only at temperatures above 600°C. These processes occur in the same temperature range (600-900°C) both in forevacuum and in a helium atmosphere. It is experimentally demonstrated that sintering process occurs in the mud in the temperature range 450-850°C.

  16. Preparation of benzyl-[alpha]-D[sub 1]-alcohol by the reduction of benzaldehyde with Raney alloys in an alkaline deuterium oxide solution

    Energy Technology Data Exchange (ETDEWEB)

    Tsukinoki, Takehito; Mataka, Shuntaro; Tashiro, Masashi (Kyushu Univ. (Japan). Inst. of Advanced Material Study); Ishimoto, Keiko (Kyushu Univ. (Japan). Graduate School of Engineering Sciences); Tsuzuki, Hirohisa (Kyushu Univ., Fukuoka (Japan). Center of Advanced Instrumental Analysis)

    1993-10-01

    Benzyl-[alpha]-d[sub 1]-alcohol was prepared in high isotopic purity by the reduction of benzaldehyde with Raney Cu-Al alloy in 10% Na[sub 2]CO[sub 3]-D[sub 2]O solution using ultrasonic irradiation. (Author).

  17. Photocatalytic degradation of dye by Ag/ZnO prepared by reduction of Tollen’s reagent and the ecotoxicity of degraded products

    NARCIS (Netherlands)

    Thongrom, B; Amornpitoksuk, P; Suwanboon, S; Baltrusaitis, J.

    2014-01-01

    A heterostructure of Ag/ZnO powder was prepared by a reduction of Ag(NH3) 2 + ions in a basic solution or Tollen’s reagent. From this method, the existence of a metallic Ag coating on the ZnO surface was confirmed by transmission electron microscope and x-ray photoelectron spectroscopy. The photoca

  18. Preparation of microsomes to study Ca2+ channels.

    Science.gov (United States)

    Bezprozvanny, Ilya

    2013-11-01

    Native cerebellar microsomes are used to study the properties of native cerebellar inositol(1,4,5)-trisphosphate receptor 1 (InsP3R1) and ryanodine receptor 1 (RyanR1) Ca(2+) release channels. Additionally, microsomes prepared from Sf9 cells infected with InsP3R- or RyanR-expressing recombinant baculoviruses can be used to compare properties of different InsP3R and RyanR isoforms and to perform structure-function studies of both types of receptors. This protocol describes how to prepare ER microsomes from native cerebellar tissue or Sf9 cells infected with InsP3R- or RyanR-expressing recombinant baculoviruses for planar lipid bilayer (also called black lipid membranes or BLM) experiments. Prepared material is aliquoted and can be stored at -80°C freezer for many months before BLM experiments.

  19. Preparation of well-defined dendrimer encapsulated ruthenium nanoparticles and their evaluation in the reduction of 4-nitrophenol according to the Langmuir-Hinshelwood approach.

    Science.gov (United States)

    Antonels, Nathan Charles; Meijboom, Reinout

    2013-11-05

    This study discusses the preparation of various sized dendrimer encapsulated ruthenium nanoparticles (RuDEN) with the use of the generation 4 (G4), generation 5 (G5), and generation 6 (G6) hydroxyl-terminated poly(amidoamine) (PAMAM-OH) dendrimers as templating agents. The size of the nanoparticles ranges from 1.1 to 2.2 nm. These catalysts were fully characterized using UV/vis spectrophotometry, infrared (IR) spectroscopy, and transmission electron microscopy (TEM). The RuDEN catalysts were evaluated in the reduction of 4-nitrophenol (4NP) in the presence of sodium borohydride (BH4(-)) for various concentrations of either. The kinetic data obtained were modeled to the Langmuir-Hinshelwood equation. The model allows the relation of the apparent rate constant to the total surface area S of the nanoparticle, the kinetic constant k which is related to the rate-determining step, and the adsorption constants K(4NP) and K(BH4) for 4NP and borohydride, respectively. These parameters were calculated for each of the RuDENs, proving the Langmuir-Hinshelwood model to be suitable for the kinetic evaluation of RuDENs in the catalytic reduction of 4NP.

  20. Effect of magnesium on the aluminothermic reduction rate of zinc oxide obtained from spent alkaline battery anodes for the preparation of Al-Zn-Mg alloys

    Science.gov (United States)

    Ochoa, Rocio; Flores, Alfredo; Torres, Jesus

    2016-04-01

    The aluminothermic reduction of zinc oxide (ZnO) from alkaline battery anodes using molten Al may be a good option for the elaboration of secondary 7000-series alloys. This process is affected by the initial content of Mg within molten Al, which decreases the surface tension of the molten metal and conversely increases the wettability of ZnO particles. The effect of initial Mg concentration on the aluminothermic reduction rate of ZnO was analyzed at the following values: 0.90wt%, 1.20wt%, 4.00t%, 4.25wt%, and 4.40wt%. The ZnO particles were incorporated by mechanical agitation using a graphite paddle inside a bath of molten Al maintained at a constant temperature of 1123 K and at a constant agitation speed of 250 r/min, the treatment time was 240 min and the ZnO particle size was 450-500 mesh. The results show an increase in Zn concentration in the prepared alloys up to 5.43wt% for the highest initial concentration of Mg. The reaction products obtained were characterized by scanning electron microscopy and X-ray diffraction, and the efficiency of the reaction was measured on the basis of the different concentrations of Mg studied.

  1. Effect of magnesium on the aluminothermic reduction rate of zinc oxide obtained from spent alkaline battery anodes for the preparation of Al-Zn-Mg alloys

    Institute of Scientific and Technical Information of China (English)

    Rocio Ochoa; Alfredo Flores; Jesus Torres

    2016-01-01

    The aluminothermic reduction of zinc oxide (ZnO) from alkaline battery anodes using molten Al may be a good option for the elaboration of secondary 7000-series alloys. This process is affected by the initial content of Mg within molten Al, which decreases the sur-face tension of the molten metal and conversely increases the wettability of ZnO particles. The effect of initial Mg concentration on the alu-minothermic reduction rate of ZnO was analyzed at the following values:0.90wt%, 1.20wt%, 4.00t%, 4.25wt%, and 4.40wt%. The ZnO par-ticles were incorporated by mechanical agitation using a graphite paddle inside a bath of molten Al maintained at a constant temperature of 1123 K and at a constant agitation speed of 250 r/min, the treatment time was 240 min and the ZnO particle size was 450-500 mesh. The re-sults show an increase in Zn concentration in the prepared alloys up to 5.43wt%for the highest initial concentration of Mg. The reaction products obtained were characterized by scanning electron microscopy and X-ray diffraction, and the efficiency of the reaction was measured on the basis of the different concentrations of Mg studied.

  2. A CASE STUDY OF BRAIN VOLUME REDUCTION IN MULTIPLE SCLEROSIS

    Directory of Open Access Journals (Sweden)

    Ivan N. Dimitrov

    2013-07-01

    Full Text Available The development of sophisticated magnetic resonance imaging techniques and software for medical imaging processing and analysis has led to a significant progress in multiple sclerosis research and clinical care. The measurement of brain volumes provides a quantitative representation of damage, thus facilitating the objective follow-up process. The parameters obtained, though not being used routinely in clinical practice, are more and more often applied in clinical studies. The amount of whole brain and regional atrophy, estimated from serial scans, is considered important not only for disease progression, but also for cognitive dysfunction which is common in multiple sclerosis. In this paper we describe a volumetric study of two magnetic resonance scans of a patient with relapsing-remitting multiple sclerosis, performed 16 months one after the other, and analyzed using FSL SIENA software. Analysis demonstrated brain volume reduction of 1.7% between the two scans. We discuss the advantages of the method and its possible clinical applications.

  3. Wilder Bancroft's Study of Oxidant-Reductant Cells

    Science.gov (United States)

    Stock, John T.

    1998-07-01

    Wilder Dwight Bancroft (1867 -1953), a Harvard graduate, entered Ostwald's Leipzig laboratory in 1890. Bancroft made a systematic study of potentiometric cells in which one half contained an oxidant solution, the other half a reductant solution. He stressed the importance of the equilibration of the platinum electrodes, examined the effects of acidity and of concentration on the emf of a cell, and demonstrated that this emf was the algebraic sum of the potentials of the half-cells. After receipt of his Ph.D. in 1892, Bancroft continued his potentiometric studies in Amsterdam. Following a brief return to Harvard, Bancroft moved to Cornell, and remained there until his retirement in 1937. He founded and edited the Journal of Physical Chemistry, and was President of the American Chemical Society in 1910. He was also twice President of the Electrochemical Society.

  4. Preparation of Pt-Ru@ polypyrrole-MWNT catalysts by gamma-irradiation and chemical reduction and their adsorption capacity for CO.

    Science.gov (United States)

    Bae, Hyoung-Bong; Oh, Sang-Hyub; Woo, Jin-Chun; Choi, Seong-Ho

    2010-10-01

    With the objective to prepare electrocatalysts with high efficiency, the Pt-Ru@PPy-MWNT catalysts were prepared by different approaches. First, the polypyrrole (PPy) as anchoring materials was coated on the surface of multi walled carbon nanotubes (MWNT) by in situ polymerization. Subsequently, Pt-Ru nanoparticles were deposited onto PPy-MWNT composite by different methods like the reduction of metal ions by gamma-irradiation and chemical reduction using formaldehyde as reducing agent assisted with stirring of magnetic bar, and assisted with microwave irradiation, and assisted with ultrasonic irradiation, in order to prepare electrocatalyst for fuel cell. The catalytic efficiency of Pt-Ru@PPy-MWNT catalyst was examined for CO stripping.

  5. Does smoking reduction result in reduction of biomarkers associated with harm? A pilot study using a nicotine inhaler.

    Science.gov (United States)

    Hurt, R D; Croghan, G A; Wolter, T D; Croghan, I T; Offord, K P; Williams, G M; Djordjevic, M V; Richie, J P; Jeffrey, A M

    2000-11-01

    The aim of the study was to determine if smoking reduction using a nicotine inhaler in heavy cigarette smokers who wanted to reduce but not stop smoking results in decreased levels of known biomarkers of harm. The study design was a one-sample within-subject comparative open-label study of 23 (10 male and 13 female) subjects using a nicotine inhaler to reduce smoking, with follow-up at 24 weeks. A structured protocol was used with a smoking-reduction schedule from 40 or more cigarettes per day to 10 cigarettes per day by week 9. Behavioral counseling was provided by a research assistant and ad lib use of the nicotine inhaler for 12 weeks was permitted. Blood thiocyanate, cotinine, 4-aminobiphenyl hemoglobin adducts; urine NNAL and NNAL-glucuronide; and expired air carbon monoxide were measured. On average, the subjects were able to reduce their smoking by over 50% at week 12, but only two were able to reduce to 10 cigarettes per day. The reported reduction in smoking was not associated with a consistent reduction in the biomarkers. There was no reduction in the NNAL, 4-aminobiphenyl hemoglobin adducts nor carbon monoxide levels of expired air. There was a significant reduction of NNAL-glucuronide and the sum of NNAL and NNAL-glucuronide but only at week 24. Thiocyanate levels increased. Before widely promoting harm reduction as a treatment strategy for heavy smokers, more research needs to be performed to prove conclusively that such smokers who want to reduce but not stop can actually reduce and maintain their smoking rate at a level which is likely to reduce harm. It also needs to be determined whether a reduction in the smoking rate translates into reduction of harm. At the present, for heavy smokers, an abstinence approach seems to be more scientifically sound.

  6. Comparative studies on single-layer reduced graphene oxide films obtained by electrochemical reduction and hydrazine vapor reduction

    Science.gov (United States)

    Wang, Zhijuan; Wu, Shixin; Zhang, Juan; Chen, Peng; Yang, Guocheng; Zhou, Xiaozhu; Zhang, Qichun; Yan, Qingyu; Zhang, Hua

    2012-02-01

    The comparison between two kinds of single-layer reduced graphene oxide (rGO) sheets, obtained by reduction of graphene oxide (GO) with the electrochemical method and hydrazine vapor reduction, referred to as E-rGO and C-rGO, respectively, is systematically studied. Although there is no morphology difference between the E-rGO and C-rGO films adsorbed on solid substrates observed by AFM, the reduction process to obtain the E-rGO and C-rGO films is quite different. In the hydrazine vapor reduction, the nitrogen element is incorporated into the obtained C-rGO film, while no additional element is introduced to the E-rGO film during the electrochemical reduction. Moreover, Raman spectra show that the electrochemical method is more effective than the hydrazine vapor reduction method to reduce the GO films. In addition, E-rGO shows better electrocatalysis towards dopamine than does C-rGO. This study is helpful for researchers to understand these two different reduction methods and choose a suitable one to reduce GO based on their experimental requirements.

  7. Selective catalytic reduction of NOx with NH3 over iron-cerium-tungsten mixed oxide catalyst prepared by different methods

    Science.gov (United States)

    Xiong, Zhi-bo; Liu, Jing; Zhou, Fei; Liu, Dun-yu; Lu, Wei; Jin, Jing; Ding, Shi-fa

    2017-06-01

    A series of magnetic Fe0.85Ce0.10W0.05Oz catalysts were synthesized by three different methods(Co-precipitation(Fe0.85Ce0.10W0.05Oz-CP), Hydrothermal treatment assistant critic acid sol-gel method(Fe0.85Ce0.10W0.05Oz-HT) and Microwave irradiation assistant critic acid sol-gel method(Fe0.85Ce0.10W0.05Oz-MW)), and the catalytic activity was evaluated for selective catalytic reduction of NO with NH3. The catalyst was characterized by XRD, N2 adsorption-desorption, XPS, H2-TPR and NH3-TPD. Among the tested catalysts, Fe0.85Ce0.10W0.05Oz-MW shows the highest NOx conversion over per gram in unit time with NOx conversion of 60.8% at 350 °C under a high gas hourly space velocity of 1,200,000 ml/(g h). Different from Fe0.85Ce0.10W0.05Oz-CP catalyst, there exists a large of iron oxide crystallite(γ-Fe2O3 and α-Fe2O3) scattered in Fe0.85Ce0.10W0.05Oz catalysts prepared through hydrothermal treatment or microwave irradiation assistant critic acid sol-gel method, and higher iron atomic concentration on their surface. And Fe0.85Ce0.10W0.05Oz-MW shows higher surface absorbed oxygen concentration and better dispersion compared with Fe0.85Ce0.10W0.05Oz-HT catalyst. These features were favorable for the high catalytic performance of NO reduction with NH3 over Fe0.85Ce0.10W0.05Oz-MW catalyst.

  8. Preparation, characterization, and dye removal study of activated carbon prepared from palm kernel shell.

    Science.gov (United States)

    García, Juan Rafael; Sedran, Ulises; Zaini, Muhammad Abbas Ahmad; Zakaria, Zainul Akmar

    2017-04-08

    Palm oil mill wastes (palm kernel shell (PKS)) were used to prepare activated carbons, which were tested in the removal of colorants from water. The adsorbents were prepared by 1-h impregnation of PKS with ZnCl2 as the activating agent (PKS:ZnCl2 mass ratios of 1:1 and 2:1), followed by carbonization in autogenous atmosphere at 500 and 550 °C during 1 h. The characterization of the activated carbons included textural properties (porosity), surface chemistry (functional groups), and surface morphology. The dye removal performance of the different activated carbons was investigated by means of the uptake of methylene blue (MB) in solutions with various initial concentrations (25-400 mg/L of MB) at 30 °C, using a 0.05-g carbon/50-mL solution relationship. The sample prepared with 1:1 PKS:ZnCl2 and carbonized at 550 °C showed the highest MB adsorption capacity (maximum uptake at the equilibrium, q max = 225.3 mg MB / g adsorbent), resulting from its elevated specific surface area (BET, 1058 m(2)/g) and microporosity (micropore surface area, 721 m(2)/g). The kinetic experiments showed that removals over 90% of the equilibrium adsorptions were achieved after 4-h contact time in all the cases. The study showed that palm oil mill waste biomass could be used in the preparation of adsorbents efficient in the removal of colorants in wastewaters.

  9. 自还原体系银导电墨水的制备与低温印制导电图形的研究%Preparation of self-reductive silver inks and studying on fabrication of conductive patterns at low temperatures

    Institute of Scientific and Technical Information of China (English)

    曹洪银; 唐耀; 王守绪; 何为; 毛英捷

    2013-01-01

      总结了开发一种简便快捷的可印制在挠性基板上于低温条件实现烧结形成高导电性线路的自还原型银导电墨水的制备方法。该导电墨水通过混合二乙醇胺溶液和银氨溶液制备得到。印制在塑料基材上后,在75℃下固化形成导电线路。这是因为在碱性环境与高于50℃的温度下,二乙醇胺可分解生成甲醛并自发地与银氨溶液发生反应。随后还原出银原子并让其吸附在基材上形成银薄膜。用该方法印制得到的银线其导电率可达到金属银导电率的20%,通过继续改进可应用于各种印制电子技术中。%In this paper we will report a convenient and efficient method to generate silver tracks with high electrical conductivity on flexible substrates at low sintering temperatures by using a self-reductive silver inks. The inks are prepared by the mixture of Diethanolamine (DEA) solution and silver ammonia solution. After being printed on substrate, silver inks were sintered at 65℃generating conductive tracks. Because under the condition of alkaline and higher temperatures than 50℃, formaldehyde generated from DEA would spontaneously react with silver ammonia ions. Subsequently the sliver atoms would be reduced and adsorb on the substrate forming a silver thin films. The resulting conductivity of the printed silver tracks using this method can reach 20%of the bulk silver value, which enables various applications of printed electronics technologies.

  10. [Preparation of recombinant human insulin--study of downstream process].

    Science.gov (United States)

    Yu, Rong; Li, Xiaohong; Yang, Jiyu; Wu, Wutong

    2004-10-01

    This study was intended to establish a method of preparation of recombinant human insulin, with (His)6-Arg-Arg-human proinsulin (RRhPI) expressed by Escherichia coli. After DEAE-Sepharose Fast Flow ion-exchange chromatography, Sephadex G-25 chromatography and refolding, enzyme cleavage and Superdex 75 size exclusion chromatography,the RRhPI expressed by Escherichia coli in inclusion body form was converted to human insulin. The obtained recombinant human insulin was analyzed by SDS-PAGE, HPLC, amino acid composition analysis and bioidentity test (mouse convulsion test). The results indicate that our obtained preparation is highly purified, active recombinant human insulin.

  11. Preparation And Study Of Electrodeposited Silver-Nickel Binary System

    Science.gov (United States)

    Santhi, Kalavathy; Narmatha, R.; Narayanan, V.; Stephen, A.

    2011-06-01

    Ag-Ni binary system was prepared by the method of pulsed electrodeposition from an electrolyte that consisted of silver nitrate and nickel sulfate along with the complexing agents thiourea and sodium gluconate. The depositions were carried out by applying short current pulses of different current densities through electrolytes of same composition. The deposits were characterized using X-ray diffraction, vibrating sample magnetometer, energy dispersive X-ray analysis and SEM. The samples in their as prepared form exhibit ferromagnetic properties. This study shows that it is possible to simultaneously deposit the two immiscible constituents Ag and Ni with desired magnetic properties in pulsed electrolysis.

  12. Synchronistic preparation of fibre-like SiC and cubic-ZrO{sub 2}/SiC composite from zircon via carbothermal reduction process

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Youguo; Liu, Yangai [School of Materials Science and Technology, China University of Geosciences (Beijing), Beijing 100083 (China); Huang, Zhaohui, E-mail: huang118@cugb.edu.cn [School of Materials Science and Technology, China University of Geosciences (Beijing), Beijing 100083 (China); Fang, Minghao [School of Materials Science and Technology, China University of Geosciences (Beijing), Beijing 100083 (China); Hu, Xiaozhi [School of Mechanical and Chemical Engineering, University of Western Australia, Perth, WA 6009 (Australia); Yin, Li; Huang, Juntong [School of Materials Science and Technology, China University of Geosciences (Beijing), Beijing 100083 (China)

    2013-01-15

    Graphical abstract: Display Omitted Highlights: ► Zircon carbothermal reduction was carried out in a tailor-made device at high-temperature air atmosphere. ► Fibre-like SiC and cubic-ZrO{sub 2}/SiC composite were obtained synchronically. ► Zirconium and silicon in zircon ore was initial separated. ► [SiO{sub 4}] was mutated to fibre-like SiC, while [ZrO{sub 8}] was transformed to cubic ZrO{sub 2}. ► The SiC were surprisingly enriched in the reducing atmosphere charred coal particles layers by gas–solid reaction. -- Abstract: Fibre-like SiC and cubic-ZrO{sub 2}/SiC composite were prepared respectively from zircon with yttrium oxide addition via carbothermal reduction process at 1600 °C for 4 h in an air atmosphere furnace, where the green samples were immerged in charred coal particles inside a high-temperature enclosed corundum crucible. The reaction products were characterized by XRD, XRF, XPS and SEM. The results indicate that ZrO{sub 2} in the products was mainly existed in the form of cubic phase. The reacted samples mainly contain cubic ZrO{sub 2}, β-SiC and trace amounts of zircon, with the SiC accounting for 14.8 wt%. Furthermore, a large quantity of fibre-like SiC was surprisingly found to concentrate in the charred coal particles layers around the samples. This study obtains fibre-like SiC and cubic-ZrO{sub 2}/SiC composite synchronically from zircon via carbothermal reduction process, which also bring a value-added high-performance application for natural zircon.

  13. Preparing Global Citizens through the Study of Human Rights

    Science.gov (United States)

    Kirkwood-Tucker, Toni Fuss

    2012-01-01

    The preparation of students for global citizenship represents a central challenge to social studies educators in the twenty-first century. Two-thirds of the world's poor are steeped in abject poverty and its grim consequences. The world refugee problem has reached staggering proportions. There is an international epidemic of human trafficking, and…

  14. Psychological Preparation for Paralympic Athletes: A Preliminary Study.

    Science.gov (United States)

    Blumenstein, Boris; Orbach, Iris

    2015-07-01

    Since the first Paralympics in 1960 there has been an increase in social and scientific interest in Paralympic athletes' personality, their preparation, and their sport results. During the last 20 yr, researchers and practitioners have been focused on psychological-skills programs for athletes with disabilities. The purpose of this article was to describe a psychological-preparation program for Israeli Paralympic athletes. Two subprograms, the learning-modification-application approach and the Simulation Training Exercise Program, were adapted to athletes' disability and sport demands. Two case studies, from table tennis and sailing (Sonar 3-person keelboat), are described to demonstrate how systematic sport psychology preparation can be effectively integrated into the training process of Paralympic athletes. Some recommendations for Paralympic athletes are presented.

  15. Study on Reduction of Sulfur Content in FCC Gasoline

    Institute of Scientific and Technical Information of China (English)

    Hou Dianguo

    2003-01-01

    Reduction of sulfur content in FCC gasoline was studied in a fixed fluid bed (FFB) unit by using metal-modified LV-23 FCC catalyst. The results showed that the sulfur content in FCC gasoline could be reduced with LV-23 catalyst modified with zinc, palladium, zinc-palladium, zinc-cobalt, and zinc-nickel. Among these metals or metal combinations, palladium-containing catalyst was the most effective. Desulfurization of the heavy fraction of FCC gasoline was more effective than full-range gasoline under the same conditions with palladium-containing catalysts. A high reaction temperature was favorable to desulfurization, but it would reduce the yield of liquid product. After desulfurization reaction, the olefin content of product gasoline decreased while the aromatic and iso-alkane contents increased. Removal of thiophene and benzothiophene is higher.

  16. Pilot-scale study of biomass reduction in wastewater treatment.

    Science.gov (United States)

    Wang, Qunhui; Ai, Hengyu; Li, Xuesong; Liu, Haitao; Xie, Weimin

    2007-05-01

    Pilot-scale experiments were continuously carried out for more than 9 months to study the excess biomass reduction effect using a biophase-separation bioreactor, which was designed based on food-chain theory. By separating the biophase in the wastewater treatment system, bacteria, protozoa, and metazoa could be separated from each other and dominated in different microbial communities. After degrading organic matter, bacteria were consumed by protozoa or metazoa in the following process in such a reactor. Thus, both chemical oxygen demand (COD) and biomass were reduced. During the process of treating restaurant wastewater, the excess biomass yield in this biophase-separation technique varied from 0.13 to 0.22 kg/kg COD removed, 50% lower than that from the reference system. Apart from low biomass production, this biophase-separation technique can simultaneously achieve a high COD removal efficiency and improve settleability of biosolids at a hydraulic retention time of 6 to 13 hours.

  17. Preparation of asymmetrically distributed bimetal ceria (CeO₂) and copper (Cu) nanoparticles in nitrogen-doped activated carbon micro/nanofibers for the removal of nitric oxide (NO) by reduction.

    Science.gov (United States)

    Bhaduri, Bhaskar; Verma, Nishith

    2014-12-15

    A novel multi-scale web of carbon micro/nanofibers (ACF/CNF) was prepared by the catalytic chemical vapor deposition (CCVD), in which CeO2 and Cu nanoparticles (NPs) were in-situ incorporated during a synthesis step. The CVD temperature was adjusted such that the prepared material had asymmetric distribution of the bimetals, with the Cu NPs located at the tips of the CNFs and the CeO2 particles adhered to the surface of the ACF substrate. The prepared bimetals-dispersed web of ACF/CNF was treated with pyridine and the surface functionalized material was applied for the removal of NO by reduction. The complete reduction of NO was achieved at 500°C and for 400ppm NO concentration. Whereas the Cu NPs acted as the catalyst for the reduction, CeO2 facilitated the incorporation of nitrogen from the pyridine source into the ACF/CNF surface. The produced nitrogen containing surface functional groups enhanced the reactivity of the material toward the NO. The bimetals CeO2 and Cu nanoparticles (NPs)-dispersed ACF/CNF produced in this study is a potential candidate for effectively removing NO by reduction, without requiring urea or ammonia used in conventional abatement methods. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Preparation and characterizations of BiVO₄/reduced graphene oxide nanocomposites with higher visible light reduction activities.

    Science.gov (United States)

    Wang, Aolan; Shen, Song; Zhao, Yibo; Wu, Wei

    2015-05-01

    Bismuth vanadate/reduced graphene oxide (BiVO4/RGO) composites were synthesized by one-step hydrothermal method with graphite oxide, Bi(NO3)3 and NH4VO3 as precursors. The as-synthesized nanocomposites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, UV-Vis spectroscopy (UV), fluorescence spectroscopy (FL) and electrochemical impedance spectroscopy (EIS). The reduced graphene oxide sheets were decorated by butterfly-like BiVO4 lamellas. Such combination not only alleviated the agglomeration of BiVO4 particles but also restrained the restacking of reduced graphene oxide. A preliminary study on the photo-reductions of Cr (VI) and CO2 under the illumination of simulated sunlight with as-synthesized BiVO4/RGO nanocomposites as catalyst was carried out. The nanocomposites showed better photo-catalytic activity than the conventional BiVO4 particles. The photo-reduction efficiency of BiVO4/RGO nanocomposites increased about 50.1% and the ethanol yield improved about 15.4 μmol/g-cat comparing with pure BiVO4. The enhancements of the photo-catalytic activities were attributed to the effective charge transfer of photo-generated electron from BiVO4 to RGO and improved absorption performance.

  19. [Study on preparation process of artesunate polylactic acid microspheres].

    Science.gov (United States)

    Pan, Xu-Wang; Wang, Wei; Fang, Hong-Ying; Wang, Fu-Gen; Cai, Zhao-Bin

    2013-12-01

    This study aims to investigate the preparation process and in vitro release behavior of artesunate polylactic acid microspheres, in order to prepare an artesunate polylactic acid (PLA) administration method suitable for hepatic arterial embolization. With PLA as the material and polyvinyl alcohol (PVA) as the emulsifier, O/W emulsion/solvent evaporation method was adopted to prepare artesunate polylactic acid microspheres, and optimize the preparation process. With drug loading capacity, encapsulation efficiency and particle size as indexes, a single factor analysis was made on PLA concentration, PVA concentration, drug loading ratio and stirring velocity. Through an orthogonal experiment, the optimal processing conditions were determined as follows: PLA concentration was 9. 0% , PVA concentration was 0. 9% , drug loading ratio was 1:2 and stirring velocity was 1 000 r x min(-1). According to the verification of the optimal process, microsphere size, drug loading and entrapment rate of artesunate polylactic acid microspheres were (101.7 +/- 0.37) microm, (30.8 +/- 0.84)%, (53.6 +/- 0.62)%, respectively. The results showed that the optimal process was so reasonable and stable that it could lay foundation for further studies.

  20. Preparation and study of properties of dispersed graphene oxide

    Directory of Open Access Journals (Sweden)

    Evgeniya Seliverstova

    2015-09-01

    Full Text Available Ability of graphene oxide to form stable dispersion in organic solvents was studied in this work. As it was shown, sonication of graphene leads to the decreas of the particle size. Stability of prepared graphene dispersions was studied upon measurements of distribution of number of the particles via size and change of optical density of the solutions with time. It was found that graphene oxide forms a more stable dispersion in tetrahydrofuran and dimethylformamide than in chloroform and acetone.

  1. Solid Waste Reduction--A Hands-on Study.

    Science.gov (United States)

    Wiessinger, Diane

    1991-01-01

    This lesson plan uses grocery shopping to demonstrate the importance of source reduction in the handling of solid waste problems. Students consider different priorities in shopping (convenience, packaging, and waste reduction) and draw conclusions about the relationship between packaging techniques and solid waste problems. (MCO)

  2. A pilot study on mindfulness based stress reduction for smokers

    Directory of Open Access Journals (Sweden)

    Baker Timothy B

    2007-01-01

    Full Text Available Abstract Background Mindfulness means paying attention in the present moment, non-judgmentally, without commentary or decision-making. We report results of a pilot study designed to test the feasibility of using Mindfulness Based Stress Reduction (MBSR (with minor modifications as a smoking intervention. Methods MBSR instructors provided instructions in mindfulness in eight weekly group sessions. Subjects attempted smoking cessation during week seven without pharmacotherapy. Smoking abstinence was tested six weeks after the smoking quit day with carbon monoxide breath test and 7-day smoking calendars. Questionnaires were administered to evaluate changes in stress and affective distress. Results 18 subjects enrolled in the intervention with an average smoking history of 19.9 cigarettes per day for 26.4 years. At the 6-week post-quit visit, 10 of 18 subjects (56% achieved biologically confirmed 7-day point-prevalent smoking abstinence. Compliance with meditation was positively associated with smoking abstinence and decreases in stress and affective distress. Discussions and conclusion The results of this study suggest that mindfulness training may show promise for smoking cessation and warrants additional study in a larger comparative trial.

  3. Preparation and study of dialkyl nitroxide radicals; Preparation et etude de radicaux nitroxydes diacyles

    Energy Technology Data Exchange (ETDEWEB)

    Chenavas, P. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1969-07-01

    These radicals are obtained by oxidation of N-hydroxy-imides with lead tetracetate or p-nitro-perbenzoic acid. These imides are prepared by heating dicarboxylic acids anhydrides with benzyloxy-amine followed by catalytic hydrogenation of N-benzyloxy-imides so obtained. Two series of radicals have mainly been studied, the first concerning five-membered cyclic imides, the second six-membered cyclic imides, these molecules having methyls substituents or no on the carbon ring. N. M. R. spectra of some O-benzyl-imides have been analysed. These different results have made it possible to study the conformation and stereochemistry of these imides. (author) [French] Ces radicaux sont obtenus par oxydation d'imides N-hydroxyles par le tetracetate de plomb ou l'acide p-nitroperbenzoique; ces imides sont prepares par chauffage d'anhydrides de diacides en presence de benzyloxyamine suivie d'une hydrogenation catalytique des N-benzyloxyimides ainsi obtenus. Deux series de radicaux ont principalement ete etudies: la premiere relative a des imides cycliques a cinq chainons, la seconde a des imides cycliques a six chainons, ces molecules ayant des substituants methyles ou non sur la chaine carbonee. Les derives O-benzyles de quelques-uns de ces imides ont ete analyses en R. M. N. Ces differents resultats ont permis une etude de la conformation et de la stereochimie de ces imides. (auteur)

  4. ''In-house'' pharmacological management for computed tomography coronary angiography: heart rate reduction, timing and safety of different drugs used during patient preparation

    Energy Technology Data Exchange (ETDEWEB)

    Maffei, Erica; Tedeschi, Carlo; Seitun, Sara; Ruffini, Livia; Aldrovandi, Annachiara [Azienda Ospedaliero - Universitaria di Parma, Department of Radiology and Cardiology, Parma (Italy); Palumbo, Alessandro A.; Martini, Chiara [Azienda Ospedaliero - Universitaria di Parma, Department of Radiology and Cardiology, Parma (Italy); Erasmus Medical Center, Department of Radiology and Cardiology, Rotterdam (Netherlands); Tarantini, Giuseppe [Azienda Ospedaliero - Universitaria di Parma, Department of Radiology and Cardiology, Parma (Italy); University of Padua, Department of Cardiology, Padua (Italy); Weustink, Annick C.; Meijboom, Willem B.; Mollet, Nico R.; Krestin, Gabriel P.; Feyter, Pim J. de [Erasmus Medical Center, Department of Radiology and Cardiology, Rotterdam (Netherlands); Cademartiri, Filippo [Azienda Ospedaliero - Universitaria di Parma, Department of Radiology and Cardiology, Parma (Italy); Erasmus Medical Center, Department of Radiology and Cardiology, Rotterdam (Netherlands); Azienda Ospedaliero-Universitaria - Parma, Department of Radiology c/o Piastra Tecnica - Piano 0, Parma (Italy)

    2009-12-15

    We retrospectively evaluated the effect, timing and safety of different pharmacological strategies during 64-slice CT coronary angiography (CT-CA). From the institutional database of CT-CA we enrolled 560 consecutive patients with suspected coronary artery disease. The type of drug preparation (group 1 = no treatment; group 2 = oral metoprolol; group 3 = other; group 4 = intravenous (IV) atenolol; group 5 = IV atenolol + nitrates; NR = non-responders), timing, and adverse effects were recorded. Heart rate (HR) during different preparation phases was recorded. Four adverse effects were recorded, none of which was attributable to pharmacological treatment. In all groups, except group 1, the HR on arrival was significantly reduced by the pharmacological treatment (p < 0.01). Group 4 showed the best (-16 {+-} 8 bpm) HR reduction. There was no significant effect on HR due to nitrates (p = 0.49), while a slight increase due to contrast material was noted (p < 0.05). Average time required for preparation was 44 {+-} 25 min. Groups 4 and 5 showed the most effective timing (8 {+-} 9 min and 8 {+-} 8 min, respectively; p < 0.01). Pharmacological preparation in patients undergoing CT-CA is safe and effective. Best results in terms of HR reduction and fast preparation are obtained with IV administration of beta-blockers. (orig.)

  5. Highly dispersed TaOx nanoparticles prepared by electrodeposition as oxygen reduction electrocatalysts for polymer electrolyte fuel cells

    KAUST Repository

    Seo, Jeongsuk

    2013-06-06

    Based on the chemical stability of group IV and V elements in acidic solutions, TaOx nanoparticles prepared by electrodeposition in an ethanol-based Ta plating bath at room temperature were investigated as novel nonplatinum electrocatalysts for the oxygen reduction reaction (ORR) in polymer electrolyte fuel cells (PEFCs). Electrodeposition conditions of Ta complexes and subsequent various heat treatments for the deposited TaOx were examined for the best performance of the ORR. TaOx particles on carbon black (CB), electrodeposited at a constant potential of -0.5 V Ag/AgCl for 10 s and then heat-treated by pure H2 flow at 523 K for 1 h, showed excellent catalytic activity with an onset potential of 0.93 VRHE (for 2 μA cm-2) for the ORR. Surface characterizations of the catalysts were performed by scanning transmission electron microscopy (STEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDS). The loading amounts of the electrodeposited material on the CB were determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES). All the physical results suggested that high dispersion of TaOx particles on the CB surface with 2-3 nm size was critical and key for high activity. The chemical identity and modified surface structure for the deposited TaOx catalysts before and after H 2 heat treatment were analyzed by X-ray photoelectron spectroscopy (XPS). The formation of more exposed active sites on the electrode surface and enhanced electroconductivity of the tantalum oxide promoted from the H 2 treatment greatly improved the ORR performance of the electrodeposited TaOx nanoparticles on CB. Finally, the highly retained ORR activity after an accelerated durability test in an acidic solution confirmed and proved the chemical stability of the oxide nanoparticles. The high utilization of the electrodeposited TaOx nanoparticles uniformly dispersed on CB for the ORR was comparable to that of commercial Pt/CB catalysts

  6. Smoking reduction and biomarkers in two longitudinal studies

    DEFF Research Database (Denmark)

    Godtfredsen, Nina; Prescott, Eva; Vestbo, Jørgen

    2006-01-01

    /83 and 1991/94, and the Copenhagen Male Study (CMS) in 1976 and 1985/86, respectively. PARTICIPANTS: There were 3026 adults who were smokers at both time-points in the CCHS and 1319 men smoking at both time-points in the CMS. MEASUREMENTS: Smoking status and tobacco consumption were assessed by self......-completion questionnaire. Measurements of biomarkers of smoke intake were taken at the second time-point in the two studies: expired-air carbon monoxide (CO) in the CCHS and serum cotinine in the CMS. Biomarker levels in medium (15-29 g tobacco/day) and heavy (> 30 g/day) smokers at the first time-point who later reported...... a reduction in cigarettes per day of 50% or more without quitting were compared with continuing medium, heavy and light smokers (1-14 g/day) using linear regression. Sex (CCHS only), age, self-reported inhalation of smoke, duration of smoking, type of tobacco and amount smoked were included as covariates...

  7. Open reduction and internal fixation: Screw injury - Retrospective study

    Directory of Open Access Journals (Sweden)

    Preetha Balaji

    2017-01-01

    Full Text Available Background/Aims: Open reduction and internal fixation (ORIF is a standard surgical procedure in jaw trauma and in orthognathic surgery. Insertion of screws is a significant risk for accidental tooth root injury with varying outcomes. Contrary evidences are found in literature due to a variety of study designs. This study was undertaken to address the lacunae and possibly estimate the difference in occurrence of tooth damage during or after ORIF between trauma and planned osteotomies. Materials and Methods: In this retrospective study, the data of ORIF in either trauma or orthognathic surgery fulfilling inclusion and exclusion criteria were collected and analyzed. Results: There were 1632 patients fulfilling the inclusion and exclusion criteria and formed the study group, of which 663 were in orthognathic surgery, of whom 210 had bimaxillary orthognathic surgery. In the trauma group, 358 patients had fractures involving both jaws whereas 272 had maxilla alone and 339 had mandibular fractures alone. On comparing the outcome, of the 9073 screws studied, 93.40% were not involved in any contact with the teeth, 6.3% were in category of potential hits (near apices or the root surfaces, and only 0.28% had evidence of root damage with the screws. It is observed that molar and premolar had a significant difference in terms of the type of surgery (P ≤ 0.05 whereas canine (P = 0.75 and incisor (P = 0.67 showed no statistical difference. Conclusion: ORIF when used as mentioned is a safe way for the management of fractures. The incidence of root injury is not uncommon but can be avoided with careful planning and execution.

  8. The TRINITY Study: distribution of systolic blood pressure reductions

    Directory of Open Access Journals (Sweden)

    Sugimoto DH

    2013-07-01

    Full Text Available Danny H Sugimoto,1 Steven G Chrysant,2 Michael Melino,3 James Lee,3 Victor Fernandez,3 Reinilde Heyrman41Cedar-Crosse Research Center and Rush Medical College, Chicago, IL, USA; 2Oklahoma Cardiovascular and Hypertension Center and Department of Cardiology, University of Oklahoma College of Medicine, Oklahoma City, OK, USA; 3Department of Clinical Development, Daiichi Sankyo, Inc, Parsippany, NJ, USA; 4Formerly of the Department of Clinical Development, Daiichi Sankyo, Inc, Parsippany, NJ, USABackground: Elevated systolic blood pressure is more difficult to control than elevated diastolic blood pressure. The objective of this prespecified analysis of the Triple Therapy with Olmesartan Medoxomil, Amlodipine, and Hydrochlorothiazide in Hypertensive Patients Study (TRINITY was to compare the efficacy of olmesartan medoxomil (OM 40 mg, amlodipine besylate (AML 10 mg, and hydrochlorothiazide (HCTZ 25 mg triple-combination treatment with the component dual-combination treatments in reducing elevated seated systolic blood pressure (SeSBP.Methods: The 12-week TRINITY study randomized participants to either one of the three component dual-combination treatments (OM 40 mg/AML 10 mg, OM 40 mg/HCTZ 25 mg, or AML 10 mg/HCTZ 25 mg or the triple-combination treatment. The primary outcome of this analysis was the categorical distribution of SeSBP reductions at week 12 from baseline with OM 40 mg/AML 10 mg/HCTZ 25 mg versus the dual-combination treatments.Results: SeSBP reductions >50 mmHg were seen in 24.4% of participants receiving triple-combination treatment versus 8.1%–15.8% receiving dual-combination treatment. More participants receiving triple-combination treatment achieved the SeSBP target of <140 mmHg (73.6% versus 51.3%–58.8%; P < 0.001 and the seated blood pressure target of <140/90 mmHg (69.9% versus 41.1%–53.4%; P < 0.001. Prevalence and severity of adverse events were similar in all treatment groups.Conclusion: Treatment with OM 40 mg/AML 10

  9. Study of bagasse/tapioca starch film preparation and characterization

    Science.gov (United States)

    Chen, Yanyang; Wei, Xiaoyi; Chang, Gang; Fu, Tiaokun; Cui, Lihong; Li, Jihua

    2017-06-01

    Bagasse/tapioca starch films (BT) were prepared with various contents of bagasse (10, 20, 30, 40 and 50 wt% based on tapioca starch), and the effect of bagasse concentration was studied by the performance of the BT films. Then, the BT films characteristics were analyzed using the instruments about ultraviolet spectrophotometer (US), SEM, TGA and XRD. The dispersion of the bagasse became better with bagasse concentration increasing, the intermolecular hydrogen bonding became stronger while the transparency values of the films decreased.

  10. Study on Rural Poverty Reduction Effect of Traffic Infrastructure

    Institute of Scientific and Technical Information of China (English)

    Junping; GUO; Bin; ZHANG; Xiyan; ZHANG

    2014-01-01

    To systematically comb and explore the rural poverty reduction effect of traffic infrastructure,the author analyzed the mechanism,main channels and actual effect of rural traffic infrastructure on poverty reduction.It revealed that rural traffic infrastructure exerts positive or negative effect on poverty reduction directly or indirectly.The positive channel includes increasing non-agricultural employment opportunities,reducing costs for agricultural production,transportation and labor transfer,increasing availability of social service,and promoting adjustment of agricultural industrial structure and development of rural tourism resources.On the whole,traffic infrastructure has significant positive influence on rural poverty reduction.Finally,it summarized policy recommendations for building pro-poor traffic infrastructure,and came up with vacancy of related research field and future exploration direction.

  11. The Preparation of Matrine Liposome and Its Antiglioma Activity Study

    Directory of Open Access Journals (Sweden)

    Shao-Rong Han

    2014-01-01

    Full Text Available The aim of the study was to study the preparation of matrine liposome and its activity for resisting cells, to study the preparation of matrine liposome by orthogonal design, and to observe the inhibiting effect of matrine on glioma through MTT method, Flow Cytometer, and electron microscope. The results showed that we take the encapsulation efficiency as the index; the optimal preparation of matrine liposome is 100 mg of lecithin, 40 mg of cholesterol, phosphate buffered saline (PBS with pH value 6.4, and 40 mg of matrine. The result of MTT testing is shown that the tested group with medium and high dosage (0.75, 1.0, 1.25 mg/L of matrine has significant inhibiting rate to the growth of BT 325 cells. The A value in tested group with medium and high dosage is up to 0.19±0.03. The methods of Flow Cytometer and electron microscope prove that matrine can inhibit the growth of BT 325 cells. Matrine is active in inhibiting brain glioma.

  12. Global Obesity Study on Drivers for Weight Reduction Strategies

    Directory of Open Access Journals (Sweden)

    Carola Grebitus

    2015-01-01

    Full Text Available Objective: To assess factors determining the reaction of individuals to the threats of overweight and obesity and to examine the interdependencies between weight-reducing strategies. Methods: Cross-country survey covering 19 countries and 13,155 interviews. Data were analysed using a bivariate probit model that allows simultaneously analysing two weight-reducing strategies. Results: Results show that weight-reducing strategies chosen are not independent from each other. Findings also reveal that different strategies are chosen by different population segments. Women are more likely to change their dietary patterns and less likely to become physically active after surpassing a weight threshold. In addition, the probability of a dietary change in case of overweight differs considerably between countries. The study also reveals that attitudes are an important factor for the strategy choice. Conclusions: It is vital for public health policies to understand determinants of citizens' engagement in weight reduction strategies once a certain threshold is reached. Thus, results can support the design of public health campaigns and programmes that aim to change community or national health behaviour trends taking into account, e.g., national differences.

  13. Studies on biological reduction of chromate by Streptomyces griseus

    Energy Technology Data Exchange (ETDEWEB)

    Poopal, Ashwini C. [Division of Biochemical Sciences, National Chemical Laboratory, Dr Homi Bhabha Road, Pune 411008 (India); Laxman, R. Seeta, E-mail: rseetalaxman@yahoo.co.in [Division of Biochemical Sciences, National Chemical Laboratory, Dr Homi Bhabha Road, Pune 411008 (India)

    2009-09-30

    Chromium is a toxic heavy metal used in various industries and leads to environmental pollution due to improper handling. The most toxic form of chromium Cr(VI) can be converted to less toxic Cr(III) by reduction. Among the actinomycetes tested for chromate reduction, thirteen strains reduced Cr(VI) to Cr(III), of which one strain of Streptomyces griseus (NCIM 2020) was most efficient showing complete reduction within 24 h. The organism was able to use a number of carbon sources as electron donors. Sulphate, nitrate, chloride and carbonate had no effect on chromate reduction during growth while cations such as Cd, Ni, Co and Cu were inhibitory to varying degrees. Chromate reduction was associated with the bacterial cells and sonication was the best method of cell breakage to release the enzyme. The enzyme was constitutive and did not require presence of chromate during growth for expression of activity. Chromate reduction with cell free extract (CFE) was observed without added NADH. However, addition of NAD(P)H resulted in 2-3-fold increase in activity. Chromate reductase showed optimum activity at 28 deg. C and pH 7.

  14. A simple way to prepare Au@polypyrrole/Fe3O4 hollow capsules with high stability and their application in catalytic reduction of methylene blue dye

    Science.gov (United States)

    Yao, Tongjie; Cui, Tieyu; Wang, Hao; Xu, Linxu; Cui, Fang; Wu, Jie

    2014-06-01

    Metal nanoparticles are promising catalysts for dye degradation in treating wastewater despite the challenges of recycling and stability. In this study, we have introduced a simple way to prepare Au@polypyrrole (PPy)/Fe3O4 catalysts with Au nanoparticles embedded in a PPy/Fe3O4 capsule shell. The PPy/Fe3O4 capsule shell used as a support was constructed in one-step, which not only dramatically simplified the preparation process, but also easily controlled the magnetic properties of the catalysts through adjusting the dosage of FeCl2.4H2O. The component Au nanoparticles could catalyze the reduction of methylene blue dye with NaBH4 as a reducing agent and the reaction rate constant was calculated through the pseudo-first-order reaction equation. The Fe3O4 nanoparticles permitted quick recycling of the catalysts with a magnet due to their room-temperature superparamagnetic properties; therefore, the catalysts exhibited good reusability. In addition to catalytic activity and reusability, stability is also an important property for catalysts. Because both Au and Fe3O4 nanoparticles were wrapped in the PPy shell, compared with precursor polystyrene/Au composites and bare Fe3O4 nanoparticles, the stability of Au@PPy/Fe3O4 hollow capsules was greatly enhanced. Since the current method is simple and flexible to create recyclable catalysts with high stability, it would promote the practicability of metal nanoparticle catalysts in industrial polluted water treatment.Metal nanoparticles are promising catalysts for dye degradation in treating wastewater despite the challenges of recycling and stability. In this study, we have introduced a simple way to prepare Au@polypyrrole (PPy)/Fe3O4 catalysts with Au nanoparticles embedded in a PPy/Fe3O4 capsule shell. The PPy/Fe3O4 capsule shell used as a support was constructed in one-step, which not only dramatically simplified the preparation process, but also easily controlled the magnetic properties of the catalysts through adjusting

  15. High-rate performance of Ti3+ self-doped TiO2 prepared by imidazole reduction for Li-ion batteries

    Science.gov (United States)

    Seok, Dong-il; Wu, Mihye; Shim, Kwang Bo; Kang, Yongku; Jung, Ha-Kyun

    2016-10-01

    Ti3+ self-doped TiO2 nanoparticles were prepared via a simple imidazole reduction process and developed as an anode material for Li-ion batteries. Introducing the Ti3+-state on TiO2 nanoparticles resulted in superior rate performances that the capacity retention of 88% at 50 C. The enhanced electrochemical performances were attributed to the resulting lower internal resistance and improved electronic conductivity, based on galvanostatic intermittent titration technique and electrochemical impedance spectroscopy analyses.

  16. Microfinance institutions and a coastal community's disaster risk reduction, response, and recovery process: a case study of Hatiya, Bangladesh.

    Science.gov (United States)

    Parvin, Gulsan Ara; Shaw, Rajib

    2013-01-01

    Several researchers have examined the role of microfinance institutions (MFIs) in poverty alleviation, but the part that they play in disaster risk reduction remains unaddressed. Through an empirical study of Hatiya Island, one of the most vulnerable coastal communities of Bangladesh, this research evaluates perceptions of MFI support for the disaster risk reduction, response, and recovery process. The findings reveal no change in relation to risk reduction and income and occupation aspects for more than one-half of the clients of MFIs. In addition, only 26 per cent of them have witnessed less damage as a result of being members of MFIs. One can argue, though, that the longer the membership time period the better the disaster preparedness, response, and recovery process. The outcomes of this study could help to guide the current efforts of MFIs to enhance the ability of coastal communities to prepare for and to recover from disasters efficiently and effectively.

  17. A simple way to prepare Au@polypyrrole/Fe3O4 hollow capsules with high stability and their application in catalytic reduction of methylene blue dye.

    Science.gov (United States)

    Yao, Tongjie; Cui, Tieyu; Wang, Hao; Xu, Linxu; Cui, Fang; Wu, Jie

    2014-07-07

    Metal nanoparticles are promising catalysts for dye degradation in treating wastewater despite the challenges of recycling and stability. In this study, we have introduced a simple way to prepare Au@polypyrrole (PPy)/Fe3O4 catalysts with Au nanoparticles embedded in a PPy/Fe3O4 capsule shell. The PPy/Fe3O4 capsule shell used as a support was constructed in one-step, which not only dramatically simplified the preparation process, but also easily controlled the magnetic properties of the catalysts through adjusting the dosage of FeCl2·4H2O. The component Au nanoparticles could catalyze the reduction of methylene blue dye with NaBH4 as a reducing agent and the reaction rate constant was calculated through the pseudo-first-order reaction equation. The Fe3O4 nanoparticles permitted quick recycling of the catalysts with a magnet due to their room-temperature superparamagnetic properties; therefore, the catalysts exhibited good reusability. In addition to catalytic activity and reusability, stability is also an important property for catalysts. Because both Au and Fe3O4 nanoparticles were wrapped in the PPy shell, compared with precursor polystyrene/Au composites and bare Fe3O4 nanoparticles, the stability of Au@PPy/Fe3O4 hollow capsules was greatly enhanced. Since the current method is simple and flexible to create recyclable catalysts with high stability, it would promote the practicability of metal nanoparticle catalysts in industrial polluted water treatment.

  18. An Oxygen Reduction Study of Graphene-Based Nanomaterials of Different Origin

    Directory of Open Access Journals (Sweden)

    Jaana Lilloja

    2016-07-01

    Full Text Available The aim of this study is to compare the electrochemical behaviour of graphene-based materials of different origin, e.g., commercially available graphene nanosheets from two producers and reduced graphene oxide (rGO towards the oxygen reduction reaction (ORR using linear sweep voltammetry, rotating disc electrode and rotating ring-disc electrode methods. We also investigate the effect of catalyst ink preparation using two different solvents (2-propanol containing OH− ionomer or N,N-dimethylformamide on the ORR. The graphene-based materials are characterised by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. Clearly, the catalytic effect depends on the origin of graphene material and, interestingly, the electrocatalytic activity of the catalyst material for ORR is lower when using the OH− ionomer in electrode modification. The graphene electrodes fabricated with commercial graphene show better ORR performance than rGO in alkaline solution.

  19. Reproducible Preparation of Silver Sols with Small Particle Size Using Borohydride Reduction: For Use as Nuclei for Preparation of Larger Particles.

    Science.gov (United States)

    Shirtcliffe; Nickel; Schneider

    1999-03-01

    Silver colloids are useful as substrates for surface enhanced Raman spectroscopy (SERS). The results are, however, seldom quantitative as the distribution of particle sizes in silver suspensions can vary from sample to sample and thus the SERS spectra can vary in intensity. Monodisperse silver sols are relatively difficult to prepare compared with gold or latex colloids as the nucleation process is difficult to control. Previous workers have used a system where small particles are formed in one process and grown in a second reaction. In this paper a simple procedure is outlined by which the small, "seed" particles (starter sols) can be prepared; this method is simpler and more reproducible than that used in the past. The process by which the sols can be grown is not discussed in detail here as it is the subject of a forthcoming publication. Copyright 1999 Academic Press.

  20. Preparation of Ferrotitanium from Ilmenite by Electrolysis-Assisted Calciothermic Reduction in CaCl2-NaCl Molten Salt

    Science.gov (United States)

    Zhou, Zhongren; Hua, Yixin; Xu, Cunying; Li, Jian; Li, Yan; Gong, Kai; Ru, Juanjian; Xiong, Li

    2016-02-01

    Electrolysis-assisted calciothermic reduction method is proposed and successfully used to prepare ferrotitanium alloy from ilmenite by using equal-molar CaCl2-NaCl molten salt as electrolyte, molybdenum rod as cathode, and graphite as anode at 973 K with cell voltages of 3.2-4.4 V under inert atmosphere. Thermodynamics analysis of the process is presented, and the products obtained are examined with x-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. It is demonstrated that the calciothermic reduction of ilmenite is a stepwise process since intermediate CaTiO3 is observed in the products partially reduced. In the calciothermic reduction process, the reduction of FeTiO3 first gives rise to the formation of Fe and CaTiO3, which as intermediates will further react with calcium metal to form ferrotitanium alloys. This is in good agreement with the prediction of thermodynamics. Experimental results also show that increasing cell voltage can accelerate the formation of calcium metal through electrolysis of CaO and CaCl2 and, hence, promote the calciothermic reduction of ilmenite. As the electrolytic zone and reduction zone are combined in the same bath, the theoretical energy requirement for the production of FeTi in the calciothermic process is lower than that in the aluminothermic process.

  1. Low-temperature selective catalytic reduction of NO on CeO2-CuO/Al2O3 catalysts prepared by different methods.

    Science.gov (United States)

    Guo, Rui-Tang; Zhen, Wen-Long; Pan, Wei-Guo; Hong, Jie-Nan; Jin, Qiang; Ding, Cheng-Gang; Guo, Shi-Yi

    2014-08-01

    CeO2-CuO/Al2O3 catalysts were prepared by three different methods and their activities for selective catalytic reduction (SCR) of NO with NH3 were investigated. As can be seen from the experimental results, the catalyst prepared by the single-step sol-gel (SG) method showed the best SCR activity and resistance to SO2 and H2O. In order to investigate the relationship between the preparation method and the performance of SCR catalysts, the catalysts were characterized by using Brunauer-Emmett-Teller, X-ray diffraction, temperature programmed reduction with hydrogen, temperature programmed desorption with ammonia, X-ray photoelectron spectroscopy, Fourier transform infrared and thermo-gravimetric analysis techniques. It was found that the excellent performance of CeO2-CuO/Al2O3 catalyst prepared by the single-step SG method should be resulted from its large surface area, low crystallinity, high oxygen storage capacity, high NH3 adsorption capacity, high concentration of surface chemisorbed oxygen, weak sulphation process and weak water absorption.

  2. Low-temperature selective catalytic reduction of NO with NH3 over nanoflaky MnOx on carbon nanotubes in situ prepared via a chemical bath deposition route

    Science.gov (United States)

    Fang, Cheng; Zhang, Dengsong; Cai, Sixiang; Zhang, Lei; Huang, Lei; Li, Hongrui; Maitarad, Phornphimon; Shi, Liyi; Gao, Ruihua; Zhang, Jianping

    2013-09-01

    Nanoflaky MnOx on carbon nanotubes (nf-MnOx@CNTs) was in situ synthesized by a facile chemical bath deposition route for low-temperature selective catalytic reduction (SCR) of NO with NH3. This catalyst was mainly characterized by the techniques of X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), N2 adsorption-desorption analysis, X-ray photoelectron spectroscopy (XPS), H2 temperature-programmed reduction (H2-TPR) and NH3 temperature-programmed desorption (NH3-TPD). The SEM, TEM, XRD results and N2 adsorption-desorption analysis indicated that the CNTs were surrounded by nanoflaky MnOx and the obtained catalyst exhibited a large surface area as well. Compared with the MnOx/CNT and MnOx/TiO2 catalysts prepared by an impregnation method, the nf-MnOx@CNTs presented better NH3-SCR activity at low temperature and a more extensive operating temperature window. The XPS results showed that a higher atomic concentration of Mn4+ and more chemisorbed oxygen species existed on the surface of CNTs for nf-MnOx@CNTs. The H2-TPR and NH3-TPD results demonstrated that the nf-MnOx@CNTs possessed stronger reducing ability, more acid sites and stronger acid strength than the other two catalysts. Based on the above mentioned favourable properties, the nf-MnOx@CNT catalyst has an excellent performance in the low-temperature SCR of NO to N2 with NH3. In addition, the nf-MnOx@CNT catalyst also presented favourable stability and H2O resistance.Nanoflaky MnOx on carbon nanotubes (nf-MnOx@CNTs) was in situ synthesized by a facile chemical bath deposition route for low-temperature selective catalytic reduction (SCR) of NO with NH3. This catalyst was mainly characterized by the techniques of X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), N2 adsorption-desorption analysis, X-ray photoelectron spectroscopy (XPS), H2 temperature-programmed reduction (H2-TPR) and NH3 temperature

  3. Study on the preparation and properties of ultrafine copper powder

    Institute of Scientific and Technical Information of China (English)

    LIU; Wei-ping; HUANG; Lin; YIN; Yan-hong

    2005-01-01

    In the study, the common copper powder is used as sample, the ultrafine copper powder is researched by a new process of high energy ball milling. The influence of the milling time, the milling intensity, the milling medium, the ratio of hall to material, the dry milling and the wet milling on copper powder size are studied and the rule of every factors influencing properties of copper particle size and specific surface area under the best experimental conditions are acquired. By the regressive analysis of experimental results under the best conditions, the characteristic equation of copper particle prepared by high energy milling is confirmed.

  4. Study on Preparation and Characteristics of Pyridoxalated Polyhemoglobin

    Institute of Scientific and Technical Information of China (English)

    LiangShuguang; TongMingrong; 等

    1994-01-01

    Stroma-free hemoglobin(SFHb) was prepared from fresh or out-dated whole blood by lysing red cells.At different temperatures,pyridoxal 5-phosphate (PLP) was added in a 4:1 molar-ratio to the Hb tetramer followed by reduction with NaBH4 under N2 for 16 hrs subsequent crosslinking by glutaraldehyde in presence of lysine for 14-16 hrs.Yielded soluble pyridoxalated polyhemoglobin (Poly Hb-P).5%-20% gradient SDS-PAGE showed the change of the Hb molecular weight(MW) after crosslinking.Gel chromatography showed that the poly Hb-P had a continuous distribution of molecular weight with the range from about 65,000 to 600,000 Dalton.The poly Hb-P solution provided a nornal oxygen carrying with 23.1 of P50 at pH 7.24 or 26.1 of P50 at pH7.24.

  5. Semi-Industrial Experimental Study of Preparation Ferronickel by Rotary Kiln Direct Reduction on Mangshi Silicate Nickel Ores in Yunnan%芒市硅酸镍矿回转窑直接还原制备镍铁半工业试验研究

    Institute of Scientific and Technical Information of China (English)

    肖军辉; 冯启明; 王振; 王德志

    2012-01-01

    The Mangshi silicate nickel crude ores in Yunnan contained Ni grade of 1. 02% , Fe grade of 8. 94% , and MgO grade of 31. 11 % , which belonged to the typical type of silicate nickel ore high in magnesium and low in iron. Because magnesium oxide content was rather high, according to the small test research results, in the roasting process adding CX accelerating agent and ZX addition agent by oneself research and development to improve reduction of nickel and enhance ferronickel conversion rate. Using the characteristic of both nickel and iron belonging to ferromagnetism metals and easy dissolving in oxide of iron, adding hematite as activating a-gent, providing activated carrier for forming ferronickel, and then improving the ferronickel product index. Semi-industrial experimental study was conducted with Φ1200 mm × 15000 mm rotary kiln to check the feasibility of separation and metallurgy combination flowsheet of direct reduction-gravity separation-magnetic separation to process Mangshi silicate nickel ores. The high-temperature zone was 1150 ~ 1200 ℃ in B sect, 950 ~ 1000 ℃ in C sect, roasting time was 90 min, dosage of coke was 20% , dosage of accelerator (CX) was 20% .dosage of additives (ZX) was 1% , dosage of hematite was 15% , after the roasting condition experiment of rotary kiln, the ferronickel product index was ideal. Under the roasting comprehensive condition, the rotary kiln 72 h continuous stable technological parameter was conducted to further check the stability of roasting condition and feasibility of technology, adopting gravity separation-magnetic separation technology recovery of ferronickel from roasting products and getting the whole technological process ferronickel product index: grade of nickel was 12. 29% , content of iron was 30.05% , recovery of nickel was 90. 99% . Therefore direct reduction-gravity separation-magnetic separation technology by rotary kiln had the favorable effect on processing the Mangshi silicate nickel ore type

  6. Health Gain by Salt Reduction in Europe: A Modelling Study

    NARCIS (Netherlands)

    Hendriksen, M.A.H.; Raaij, van J.M.A.; Geleijnse, J.M.; Breda, J.; Boshuizen, H.C.

    2015-01-01

    Excessive salt intake is associated with hypertension and cardiovascular diseases. Salt intake exceeds the World Health Organization population nutrition goal of 5 grams per day in the European region. We assessed the health impact of salt reduction in nine European countries (Finland, France, Irela

  7. Health gain by salt reduction in europe: a modelling study.

    Directory of Open Access Journals (Sweden)

    Marieke A H Hendriksen

    Full Text Available Excessive salt intake is associated with hypertension and cardiovascular diseases. Salt intake exceeds the World Health Organization population nutrition goal of 5 grams per day in the European region. We assessed the health impact of salt reduction in nine European countries (Finland, France, Ireland, Italy, Netherlands, Poland, Spain, Sweden and United Kingdom. Through literature research we obtained current salt intake and systolic blood pressure levels of the nine countries. The population health modeling tool DYNAMO-HIA including country-specific disease data was used to predict the changes in prevalence of ischemic heart disease and stroke for each country estimating the effect of salt reduction through its effect on blood pressure levels. A 30% salt reduction would reduce the prevalence of stroke by 6.4% in Finland to 13.5% in Poland. Ischemic heart disease would be decreased by 4.1% in Finland to 8.9% in Poland. When salt intake is reduced to the WHO population nutrient goal, it would reduce the prevalence of stroke from 10.1% in Finland to 23.1% in Poland. Ischemic heart disease would decrease by 6.6% in Finland to 15.5% in Poland. The number of postponed deaths would be 102,100 (0.9% in France, and 191,300 (2.3% in Poland. A reduction of salt intake to 5 grams per day is expected to substantially reduce the burden of cardiovascular disease and mortality in several European countries.

  8. Health Gain by Salt Reduction in Europe: A Modelling Study

    NARCIS (Netherlands)

    Hendriksen, M.A.H.; Raaij, van J.M.A.; Geleijnse, J.M.; Breda, J.; Boshuizen, H.C.

    2015-01-01

    Excessive salt intake is associated with hypertension and cardiovascular diseases. Salt intake exceeds the World Health Organization population nutrition goal of 5 grams per day in the European region. We assessed the health impact of salt reduction in nine European countries (Finland, France, Irela

  9. A study on limb reduction defects in six European regions

    NARCIS (Netherlands)

    Stoll, C; Calzolari, E; Cornel, M; GarciaMinaur, S; Garne, E; Nevin, N

    1996-01-01

    Limb reduction defects (LRD) gained especial attention after the thalidomide tragedy in 1962, LRD are common congenital malformations which present as obvious congenital anomalies recognized at birth, Therefore it might be assumed that they are well documented, However classification of LRDs is disp

  10. Biomimetic Drag Reduction Study on Herringbone Riblets of Bird Feather

    Institute of Scientific and Technical Information of China (English)

    Huawei Chen; Fugang Rao; Xiaopeng Shang; Deyuan Zhang; Ichiro Hagiwara

    2013-01-01

    Birds have gradually formed various excellent structures such as streamlined shape and hollow shaft of feather to improve their flying performance by millions of years of natural selection.As typical property of bird feather,herringbone riblets align along the shaft of each feather,which is caused by perfect link of barbs,especially for the primary and secondary feathers of wings.Such herringbone riblets of feather are assumed to have great impact on drag reduction.In this paper,microstructures of secondary feathers of adult pigeons are investigated by SEM,and their structural parameters are statistically obtained.Based on quantitative analysis of feather structure,novel biomimetic herringbone riblets with narrow smooth edge are proposed to reduce surface drag.In comparison with traditional microgroove riblets and other drag reduction structures,the drag reduction rate of the proposed biomimetic herringbone riblets is experimentally clarified up to 16%,much higher than others.Moreover,the drag reduction mechanism of herringbone riblets are also confirmed and exploited by CFD.

  11. Smoking reduction and biomarkers in two longitudinal studies

    DEFF Research Database (Denmark)

    Godtfredsen, Nina; Prescott, Eva; Vestbo, Jørgen

    2006-01-01

    a reduction in cigarettes per day of 50% or more without quitting were compared with continuing medium, heavy and light smokers (1-14 g/day) using linear regression. Sex (CCHS only), age, self-reported inhalation of smoke, duration of smoking, type of tobacco and amount smoked were included as covariates...

  12. A study on limb reduction defects in six European regions

    NARCIS (Netherlands)

    Stoll, C; Calzolari, E; Cornel, M; GarciaMinaur, S; Garne, E; Nevin, N

    1996-01-01

    Limb reduction defects (LRD) gained especial attention after the thalidomide tragedy in 1962, LRD are common congenital malformations which present as obvious congenital anomalies recognized at birth, Therefore it might be assumed that they are well documented, However classification of LRDs is disp

  13. Health gain by salt reduction in europe: a modelling study.

    Science.gov (United States)

    Hendriksen, Marieke A H; van Raaij, Joop M A; Geleijnse, Johanna M; Breda, Joao; Boshuizen, Hendriek C

    2015-01-01

    Excessive salt intake is associated with hypertension and cardiovascular diseases. Salt intake exceeds the World Health Organization population nutrition goal of 5 grams per day in the European region. We assessed the health impact of salt reduction in nine European countries (Finland, France, Ireland, Italy, Netherlands, Poland, Spain, Sweden and United Kingdom). Through literature research we obtained current salt intake and systolic blood pressure levels of the nine countries. The population health modeling tool DYNAMO-HIA including country-specific disease data was used to predict the changes in prevalence of ischemic heart disease and stroke for each country estimating the effect of salt reduction through its effect on blood pressure levels. A 30% salt reduction would reduce the prevalence of stroke by 6.4% in Finland to 13.5% in Poland. Ischemic heart disease would be decreased by 4.1% in Finland to 8.9% in Poland. When salt intake is reduced to the WHO population nutrient goal, it would reduce the prevalence of stroke from 10.1% in Finland to 23.1% in Poland. Ischemic heart disease would decrease by 6.6% in Finland to 15.5% in Poland. The number of postponed deaths would be 102,100 (0.9%) in France, and 191,300 (2.3%) in Poland. A reduction of salt intake to 5 grams per day is expected to substantially reduce the burden of cardiovascular disease and mortality in several European countries.

  14. Health Gain by Salt Reduction in Europe: A Modelling Study

    NARCIS (Netherlands)

    Hendriksen, M.A.H.; Raaij, van J.M.A.; Geleijnse, J.M.; Breda, J.; Boshuizen, H.C.

    2015-01-01

    Excessive salt intake is associated with hypertension and cardiovascular diseases. Salt intake exceeds the World Health Organization population nutrition goal of 5 grams per day in the European region. We assessed the health impact of salt reduction in nine European countries (Finland, France,

  15. Electroless reduction of silver chloride precipitates for the preparation of highly sensitive substrates for surface-enhanced infrared absorption (SEIRA) measurements.

    Science.gov (United States)

    Rao, Gadupudi Purna Chandra; Yang, Jyisy

    2015-01-01

    To prepare silver nanoparticles (AgNPs) on infrared-transmitting crystal for surface-enhanced infrared absorption (SEIRA) measurements, a new strategy is proposed and demonstrated using electroless reduction of preformed silver chloride (AgCl) particles. Silver chloride precipitates were formed using an additive of polyvinyl pyrrolidone (PVP) to vary the size and shape of the precipitates. After settling on germanium substrates, the preformed particles of AgCl were reduced electrolessly and spontaneously coagulated to AgNPs. The resulting AgNPs showed a multilayer structure, but the AgNPs were isolated, as shown by the lack of absorption-band distortion in the SEIRA measurements. Hence, the sensitivity and analyte-loading capacity for SEIRA measurements are improved significantly. To optimize the chemical deposition and electroless reduction method, we examined several parameters, including the concentrations of reagents during AgCl precipitation and the reaction time required in the deposition-reduction steps. We used para-nitrobenzoic acid (pNBA) to probe the intensity of the SEIRA effect for the prepared substrates. To better correlate the SEIRA performances with each variable, we examined the prepared substrates using a scanning electron microscope and SEIRA. The results indicate that two major morphologies of AgNPs are observed: nanoparticles and nanorods. The distributions of nanorods we observed were related to the procedures used to prepare the substrates. Based on SEIRA signals, we observed enhancement factors approaching three orders of magnitude compared to conventional transmission measurement. Also, based on the morphologies, the large signals were mainly caused by the formation of multilayers of non-percolated AgNPs.

  16. Reduction of Sn-Bearing Iron Concentrate with Mixed H2/CO Gas for Preparation of Sn-Enriched Direct Reduced Iron

    Science.gov (United States)

    You, Zhixiong; Li, Guanghui; Wen, Peidan; Peng, Zhiwei; Zhang, Yuanbo; Jiang, Tao

    2017-06-01

    The development of manufacturing technology of Sn-bearing stainless steel inspires a novel concept for using Sn-bearing complex iron ore via reduction with mixed H2/CO gas to prepare Sn-enriched direct reduced iron (DRI). The thermodynamic analysis of the reduction process confirms the easy reduction of stannic oxide to metallic tin and the rigorous conditions for volatilizing SnO. Although the removal of tin is feasible by reduction of the pellet at 1223 K (950 °C) with mixed gas of 5 vol pct H2, 28.5 vol pct CO, and 66.5 vol pct CO2 (CO/(CO + CO2) = 30 pct), it is necessary that the pellet be further reduced for preparing DRI. In contrast, maintaining Sn in the metallic pellet is demonstrated to be a promising way to effectively use the ore. It is indicated that only 5.5 pct of Sn is volatilized when the pellet is reduced at 1223 K (950 °C) for 30 minutes with the mixed gas of 50 vol pct H2, 50 vol pct CO (CO/(CO + CO2) = 100 pct). A metallic pellet (Sn-bearing DRI) with Sn content of 0.293 pct, Fe metallization of 93.5 pct, and total iron content of 88.2 pct is prepared as a raw material for producing Sn-bearing stainless steel. The reduced tin in the Sn-bearing DRI either combines with metallic iron to form Sn-Fe alloy or it remains intact.

  17. Reduction of Sn-Bearing Iron Concentrate with Mixed H2/CO Gas for Preparation of Sn-Enriched Direct Reduced Iron

    Science.gov (United States)

    You, Zhixiong; Li, Guanghui; Wen, Peidan; Peng, Zhiwei; Zhang, Yuanbo; Jiang, Tao

    2017-02-01

    The development of manufacturing technology of Sn-bearing stainless steel inspires a novel concept for using Sn-bearing complex iron ore via reduction with mixed H2/CO gas to prepare Sn-enriched direct reduced iron (DRI). The thermodynamic analysis of the reduction process confirms the easy reduction of stannic oxide to metallic tin and the rigorous conditions for volatilizing SnO. Although the removal of tin is feasible by reduction of the pellet at 1223 K (950 °C) with mixed gas of 5 vol pct H2, 28.5 vol pct CO, and 66.5 vol pct CO2 (CO/(CO + CO2) = 30 pct), it is necessary that the pellet be further reduced for preparing DRI. In contrast, maintaining Sn in the metallic pellet is demonstrated to be a promising way to effectively use the ore. It is indicated that only 5.5 pct of Sn is volatilized when the pellet is reduced at 1223 K (950 °C) for 30 minutes with the mixed gas of 50 vol pct H2, 50 vol pct CO (CO/(CO + CO2) = 100 pct). A metallic pellet (Sn-bearing DRI) with Sn content of 0.293 pct, Fe metallization of 93.5 pct, and total iron content of 88.2 pct is prepared as a raw material for producing Sn-bearing stainless steel. The reduced tin in the Sn-bearing DRI either combines with metallic iron to form Sn-Fe alloy or it remains intact.

  18. Setup Time Reduction On Solder Paste Printing Machine – A Case Study

    Directory of Open Access Journals (Sweden)

    Rajesh Dhake

    2013-06-01

    Full Text Available Lean manufacturing envisages the reduction of the seven deadly wastes referred to as MUDA. Setup time forms a major component of the equipment downtime. It leads to lower machine utilization and restricts the output and product variety. This necessitates the requirement for quick setups. Single Minute Exchange of Die philosophy (a lean manufacturing tool here after referred as “SMED” is one of the important tool which aims at quick setups driving smaller lot sizes, lower production costs, improve productivity in terms of increased output, increased utilization of machine and labor hours, make additional capacity available (often at bottleneck resources, reduce scrap and rework, and increase flexibility[3]. This paper focuses on the application of Single Minute Exchange of Die[1] and Quick Changeover Philosophy[2] for reducing setup time on Solder Past Printing Machine (bottleneck machine in a electronic speedo-cluster manufacturing company. The four step SMED philosophy was adopted to effect reduction in setup time. The initial step was gathering information about the present setup times and its proportion to the total productive time. A detailed video based time study of setup activities was done to classify them into external and internal setup activities in terms of their need (i.e. preparation, replacement or adjustment, time taken and the way these could be reduced, simplified or eliminated. The improvements effected were of three categories viz., mechanical, procedural and organizational. The paper concludes by comparing the present and proposed (implemented methods of setup procedures.

  19. A study of the process of Nd{sub 15} Fe{sub 77} B{sub 8} magnetic alloy preparation by calciothermic reduction diffusion (R/D); Estudo do processo de obtencao da liga magnetica Nd{sub 15} Fe{sub 77} B{sub 8} por reducao-difusao (R/D) calciotermica

    Energy Technology Data Exchange (ETDEWEB)

    Graca Guilherme, Eneida da; Paschoal, Jose O.A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

    1992-12-31

    In this work the manufacturing of Nd{sub 15}, Fe{sub 77}, B{sub 8} alloy powder for high-performance permanent magnets by reduction-diffusion process was investigated. The effect of variables such as the excess amount of neodymium oxide, the removal of calcium oxide by selective leaching and milling of alloy was examined. (author). 8 refs., 8 figs., 5 tab.s.

  20. Preparation, spectral and thermal studies of neodymium zirconyl oxalate hexahydrate

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, V.B.; Mehrotra, P.N. (Roorkee Univ. (India). Dept. of Chemistry)

    Neodymium zirconyl oxalate (NdZrOX) is prepared and characterized by chemical analysis and IR spectral studies. Its thermal decomposition was investigated using DTA, TG, DTG, x-ray diffraction and IR spectroscopy. Based on thermogravimetry and isothermal studies a probable mechanism for the decomposition is proposed. The decomposition proceeds mainly through three stages: dehydration between RT-413 K; decomposition of oxalate between 413-943 K; and decomposition of the carbonate between 1028-1235 K to give a mixed oxide. The IR spectra and x-ray diffraction studies are made for identification of the intermediates. X-ray diffraction studies of the end product indicates that it belongs to cubic crystal system.

  1. Response Surface Optimization for Process Parameters of LiFePO_4/C Preparation by Carbothermal Reduction Technology

    Institute of Scientific and Technical Information of China (English)

    杨克迪; 谭芳香; 王凡; 龙云飞; 文衍宣

    2012-01-01

    A statistically based optimization strategy is used to optimize the carbothermal reduction technology for the synthesis of LiFePO4/C using LiOH,FePO4 and sucrose as raw materials.The experimental data for fitting the response are collected by the central composite rotatable design(CCD).A second order model for the discharge ca-pacity of LiFePO4/C is expressed as a function of sintering temperature,sintering time and carbon content.The ef-fects of individual variables and their interactions are studied by a statistical analysis(ANOVA).The results show that the linear effects and the quadratic effects of sintering temperature,carbon content and the interactions among these variables are statistically significant,while those effects of sintering time are insignificant.Response surface plots for spatial representation of the model illustrate that the discharge capacity depends on sintering temperature and carbon content more than sintering time.The model obtained gives the optimized reaction parameters of sinter-ing temperature at 652.0 ℃,carbon content of 34.33 g?mol-1 and 8.48 h sintering time,corresponding to a dis-charge capacity of 150.8 mA·h·g-1.The confirmatory test with these optimum parameters gives the discharge ca-pacity of 147.2 and 105.1 mA·h·g-1 at 0.5 and 5 C,respectively.

  2. Health Gain by Salt Reduction in Europe: A Modelling Study

    OpenAIRE

    Hendriksen, Marieke A. H.; van Raaij, Joop M.A.; Geleijnse, Johanna M.; Joao Breda; Boshuizen, Hendriek C.

    2015-01-01

    Excessive salt intake is associated with hypertension and cardiovascular diseases. Salt intake exceeds the World Health Organization population nutrition goal of 5 grams per day in the European region. We assessed the health impact of salt reduction in nine European countries (Finland, France, Ireland, Italy, Netherlands, Poland, Spain, Sweden and United Kingdom). Through literature research we obtained current salt intake and systolic blood pressure levels of the nine countries. The populati...

  3. Iron Corrosion Observations: Pu(VI)-Fe Reduction Studies

    Energy Technology Data Exchange (ETDEWEB)

    Reed, Donald T. [Los Alamos National Laboratory; Swanson, Juliet S. [Los Alamos National Laboratory; Richmann, Michael K. [Los Alamos National Laboratory; Lucchini, Jean-Francois [Los Alamos National Laboratory; Borkowski, Marian [Los Alamos National Laboratory

    2012-09-11

    Iron and Pu Reduction: (1) Very different appearances in iron reaction products were noted depending on pH, brine and initial iron phase; (2) Plutonium was associated with the Fe phases; (3) Green rust was often noted at the higher pH; (4) XANES established the green rust to be an Fe2/3 phase with a bromide center; and (5) This green rust phase was linked to Pu as Pu(IV).

  4. Naval Survivability and Susceptibility Reduction Study-Surface Ship

    Science.gov (United States)

    2012-09-01

    magnetic steels  High- alloy steel  Corrosion resistant alloys 32  Titanium alloys  Aluminum alloys  Metal-based composite materials...the ferromagnetic signature. As ships are built under the influence of the Earth’s magnetic field [133], the ferrous materials used in the...techniques, the magnetic field of a ship can be reduced by passive and active means. The passive reduction could be achieved by using less ferrous

  5. Preparation of Nano-crystalline Tungsten Carbide Thin Film by Magnetron Sputtering and Their Electrocatalytic Property for PNP Reduction

    Institute of Scientific and Technical Information of China (English)

    Hua Jun ZHENG; Jian Guo HUANG; Chun An MA

    2005-01-01

    Nano-crystalline tungsten carbide thin films were deposited on Ni substrates by magnetron sputtering using WC as target material. The crystal structure and morphology of the thin films were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM).Electrochemical investigations showed that the electrode of the thin film exhibited higher electrocatalytic activity in the reaction of p-nitrophenol (PNP) reduction. FT-IR analysis indicated that p-aminophenol (PAP) was synthesized after two step reduction of PNP on nano-crystalline tungsten carbide thin film electrode.

  6. Preparation of FeO(OH Modified with Polyethylene Glycol and Its Catalytic Activity on the Reduction of Nitrobenzene with Hydrazine Hydrate

    Directory of Open Access Journals (Sweden)

    Ke Ying Cai

    2016-10-01

    Full Text Available Iron oxyhydroxide was prepared by dropping ammonia water to Fe(NO33.9H2O dispersed in polyethylene glycol (PEG 1000. The catalyst was characterized by X-ray powder diffraction, Fourier transform infrared spectroscopy and laser particle size analyzer. The results showed the catalyst modified with polyethylene glycol was amorphous. The addition of PEG during the preparation make the particle size of the catalyst was smaller and more uniform. The catalytic performance was tested in the reduction of nitroarenes to corresponding amines with hydrazine hydrate, and the catalyst showed excellent activity and stability. Copyright © 2016 BCREC GROUP. All rights reserved Received: 2nd February 2016; Revised: 26th April 2016; Accepted: 7th June 2016 How to Cite: Cai, K.Y., Liu, Y.S., Song, M., Zhou, Y.M., Liu, Q., Wang, X.H. (2016. Preparation of FeO(OH Modified with Polyethylene Glycol and Its Catalytic Activity on the Reduction of Nitrobenzene with Hydrazine Hydrate. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (3: 363-368 (doi:10.9767/bcrec.11.3.576.363-368 Permalink/DOI: http://doi.org/10.9767/bcrec.11.3.576.363-368

  7. Preparation, characterization and photoluminescent studies of Cr and Nd co-doped Ce:YAG compounds

    Energy Technology Data Exchange (ETDEWEB)

    Naik, S.R. [Department of Chemistry, Goa University, Goa 403206 (India); Shripathi, T. [UGC-DAE Consortium for Scientific Research, Khandwa Road, Indore 452017 (India); Salker, A.V., E-mail: sal_arun@rediffmail.com [Department of Chemistry, Goa University, Goa 403206 (India)

    2015-05-15

    Sol–gel autocombustion as an efficient method in the preparation of monophasic Cr and Nd co-doped Ce:YAG compounds has been demonstrated. A reduction in the formation temperature to 1000 °C as compared to the classical ceramic method has been effectively shown. Monophasic formation of the compounds has been confirmed from the X-ray diffraction study which is equally supported by the Raman spectroscopy. The TEM analysis confirms the formation of submicron sized particles (around 100 nm) which are equally supported by SEM micrographs revealing the granular morphology for the compounds. Photoluminescence (excitation) studies carried out for the compounds at 468, 341 and 685 nm display excellent emission intensity for the compounds with similar emission pattern pointing towards a common emission centre in all the three cases. Decrease in Ce{sup 3+} emission intensity for the Cr and Nd co-doped Ce:YAG is observed. Energy transfer mechanism is suggested for the lowering of emission intensity confirming the activity of Ce{sup 3+} as a sensitizer. - Highlights: • Nd and Cr co-doped Ce:YAG are prepared by the sol–gel autocombustion. • Monophasic preparation proves the method to be efficient. • Formation of particles around 100 nm is confirmed from TEM. • Singly doped Ce:YAG exhibits maximum emission intensity. • Energy transfer between ions in excited state is in co-doped samples.

  8. Preparation and biological studies of 68Ga-DOTA-alendronate

    Directory of Open Access Journals (Sweden)

    Ashraf Fakhari

    2016-07-01

    Full Text Available Objective(s: In line with previous research on the development of conjugated bisphosphonate ligands as new bone-avid agents, in this study, DOTA conjugated alendronate (DOTA-ALN was synthesized and evaluated after labeling with gallium-68 (68Ga.Methods: DOTA-ALN was synthesized and characterized, followed by 68Ga-DOTA-ALN preparation, using DOTA-ALN and 68GaCl3 (pH: 4-5 at 92-95°C for 10 min. Stability tests, hydroxyapatite assay, partition coefficient calculation,biodistribution studies, and imaging were performed on the developed agent in normal rats.Results: The complex was prepared with high radiochemical purity (>99% as depicted by radio thin-layer chromatography; specific activity: 310-320GBq/mmol after solid phase purification and was stabilized for up to 90 min with a logP value of -2.91. Maximum ligand binding (65% was observed in the presence of 50 mg of hydroxyapatite; a major portion of the activity was excreted through the kidneys. With the exception of excretory organs, gastrointestinal tract organs, including the liver, intestine, and colon, showed significant uptake; however, the bone uptake was low (

  9. Studies of silicon quantum dots prepared at different substrate temperatures

    Science.gov (United States)

    Al-Agel, Faisal A.; Suleiman, Jamal; Khan, Shamshad A.

    2017-03-01

    In this research work, we have synthesized silicon quantum dots at different substrate temperatures 193, 153 and 123 K at a fixed working pressure 5 Torr. of Argon gas. The structural studies of these silicon quantum dots have been undertaken using X-ray diffraction, Field Emission Scanning Electron Microscopy (FESEM) and High Resolution Transmission Electron Microscopy (HRTEM). The optical and electrical properties have been studied using UV-visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, Fluorescence spectroscopy and I-V measurement system. X-ray diffraction pattern of Si quantum dots prepared at different temperatures show the amorphous nature except for the quantum dots synthesized at 193 K which shows polycrystalline nature. FESEM images of samples suggest that the size of quantum dots varies from 2 to 8 nm. On the basis of UV-visible spectroscopy measurements, a direct band gap has been observed for Si quantum dots. FTIR spectra suggest that as-grown Si quantum dots are partially oxidized which is due exposure of as-prepared samples to air after taking out from the chamber. PL spectra of the synthesized silicon quantum dots show an intense peak at 444 nm, which may be attributed to the formation of Si quantum dots. Temperature dependence of dc conductivity suggests that the dc conductivity enhances exponentially by raising the temperature. On the basis above properties i.e. direct band gap, high absorption coefficient and high conductivity, these silicon quantum dots will be useful for the fabrication of solar cells.

  10. Preparation, structural and morphological studies of Ni doped titania nanoparticles.

    Science.gov (United States)

    Rajamannan, B; Mugundan, S; Viruthagiri, G; Shanmugam, N; Gobi, R; Praveen, P

    2014-07-15

    TiO2 nanoparticles doped with different weight percentages (4%, 8%, 12% and 16%) of nickel contents were prepared by a modified sol-gel method using Titanium tetra iso propoxide and nickel nitrate as precursors and 2-propanol as a solvent. X-ray diffraction studies show that the as prepared and annealed products show anatase structure with average particle sizes running between of 8 and 16 nm. FTIR results demonstrate the presence of strong chemical bonding at the interface of TiO2 nanoparticles. The optical properties of bare and doped samples were carried out using UV-DRS and photoluminescence measurements. The surface morphology and the element constitution of the nickel doped TiO2 nanoparticles were studied by scanning electron microscope attached with energy dispersive X-ray spectrometer arrangement. The non linear optical properties of the products were confirmed by Kurtz second harmonic generation (SHG) test and the output power generated by the nanoparticle was compared with that of potassium di hydrogen phosphate (KDP).

  11. Effects of molecular structures on reduction properties of formyl groups in chlorophylls and pheophytins prepared from oxygenic photosynthetic organisms.

    Science.gov (United States)

    Sadaoka, Kana; Kashimura, Shigenori; Saga, Yoshitaka

    2011-07-01

    Reduction of the 7-formyl groups in chlorophyll (Chl) b and its demetalated compound pheophytin (Phe) b was kinetically analyzed by using tert-butylamine-borane complex (t-BuNH(2)·BH(3)), and was compared with that of the 3-formyl groups in Chl d and Phe d. Reduction kinetics of the 7-formyl group in Chl b was similar to that in Phe b in dichloromethane containing 5mM t-BuNH(2)·BH(3). Little difference of the reduction kinetics of the 7-formyl groups between Chl b and Phe b was in sharp contrast to the reduction kinetics of the 3-formyl groups in Chl d and Phe d: the 3-formyl group in Phe d was reduced 5.3-fold faster than that in Chl d. The 7-formyl groups in Chl b and Phe b were reduced more slowly than the 3-formyl groups in Chl d and Phe d, respectively. The difference of the reactivity between the 3- and 7-formyl groups was in line with (13)C NMR measurements of chlorophyllous pigments, in which the chemical shifts of carbon atoms in the 7-formyl groups of Chl b and Phe b were high-field shifted compared with those in the 3-formyl groups of Chl d and Phe d, respectively. These indicate that the 7-formyl groups in chlorophyllous pigments were less reactive for reduction to the corresponding hydroxymethyl groups than the 3-formyl groups due to the difference in electronic states of the formyl groups in the A- and B-rings of the chlorin macrocycle. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. The anatomical study of transoral atlantoaxial reduction plate internal fixation

    Institute of Scientific and Technical Information of China (English)

    AI Fu-zhi; YIN Qing-shui; WANG Zhi-yun; XIA Hong; CHANG Yun-bing; WU Zeng-hui; LIU Jing-fa

    2006-01-01

    Objective:To study relevant anatomical features of the structures involved in transoral atlanto-axial reduction plate (TARP) internal fixation through transoral approach for treating irreducible atlanto-axial dislocation and providing anatomical basis for the clinical application of TARP.Methods: Ten fresh craniocervical specimens were microsurgically dissected layer by layer through transoral approach. The stratification of the posterior pharyngeal wall, the course of the vertebral artery, anatomical relationships of the adjacent structures of the atlas and axis, and the closely relevant anatomical parameters for TARP internal fixation were measured.Results: The posterior pharyngeal wall consisted of two layers and two interspaces: the mucosa, prevertebral fascia, retropharyngeal space, and prevertebral space. The range from the anterior edge of the foramen magnum to C3could be exposed by this approach. The thickness of the posterior pharyngeal wall was (3.6 ± 0.3) mm (ranging2.9-4.3 mm) at the anterior tubercle of C1,(6.1 ± 0.4) mm ( ranging 5.2-7.1 mm) at the lateral mass of C1 and (5.5±0.4) mm (ranging4.3-6.5 mm) at the central part of C2, respectively. The distance from the incisor tooth to the anterior tubercle of C1, C1 screw entry point, and C2 screw entry point was ( 82. 5 ± 7. 8 ) mm ( ranging 71.4-96. 2 mm), ( 90. 1 ± 3. 8 ) mm ( ranging82.2-96. 3 mm), and ( 89.0 ± 4.1 ) mm ( ranging 81.3-95.3 mm), respectively. The distance between the vertebral artery at the atlas and the midline was (25.2 ±2.3) mm (ranging 20.4-29.7 mm) and that between the vertebral artery at the axis and the midline was ( 18.4 ±2.6) mm ( ranging 13. 1-23.0 mm). The allowed width of the atlas and axis for exposure was (39. 4 ± 2. 2 ) mm( ranging 36.2-42.7 mm) and ( 39.0 ± 2. 1 ) mm ( ranging35.8-42. 3 mm), respectively. The distance (a) between the two atlas screw insertion points (center of anterior aspect of C1 lateral mass) was (31.4 ± 3.3 ) mm ( ranging25.4-36.6 mm

  13. A Theoretical Study on Reductive Debromination of Polybrominated Diphenyl Ethers

    Directory of Open Access Journals (Sweden)

    Xian-Fei Huang

    2012-07-01

    Full Text Available Recent progress has been made in the reductive debromination of polybrominated diphenyl ethers (PBDEs by nanoscale zero-valent iron (nZVI. To better understand the mechanism of this reaction, seven selected BDE congeners and their anions were investigated at the density functional theory (DFT level using four different methods, including B3LYP/6-31G(d, B3LYP/6-31+G(d, B3LYP/6-31G(d,p and B3LYP/6-311G(d,p. The cleaved C–Br bonds observed in the equilibrium structures of anionic PBDEs were adopted as the probe of the susceptible debromination position of PBDEs in the presence of nZVI, and the proposed major reaction pathways based on our calculations can satisfactorily conform to the reported experimental results. The debromination preference is theoretically evaluated as meta-Br > ortho-Br > para-Br. In addition, both the calculated frontier orbital energies and adiabatic electronic affinities were found to be highly related to their experimental reductive debromination rate constants. The highest linear regression coefficient was observed in the case using the energy of lowest unoccupied molecular orbital as the molecular descriptor obtained from B3LYP/6-31G(d (R2 = 0.961, n = 7 or B3LYP/6-31G(d,p (R2 = 0.961, n = 7. The results clearly showed the evidence of an electron transfer mechanism associated with this reductive debromination reaction.

  14. Reductive nitrosylation of Methanosarcina acetivorans protoglobin: A comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Ascenzi, Paolo, E-mail: ascenzi@uniroma3.it [Laboratorio Interdipartimentale di Microscopia Elettronica, Università Roma Tre, Via della Vasca Navale 79, I-00146 Roma (Italy); Istituto di Biochimica delle Proteine, CNR, Via Pietro Castellino 111, I-80131 Napoli (Italy); Pesce, Alessandra [Dipartimento di Fisica, Università di Genova, I-16146 Genova (Italy); Nardini, Marco; Bolognesi, Martino [Dipartimento di Bioscienze, Università di Milano, Via Celoria 26, I-20133 Milano (Italy); Ciaccio, Chiara; Coletta, Massimo [Dipartimento di Scienze Cliniche e Medicina Traslazionale, Università di Roma Tor Vergata, Via Montpellier 1, I-00133 Roma (Italy); Consorzio Interuniversitario di Ricerca in Chimica dei Metalli nei Sistemi Biologici, Piazza Umberto I 1, I-70121 Bari (Italy); Dewilde, Sylvia [Department of Biomedical Sciences, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp (Belgium)

    2013-01-25

    Highlights: ► Methanosarcina acetivorans is a strictly anaerobic non-motile methane-producing Archaea. ► M. acetivorans protoglobin binds preferentially O{sub 2} rather than CO. ► Reductive nitrosylation of ferric M. acetivorans protoglobin. ► Nitrosylation of ferrious M. acetivorans protoglobin. ► M. acetivorans protoglobin is a scavenger of RNS and ROS. -- Abstract: Methanosarcina acetivorans is a strictly anaerobic non-motile methane-producing Archaea expressing protoglobin (Pgb) which might either facilitate O{sub 2} detoxification or act as a CO sensor/supplier in methanogenesis. Unusually, M. acetivorans Pgb (MaPgb) binds preferentially O{sub 2} rather than CO and displays anticooperativity in ligand binding. Here, kinetics and/or thermodynamics of ferric and ferrous MaPgb (MaPgb(III) and MaPgb(II), respectively) nitrosylation are reported. Data were obtained between pH 7.2 and 9.5, at 22.0 °C. Addition of NO to MaPgb(III) leads to the transient formation of MaPgb(III)–NO in equilibrium with MaPgb(II)–NO{sup +}. In turn, MaPgb(II)–NO{sup +} is converted to MaPgb(II) by OH{sup −}-based catalysis. Then, MaPgb(II) binds NO very rapidly leading to MaPgb(II)–NO. The rate-limiting step for reductive nitrosylation of MaPgb(III) is represented by the OH{sup −}-mediated reduction of MaPgb(II)–NO{sup +} to MaPgb(II). Present results highlight the potential role of MaPgb in scavenging of reactive nitrogen and oxygen species.

  15. Teacher Attitudes About Standardized Testing and Test Preparation: A Case Study

    Science.gov (United States)

    Klager, Christopher R.

    This study looks at how science teachers' attitudes about standardized testing affect the types of test preparation practice they choose. Interviews, both before and after state testing, classroom observations during test preparation, and documents from test preparation contributed evidence used to create case studies about two teachers. Teacher attitudes related to pressure they felt to obtain high scores, test preparation ethics, and inexperience with state testing contributed to the decisions the teachers made about test preparation. Education for teachers about what test preparation practices are appropriate and the format of the test could help other teachers make informed decisions about test preparation practices.

  16. Studies of compressible shear flows and turbulent drag reduction

    Science.gov (United States)

    Orszag, S. A.

    1981-04-01

    Compressible shear flows and drag reduction were examined and three methods are addressed: (1) the analytical and numerical aspects of conformal mapping were summarized and a new method for computation of these maps is presented; (2) the computer code SPECFD for solution of the three dimensional time dependent Navier-Stokes equations for compressible flow on the CYBER 203 computer is described; (3) results of two equation turbulence modeling of turbulent flow over wavy walls are presented. A modified Jones-Launder model is used in two dimensional spectral code for flow in general wavy geometries.

  17. Reduction reactions in doped ceria ceramics studied by dilatometry

    DEFF Research Database (Denmark)

    Mogensen, G.; Mogensen, Mogens Bjerg

    1993-01-01

    Reduction of pure and doped CeO2 to CeO2-x is associated with an expansion. The behaviour of pure CeO2, Ce0.9Ca0.1O1.9, Ce0.8Ca0.2O1.8 and Ce0.6Gd0.4O1.8 at 1000-degrees-C in the oxygen partial pressure range from 0.21 atm to 10(-18) atm is described. The results show that even though the nominal...

  18. Study of barium bismuth titanate prepared by mechanochemical synthesis

    Directory of Open Access Journals (Sweden)

    Lazarević Z.Ž.

    2009-01-01

    Full Text Available Barium-bismuth titanate, BaBi4Ti4O15 (BBT, a member of Aurivillius bismuth-based layer-structure perovskites, was prepared from stoichiometric amounts of barium titanate and bismuth titanate obtained via mechanochemical synthesis. Mechanochemical synthesis was performed in air atmosphere in a planetary ball mill. The reaction mechanism of BaBi4Ti4O15 and the preparation and characteristics of BBT ceramic powders were studied using XRD, Raman spectroscopy, particle analysis and SEM. The Bi-layered perovskite structure of BaBi4Ti4O15 ceramic forms at 1100 °C for 4 h without a pre-calcination step. The microstructure of BaBi4Ti4O15 exhibits plate-like grains typical for the Bi-layered structured material and spherical and polygonal grains. The Ba2+ addition leads to changes in the microstructure development, particularly in the change of the average grain size.

  19. Studies on the oxygen reduction catalyst for zinc-air battery electrode

    Science.gov (United States)

    Wang, Xianyou; Sebastian, P. J.; Smit, Mascha A.; Yang, Hongping; Gamboa, S. A.

    In this paper, perovskite type La 0.6Ca 0.4CoO 3 as a catalyst of oxygen reduction was prepared, and the structure and performance of the catalysts was examined by means of IR, X-ray diffraction (XRD), and thermogravimetric (TG). Mixed catalysts doped, some metal oxides were put also used. The cathodic polarization curves for oxygen reduction on various catalytic electrodes were measured by linear sweep voltammetry (LSV). A Zn-air battery was made with various catalysts for oxygen reduction, and the performance of the battery was measured with a BS-9300SM rechargeable battery charge/discharge device. The results showed that the perovskite type catalyst (La 0.6Ca 0.4CoO 3) doped with metal oxide is an excellent catalyst for the zinc-air battery, and can effectively stimulate the reduction of oxygen and improve the properties of zinc-air batteries, such as discharge capacity, etc.

  20. Continuous preparation of nanoscale zero-valent iron using impinging stream-rotating packed bed reactor and their application in reduction of nitrobenzene

    Science.gov (United States)

    Jiao, Weizhou; Qin, Yuejiao; Luo, Shuai; Feng, Zhirong; Liu, Youzhi

    2017-02-01

    Nanoscale zero-valent iron (nZVI) was continuously prepared by high-gravity reaction precipitation through a novel impinging stream-rotating packed bed (IS-RPB). Reactant solutions of FeSO4 and NaBH4 were conducted into the IS-RPB with flow rates of 60 L/h and rotating speed of 1000 r/min for the preparation of nZVI. As-prepared nZVI obtained by IS-RPB were quasi-spherical morphology and almost uniformly distributed with a particle size of 10-20 nm. The reactivity of nZVI was estimated by the degradation of 100 ml nitrobenzene (NB) with initial concentration of 250 mg/L. The optimum dosage of nZVI obtained by IS-RPB was 4.0 g/L as the NB could be completely removed within 10 min, which reduced 20% compared with nZVI obtained by stirred tank reactor (STR). The reduction of NB and production of aniline (AN) followed pseudo-first-order kinetics, and the pseudo-first-order rate constants were 0.0147 and 0.0034 s-1, respectively. Furthermore, the as-prepared nZVI using IS-RPB reactor in this work can be used within a relatively wide range pH of 1-9.

  1. Reduction of electrical damage in specimens prepared using focused ion beam milling for dopant profiling using off-axis electron holography.

    Science.gov (United States)

    Cooper, David; Truche, Robert; Rouviere, Jean-Luc

    2008-04-01

    GaAs specimens containing p-n junctions have been prepared using focused ion beam (FIB) milling for examination using off-axis electron holography. By lowering the FIB operating voltage from 30 to 8 kV, we have shown a systematic reduction of the electrically 'inactive' thickness from 220 to 100 nm, resulting in a significant increase in the step in phase measured across the junctions as well as an improvement in the signal-to-noise ratio. We also show that the step in phase measured across the junctions can be influenced by the intensity of the electron beam.

  2. Reduction of electrical damage in specimens prepared using focused ion beam milling for dopant profiling using off-axis electron holography

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, David [CEA LETI-Minatec, 17 rue des Martyrs, 38054 Grenoble, Cedex 9 (France)], E-mail: david.cooper@cea.fr; Truche, Robert [CEA LETI-Minatec, 17 rue des Martyrs, 38054 Grenoble, Cedex 9 (France); Rouviere, Jean-Luc [CEA DRFMC-Minatec, 17 rue des Martyrs, 38054 Grenoble, Cedex 9 (France)

    2008-04-15

    GaAs specimens containing p-n junctions have been prepared using focused ion beam (FIB) milling for examination using off-axis electron holography. By lowering the FIB operating voltage from 30 to 8 kV, we have shown a systematic reduction of the electrically 'inactive' thickness from 220 to 100 nm, resulting in a significant increase in the step in phase measured across the junctions as well as an improvement in the signal-to-noise ratio. We also show that the step in phase measured across the junctions can be influenced by the intensity of the electron beam.

  3. Highly conductive graphene by low-temperature thermal reduction and in situ preparation of conductive polymer nanocomposites.

    Science.gov (United States)

    Yang, Liping; Kong, Junhua; Yee, Wu Aik; Liu, Wanshuang; Phua, Si Lei; Toh, Cher Ling; Huang, Shu; Lu, Xuehong

    2012-08-21

    Polydopamine-coated graphene oxide (DGO) films exhibit electrical conductivities of 11,000 S m(-1) and 30,000 S m(-1) upon vacuum annealing at 130 °C and 180 °C, respectively. Conductive poly(vinyl alcohol)/graphene and epoxy/graphene nanocomposites show low percolation thresholds due to the excellent dispersibility of the DGO sheets and their effective in situ reduction.

  4. Application of vacuum reduction and chlorinated distillation to enrich and prepare pure germanium from coal fly ash.

    Science.gov (United States)

    Zhang, Lingen; Xu, Zhenming

    2017-01-05

    Germanium, as strategic reserve metal, plays critical role in high-tech industry. However, a contradiction of increasing consumption and scarcity of germanium resource is becoming more and more prominent. This paper proposed an integrated process to recycle germanium from coal fly ash. This technological process mainly consisted of two procedures: vacuum reduction with the purposes of enriching germanium and chlorinated distillation with the purposes of purifying germanium. Several highlights are summarized as follows: (i) Separation principle and reaction mechanism were discussed to understand this integrated process. (ii) Optimum designs and product analysis were developed to guide industrial recycling. The appropriate parameters for vacuum reduction process on the basis of response surface methodology (RSM) were 920.53°C and 259.63Pa, with 16.64wt.% reductant, and for the chlorinated distillation process, adding 8mol/l HCl and L/S 7, 8wt.% MnO2. The global recovery rate of germanium was 83.48±0.36% for the integrated process. (iii) This process overcomes the shortages of traditional process and shows its efficiency and environmental performance. It is significant in accordance with the "Reduce, Reuse and Recycle Principle" for solid waste and further provides a new opportunity for germanium recovery from waste by environment-friendly way.

  5. Systematic study on the preparation of BSA nanoparticles.

    Science.gov (United States)

    Galisteo-González, F; Molina-Bolívar, J A

    2014-11-01

    Albumins, in the form of nanoparticles, are increasingly used as drug carriers in the medical field, and the size effect of these nanomaterials is of major importance since it may affect their bioavailability and the in vivo behaviour after intravenous injection. This research provides a comprehensive study on the preparation of BSA nanoparticles, based on a simple coacervation method, with suitable size, size distribution, and surface charge for drug-delivery applications. Numerous experimental variables were examined in order to characterize their impact on nanoparticle size, distribution, electrophoretic mobility, and yield. Particle size was controlled by adjusting self-assembly phenomena of the protein molecules, which was affected by preparation conditions including BSA content, pH, and ionic strength (a parameter that strongly influences nanoparticle formation but surprisingly has not been previously studied in detail). Small particles with a narrow size distribution were obtained under experimental conditions where the repulsion between BSA molecules was high, i.e. at pH values far from the isoelectric point of the protein and low salt concentration. Changes in temperature, volume, and rate of addition of the dehydrating agent (ethanol) also affect nanoparticle characteristics, as they influence the nucleation rate and particle growth. The effect of these experimental conditions on the quantity of protein still dissolved in the aqueous phase after desolvation (i.e. the yield of BSA nanoparticles) was also studied. Nanoparticles surface charge was modulated with the extension of cross-linking. Finally, long-term colloidal stability of samples was evaluated after 2 months of storage.

  6. Experimental study on solid state reduction of chromite with rising temperature

    Energy Technology Data Exchange (ETDEWEB)

    Kekkonen, M.; Syynimaa, A.; Holappa, L.

    1998-07-01

    The solid state reduction of preoxidized sintered chromite pellets, raw pellets, process pellets and lumpy ores have been studied with rising temperature 700-1520 deg C under CO-atmosphere in order to better simulate the conditions in the upper part of a real submerged arc furnace. According to the reduction degree curves the reduction behaviour of chromite pellets seems to be similar. The reduction rate was slow at the beginning but increased rapidly when the temperature reached about 1000 deg C. The final reduction degree was highest in the case of process pellets and lowest in the case of raw pellet. In the case of preoxidized pellets there was not much difference of the reduction rate and final reduction degree between different oxidation states. In the case of lumpy ores the reduction rate and the final reduction degree was much lower compared to the pellets. Optical photographs, phase and microanalysis show that the reduction has proceeded further in the surface of the samples and confirmed also that the reduction degree remained lower in the case of raw pellet and lumpy ores which was also seen from the reduction degree curves. According to the experiments in the case of preoxidized pellets the effect of oxidation state on the reduction rate was not observed due to small difference in the oxidation state of the samples. But when comparing the reduction of preoxidized pellets and unoxidised raw pellet we can say that preoxidation promotes the reduction. The final reduction degree of the raw pellet remained lower than in the case of preoxidized pellets. (orig.)

  7. Kinetic Study of Np(Ⅵ) Reduction With Tert-butyl Hydrazine

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Tert-butyl hydrazine(TBH) is a new salt free reductant, it can effectively reduce Np(Ⅵ) to Np(Ⅴ) but reduce Pu(Ⅳ)very slowly. Further more, it has the highest ratio of rate constant for Np(Ⅵ) reduction to the rate constant for Pu(Ⅳ) reduction in hydrazine derivatives, so it’s a promising reductant to separate Np, Pu effectively,Reduction kinetic study of the reaction in nitric acid is performed by spectrophotometry. The effect of some factors such as concentration of TBH, HNO3, Np(Ⅵ) and temperature on the redox

  8. Effects of three types of retirement preparation program: A qualitative study of civil servants in Brazil

    NARCIS (Netherlands)

    Leandro-França, C.; van Solinge, H.; Henkens, K.; Giardini Murta, S.

    2016-01-01

    Studies on the effectiveness of retirement planning programs are relatively scarce. Retirement preparation and planning programs may assist individuals to smooth the transition to retirement and subsequent adjustment. This qualitative study examines the effects of three retirement preparation progra

  9. Preparing tomorrow's health sciences librarians: feasibility and marketing studies.

    Science.gov (United States)

    Moran, B B; Jenkins, C G; Friedman, C P; Lipscomb, C E; Gollop, C J; Moore, M E; Morrison, M L; Tibbo, H R; Wildemuth, B M

    1996-10-01

    The University of North Carolina at Chapel Hill is devising and evaluating five curricular models designed to improve education for health sciences librarianship. These models fit into a continual learning process from the initial professional preparation to lifelong learning opportunities. Three of them enhance existing degree and certificate programs in the School of Information and Library Science (SILS) with a health sciences specialization, and two are new programs for working information professionals. The approaches involve partnerships among SILS, the Health Sciences Library, and the program in Medical Informatics. The planning process will study the feasibility of the proposed programs, test the marketability of the models to potential students and employers, and make recommendations about implementation.

  10. Efficacy of oral administration of lactic acid bacteria isolated from cocoa in a fermented milk preparation: reduction of colitis in an experimental rat model.

    Science.gov (United States)

    Dos Santos, T F; Melo, T A; Santos, D S; Rezende, R P; Dias, J C T; Romano, C C

    2016-07-29

    We investigated the probiotic potential of lactic acid bacteria (LAB) obtained from cocoa fermentation using an experimental rat model of colitis. Cocoa beans were collected from fermentation boxes every 12 h for 5 days to isolate the microorganisms. Strains were isolated by serial dilution and plating on MRS agar. Gram-positive and catalase-negative rods were subjected to DNA extraction, polymerase chain reaction, and sequencing. Ten strains were randomly pooled and used to prepare a fermented milk drink that was used to treat the experimental colitis. A parallel group was treated with a single strain drink. Serum concentrations of cytokines and IgA, total and differential counts of blood leukocytes, and histological appearance were compared with the untreated control colitis group. Eighty strains of LAB were identified as Lactobacillus fermentum (68) and Lactobacillus plantarum (12). The multi-strain LAB pool significantly reduced the total number of leukocytes. There was a significant reduction in the percentage of neutrophils and monocytes compared with the control colitis group. IFN-γ concentration was downregulated in animals treated with the LAB pool. IL-10 and IgA increased significantly in the group treated with the strains. Histological analysis showed that the LAB pool reduced the inflammatory infiltrate and restored tissue architecture. The group treated with the single strain LAB drink (L. fermentum) showed no signs of inflammation remission. The results confirm the probiotic action of cocoa-derived LAB in the treatment of experimental colitis. Studies using isogenic models and humans will clarify the mechanisms of immune response modulation in inflammatory bowel disease.

  11. Preparation and characterization of TiO2/acid leached serpentinite tailings composites and their photocatalytic reduction of chromium(VI).

    Science.gov (United States)

    Sun, Zhiming; Zheng, Liming; Zheng, Shuilin; Frost, Ray L

    2013-08-15

    Composite TiO2/acid leached serpentine tailings (AST) were synthesized through the hydrolysis-deposition method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), Fourier-transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and surface area measurement (BET). The XRD analysis showed that TiO2 coated on the surface of acid leached serpentine tailings was mixed crystal phases of rutile and anatase, the grain size of which is 10-30 nm. SEM, TEM, and EDS analysis exhibited that nano-TiO2 particles were deposited on the surface and internal cavities of acid leaching serpentine tailings. The XPS and FT-IR analysis demonstrated that the coating process of TiO2 on AST was a physical adsorption process. The large specific surface area, porous structure, and plentiful surface hydroxyl group of TiO2/AST composite resulted in the high adsorption capacity of Cr(VI). The experimental results demonstrated that initial concentration of Cr(VI), the amount of the catalyst, and pH greatly influenced the removal efficiency of Cr(VI). The removal kinetics of Cr(VI) at a relative low initial concentration was fitted well with Langmuir-Hinshelwood kinetics model with R(2) value of about unity. The as-prepared composites exhibited strong adsorption and photocatalytic capacity for the removal of Cr(VI), and the possible photocatalytic reduction mechanism was studied. The photodecomposition of Cr(VI) was as high as 95% within 2h, and the reusability of the photocatalysis was proven.

  12. Study of nonisothermal reduction of iron ore-coal/char composite pellet

    Science.gov (United States)

    Dutta, S. K.; Ghosh, A.

    1994-01-01

    Cold-bonded composite pellets, consisting of iron ore fines and fines of noncoking coal or char, were prepared by steam curing at high pressure in an autoclave employing inorganic binders. Dry compressive strength ranged from 200 to 1000 N for different pellets. The pellets were heated from room temperature to 1273 K under flowing argon at two heating rates. Rates of evolution of product gases were determined from gas Chromatographie analysis, and the temperature of the sample was monitored by thermocouple as a function of time during heating. Degree of reduction, volume change, and compressive strength of the pellets upon reduction were measured subsequently. Degree of reduction ranged from 46 to 99 pct. Nonisothermal devolatilization of coal by this procedure also was carried out for comparison. It has been shown that a significant quantity (10 to 20 pct of the pellet weight) of extraneous H2O and CO2 was retained by dried pellets. This accounted for the generation of additional quantities of H2 and CO during heating. Carbon was the major reductant, but reduction by H2 also was significant. Ore-coal and ore-char composites exhibited a comparable degree of reduction. However, the former showed superior postreduction strength due to a smaller amount of swelling upon reduction.

  13. Preparation of {sup 123}l and {sup 131}l mlBG by ascorbate reduction: A faster, safer method.

    Energy Technology Data Exchange (ETDEWEB)

    Baker, R.J. [Prince of Wales Hospital, Randwick, NSW, (Australia). Department of Nuclear Medicine

    1997-09-01

    Full text: Meta-iodobenzylguanidine labelled with {sup 123}l or {sup 131}l has been prepared in a number of hospital radiopharmacies by the method of van Dormalen and Janssen (Method 1), which uses a copper catalysed exchange reaction accomplished by heating at 140 degree C in a heavy walled glass vial. The product is purified by passage through a small anion exchange column to remove unreacted iodine. More recently, the method of Rossouw (Method 2) has become available which utilizes ascorbic acid and copper (II) ions to effect the iodination at 100 deg C. Since the latter method has a number of potential advantages, the object of this work was to compare the results obtained from each method under conditions of routine preparation. Analysis of preparations using Method 1 gave the following results: {sup 131}l, yield 89.3 {+-} 10.4% (n = 54); {sup 123}l, yield 85.5 {+-} 10.6% (n = 5). The radiochemical purity was determined by both chromatography on Whatman No.1 / butanol, acetic acid, water (60:15:25) and cellulose acetate electrophoresis with the following results (mean values from both techniques): {sup 131}l-mlBG 99.8 {+-} 0.1%;{sup 131}l- iodine 0.2 {+-} -0.1%. For {sup 123}l, {sup 123}l-mlBG 99.2 {+-} 0.2%; {sup 123}l-iodine 0.6 {+-} 0.2%. When prepared by Method 2, the results were: {sup 131}I, yield 86.0 {+-} 9.8% (n = 5); {sup 123}l, yield 97.0 {+-} 5.0% (n = 6). Radiochemical analyses were as follows: {sup 131}l-mlBG 98.9 {+-} 0.1%;{sup 131}l-iodine 1.0 {+-} 0.2%. For {sup 123}l, {sup 123}l-mlBG 97.8 {+-} 0.7%; {sup 123}l-iodine 2.1 {+-} 0.6%. It is concluded that although Method 2 resulted in products of slightly lower purity, the small increase in free iodide for both radionuclides can be tolerated in view of the routine use of thyroid blockade with Lugol`s solution. This method is much preferred as it removes the risk of explosion during the heating step. It is also considerably faster and reduces the chance of spillage as there is no need for passage

  14. Electrochemical preparation of nitrogen-doped graphene quantum dots and their size-dependent electrocatalytic activity for oxygen reduction

    Indian Academy of Sciences (India)

    Dhanraj B Shinde; Vishal M Dhavale; Sreekumar Kurungot; Vijayamohanan K Pillai

    2015-04-01

    Here we report a remarkable transformation of nitrogen-doped multiwalled carbon nanotubes (MWCNTs) to size selective nitrogen-doped graphene quantum dots (N-GQDs) by a two-step electrochemical method. The sizes of the N-GQDs strongly depend on the applied anodic potential, moreover increasing potential resulted in a smaller size of N-GQDs. These N-GQDs display many unusual size-dependant optoelectronic (blue emission) and electrocatalytic (oxygen reduction) properties. The presence of N dopants in the carbon framework not only causes faster unzipping of MWCNTs but also provides more low activation energy site for enhancing the electrocatalytic activity for technologically daunting reactions like oxygen reduction. The smaller size of N-GQDs has shown better performance as compared to the large N-GQDs. Interestingly, N-GQDs-3 (size = 2.5 ± 0.3 nm, onset potential = 0.75 V) show a 30-mV higher positive onset potential shift compared to that of N-GQDs-2 (size = 4.7 ± 0.3 nm, onset potential = 0.72 V) and 70 mV than that of N-GQDs-1 (size = 7.2 ± 0.3, onset potential = 0.68 V) for oxygen reduction reaction (ORR) in a liquid phase. These result in the size-dependent electrocatalytic activity of N-GQDs for ORR as illustrated by the smaller sized N-GQDs (2.5 ± 0.3 nm) undoubtedly promising metal-free electrocatalysts for fuel cell applications.

  15. Properties of highly crystalline NiO and Ni nanoparticles prepared by high-temperature oxidation and reduction

    Science.gov (United States)

    Feygenson, Mikhail; Kou, Angela; Kreno, Lauren E.; Tiano, Amanda L.; Patete, Jonathan M.; Zhang, Fen; Kim, Moo Sung; Solovyov, Vyacheslav; Wong, Stanislaus S.; Aronson, Meigan C.

    2010-01-01

    We describe here the use of high-temperature oxidation and reduction to produce highly crystalline nanoparticles of Ni and NiO. Starting with an amorphous Ni powder, we demonstrate that oxidation at 900°C produces faceted NiO nanocrystals with sizes ranging from 20 to 60 nm. High-resolution transmission electron microscopy measurements indicate near-perfect atomic order, truncated by (200) surfaces. Magnetization measurements reveal that the Néel temperature of these NiO nanoparticles is 480 K, substantially reduced by finite-size effects from the bulk value of 523 K. The magnetization of these faceted NiO nanoparticles does not saturate in fields as large as 14 T while a loop offset is observed which increases from 1000 Oe at 300 K to its maximum value of 3500 Oe at 50 K. We have used high-temperature reduction to transform the faceted NiO nanoparticles into highly ordered Ni nanoparticles, with a Curie temperature of 720 K and blocking temperatures in excess of 350 K. Subsequent efforts to reoxidize these Ni nanoparticles into the core-shell morphology found that the Ni nanoparticles are much more resistant to oxidation than the original Ni powder, perhaps due to the relative crystalline perfection of the former. At 800°C , an unusual surface roughening and subsequent instability was observed, where 50-nm-diameter NiO rods grow from the Ni surfaces. We have demonstrated that high-temperature oxidation and reduction in Ni and NiO are both reversible to some extent and are highly effective for creating the highly crystalline nanomaterials required for applications such as exchange-bias devices.

  16. Properties of Highly Crystalline NiO and Ni Nanoparticles Prepared by High-temperature Oxidation and Reduction

    Energy Technology Data Exchange (ETDEWEB)

    Feygenson, M.; Kou, A.; Kreno, L.E.; Tiano, A.L.; Patete, J.M.; Zhang, F.; Kim, M.S.; Solovyov, V.; Wong, S.S.; Aronson, M.C.

    2010-01-26

    We describe here the use of high-temperature oxidation and reduction to produce highly crystalline nanoparticles of Ni and NiO. Starting with an amorphous Ni powder, we demonstrate that oxidation at 900 C produces faceted NiO nanocrystals with sizes ranging from 20 to 60 nm. High-resolution transmission electron microscopy measurements indicate near-perfect atomic order, truncated by (200) surfaces. Magnetization measurements reveal that the Neel temperature of these NiO nanoparticles is 480 K, substantially reduced by finite-size effects from the bulk value of 523 K. The magnetization of these faceted NiO nanoparticles does not saturate in fields as large as 14 T while a loop offset is observed which increases from 1000 Oe at 300 K to its maximum value of 3500 Oe at 50 K. We have used high-temperature reduction to transform the faceted NiO nanoparticles into highly ordered Ni nanoparticles, with a Curie temperature of 720 K and blocking temperatures in excess of 350 K. Subsequent efforts to reoxidize these Ni nanoparticles into the core-shell morphology found that the Ni nanoparticles are much more resistant to oxidation than the original Ni powder, perhaps due to the relative crystalline perfection of the former. At 800 C, an unusual surface roughening and subsequent instability was observed, where 50-nm-diameter NiO rods grow from the Ni surfaces. We have demonstrated that high-temperature oxidation and reduction in Ni and NiO are both reversible to some extent and are highly effective for creating the highly crystalline nanomaterials required for applications such as exchange-bias devices.

  17. Preparation of conductive film via a low temperature synthesis that enables simultaneous nitrogen doping and reduction of graphene oxide

    Science.gov (United States)

    Bhattacharyya, Tamoghna

    2017-08-01

    A low temperature (‒78 °C), one-pot synthesis that enables the simultaneous reduction of graphene oxide (G-O) and nitrogen doping of reduced graphene oxide (rG-O) is described. The method facilitates the effective removal of oxygen-containing functional groups in the G-O and introduces both ‘graphitic’ and ‘pyridinic’ nitrogen up to 4% in the corresponding product. The N-doped materials displayed relatively high powder electrical conductivities (up to 2.5  ×  103 S m-1).

  18. Microwave Sintering of W-15Cu Ultrafine Composite Powder Prepared by Spray Drying & Calcining-continuous Reduction Technology

    Institute of Scientific and Technical Information of China (English)

    SHU Jingping; SHI Xiaoliang; WANG Shuwei; YANG Xingyong; ZHANG Qiaoxin; WANG Yufu

    2011-01-01

    The effects of microwave sintering and conventional H2 sintering on the microstructure and properties of W-l5Cu alloy using ultrafine W-15Cu composite powder fabricated by spray drying & calcining-continuous reduction technology were investigated. In comparison to the conventional H2 sintering processing, microwave sintefing to W-15Cu can be achieved at lower sintefing temperature and shorter sintering time. Furthermore, higher performances in microwave sintered compacts were obtained, but high microwave sintering temperature or long microwave sintering time could result in coarser microstructures.

  19. Quantitative analysis of plasma proteins in whole blood-derived fresh frozen plasma prepared with three pathogen reduction technologies.

    Science.gov (United States)

    Larrea, Luis; Ortiz-de-Salazar, María-Isabel; Martínez, Patricia; Roig, Roberto

    2015-06-01

    Several plasma pathogen reduction technologies (PRT) are currently available. We evaluated three plasma PRT processes: Cerus Amotosalen (AM), Terumo BCT riboflavin (RB) and Macopharma methylene blue (MB). RB treatment resulted in the shortest overall processing time and in the smallest volume loss (1%) and MB treatment in the largest volume loss (8%). MB treatment retained the highest concentrations of factors II, VII, X, IX, Protein C, and Antithrombin and the AM products of factor V and XI. Each PRT process evaluated offered distinct advantages such as procedural simplicity and volume retention (RB) and overall plasma protein retention (MB).

  20. Preparation of Cu@Cu₂O Nanocatalysts by Reduction of HKUST-1 for Oxidation Reaction of Catechol.

    Science.gov (United States)

    Jang, Seongwan; Yoon, Chohye; Lee, Jae Myung; Park, Sungkyun; Park, Kang Hyun

    2016-11-02

    HKUST-1, a copper-based metal organic framework (MOF), has been investigated as a catalyst in various reactions. However, the HKUST-1 shows low catalytic activity in the oxidation of catechol. Therefore, we synthesized Fe₃O₄@HKUST-1 by layer-by layer assembly strategy and Cu@Cu₂O by reduction of HKUST-1 for enhancement of catalytic activity. Cu@Cu₂O nanoparticles exhibited highly effective catalytic activity in oxidation of 3,5-di-tert-butylcatechol. Through this method, MOF can maintain the original core-shell structure and be used in various other reactions with enhanced catalytic activity.

  1. Investigation into feed preparation for regulatory fish metabolism studies.

    Science.gov (United States)

    Goeritz, Ina; Atorf, Cornelia; Whalley, Paul; Seymour, Paul; Klein, Michael; Schlechtriem, Christian

    2014-02-01

    Test diets used in fish metabolism studies for regulatory purposes must be homogenously fortified with the radiolabelled test substance and stable with respect to leaching. Standard fish food, as used in commercial fish farming, should also be used in fish metabolism studies. Therefore, suitable spiking and coating procedures are required to ensure the correct dosing of the fish during the experiment. Methods for the homogeneous, safe and efficient application of radiolabelled test items to the surface of commercial feeding pellets were developed. Leaching studies showed that test items of low lipophilicity applied to feeding pellets need to be stabilised, to reduce the risk of significant losses prior to ingestion by the fish. Coating of solvent-spiked pellets with calcium alginate was shown to reduce leaching losses of water-soluble test items significantly. Alternatively, commercial feeding pellets can be coated with alginate or vegetable oil fortified with a radiolabelled test item also leading to sufficiently stabilised test diets. Experimental conditions, such as the water temperature, may have a significant effect on the leaching behaviour of the test items. A detailed description of different spiking and coating procedures for the preparation of experimental diets suitable for fish metabolism studies is provided. © 2013 Society of Chemical Industry.

  2. Strategies of Successful Poverty Reduction: Case Studies of Tanzania and Zambia

    Science.gov (United States)

    2015-03-01

    SUCCESSFUL POVERTY REDUCTION: CASE STUDIES OF TANZANIA AND ZAMBIA by Jacqueline A. Natter March 2015 Thesis Co-Advisors: Robert E. Looney...March 2015 Master’s Thesis 4. TITLE AND SUBTITLE 5. FUNDING NUMBERS S1RA 1EGIES OF SUCCESSF1JL POVERTY REDUCTION: CASE STUDIES OF TANZANIA AND...growth in the 21st century, Tanzania has been able to translate that growth into poverty reduction while Zambia has not. A contextual picture of the two

  3. Impact of Overlapping Fe/TiO2 Prepared by Sol-Gel and Dip-Coating Process on CO2 Reduction

    Directory of Open Access Journals (Sweden)

    Akira Nishimura

    2016-01-01

    Full Text Available Fe-doped TiO2 (Fe/TiO2 film photocatalyst was prepared by sol-gel and dip-coating process to extend its photoresponsivity to the visible spectrum. To promote the CO2 reduction performance with the photocatalyst, some types of base materials used for coating Fe/TiO2, which were netlike glass fiber and Cu disc, were investigated. The characterization of prepared Fe/TiO2 film coated on netlike glass fiber and Cu disc was analyzed by SEM and EPMA. In addition, the CO2 reduction performance of Fe/TiO2 film coated on netlike glass disc, Cu disc, and their overlap was tested under a Xe lamp with or without ultraviolet (UV light, respectively. The results show that the concentration of produced CO increases by Fe doping irrespective of base material used under the illumination condition with UV light as well as that without UV light. Since the electron transfer between two overlapped photocatalysts is promoted, the peak concentration of CO for the Fe/TiO2 double overlapping is approximately 1.5 times as large as the Fe/TiO2 single overlapping under the illumination condition with UV light, while the promotion ratio is approximately 1.1 times under that without UV light.

  4. Morphological alteration and exceptional magnetic properties of air-stable FeCo nanocubes prepared by a chemical reduction method

    Energy Technology Data Exchange (ETDEWEB)

    Chokprasombat, K., E-mail: komkrich28@gmail.com [School of Physics, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand); Harding, P. [Molecular Technology Research Unit, School of Science, Walailak University, Nakhon Si Thammarat 80161 (Thailand); Pinitsoontorn, S. [Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Maensiri, S. [School of Physics, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand)

    2014-11-15

    FeCo nanocubes are of great interest due to their outstanding magnetic properties and larger contact area compared to the spherical particles. Herein, the FeCo nanocubes could be obtained by the reduction of metal ions by hydrazine hydrate under a concentrated basic condition. It was found that shape of the FeCo nanocubes varied from cubic with a mean edge length of 130±3 nm to polyhedron (diameter around 500–700 nm) depending on the concentration of using polymer. A lot of irregular nanoplates were also obtained when used the excessive polymer. In addition, the as-synthesized particles were air-stable which might be related to the formation of thin polymer shells on particle surfaces. The FeCo nanocubes also possessed exceptional magnetic properties at room temperature, including a very high saturation magnetization (217.14 emu/g) and low coercivity (85.95 Oe). - Highlights: • We report the synthesis of FeCo nanocubes by a chemical reduction method. • Shape of the particles clearly depended on the amount of polymer used. • The particles were air-stable and possessed excellent magnetic properties.

  5. Evaluation of research methods to study domestic food preparation

    NARCIS (Netherlands)

    Bongoni, R.; Verkerk, R.; Dekker, M.; Steenbekkers, B.

    2015-01-01

    Purpose – Domestic preparation practices influence the sensory properties and nutritional composition of food products. Information on the variability in actual domestic preparation practices is needed to assess the influence of applied conditions on the sensory and nutritional quality of food. The

  6. Evaluation of research methods to study domestic food preparation

    NARCIS (Netherlands)

    Bongoni, R.; Verkerk, R.; Dekker, M.; Steenbekkers, B.

    2015-01-01

    Purpose – Domestic preparation practices influence the sensory properties and nutritional composition of food products. Information on the variability in actual domestic preparation practices is needed to assess the influence of applied conditions on the sensory and nutritional quality of food. The

  7. Experimental Study on a Tuned-Mass Damper of Offshore for Vibration Reduction

    Science.gov (United States)

    Wu, Qiong; Zhao, Xilu; Zheng, Rencheng

    2016-09-01

    With the development of industry, oceanic oil production is one of the most important energy resources. Normally, offshore platform, located in the hostile environment, is easily subjected to unstable environmental loading, such as wind, wave, ice, and earthquake, and it becomes a critical problem to ensure the stability of offshore platform for safely engineering operations. In recent years, tuned-mass damper (TMD) technology has been adopted to reduce vibrations from wind and earthquake influences. Due to the complexity of earthquake excitations, most of researchers were focused on controlling response of structures under wind loads; however, less attention has been put on controlling earthquake response. Therefore, this study concentrates on the seismic reduction of offshore platform by application of a TMD system, and a comprehensively experimental study was processed to validate its effectiveness exposed to different earthquake. A 4-column offshore platform was built according to the actual size of approximately 1:200 ratios, and a TMD system was prepared for the experiment. By the different performance analyses, experimental results indicated that the proposed TMD system can effectively suppress the earthquake stimulus and keep the stability of offshore platform.

  8. Enhanced Oral Delivery of Docetaxel Using Thiolated Chitosan Nanoparticles: Preparation, In Vitro and In Vivo Studies

    Science.gov (United States)

    Saremi, Shahrooz; Kebriaeezadeh, Abbas; Ostad, Seyed Nasser; Atyabi, Fatemeh

    2013-01-01

    The aim of this study was to evaluate a nanoparticulate system with mucoadhesion properties composed of a core of polymethyl methacrylate surrounded by a shell of thiolated chitosan (Ch-GSH-pMMA) for enhancing oral bioavailability of docetaxel (DTX), an anticancer drug. DTX-loaded nanoparticles were prepared by emulsion polymerization method using cerium ammonium nitrate as an initiator. Physicochemical properties of the nanoparticles such as particle size, size distribution, morphology, drug loading, and entrapment efficiency were characterized. The pharmacokinetic study was carried out in vivo using wistar rats. The half-life of DTX-loaded NPs was about 9 times longer than oral DTX used as positive control. The oral bioavailability of DTX was increased to 68.9% for DTX-loaded nanoparticles compared to 6.5% for positive control. The nanoparticles showed stronger effect on the reduction of the transepithelial electrical resistance (TEER) of Caco-2 cell monolayer by opening the tight junctions. According to apparent permeability coefficient (Papp) results, the DTX-loaded NPs showed more specific permeation across the Caco-2 cell monolayer in comparison to the DTX. In conclusion, the nanoparticles prepared in this study showed promising results for the development of an oral drug delivery system for anticancer drugs. PMID:23971023

  9. Enhanced Oral Delivery of Docetaxel Using Thiolated Chitosan Nanoparticles: Preparation, In Vitro and In Vivo Studies

    Directory of Open Access Journals (Sweden)

    Shahrooz Saremi

    2013-01-01

    Full Text Available The aim of this study was to evaluate a nanoparticulate system with mucoadhesion properties composed of a core of polymethyl methacrylate surrounded by a shell of thiolated chitosan (Ch-GSH-pMMA for enhancing oral bioavailability of docetaxel (DTX, an anticancer drug. DTX-loaded nanoparticles were prepared by emulsion polymerization method using cerium ammonium nitrate as an initiator. Physicochemical properties of the nanoparticles such as particle size, size distribution, morphology, drug loading, and entrapment efficiency were characterized. The pharmacokinetic study was carried out in vivo using wistar rats. The half-life of DTX-loaded NPs was about 9 times longer than oral DTX used as positive control. The oral bioavailability of DTX was increased to 68.9% for DTX-loaded nanoparticles compared to 6.5% for positive control. The nanoparticles showed stronger effect on the reduction of the transepithelial electrical resistance (TEER of Caco-2 cell monolayer by opening the tight junctions. According to apparent permeability coefficient (Papp results, the DTX-loaded NPs showed more specific permeation across the Caco-2 cell monolayer in comparison to the DTX. In conclusion, the nanoparticles prepared in this study showed promising results for the development of an oral drug delivery system for anticancer drugs.

  10. Facile preparation of Ti{sup 3+} self-doped TiO{sub 2} nanosheets with dominant {0 0 1} facets using zinc powder as reductant

    Energy Technology Data Exchange (ETDEWEB)

    Si, Lingling; Huang, Ze’ai; Lv, Kangle, E-mail: lvkangle@mail.scuec.edu.cn; Tang, Dingguo; Yang, Changjun

    2014-07-15

    Highlights: • Ti{sup 3+}-doped high-energy TiO{sub 2} nanosheets was prepared using zinc powder as reductant. • Effects of Zn on morphology and BET surface areas of TiO{sub 2} nanosheets is negligible. • Zn powder resulted in the formation of Ti{sup 3+} self-doped anatase TiO{sub 2} nanosheets. • Ti{sup 3+} self-doped TiO{sub 2} nanosheets showed enhanced visible-light photoactivity. - Abstract: Ti{sup 3+} self-doped TiO{sub 2} nanosheets with dominant {0 0 1} facets for excellent visible-light photocatalytic activity were prepared by a facile one-pot hydrothermal reaction strategy using tetrabutyl titanate (TBT) as titanium source, hydrofluoric acid (HF) as structure-directing agent and zinc powder (Zn) as reductant. The synthesized catalysts were characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectra (XPS), diffuse reflectance spectrum (DRS) and nitrogen adsorption–desorption isotherms. The photocatalytic activity of the photocatalyst was evaluated by measure the formation rate of photo-induced hydroxyl radicals (·OH) under visible-light irradiation (λ = 420 ± 10 nm) using coumarin as a probe. It was found that the presence of zinc shows little effect on the morphology, phase structure, BET surface areas and pore structure. However, the addition of Zn powder resulted in the formation of Ti{sup 3+} self-doped anatase TiO{sub 2} nanosheets with dominant {0 0 1} facets, which is responsible for the enhanced visible-light photocatalytic activity. The sample prepared with zinc/TBT molar ratio of 0.3 showed the highest visible-light photocatalytic activity, which is 1.9 times higher than that of commercial P25 TiO{sub 2}.

  11. Preparing for Interaction : A comparative study on the different ways dutch actors prepare themself to work in the comprehensive approach

    NARCIS (Netherlands)

    Thönissen, F.H.; Homberg, M.J.C. van den; Pieneman, R.B.J.; Rjetjens, B.; Berg, P. van den

    2014-01-01

    This study provides an overview on how Dutch military and civilian professionals prepare themselves for a comprehensive approach in conflict-affected areas. What works for the different actors and what can be improved? The study addresses these and other questions.

  12. Reduction in Current Consumption of Small DC Motor with Rare-Earth Flexible Bonded Magnets Prepared by Powder Compacting Press and Hot Rolling

    Science.gov (United States)

    Yamashita, Fumitoshi; Watanabe, Akihiko; Fukunaga, Hirotoshi

    The usage of high-performance rare-earth magnets is one of the key technologies in the development of efficient small motors. Ring-shaped melt-spun Nd-Fe-B bonded magnets, prepared using a powder compacting press and/or injection molding, are generally used in typical applications to small efficient motors. For exploiting the maximum characteristics according to the variety of magnetic powder, however, the preparation method of the magnet, the magnet form, and the motor design needs to be changed for high-productivity as well as for improving total performance, including the magnetic properties of bonded magnets. This paper reports recent achievements in new preparation processes for rare-earth bonded magnets and small motors using new materials other than Nd-Fe-B melt-spun powder. This paper especially focuses on the method for maximally exploiting certain rare-earth magnetic powders . Furthermore, reduction in the current consumption of the small DC motor using the developed technique is reported.

  13. Dose reduction and optimization studies (ALARA) at nuclear power facilities. [PWR; BWR

    Energy Technology Data Exchange (ETDEWEB)

    Baum, J.W.; Meinhold, C.B.

    1983-01-01

    Brookhaven National Laboratory (BNL) has been commissioned by the Nuclear Regulatory Commission (NRC) to study dose-reduction techniques and effectiveness of as low as reasonably achievable (ALARA) planning at LWR plants. These studies have the following objectives: identify high-dose maintenance tasks; identify dose-reduction techniques; examine incentives for dose reduction; evaluate cost-effectiveness and optimization of dose-reduction techniques; and compile an ALARA handbook on data, engineering modifications, cost-effectiveness calculations, and other information of interest to ALARA practioners.

  14. NiO/YSZ Reduction for SOFC/SOEC Studied In Situ by Environmental Transmission Electron Microscopy

    DEFF Research Database (Denmark)

    Simonsen, Søren Bredmose; Agersted, Karsten; Hansen, Karin Vels;

    2014-01-01

    A typical anode for solid oxide fuel cells (SOFC) or cathode for solid oxide electrolysis cells (SOEC) is a complex porous structure of Ni and yttria-stabilized zirconia (YSZ). The porous Ni/YSZ is usually prepared from powder mixtures of NiO and YSZ, tape casted and sintered into a dense structure....... The study focusses on the temperature dependent dynamical morphology of the NiO/YSZ and on the possible influence of YSZ on the NiO reduction....... and finally reduced during start-up of the SOFC/SOEC in H2 at the operating temperature of the cell (ca. 800 °C). This contribution presents environmental transmission electron microscopy (ETEM) nanoscale observations of the reduction process of a NiO/YSZ powder in H2 at temperatures up to almost 1000 °C...

  15. In situ study of copper reduction in SrTi1-xCuxO3 nanoparticles.

    Science.gov (United States)

    Coletta, Vitor C; Marcos, Francielle C F; Nogueira, Francisco G E; Bernardi, Maria I B; Michalowicz, Alain; Gonçalves, Renato V; Assaf, Elisabete M; Mastelaro, Valmor R

    2016-01-21

    Perovskite strontium titanate is a promising functional material for gas sensors and catalysis applications. Herein, we report the preparation of SrTi1-xCuxO3 nanoparticles with Cu doped in the B sites using a modified polymeric precursor method. This study describes in detail the structural and local atomic configurations for the substitution of Cu into the titanium sites and its reducibility using X-ray diffraction (XRD), field emission gun scanning and transmission electron microscopies (FEG-SEM and TEM), X-ray absorption spectroscopy (XAS), X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction (TPR) analyses. Our results indicate that copper is segregated for x≥ 0.06. After exposing the samples to a hydrogen-rich atmosphere at temperatures over 500 K, copper is reduced from Cu(2+) to metallic Cu. This reduction was attributed to copper atoms that originated primarily from the CuO phase.

  16. Preparation of Chitosan Nanoparticles: A Study of Influencing Factors

    Science.gov (United States)

    Thakur, Anupama; Taranjit

    2011-12-01

    Chitosan (CS), a cationic polysaccharide, offers great advantages for ionic interactions with negatively charged species such as sodium tripolyphosphate (STPP) leading to the formation of biocompatible crosslinked chitosan nanoparticles In the present work, an attempt has been made to systematically study the following factors influencing the ionotropic gelation of chitosan with STPP to produce CS nanoparticles: effect of pH of solution, CS concentration, STPP concentration and CS/STPP ratio. The results show that with the increase in CS concentration, the yield of the nanoparticle decreases whereas size increases. The mean size of the prepared nanoparticles varied between 120 to 720 nm and zeta potential between +14 mV to +53 mV . Nanoparticle size and yield was found to be strongly dependent on solution pH. Nanoparticle size decreased with increase in solution pH from 4 to 5 and yield was found to be maximum at pH = 5. With increase in STPP concentration, the size and yield of the nanoparticle increased. The potential of CS nanoparticles to trap amoxicillin trihydrate, taken as the model drug, was also studied. The maximum drug loading capacity was found to be 35% at a solution pH = 5 for 0.2% CS and 0.086% STPP.

  17. Preparation of (/sup 11/C)buprenorphine - a potential radioligand for the study of the opiate receptor system in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Luthra, S.K.; Pike, V.W.; Brady, F.; Horlock, P.L.; Prenant, C.; Crouzel, C.

    1987-01-01

    A method is described for the preparation of (/sup 11/C)buprenorphine in high specific activity, based on the reaction of N-(de-cyclopropylmethyl)buprenorphine with ''no carrier added'' (1-/sup 11/C)cyclopropanecarbonyl chloride followed by reduction with lithium aluminium hydride. The (1-/sup 11/C)cyclopropanecarbonyl chloride is itself prepared from cyclotron-produced (/sup 11/C)carbon dioxide. The overall preparation time is 57 min from the end of radionuclide production, and the radiochemical yield is ca 20%, (decay-corrected from (/sup 11/C)-carbon dioxide). (/sup 11/C)Buprenophine has potential as a radio-ligand for the study of the opiate receptor system in vivo by means of position emission tomography.

  18. Similarity and Spacetime: Studies in Intertheoretic Reduction and Physical Significance

    Science.gov (United States)

    Fletcher, Samuel Craig

    This dissertation explores in particular a few ways in which similarity bears on general relativity, our best physical theory of space and time. The first way concerns the role of the concept of "physicality" in theorizing and using spacetime models, which manifests in at least two different ways. One is whether particular models are (or have properties that are) "physically unreasonable"---they are deemed to be pathological or otherwise artifactual, and so must excluded from the theory. Another is whether particular properties of those models are "physically significant"---warranted to be inferred about the properties of a physical system they represent. This distinction, which I draw in more detail in chapter 2, separates these two senses of physicality, the former modal-metaphysical and the latter inferential-epistemic. It is this latter that more intimately involves the notion of similarity, particular notions of which can be encoded through the use of topology. I argue then that there is no canonical topology on the models of general relativity. Rather, the choice of topology must be nontrivially dependent on the context of investigation. In chapter 3, I bring attention to another way in which similarity, as encoded in topology, can be put to substantive use, namely in better understanding the nature of the reductive relationship between general relativity and its predecessor, the Newtonian theory of space, time, and gravitation. In particular, I show how this relationship can be made both perfectly general---applying to any situation the theories describe---and explanatory of the Newtonian theory's success. Finally, in chapter 4, I explicate what I think are the deeper structural issues with certain examples due to Robert Geroch that are intended to show a certain topology commonly used in the physics literature in fact has several counterintuitive features. I show that there is in fact no topology that meets a strong version of Geroch's demands, but if those

  19. Study on test and preparation of load spectrum of hydraulic excavator

    Science.gov (United States)

    Zhang, Hong; Feng, Guodi; Zhang, Haijun; Wang, Xiaofeng; Zhang, Yingzhi

    2017-01-01

    Due to harsh working conditions, the components of hydraulic excavator are subject to large amount of alternating load and random load during the operation and they are seriously damaged. The test of load signal and preparation of load spectrum for the hydraulic excavator are studied in this paper. In the first place, pretreatment of filtering and noise reduction for load signal is conducted based on experimental test on site and experimental working condition analysis. After the load signal is processed in sections, distribution fitting is performed for information like mean amplitude after rain flow counting with the approach of probability statistics to get the probability distribution function for mean value and amplitude value. Finally the two dimensional load spectrum for mean amplitude is obtained and program spectrum loading solution of fatigue experiment is given. The study of load signal test and load spectrum preparation method for hydraulic excavator conducted in this paper is of great significance for clarification of load distribution of excavator and further reliability test of excavator.

  20. Studies on preparation of aceclofenac pellets by centrifugal granulator

    Directory of Open Access Journals (Sweden)

    Zibin GAO

    Full Text Available To prepare aceclofenac pellets by centrifugal granulation. Using 90~100 g of starch pellets as the core pellets,100 g of aceclofenac mixed with 50 g of microcrystalline cellulose(MCC and 4 g talc, methyl cellulose (HPMC as binder,the aceclofenac pellets were prepared by centrifugal granulation .And evaluate the quality of the pellets. The aceclofenac pellets had high yield and less losses,the pellets had a partical size of 0.70~0.88 mm(18~24 mesh)and had uniform particle size .the moisture ,drug content and dissolution meet the requirement . Aceclofenac pellets were prepared by the process of centrifugal granulation .The preparation prescription and process parameters were optimized by single factor method .and the pellets meet the standard requirements.

  1. Supported cobalt catalysts - preparation, characterization and reaction studies

    OpenAIRE

    Backman, Leif

    2009-01-01

    The aim of this work was to understand on the effect of thermal treatments, precursor and support on the interaction between the support and cobalt species, and further how the interaction affects the reducibility and dispersion of the catalyst. Silica and alumina supported cobalt catalysts were prepared, characterised and tested for catalytic activity. The catalysts were prepared by gas phase deposition techniques from cobalt acetylacetonate and cobalt carbonyl and by incipient wetness impre...

  2. Active MnO{sub x} electrocatalysts prepared by atomic layer deposition for oxygen evolution and oxygen reduction reactions

    Energy Technology Data Exchange (ETDEWEB)

    Pickrahn, Katie L.; Park, Sang Wook; Gorlin, Yelena; Lee, Han-Bo-Ram; Jaramillo, Thomas F.; Bent, Stacey F. [Department of Chemical Engineering, Stanford University, Stanford, CA 94305-5025 (United States)

    2012-10-15

    The ability to deposit conformal catalytic thin films enables opportunities to achieve complex nanostructured designs for catalysis. Atomic layer deposition (ALD) is capable of creating conformal thin films over complex substrates. Here, ALD-MnO{sub x} on glassy carbon is investigated as a catalyst for the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR), two reactions that are of growing interest due to their many applications in alternative energy technologies. The films are characterized by X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy, ellipsometry, and cyclic voltammetry. The as-deposited films consist of Mn(II)O, which is shown to be a poor catalyst for the ORR, but highly active for the OER. By controllably annealing the samples, Mn{sub 2}O{sub 3} catalysts with good activity for both the ORR and OER are synthesized. Hypotheses are presented to explain the large difference in the activity between the MnO and Mn{sub 2}O{sub 3} catalysts for the ORR, but similar activity for the OER, including the effects of surface oxidation under experimental conditions. These catalysts synthesized though ALD compare favorably to the best MnO{sub x} catalysts in the literature, demonstrating a viable way to produce highly active, conformal thin films from earth-abundant materials for the ORR and the OER. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Total Ownership Cost Reduction Case Study: AEGIS Radar Phase Shifters

    National Research Council Canada - National Science Library

    Bridger, Wray W; Ruiz, Mark D

    2006-01-01

    The goal of this research is to provide a case study that captures the production and design processes and program management solutions used to reduce total ownership costs of AEGIS Radar Phase Shifters...

  4. Photocatalytic reduction of CO2 over Ag/TiO2 nanocomposites prepared with a simple and rapid silver mirror method

    Science.gov (United States)

    Yu, Bingcheng; Zhou, Yong; Li, Peng; Tu, Wenguang; Li, Ping; Tang, Lanqin; Ye, Jinhua; Zou, Zhigang

    2016-06-01

    The photocatalytic reduction of CO2 over Ag/TiO2 composites prepared with a simple silver mirror reaction method was investigated under UV-visible irradiation in both gas-phase (CO2 + water vapor) and aqueous solution (CO2-saturated NaHCO3 solution) systems. The as-prepared Ag/TiO2 nanocomposite exhibits efficient photocatalytic activity due to the surface plasmonic resonance and electron sink effect of the Ag component, which was found to be closely related to the size and loading amount of Ag. The rapid silver method is effective at curbing the size of Ag, so photocatalytic activity can be improved. Diverse organic chemical products were detected, including mainly methane and methanol as well as a small amount of C2 and C3 species such as acetaldehyde and acetone. Possible photocatalytic mechanisms were proposed. This artificial photosynthesis process may give a prosperous route to the removal of CO2 while simultaneously converting CO2 to valuable fuels based on highly efficient photocatalysts.The photocatalytic reduction of CO2 over Ag/TiO2 composites prepared with a simple silver mirror reaction method was investigated under UV-visible irradiation in both gas-phase (CO2 + water vapor) and aqueous solution (CO2-saturated NaHCO3 solution) systems. The as-prepared Ag/TiO2 nanocomposite exhibits efficient photocatalytic activity due to the surface plasmonic resonance and electron sink effect of the Ag component, which was found to be closely related to the size and loading amount of Ag. The rapid silver method is effective at curbing the size of Ag, so photocatalytic activity can be improved. Diverse organic chemical products were detected, including mainly methane and methanol as well as a small amount of C2 and C3 species such as acetaldehyde and acetone. Possible photocatalytic mechanisms were proposed. This artificial photosynthesis process may give a prosperous route to the removal of CO2 while simultaneously converting CO2 to valuable fuels based on highly

  5. A Case Study of the Reduction of Aberrant, Repetitive Responses of an Adolescent with Autism.

    Science.gov (United States)

    Gunter, Philip L.; And Others

    1993-01-01

    In this case study, music was applied noncontingently and contingently across four settings with an adolescent male with autism, to reduce aberrant, repetitive vocalizations. The intervention was associated with dramatic reductions in the primary aberrant behavior and reductions in two other aberrant behaviors. Task performance was differentially…

  6. Comparison of image quality in head CT studies with different dose-reduction strategies

    DEFF Research Database (Denmark)

    Johansen, Jeppe; Nielsen, Rikke; Fink-Jensen, Vibeke

    -reduction maneuvers is reduction of image quality due to image noise or artifacts. The aim of our study was therefore to find the best diagnostic images with lowest possible dose. We present results of dose- and image quality optimizing strategies of brain CT examinations at our institution. We compare sequential...

  7. Enhanced formic acid electro-oxidation on PdIr nanoparticles prepared by ethylene glycol-assisted NaBH4 reduction process.

    Science.gov (United States)

    Chen, Jinwei; Wang, Gang; Wang, Xueqin; Tian, Jing; Zhu, Shifu; Wang, Ruilin

    2013-10-01

    The carbon supported PdIr nanoparticles were synthesized by an ethylene glycol-assisted NaBH4 reduction method, and the mass ratio of Pd to Ir was optimized. Then, their performances for formic acid electro-oxidation (FAEO) were investigated. The XRD and TEM characterizations show that the prepared PdIr/C catalysts have small mean size and good dispersion of PdIr nanoparticles. The electrochemical measurements demonstrate that the PdIr/C catalysts have greatly enhanced performance for FAEO compared with the Pd/C catalyst. The PdIr/C catalysts show higher current density and more than 50 mV negative shift of onset and peak potential than that of the Pd/C catalyst. With the optimal mass ratio of Pd to Ir, the PdIr/C-5 catalyst presents the highest catalytic activity for FAEO.

  8. Response Behaviour of a Hydrogen Sensor Based on IonicConducting Polymer-metal Interfaces Prepared by the ChemicalReduction Method

    Directory of Open Access Journals (Sweden)

    Werner Weppner

    2006-04-01

    Full Text Available A solid-state amperometric hydrogen sensor based on a protonated Nafionmembrane and catalytic active electrode operating at room temperature was fabricated andtested. Ionic conducting polymer-metal electrode interfaces were prepared chemically byusing the impregnation-reduction method. The polymer membrane was impregnated withtetra-ammine platinum chloride hydrate and the metal ions were subsequently reduced byusing either sodium tetrahydroborate or potassium tetrahydroborate. The hydrogen sensingcharacteristics with air as reference gas is reported. The sensors were capable of detectinghydrogen concentrations from 10 ppm to 10% in nitrogen. The response time was in therange of 10-30 s and a stable linear current output was observed. The thin Pt films werecharacterized by XRD, Infrared Spectroscopy, Optical Microscopy, Atomic ForceMicroscopy, Scanning Electron Microscopy and EDAX.

  9. Enhanced photovoltaic performance of a dye-sensitized solar cell using graphene-TiO2 photoanode prepared by a novel in situ simultaneous reduction-hydrolysis technique.

    Science.gov (United States)

    Chen, Liang; Zhou, Yong; Tu, Wenguang; Li, Zhengdao; Bao, Chunxiong; Dai, Hui; Yu, Tao; Liu, Jianguo; Zou, Zhigang

    2013-04-21

    Enhanced photovoltaic performance of a DSSC using graphene-TiO2 photoelectrodes prepared by our recent in situ simultaneous reduction-hydrolysis technique (Adv. Funct. Mater., 2012, DOI: 10.1002/adfm.201202349, in press) was achieved. The DSSCs based on the G-TiO2 nanocomposites improved their overall energy conversion efficiency to 7.1%. The results prove that the promoting effect of graphene is strongly dependent on its content; namely, the efficiency of DSSCs increases and then decreases with increasing graphene content in TiO2-graphene composites. Excessive graphene in the nanocomposite leads to a decrease of the light harvest of dye molecules and thus a negative effect on the power conversion efficiency of DSSCs.

  10. Controlled release metformin hydrochloride microspheres of ethyl cellulose prepared by different methods and study on the polymer affected parameters.

    Science.gov (United States)

    Choudhury, Pratim K; Kar, Mousumi

    2009-02-01

    The objectives of this investigation were to prepare microspheres of the anti-diabetic drug, metformin hydrochloride, using ethyl cellulose as the polymer and evaluate the encapsulation efficiency and release characteristics in vitro and in vivo; utilizing different microencapsulation techniques. Different proportions of polymer were used to obtain varying drug-polymer ratios. Physical properties, loading efficiency and dissolution rate were dependent on the method chosen for preparation and also on the drug-to-polymer ratio. The addition of surfactant during emulsification and petroleum ether in non-solvent addition process affected release of drug and also size distribution of microspheres. To investigate the type of mechanism that occurs, dissolution data were plotted according to different kinetic models. In vitro release studies show first order and Higuchi model release characteristics being exhibited. All the results were treated statistically to validate the findings. Significant differences in percentage yield, entrapment efficiency and sustaining capacity were seen with microspheres prepared by two different methods. In vivo studies in normal and hyperglycemic mice show faster glucose reduction with microspheres prepared by the evaporation method, whereas the release sustaining effect was more pronounced with microspheres prepared by the non-solvent addition method.

  11. Studies on the reduction of radon plate-out

    Energy Technology Data Exchange (ETDEWEB)

    Bruemmer, M.; Nakib, M.; Calkins, R.; Cooley, J., E-mail: cooley@physics.smu.edu; Sekula, S. [Department of Physics, Southern Methodist University, Dallas, TX 75275 (United States)

    2015-08-17

    The decay of common radioactive gases, such as radon, produces stable isotopes by a sequence of daughter particles with varied half-lives. These daughter particles are a significant source of gamma, neutron, and alpha (α) particle backgrounds that can mimic desired signals in dark matter and neutrinoless double beta decay experiments. In the LUMINA Laboratory at Southern Methodist University (SMU), studies of radon plate-out onto copper samples are conducted using one of XIA’s first five UltraLo 1800 alpha counters. We present results from investigations into various mitigation approaches. A custom-built copper holder (in either plastic or metal) has been designed and produced to maximize the copper’s exposure to {sup 220}Rn. The {sup 220}Rn source is a collection of camping lantern mantles. We present the current status of control and experimental methods for addressing radon exposure levels.

  12. Studies on the Reduction of Radon Plate-Out

    CERN Document Server

    Bruemmer, M; Calkins, R; Cooley, J; Sekula, S

    2015-01-01

    The decay of common radioactive gases, such as radon, produces stable isotopes by a sequence of daughter particles with varied half-lives. These daughter particles are a significant source of gamma, neutron, and alpha particle backgrounds that can mimic desired signals in dark matter and neutrinoless double beta decay experiments. In the LUMINA Laboratory at Southern Methodist University (SMU), studies of radon plate-out onto copper samples are conducted using one of XIA's first five UltraLo 1800 alpha counters. We present results from investigations into various mitigation approaches. A custom-built copper holder (in either plastic or metal) has been designed and produced to maximize the copper's exposure to 220Rn. The 220Rn source is a collection of camping lantern mantles. We present the current status of control and experimental methods for addressing radon exposure levels.

  13. A comparative study of two stochastic mode reduction methods

    Energy Technology Data Exchange (ETDEWEB)

    Stinis, Panagiotis

    2005-09-01

    We present a comparative study of two methods for thereduction of the dimensionality of a system of ordinary differentialequations that exhibits time-scale separation. Both methods lead to areduced system of stochastic differential equations. The novel feature ofthese methods is that they allow the use, in the reduced system, ofhigher order terms in the resolved variables. The first method, proposedby Majda, Timofeyev and Vanden-Eijnden, is based on an asymptoticstrategy developed by Kurtz. The second method is a short-memoryapproximation of the Mori-Zwanzig projection formalism of irreversiblestatistical mechanics, as proposed by Chorin, Hald and Kupferman. Wepresent conditions under which the reduced models arising from the twomethods should have similar predictive ability. We apply the two methodsto test cases that satisfy these conditions. The form of the reducedmodels and the numerical simulations show that the two methods havesimilar predictive ability as expected.

  14. Reduction of persistent organic pollutants in fishmeal: a feasibility study.

    Science.gov (United States)

    Oterhals, Age; Nygård, Einar

    2008-03-26

    The dioxin, dioxin-like polychlorinated biphenyl (DL-PCB), fat, and dry matter partitioning during fishmeal production have been studied in pilot scale. Most of the dry matter and lipid content in the fishmeal could be ascribed to the press cake intermediate product. Dioxins and DL-PCBs are fat-soluble compounds, and the process partitioning is reflected by the fat partitioning data. Enzyme and heat treatment of the press cake and stickwater concentrate did not improve fat separation. Soybean oil extraction of the press cake reduced the dioxin and DL-PCB content by 97%. Less exchange of fatty acids was observed (56-72%). Combined with fat separation of the stickwater concentrate, the applied process conditions were able to give a fishmeal decontamination rate higher than hexane and isopropanol extraction of the fishmeal. Quantification of fat content based on chloroform/methanol extraction was found to be the best protocol to estimate fat partitioning and decontamination effects. The oil extraction process requires further optimization, but has several advantages compared to organic solvent extraction. These include easy implementation in an existing fishmeal processing line, use of a safe and nonflammable extraction medium, and expected lower investment and operation costs. A new integrated fishmeal and fish oil production and decontamination process line is proposed.

  15. Study on denitration technology of coal char reduction method

    Directory of Open Access Journals (Sweden)

    Wenjie FU

    2016-06-01

    Full Text Available In order to more effectively control NO emissions in coal-fired flue gas, the denitration reaction is carried out with simulated industrial boiler flue gas in a fixed bed reactor. The influence of char types, reaction conditions, the composition of flue gas and other factors on the conversion rate of NO are discussed. The result shows that the industrial semi-coke is the most suitable experimental coal in the three coals studied, and the industrial semi-coke particle size of 0.6 ~ 10 mm is relatively suitable; The conversion rate of NO increases gradually with the increase of temperature, and when the reaction temperature is 700 ℃ and the space velocity is 10 000 h-1, the conversion rate of NO can reach 99%; the conversion rate of NO decreases gradually as airspeed increases, but the airspeed change has no effect on the conversion rate of NO at 700 ℃; under anaerobic conditions,the change of NO concentration has no effect on the conversion rate of NO; at the same temperature, NO conversion rate is higher at the presence of oxygen compared with that at anaerobic situation, and the conversion rate of NO is the highest when O2 concentration is 4%; under aerobic conditions, the concentration change of SO2 and CO2 has no effect on the conversion rate of NO.

  16. Selective catalytic reduction of NO with NH3 over CeO2-ZrO2-WO3 catalysts prepared by different methods

    Science.gov (United States)

    Ning, Ping; Song, Zhongxian; Li, Hao; Zhang, Qiulin; Liu, Xin; Zhang, Jinhui; Tang, Xiaosu; Huang, Zhenzhen

    2015-03-01

    The selective catalytic reduction (SCR) of NO by NH3 has been investigated over the CeO2-ZrO2-WO3 (CZW) catalysts prepared by hydrothermal synthesis, incipient impregnation, co-precipitation and sol-gel methods. The results indicate that the CZW catalyst prepared by hydrothermal method shows the best SCR activity, and more than 90% NO conversion is obtained at 195-450 °C with a gas hourly space velocity of 50,000 h-1. The samples are characterized by XRD, N2 adsorption-desorption, SEM, EDS, XPS, H2-TPR, NH3-TPD and Pyridine-IR techniques. The results imply that the superior SCR activity of CZW catalyst is contributed to the excellent redox property, strong acidity and highest content of chemisorbed oxygen species. Furthermore, the larger surface area and greater total pore volume improve the redox ability and enhance NO conversion at low temperature, while the co-existence of Lewis and Brønsted acid sites enhance the SCR activity at high temperature.

  17. Preparation and characterizations of highly dispersed carbon supported PdxPty/C catalysts by a modified citrate reduction method for formic acid electrooxidation

    Science.gov (United States)

    Li, Zuopeng; Li, Muwu; Han, Mingjia; Zeng, Jianhuang; Li, Yuexia; Guo, Yanqin; Liao, Shijun

    2014-05-01

    Carbon supported PdxPty/C (atomic ratio x:y from 1:1 to 6:1) have been prepared by a modified citrate reduction method assisted by inorganic stabilizers. Without using high molecular capping agents as stabilizers, the PdxPty/C catalysts are highly dispersed on the carbon support and no particle aggregations are found for the PdxPty/C catalysts. X-ray photoelectron spectroscopy reveals either Pt or Pd segregation for the PdxPty/C catalysts depending on Pd/Pt atomic ratio. CO stripping in 0.5 M H2SO4 and repeated formic acid oxidation cyclic voltammetry in 0.5 M HCHO + 0.5 M H2SO4 have been conducted to test out the CO tolerance and stability of the catalysts, respectively. It has been found that, with the increase of Pd/Pt atomic ratio, the CO stripping peak potential increases (less CO tolerant), whereas the catalyst stability towards formic acid oxidation decreases. The as-prepared catalysts reveal excellent mass-normalized formic acid oxidation activity as compared with published results possibly due to high dispersion and the absence of high molecular capping agents.

  18. Meal Replacement Mass Reduction and Integration Acceptability Study

    Science.gov (United States)

    Sirmons, T.; Barrett, A.; Richardson, M.; Arias, D.; Schneiderman, J.; Slack, K.; Williams, T.; Douglas, G.

    2017-01-01

    NASA, in planning for long-duration missions, has an imperative to provide a food system with the necessary nutrition, acceptability, and safety to ensure sustainment of crew health and performance. The Orion Multi-Purpose Crew Vehicle (MPCV) and future exploration missions are mass constrained; therefore the team is challenged to reduce the mass of the food system by 10% while maintaining product safety, nutrition, and acceptability. Commercially available products do not meet the nutritional requirements for a full meal replacement in the spaceflight food system, and it is currently unknown if daily meal replacements will impact crew food intake and psychosocial health over time. The purpose of this study was to develop a variety of nutritionally balanced breakfast replacement bars that meet spaceflight nutritional, microbiological, sensorial, and shelf-life requirements, while enabling a 10% savings in food mass. To date, six nutrient-dense meal replacement bars (approximately 700 calories per bar) have been developed, using traditional methods of compression as well as novel ultrasonic compression technologies developed by Creative Resonance Inc. (Phoenix, AZ). The four highest rated bars were evaluated in the Human Exploration Research Analog (HERA) to assess the frequency with which actual meal replacement options may be implemented. Specifically, overall impact of bars on mood, satiety, digestive discomfort, and satisfaction with food. These factors are currently being analyzed to inform successful implementation strategies where crew maintain adequate food intake. In addition, these bars are currently undergoing shelf-life testing to determine long-term sensory acceptability, nutritional stability, qualitative stability of analytical measurements (i.e. water activity and texture), and microbiological compliance over two years of storage at room temperature and potential temperature abuse conditions to predict long-term acceptability. It is expected that

  19. Pulsed ELDOR spectroscopy of the Mo(V)/Fe(III) state of sulfite oxidase prepared by one-electron reduction with Ti(III) citrate.

    Science.gov (United States)

    Codd, Rachel; Astashkin, Andrei V; Pacheco, Andrew; Raitsimring, Arnold M; Enemark, John H

    2002-03-01

    The titration of chicken liver sulfite oxidase (SO) with the one-electron reductant Ti(III) citrate, at pH 7.0, results in nearly quantitative selective reduction of the Mo(VI) center to Mo(V), while the b-type heme center remains in the fully oxidized Fe(III) state. The selective reduction of the Mo(VI/V) couple has been established from electronic and EPR spectra. The electronic spectrum of the Fe(III) heme center is essentially unchanged during the titration, and the continuous wave (CW)-EPR spectrum shows the appearance of the well-known Mo(V) signal due to the low pH ( lpH) form of SO. Further confirmation of the selective formation of the Mo(V)/Fe(III) form of SO is provided by the approximately 1:1 ratio of the integrated intensities of the Mo(V) and low-spin Fe(III) EPR signals after addition of one equivalent of Ti(III). The selective generation of the Mo(V)/Fe(III) form of SO is unexpected, considering that previous microcoulometry and flash photolysis investigations have indicated that the Mo(VI/V) and Fe(III/II) couples of SO have similar reduction potentials at pH 7. The nearly quantitative preparation of the one-electron reduced Mo(V)/Fe(III) form of SO by reduction with Ti(III) has enabled the interaction between these two paramagnetic metal centers, which are linked by a flexible loop with no secondary structure, to be investigated for the first time by variable-frequency pulsed electron-electron double resonance (ELDOR) spectroscopy. The ELDOR kinetics were obtained from frozen solutions at 4.2 K at several microwave frequencies by pumping on the narrow Mo(V) signal and observing the effect on the Fe(III) primary echo at both higher and lower frequencies within the microwave C-band region. The ELDOR data indicate that freezing the solution of one-electron reduced SO produces localized regions where the concentration of SO approaches that in the crystal structure, which results in the interpair interactions being the dominant dipolar interaction

  20. 碳热还原法制备碳化钒钛固溶粉体%Preparation of Vanadium Titanium Carbide Solid Solution Powders by Carbon Thermal Reduction

    Institute of Scientific and Technical Information of China (English)

    任杰; 陈敏; 方民宪; 王淅茹

    2016-01-01

    以偏钒酸铵、石墨和二氧化钛为原料通过碳热还原法制备了单相碳化钒钛固溶粉体。结合DSC、XRD、SEM分析方法研究了碳化钒钛粉体制备过程中低温一次还原与高温二次还原的物相组成,优化了配碳系数。结果表明,和偏钒酸铵直接碳热还原及二氧化钛直接碳热还原相比,偏钒酸铵和二氧化钛混合粉料碳热还原反应物之间的接触面积增加,有利于还原反应的进行。当配碳系数为0.8时经高温二次还原形成结晶较好的单相碳化钒钛固溶体。%Single phase TiVC2 was prepared by carbothermal reduction of metavanadate, graphite and titanium dioxide mixed raw materials. Phase composition and optimized carbon coefifcient were investigated by combination of XRD and SEM analysis. Results showed that single phase TiVC2 with good crystallinity was obtained after second reduction when the carbon coefifcient was 0.80.

  1. Stable dispersion of graphene solution prepared by hydrothermai reduction%高压釜热还原制备稳定分散的石墨烯溶液

    Institute of Scientific and Technical Information of China (English)

    冉启燕; 张海燕; 陈易明; 叶剑; 李春辉

    2012-01-01

    A improved Hummers method was employed to prepare graphite oxide using natural flake graphite as raw materials. The graphene oxide solution was prepared by ultrasonic dispersion, and the pH value of solution was changed through adding different volume fraction of hydrazine hydrate. After hydrothermal reduction in au- toclave, stable dispersion graphene solutions were obtained. The as prepared samples were characterized by X- ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, atomic force microscope, zeta potential and optical microscope. The influence of temperature and pH value of the sta- bility of graphene solutions was investigated.%以天然鳞片石墨为原料,用改进的Hummers法制备氧化石墨。超声分散制备氧化石墨烯溶液,通过加入不同量的水合肼调节溶液的pH值,再通过水热法热还原,制备了在水中稳定分散的石墨烯溶液。利用扫描电子显微镜(SEM)、高分辨透射电镜(HR-TEM)、拉曼光谱(Raman)、原子力显微镜(AFM)、X射线衍射分析(XRD)、zeta电位及光学显微镜对制备的样品进行了表征,研究了不同温度、pH值对石墨烯溶液稳定性的影响。

  2. Preparation of DNA films for studies under vacuum conditions

    DEFF Research Database (Denmark)

    Smialek, M. A.; Balog, Richard; Jones, N. C.;

    2010-01-01

    Experiments were carried out to determine the optimum conditions required for the preparation of uniform films of supercoiled plasmid DNA to be used in irradiation experiments under high vacuum conditions. Investigations reveal that significant damage to the DNA molecules occurs due to the evacua...

  3. Small College Teacher Preparation Program Evaluations: A Multiple Case Study

    Science.gov (United States)

    Saynes, Kathryn

    2013-01-01

    The methods of evaluating teacher preparation programs are becoming increasingly more reliant on student test data. These test data driven formats, however, are not appropriate for small colleges. Small colleges are currently left off the Tennessee Report Card on the Effectiveness of Teacher Training Programs because the colleges did not produce…

  4. Fe(II)–Al(III) layered double hydroxides prepared by ultrasound-assisted co-precipitation method for the reduction of bromate

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Yu [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China); Yang, Qi, E-mail: yangqi@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China); Luo, Kun; Wu, Xiuqiong [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China); Li, Xiaoming, E-mail: xmli@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China); Liu, Yang [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Urban and Rural Garbage Disposal Technology Research Center, Hunan Province, Changsha 410082 (China); Tang, Wangwang; Zeng, Guangming; Peng, Bo [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China)

    2013-04-15

    Highlights: ► Fe(II)–Al(III) LDHs were synthesized by ultrasound-assisted co-precipitation method. ► The Fe–Al (30 min) exhibited highly reduction reactivity on bromate. ► Pseudo-first-order model described the experimental data well. ► The mechanisms of bromate removal were proposed. -- Abstract: Bromate is recognized as an oxyhalide disinfection byproduct in drinking water. In this paper, Fe(II)–Al(III) layered double hydroxides (Fe–Al LDHs) prepared by the ultrasound-assisted co-precipitation method were used for the reduction of bromate in solution. The Fe–Al LDHs particles were characterized by X-ray diffractometer, scanning electron microscopy and thermogravimetry–differential scanning calorimetry. It was found that ultrasound irradiation assistance promoted the formation of the hydrotalcite-like phase and then improved the removal efficiency of bromate. In addition, the effects of solid-to-solution ratio, contact time, initial bromate concentration, initial pH, coexisting anions on the bromate removal were investigated. The results showed the bromate with an initial concentration of 1.56 μmol/L could be completely removed from solution by Fe–Al LDHs within 120 min. When the initial bromate concentration was 7.81 μmol/L, the Fe–Al LDHs with irradiation time of 30 min exhibited the optimum removal efficiency and the bromate removal capacity (q{sub e}) was 6.80 μmol/g. In addition, the appearance of sulfate and production of bromide were observed simultaneously in this process, which suggested that ion-exchange between sulfate and bromate, and the reduction of bromate to bromide by Fe{sup 2+} were the main mechanisms responsible for the bromate removal by Fe–Al LDHs.

  5. Home versus Office blood pressure MEasurements : Reduction of Unnecessary treatment Study: Rationale and Study design of the HOMERUS Trial

    NARCIS (Netherlands)

    Verberk, WJ; Kroon, AA; Kessels, AGH; Dirksen, C; Nelemans, PJ; Lenders, JWM; Thien, TABM; van Montfrans, GA; Smit, AJ; de Leeuw, PW

    2003-01-01

    The Home versus Office MEasurements, Reduction of Unnecessary treatment Study (HOMERUS) is a multicentre prospective study, primarily designed to examine in subjects with mild to moderate hypertension whether treatment decisions based on home blood pressure measurements can lead to reduction in the

  6. Ordered mesoporous materials as model supports to study catalyst preparation

    NARCIS (Netherlands)

    Sietsma, J.R.A.

    2007-01-01

    Catalysts are indispensable to modern-day society because of their prominent role in petroleum refining, chemical processing, and the reduction of environmental pollution. The catalytically active component often consists of small metal (oxide) particles that are supported on a carrier such as silic

  7. Facile preparation of carbon coated magnetic Fe{sub 3}O{sub 4} particles by a combined reduction/CVD process

    Energy Technology Data Exchange (ETDEWEB)

    Tristao, Juliana C.; Oliveira, Aline A.S. [Departamento de Quimica, Universidade Federal de Minas Gerais, Belo Horizonte-MG, 31270-901 (Brazil); Ardisson, Jose D. [Laboratorio de Fisica Aplicada, CDTN, Belo Horizonte, MG 30123-970 (Brazil); Dias, Anderson [Departamento de Quimica, Universidade Federal de Ouro Preto, Ouro Preto-MG, 35400-000 (Brazil); Lago, Rochel M., E-mail: rochel@ufmg.br [Departamento de Quimica, Universidade Federal de Minas Gerais, Belo Horizonte-MG, 31270-901 (Brazil)

    2011-05-15

    Graphical abstract: Magnetic carbon coated Fe{sub 3}O{sub 4} particles are prepared by a one step combined reduction of Fe{sub 2}O{sub 3} together with a CVD process of using methane. Analyses show that the Fe{sub 2}O{sub 3} is reduced by methane to produce mainly Fe{sub 3}O{sub 4} particles coated with amorphous carbon. These materials can be separated into two fractions by simple dispersion in water and can be used as adsorbents, catalyst supports and rapid coagulation systems. Research highlights: {yields} Magnetic Fe{sub 3}O{sub 4} particles coated with a very thin layer of amorphous carbon (4 wt%). {yields} Combined reduction of Fe{sub 2}O{sub 3} with a Chemical Vapor Deposition process using methane. {yields} Nanoparticles with an average size of 100-200 nm. {yields} Uses as adsorbent, catalyst support and rapid coagulation systems. -- Abstract: In this work, we report a simple method for the preparation of magnetic carbon coated Fe{sub 3}O{sub 4} particles by a single step combined reduction of Fe{sub 2}O{sub 3} together with a Chemical Vapor Deposition process using methane. The temperature programmed reaction monitored by Moessbauer, X-ray Diffraction and Raman analyses showed that Fe{sub 2}O{sub 3} is directly reduced by methane at temperatures between 600 and 900 {sup o}C to produce mainly Fe{sub 3}O{sub 4} particles coated with up to 4 wt% of amorphous carbon. These magnetic materials can be separated into two fractions by simple dispersion in water, i.e., a settled material composed of large magnetic particles and a suspended material composed of nanoparticles with an average size of 100-200 nm as revealed by Scanning Electron Microscopy and High-resolution Transmission Electron Microscopy. Different uses for these materials, e.g., adsorbents, catalyst supports, rapid coagulation systems, are proposed.

  8. 75 FR 17132 - Intent To Prepare a Draft Environmental Impact Statement for Hurricane and Storm Damage Reduction...

    Science.gov (United States)

    2010-04-05

    ... cooperation with St. Johns County, the study will evaluate alternatives that will maximize HSDR while... Secretary of the Army broad authorization to survey coastal areas of the United States and its possessions... nourishment along St. Augustine Beach. Initial fill was completed in January 2003. Authority for the...

  9. Finite element model reduction application to parametric studies and optimization of rotorcraft structures

    Science.gov (United States)

    Hashemi-Kia, M.; Toossi, M.

    1990-01-01

    As a result of this work, a reduction procedure has been developed which can be applied to large finite element model of airframe type structures. This procedure, which is tailored to be used with MSC/NASTRAN finite element code, is applied to the full airframe dynamic finite element model of AH-64A Attack Helicopter. The applicability of the resulting reduced model to parametric and optimization studies is examined. Through application of the design sensitivity analysis, the viability and efficiency of this reduction technique has been demonstrated in a vibration reduction study.

  10. Comparative Studies of Clustering Techniques for Real-Time Dynamic Model Reduction

    CERN Document Server

    Hogan, Emilie; Halappanavar, Mahantesh; Huang, Zhenyu; Lin, Guang; Lu, Shuai; Wang, Shaobu

    2015-01-01

    Dynamic model reduction in power systems is necessary for improving computational efficiency. Traditional model reduction using linearized models or offline analysis would not be adequate to capture power system dynamic behaviors, especially the new mix of intermittent generation and intelligent consumption makes the power system more dynamic and non-linear. Real-time dynamic model reduction emerges as an important need. This paper explores the use of clustering techniques to analyze real-time phasor measurements to determine generator groups and representative generators for dynamic model reduction. Two clustering techniques -- graph clustering and evolutionary clustering -- are studied in this paper. Various implementations of these techniques are compared and also compared with a previously developed Singular Value Decomposition (SVD)-based dynamic model reduction approach. Various methods exhibit different levels of accuracy when comparing the reduced model simulation against the original model. But some ...

  11. Preparation of High Purity Manganese Carbonate from the Reduction of Pyrolusite Using Cane Juice as the Reductant%甘蔗汁还原软锰矿制备高纯碳酸锰工艺研究

    Institute of Scientific and Technical Information of China (English)

    蔡振勇; 易清风; 宋伟

    2011-01-01

    采用甘蔗汁作为还原剂,在稀硫酸介质中湿法还原软锰矿制备高纯碳酸锰.当甘蔗汁与软锰矿质量比为1.15时,锰的浸出率在95%以上.用活性炭对硫酸锰滤液进行吸附处理,通过单因素实验确定最佳脱色工艺参数,结果表明:当活性炭与甘蔗汁质量比为0.1,溶液pH值为2,反应时间3h时,硫酸锰粗滤液的脱色率在94%以上;然后加入硫化钡除去溶液的重金属离子,过滤,向滤液中加入二氟化锰使溶液中的钙、镁等离子沉淀除去得高纯硫酸锰溶液,将碳酸氢铵加入硫酸锰溶液中制备出高纯碳酸锰.经检测产品纯度在95%以上.%In this paper, manganese carbonate was prepared by the reduction of pyrolusite with cane juice as a reductant in dilute sulfuric acid solution. When the mass ratio of cane juice to pyrolusite is 1.15, the leaching rate of manganese can reach more than 95%. Manganese sulfate solution was treated by using activated carbon in order to remove the impurities. Optimal parameters affecting the decolorization efficiency were determined by the single factor method. The results show that the decolorzation rate can reach more than 94% under the condition of activated carbon to cane juice quality mass ratio of 0.1 ,pH 2,and reaction time of 3 h. Heavy metal ions were removed by adding barium sulfide to the solution. After being filtrated,manganese difluoride was added to the filtrate to precipitate Ca2+ ,Mg2+ and other impurities, and high purity manganese sulfate solution was then obtained. High purity manganese carbonate was prepared by adding ammonium bicarbonate to the pure manganese sulfate solution. Manganese carbonate purity can reach more than 95% .

  12. A comparative study of electrochemical reduction of isatin and its synthesized Schiff bases at HMDE

    Indian Academy of Sciences (India)

    Alpana K Gupta; Rajendra S Sindal

    2009-05-01

    The electrochemical behaviour of a series of Schiff base i.e. 3-[5-phenylpyrazol-3-ylimino]indol-2-ones (IIa-e) synthesized by the reaction of various 5-substituted isatins with 3-amino-5-phenyl-pyrazole has been investigated and compared with corresponding isatin in dimethylformamide in 0.1 M LiCl using cyclic voltammetry at Hanging Mercury Drop Electrode. All synthesized Schiff bases exhibit a single irreversible two-electron reduction wave in contrast with the two discrete one-electron transfer reduction waves observed for isatin in this medium. Observation of a well-developed single reduction wave can be attributed to the higher basicity of the nitrogen species of the imine bond of Schiff bases, making proton abstraction as well as second electron transfer both rapid. The compounds are subjected to constant potential preparative electrolysis. The products are identified as secondary amines by spectroscopic methods. A mechanism for the electro-reduction process has been proposed. Kinetic parameters have also been calculated.

  13. Nata de coco (NDC) hydrogel as nanoreactors for preparation iron nanoparticles (FeNps) from ferrocenium reduction

    Energy Technology Data Exchange (ETDEWEB)

    Andarini, Mellissa; Lazim, Azwan [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor (Malaysia)

    2014-09-03

    This study focuses on hydrogel as nano template to produce iron nanoparticles (FeNps). Radical polymerization was used to synthesize the hydrogel from nata de coco (NDC-g-PAA). Ferrocenium (FcCL) with 1 × 10{sup −4} g/ml has successfully incorporated with NDC-g-PAA hydrogel system and reduce using sodium hydroxide (NaOH) at different concentrations. Transmission electron microscopy (TEM) result demonstrates that the size of FeNps produced was about 5 – 20 nm. Morphological analysis of hydrogel is carried out by scanning electron microscopy (SEM), SEM-EDEX is used to determine percentage of iron (Fe) in hydrogel. The results offer a wide range of application in various areas, especially the use of hydrogel system as a responsive template.

  14. [Optimized sample preparation for metabolome studies on Streptomyces coelicolor].

    Science.gov (United States)

    Li, Yihong; Li, Shanshan; Ai, Guomin; Wang, Weishan; Zhang, Buchang; Yang, Keqian

    2014-04-01

    Streptomycetes produce many antibiotics and are important model microorgansims for scientific research and antibiotic production. Metabolomics is an emerging technological platform to analyze low molecular weight metabolites in a given organism qualitatively and quantitatively. Compared to other Omics platform, metabolomics has greater advantage in monitoring metabolic flux distribution and thus identifying key metabolites related to target metabolic pathway. The present work aims at establishing a rapid, accurate sample preparation protocol for metabolomics analysis in streptomycetes. In the present work, several sample preparation steps, including cell quenching time, cell separation method, conditions for metabolite extraction and metabolite derivatization were optimized. Then, the metabolic profiles of Streptomyces coelicolor during different growth stages were analyzed by GC-MS. The optimal sample preparation conditions were as follows: time of low-temperature quenching 4 min, cell separation by fast filtration, time of freeze-thaw 45 s/3 min and the conditions of metabolite derivatization at 40 degrees C for 90 min. By using this optimized protocol, 103 metabolites were finally identified from a sample of S. coelicolor, which distribute in central metabolic pathways (glycolysis, pentose phosphate pathway and citrate cycle), amino acid, fatty acid, nucleotide metabolic pathways, etc. By comparing the temporal profiles of these metabolites, the amino acid and fatty acid metabolic pathways were found to stay at a high level during stationary phase, therefore, these pathways may play an important role during the transition between the primary and secondary metabolism. An optimized protocol of sample preparation was established and applied for metabolomics analysis of S. coelicolor, 103 metabolites were identified. The temporal profiles of metabolites reveal amino acid and fatty acid metabolic pathways may play an important role in the transition from primary to

  15. Ranitidine preparations on the Belgian market: a comparative study.

    Science.gov (United States)

    Saevels, J; De Braekeleer, K; Corthout, J

    2004-01-01

    Ranitidine preparations formulated as tablets and granules were evaluated with different tests including in vitro dissolution and assay. Previously the analytical methods of these tests were validated according to the guidelines of the European network of Official Medicines Control Laboratories (OMCLs). All examined products complied to the requirements as described in the European, the British and the US Pharmacopoeia and consequently they can be considered as pharmaceutically equivalent.

  16. STUDY ON THE FACTORS AFFECTING REDUCTION CAPACITIES OF ACTIVATED CARBON FIBERS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The reduction adsorption of silver diamminonitrate on different kinds of activated carbonfibers (ACF) has been studied in this paper. The effect of different parameters, including adsorptiontemperature, concentrations of activation agents, and activation time on the silver adsorptioncapacities of activated carbon fibers has been investigated The results show that higher temperaturein which the silver complex interacts with ACF. or higher concentration of activation agent, will makehigher reduction adsorption capacities of ACFs. More over, ACFs activated with phosphoric acidhave higher reduction capacities than those activated with zinc chloride or steam.

  17. NOISE REDUCTION SCHEDULING METHOD IN A SHOP FLOOR AND ITS CASE STUDY

    Institute of Scientific and Technical Information of China (English)

    Liu Fei; Cao Huajun; Zhang Hua; Yuan Chuanping

    2003-01-01

    Noise reduction in a shop floor is one of the important parts of green manufacturing. In a shop floor, machine tools are the main noise sources in a shop floor. A new approach is discovered by investigation that the noise can be obviously reduced in a shop floor by optimizing the scheduling between work pieces and machine tools. Based on the discovery, a new method of noise reduction is proposed. A noise reduction scheduling model in a shop floor is established, and the application of the model is also discussed. A case is studied, which shows that the method and model are practical.

  18. Novel Method to Prepare Magnesium by Aluminothermic Reduction of Magnesia and Calcium Hydroxide at Normal Atmosphere, 1223 K (950 °C)

    Science.gov (United States)

    Zhang, Teng; Du, Shuang-Ming; Sun, Wan-Chang; Zhang, Ju-Mei; Niu, Li-Bin; Zheng, Bin; Hua, Xiao-Hu

    2017-02-01

    An experimental apparatus was designed to investigate the aluminothermic reduction of the mixture of MgO and Ca(OH)2 at normal atmosphere, 1223 K (950 °C), with the molar ratio of MgO:Al:Ca(OH)2 to be 3:2:1, reinforced by high-energy ball milling. The effect of mechanical milling time and content of grinding aid (sodium stearate) on the reduction ratio of MgO were studied. Moreover, the reduzate and reactant activated by ball milling were analyzed by X-ray diffraction, scanning electron microscopy, and energy-dispersive spectrometer analysis. The average grain sizes of Al and MgO activated by ball milling were also calculated by Scherrer formula. The results indicate that the reduction ratio of MgO is increased with increasing mechanical milling time and content of sodium stearate. The high-energy ball milling has good reinforcement on the aluminothermic reduction of MgO. Moreover, the strengthening mechanism of mechanical force on the reaction was further discussed.

  19. Effectiveness of Er:YAG laser in cavity preparation for retrograde filling--in vitro study.

    Science.gov (United States)

    Karlović, Zoran; Grgurević, Lovro; Verzak, Zeljko; Modrić, Vesna-Erika; Sorić, Pjetra; Grgurević, Josko

    2014-06-01

    The purpose of this study was to determine the sealing quality of Super EBA cement in laser prepared root-end cavities in comparison with root-end cavities classically prepared with steel burrs. Two groups of three millimeter root sections were prepared. The first group was prepared with the Er:YAG laser and the second group with a steel burr mounted on a surgical handpiece. The sections were filled with Super EBA cement and tested for leakage with fluid transport techniques. The sealing quality of Super EBA cement in the classically prepared root-end cavities was better, but there was no statistically significant difference between the two preparation techniques. The possible reason for greater leakage in the laser prepared root-end cavities was probably the irregular shape of the root-end cavity.

  20. Preparation and characterization of inexpensive heterogeneous catalysts for air pollution control. Two case studies

    Energy Technology Data Exchange (ETDEWEB)

    Utsumi, Shigenori; Vallejos-Burgos, Fernando E.; Garcia, Ximena; Gordon, Alfredo L. [Department of Chemical Engineering, University of Concepcion, Concepcion (Chile); Campos, Claudia M.; Pecchi, Gina [Department of Physical Chemistry, University of Concepcion, Concepcion (Chile); Radovic, Ljubisa R. [Department of Chemical Engineering, University of Concepcion, Concepcion (Chile); Department of Energy and Geo-Environmental Engineering, The Pennsylvania State University, University Park, PA 16802 (United States)

    2007-05-30

    Relatively inexpensive heterogeneous catalysts for two reactions of great importance in air pollution control, NO reduction and VOC combustion, were prepared and characterized. Apart from their common practical goal and the frequent need for simultaneous removal of air pollutants, these reactions share a similar redox mechanism, in which the formulation of more effective catalysts requires an enhancement of oxygen transfer. For NO reduction, supported catalysts were prepared by adding a metal (Cu, Co, K) using ion exchange (IE) and incipient wetness impregnation (IWI) to chars obtained from pyrolysis of a subbituminous coal. The effects of pyrolysis temperature, between 550 and 1000 C, on selected catalyst characteristics (e.g., BET surface area, XRD spectrum, support reactivity in O{sub 2}) are reported. For IE catalysts, the surface area increased in the presence of the metals while the opposite occurred for IWI catalysts. For the Co-IE catalysts, the highest surface area was obtained at 700 C. The XRD results showed that, except for Cu (which exhibited sharp Cu{sup 0} peaks), the catalysts may be highly dispersed (or amorphous) on the carbon surface. For the C-O{sub 2} reaction the order of (re)activity was K >> Co > Cu for IE catalysts and K > Cu > Co for IWI catalysts. For NO reduction the orders were K > Co > Cu (IE catalysts) and Cu > Co > K (IWI catalysts). In all cases the catalytic (re)activity for NO reduction was lower than that exhibited for the C-O{sub 2} reaction. The K-IE and Cu-IWI catalysts appeared to be the most promising ones, although further improvements in catalytic activity will be desirable. Some surprising results regarding CO and CO{sub 2} selectivity are also reported, especially for Co catalysts. In VOC combustion, the effect of the nature of ion B (Fe and Ni) on the partial substitution of ion A (Ca for La) in ABO{sub 3} perovskites (e.g., LaFeO{sub 3} and LaNiO{sub 3}) and on their catalytic activity was studied. The perovskite

  1. Insurance, Public Assistance, and Household Flood Risk Reduction: A Comparative Study of Austria, England, and Romania.

    Science.gov (United States)

    Hanger, Susanne; Linnerooth-Bayer, Joanne; Surminski, Swenja; Nenciu-Posner, Cristina; Lorant, Anna; Ionescu, Radu; Patt, Anthony

    2017-08-17

    In light of increasing losses from floods, many researchers and policymakers are looking for ways to encourage flood risk reduction among communities, business, and households. In this study, we investigate risk-reduction behavior at the household level in three European Union Member States with fundamentally different insurance and compensation schemes. We try to understand if and how insurance and public assistance influence private risk-reduction behavior. Data were collected using a telephone survey (n = 1,849) of household decisionmakers in flood-prone areas. We show that insurance overall is positively associated with private risk-reduction behavior. Warranties, premium discounts, and information provision with respect to risk reduction may be an explanation for this positive relationship in the case of structural measures. Public incentives for risk-reduction measures by means of financial and in-kind support, and particularly through the provision of information, are also associated with enhancing risk reduction. In this study, public compensation is not negatively associated with private risk-reduction behavior. This does not disprove such a relationship, but the negative effect may be mitigated by factors related to respondents' capacity to implement measures or social norms that were not included in the analysis. The data suggest that large-scale flood protection infrastructure creates a sense of security that is associated with a lower level of preparedness. Across the board there is ample room to improve both public and private policies to provide effective incentives for household-level risk reduction. © 2017 The Authors Risk Analysis published by Wiley Periodicals, Inc. on behalf of Society for Risk Analysis.

  2. Study on fluorouracil–chitosan nanoparticle preparation and its antitumor effect

    Directory of Open Access Journals (Sweden)

    Gaimin Chen

    2016-05-01

    Full Text Available To successfully prepare fluorouracil–chitosan nanoparticles, and further analyze its anti-tumor activity mechanism, this paper makes a comprehensive study of existing preparation prescription and makes a detailed analysis of fluorouracil–chitosan in vitro release and pharmacodynamic behavior of animals. Two-step synthesis method is adopted to prepare 5-FU–CS–mPEG prodrugs, and infrared, 1H NMR and differential thermal analysis are adopted to analyze characterization synthetic products of prepared drugs. To ensure clinical efficacy of prepared drugs, UV spectrophotometry is adopted for determination of drug loading capacity of prepared drugs, transmission electron microscopy is adopted to observe the appearance, dynamic dialysis method is used to observe in vitro drug release of prepared drugs and fitting of various release models is done. Anti-tumor effect is studied via level of animal pharmacodynamics. After the end of the experiment, tumor inhibition rate, spleen index and thymus index of drugs are calculated. Experimental results show that the prepared drugs are qualified in terms of regular shape, dispersion, drug content, etc. Animal pharmacodynamics experiments have shown that concentration level of drug loading capacity of prepared drugs has a direct impact on anti-tumor rate. The higher the concentration, the higher the anti-tumor rate. Results of pathological tissue sections of mice show that the prepared drugs cause varying degrees of damage to receptor cells, resulting in cell necrosis or apoptosis problem. It can thus be concluded that ion gel method is an effective method to prepare drug-loading nanoparticles, with prepared nanoparticles evenly distributed in regular shape which demonstrate good slow-release characteristics in receptor vitro and vivo. At the same time, after completion of drug preparation, relatively strong anti-tumor activity can be generated for the receptor, so this mode of preparation enjoys broad

  3. Magnitudes of biomarker reductions in response to controlled reductions in cigarettes smoked per day: a one-week clinical confinement study.

    Science.gov (United States)

    Theophilus, Eugenia H; Coggins, Christopher R E; Chen, Peter; Schmidt, Eckhardt; Borgerding, Michael F

    2015-03-01

    Tobacco toxicant-related exposure reduction is an important tool in harm reduction. Cigarette per day reduction (CPDR) occurs as smokers migrate from smoking cigarettes to using alternative tobacco/nicotine products, or quit smoking. Few reports characterize the dose-response relationships between CPDR and effects on exposure biomarkers, especially at the low end of CPD exposure (e.g., 5 CPD). We present data on CPDR by characterizing magnitudes of biomarker reductions. We present data from a well-controlled, one-week clinical confinement study in healthy smokers who were switched from smoking 19-25 CPD to smoking 20, 10, 5 or 0 CPD. Biomarkers were measured in blood, plasma, urine, and breath, and included smoke-related toxicants, urine mutagenicity, smoked cigarette filter analyses (mouth level exposure), and vital signs. Many of the biomarkers (e.g., plasma nicotine) showed strong CPDR dose-response reductions, while others (e.g., plasma thiocyanate) showed weaker dose-response reductions. Factors that lead to lower biomarker reductions include non-CPD related contributors to the measured response (e.g., other exposure sources from environment, life style, occupation; inter-individual variability). This study confirms CPDR dose-responsive biomarkers and suggests that a one-week design is appropriate for characterizing exposure reductions when smokers switch from cigarettes to new tobacco products.

  4. The Preparation of Cognitively Agile Principals for Turnaround Schools: A Leadership Preparation Programme Study

    Science.gov (United States)

    Reyes-Guerra, Daniel; Pisapia, John; Mick, Annie

    2016-01-01

    The purpose of this study was to examine the ability of two educational leadership university programmes to improve the cognitive agility of their graduates. The research looked to discover whether the aspiring principals exited the programmes with an increased ability to employ cognitive agility--the ability to use the multiple thinking skills of…

  5. Preparation and release study of Triclosan in polyethylene/Triclosan anti-bacterial blend.

    Science.gov (United States)

    Kamalipour, Jamshid; Masoomi, Mahmood; Khonakdar, Hossein Ali; Razavi, Seyed Mohammad Reza

    2016-09-01

    In this study, medium density polyethylene (MDPE) incorporated with Triclosan antibacterial substance has been prepared and Triclosan release rate was investigated. The crystallinity level and matrix polarity, as two significant parameters in antibacterial release control, were studied. Triclosan, a well-established widespread antibacterial agent, was incorporated into medium density polyethylene (MDPE) and Maleic anhydride grafted polyethylene (PE-g-MA) was used to change the polarity of the MDPE matrix. A masterbatch of 10wt% Triclosan incorporated with the MDPE and various PE-g-MA concentrations were prepared using an internal mixer. Then the masterbatch was diluted in the MDPE matrix to produce compounds with 0.1, 0.5, and1wt% Triclosan via twin screw extruder. The compounds were molded by compression molding method and then were cooled in three different cooling rate methods: isothermal cooling (I), quenching (Q),and moderate 5-10°C/min cooling rate (M). Cooling rate effects on crystallinity level were investigated applying sample density measurement. UV-vis absorption spectroscopy was used to probe the release of Triclosan. Antibacterial properties of the compounds against Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus were measured. The results showed that by addition of PE-g-MA, Triclosan release rate was increased. It was confirmed that the sample crystallinity was decreased by the cooling rate enhancement. The results also showed that quenched samples indicated higher release of Triclosan. Cooling rate reduction and raising the polarity increased the release of Triclosan and improved the antibacterial properties of the compounds.

  6. STUDY ON PREPARATION OF UNIFORM POLYSTYRENE HOLLOW PARTICLES

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    IntmductionHOllow Particles have many attractivecharacteristiCS, for example, low dewi and thermalinsulation due to itS small air void, and Ope opacitywhich is used for paint formulation, resin comPOrts,and face foundation. They can be used in variousfields such as Paint, ink, and paper industrics. Hollowparticles have been Prepared by utilizing Phaseseparation in the Presence Of a cyDSS-linking agent byseeded POlymerization. Okubo et al.lll used their"dynamic swelling teChaique" followed by seededPOlymeriz...

  7. Preparation and study of heterojunctions based on chalcogenide glassy semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kornev, K.P. [Kaliningrad State Univ., Kaliningrad (Russian Federation); Korneva, I.P. [Baltic Fishing Fleet State Academy, Kaliningrad (Russian Federation)

    2005-07-01

    Four types of heterojunctions were prepared: SnO{sub 2}-As{sub 2}(Se{sub 0.9}Te{sub 0.1}){sub 3}, SnO{sub 2}-(As{sub 0.67}Sb{sub 0.33}){sub 2}Se{sub 3}, n-GaAs-As{sub 2}Se{sub 3} and n-GaAs-As{sub 2}S{sub 3}. For all samples I-V characteristics and photosensitivity spectra were obtained. These heterostructures can be used for manufacturing rectifying devices and photoreceivers. (orig.)

  8. Preparation, temperature dependent structural, molecular dynamics simulations studies and electrochemical properties of LiFePO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Rao, R. Prasada, E-mail: mserpr@nus.edu.sg [Department of Materials Science and Engineering, National University of Singapore, 117576 (Singapore); Reddy, M.V. [Department of Materials Science and Engineering, National University of Singapore, 117576 (Singapore); Department of Physics, National University of Singapore, 117542 (Singapore); Adams, S. [Department of Materials Science and Engineering, National University of Singapore, 117576 (Singapore); Chowdari, B.V.R. [Department of Physics, National University of Singapore, 117542 (Singapore)

    2015-06-15

    Highlights: • LiFePO{sub 4} compound was prepared by carbothermal reduction method. • In-situ XRD studies were carried out on LiFePO{sub 4} at various temperatures. • Dedicated imperial potentials used to explain the variation of lattice constants. • It exhibited reversible capacity of 140 (±5) mAh g{sup −1}, stable up to 400 cycles. - Abstract: LiFePO{sub 4} was prepared using carbothermal reduction method. In-situ temperature dependent structural studies were carried using X-ray diffraction. Molecular dynamics simulations were conducted for the LiFePO{sub 4} using empirical potentials developed using bond valence approach to investigate the structural variations. Electrochemical behaviour of LiFePO{sub 4} was evaluated using cyclic voltammetry and galvanostatic cycling studies at room temperature. Charge–discharge cycling studies showed a reversible capacities 140 (±5) mAh g{sup −1} at the end of 50th cycle and these capacity values were stable up to 400 cycles and almost nil capacity fade between 50 and 400 cycles, showing excellent capacity retention, low capacity fading. The cyclic voltammetry studies showed a main cathodic and anodic redox peaks at 3.34 and 3.5 V vs. Li, respectively.

  9. Guidelines for contingency planning NASA (National Aeronautics and Space Administration) ADP security risk reduction decision studies

    Science.gov (United States)

    Tompkins, F. G.

    1984-01-01

    Guidance is presented to NASA Computer Security Officials for determining the acceptability or unacceptability of ADP security risks based on the technical, operational and economic feasibility of potential safeguards. The risk management process is reviewed as a specialized application of the systems approach to problem solving and information systems analysis and design. Reporting the results of the risk reduction analysis to management is considered. Report formats for the risk reduction study are provided.

  10. Study of nonlinear behaviors and modal reductions for friction destabilized systems. Application to an elastic layer

    Science.gov (United States)

    Loyer, A.; Sinou, J.-J.; Chiello, O.; Lorang, X.

    2012-02-01

    As noise reduction tends to be part of environmental directives, predicting squeal noise generated by disc brakes is an important industrial issue. It involves both the transient and stationary nonlinear dynamics of self-excited systems with frictional contact. Time simulation of the phenomenon is an attractive option for reducing experiment costs. However, since such computations using full finite element models of industrial disc brake systems is time-consuming, model reduction has to be performed. In this paper, both the transient and stationary nonlinear behaviors of the friction destabilized system and the effect of dynamical reduction on the nonlinear response of a simple friction destabilized system are carried out. The first part provides a description of the general modeling retained for friction destabilized systems. Then, discretization and solving processes for the stability analysis and the temporal evolution are presented. The third part presents an analysis of a sliding elastic layer for different operating conditions, in order to better understand the nonlinear behavior of such systems. Finally, spatial model reduction is performed with different kinds of reduction bases in order to analyze the different effects of modal reductions. This clearly shows the necessity of including static modes in the reduction basis and that nonlinear interactions between unstable modes are very difficult to represent with reduced bases. Finally, the proposed model and the associated studies are intended to be the benchmark cases for future comparison.

  11. Intraocular pressure variations during zygomatic fracture reduction and fixation: a clinical study.

    LENUS (Irish Health Repository)

    Murray, Dylan J

    2012-02-03

    BACKGROUND: The reduction of midface fractures has been associated with the rare but devastating complication of blindness. An increase in intraocular pressure is important in the mechanism of blindness in this setting. In this study, the authors assessed the intraocular pressure in patients who underwent zygomatic fracture reduction (with or without fixation). METHODS: Using applanation tonometry, 29 patients underwent intraocular pressure measurements before, during, and after fracture fixation. The contralateral pressures were measured and used as the control. RESULTS: There were 29 patients with a mean age of 35 years, and the mean time to surgery was 5 days. Preoperatively, all patients had normal intraocular pressures and normal visual acuity. All patients underwent a Gillies lift and 18 patients required open reduction and fixation of the frontozygomatic suture (n = 4) or the infraorbital margin (n = 2), and the remainder (n = 12) required fixation of both points. There was no statistically significant increase in the intraocular pressures following the reduction of uncomplicated zygomatic fractures. Statistically significant pressure reductions were noted immediately after reduction and fixation. CONCLUSIONS: The surgical reduction of uncomplicated zygomatic fractures has no adverse effect on the intraocular pressure. It is the authors\\' opinion that adjunctive measures to reduce the pressures are unnecessary.

  12. Facile preparation of ordered mesoporous MnCo2O4 for low-temperature selective catalytic reduction of NO with NH3

    Science.gov (United States)

    Qiu, Mingying; Zhan, Sihui; Yu, Hongbing; Zhu, Dandan; Wang, Shengqiang

    2015-01-01

    Ordered mesoporous MnCo2O4 nanomaterials were successfully prepared through the nanocasting route using SBA-15 and KIT-6 as hard templates. These mesoporous nanomaterials were characterized using XRD, BET, TEM, NH3-TPD, H2-TPR, NO-TPD, XPS and DRIFT. The low temperature selective catalytic reduction (SCR) activity of NO with NH3 was investigated, which revealed that 3D-MnCo2O4 using KIT-6 as a template can totally clean all NO over a wide temperature range of 100-250 °C with a gas hourly space velocity (GHSV) of 32 000 h-1, while 2D-MnCo2O4 with SBA-15 as a template had 95% conversion rate at the same condition. 3D-MnCo2O4 showed the best performance to clean NO due to its typical three-dimensional porous structure, large specific surface area, abundant active surface oxygen species and Lewis acid sites. All the results indicate that a novel, cheap catalyst for catalytic removal of NO can be designed by controlling the morphology at the nanoscale.Ordered mesoporous MnCo2O4 nanomaterials were successfully prepared through the nanocasting route using SBA-15 and KIT-6 as hard templates. These mesoporous nanomaterials were characterized using XRD, BET, TEM, NH3-TPD, H2-TPR, NO-TPD, XPS and DRIFT. The low temperature selective catalytic reduction (SCR) activity of NO with NH3 was investigated, which revealed that 3D-MnCo2O4 using KIT-6 as a template can totally clean all NO over a wide temperature range of 100-250 °C with a gas hourly space velocity (GHSV) of 32 000 h-1, while 2D-MnCo2O4 with SBA-15 as a template had 95% conversion rate at the same condition. 3D-MnCo2O4 showed the best performance to clean NO due to its typical three-dimensional porous structure, large specific surface area, abundant active surface oxygen species and Lewis acid sites. All the results indicate that a novel, cheap catalyst for catalytic removal of NO can be designed by controlling the morphology at the nanoscale. Electronic supplementary information (ESI) available: Low-angle XRD

  13. Nanocrystalline Fe{sub 1-x}Co{sub x}Sn{sub 2} solid solutions prepared by reduction of salts in tetraethylene glycol

    Energy Technology Data Exchange (ETDEWEB)

    Nwokeke, Uche G. [Laboratorio de Quimica Inorganica, Universidad de Cordoba, Edificio C3, Campus de Rabanales, 14071 Cordoba (Spain); Chadwick, Alan V. [Functional Materials Group, School of Physical Sciences, University of Kent, Canterbury, Kent CT2 7NH (United Kingdom); Alcantara, Ricardo [Laboratorio de Quimica Inorganica, Universidad de Cordoba, Edificio C3, Campus de Rabanales, 14071 Cordoba (Spain); Alfredsson, Maria [Functional Materials Group, School of Physical Sciences, University of Kent, Canterbury, Kent CT2 7NH (United Kingdom); Tirado, Jose L., E-mail: iq1ticoj@uco.es [Laboratorio de Quimica Inorganica, Universidad de Cordoba, Edificio C3, Campus de Rabanales, 14071 Cordoba (Spain)

    2011-02-10

    Research highlights: > New nanoparticulate materials in the ternary system Fe{sub 1-x}Co{sub x}Sn{sub 2} are reported. > The electrochemical behaviour of the intermediate nano-Fe{sub 1-x}Co{sub x}Sn{sub 2} compositions is better than the corresponding micro-CoSn{sub 2} and FeSn{sub 2}. > The samples that contain iron form Li{sub x}Sn phases during the discharge of the cell and exhibit capacities over 500 mAh g{sup -1} during the first 30 cycles. > The partial replacement of cobalt by iron could moderate the potential cost and toxicity of the materials in Li-ion batteries. - Abstract: In an effort to improve the electrochemical performance of tin intermetallic phases as electrode active material for lithium-ion batteries, Fe{sub 1-x}Co{sub x}Sn{sub 2} solid solutions with x = 0.0, 0.25, 0.3, 0.5, 0.6 and 0.8 were prepared by chemical reduction in tetraethylene glycol. Precise control of the synthesis conditions allowed single-phase nanocrystalline materials to be prepared, with particle diameters of about 20 nm and cubic, nanorods, and U-shaped morphologies. The substitution of iron by cobalt induced a contraction of the unit cell volume. The hyperfine parameters of the {sup 57}Fe Moessbauer spectra were sensitive to the Co/Fe substitution and revealed a superparamagnetic behaviour. In lithium cells nanocrystalline Fe{sub 1-x}Co{sub x}Sn{sub 2} active materials delivered reversible capacities above 500 mAh g{sup -1} that depended on the composition and cycling conditions. The intermediate compositions exhibit better electrochemical performance than the end compositions CoSn{sub 2} and FeSn{sub 2}.

  14. 光化学还原法制备纳米银溶胶%Preparation of Nano-silver Sol by Photochemical Reduction Method

    Institute of Scientific and Technical Information of China (English)

    张伟; 谈发堂; 乔学亮; 陈建国

    2012-01-01

    Nano-silver sol with good dispersibility and narrow panicle size distribution was prepared by photochemical reduction of silver ammonia solution precursor with polyvinylpyrrolidone(PVP) as protective agent. Transmission electron microscope(TEM) and UV-Vis were also employed to characterize the prepared nano-silver soL The results indicate that UV irradiation time and the concentration of PVP both have obvious influence for this reaction. A good morphology and dispersibility of silver nano-sol could be synthesized after irradiation 30min, when the mole ratio of PVP/[Ag(NH3 )2]+ in reaction solution equal to 50. Furthermore, the process of synthesizing silver nano-sol does not contain any toxic additive, which makes the product possesse a wide application in the future.%采用光化学还原法,以银氨溶液为前驱体,PVP为保护剂制备分散性良好和粒径分布窄的纳米银溶胶.利用透射电子显微镜(TEM)和紫外-可见分光光度计(UV-Vis)对纳米银溶胶进行表征.结果表明,紫外光照时间和PVP浓度都对该反应有明显的影响,在[Ag(NH3)2]+浓度为1mmol/L,n(PVP)/n([Ag(NH3)2]+)=50时,反应30min就可以生成理想的纳米银溶胶.此外,该方法没有使用有毒添加剂,制备的纳米银溶胶更为安全,从而可以应用在更为广阔的领域.

  15. Nitrate conversion and supercritical fluid extraction of UO{sub 2}-CeO{sub 2} solid solution prepared by an electrolytic reduction-coprecipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, L.Y. [Tsinghua Univ., Beijing (China). Inst. of Nuclear and New Energy Technology; China Institute of Atomic Energy, Beijing (China); Duan, W.H.; Wen, M.F.; Xu, J.M.; Zhu, Y.J. [Tsinghua Univ., Beijing (China). Inst. of Nuclear and New Energy Technology

    2014-04-01

    A low-waste technology for the reprocessing of spent nuclear fuel (SNF) has been developed recently, which involves the conversion of actinide and lanthanide oxides with liquid N{sub 2}O{sub 4} into their nitrates followed by supercritical fluid extraction of the nitrates. The possibility of the reprocessing of SNF from high-temperature gas-cooled reactors (HTGRs) with nitrate conversion and supercritical fluid extraction is a current area of research in China. Here, a UO{sub 2}-CeO{sub 2} solid solution was prepared as a surrogate for a UO{sub 2}-PuO{sub 2} solid solution, and the recovery of U and Ce from the UO{sub 2}-CeO{sub 2} solid solution with liquid N{sub 2}O{sub 4} and supercritical CO{sub 2} containing tri-n-butyl phosphate (TBP) was investigated. The UO{sub 2}-CeO{sub 2} solid solution prepared by electrolytic reduction-coprecipitation method had square plate microstructures. The solid solution after heat treatment was completely converted into nitrates with liquid N{sub 2}O{sub 4}. The XRD pattern of the nitrates was similar to that of UO{sub 2}(NO{sub 3}){sub 2} . 3H{sub 2}O. After 120 min of online extraction at 25 MPa and 50 , 99.98% of the U and 98.74% of the Ce were recovered from the nitrates with supercritical CO{sub 2} containing TBP. The results suggest a promising potential technology for the reprocessing of SNF from HTGRs. (orig.)

  16. Preparation of highly active manganese oxides supported on functionalized MWNTs for low temperature NO{sub x} reduction with NH{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Pourkhalil, Mahnaz [Chemical Engineering Faculty, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Moghaddam, Abdolsamad Zarringhalam, E-mail: zarrin@modares.ac.ir [Chemical Engineering Faculty, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Rashidi, Alimorad [Nanotechnology Research Center, Research Institute of the Petroleum Industry (RIPI), P.O. Box 18745-4163, Tehran (Iran, Islamic Republic of); Towfighi, Jafar [Chemical Engineering Faculty, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Mortazavi, Yadollah [Catalysis and Nanostructured Materials Lab, Chemical Engineering Faculty, Tehran University, P.O. Box 11365-4563, Tehran (Iran, Islamic Republic of)

    2013-08-15

    Manganese oxide catalysts (MnO{sub x}) supported on functionalized multi-walled carbon nanotubes (FMWNTs) for low temperature selective catalytic reduction (LTSCR) of nitrogen oxides (NO{sub x}) with NH{sub 3} in the presence of excess O{sub 2} were prepared by the incipient wetness impregnation method. These catalysts were characterized by N{sub 2} adsorption, Fourier transform infrared spectroscopy (FTIR), transmission electron microscope (TEM), X-ray diffraction (XRD), thermal gravimetric analysis (TGA) and H{sub 2}-temperature programmed reduction (H{sub 2}-TPR) methods. The effects of reaction temperature, MnO{sub x} loading, calcination temperature and calcination time were investigated. The presence of surface nitrate species under moderate calcination conditions may play a favorable role in the LTSCR of NO{sub x} with NH{sub 3}. Under the reaction conditions of 200 °C, 1 bar, NO = NH{sub 3} = 900 ppm, O{sub 2} = 5 vol%, GHSV = 30,000 h{sup −1} and 12 wt% MnO{sub x}, NO{sub x} conversion and N{sub 2} selectivity were 97% and 99.5%, respectively. The SCR activity was reduced in the presence of 100 ppm SO{sub 2} and 2.5 vol% H{sub 2}O from 97% to 92% within 6 h at 200 °C, however such an effect was shown to be reversible by exposing the catalyst to a helium flow for 2 h at 350 °C due to thermal decomposition of ammonium sulphate salts.

  17. Low-temperature selective catalytic reduction of NO with NH₃ over nanoflaky MnOx on carbon nanotubes in situ prepared via a chemical bath deposition route.

    Science.gov (United States)

    Fang, Cheng; Zhang, Dengsong; Cai, Sixiang; Zhang, Lei; Huang, Lei; Li, Hongrui; Maitarad, Phornphimon; Shi, Liyi; Gao, Ruihua; Zhang, Jianping

    2013-10-07

    Nanoflaky MnO(x) on carbon nanotubes (nf-MnO(x)@CNTs) was in situ synthesized by a facile chemical bath deposition route for low-temperature selective catalytic reduction (SCR) of NO with NH₃. This catalyst was mainly characterized by the techniques of X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), N₂ adsorption-desorption analysis, X-ray photoelectron spectroscopy (XPS), H₂ temperature-programmed reduction (H₂-TPR) and NH₃ temperature-programmed desorption (NH₃-TPD). The SEM, TEM, XRD results and N₂ adsorption-desorption analysis indicated that the CNTs were surrounded by nanoflaky MnO(x) and the obtained catalyst exhibited a large surface area as well. Compared with the MnO(x)/CNT and MnO(x)/TiO₂ catalysts prepared by an impregnation method, the nf-MnO(x)@CNTs presented better NH₃-SCR activity at low temperature and a more extensive operating temperature window. The XPS results showed that a higher atomic concentration of Mn(4+) and more chemisorbed oxygen species existed on the surface of CNTs for nf-MnO(x)@CNTs. The H₂-TPR and NH₃-TPD results demonstrated that the nf-MnO(x)@CNTs possessed stronger reducing ability, more acid sites and stronger acid strength than the other two catalysts. Based on the above mentioned favourable properties, the nf-MnO(x)@CNT catalyst has an excellent performance in the low-temperature SCR of NO to N₂ with NH₃. In addition, the nf-MnO(x)@CNT catalyst also presented favourable stability and H₂O resistance.

  18. Preparation of Copper Telluride Films by Co-Reduction of Cu(I) and Te(IV) Ions in Choline Chloride: Ethylene Glycol Ionic Liquid

    Science.gov (United States)

    Golgovici, Florentina; Catrangiu, Adriana-Simona; Stoian, Andrei Bogdan; Anicai, Liana; Visan, Teodor

    2016-07-01

    Cathodic processes of direct co-reduction of Cu+ and Te4+ ions on Pt electrode at 60°C were investigated using cyclic voltammetry and electrochemical impedance spectroscopy techniques. The ionic liquid as background electrolyte consisted of a mixture of choline chloride and ethylene glycol (ChCl-EG 1:2 mol ratio) in which 5-20 mM CuCl and 8 mM TeO2 were dissolved. The voltammograms exhibited the following successive cathodic processes: Cu2+/Cu+ reduction, Te underpotential deposition, simultaneous deposition of Cu metal and CuTe compound, and deposition of Te-rich CuTe compound at the most negative potentials (from -0.5 V to -0.8 V). Corresponding dissolution or oxidation peaks were recorded on the anodic branch. The voltammetric results were confirmed by electrochemical impedance spectra. Copper telluride films have been synthesized on platinum substrate via potentiostatic electrodeposition at 60°C. It was found from atomic force microscopy that CuTe film samples prepared from ChCl-EG + 5 mM CuCl + 8 mM TeO2 ionic liquid have high growth rates. The x-ray diffraction patterns of the deposited films from ChCl-EG + 10 mM CuCl + 8 mM TeO2 ionic liquid indicated the presence of a Cu2Te phase for film deposited at -0.7 V and a Cu0.656Te0.344 phase for film deposited at -0.6 V.

  19. A nutrition and conditioning intervention for natural bodybuilding contest preparation: case study.

    Science.gov (United States)

    Robinson, Scott Lloyd; Lambeth-Mansell, Anneliese; Gillibrand, Gavin; Smith-Ryan, Abbie; Bannock, Laurent

    2015-01-01

    Bodybuilding competitions are becoming increasingly popular. Competitors are judged on their aesthetic appearance and usually exhibit a high level of muscularity and symmetry and low levels of body fat. Commonly used techniques to improve physique during the preparation phase before competitions include dehydration, periods of prolonged fasting, severe caloric restriction, excessive cardiovascular exercise and inappropriate use of diuretics and anabolic steroids. In contrast, this case study documents a structured nutrition and conditioning intervention followed by a 21 year-old amateur bodybuilding competitor to improve body composition, resting and exercise fat oxidation, and muscular strength that does not involve use of any of the above mentioned methods. Over a 14-week period, the Athlete was provided with a scientifically designed nutrition and conditioning plan that encouraged him to (i) consume a variety of foods; (ii) not neglect any macronutrient groups; (iii) exercise regularly but not excessively and; (iv) incorporate rest days into his conditioning regime. This strategy resulted in a body mass loss of 11.7 kg's, corresponding to a 6.7 kg reduction in fat mass and a 5.0 kg reduction in fat-free mass. Resting metabolic rate decreased from 1993 kcal/d to 1814 kcal/d, whereas resting fat oxidation increased from 0.04 g/min to 0.06 g/min. His capacity to oxidize fat during exercise increased more than two-fold from 0.24 g/min to 0.59 g/min, while there was a near 3-fold increase in the corresponding exercise intensity that elicited the maximal rate of fat oxidation; 21% V̇O2max to 60% V̇O2max. Hamstring concentric peak torque decreased (1.7 to 1.5 Nm/kg), whereas hamstring eccentric (2.0 Nm/kg to 2.9 Nm/kg), quadriceps concentric (3.4 Nm/kg to 3.7 Nm/kg) and quadriceps eccentric (4.9 Nm/kg to 5.7 Nm/kg) peak torque all increased. Psychological mood-state (BRUMS scale) was not negatively influenced by the intervention and all values relating to the Athlete

  20. Turbulent Drag Reduction: Studies of Feedback Control and Flow Over Riblets

    Science.gov (United States)

    Choi, Haecheon

    The objective of this study is to explore concepts for control of turbulent boundary layers leading to skin -friction reduction using the direct numerical simulation technique. This report is divided into three parts where three different control methods are investigated; a passive control by longitudinal riblets, an active control by sensing and perturbing structures near the wall, and a feedback control procedure guided by control theory. In PART I significant drag reduction is achieved when the surface boundary condition is modified to suppress the dynamically significant coherent structures present in the wall region. The drag reduction is accompanied with significant reduction in the intensity of the wall -layer structures and reductions in the magnitude of Reynolds shear stress throughout the flow. Two essential drag reduction mechanisms are presented. In PART II mathematical methods of control theory are applied to the problem of control of fluid flow. The procedure of how to cast the problem of controlling turbulence into a problem in optimal control theory is presented through the formalism and language of control theory. Then a suboptimal control and feedback procedure are presented using methods of calculus of variations through the adjoint state and gradient algorithms. This suboptimal feedback control procedure is applied to the distributed and boundary controls of the stochastic Burgers equation. Most cases considered show significant reductions of the costs. In PART III direct numerical simulation is performed to analyze turbulent flow over longitudinal riblets, and to educe the mechanism of drag reduction by riblets. The computed drags on the riblet surfaces are in good agreement with the existing experimental data. Differences in the mean-velocity profile and turbulence quantities are found to be limited to the inner region of the boundary layer. Velocity and vorticity fluctuations as well as the Reynolds shear stresses above the riblets are

  1. A prospective study of short- and long-term cosmetic outcome after reduction mammaplasty from three different perspectives

    DEFF Research Database (Denmark)

    Breiting, Line Bro; Henriksen, Trine Foged; Kalialis, Louise Vennegaard

    2012-01-01

    Numerous studies have examined the outcome of reduction mammaplasty. This study evaluates the cosmetic outcome after reduction mammaplasty from the perspective of the patient, a ward surgeon, and a private practitioner in plastic surgery, and analyzes which factors influence it....

  2. Study for Reduction of Outgassing Property of Adsorbed Water Gas for Improved Surface Finished Titanium Material

    Science.gov (United States)

    Takeda, Masatoshi; Kurisu, Hiroki; Uchida, Takashi; Yamamoto, Setsuo; Ishizawa, Katsunobu; Nomura, Takeru; Eda, Takahiro; Murashige, Nobuyuki

    This paper addresses the development of the surface finishing for a titanium material and the study for the reduction of outgassing property of adsorbed water (H2O) molecules. Developed surface finishing is composed of the buffing for the reduction of the surface roughness and improved chemical polishing for the thick surface oxide layer compared with the chemical polishing so far. The surface roughness of the surface finished titanium material is reduced 35% and the thickness of the surface oxide layer increases by 30%. The total amount of thermal desorbed H2O gas for the new surface finished titanium is reduced 30%. It is considered that the origin for the decrease of the amount of desorption H2O gas is the reduction of the adsorption sites due to the decrease of the surface roughness and the reduction of adsorption energy of H2O gas due to the strong surface oxidation for a titanium material.

  3. Manufacturing cost reductions and ecoefficiency: a relationship based on a case study

    Directory of Open Access Journals (Sweden)

    Rosangela Maria Vanalle

    2014-12-01

    Full Text Available In the search for higher profits or competitiveness, firms have frequently used structured procedures to reduce their costs and expenses. However, the environmental consequences associated to those processes have hardly been considered. Hence, the central purpose of this paper is to show that it is possible to obtain relevant environmental gains even not considering the environmental issues as part of the operational cost reduction efforts. This particular point was verified through a single case study where value analysis was used to obtain manufacturing cost reductions in a company belonging to the Brazilian textile sector. Even not considering environmental aspects as part of the value analysis procedures, when the cost reduction actions were implemented it was possible to confirm that they also brought significant improvements to the environmental conditions, which were measured by the firm ecoefficiency levels before and after the cost reduction implementations. Normal 0 21 false false false PT-BR X-NONE X-NONE

  4. Study on trend analysis of greenhouse gas reduction policy and its countermeasure in Korea: concentrated on transportation sector

    Energy Technology Data Exchange (ETDEWEB)

    Han, Hwa Jin; Oh, So Young [Korea Environment Institute, Seoul (Korea)

    1999-12-01

    The objective of this study is to recommend a countermeasure to climate change and energy saving. It analyzed reduction policies in domestic and abroad relating to the greenhouse gas reduction especially on automobiles among transportation sector, which shows the highest increase rate of greenhouse gas emission among major greenhouse gas emission sector. Then it estimated a reduction capacity for each reduction scenario concentrated on estimable measures with the potential reduction amount. 26 refs., 23 figs., 39 tabs.

  5. Dose reduction potential of iterative reconstruction algorithms in neck CTA-a simulation study.

    Science.gov (United States)

    Ellmann, Stephan; Kammerer, Ferdinand; Allmendinger, Thomas; Brand, Michael; Janka, Rolf; Hammon, Matthias; Lell, Michael M; Uder, Michael; Kramer, Manuel

    2016-10-01

    This study aimed to determine the degree of radiation dose reduction in neck CT angiography (CTA) achievable with Sinogram-affirmed iterative reconstruction (SAFIRE) algorithms. 10 consecutive patients scheduled for neck CTA were included in this study. CTA images of the external carotid arteries either were reconstructed with filtered back projection (FBP) at full radiation dose level or underwent simulated dose reduction by proprietary reconstruction software. The dose-reduced images were reconstructed using either SAFIRE 3 or SAFIRE 5 and compared with full-dose FBP images in terms of vessel definition. 5 observers performed a total of 3000 pairwise comparisons. SAFIRE allowed substantial radiation dose reductions in neck CTA while maintaining vessel definition. The possible levels of radiation dose reduction ranged from approximately 34 to approximately 90% and depended on the SAFIRE algorithm strength and the size of the vessel of interest. In general, larger vessels permitted higher degrees of radiation dose reduction, especially with higher SAFIRE strength levels. With small vessels, the superiority of SAFIRE 5 over SAFIRE 3 was lost. Neck CTA can be performed with substantially less radiation dose when SAFIRE is applied. The exact degree of radiation dose reduction should be adapted to the clinical question, in particular to the smallest vessel needing excellent definition.

  6. A comparative study of different strategies for removal of endotoxins from bacteriophage preparations.

    Science.gov (United States)

    Van Belleghem, Jonas D; Merabishvili, Maya; Vergauwen, Bjorn; Lavigne, Rob; Vaneechoutte, Mario

    2017-01-01

    Bacterial endotoxins have high immunogenicity. Phage biology studies as well as therapeutic phage applications necessitate highly purified phage particles. In this study, we compared combinations of seven different endotoxin removal strategies and validated their endotoxin removal efficacy for five different phages (i.e. four Pseudomonas aeruginosa phages and one Staphylococcus aureus phage). These purification strategies included Endotrap HD column purification and/or CsCl density centrifugation in combination with Endotrap purification, followed by organic solvent (1-octanol), detergent (Triton X-100), enzymatic inactivation of the endotoxin using alkaline phosphatase and CIM monolytic anion exchange chromatography. We show that CsCl density purification of the P. aeruginosa phages, at an initial concentration of 10(12)-10(13)pfu/ml, led to the strongest reduction of endotoxins, with an endotoxin removal efficacy of up to 99%, whereas additional purification methods did not result in a complete removal of endotoxins from the phage preparations and only yielded an additional endotoxin removal efficacy of 23 to 99%, sometimes accompanied with strong losses in phage titer.

  7. Preparation of nanoanatase and its in situ XRD study

    Institute of Scientific and Technical Information of China (English)

    LI Guo-hua; ZHENG Yi-fan; MA Chun-an; TIAN Wei

    2008-01-01

    Phase pure nanoanatase was prepared by sol-hydrolysis of TiCl4 in ammonium sulfate solution. In order to investigate the microstrain effect on nanoanatase transformation, the transformation process of the sample was investigated by in situ XRD. Based on the in situ XRD data, a variation of the diameter and its distribution, and the microstrain of nanotitania particles were estimated with Win XRD software. The results show that the transformation process of nanoanatase can be divided into four steps; a rate competition between the anatase growth and the transformation from anatase to rutile determines the diameter and its size distribution of anatase nanoparticles; and during the phase transformation, the microstrain determines the rates of anatase growth and its transformation.

  8. A Study on Alnico Permanent Magnet Powders Prepared by Atomization

    Institute of Scientific and Technical Information of China (English)

    Changbin SONG; Bocksoo HAN; Ying LI

    2004-01-01

    Alnico powders were prepared by gas atomization process. Composition of the Alnico powders was Fe37.1 Al8.2 Ni17.6-Co26.6 Cu3.3 Ti7.2 (wt pct) which was the same as that of commercially available Alnico magnets. Average particle size of the powders was 119μm. Effects of heat treatment in magnetic field on magnetic properties of the powders were investigated. The optimum process of heat treatment was found as follows, heated at 870℃ for 1 min first, then cooled down to 700℃ at cooling rate 0.3℃/s in magnetic field, and finally aged isothermally for 4 h.Magnetic properties of the Alnico powders were measured and the results were that intrinsic coercivity iHc was 1.0kOe and remanence Mr was 36.5 emu/g.

  9. A New Technique for Preparation of High-Grade Titanium Slag from Titanomagnetite Concentrate by Reduction-Melting-Magnetic Separation Processing

    Science.gov (United States)

    Lv, Chao; Yang, Kun; Wen, Shu-ming; Bai, Shao-jun; Feng, Qi-cheng

    2017-08-01

    This paper proposes a new technique for preparation of high-grade titanium slag from Panzhihua vanadium titanomagnetite concentrate by reduction-melting-magnetic separation processing. Chemical analysis, x-ray diffraction, and scanning electron microscopy in conjunction with energy-dispersive spectroscopy were used to characterize the samples. The effective separation of iron and titanium slag could be realized by melting metallized pellets at 1550°C for 60 min with the addition of 1% CaO (basicity of 1.1) and 2% graphite powder. The small iron particles embedded in the slag could be removed by fine grinding and magnetic separation process. The grade of TiO2 in the obtained high-grade titanium slag reached 60.68% and the total recovery of TiO2 was 91.25%, which could be directly applied for producing titanium white by the sulfuric acid process. This technique provides an alternative method to use vanadium titanomagnetite concentrate of the Panzhihua area in China.

  10. Preparation of CdS@CeO2 core/shell composite for photocatalytic reduction of CO2 under visible-light irradiation

    Science.gov (United States)

    Ijaz, Sana; Ehsan, Muhammad Fahad; Ashiq, Muhammad Naeem; Karamat, Nazia; He, Tao

    2016-12-01

    Present work demonstrates fabrication of CdS@CeO2 core/shell composite and its application in the photocatalytic reduction of CO2 under visible-light irradiation (λ ≥ 420 nm). CdS@CeO2 composite has been successfully prepared by two-step chemical method, while CeO2 and CdS have been synthesized by one-step hydrothermal method. X-ray diffraction analysis confirms the formation of fluorite cubic structure of CeO2 and cubic phase of CdS. High resolution transmission electron microscopy and scanning electron microscopy reveal the microsphere morphology of CdS, while CeO2 (shell) is in the form of spherical particles that surround the CdS (core) in case of the composite. X-ray photoelectron spectroscopy has been used to confirm the composition, oxidation state of the elements and valance band of the obtained materials. The CdS@CeO2 core/shell composite and CdS can convert CO2 into methane and methanol under visible-light irradiation. The CdS@CeO2 composite shows higher yield for both methane and methanol than CdS due to low recombination rate of photogenerated electron/hole pairs, as well as a larger BET specific surface area. Moreover, the CdS@CeO2 core/shell composite also shows improved stability upon photocatalysis.

  11. Preparation of multilocation reduction-sensitive core crosslinked folate-PEG-coated micelles for rapid release of doxorubicin and tariquidar to overcome drug resistance

    Science.gov (United States)

    Yi, Xiaoqing; Zhao, Dan; Zhang, Quan; Xu, Jiaqi; Yuan, Gongdao; Zhuo, Renxi; Li, Feng

    2017-02-01

    Herein, we prepared folate-targeting core crosslinked polymeric micelles (CCL/FA) containing multiple disulfide bonds located at the interface and core of the micelles to co-deliver doxorubicin (DOX) and the P-glycoprotein (P-gp) inhibitor tariquidar (TQR) for reversing drug resistance. The stability and redox-responsive behavior of the CCL/FA micelles was evaluated through the changes in morphology, molecular weight and hydrodynamic size. On the one hand, the micelles possessed good stability, which led to the suppression of drug release from the CCL micelles in the physiological environment. On the other hand, under reductive conditions, the CCL micelles collapsed rapidly and accelerated drug release markedly. In vitro cytotoxicity measurements, combined with confocal laser scanning microscopy (CLSM) and flow cytometry, confirmed that the dual-drug-loaded micelles exhibited obviously higher cytotoxicity to MCF-7/ADR-resistant cells than free DOX · HCl, single-drug loaded CCL micelles and nontargeted CCL micelles. The results imply that co-delivering DOX and TQR by CCL/FA micelles may be a promising way of overcoming multidrug resistance in tumor treatments.

  12. Preparation and electrochemical properties of a LiFePO{sub 4}/C composite cathode material by a polymer-pyrolysis-reduction method

    Energy Technology Data Exchange (ETDEWEB)

    Yang Kerun; Lin Ziji [Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, Sichuan 610041 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Hu Xuebu [Department of Chemistry and Materials, Sichuan Normal University, Chengdu, Sichuan 610066 (China); Deng Zhenghua, E-mail: zhdeng@cioc.ac.c [Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, Sichuan 610041 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Zhongke Laifang Power Science and Technology Co., Ltd., Chengdu, Sichuan 610041 (China); Suo Jishuan [Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, Sichuan 610041 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China)

    2011-02-28

    A LiFePO{sub 4}/C composite was successfully prepared by a polymer-pyrolysis-reduction method, using FePO{sub 4}.2H{sub 2}O and lithium polyacrylate (PAALi) as raw materials. The structure of the LiFePO{sub 4}/C composites was investigated by X-ray diffraction (XRD). The micromorphology of the precursor and LiFePO{sub 4}/C powders was observed using scanning electron microscopy (SEM), and the in situ coating of carbon on the particles was observed by transmission electron microscopy (TEM). Furthermore, the electrochemical properties were evaluated by cyclic voltammograms (CVs), electrochemical impedance spectra (EIS) and constant current charge/discharge cycling tests. The results showed that the sample synthesized at 700 {sup o}C had the best electrochemical performance, exhibiting initial discharge capacities of 157, 139 and 109 mAh g{sup -1} at rates of 0.1, 1 and 5 C, respectively. Moreover, the sample presented excellent capacity retention as there was no significant capacity fade after 50 cycles.

  13. A Qualitative Study of Bottlenecks and Causes of Fractions for Dedicated Incomes of Health Centers and Solutions for their Reduction

    Science.gov (United States)

    Tabrizi, Jafar Sadegh; Alidoost, Saeide; Abdolahi, Hossein Mashhadi

    2016-01-01

    Background: Primary health care is one of effective approaches for improving public health. Providing optimal cares requires supplication of various resources such as financial resources. “Fractions of incomes” in health centers is one of the remarkable problems for the domain of financial resources management in Iran. This study was aimed to identify bottlenecks and causes of fractions for incomes in health centers and solutions for their reduction. Methods: The current study was conducted in a qualitative phenomenology method in East Azerbaijan province of Iran in 2014. Data collection method was focus group discussion and semi-structured interview. Purposive sampling was used for selecting participants. Focus group discussions and interviews were conducted based on pre-prepared guidance and continued till data saturation. Validity of guidance was approved by qualitative studies experts. Data were analyzed using content analysis method. Results: Based on the opinions of participants, two and six themes were respectively extracted for bottlenecks of fractions and causes and solutions for their reduction. Themes for bottlenecks of fractions included cash (monetary) and non-cash (non-monetary) fractions and themes for causes and solutions included causes and solutions for fractions per capita, insurance deductions, fractions related to sending documents, registration fractions, discounts fractions, and incomplete deposit of cash incomes. Conclusion: All cash and non-cash incomes of health centers are subject to fractions. The causes of fractions are related to the whole process of converting services to incomes and insurance requirements. Identified solutions and interventions also focus on these areas.

  14. Barriers for progress in salt reduction in the general population. An international study.

    Science.gov (United States)

    Newson, R S; Elmadfa, I; Biro, Gy; Cheng, Y; Prakash, V; Rust, P; Barna, M; Lion, R; Meijer, G W; Neufingerl, N; Szabolcs, I; van Zweden, R; Yang, Y; Feunekes, G I J

    2013-12-01

    Salt reduction is important for reducing hypertension and the risk of cardiovascular events, nevertheless worldwide salt intakes are above recommendations. Consequently strategies to reduce intake are required, however these require an understanding of salt intake behaviours to be effective. As limited information is available on this, an international study was conducted to derive knowledge on salt intake and associated behaviours in the general population. An online cohort was recruited consisting of a representative sample from Germany, Austria, United States of America, Hungary, India, China, South Africa, and Brazil (n=6987; aged 18-65 years; age and gender stratified). Participants completed a comprehensive web-based questionnaire on salt intake and associated behaviours. While salt reduction was seen to be healthy and important, over one third of participants were not interested in salt reduction and the majority were unaware of recommendations. Salt intake was largely underestimated and people were unaware of the main dietary sources of salt. Participants saw themselves as mainly responsible for their salt intake, but also acknowledged the roles of others. Additionally, they wanted to learn more about why salt was bad for health and what the main sources in the diet were. As such, strategies to reduce salt intake must raise interest in engaging in salt reduction through improving understanding of intake levels and dietary sources of salt. Moreover, while some aspects of salt reduction can be globally implemented, local tailoring is required to match level of interest in salt reduction. These findings provide unique insights into issues surrounding salt reduction and should be used to develop effective salt reduction strategies and/or policies. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. Comparison of image quality in head CT studies with different dose-reduction strategies

    DEFF Research Database (Denmark)

    Johansen, Jeppe; Nielsen, Rikke; Fink-Jensen, Vibeke;

    The number of multi-detector CT examinations is increasing rapidly. They allow high quality reformatted images providing accurate and precise diagnosis at maximum speed. Brain examinations are the most commonly requested studies, and although they come at a lower effective dose than body CT, can...... account to a considerable radiation dose as many patients undergo repeated studies. Therefore, various dose-reduction strategies are applied such as automated tube current and voltage modulation and recently different iterative reconstruction algorithms. However, the trade-off of all dose......-reduction maneuvers is reduction of image quality due to image noise or artifacts. The aim of our study was therefore to find the best diagnostic images with lowest possible dose. We present results of dose- and image quality optimizing strategies of brain CT examinations at our institution. We compare sequential...

  16. Course of disability reduction during a pain rehabilitation program : a prospective clinical study

    NARCIS (Netherlands)

    Waterschoot, Franka P. C.; Dijkstra, Pieter U.; Geertzen, Jan H. B.; Reneman, Michiel F.

    2015-01-01

    The aim of this study was to analyze the course of reduction of disability during a pain rehabilitation program (PRP) and factors influencing this course. A prospective cohort study was carried out. All patients with chronic musculoskeletal pain treated in a PRP between March 2010 and December 2010

  17. Kinetics study of carbon raiser on the reduction of nickel laterite from Pomalaa, Southeast Sulawesi

    Science.gov (United States)

    Petrus, H. T. B. M.; Rhamdani, A. R.; Putera, A. D. P.; Warmada, I. W.; Yuliansyad, A. T.; Perdana, I.

    2016-11-01

    As one of the top ten on nickel laterite ore resources in the world, Indonesia must have been initiating the nickel processing in total amount of about 1.5 million tonnes. In regard to the low nickel laterite processing, one of the possible product is nickel pig iron (NPI) needed for the stainless steel industries. In this study carbon raiser that is waste from oil industries was used to replace metalurgical coke. The kinetic of nickel laterite reduction using carbon raiser was studied and compared with anthrasite coal. In this work, the author conducted the reduction of nickel laterite ores by both carbon raiser and anthrasite coal as reductant, in air and CO2 atmosphere, within the temperature ranged from 800°C and 1000°C. Two models were applied, sphere particle geometry model and Ginstling-Brounhstein diffusion model, to study the kinetic parameters. The results indicated that type of reductants and reduction atmosphere greatly influence the kinetic parameters. The obtained values of activation energy were varied between 17.44-18.12 kcal/mol.

  18. Salt microspheres and potassium chloride usage for sodium reduction: Case study with sushi.

    Science.gov (United States)

    Đorđević, Đani; Buchtová, Hana; Macharáčková, Blanka

    2017-01-01

    The aim of the study was to estimate possibilities of salt substitutes usage in the preparation of two sushi types (nigiri and maki) prepared with different seafood (salmon: Salmo salar, tuna: Thunnus albacares, and shrimp: Pleoticus muelleri). Potassium chloride (Mary samples), Soda-Lo (hollowed microsphere of regular salt crystals), and regular salt (sodium chloride) were used in the experiment. Sushi samples (n = 1960) were evaluated by 40 trained panelists who noticed that maki shrimp samples prepared with Mary salt had higher bitterness (21.48 ± 28.01) in comparison with 2% sodium chloride (7.91 ± 8.80). The saltiness was lower in nigiri tuna prepared with Mary (49.59 ± 17.47) than 2% sodium chloride (61.11 ± 15.75). The study clearly showed the possibility of lowering sodium content in sushi meal with the usage of salt substitutes, with emphasis that Soda-Lo should be considered as a better option due to the retention of sensory properties in sushi samples prepared with this salt substitute.

  19. Study of nano-nitramine explosives: preparation, sensitivity and application

    Directory of Open Access Journals (Sweden)

    Jie Liu

    2014-06-01

    Full Text Available Nano-nitramine explosives (RDX, HMX, CL-20 are produced on a bi-directional grinding mill. The scanning electron microscope (SEM observations show that the prepared particles are semi-spherical, and the narrow size distributions are characterized using the laser particle size analyzer. Compared with the micron-sized samples, the nano-products show obvious decrease in friction and impact sensitivities. In the case of shock sensitivities, nano-products have lower values by 59.9% (RDX, 56.4% (HMX, and 58.1% (CL-20, respectively. When nano-RDX and nano-HMX are used in plastic bonded explosives (PBX as alternative materials of micron-sized particles, their shock sensitivities are significantly decreased by 24.5% (RDX and 22.9% (HMX, and their detonation velocities are increased by about 1.7%. Therefore, it is expected to promote the application of nano-nitramine explosives in PBXs and composite modified double-based propellants (CMDBs so that some of their properties would be improved.

  20. Further studies on preparation and properties of phagocytin.

    Science.gov (United States)

    HIRSCH, J G

    1960-03-01

    PHAGOCYTIN AND HISTONE DIFFER SIGNIFICANTLY IN THE FOLLOWING REGARDS: (a) the bactericidal action of histone is rapidly lost on peptic digestion, while that of phagocytin is but little affected; (b) the lethal effect of phagocytin on coliform bacteria is much more resistant than that of histone to antagonism by spermine or by increasing ionic strength of the medium; (c) phagocytin can be extracted from disrupted granulocytes with dilute citric acid whereas effective extraction of histone requires stronger mineral acid or strong salt solution; (d) phagocytin is limited in distribution to polymorphonuclear leucocytes while histone is demonstrable in many tissues. A new technique has been devised which permits extraction of phagocytin essentially free of lysozyme and histones. Phagocytin thus prepared kills certain Gram-positive bacteria as well as Gram-negative bacilli under appropriate in vitro test conditions. Among susceptible Gram-positive microbes are Group A streptococci and staphylococci. Phagocytin is demonstrable in citric acid extracts of granulocytes obtained from rabbit, man, horse, and guinea pig, the only species thus far investigated. Circulating blood leucocytes as well as exudate cells contain this bactericidal substance. The lethal effects of phagocytin on bacteria may be influenced, depending on the particular microorganism, by either pH or ionic strength of the medium. The bactericidal action of phagocytin is only slightly reduced following digestion with trypsin, chymotrypsin or papain. The active ingredient is, however, non-dialyzable and apparently precipitated by trichloracetic acid. Data available at present are insufficient to define the chemical nature of phagocytin.

  1. Systematic studies of tannin–formaldehyde aerogels: preparation and properties

    Directory of Open Access Journals (Sweden)

    Gisele Amaral-Labat, Andrzej Szczurek, Vanessa Fierro, Antonio Pizzi and Alain Celzard

    2013-01-01

    Full Text Available Gelation of tannin–formaldehyde (TF solutions was systematically investigated by changing pH and concentration of TF resin in water. In this way we constructed the TF phase diagram, from which chemical hydrogels could be described, and also synthesized thermoreversible tannin-based hydrogels. Conditions of non-gelation were also determined. Hydrogels were dried in supercritical CO2, leading to a broad range of TF aerogels. The latter were investigated for volume shrinkage, total porosity, micro-, meso- and macropore volumes, Brunauer–Emmett–Teller (BET surface area, microscopic texture, mechanical and thermal properties. All these properties are discussed in relation to each other, leading to an accurate and self-consistent description of these bioresource-based highly porous materials. The conditions for obtaining the highest BET surface area or mesopore volume were determined and explained in relation to the preparation conditions. The highest BET surface area, 880 m2 g−1, is remarkably high for organic aerogels derived from a natural resource.

  2. Preparing students for graduate study: an eLearning approach.

    Science.gov (United States)

    Pintz, Christine; Posey, Laurie

    2013-07-01

    This paper describes the development and preliminary evaluation of an eLearning program intended to provide incoming nursing students with the basic knowledge, skills and abilities needed to succeed in graduate-level, online coursework. Using Mayer's principles (2008) for the effective design of multimedia instruction, an open-access, self-directed, online program was developed. The Graduate School Boot Camp includes five online modules focused on learning strategies and time management, academic writing, technology, research, and library skills. To motivate and engage learners, the program integrates a fun, graphical sports theme with audiovisual presentations, examples, demonstrations and practice exercises. Learners begin with a self-assessment based on the Motivated Strategies for Learning Questionnaire or MSLQ (Pintrich et al., 1993). To assess change in knowledge levels before and after completing the program, learners take a pre-test and post-test. Preliminary findings indicate that the students found the information relevant and useful. They enjoyed the self-paced, multimedia format, and liked the option to return to specific content later. This innovative program offers a way to prepare students proactively, and may prove useful in identifying students at risk and connecting them with the appropriate resources to facilitate successful program completion.

  3. A Comparative Study of Leadership Preparation Programs in Gama (Brazil) and the United States

    Science.gov (United States)

    Borges-Gatewood, Mara Rubia Fonseca; McNeal, Larry

    2013-01-01

    The objective of the study was to determine the relationship, if any, between leadership preparation programs types and how well school administrators are prepared to set a widely shared vision, develop a school culture, effectively manage school operations and resources, collaborate with faculty and community members, act with integrity and…

  4. Limited-preparation CT colonography in frail elderly patients: a feasibility study.

    LENUS (Irish Health Repository)

    Keeling, Aoife N

    2010-05-01

    Full colonic preparation can be onerous and may be poorly tolerated in frail elderly patients. The purpose of this study was to prospectively assess the image quality and diagnostic yield of limited-preparation CT colonography (CTC) in elderly patients with suspected colorectal cancer who were deemed medically unfit or unsuitable for colonoscopy.

  5. TOGAF version 9 foundation study guide preparation for the TOGAF 9 Part 1 examination

    CERN Document Server

    Harrison, Rachel

    2009-01-01

    This document is a Study Guide for TOGAF™ 9 Foundation.It gives an overview of every learning objective for the TOGAF 9 Foundation Syllabus and in-depth coverage on preparing and taking the TOGAF 9 Part 1 Examination. It is specifically designed to help individuals prepare for certification.

  6. The Preparation of Teacher Candidates for K-12 Online Learning Environments: A Case Study

    Science.gov (United States)

    Williams, Nicole V.

    2015-01-01

    The purpose of this study was to determine how teacher education programs may better prepare teacher candidates to teach in K-12 online learning environments. The primary research question addressed was: What specific knowledge, skills, and dispositions should teacher education programs include in their curriculum to better prepare teacher…

  7. The Effect of Full Crown Preparation on Normal and Inflamed Pulp Tissue: An Animal Study

    Directory of Open Access Journals (Sweden)

    Mandana Vardkar

    2013-12-01

    Full Text Available Introduction: Full crown preparation may have adverse effects on pulp tissue. In this study, the effect of full-crown preparation on intact versus inflamed pulp tissue was studied. Methods: Fifteen healthy mature cats were randomly selected for this study. The study was performed on four canine teeth of each cat. Cats were anesthetized and then radiographs were taken from the canine teeth. Class V cavities were prepared in cat canine teeth. Soft decayed dentin was placed on the floor of cavities and sealed. After 1 month, all of the samples prepared for crown fabrication. Before crown preparation, an impression was taken in a custom tray. During crown preparation, the remnants of carious dentin were removed and undercuts were sealed by glass-ionomer. After preparation, self-cured acrylic temporary crowns were fabricated in a direct procedure and cemented permanently by glass-ionomer. One week later, teeth of the opposite jaw were prepared in a similar procedure. After 2 months, vital perfusion performed and the pulp tissue was histologically examined. Results: There was no significant difference between 4 groups, regarding to histologic status of the pulp. In healthy lower jaw, inflammation was the most frequent but in the other groups, necrosis was most frequent. Also, there was no significant difference between the upper jaw and the lower jaw groups regarding to the frequency of necrosis and inflammation. Conclusion: There is no significant difference between intact and inflamed groups regarding the frequency of necrosis and inflammation

  8. The Effect of Full Crown Preparation on Normal and Inflamed Pulp Tissue: An Animal Study

    Directory of Open Access Journals (Sweden)

    Maryam Bidar

    2013-01-01

    Full Text Available Introduction: Full crown preparation may have adverse effects on pulp tissue. In this study, the effect of full-crown preparation on intact versus inflamed pulp tissue was studied. Methods: Fifteen healthy mature cats were randomly selected for this study. The study was performed on four canine teeth of each cat. Cats were anesthetized and then radiographs were taken from the canine teeth. Class V cavities were prepared in cat canine teeth. Soft decayed dentin was placed on the floor of cavities and sealed. After 1 month, all of the samples prepared for crown fabrication. Before crown preparation, an impression was taken in a custom tray. During crown preparation, the remnants of carious dentin were removed and undercuts were sealed by glass-ionomer. After preparation, self-cured acrylic temporary crowns were fabricated in a direct procedure and cemented permanently by glass-ionomer. One week later, teeth of the opposite jaw were prepared in a similar procedure. After 2 months, vital perfusion performed and the pulp tissue was histologically examined. Results: There was no significant difference between 4 groups, regarding to histologic status of the pulp. In healthy lower jaw, inflammation was the most frequent but in the other groups, necrosis was most frequent. Also, there was no significant difference between the upper jaw and the lower jaw groups regarding to the frequency of necrosis and inflammation. Conclusion: There is no significant difference between intact and inflamed groups regarding the frequency of necrosis and inflammation

  9. Microfinance and poverty reduction: evidence from a village study in Bangladesh.

    Science.gov (United States)

    Nawaz, Shah

    2010-01-01

    To evaluate the competing claims on the impact of microfinance programs on multidimensional poverty, a village study in Bangladesh was conducted where three microfinance programs had been operating for more than five years. The study found that microfinance has resulted in a moderate reduction in the poverty of borrowers, as measured by a variety of socio-economic indicators, but has not reached many of the poorest in the village. To make microfinance a more effective means of poverty reduction other services such as skills training, technological support, education and health related strategies should be included with microfinance.

  10. The reduction process of phytic acid silver ion system: A pulse radiolysis study

    Science.gov (United States)

    Joshi, Ravi; Mukherjee, Tulsi

    2007-05-01

    Reduction of silver ion in a silver-phytic acid (1:1 ratio) system has been studied using pulse radiolysis technique. Time-resolved transformation of the intermediates, Ag +→Ag 0→Ag 2+→Ag 32+, has been clearly observed in the reduction of silver-phytic acid (1:1) system. The effect of phytic acid on the formation and decay of initial silver clusters has been also studied. The surface plasmon absorption band of stable silver nanoparticle (410 nm) and dynamic light scattering technique has been used to characterize the nanoparticles and measure the average size ( Rav=100 nm).

  11. Studies on the reduction of birnessite thin layers: Influence of medium

    Energy Technology Data Exchange (ETDEWEB)

    Ndjeri, Marthe [CNRS - Universite d' Evry - CEA, ' Laboratoire Analyse et Modelisation pour la Biologie et l' Environnement' , UMR 8587, Universite d' Evry Val d' Essonne, Boulevard Francois Mitterrand, 91025 Evry (France); Peulon, Sophie, E-mail: sophie.peulon@univ-evry.fr [CNRS - Universite d' Evry - CEA, ' Laboratoire Analyse et Modelisation pour la Biologie et l' Environnement' , UMR 8587, Universite d' Evry Val d' Essonne, Boulevard Francois Mitterrand, 91025 Evry (France); Bach, Stephane, E-mail: stephane.bach@univ-evry.fr [Universite d' Evry Val d' Essonne, Bd F. Mitterrand, Departement Chimie, 91025 Evry, Cedex (France); Institut de Chimie et des Materiaux Paris Est, ICMPE/GESMAT, UMR 7182 CNRS (France); Chausse, Annie [CNRS - Universite d' Evry - CEA, ' Laboratoire Analyse et Modelisation pour la Biologie et l' Environnement' , UMR 8587, Universite d' Evry Val d' Essonne, Boulevard Francois Mitterrand, 91025 Evry (France)

    2011-10-01

    Highlights: > Determination of compounds during reduction of birnessite layer. > Importance of Mn(II) ions in solution on the nature of resulting compounds. > Proposition of reduction mechanisms of birnessite thin films. > Interests of XRD characterisation coupled to electrochemistry. - Abstract: This paper describes studies on the reduction of birnessite thin layers electrodeposited onto a cheap transparent semiconductor substrate, tin dioxide (SnO{sub 2}), in neutral sulphate solutions. A coupled approach based on electrochemical measurements (cyclic voltammetry and chronoamperometry) and X-ray diffraction (XRD) characterisation allowed us to give information about reduction mechanism of birnessite in presence or absence of Mn(II) in solution. In absence of Mn(II), birnessite is reduced only at low potential (E = -0.6 V) into {beta}-MnOOH (feitkneichtite), if Q{sub reduction} is lower than Q{sub synthesis}, and in amorphous Mn(II) compound, if Q{sub reduction} is equal to Q{sub synthesis}. In presence of Mn(II) in solution, hausmannite (Mn{sub 3}O{sub 4}) was detected, and even at high potentials (E = 0.15 V). These results signify that a complex between Mn(III), coming from the reduction of Mn(IV) species, and Mn(II) present in solution, can be formed near the surface and leads to the formation of Mn{sub 3}O{sub 4}, a very resistive compound. These results are important for studies devoted to environmental applications, chemical sensors and also for energy storage.

  12. Using Online Case Studies to Enhance Teacher Preparation

    Science.gov (United States)

    Richman, Laila

    2015-01-01

    The purpose of this study was to assess the impact interactive, online case studies have on learning for preservice teachers. More specifically, it evaluated whether the use of online case studies in instruction could enhance the level of knowledge the preservice teacher gained from the content material. This study utilized a nonequivalent group,…

  13. Effect of Self-myofascial Release on Reduction of Physical Stress: A Pilot Study.

    Science.gov (United States)

    Kim, Kanghoon; Park, Sunghyun; Goo, Bong-Oh; Choi, Seok-Cheol

    2014-11-01

    [Purpose] This study aims to examined the effect of the self-myofascial release induced with a foam roller on the reduction of stress by measuring the serum concentration of cortisol. [Subjects and Methods] The subjects of this study were healthy females in their 20s. They were divided into the experimental and control groups. Both groups, each consisting of 12 subjects, were directed to walk for 30 minutes on a treadmill. The control group rested for 30 minutes of rest by lying down, whereas the experimental group was performed a 30 minutes of self-myofascial release program. [Results] Statistically significant levels of cortisol concentration reduction were observed in both the experimental group, which used the foam roller, and the control group. There was no statistically significant difference between the two groups. [Conclusion] The Self-myofascial release induced with a foam roller did not affect the reduction of stress.

  14. Preparation of Pt Ru/C + rare earths by the method of reduction by alcohol for the electro-oxidation of ethanol; Preparacao de eletrocatalisadores PtRu/C + terras raras pelo metodo da reducao por alcool para a eletro-oxidacao do etanol

    Energy Technology Data Exchange (ETDEWEB)

    Tusi, M.M.; Rodrigues, R.M.S.; Spinace, E.V.; Oliveira Neto, A., E-mail: aolivei@ipen.b, E-mail: espinace@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2010-07-01

    PtRu/C electrocatalyst was prepared in a single step, while that PtRu/85%C-15%Ce, PtRu/85%C-15%La, PtRu/85%C-15%Nd and PtRu/85%C-15%Er electrocatalyst were prepared in a two step. In the first step a Carbon Vulcan XC72 + rare earth supports were prepared. In the second step PtRu electrocatalyst were prepared by an alcohol-reduction process using ethylene glycol as solvent and reducing agent and supported on Vulcan XC72 + earth rare. The obtained electrocatalysts were characterized by EDAX, XRD and chronoamperometry. The electro-oxidation of ethanol was studied by chronoamperometry at room temperature. PtRu/85%C- 15%Ce electrocatalyst showed a significant increase of performance for ethanol oxidation compared to PtRu/C electrocatalyst. (author)

  15. Open reduction and intramedullary stabilisation of subtrochanteric femur fractures: A retrospective study of 56 cases.

    Science.gov (United States)

    Beingessner, Daphne M; Scolaro, John A; Orec, Robert J; Nork, Sean E; Barei, David P

    2013-12-01

    Subtrochanteric femur fractures commonly present with predictable displacement because of the deforming muscle forces acting upon the proximal femur. For this reason, successful closed reduction and femoral nailing can be a technically demanding procedure. Open reduction prior to nail placement has been advocated to improve and maintain anatomic fracture alignment. The purpose of this study was to evaluate the results of patients with closed subtrochanteric femur fractures treated with open reduction and a reamed antegrade statically locked intramedullary nail. An initial query of our database identified 154 patients who had sustained a subtrochanteric femur fracture over the defined study period. Ninety-six patients had adequate radiographic and clinical follow-up. Fifty-six (58%) patients were treated with open reduction and nail placement. There were no wound complications or infections and all patients went on to successful osseous union. There was no loss of reduction and a final coronal and sagittal plane deformity of subtrochanteric femur fractures followed by intramedullary nailing leads to high union rates with rare complications.

  16. 电化学还原制备铂-氢钨青铜阳极%Preparation of Platinum-hydrogen Tungsten Bronze Anodes by Electrochemical Reduction

    Institute of Scientific and Technical Information of China (English)

    杨勇; 赵文文; 施庆乐; 张华

    2011-01-01

    Anodes of proton exchange membrane fuel cell with the platinum-hydrogen tungsten bronze (H^Woj) as the composite catalysts were prepared by electrochemical reduction on carbon cloth. The catalysts were characterized by XRD, SEM, EIS and single-cell polarization tests. The results showed that the order of electrochemical reduction had a major impact on the morphology and dispersion of the catalysts. The composite catalyst of H^Woj/Pt exhibited synergistic catalytic effect and increased the catalytic activity for hydrogen"oxidation. The H^Woj/Pt catalyst showed the highest catalytic activity for hydrogen oxidation, while the Pt-HIWO3 catalyst showed the lowest catalytic activity. Because of the coexistence of two electrolytes, less hydrogen tungsten bronze catalyst was deposited on the electrode and platinum agglomerated obviously on the Pt-HIWO3 electrodes, leading to a decrease of the catalytic activity.%用电化学还原法在炭布上电沉积铂-氢钨青铜复合催化剂作为质子交换膜燃料电池(PEMFC)阳极.利用X射线衍射、扫描电子显微镜、单电池极化性能测试以及电化学阻抗谱(EIS)法研究了催化剂的组成、分散性及其对氢氧化的电催化性能.实验结果表明,阴极还原顺序对催化剂的形貌及分散有较大的影响.采用分步还原法制备的HxWO3/Pt电极(先沉积铂,后沉积氢钨青铜)对氢氧化具有较高的催化活性,氢钨青铜与.铂形成协同催化效应,提高了铂对氢氧化的催化活性.而共沉积制备的Pt-HxWO3催化剂的电催化活性较差,这是因为共沉积过程中,由于受到2种电解液共存的影响,电极催化层中没有或较少得到氢钨青铜,且铂催化剂出现明显的团聚现象.

  17. SELECTIVE REDUCTION OF NOX IN OXYGEN RICH ENVIRONMENTS WITH PLASMA-ASSISTED CATALYSIS: CATALYST DEVELOPMENT AND MECHANISTIC STUDIES

    Energy Technology Data Exchange (ETDEWEB)

    Peden, C; Barlow, S; Hoard, J; Kwak, J; *Balmer-Millar, M; *Panov, A; Schmieg, S; Szanyi, J; Tonkyn, R

    2003-08-24

    The control of NOx (NO and NO2) emissions from so-called ''lean-burn'' vehicle engines remains a challenge. In recent years, there have been a number of reports that show that a plasma device combined with a catalyst can reduce as high as 90% or more of NOx in simulated diesel and other ''lean-burn'' exhaust. In the case of propylene containing simulated diesel exhaust, the beneficial role of a plasma treatment is now thought to be due to oxidation of NO to NO2, and the formation of partially oxidized hydrocarbons that are more active for the catalytic reduction of NO2 than propylene. Thus, the overall system can be most usefully described as hydrocarbon selective catalytic reduction (SCR) enhanced by 'reforming' the exhaust with a non-thermal plasma (NTP) device. For plasma-enhanced catalysis, both zeolite- and alumina-based materials have shown high activity, albeit in somewhat different temperature ranges, when preceded by an NTP reactor. This paper will briefly describe our research efforts aimed at optimizing the catalyst materials for NTP-catalysis devices based, in part, on our continuing studies of the NTP- and catalytic-reaction mechanisms. Various alkali- and alkaline earth-cation-exchanged Y zeolites have been prepared, their material properties characterized, and they have been tested as catalytic materials for NOx reduction in laboratory NTP-catalysis reactors. Interestingly, NO2 formed in the plasma and not subsequently removed over these catalysts, will back-convert to NO, albeit to varying extents depending upon the nature of the cation. Besides this comparative reactivity, we will also discuss selected synthesis strategies for enhancing the performance of these zeolite-based catalyst materials. A particularly important result from our mechanistic studies is the observation that aldehydes, formed during the plasma treatment of simulated diesel exhaust, are the important species for the reduction of

  18. Studies on Novel Polymer Materials Prepared through Intermacromolecular Complexation

    Institute of Scientific and Technical Information of China (English)

    WANG Qi; GAO Jun; DAN Yi; CHEN Zhe

    2004-01-01

    The basic feature of polymers is their multi-order structure. Structure change at each level offers a possibility tomodify polymer properties and to develop new polymer materials. Therefore,novel polymer materials can be developed by tailoring their chain structure through chemical bonding among atoms, i.e., via the traditional molecular chemistry methods, e.g., polymerization of new monomer, controlling chain length (molecular weight and molecular weight distribution) and stereoregularity, copolymerization of different kinds of monomers, controlling sequence distribution,block of graft length of copolymer, etc., which have been the focus of polymer chemistry for several decades, as well as by tailoring specific supramolecular architecture using molecules as building block through intermolecular interactions, i.e., via supramolecular science methods, e.g., molecular self-assembly, intermacromolecular complexation, etc., which is a modern and fast-developing academic research field.This paper reports novel polymer materials prepared through intermacromolecular complexation,e.g., a new polymer solid electrolyte poly(metyl methacrylate-methacrylic acid)[P(MMA-MAA)]/poly(ethylene oxide) (PEO)/A2-LiClO4 developed by intermacromolecular complexation through hydrogen bonding, which has enhanced ambient ionic conductivity and fairly good mechanical and film-forming properties, a new polymer microcomposite poly(acrylonitrile-acrylamide-acrylic acid) [P(AN-AM-AA)]/poly(vinyl alcohol) (PVA) reinforced by the twin molecular chain microfibrils formed through intermacromolecular complexation of P(AN-AM-AA) with PVA through hydrogen bonding, which exhibits much better mechanical properties than its constituents and could be used to manufacture PVA based complexed fibers with higher modulus and better dyeability, a new polymer flooding agent poly(acrylamide-acrylic acid)[P(AM-AA)]/poly(acrylamide- dimethyldiallylammonium chloride) [P(AM-DMDAAC)] developed by intermacromolecular

  19. Tin-graphite materials prepared by reduction of SnCl{sub 4} in organic medium: Synthesis, characterization and electrochemical lithiation

    Energy Technology Data Exchange (ETDEWEB)

    Balan, L.; Billaud, D. [LCSM, UMR CNRS 7555, UHP Nancy I, BP 239, 54506 Vandoeuvre-les-Nancy Cedex (France); Schneider, R. [SOR, UMR CNRS 7565, UHP Nancy I, BP 239, 54506 Vandoeuvre-les-Nancy Cedex (France); Willmann, P. [CNES, 18 Avenue E. Belin, 31055 Toulouse Cedex (France)

    2006-10-20

    Tin-graphite materials were prepared by chemical reduction of SnCl{sub 4} by t-BuONa-activated NaH. TEM imaging showed that the crude material is composed of an amorphous organic matrix containing tin present either as nanosized particles deposited on the graphite surface or as free aggregates. Subsequent washings with ethanol and water allow removal of side products as well as most part of the organic matrix. Electrochemical insertion of lithium occurred in graphite and in tin. The initial reversible massic capacity of 630mAhg{sup -1} decayed to a stable value of 415mAhg{sup -1} after 12 cycles. This capacity value was lower than the expected maximum one of 650mAhg{sup -1} corresponding to a Sn/12C molar composition and assuming the formation of LiC{sub 6} and Li{sub 22}Sn{sub 5}. Even if this massic capacity is not much improved by comparison with that of graphite, it must be pointed out that the volume capacity of this graphite/Sn material is much larger (2137mAhcm{sup -3}) than that corresponding to graphite (837mAhcm{sup -3}). It was hypothesized that the part of tin bound to graphite could be responsible for the stable reversible capacity. To the contrary, graphite unsupported tin aggregates would contribute to the observed gradual decline in the storage capacity. Therefore, the improvement in cycleability, compared to that of massive metals, could be attributed both to the nanoscale dimension of the metal particles and to interactions between graphite and metal the nature of which remaining to be precised. (author)

  20. Carbon paper supported Pt/Au catalysts prepared via Cu underpotential deposition-redox replacement and investigation of their electrocatalytic activity for methanol oxidation and oxygen reduction reactions

    Energy Technology Data Exchange (ETDEWEB)

    Khosravi, Mohsen; Amini, Mohammad K. [Chemistry Department, University of Isfahan, Isfahan 81744-73441 (Iran)

    2010-10-15

    Through a simple and rapid method, carbon papers (CPs) were coated with Au and the resulting Au/CP substrates were used for the preparation of Pt/Au/CP by Cu underpotential deposition (Cu UPD) and redox replacement technique. A series of Pt{sub n}/Au/CP catalysts (where n = number of UPD-redox replacement cycles) were synthesized and their electrochemical properties for methanol oxidation reaction (MOR), and oxygen reduction reaction (ORR) were investigated by electrochemical measurements. The Pt{sub n}/Au/CP electrodes show higher electrocatalytic activity and enhanced poison tolerance for the MOR as compared to a commercial Pt/C on CP (Pt/C/CP). The highest mass specific activity and Pt utilization efficiency for MOR was observed on Pt{sub 1}/Au/CP with a thickness close to a monatomic Pt layer. Chronoamperometric tests in methanol solution revealed that Pt{sub n}/Au/CPs have much higher CO tolerance compared to Pt/C/CP. Among the Pt{sub n}/Au/CPs, CO tolerance decreases with increasing the amount of deposited Pt, indicating that the exposed Au atoms in close proximity to Pt plays a positive role against CO poisoning. Compared with the Pt/C/CP, all the Pt{sub n}/Au/CP electrodes show more positive onset potentials and lower overpotentials for ORR. For instance, the onset potential of ORR is 150 mV more positive and the overpotential is {proportional_to}140 mV lower on Pt{sub 4}/Au/CP with respect to Pt/C/CP. (author)

  1. Reduction of Salmonella on chicken breast fillets stored under aerobic or modified atmosphere packaging by the application of lytic bacteriophage preparation SalmoFreshTM.

    Science.gov (United States)

    Sukumaran, Anuraj T; Nannapaneni, Rama; Kiess, Aaron; Sharma, Chander Shekhar

    2016-03-01

    The present study evaluated the efficacy of recently approved Salmonella lytic bacteriophage preparation (SalmoFresh™) in reducing Salmonella on chicken breast fillets, as a surface and dip application. The effectiveness of phage in combination with modified atmosphere packaging (MAP) and the ability of phage preparation in reducing Salmonella on chicken breast fillets at room temperature was also evaluated. Chicken breast fillets inoculated with a cocktail of Salmonella Typhimurium, S. Heidelberg, and S. Enteritidis were treated with bacteriophage (10(9) PFU/mL) as either a dip or surface treatment. The dip-treated samples were stored at 4°C aerobically and the surface-treated samples were stored under aerobic and MAP conditions (95% CO2/5% O2) at 4°C for 7 d. Immersion of Salmonella-inoculated chicken breast fillets in bacteriophage solution reduced Salmonella (P chicken breast fillets when the samples were surface treated with phage and stored under MAP conditions. The Salmonella counts were reduced by 1.2, 1.1, and 1.2 log CFU/g on d 0, 1, and 7 of storage, respectively. Bacteriophage surface application on chicken breast fillets stored at room temperature reduced the Salmonella counts by 0.8, 0.9, and 0.4 log CFU/g after 0, 4, and 8 h, respectively, compared to the untreated positive control. These findings indicate that lytic phage preparation was effective in reducing Salmonella on chicken breast fillets stored under aerobic and modified atmosphere conditions.

  2. Intraarticular lidocaine versus intravenous analgesic for reduction of acute anterior shoulder dislocations. A prospective randomized study.

    Science.gov (United States)

    Matthews, D E; Roberts, T

    1995-01-01

    We performed a prospective, randomized study to evaluate the use of injected lidocaine as an anesthetic for closed reduction of acute anterior shoulder dislocations. Thirty consecutive patients who presented at the emergency department with acute anterior shoulder dislocations were randomly placed in one of two groups. One group received an intraarticular injection of 20 ml of 1% lidocaine and the other group, intravenous injections of morphine sulfate and midazolam. The groups were compared regarding time of reduction maneuver, difficulty of reduction, subjective pain, complications, and total time spent in the emergency department. The lidocaine provided adequate anesthesia and secondary relief of muscle spasm in 15 of 15 (100%) patients. When compared with the intravenous sedation group, the lidocaine group showed no statistically significant difference in time for reduction maneuver, difficulty of reduction, or subjective pain. The lidocaine group had no complications and had a statistically significant shorter emergency department visit when compared with the intravenous sedation group (mean, 78 minutes versus 186 minutes; P = 0.004). Lidocaine provides excellent anesthesia for patients with uncomplicated anterior shoulder dislocations and can be very beneficial when sedation is contraindicated. Lidocaine injections also proved to be cost effective in our institution, reducing total costs by as much as 62%.

  3. Klebsiella pneumoniae Planktonic and Biofilm Reduction by Different Plant Extracts: In Vitro Study

    Science.gov (United States)

    da Rocha Santos, Carlos Eduardo; Camargo Reis Mello, Daphne; Nishiama Theodoro, Lígia; De Oliveira, Felipe Eduardo; Back Brito, Graziella N.; Campos Junqueira, Juliana; Cardoso Jorge, Antonio Olavo; Dias de Oliveira, Luciane

    2016-01-01

    This study evaluated the action of Pfaffia paniculata K., Juglans regia L., and Rosmarius officinalis L. extracts against planktonic form and biofilm of Klebsiella pneumoniae (ATCC 4352). Minimum inhibitory concentration (MIC) and minimum microbicidal concentration (MMC) values were determined for each extract by microdilution broth method, according to Clinical and Laboratory Standards Institute. Next, antimicrobial activity of the extracts on biofilm was analyzed. For this, standardized suspension at 107 UFC/mL of K. pneumoniae was distributed into 96-well microplates (n = 10) and after 48 h at 37°C and biofilm was subjected to treatment for 5 min with the extracts at a concentration of 200 mg/mL. ANOVA and Tukey tests (5%) were used to verify statistical significant reduction (p < 0.05) of planktonic form and biofilm. P paniculata K., R. officinalis L., and J. regia L. showed reductions in biomass of 55.6, 58.1, and 18.65% and cell viability reduction of 72.4, 65.1, and 31.5%, respectively. The reduction obtained with P. paniculata and R. officinalis extracts was similar to the reduction obtained with chlorhexidine digluconate 2%. In conclusion, all extracts have microbicidal action on the planktonic form but only P. paniculata K. and R. officinalis L. were effective against biofilm. PMID:28004034

  4. Toxics Use Reduction in the Home: Lessons Learned from Household Exposure Studies.

    Science.gov (United States)

    Dunagan, Sarah C; Dodson, Robin E; Rudel, Ruthann A; Brody, Julia G

    2011-03-01

    Workers and fence-line communities have been the first to benefit from the substantial reductions in toxic chemical use and byproducts in industrial production resulting from the Massachusetts Toxics Use Reduction Act (TURA). As TURA motivates reformulation of products as well as retooling of production processes, benefits could extend more broadly to large-scale reductions in everyday exposures for the general population. Household exposure studies, including those conducted by Silent Spring Institute, show that people are exposed to complex mixtures of indoor toxics from building materials and a myriad of consumer products. Pollutants in homes are likely to have multiple health effects because many are classified as endocrine disrupting compounds (EDCs), with the ability to interfere with the body's hormone system. Product-related EDCs measured in homes include phthalates, halogenated flame retardants, and alkylphenols. Silent Spring Institute's chemical analysis of personal care and cleaning products confirms many are potential sources of EDCs, highlighting the need for a more comprehensive toxics use reduction (TUR) approach to reduce those exposures. Toxics use reduction targeted at EDCs in consumer products has the potential to substantially reduce occupational and residential exposures. The lessons that have emerged from household exposure research can inform improved chemicals management policies at the state and national levels, leading to safer products and widespread health and environmental benefits.

  5. Pilot study on bromate reduction in ozonation of water with low carbonate alkalinities by carbon dioxide

    Institute of Scientific and Technical Information of China (English)

    Ji Li; Li Zou; Lulu Guo; Jialin Ji

    2011-01-01

    A pilot study was carried out to explore the application of carbon dioxide for pH depression in a bubble column and its ability to inhibit bromate formation for water with a low alkalinity.Results showed that in the absence of ammonia,CO2 was capable of reducing bromate 38.0%-65.4% with one-unit pH depression.CO2 caused a slightly lower bromate reduction (4.2%) than did H2SO4 when the pH was depressed to 7.4,and a more a pronounced lower reduction (8.8%) when the pH was depressed to 6.9.In the presence of 0.20mg/L-N ammonia,bromate was largely inhibited with 73.9% reduction.When the pH was depressed to 7.4,CO2 and H2SO4 showed an 11.3% and 23.5% bromate reduction respectively,demonstrating that the joint use of CO2 and ammonia might be a plausible strategy of blocking all three bromate formation pathways.CO2 could be applied through the aeration diffuser together with ozone gas,resulting in a similar bromate reduction compared with the premixing method through Venturi mixer.

  6. Klebsiella pneumoniae Planktonic and Biofilm Reduction by Different Plant Extracts: In Vitro Study

    Directory of Open Access Journals (Sweden)

    Lucas De Paula Ramos

    2016-01-01

    Full Text Available This study evaluated the action of Pfaffia paniculata K., Juglans regia L., and Rosmarius officinalis L. extracts against planktonic form and biofilm of Klebsiella pneumoniae (ATCC 4352. Minimum inhibitory concentration (MIC and minimum microbicidal concentration (MMC values were determined for each extract by microdilution broth method, according to Clinical and Laboratory Standards Institute. Next, antimicrobial activity of the extracts on biofilm was analyzed. For this, standardized suspension at 107 UFC/mL of K. pneumoniae was distributed into 96-well microplates (n=10 and after 48 h at 37°C and biofilm was subjected to treatment for 5 min with the extracts at a concentration of 200 mg/mL. ANOVA and Tukey tests (5% were used to verify statistical significant reduction (p<0.05 of planktonic form and biofilm. P paniculata K., R. officinalis L., and J. regia L. showed reductions in biomass of 55.6, 58.1, and 18.65% and cell viability reduction of 72.4, 65.1, and 31.5%, respectively. The reduction obtained with P. paniculata and R. officinalis extracts was similar to the reduction obtained with chlorhexidine digluconate 2%. In conclusion, all extracts have microbicidal action on the planktonic form but only P. paniculata K. and R. officinalis L. were effective against biofilm.

  7. A Study of Shrinkage Stress Reduction and Mechanical Properties of Nanogel-Modified Resin Systems.

    Science.gov (United States)

    Liu, Jiancheng; Howard, Gregory D; Lewis, Steven H; Barros, Matthew D; Stansbury, Jeffrey W

    2012-11-01

    A series of nanogel compositions were prepared from urethane dimethacrylate (UDMA) and isobornyl methacrylate (IBMA) in the presence of a thiol chain transfer agent. The linear oligomer of IBMA was synthesized by a similar solution polymerization technique. The nanogels were prepared with different crosslinker concentrations to achieve varied branching densities and molecular weights. The prepolymers were dispersed in triethylene glycol dimethacrylate at loading levels ranging from 10 wt% to 50 wt%. Photopolymerization reaction kinetics of all prepolymer modified systems were enhanced relative to the nanogel-free control during early stage polymerization while limiting conversion was similar for most samples. Volumetric polymerization shrinkage was reduced proportionally with the prepolymer content while the corresponding decrease in polymerization stress was potentially greater than an additive linear behavior. Flexural strength for inert linear polymer-modified systems decreased significantly with the increase in the prepolymer content; however, with an increase in the crosslinker concentration within the nanogel additives, and an increase in the concentration of residual pendant reactive sites, flexural strength was maintained or improved regardless of the nanogel loading level. This demonstrates that covalent attachment rather than just physical entanglement with the polymer matrix is important for effective polymer mechanical reinforcement by nanogel additives. Reactive nanogel additives can be considered as a practical, generic means to achieve substantial reductions in polymerization shrinkage and shrinkage stress in common polymers.

  8. Mössbauer study of carbon coated iron magnetic nanoparticles produced by simultaneous reduction/pyrolysis

    Science.gov (United States)

    Mendonça, Fernanda G.; Ardisson, José D.; Rosmaninho, Marcelo G.; Lago, Rochel M.; Tristão, Juliana C.

    2011-11-01

    Magnetic iron nanoparticles immersed in a carbon matrix were produced by a combined process of controlled dispersion of Fe3 + ions in sucrose, thermal decomposition with simultaneous reduction of iron cores and the formation of the porous carbonaceous matrix. The materials were prepared with iron contents of 1, 4 and 8 in %wt in sucrose and heated at 400, 600 and 800°. The samples were analyzed by XRD, Mössbauer spectroscopy, magnetization measurements, TG, SEM and TEM. The materials prepared at 400° are composed essentially of Fe3O4 particles and carbon, while treatments at higher temperatures, e.g. 600 and 800° produced as main phases Fe0 and Fe3C. The Mössbauer spectra of samples heated at 400° showed two sextets characteristic of a magnetite phase and other contributions compatible with Fe3 + and Fe2 + phases in a carbonaceous matrix. Samples treated at temperatures above 600° showed the presence of metallic iron with concentrations between 16-43%. The samples heated at 800° produced higher amounts of Fe3C (between 20% and 58%). SEM showed for the iron 8% sample treated at 600-800°C particle sizes smaller than 50 nm. Due to the presence of Fe0 particles in the carbonaceous porous matrix the materials have great potential for application as magnetic adsorbents.

  9. Reduction of Guanosyl Radical by Cysteine and Cysteine-Glycine Studied by Time-Resolved CIDNP

    NARCIS (Netherlands)

    Morozova, O.B.; Kaptein, R.; Yurkovskaya, A.V.

    2012-01-01

    As a model for chemical DNA repair, reduction of guanosyl radicals in the reaction with cysteine or the dipeptide cysteine-glycine has been studied by time-resolved chemically induced dynamic nuclear polarization (CIDNP). Radicals were generated photochemically by pulsed laser irradiation of a solut

  10. Inquiry-Based Stress Reduction Meditation Technique for Teacher Burnout: A Qualitative Study

    Science.gov (United States)

    Schnaider-Levi, Lia; Mitnik, Inbal; Zafrani, Keren; Goldman, Zehavit; Lev-Ari, Shahar

    2017-01-01

    An inquiry-based intervention has been found to have a positive effect on burnout and mental well-being parameters among teachers. The aim of the current study was to qualitatively evaluate the effect of the inquiry-based stress reduction (IBSR) meditation technique on the participants. Semi-structured interviews were conducted before and after…

  11. Experimental Study on Physical Mechanism of Drag Reduction of Hydrophobic Materials in Laminar Flow

    Institute of Scientific and Technical Information of China (English)

    YU Yong-Sheng; WEI Qin-Ding

    2006-01-01

    We experimentally study the physical mechanism of the drag reduction of hydrophobic materials in the macroscopic scale. The experiment includes the drag and velocity measurements of laminar boundary layer Sow over flat plates, and the observation of air bubbles on the surfaces. The plate surfaces have different wetting and roughness properties. In the drag measurements, the plates with bubbles on the surfaces lead to drag reduction, but not for those without bubbles. Velocity measurement confirms that the flow is laminar and gives apparent fluid slip on the plate wall with bubbles. In observation, air bubbles in macroscopic size emerge and enlarge on hydrophobic surfaces but not on hydrophilic surfaces. Therefore, the drag reduction of hydrophobic materials is explained by the generation of air bubbles of macroscopic size that cause the apparent velocity slip.

  12. Designed plasmonic nanocatalysts for the reduction of eosin Y: absorption and fluorescence study

    Science.gov (United States)

    Komalam, Abha; Muraleegharan, Lekha Girija; Subburaj, Suganthi; Suseela, Suji; Babu, Aswathy; George, Sony

    2012-10-01

    In this work, we report a one-step green synthesis of gold nanoparticles (AuNPs) by microwave irradiation using nontoxic and biodegradable polysaccharide chitosan as a reducing and stabilizing agent. The interaction between gold nanoparticles with the amine group of chitosan was confirmed by Fourier transform infrared spectroscopy analysis, and the stability of the nanoparticle is ascertained by zeta potential measurements. Transmission electron microscopy photograph and dynamic light scattering measurements confirmed the average size of gold nanoparticles as 25 nm. The ability of the synthesised gold nanoparticles as a catalyst for the reduction of eosin dye in the presence of NaBH4 was monitored by means of spectrofluorometry and spectrophotometry. It is found that the NaBH4-induced reduction of eosin is enhanced in the presence of AuNPs even without a catalyst. Time-resolved fluorescence decay studies also confirmed the reduction of eosin in the presence of AuNPs.

  13. Electrochemical Studies on Cathodic Reduction of Titanium Dioxide in Molten Calcium Chloride

    Science.gov (United States)

    Mohanty, Jayashree; Mishra, Krushna Gopal; Paramguru, Raja Kishore; Mishra, Barada Kanta

    2012-06-01

    The polarization studies have been performed on the electrochemical reduction of TiO2 in a molten CaCl2 bath at 950°C. The cathodic and anodic plots have been drawn by taking TiO2 pellet as cathode and graphite rod as anode, respectively. The cathodic and anodic over-potentials at various cell voltages have been measured. Prolonged electrolysis has been carried out at a cell voltage of 3 V and the resultant products have been analyzed by X-ray Diffraction to find out the reaction pathway through which TiO2 is reduced to titanium. The results indicate that the electrochemical reduction of TiO2 to titanium proceeds through a multi-step reduction process.

  14. Temperature Programmed Reduction Studies on CeO2-Containing Catalysts

    Institute of Scientific and Technical Information of China (English)

    Noriyoshi Kakuta; Harunobu Ohkita; Takanori Mizushima

    2004-01-01

    Temperature programmed reduction (TPR) study was carried out for CeO2/Al2O3 and CeO2/ZrO2 catalysts to evaluate oxygen storage property induced by a facile redox cycling of Ce ion. The CeO2/ZrO2 catalyst possesses excellent oxygen storage activity at 373 K after reduction above 1173 K although the oxygen storage of CeO2/Al2O3 catalyst after reduction above 1173 K is poor because of the formation of CeAlO3. Consequently, the oxygen storage on the CeO2/ZrO2 catalyst smoothly occurs from low temperatures when the catalyst is reduced even at high temperatures.

  15. QSAR and SAR studies on the reduction of some aromatic nitro compounds by xanthine oxidase.

    Science.gov (United States)

    Thakur, Mamta; Thakur, Abhilash; Balasubramanian, Krishnan

    2006-01-01

    This work describes QSAR and SAR studies on the reduction of 27 aromatic nitro compounds by xanthine oxidase using both distance-based topological indices and quantum molecular descriptors along with indicator parameters. The application of a multiple linear regression analysis indicated that a combination of distance-based topological indices with the ad hoc molecular descriptors and the indicator parameters yielded a statistically significant model for the activity, log K (the reduction of aromatic nitro compounds by xanthine oxidase). The final selection of a potential aromatic nitro compound for the reduction by xanthine oxidase is made by quantum molecular modeling. We have found that, among the various parameters, the quantum Mulliken charge parameters on the fourth atom or para position relative to the nitro group correlated best with the activity.

  16. Study of greenhouse gases reduction alternatives for the exploitation of non conventional oil sands in Canada

    Energy Technology Data Exchange (ETDEWEB)

    Bouchonneau, Deborah [Institut Francais du Petrole (IFP), Paris (France)

    2008-07-01

    High energy prices and greenhouse gases reduction represent the main challenges the current worldwide energetic situation has to face. As a consequence, paradox strategies can be highlighted: oil prices are sufficiently high to exploit non conventional oil resources, like extra heavy oils and oil sands. But the production of these resources emits larger GHG than the conventional oil path and implies other major environmental issues (water management, risks of soil pollution, destruction of the boreal forest), incompatible with the rules validated by the protocol of Kyoto. At the light of the new greenhouse gases reduction regulation framework announced by the Canadian Federal government, this work focuses on the study of greenhouse gases reduction alternatives applied to the non conventional oil sands exploitation in Canada. (author)

  17. Study on Simultaneous Catalytic Reduction of Sulfur Dioxide and Nitric Oxide on Rare Earth Mixed Compounds

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    CeO2/γ-Al2O3, La2O3/γ-Al2O3, CeO2-La2O3/γ-Al2O3 and CeO2-La2O3, which were prepared by impregnating in certain ratio, were used as the catalysts for the reduction of SO2 and NO by CO. Separate and simultaneous removal of SO2 and NO over La2O3/γ-Al2O3, CeO2/γ-Al2O3, CeO2-La2O3/γ-Al2O3 were investigated. The phase characteristics of catalysts were also analyzed by X-ray diffraction. The result shows that the conversions of SO2 and NO are above 98% over CeO2/γ-Al2O3 and CeO2-La2O3/γ-Al2O3. After SO2 is added in the NO-CO-N2 system (NO∶SO2=1∶2~1∶3), the conversions of SO2 and NO are both above 98%. Furthermore, it is found that CeO2-La2O3 with various ratios has different activity for the simultaneous reduction of SO2 and NO.

  18. Citizenship Education and the Preparation of Future Teachers: A Study.

    Science.gov (United States)

    Karsten, Sjoerd; Cogan, John J.; Grossman, David L.; Liu, Mei-hui; Pitiyanuwat, Somwung

    2002-01-01

    Report of a study that examines the views of 250 future teachers of social studies regarding significant global trends, required citizenship characteristics, and educational strategies to develop such characteristics. Subjects were from China, Hong Kong, Japan, The Netherlands, Taiwan, Thailand, and the United States. (Contains 4 tables and 41…

  19. Impact of bowel preparation type on the quality of colonoscopy: a multicenter community-based study

    Directory of Open Access Journals (Sweden)

    Daniel Martin

    2016-04-01

    Full Text Available Background: High-quality bowel preparation is crucial for achieving the goals of colonoscopy. However, choosing a bowel preparation in clinical practice can be challenging because of the many formulations. This study aims to assess the impact the type of bowel preparation on the quality of colonoscopy in a community hospital setting. Methods: A retrospective, observational study was conducted utilizing a colonoscopy screening/surveillance database in central Illinois during the period of January 1, 2010, to March 31, 2014. Patients without bowel preparation assessment were excluded from this study. Controlling for the confounders, generalized linear models were used to estimate the adjusted impact [odds ratio (OR] of bowel preparation type on the quality of preparation (excellent, good, fair, and poor, and on the detection of advanced adenoma. The association between the time of withdrawal after insertion and the quality of preparation was also examined using a linear model. Results: A total of 28,368 colonoscopies; half the patients were male, and the average age was 61±9 years. Polyethylene glycol (PEG was used in the majority (70.2% of bowel preparations, followed by sodium sulfate (21.4%, sodium phosphate (2.5%, magnesium sulfate (0.4%, and others. Compared with PEG, magnesium sulfate had a poorer quality of bowel preparations (OR=0.6, 95% CI 0.4–0.9; p<0.05, whereas the quality of bowel preparation was significantly improved by using sodium sulfate (OR=5.7, 95% CI 5.4–6.1; p<0.001 and sodium phosphate (OR=2.1, 95% CI 1.8–2.5; p<0.001. For those who had adequate bowel preparation, the better quality of preparation significantly increased the detection rate of advanced adenoma (5.0, 3.6, and 2.9% for excellent, good, and fair, respectively. Conclusion: When possible, sodium sulfate–based preparations should be recommended in the community setting for colonoscopy because of their high quality of bowel preparation.

  20. Polish country study to address climate change: Strategies of the GHG`s emission reduction and adaptation of the Polish economy to the changed climate. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-01-01

    The Polish Country Study Project was initiated in 1992 as a result of the US Country Study Initiative whose objective was to grant the countries -- signatories of the United Nations` Framework Convention on Climate Change -- assistance that will allow them to fulfill their obligations in terms of greenhouse gases (GHG`s) inventory, preparation of strategies for the reduction of their emission, and adapting their economies to the changed climatic conditions. In February 1993, in reply to the offer from the United States Government, the Polish Government expressed interest in participation in this program. The Study proposal, prepared by the Ministry of Environmental Protection, Natural Resources and Forestry was presented to the US partner. The program proposal assumed implementation of sixteen elements of the study, encompassing elaboration of scenarios for the strategy of mission reduction in energy sector, industry, municipal management, road transport, forestry, and agriculture, as well as adaptations to be introduced in agriculture, forestry, water management, and coastal management. The entire concept was incorporated in macroeconomic strategy scenarios. A complementary element was the elaboration of a proposal for economic and legal instruments to implement the proposed strategies. An additional element was proposed, namely the preparation of a scenario of adapting the society to the expected climate changes.

  1. Study of microbial perchlorate reduction: Considering of multiple pH, electron acceptors and donors

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Xing [Key Laboratory of Water Pollution Control and Recycling (Shandong), School of Environmental Science and Engineering, Shandong University, Jinan 250100 (China); Gao, Baoyu, E-mail: bygao@sdu.edu.cn [Key Laboratory of Water Pollution Control and Recycling (Shandong), School of Environmental Science and Engineering, Shandong University, Jinan 250100 (China); Jin, Bo [School of Chemical Engineering, The University of Adelaide, Adelaide SA 5005,Australia (Australia); Zhen, Hu [Key Laboratory of Water Pollution Control and Recycling (Shandong), School of Environmental Science and Engineering, Shandong University, Jinan 250100 (China); Wang, Xiaoyi [CSIRO Land and Water, Gate 5, Waite Road, Urrbrae, SA 5064 (Australia); Dai, Ming [School of Chemical Engineering, The University of Adelaide, Adelaide SA 5005,Australia (Australia)

    2015-03-21

    Graphical abstract: Schemes of perchlorate reduction in ClO{sub 4}{sup −}/ClO{sub 3}{sup −}–NO{sub 3}{sup −} e{sup −}acceptor systems. - Highlights: • We created a multiple electron acceptor/donor system for ClO{sub 4}{sup −} reduction. • Nitrate reduction was inhibited when using perchlorate-grown Azospira sp. KJ. • Reduction proceeded as an order of ClO{sub 3}{sup −}, ClO{sub 4}{sup −}and NO{sub 3}{sup −}. • Oxidation of acetate was inhibited by succinate in acetate–succinate series. - Abstract: Bioremediation of perchlorate-cotaminated water by a heterotrophic perchlorate reducing bacterium creates a multiple electron acceptor-donor system. We experimentally determined the perchlorate reduction by Azospira sp. KJ at multiple pH, electron acceptors and donors systems; this was the aim of this study. Perchlorate reduction was drastically inhibited at the pH 6.0, and the maximum reduction of perchlorate by Azospira sp. KJ was observed at pH value of 8.0. Perchlorate reduction was retarded in ClO{sub 4}{sup −}–ClO{sub 3}{sup −}, ClO{sub 4}{sup −}–ClO{sub 3}{sup −}–NO{sub 3}{sup −},and ClO{sub 4}{sup −}–NO{sub 3}{sup −} acceptor systems, while being completely inhibited by the additional O{sub 2} in the ClO{sub 4}{sup −}–O{sub 2} acceptor system. The reduction proceeded as an order of ClO{sub 3}{sup −}, ClO{sub 4}{sup −}, and NO{sub 3}{sup −} in the ClO{sub 4}{sup −}–ClO{sub 3}{sup −}–NO{sub 3}{sup −} system. K{sub S,}v{sub max}, and q{sub max} obtained at different e{sup −} acceptor and donor conditions are calculated as 140.5–190.6 mg/L, 8.7–13.2 mg-perchlorate/L-h, and 0.094–0.16 mg-perchlorate/mg-DW-h, respectively.

  2. Leucocyte specific antinuclear antibodies. Preparation and fluorescence study.

    Science.gov (United States)

    Lampert, I A; Evans, D J; Chesterton, C J

    1975-09-11

    Tissue and species specific anti-nuclear sera detectable by immunofluorescence were produced by immunising rabbits with D.N.A.-non-histone protein extract from human leucocytes. This is a potentially valuable method for the morphological study of differentiation.

  3. Evaluation of Mirasol pathogen reduction system by artificially contaminating platelet concentrates with Staphylococcus epidermidis: A pilot study from India

    Directory of Open Access Journals (Sweden)

    Kabita Chatterjee

    2016-01-01

    Full Text Available Background and Objectives: This study was conducted to assess the efficacy of Mirasol pathogen reduction system for platelets aimed at preventing bacterial regrowth by spiking buffy coat pooled platelets (BCPP with clinically relevant load of Staphylococous epidermidis. Materials and Methods: BCPP units were prepared using Teruflex BP-kit with Imugard III-S-PL (Terumo BCT, Tokyo, Japan. Two BCPP units were pooled, of which 40 ml of negative control (NC was removed. The remaining volume of the platelet unit was inoculated with clinically relevant load of bacteria (total of 30 CFU of S. epidermidis in 1 ml; following this the platelet unit was split into two parts. One part served as positive control (PC and the other part was subjected to pathogen reduction technique (Mirasol PRT, CaridianBCT Biotechnologies, Lakewood, CO, USA. Bacterial detection was performed using BacT/ALERT system, controls after day 1 and day 7 following inoculation of bacteria and on day 7 for Mirasol-treated unit. Results: Of the 32 treatment cycles, 28 were valid and 4 were invalid. No regrowth was observed in 96.4% (27 of 28 after treatment with Mirasol pathogen reduction system. Of four invalid tests, on two instances the NC showed growth, whereas in other 2 no regrowth was detected in 7th day PC. Bacterial screening of PCs by BacT/ALERT after 24 h of incubation was 28.6%, whereas the effectiveness increased to 100% when incubated for 7 days. Conclusions: Mirasol system was effective in inactivating S.epidermidis when it was deliberately inoculated into BCPP at clinically relevant concentrations. Such systems may significantly improve blood safety by inactivating traditional and emerging transfusion-transmitted pathogens.

  4. Evaluation of Mirasol pathogen reduction system by artificially contaminating platelet concentrates with Staphylococcus epidermidis: A pilot study from India.

    Science.gov (United States)

    Chatterjee, Kabita; Zaman, Shamsuz; Chaurasia, Rahul; Singh, Surinder; Keil, Shawn D; Tewari, Shalini; Bisht, Akanksha; Agarwal, Nitin; Rout, Diptiranjan; Chand, Subhash; Saha, Kallol

    2016-01-01

    This study was conducted to assess the efficacy of Mirasol pathogen reduction system for platelets aimed at preventing bacterial regrowth by spiking buffy coat pooled platelets (BCPP) with clinically relevant load of Staphylococous epidermidis. BCPP units were prepared using Teruflex BP-kit with Imugard III-S-PL (Terumo BCT, Tokyo, Japan). Two BCPP units were pooled, of which 40 ml of negative control (NC) was removed. The remaining volume of the platelet unit was inoculated with clinically relevant load of bacteria (total of 30 CFU of S. epidermidis in 1 ml); following this the platelet unit was split into two parts. One part served as positive control (PC) and the other part was subjected to pathogen reduction technique (Mirasol PRT, CaridianBCT Biotechnologies, Lakewood, CO, USA). Bacterial detection was performed using BacT/ALERT system, controls after day 1 and day 7 following inoculation of bacteria and on day 7 for Mirasol-treated unit. Of the 32 treatment cycles, 28 were valid and 4 were invalid. No regrowth was observed in 96.4% (27 of 28) after treatment with Mirasol pathogen reduction system. Of four invalid tests, on two instances the NC showed growth, whereas in other 2 no regrowth was detected in 7(th) day PC. Bacterial screening of PCs by BacT/ALERT after 24 h of incubation was 28.6%, whereas the effectiveness increased to 100% when incubated for 7 days. Mirasol system was effective in inactivating S. epidermidis when it was deliberately inoculated into BCPP at clinically relevant concentrations. Such systems may significantly improve blood safety by inactivating traditional and emerging transfusion-transmitted pathogens.

  5. Structural Studies of BaTiO 3 Ferroelectric Material Prepared by ...

    African Journals Online (AJOL)

    Structural Studies of BaTiO 3 Ferroelectric Material Prepared by Green Chemistry ... Science, Technology and Arts Research Journal ... The microstructure of the samples was investigated by using Scanning electron microscope (SEM).

  6. A study about expectations of the athletes from their coaches resting in Olympics preparation camping Gaziantep

    OpenAIRE

    OZTURK, Huseyin; AVSAR, Omur; CILDIR, Idris

    2015-01-01

    This is a descriptive study, aims to specify the expectations of the athletes from their coaches resting in Olympic Preparation Camp. A total of 120 athletes resting in Olympic Preparation Camp in Gaziantep participated the research including 94 men and 26 women. The expectation scale (ASABÖ, 2008) was used for collecting the data of this research which was used in scientific study done by Güzel before (7). The scale consist of three sub-dimensions; behavior, coaching model and personality. S...

  7. COMPUTATIONAL MODELING AND EXPERIMENTAL STUDIES ON NOx REDUCTION UNDER PULVERIZED COAL COMBUSTION CONDITIONS

    Energy Technology Data Exchange (ETDEWEB)

    Subha K. Kumpaty; Kannikeswaran Subramanian; Victor P. Nokku; Tyrus L. Hodges; Adel Hassouneh; Ansumana Darboe; Sravan K. Kumpati

    1998-06-01

    In this work, both computer simulation and experimental studies were conducted to investigate several strategies for NO{sub x} reduction under pulverized coal combustion conditions with an aim to meet the stringent environmental standards for NO{sub x} control. Both computer predictions and reburning experiments yielded favorable results in terms of NO{sub x} control by reburning with a combination of methane and acetylene as well as non-selective catalytic reduction of NO{sub x} with ammonia following reburning with methane. The greatest reduction was achieved at the reburning stoichiometric ratio of 0.9; the reduction was very significant, as clearly shown in Chapters III and V. Both the experimental and computational results favored mixing gases: methane and acetylene (90% and 10% respectively) and methane and ammonia (98% and 2%) in order to get optimum reduction levels which can not be achieved by individual gases at any amounts. Also, the above gaseous compositions as reburning fuels seemed to have a larger window of stoichiometric ratio (SR2 < 0.9) as opposed to just methane (SR2=0.9) so as to reduce and keep NO{sub x} at low ppm levels. From the various computational runs, it has been observed that although there are several pathways that contribute to NO{sub x} reduction, the key pathway is NO {r_arrow} HCN {r_arrow} NH{sub 3} {r_arrow} N{sub 2} + H{sub 2}. With the trends established in this work, it is possible to scale the experimental results to real time industrial applications using computational calculations.

  8. Successful Study Abroad: Tips for Student Preparation, Immersion, and Postprocessing

    Science.gov (United States)

    Kruse, Julia; Brubaker, Cate

    2007-01-01

    This article discusses components that can make study abroad programs more effective so that students successfully improve their language and culture competency and gain a more sophisticated understanding of the host culture. First, the authors offer ideas for language instructors at home on how to integrate culture learning into the classroom and…

  9. Study on Preparation of 182Hf AMS Standards

    Institute of Scientific and Technical Information of China (English)

    YINXin-yi; JIANGShan; HEMing; ZHANGChun-hua; ZHANGSheng-dong

    2003-01-01

    The neutron-rich isotope 182Hf with its half-life of (9±2)×106 a produced by neutron activation can be used to determine the neutron flux of some places, in order to study the transport of radioactive nuclides and the safe disposal of nuclear waste. AMS is a kind of relative measurement method with high sensitivity (10-15), it requires corresponding standard samples.

  10. Genotoxicity studies on a high-purity rebaudioside A preparation.

    Science.gov (United States)

    Williams, Lonnie D; Burdock, George A

    2009-08-01

    Rebaudioside A (Reb A) is a steviol glycoside isolated from the leaves of the Stevia rebaudiana plant. This non-nutritive, natural sweetener is reported to be 250-450 times sweeter than sucrose and has potential for wide use in the US diet, and is used in Japan and South America today. The safety of Reb A has been investigated in several recently published studies and information on genotoxicity is described herein. Reb A was investigated for its potential to induce genotoxicity in three in vitro and two in vivo assays (conducted according to OECD guidelines). Reb A was non-mutagenic in an Ames test using Salmonella typhimurium and Escherichia coli, in a chromosomal aberration test using Chinese Hamster V79 cells and in a mouse lymphoma assay using L5178Y+/- cells, all studies were conducted at concentrations up to 5000 microg/ml, with and without metabolic activation. Also, Reb A was non-genotoxic in a bone marrow micronucleus test in mice at doses up 750 mg/kg bw and in an unscheduled DNA synthesis test in rats at 2000 mg/kg bw. These studies provide additional evidence that Reb A is not genotoxic at the doses tested and further support the generally recognized as safe determination of Reb A.

  11. Cost Effectiveness of Screening Colonoscopy Depends on Adequate Bowel Preparation Rates – A Modeling Study

    Science.gov (United States)

    Kingsley, James; Karanth, Siddharth; Revere, Frances Lee

    2016-01-01

    Background Inadequate bowel preparation during screening colonoscopy necessitates repeating colonoscopy. Studies suggest inadequate bowel preparation rates of 20–60%. This increases the cost of colonoscopy for our society. Aim The aim of this study is to determine the impact of inadequate bowel preparation rate on the cost effectiveness of colonoscopy compared to other screening strategies for colorectal cancer (CRC). Methods A microsimulation model of CRC screening strategies for the general population at average risk for CRC. The strategies include fecal immunochemistry test (FIT) every year, colonoscopy every ten years, sigmoidoscopy every five years, or stool DNA test every 3 years. The screening could be performed at private practice offices, outpatient hospitals, and ambulatory surgical centers. Results At the current assumed inadequate bowel preparation rate of 25%, the cost of colonoscopy as a screening strategy is above society’s willingness to pay (<$50,000/QALY). Threshold analysis demonstrated that an inadequate bowel preparation rate of 13% or less is necessary before colonoscopy is considered more cost effective than FIT. At inadequate bowel preparation rates of 25%, colonoscopy is still more cost effective compared to sigmoidoscopy and stool DNA test. Sensitivity analysis of all inputs adjusted by ±10% showed incremental cost effectiveness ratio values were influenced most by the specificity, adherence, and sensitivity of FIT and colonoscopy. Conclusions Screening colonoscopy is not a cost effective strategy when compared with fecal immunochemical test, as long as the inadequate bowel preparation rate is greater than 13%. PMID:27936028

  12. Sustained action tetracycline preparation--tetrabid-organon blood level study.

    Science.gov (United States)

    Lucas, C R; Mugglestone, C J; Thomas, D R

    1977-01-01

    A comparison of the plasma levels of tetracycline obtained whilst taking standard therapeutic doses of Tetrabid-Organon was made in twelve healthy volunteers. Two standard production batches were used in the study which was conducted under double-blind conditions. Sampling 12 hours and 8 hours after dosing showed no significant differences in plasma levels, with each batch. Even at these lowest levels satisfactory concentrations were rapidly obtained following initial administration, and were maintained when the drug was given at 12-hourly intervals. No side-effects of the drug were noted.

  13. Mental preparation for hockey players : study on self-talk and mental imagary

    OpenAIRE

    Allenius, Jani; Lehtonen, Matias

    2015-01-01

    This bachelor thesis is a study of mental preparation, and how to go it through with players. Objective is to find easy way to start teaching mental preparation for players and two main themes were mental imagery and self-talk. This report includes theory part of different consepts of mental preparation and extensive theory parts of mental imagery and self-talk. The practical section is made of the lessons that players were taught during the season and assignment that they were given. The ...

  14. [Studies on cyclodextrin inclusion complexes of Dragon's blood and its tablets preparation].

    Science.gov (United States)

    Han, Bin-Bin; Pei, Hui-Na; Sun, Hai-Song; Ning, Quan-Kui; Ren, Yong

    2008-09-01

    To study the cyclodextrin inclusion complexes of Dragon's blood for improving the drug solubility and the preparation. The inclusion complexes were prepared with beta-cyclodextrin, HP-beta-cyclodextrin, SBE-beta-cyclodextrin and confirmed by DTA. The activity of the inclusion complex was tested by animal experiments. Inclusion complexes tablets were prepared and the dissolution test was performed. The solubility of inclusion complexes was increased to 13. 75-168. 39 times. The activity of the inclusion complex was markedly improved, and dissolution rate was 78.69%. The cyclodextrin inclusion complexes of Dragon's blood have a good solubility, dissolution rate and pharmacological activity.

  15. Study on preparation of β-cyclodextrin encapsulation tea extract.

    Science.gov (United States)

    Haidong, Liang; Fang, Yu; Zhihong, Tong; Changle, Ren

    2011-11-01

    Microencapsulation of ethanol extract of tea was performed in this study. In order to microencapsulate, β-cyclodextrin was used as wall material. Ethanol extract of tea was used as the core material. Microcapsules in the solid form were obtained by drying the emulsions. RSM showed that optimal processing parameters were as followings: core material/wall material 1/4, β-cyclodextrin content 16%, stirring time 30 min and stirring temperature 200°C. Pharmacological activities of β-cyclodextrin encapsulation tea extract were determined. It was found that β-cyclodextrin encapsulation tea extract could enhance BMD, BMC and bone Ca, Zn and Cu contents. In addition, β-cyclodextrin encapsulation tea extract could still reduce blood Ca contents. These results indicated that β-cyclodextrin encapsulation tea extract was useful for improving bone quality in aged animals.

  16. X-ray absorption spectroscopy study on the thermal and hydrazine reduction of graphene oxide

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Xianqing, E-mail: lxq@gxu.edu.cn [The Colleague of Physics Science and Technology, Guangxi University, Nanning 530004 (China); Wang, Yu [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029 (China); Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204 (China); Zheng, Huiyuan [The Colleague of Physics Science and Technology, Guangxi University, Nanning 530004 (China); Wu, Ziyu, E-mail: wuzy@ustc.edu.cn [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029 (China)

    2014-10-15

    Highlights: • XAS study of GO and reduced GO was performed. • Detailed evolution of the electronic structures and chemical bonding of GO was revealed. • A new efficient route for the reduction of GO is proposed. - Abstract: X-ray absorption spectroscopy (XAS) was applied to systemically investigate the deoxygenation of graphene oxide (GO) via annealing and hydrazine treatment. Detailed evolution of the electronic structures and chemical bonding of GO was presented. The enhanced intensity of π{sup *} resonance and the appearance of splitting σ{sup *} resonance in C K-edge XAS spectra suggest high extents of recoveries of π-conjugation upon reduction using thermal annealing or hydrazine. Experimental results revealed that the carboxyl as well as epoxide and hydroxyl groups on the surface of GO were thermally reduced first, followed by the more difficult removal of carbonyl and cyclic ether groups at higher temperatures. The hydrazine reduction could remove epoxide, hydroxyl and carboxyl groups effectively, whereas the carbonyl groups were partially reduced with the incorporation of nitrogen species simultaneously. The residual oxygen functional groups on hydrazine-reduced GO could be further removed after modest thermal annealing. It was proposed that a combination of both types of reductions would give the best deoxygenation efficiency for the production of graphene.

  17. Quantum chemical study on the mechanism of enantioselective reduction of prochiral ketones catalyzed by oxazaborolidines

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The ab initio molecular orbital study on the mechanism of enantioselective reduction of 3,3-dimethyl butanone-2 with borane catalyzed by chiral oxazaborolidine is performed. As illus trated, this enantioselective reduction is exothermic and goes mainly through the formations of the catalyst-borane adduct, the catalyst-borane-3,3-dimethyl butanone-2 adduct, and the cata lyst-alkoxyborane adduct with a B-O-B-N 4-member ring and through the decomposition of the catalyst-alkoxyborane adduct with the regeneration of the catalyst. During the hydride transfer in the catalyst-borane-3,3-dimethyl butanone-2 adduct to form the catalyst-alkoxyborane adduct, the hydride transfer and the formation of the B-O-B-N 4-member ring in the catalyst-alkoxyborane ad duct happen simultaneously. The controlling step for the reduction is the transfer of hydride from the borane moiety to the carbonyl carbon of 3,3-dimethyl butanone-2. The transition state for the hydride transfer is a twisted chair structure and the reduction leads to R-chiral alcohols.

  18. A simulation study of harmonics regeneration in noise reduction for electric and acoustic stimulation.

    Science.gov (United States)

    Hu, Yi

    2010-05-01

    Recent research results show that combined electric and acoustic stimulation (EAS) significantly improves speech recognition in noise, and it is generally established that access to the improved F0 representation of target speech, along with the glimpse cues, provide the EAS benefits. Under noisy listening conditions, noise signals degrade these important cues by introducing undesired temporal-frequency components and corrupting harmonics structure. In this study, the potential of combining noise reduction and harmonics regeneration techniques was investigated to further improve speech intelligibility in noise by providing improved beneficial cues for EAS. Three hypotheses were tested: (1) noise reduction methods can improve speech intelligibility in noise for EAS; (2) harmonics regeneration after noise reduction can further improve speech intelligibility in noise for EAS; and (3) harmonics sideband constraints in frequency domain (or equivalently, amplitude modulation in temporal domain), even deterministic ones, can provide additional benefits. Test results demonstrate that combining noise reduction and harmonics regeneration can significantly improve speech recognition in noise for EAS, and it is also beneficial to preserve the harmonics sidebands under adverse listening conditions. This finding warrants further work into the development of algorithms that regenerate harmonics and the related sidebands for EAS processing under noisy conditions.

  19. Infrared Spectroscopy Studies on sol-gel prepared alumina Powders

    Directory of Open Access Journals (Sweden)

    Majid JAFAR TAFRESHI

    2015-03-01

    Full Text Available Gamma-alumina fine particles were synthesized by sol-gel process. Aluminum tri-sec-butoxide (ATB, anhydrous ethyl alcohol (EtOH, water (H2O and hydrochloric acid (HCl were used as starting materials. Different samples were synthesized with EtOH/ATB=60/1, HCl/ATB=0.08/1 and H2O/ATB=1/1 ratios and calcined at different temperatures. Molar ratios of H2O/ATB (from 1 to 25 and HCl/ATB (from 0.08 to 0.4 were changed for some other samples, during synthesizing process. The products were characterized by both XRD and FTIR measurements. Studies were carried out on the effect of calcination temperature and change of H2O/ATB and HCl/ATB ratios on structure and processes involved in phase transformations.DOI: http://dx.doi.org/10.5755/j01.ms.21.1.4872

  20. The effect of secondary school study skills preparation on first-year university achievement

    NARCIS (Netherlands)

    Jansen, Ellen P. W. A.; Suhre, Cor J. M.

    2010-01-01

    Although many studies have revealed the importance of study skills for students' first-year performance and college retention, the extent of the impact of study skills preparation on students' academic achievement is less clear. This paper explores the impact of pre-university study skills

  1. The effect of secondary school study skills preparation on first-year university achievement

    NARCIS (Netherlands)

    Jansen, Ellen P. W. A.; Suhre, Cor J. M.

    2010-01-01

    Although many studies have revealed the importance of study skills for students' first-year performance and college retention, the extent of the impact of study skills preparation on students' academic achievement is less clear. This paper explores the impact of pre-university study skills preparati

  2. The effect of secondary school study skills preparation on first-year university achievement

    NARCIS (Netherlands)

    Jansen, Ellen P. W. A.; Suhre, Cor J. M.

    2010-01-01

    Although many studies have revealed the importance of study skills for students' first-year performance and college retention, the extent of the impact of study skills preparation on students' academic achievement is less clear. This paper explores the impact of pre-university study skills preparati

  3. Preparation of radioactive rare earth targets for neutron capture study

    Energy Technology Data Exchange (ETDEWEB)

    Miller, G. G. (Geoffrey G.); Rogers, P. S. Z. (Pamela S. Z.); Palmer, P. D. (Phillip D.); Dry, D. E. (Donald E.); Rundberg, R. S. (Robert S.); Fowler, Malcolm M.; Wilhelmy, J. B. (Jerry B.)

    2002-01-01

    The understanding of thc details of nucleosynthesis in stars remains a great challenge. Though the basic mechanisms governing the processes have been known since the pioneering work of Burbidge, Burbidge, Fowler and Hoyle (l), we are now evolving into a condition where we can ask more specific questions. Of particular interest are the dynamics of the s ('slow') process. In this process the general condition is one in which sequential neutron captures occur at time scales long compared with the beta decay half lives of the capturing nuclides. The nucleosynthesis period for C or Ne burning stellar shells is believed to be in the year to few year time frame (2). This means that radionuclides with similar half lives to this burning period serve as 'branch point' nuclides. That is, there will be a competition between a capture to the next heavier isotope and a beta decay to the element of nexl higher atomic number. By understanding the abundances of these competing reactions we can learn about the dynamics of the nucleosynthesis process in the stellar medium. Crucial to this understanding is that we have a knowledge of the underlying neutron reaction cross sections on these unstable nuclides in the relevant stellar energy regions (neutrons of 0.1-100 KeV). Tm (1.9 years) and ls'Sm (90 ycws) have decay properties that permit their handling in an open fume hood. These Iwo were therefore selected to be the first radionuclides for neutron capture study in what will be an ongoing effort.

  4. Studies on the Preparation Properties and Drug Loading of theStarch Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    WangJin; HouXinpu

    2001-01-01

    On the basis of studies of starch microspheres, we carried out the research program of starch nanoparticles(SNP)which included preparation, physical and chemical properties and drug loading. The SNP was prepared using reversedphase-microemulsion polymerization method, with soluble starch as raw material. The particle size, quantity ofphosphorous, degradability, scanning electron microgragh, IR spectra and stability of SNP were investigated. Thepharmacodynamics and concentration-time curve of insulin starch nanoparticles were determined.

  5. Examination of surface phenomena of V₂O₅ loaded on new nanostructured TiO₂ prepared by chemical vapor condensation for enhanced NH₃-based selective catalytic reduction (SCR) at low temperatures.

    Science.gov (United States)

    Cha, Woojoon; Yun, Seong-Taek; Jurng, Jongsoo

    2014-09-01

    In this article, we describe the investigation and surface characterization of a chemical vapor condensation (CVC)-TiO2 support material used in a V2O5/TiO2 catalyst for enhanced selective catalytic reduction (SCR) activity and confirm the mechanism of surface reactions. On the basis of previous studies and comparison with a commercial TiO2 catalyst, we examine four fundamental questions: first, the reason for increased surface V(4+) ion concentrations; second, the origin of the increase in surface acid sites; third, a basis for synergistic influences on improvements in SCR activity; and fourth, a reason for improved catalytic activity at low reaction temperatures. In this study, we have cited the result of SCR with NH3 activity for removing NOx and analyzed data using the reported result and data from previous studies on V2O5/CVC-TiO2 for the SCR catalyst. In order to determine the properties of suitable CVC-TiO2 surfaces for efficient SCR catalysis at low temperatures, CVC-TiO2 specimens were prepared and characterized using techniques such as XRD, BET, HR-TEM, XPS, FT-IR, NH3-TPD, photoluminescence (PL) spectroscopy, H2-TPR, and cyclic voltammetry. The results obtained for the CVC-TiO2 materials were also compared with those of commercial TiO2.

  6. The Role of Logistics in Practical Levelized Cost of Energy Reduction Implementation and Government Sponsored Cost Reduction Studies: Day and Night in Offshore Wind Operations and Maintenance Logistics

    DEFF Research Database (Denmark)

    Poulsen, Thomas; Hasager, Charlotte Bay; Jensen, Christian Munk

    2017-01-01

    This paper reveals that logistics make up at least 17% of annual operational expenditure costs for offshore wind farms. Annual operational expenditure is found to vary by a factor of 9.5, making its share of levelized cost of energy for offshore wind range from 13% to 57%. These are key findings...... contrast to the shore-based office personnel who develop studies directing cost reduction efforts. This paper details the company motivation to join industry-wide cost reduction initiatives. A business case for offshore wind operations and maintenance logistics yielding 1% savings in levelized cost...... of a 20-month research project targeting cost reduction initiatives for offshore wind systems. The findings reveal that cost-out measures are difficult to implement due to cultural differences. Implementation efforts are rendered by personnel located offshore in a harsh sea environment which is in stark...

  7. Feature-resolved computational and analytical study of laminar drag reduction by superhydrophobic surfaces

    Science.gov (United States)

    Li, Yixuan; Alame, Karim; Mahesh, Krishnan

    2017-05-01

    Direct numerical simulations are used to study the drag reduction by superhydrophobic surfaces in laminar channel flow. Resolved multiphase simulations using the volume of fluid methodology are performed to study the effects of groove geometry, interface shear rate, and meniscus penetration independently. An analytical solution for the flow in a laminar channel with a grooved surface with a gas pocket within is obtained. The solution accounts for both the groove geometry and the trapped fluid properties, and shows good agreement with simulation results. The solution is used to propose a scaling law that collapses data across fully wetted to fully gas-filled regimes. The trapped gas is simulated as both flat and meniscal interfaces. The drag reduction initially increases with interface deflection into the groove and then decreases for large deflections as the interface velocity approaches zero due to the proximity to the bottom of the groove.

  8. Accident reduction factors and causal inference in traffic safety studies: a review.

    Science.gov (United States)

    Davis, G A

    2000-01-01

    Accident reduction factors are used to predict the change in accident occurrence which a countermeasure can be expected to cause. Since ethical and legal obstacles preclude the use of randomized experiments when evaluating traffic safety improvements, empirical support for the causal effectiveness of accident countermeasures comes entirely from observational studies. Drawing on developments in causal inference initiated by Donald Rubin, it is argued here that the mechanism by which sites are selected for application of a countermeasure should be included as part of a study's data model, and that when important features of the selection mechanism are neglected, existing methods for estimating accident reduction factors become inconsistent. A promising, but neglected, way out of these difficulties lies in developing rational countermeasure selection methods which also support valid causal inference of countermeasure effects.

  9. The reduction process of phytic acid-silver ion system: A pulse radiolysis study

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Ravi [Radiation and Photochemistry Division, Chemistry Group, Bhabha Atomic Research Center, Mumbai 400 085 (India)]. E-mail: rjudrin@yahoo.com; Mukherjee, Tulsi [Radiation and Photochemistry Division, Chemistry Group, Bhabha Atomic Research Center, Mumbai 400 085 (India)

    2007-05-15

    Reduction of silver ion in a silver-phytic acid (1:1 ratio) system has been studied using pulse radiolysis technique. Time-resolved transformation of the intermediates, Ag{sup +{yields}}Ag{sup 0{yields}}Ag{sub 2} {sup +{yields}}Ag{sub 3} {sup 2+}, has been clearly observed in the reduction of silver-phytic acid (1:1) system. The effect of phytic acid on the formation and decay of initial silver clusters has been also studied. The surface plasmon absorption band of stable silver nanoparticle (410 nm) and dynamic light scattering technique has been used to characterize the nanoparticles and measure the average size (R {sub av}=100 nm)

  10. Coffee enema for preparation for small bowel video capsule endoscopy: a pilot study.

    Science.gov (United States)

    Kim, Eun Sun; Chun, Hoon Jai; Keum, Bora; Seo, Yeon Seok; Jeen, Yoon Tae; Lee, Hong Sik; Um, Soon Ho; Kim, Chang Duck; Ryu, Ho Sang

    2014-07-01

    Coffee enemas are believed to cause dilatation of bile ducts and excretion of bile through the colon wall. Proponents of coffee enemas claim that the cafestol palmitate in coffee enhances the activity of glutathione S-transferase, an enzyme that stimulates bile excretion. During video capsule endoscopy (VCE), excreted bile is one of the causes of poor preparation of the small bowel. This study aimed to evaluate the feasibility and effect of coffee enema for preparation of the small bowel during VCE. In this pilot study, 17 of 34 patients were assigned to the coffee enema plus polyethylene glycol (PEG) 2 L ingestion group, whereas the 17 remaining control patients received 2 L of PEG only. The quality of bowel preparation was evaluated in the two patient groups. Bowel preparations in the proximal segments of small bowel were not differ between two groups. In the mid and distal segments of the small intestine, bowel preparations tend to be better in patients who received coffee enemas plus PEG than in patients who received PEG only. The coffee enema group did not experience any complications or side effects. Coffee enemas may be a feasible option, and there were no clinically significant adverse events related to coffee enemas. More prospective randomized studies are warranted to improve small bowel preparation for VCE.

  11. Study of the influence of homologous serum globulin preparations on the intestinal automicroflora in irradiated mice

    Energy Technology Data Exchange (ETDEWEB)

    Pinegin, B.V.; Klemparskaya, N.N.; Mal' tsev, V.N.; Korshunov, G.A.; Shal' nova, G.A.; Kuz' mina, T.D.

    1984-09-01

    In spite of considerable experience of practical use of serum globulin preparations, their effect on automicroflora wasn't studied. The favorable effect of therapeutic injection of homologous serum globulin preparations on automicroflora of small and large intestine of mices was established for the model of acute radiation sickness caused by /sup 60/Co irradiation with 700 R dose. The effect of injecting two types of globulin preparations was studied: ones prepared of blood of intact and hemostimulated mices (to increase the content of normal antitissue antibodies in the serum). Besides the general globulin fraction isolated by ammonium sulfate precipitation a study was made on the effect of purified IgG and IgM preparations. Threefold subcutaneous or intraperitoneal globulin in ection of 1 ..mu..g dose in a mice prevented after 2, 24, 48 h after irradiation the development of bacteriosis, typical for radiation injury - decreased accumulation of putrefactive bacteria and reduced the suppression of lactobacilli content. Globulin preparations and fractions of hemostimulated mice serum, enriched by normal antitissue antibodies are the most effective ones.

  12. Comparative study on sulphur reduction from heavy petroleum - Solvent extraction and microwave irradiation approach

    Energy Technology Data Exchange (ETDEWEB)

    Mohammed, Abdullahi Dyadya; Isah, Abubakar Garba; Umaru, Musa; Ahmed, Shehu [Department of Chemical Engineering, Federal University of Technology, P.M.B 65, Minna (Nigeria); Abdullahi, Yababa Nma [National Petroleum Investment Management Services (Nigeria National Petroleum Corporation), Lagos (Nigeria)

    2012-07-01

    Sulphur- containing compounds in heavy crude oils are undesirable in refining process as they affect the quality of the final product, cause catalyst poisoning and deactivation in catalytic converters as well as causing corrosion problems in oil pipelines, pumps and refining equipment aside environmental pollution from their combustion and high processing cost. Sulphur reduction has being studied using microwave irradiation set at 300W for 10 and 15minutes and oxidative- solvent extraction method using n- heptane and methanol by 1:1, 1:2 and 1:3 crude- solvent ratios after being oxidized with hydrogen peroxide, H2O2 oxidants. Percentage sulphur removal with n- heptane solvent by 1:1 and 1:2 are 81.73 and 85.47%; but extraction using methanol by different observed ratios gave less sulphur reduction. Indeed when microwave irradiated at 300W for 10 and 15minutes, 53.68 and 78.45% reduction were achieved. This indicates that microwave irradiation had caused oxidation by air in the oven cavity and results to formation of alkyl radicals and sulphoxide from sulphur compound in the petroleum. The prevailing sulphur found in the crude going by FT-IR results is sulphides which oxidized to sulphoxide or sulphones. It is clear that sulphur extraction with heptane is more efficient than microwave irradiation but economically due to demands for solvent and its industrial usage microwave irradiation can serve as alternative substitute for sulphur reduction in petroleum. Sulphur reduction by microwave radiation should be up- scaled from laboratory to a pilot plant without involving extraction column in the refining.

  13. Numerical Study of the Reduction Process in an Oxygen Blast Furnace

    Science.gov (United States)

    Zhang, Zongliang; Meng, Jiale; Guo, Lei; Guo, Zhancheng

    2016-02-01

    Based on computational fluid dynamics, chemical reaction kinetics, principles of transfer in metallurgy, and other principles, a multi-fluid model for a traditional blast furnace was established. The furnace conditions were simulated with this multi-fluid mathematical model, and the model was verified with the comparison of calculation and measurement. Then a multi-fluid model for an oxygen blast furnace in the gasifier-full oxygen blast furnace process was established based on this traditional blast furnace model. With the established multi-fluid model for an oxygen blast furnace, the basic characteristics of iron ore reduction process in the oxygen blast furnace were summarized, including the changing process of the iron ore reduction degree and the compositions of the burden, etc. The study found that compared to the traditional blast furnace, the magnetite reserve zone in the furnace shaft under oxygen blast furnace condition was significantly reduced, which is conducive to the efficient operation of blast furnace. In order to optimize the oxygen blast furnace design and operating parameters, the iron ore reduction process in the oxygen blast furnace was researched under different shaft tuyere positions, different recycling gas temperatures, and different allocation ratios of recycling gas between the hearth tuyere and the shaft tuyere. The results indicate that these three factors all have a substantial impact on the ore reduction process in the oxygen blast furnace. Moderate shaft tuyere position, high recycling gas temperature, and high recycling gas allocation ratio between hearth and shaft could significantly promote the reduction of iron ore, reduce the scope of the magnetite reserve zone, and improve the performance of oxygen blast furnace. Based on the above findings, the recommendations for improvement of the oxygen blast furnace design and operation were proposed.

  14. [Experimental study on rainfall-runoff pollutant reduction by urban green space].

    Science.gov (United States)

    Cheng, Jiang; Yang, Kai; Lü, Yong-Peng; Li, Bo; Lü, Shu-Hua

    2009-11-01

    Based on the state that non-pointed pollution caused by urban rainfall-runoff was one of the major factors which led to urban surface water contaminated and ecology deteriorated, a soil aquifer treatment system was built to experimentally study the pollution reduction effectiveness of green space, and the impacts of land cover, influent concentration, soil depth, hydraulic loading rate and residence time were analyzed. The results exhibit that green space has a better and stabilized ability to reduce three representative urban rainfall-runoff pollution concentrations, which COD are 44.5, 144.3, 487.2 mg x L(-1), NH4(+) -N are 4.27, 11.44, 36.61 mg x L(-1) and TP are 0.98, 2.85, 9.66 mg x L(-1), respectively, and with 8.15, 7.13 and 6.12 cm x h(-1) hydraulic loading rate, respectively. The pollution reduction rates of COD, NH4(+) -N and TP by green space are 33.41%-37.14%, 58.74%-61.49% and 63.65%-67.08%, respectively. The effect of land cover to pollution reduction rate is not significant because of the limitation of oxygen and hydraulic residence time. When pollution concentration increases, the comprehensive pollution reduction ability of green space is kept in 50%-60%, with a little increased tendency. Pollution reduction process happens mainly in the upper layer of the green space soil with a depth of 50-70 cm.

  15. Comparative study on sulphur reduction from heavy petroleum - Solvent extraction and microwave irradiation approach

    Directory of Open Access Journals (Sweden)

    Abdullahi Dyadya Mohammed, Abubakar Garba Isah, Musa Umaru, Shehu Ahmed, Yababa Nma Abdullahi

    2012-01-01

    Full Text Available Sulphur- containing compounds in heavy crude oils are undesirable in refining process as they affect the quality of the final product, cause catalyst poisoning and deactivation in catalytic converters as well as causing corrosion problems in oil pipelines, pumps and refining equipment aside environmental pollution from their combustion and high processing cost. Sulphur reduction has being studied using microwave irradiation set at 300W for 10 and 15minutes and oxidative- solvent extraction method using n- heptane and methanol by 1:1, 1:2 and 1:3 crude- solvent ratios after being oxidized with hydrogen peroxide, H2O2 oxidants. Percentage sulphur removal with n- heptane solvent by 1:1 and 1:2 are 81.73 and 85.47%; but extraction using methanol by different observed ratios gave less sulphur reduction. Indeed when microwave irradiated at 300W for 10 and 15minutes, 53.68 and 78.45% reduction were achieved. This indicates that microwave irradiation had caused oxidation by air in the oven cavity and results to formation of alkyl radicals and sulphoxide from sulphur compound in the petroleum. The prevailing sulphur found in the crude going by FT-IR results is sulphides which oxidized to sulphoxide or sulphones. It is clear that sulphur extraction with heptane is more efficient than microwave irradiation but economically due to demands for solvent and its industrial usage microwave irradiation can serve as alternative substitute for sulphur reduction in petroleum. Sulphur reduction by microwave radiation should be up- scaled from laboratory to a pilot plant without involving extraction column in the refining.

  16. Moessbauer study of carbon coated iron magnetic nanoparticles produced by simultaneous reduction/pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Mendonca, Fernanda G. [Universidade Federal de Minas Gerais, Departamento de Quimica - ICEx (Brazil); Ardisson, Jose D. [CDTN, Laboratorio de Fisica Aplicada, Centro de Desenvolvimento de Tecnologia Nuclear (Brazil); Rosmaninho, Marcelo G.; Lago, Rochel M.; Tristao, Juliana C., E-mail: juliana@ufv.br [Universidade Federal de Minas Gerais, Departamento de Quimica - ICEx (Brazil)

    2011-11-15

    Magnetic iron nanoparticles immersed in a carbon matrix were produced by a combined process of controlled dispersion of Fe{sup 3 + } ions in sucrose, thermal decomposition with simultaneous reduction of iron cores and the formation of the porous carbonaceous matrix. The materials were prepared with iron contents of 1, 4 and 8 in %wt in sucrose and heated at 400, 600 and 800 Degree-Sign . The samples were analyzed by XRD, Moessbauer spectroscopy, magnetization measurements, TG, SEM and TEM. The materials prepared at 400 Degree-Sign are composed essentially of Fe{sub 3}O{sub 4} particles and carbon, while treatments at higher temperatures, e.g. 600 and 800 Degree-Sign produced as main phases Fe{sup 0} and Fe{sub 3}C. The Moessbauer spectra of samples heated at 400 Degree-Sign showed two sextets characteristic of a magnetite phase and other contributions compatible with Fe{sup 3 + } and Fe{sup 2 + } phases in a carbonaceous matrix. Samples treated at temperatures above 600 Degree-Sign showed the presence of metallic iron with concentrations between 16-43%. The samples heated at 800 Degree-Sign produced higher amounts of Fe{sub 3}C (between 20% and 58%). SEM showed for the iron 8% sample treated at 600-800 Degree-Sign C particle sizes smaller than 50 nm. Due to the presence of Fe{sup 0} particles in the carbonaceous porous matrix the materials have great potential for application as magnetic adsorbents.

  17. Experimental Study on Tsunami Risk Reduction on Coastal Building Fronted by Sea Wall

    OpenAIRE

    Rahman, Sadia; Akib, Shatirah; M.T.R. Khan; Shirazi, S.M.

    2014-01-01

    This experimental study was conducted to idealize the efficacy of sea wall in controlling the tsunami forces on onshore structures. Different types of sea walls were placed in front of the building model. The tsunami forces and the wave heights were measured with and without the sea wall conditions. Types of sea wall, wall height, and wall positions were varied simultaneously to quantify the force reductions. Maximum of 41% forces was reduced by higher sea wall, positioned closer proximity to...

  18. Linear sweep voltametry studies on oxygen reduction of some oxides in alkaline electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Ananth, M.V. [Ni-MH Section, Electrochemical Power Sources Division, Central Electrochemical Research Institute, Karaikudi, 630 006 Tamil Nadu (India); Giridhar, V.V. [Electrodics and Electrocatalysis (EEC) Division, Central Electrochemical Research Institute, Karaikudi, 630 006 Tamil Nadu (India); Renuga, K. [Department of Chemistry, Thiagarajar College, Madurai 625 009 (India)

    2009-01-15

    The study uses linear sweep voltametry (LSV) to observe the efficiency of oxygen reduction on some oxides and their mixtures in 6 M KOH at 25 C. The investigated materials are Ag{sub 2}O, MnO{sub 2}, Sm{sub 2}O{sub 3}, Dy{sub 2}O{sub 3} and NdO{sub 2}. The electrocatalytic oxygen reduction reactions (ORR) on Teflon-bonded, oxide + graphite electrodes are studied. The oxygen reduction potentials for electrodes containing these materials as catalyst are seen as -60.67, -270.31, -111, -159.58 and -130.24 mV, respectively. Mixture combinations of these oxides give a higher ORR peak current thereby showing evidence of synergetic effect. Air-MH cells using some of the above investigated oxides as catalyst for air electrode are constructed and studied. Best performance is obtained with silver oxide. The LSV findings are in accordance with air-MH cell charge/discharge experiments and for best performance prefer shift of the ORR onset potential to more positive positions. (author)

  19. Comparative Study of Soluble Sulfate Reduction by Bacterial Consortia from Varied Regions of India

    Directory of Open Access Journals (Sweden)

    Poonam Nasipuri

    2010-01-01

    Full Text Available Soluble sulfate contamination in water is observed due to various industrial activities. Chemical means of reduction are available yet the biological approach is the preferred one. Problem statement: The problem addressed in this study was the isolation of efficient sulfate reducing bacterial consortia for bioremediation of soluble sulfate from mining effluent. Approach: The culture based method using the DSMZ specific media were used for isolation of sulfate reducing bacterial consortia. Their reduction efficiency was measured spectrophotometrically following growth under varied temperature and pH in specified media as well as in effluent water. The microbial consortia were analyzed at the 16SrDNA level to identify the members. The completeness as well as richness of the study was analyzed using OTU saturation curve, Shannon diversity index and equitability index. Results: All the eight consortia were able to tolerate vide range of pH (6-9 and temperature (20-40°C. They could reduce 63-99% of soluble sulfate (~2000 ppm in 48 h. Conclusion: This study reported about the enrichment of few of the most efficient anaerobic microbial consortia that could be employed for environmental soluble sulfate reduction under diverse pH and temperature conditions.

  20. The influence of Kinesiology Taping on the reduction of lymphoedema among women after mastectomy - preliminary study.

    Science.gov (United States)

    Pop, Teresa Bronisława; Karczmarek-Borowska, Bożenna; Tymczak, Monika; Hałas, Ireneusz; Banaś, Joanna

    2014-01-01

    Kinesiology Taping is a method that assists healing processes and improves the physical efficiency. The aim of the study was to assess the influence of Kinesiology Taping on the lymphoedema reduction among women after mastectomy. The subject of the research included 44 women underwent single mastectomy along with the removal of lymph nodes. The examination was carried out from the 4(th) of January to the 4(th) of February, 2013. The traditional taping method was implemented among 22 women, whereas the own taping method was used among the other 22 women. The therapy took 21 days, during which the tapes were applied three times every 7 days. The measurements were made before every application and at the end of the therapy. In the study, a questionnaire was used and it included questions concerning basic demographic, epidemiological data as well as the evaluation of the therapy effectiveness. The linear measurements of the upper limbs, the measurements of the range of joints' motion in the upper limb were taken as well as grip strength was made. The reduction of the volume of lymphoedema of 55% was reported in the study group, whereas the oedema reduced by 27% in the clinical control one. In the reduction of lymphoedema, the greater effectiveness of the own taping method in comparison to the traditional one was reported. Kinesiology Taping exerted an influence on the improvement of the upper limb's joints movability and the grip strength.

  1. Transverse limb reduction defects after chorion villus sampling: a retrospective cohort study. GIDEF--Gruppo Italiano Diagnosi Embrio-Fetali.

    Science.gov (United States)

    Mastroiacovo, P; Tozzi, A E; Agosti, S; Bocchino, G; Bovicelli, L; Dalprà, L; Carbone, L D; Lituania, M; Luttichau, A; Mantegazza, F

    1993-11-01

    A retrospective cohort study was performed in five Italian obstetrical centres from 1984 to 1991 in order to verify the association between chorionic villus sampling (CVS) and transverse limb reduction defects (TLRDs). TLRD rates by period of gestation at CVS were calculated, and the study's results were compared with data from the general population. Of the 3430 pregnancies for which CVS was performed, 2759 had a known outcome. The overall rate for TLRDs was 1 in 1143 CVS pregnancies, four times higher than that of the general population in Italy (1 in 4458). The rate of TLRDs was 2.9/1000 for CVS performed at 9 weeks' gestation and 1.0/1000 for CVS at 10 weeks' gestation. A scalp defect was detected in a pregnancy in which CVS was performed at 10 weeks. A high proportion of pregnancies lost to follow-up and the poor quality of the data may have affected the results. Nevertheless, our results suggest an association between CVS carried out at less than 10 weeks' gestation and TLRDs which is consistent with the findings of other studies. CVS should not be prepared at less than 10 weeks' gestation until additional evidence is obtained.

  2. Smoking reduction and cessation reduce chronic cough in a general population: the Inter99 study

    DEFF Research Database (Denmark)

    Pisinger, Charlotta; Godtfredsen, Nina; Jørgensen, Torben

    2008-01-01

    Background: Chronic cough can be the first sign of chronic obstructive disease. A few, and mostly selected, studies exploring the effect of reduced daily tobacco consumption have shown a small effect on pulmonary symptoms. Aim: The aim of this study was to examine if smoking reduction (SR) (>= 50......% of daily tobacco consumption) or smoking cessation (SC) had an effect on chronic cough and phlegm. Methods: A total of 2408 daily smokers were included in a Danish population-based intervention study, Inter99. In the analyses, we included smokers with self-reported chronic cough or phlegm at baseline who...

  3. Study of Large-Scale Aluminium-Doped Zinc Oxide Ceramic Targets Prepared by Slip Casting

    Directory of Open Access Journals (Sweden)

    Ling-yun Han

    2016-01-01

    Full Text Available Aluminium-doped zinc oxide (AZO ceramic green compacts at a size of 170 × 340 × 17 mm have been prepared by slip casting. An AZO slurry with good fluidity and viscosity was obtained when 1.2 wt% of dispersant was added, which indicates that the slurry prepared with micrometre particles is more suitable for slip casting. The densification and electrical properties of the AZO targets prepared by particles with different sizes were investigated after sintering from 1380 to 1460°C. The results showed that the relative density of the AZO target prepared with 45 nm particles could reach nearly 98% at 1380°C; the resistivity of the AZO target prepared with nanometre particles could be as low as 1.6 × 10−3 Ω·cm at 1400°C; and the average transmittance of the AZO film prepared with nanometre particles could reach a maximum value of 93.73% in the visible region at 250 W. In this study, the correlation between the density, resistivity, and grain growth of AZO ceramic green compacts was studied.

  4. Genome-wide study of gene variants associated with differential cardiovascular event reduction by pravastatin therapy.

    Directory of Open Access Journals (Sweden)

    Dov Shiffman

    Full Text Available Statin therapy reduces the risk of coronary heart disease (CHD, however, the person-to-person variability in response to statin therapy is not well understood. We have investigated the effect of genetic variation on the reduction of CHD events by pravastatin. First, we conducted a genome-wide association study of 682 CHD cases from the Cholesterol and Recurrent Events (CARE trial and 383 CHD cases from the West of Scotland Coronary Prevention Study (WOSCOPS, two randomized, placebo-controlled studies of pravastatin. In a combined case-only analysis, 79 single nucleotide polymorphisms (SNPs were associated with differential CHD event reduction by pravastatin according to genotype (P<0.0001, and these SNPs were analyzed in a second stage that included cases as well as non-cases from CARE and WOSCOPS and patients from the PROspective Study of Pravastatin in the Elderly at Risk/PHArmacogenomic study of Statins in the Elderly at risk for cardiovascular disease (PROSPER/PHASE, a randomized placebo controlled study of pravastatin in the elderly. We found that one of these SNPs (rs13279522 was associated with differential CHD event reduction by pravastatin therapy in all 3 studies: P = 0.002 in CARE, P = 0.01 in WOSCOPS, P = 0.002 in PROSPER/PHASE. In a combined analysis of CARE, WOSCOPS, and PROSPER/PHASE, the hazard ratio for CHD when comparing pravastatin with placebo decreased by a factor of 0.63 (95% CI: 0.52 to 0.75 for each extra copy of the minor allele (P = 4.8 × 10(-7. This SNP is located in DnaJ homolog subfamily C member 5B (DNAJC5B and merits investigation in additional randomized studies of pravastatin and other statins.

  5. Preparation of low-platinum-content platinum-nickel, platinum-cobalt binary alloy and platinum-nickel-cobalt ternary alloy catalysts for oxygen reduction reaction in polymer electrolyte fuel cells

    Science.gov (United States)

    Li, Mu; Lei, Yanhua; Sheng, Nan; Ohtsuka, Toshiaki

    2015-10-01

    A series of low-platinum-content platinum-nickel (Pt-Ni), platinum-cobalt (Pt-Co) binary alloys and platinum-nickel-cobalt (Pt-Ni-Co) ternary alloys electrocatalysts were successfully prepared by a three-step process based on electrodeposition technique and studied as electrocatalysts for oxygen reduction reaction (ORR) in polymer-electrolyte fuel cells. Kinetics of ORR was studied in 0.5 M H2SO4 solution on the Pt-Ni, Pt-Co and Pt-Ni-Co alloys catalysts using rotating disk electrode technique. Both the series of Pt-Ni, Pt-Co binary alloys and the Pt-Ni-Co ternary alloys catalysts exhibited an obvious enhancement of ORR activity in comparison with pure Pt. The significant promotion of ORR activities of Pt-Ni and Pt-Co binary alloys was attributed to the enhancement of the first electron-transfer step, whereas, Pt-Ni-Co ternary alloys presented a more complicated mechanism during the electrocatalysis process but a much more efficient ORR activities than the binary alloys.

  6. A study on the indirect urea dosing method in the Selective Catalytic Reduction system

    Science.gov (United States)

    Brzeżański, M.; Sala, R.

    2016-09-01

    This article presents the results of studies on concept solution of dosing urea in a gas phase in a selective catalytic reduction system. The idea of the concept was to heat-up and evaporate the water urea solution before introducing it into the exhaust gas stream. The aim was to enhance the processes of urea converting into ammonia, what is the target reductant for nitrogen oxides treatment. The study was conducted on a medium-duty Euro 5 diesel engine with exhaust line consisting of DOC catalyst, DPF filter and an SCR system with a changeable setup allowing to dose the urea in liquid phase (regular solution) and to dose it in a gas phase (concept solution). The main criteria was to assess the effect of physical state of urea dosed on the NOx conversion ratio in the SCR catalyst. In order to compare both urea dosing methods a special test procedure was developed which consisted of six test steps covering a wide temperature range of exhaust gas generated at steady state engine operation condition. Tests were conducted for different urea dosing quantities defined by the a equivalence ratio. Based on the obtained results, a remarkable improvement in NOx reduction was found for gas urea application in comparison to the standard liquid urea dosing. Measured results indicate a high potential to increase an efficiency of the SCR catalyst by using a gas phase urea and provide the basis for further scientific research on this type of concept.

  7. A kinetic study of copper(II) oxide powder reduction with hydrogen, based on thermogravimetry

    Energy Technology Data Exchange (ETDEWEB)

    Jelic, Dijana [Faculty of Medicine, Departmet of Pharmacy - Chair of Physical Chemistry, University of Banja Luka, Banja Luka, Bosnia and Herzegovina (Bosnia and Herzegowina); Tomic-Tucakovic, Biljana [Institute of General and Physical Chemistry, Studentski trg 12, 11158 Belgrade (Serbia); Mentus, Slavko, E-mail: slavko@ffh.bg.ac.rs [University of Belgrade, Faculty of Physical Chemistry, Studentski trg 12, 11185 Belgrade (Serbia)

    2011-07-10

    Highlights: {yields} The reduction of CuO by hydrogen was studied by thermogravimetry. {yields} The particle size of the samples varied inside the submicron range. {yields} The experimental data were fitted by means of a nucleation-growth model. {yields} The particle size influenced the kinetic parameters but not the reaction model. - Abstract: The reduction of powdery copper(II) oxide was carried out in a stream of gaseous mixture 25% H{sub 2} + Ar, and followed by thermogravimetry. The two samples of different history were studied: the commercial one, and that synthesized by citrate gel combustion method. The characterization of the starting materials, based on X-ray diffractometry and scanning electron microscopy, indicated equal crystal structure, but different particle size and morphology. The particle size and shape of the metallic particles obtained upon the reduction were observed by means of electron microscope. By a nonlinear regression analysis by means of a software Kinetics05, the experimental data were fitted with the nucleation-growth kinetic model, and the corresponding kinetic parameters were determined.

  8. The Effect of Reduction Mammaplasty on the Vertebral Column: A Radiologic Study

    Directory of Open Access Journals (Sweden)

    Onder Karaaslan

    2013-01-01

    Full Text Available Some studies emphasized that anatomic mechanisms of vertebral aberrations could be associated with large breasts. The effect of mammaplasty operation on the vertebral column and body posture seems to be beneficial; in this trial, it was planned to investigate the objective radiologic effect of reduction mammaplasty on the posture of the vertebral column in a group of patients operated due to the large breasts. Thirty-four white women with large breasts were enrolled in this study. The patients were divided into three groups according to their breast cup sizes. Anteroposterior and lateral radiographs of the lumbosacral and thoracic spine were taken at baseline preoperatively, and the same radiographic images were taken in an average of 12 months later than the reduction mammaplasty operation. All were evaluated and compared for thoracic kyphosis angle and lumbar lordosis angle both preoperatively and postoperatively. The mean thoracic kyphosis angle was 40,53 preoperatively and 39,38 postoperatively. However, there was no statistically significant difference between the preoperative and postoperative measurements in all groups (P>0,05. The mean lumbar lordosis angle was 54,71 preoperatively and 53,18 postoperatively. Regarding the preoperative and postoperative measurements of lumbar lordosis angles, no statistically significant difference was found between the groups (P>0,05. Although breast size may be an important factor that affects body posture, reduction mammaplasty operations have little or no radiologic effect on the vertebral column.

  9. The effect of reduction mammaplasty on the vertebral column: a radiologic study.

    Science.gov (United States)

    Karaaslan, Onder; Demirkiran, H Gokhan; Silistreli, Ozlem; Sonmez, Erhan; Bedir, Yagmur Kaan; Can, Melih; Caliskan, Gorkem; Aslan, Cem; Oral, Meltem Ayhan; Kankaya, Yuksel

    2013-01-01

    Some studies emphasized that anatomic mechanisms of vertebral aberrations could be associated with large breasts. The effect of mammaplasty operation on the vertebral column and body posture seems to be beneficial; in this trial, it was planned to investigate the objective radiologic effect of reduction mammaplasty on the posture of the vertebral column in a group of patients operated due to the large breasts. Thirty-four white women with large breasts were enrolled in this study. The patients were divided into three groups according to their breast cup sizes. Anteroposterior and lateral radiographs of the lumbosacral and thoracic spine were taken at baseline preoperatively, and the same radiographic images were taken in an average of 12 months later than the reduction mammaplasty operation. All were evaluated and compared for thoracic kyphosis angle and lumbar lordosis angle both preoperatively and postoperatively. The mean thoracic kyphosis angle was 40,53 preoperatively and 39,38 postoperatively. However, there was no statistically significant difference between the preoperative and postoperative measurements in all groups (P > 0,05). The mean lumbar lordosis angle was 54,71 preoperatively and 53,18 postoperatively. Regarding the preoperative and postoperative measurements of lumbar lordosis angles, no statistically significant difference was found between the groups (P > 0,05). Although breast size may be an important factor that affects body posture, reduction mammaplasty operations have little or no radiologic effect on the vertebral column.

  10. The reduction of biological production induced by mesoscale mixing: a modelling study in the Benguela upwelling

    CERN Document Server

    Hernández-Carrasco, Ismael; Hernández-García, Emilio; Garçon, Veronique; López, Cristóbal

    2013-01-01

    Recent studies, both based on remote sensed data and coupled models, showed a reduction of biological productivity due to vigorous horizontal mixing in upwelling systems. In order to better understand this phenomenon, we have considered a system of oceanic flow in the Benguela area coupled with a simple biogeochemical model of Nutrient-Phyto-Zooplankton (NPZ) type. For the flow three different surface velocity fields are considered: one derived from satellite altimetry data, and the other two from a regional numerical model at two different spatial resolutions. We computed horizontal particle dispersion in terms of Lyapunov Exponents, and analyzed their correlations with phytoplankton concentrations. Our modelling approach confirms that in the south Benguela, there is a reduction of biological activity when stirring is increased. Two-dimensional offshore advection seems to be the dominant process involved. In the northern area, other factors not taken into account in our simulation are influencing the ecosyst...

  11. Challenges to disaster risk reduction: A study of stakeholders’ perspectives in Imizamo Yethu, South Africa

    Directory of Open Access Journals (Sweden)

    Ann-Sofie Roth

    2011-04-01

    Full Text Available South Africa is a complex and dynamic society, with overwhelming and increasing problems with disaster risk in the vulnerable urban communities in and around its rapidly growing metropolitan centres. The purpose of this study is to improve the understanding of the challenges for disaster risk reduction in such communities. It focuses on the case of Imizamo Yethu, in the Western Cape, in order to build theory that is grounded in the empirical realities of stakeholders involved in disaster risk reduction there. The result points towards five interrelated key challenges, which must be concurrently addressed through large-scale development efforts. Without such investments, it is unlikely that disaster risks can be reduced to tolerable levels.

  12. Smokeless tobacco reduction: preliminary study of tobacco-free snuff versus no snuff.

    Science.gov (United States)

    Hatsukami, Dorothy K; Ebbert, Jon O; Edmonds, Amanda; Li, Casey; Lin, Haiying; Le, Chap; Hecht, Stephen S

    2008-01-01

    This preliminary study examined the effects of tobacco-free snuff (intervention, n = 52) compared with no snuff (control, n = 54) for reducing tobacco use among smokeless tobacco (ST) users not interested in quitting. Both groups received behavioral instructions, and intervention subjects received tobacco-free snuff for 8 weeks. Participants were required to reduce their intake by 50% during the first 4 weeks and by 75% during the subsequent 4 weeks. Follow-up occurred at 12 weeks. Significant reductions were observed from baseline to week 8 (end of treatment) for both treatment groups in the amount of ST use (tins/week and dips/day, psnuff could potentially reduce risk for ST-related disease beyond that achieved with no snuff by increasing the number of patients who achieve significant reductions in carcinogen exposure and, more important, by facilitating tobacco abstinence by increasing quit attempts and abstinence duration.

  13. Study of reduction of chromium (VI by calcium polysulfide using spectrophotometric method

    Directory of Open Access Journals (Sweden)

    Batukhan Tatykaev

    2013-05-01

    Full Text Available The paper presents  the results of the study on reduction  of  Cr2O72-   to   Cr3 +  by aqueous solution of calcium polysulfide  using spectrophotometric method. Concentrations  of Cr (VI were determined on the basis of the absorption spectrum at the wavelength range 350 - 372 nm. The change of the concentration of Cr (VI during on reduction by calcium polysulfide has been shown.  The influence of pH on the rate of reducing of Cr (VI to Cr (III was considered: the rate of reducing of hexavalent chromium decreases with increasing pH. The data obtained show that recycling Cr (VI in industrial scale potentially effective at  the pH = 5.

  14. COMPARATIVE STUDY OF DIMENSIONALITY REDUCTION TECHNIQUES USING PCA AND LDA FOR CONTENT BASED IMAGE RETRIEVAL

    Directory of Open Access Journals (Sweden)

    Shereena V. B

    2015-04-01

    Full Text Available The aim of this paper is to present a comparative study of two linear dimension reduction methods namely PCA (Principal Component Analysis and LDA (Linear Discriminant Analysis. The main idea of PCA is to transform the high dimensional input space onto the feature space where the maximal variance is displayed. The feature selection in traditional LDA is obtained by maximizing the difference between classes and minimizing the distance within classes. PCA finds the axes with maximum variance for the whole data set where LDA tries to find the axes for best class seperability. The proposed method is experimented over a general image database using Matlab. The performance of these systems has been evaluated by Precision and Recall measures. Experimental results show that PCA based dimension reduction method gives the better performance in terms of higher precision and recall values with lesser computational complexity than the LDA based method.

  15. Enhanced magnetic properties of NiO powders by the mechanical activation of aluminothermic reduction of NiO prepared by a ball milling process

    Science.gov (United States)

    Padhan, Aneeta Manjari; Ravikumar, P.; Saravanan, P.; Alagarsamy, Perumal

    2016-11-01

    We report the effect of mechanical activation on NiO-Al (x wt%) reduction reaction and resulting structural and magnetic properties by carrying out high-energy planetary ball milling. The pure NiO (un-milled) and milled NiO-Al (x≤2.5) powders exhibit face centered cubic structure, but the antiferromagnetic nature of pure NiO powder shows significant room temperature ferromagnetism with moderate moment and coercivity after milling due to non-stoichiometry in NiO caused by the defects, size reduction and oxidation of Ni. On the other hand, the addition of Al between 2.5 and 10% in NiO forms solid solution of NiO-Al with considerable reduction in the moment due to the atomic disorder. With increasing Al above 10%, NiO reduction reaction progresses gradually and as a result, the average magnetization increases from 0.57 to 4.3 emu/g with increasing Al up to 25%. A maximum of 91% reduction was observed for NiO-Al (40%) powders in 30 h of milling with a large increase in magnetization (~24 emu/g) along with the development of α-Al2O3. Thermomagnetization data reveal the presence of mixed magnetic phases in milled NiO powders and the component of induced ferromagnetic phase fades out with increasing Al due to the formation of Ni from the NiO-Al reduction reaction. The changes in the structural and magnetic properties are discussed on the basis of mechanical activation on the reduction of NiO by Al. The controlled reduction reaction with different Al content in NiO-Al is encouraging for the applications in catalysis and process of ore reduction.

  16. An experimental and ab initio study on the abiotic reduction of uranyl by ferrous iron

    Science.gov (United States)

    Taylor, S. D.; Marcano, M. C.; Rosso, K. M.; Becker, U.

    2015-05-01

    It is important to understand the mechanisms controlling the removal of uranyl from solution from an environmental standpoint, particularly whether soluble Fe(II) is capable of reducing soluble U(VI) to insoluble U(IV). Experiments were performed to shed light into discrepancies of recent studies about precipitation of U-containing solids without changing oxidation states versus precipitation/reduction reactions, especially with respect to the kinetics of these reactions. To understand the atomistic mechanisms, thermodynamics, and kinetics of these redox processes, ab initio electron transfer (ET) calculations, using Marcus theory, were applied to study the reduction of U(VI)aq to U(V)aq by Fe(II)aq (the first rate-limiting ET-step). Outer-sphere (OS) and inner-sphere (IS) Fe-U complexes were modeled to represent simple species within a homogeneous environment through which ET could occur. Experiments on the chemical reduction were performed by reacting 1 mM Fe(II)aq at pH 7.2 with high (i.e., 0.16 mM) and lower (i.e., 0.02 mM) concentrations of U(VI)aq. At higher U concentration, a rapid decrease in U(VI)aq was observed within the first hour of reaction. XRD and XPS analyses of the precipitates confirmed the presence of (meta)schoepite phases, where up to ∼25% of the original U was reduced to U4+ and/or U5+-containing phases. In contrast, at 0.02 mM U, the U(VI)aq concentration remained fairly constant for the first 3 h of reaction and only then began to decrease due to slower precipitation kinetics. XPS spectra confirm the partial chemical reduction U associated with the precipitate (up to ∼30%). Thermodynamic calculations support that the reduction of U(VI)aq to U(IV)aq by Fe(II)aq is energetically unfavorable. The batch experiments in this study show U(VI) is removed from solution by precipitation and that transitioning to a heterogeneous system in turn enables the solid U phase to be partially reduced. Ab initio ET calculations revealed that OS ET is

  17. Intentional weight loss and dose reductions of anti-diabetic medications--a retrospective cohort study.

    Directory of Open Access Journals (Sweden)

    Anita Ashok Kumar

    Full Text Available BACKGROUND AND AIM: Intentional weight loss, primarily by improving insulin resistance, is known to decrease the need for anti-diabetic medications. In this study, we assess the magnitude of weight loss that resulted in dose reductions or discontinuation of anti-diabetic medications in overweight or obese patients with type 2 diabetes (DM undergoing weight loss treatment. METHODS: Case records of 50 overweight or obese patients with DM who successfully decreased dosage or discontinued diabetes medications after losing weight via attendance at two University-based, outpatient weight management centers were analyzed. Follow-up visits, weight reduction interventions, and decisions for dose reductions or discontinuation of medications were individualized to patient needs by the treating physician. RESULTS: Mean starting BMI was 35 kg/m(2, mean age 53.4 years, and 58% were male. All 50 used at least one anti-diabetic medication (30 metformin, 39 sulfonylureas, 31 insulin, 21 sitagliptin to manage blood sugar. Mean duration of follow-up was 30.2 months. Mean weight loss was 10.8 ± 4.1 kgs (11.1% of initial body weight ± 4.7%. 22/50 patients (44% discontinued anti-diabetes medications (14 sulfonylureas [36%], 7 insulin [23%], 4 sitagliptin [19%]. The mean percentage weight loss achieved at the point of successful discontinuation of medication was 11.2% ± 3.5% (14% for sulphonylureas, 11% for insulin, and 7.1% for sitagliptin. Mean percentage weight loss of 5.6% ± 2.8% (5.1% for sulphonylureas, 4.3% for insulin, and 7.1% for sitagliptin was required for initial dose reduction. For every 5% weight loss, predicted dose reductions were sulphonylureas, 39%; insulin, 42%; and any anti-diabetic medications, 49%. CONCLUSION: Among overweight or obese patients with type 2 diabetes, intentional weight loss of 7-14% was typically required for full discontinuation of at least one anti-diabetic medication. Discontinuation of insulin was achieved at a mean

  18. Platinum nanoparticles on carbon-nanotube support prepared by room-temperature reduction with H2 in ethylene glycol/water mixed solvent as catalysts for polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Zheng, Yuying; Dou, Zhengjie; Fang, Yanxiong; Li, Muwu; Wu, Xin; Zeng, Jianhuang; Hou, Zhaohui; Liao, Shijun

    2016-02-01

    Polyol approach is commonly used in synthesizing Pt nanoparticles in polymer electrolyte membrane fuel cells. However, the application of this process consumes a great deal of time and energy, as the reduction of precursors requires elevated temperatures and several hours. Moreover, the ethylene glycol and its oxidizing products bound to Pt are difficult to remove. In this work, we utilize the advantages of ethylene glycol and prepare Pt nanoparticles through a room-temperature hydrogen gas reduction in an ethylene glycol/water mixed solvent, which is followed by subsequent harvesting by carbon nanotubes as electrocatalysts. This method is simple, facile, and time-efficient, as the entire room-temperature reduction process is completed in a few minutes. As the solvent changes from water to an ethylene glycol/water mix, the size of Pt nanoparticles varies from 10 to 3 nm and their shape transitions from polyhedral to spherical. Pt nanoparticles prepared in a 1:1 volume ratio mixture of ethylene glycol/water are uniformly dispersed with an average size of ∼3 nm. The optimized carbon nanotube-supported Pt electrocatalyst exhibits excellent methanol oxidation and oxygen reduction activities. This work demonstrates the potential use of mixed solvents as an approach in materials synthesis.

  19. Comparative studies of salinomycin-loaded nanoparticles prepared by nanoprecipitation and single emulsion method

    Science.gov (United States)

    Wang, Qin; Wu, Puyuan; Ren, Wei; Xin, Kai; Yang, Yang; Xie, Chen; Yang, Chenchen; Liu, Qin; Yu, Lixia; Jiang, Xiqun; Liu, Baorui; Li, Rutain; Wang, Lifeng

    2014-07-01

    To establish a satisfactory delivery system for the delivery of salinomycin (Sal), a novel, selective cancer stem cell inhibitor with prominent toxicity, gelatinase-responsive core-shell nanoparticles (NPs), were prepared by nanoprecipitation method (NR-NPs) and single emulsion method (SE-NPs). The gelatinase-responsive copolymer was prepared by carboxylation and double amination method. We studied the stability of NPs prepared by nanoprecipitation method with different proportions of F68 in aqueous phase to determine the best proportion used in our study. Then, the NPs were prepared by nanoprecipitation method with the best proportion of F68 and single emulsion method, and their physiochemical traits including morphology, particle size, zeta potential, drug loading content, stability, and in vitro release profiles were studied. The SE-NPs showed significant differences in particle size, drug loading content, stability, and in vitro release profiles compared to NR-NPs. The SE-NPs presented higher drug entrapment efficiency and superior stability than the NR-NPs. The drug release rate of SE-NPs was more sustainable than that of the NR-NPs, and in vivo experiment indicated that NPs could prominently reduce the toxicity of Sal. Our study demonstrates that the SE-NPs could be a satisfactory method for the preparation of gelatinase-responsive NPs for intelligent delivery of Sal.

  20. Determinants of higher education students’ willingness to pay for violent crime reduction: a contingent valuation study

    OpenAIRE

    Mafalda Soeiro; Aurora A.C. Teixeira

    2010-01-01

    By eliciting an individual’s Willingness to Pay (WTP) for a reduction in crime risks, the contingent valuation method is one of the most solid methodologies in use to estimate the intangible costs of crime. However, very few studies have applied contingent valuation methods to random samples of the population located in high crime rate areas. This study is, to the best of our knowledge, the first attempt to apply the contingent valuation method to estimate how much a specific group of society...

  1. DRIFT study of manganese/ titania-based catalysts for low-temperature selective catalytic reduction of NO with NH3.

    Science.gov (United States)

    Wu, Zhongbiao; Jiang, Boqiong; Liu, Yue; Wang, Haiqiang; Jin, Ruiben

    2007-08-15

    Manganese oxides and iron-manganese oxides supported on TiO2 were prepared by the sol-gel method and used for low-temperature selective catalytic reduction (SCR) of NO with NH3. Base on the previous study, Mn(0.4)/ TiO2 and Fe(0.1)-Mn(0.4)/TiO2 were then selected to carry out the in situ diffuse reflectance infrared transform spectroscopy (DRIFT) investigation for revealing the reaction mechanism. The DRIFT spectroscopy for the adsorption of NH3 indicated the presence of coordinated NH3 and NH4+ on both of the two catalysts. When NO was introduced, the coordinated NH3 on the catalyst surface was consumed rapidly, indicating these species could react with NO effectively. When NH3 was introduced into the sample preadsorbed with NO + O2, SCR reaction would not proceed on Mn(0.4)/TiO2. However, for Fe(0.1)-Mn(0.4)/ TiO2 the bands due to coordinated NH3 on Fe2O3 were formed. Simultaneously, the bidentate nitrates were transformed to monodentate nitrates and NH4+ was detected. And NO2 from the oxidation of NO on catalyst could react with NH4+ leading to the reduction of NO. Therefore, it was suggested that the SCR reaction on Fe(0.1)-Mn(0.4)/TiO2 could also take place in a different way from the reactions on Mn(0.4)/TiO2 proposed by other researchers. Furthermore, the SCR reaction steps for these two kinds of catalysts were proposed.

  2. Lifestyle changes and reduction of colon cancer incidence in Europe : A scenario study of physical activity promotion and weight reduction

    NARCIS (Netherlands)

    de Vries, E.; Soerjomataram, I.; Lemmens, V. E. P. P.; Coebergh, J. W. W.; Barendregt, J. J.; Oenema, A.; Moller, H.; Brenner, H.; Renehan, Andrew G.

    2010-01-01

    Background: Across Europe, there are over 300,000 new cases of colorectal cancer annually. Major risk factors include excess body weight (usually expressed by a high body mass index, BMI) and physical inactivity (PA). In this study we modelled the potential long-term effects on colon cancer incidenc

  3. Lifestyle changes and reduction of colon cancer incidence in Europe : A scenario study of physical activity promotion and weight reduction

    NARCIS (Netherlands)

    de Vries, E.; Soerjomataram, I.; Lemmens, V. E. P. P.; Coebergh, J. W. W.; Barendregt, J. J.; Oenema, A.; Moller, H.; Brenner, H.; Renehan, Andrew G.

    Background: Across Europe, there are over 300,000 new cases of colorectal cancer annually. Major risk factors include excess body weight (usually expressed by a high body mass index, BMI) and physical inactivity (PA). In this study we modelled the potential long-term effects on colon cancer

  4. Two-electron reduction of nitroaromatic compounds by flavin mononucleotide. DFT computational study

    Directory of Open Access Journals (Sweden)

    Liudmyla K. Sviatenko

    2016-08-01

    Full Text Available The mechanism for reduction of nitroaromatic compounds by flavin mononucleotide (FMN was examined at MPWB1K/tzvp level. The solvent effects were calculated using a PCM(Pauling and SMD(Pauling solvation models for ions and neutral molecules, respectively. Calculated thermodynamics of the reduction of nitro group to nitroso group suggests consequtive four-steps’ process (electron–proton–electron–proton transfer where the first proton comes from solution, while the second one – from FMN. Water molecule releases during fourth step of the process. Electron attachment to nitrocompound and electron lose by reduced FMN facilitate the breaking of N–O bond and proton release, respectively. Calculations show that reduction of nitro group to nitroso group in studied nitrocompounds is a thermodynamically feasible with 56–59 kcal/mol Gibbs free energy release. The most easy electron transfer proceeds for TNT (2,4,6-trinitrotoluene and NTO (5-nitro-2,4-dihydro-3H-1,2,4-triazol-3-one. While the most energy release occurs during proton transfer in case of ANTA (5-amino-3-nitro-1H-1,2,4-triazole.

  5. Experimental Study on Tsunami Risk Reduction on Coastal Building Fronted by Sea Wall

    Directory of Open Access Journals (Sweden)

    Sadia Rahman

    2014-01-01

    Full Text Available This experimental study was conducted to idealize the efficacy of sea wall in controlling the tsunami forces on onshore structures. Different types of sea walls were placed in front of the building model. The tsunami forces and the wave heights were measured with and without the sea wall conditions. Types of sea wall, wall height, and wall positions were varied simultaneously to quantify the force reductions. Maximum of 41% forces was reduced by higher sea wall, positioned closer proximity to the model whereas this reduction was about 27% when the wall height was half of the high wall. Experimental investigations revealed that wall with adequate height and placed closer to the structures enables a satisfactory predictor of the force reduction on onshore structures. Another set of tests were performed with perforated wall placing near the building model. Less construction cost makes the provision of perforated sea wall interesting. The overall results showed that the efficacy of perforated wall is almost similar to solid wall. Hence, it can be efficiently used instead of solid wall. Moreover, overtopped water that is stuck behind the wall is readily gone back to the sea through perforations releasing additional forces on the nearby structures.

  6. Study of Electrochemical Reduction of CO2 for Future Use in Secondary Microbial Electrochemical Technologies.

    Science.gov (United States)

    Gimkiewicz, Carla; Hegner, Richard; Gutensohn, Mareike F; Koch, Christin; Harnisch, Falk

    2017-03-09

    The fluctuation and decentralization of renewable energy have triggered the search for respective energy storage and utilization. At the same time, a sustainable bioeconomy calls for the exploitation of CO2 as feedstock. Secondary microbial electrochemical technologies (METs) allow both challenges to be tackled because the electrochemical reduction of CO2 can be coupled with microbial synthesis. Because this combination creates special challenges, the electrochemical reduction of CO2 was investigated under conditions allowing microbial conversions, that is, for their future use in secondary METs. A reproducible electrodeposition procedure of In on a graphite backbone allowed a systematic study of formate production from CO2 with a high number of replicates. Coulomb efficiencies and formate production rates of up to 64.6±6.8 % and 0.013±0.002 mmolformate  h(-1)  cm(-2) , respectively, were achieved. Electrode redeposition, reusability, and long-term performance were investigated. Furthermore, the effect of components used in microbial media, that is, yeast extract, trace elements, and phosphate salts, on the electrode performance was addressed. The results demonstrate that the integration of electrochemical reduction of CO2 in secondary METs can become technologically relevant.

  7. Raman spectroscopic study of phosphogypsum thermal reduction with the carbonaceous material.

    Science.gov (United States)

    Msila, Xolani; Barnard, Werner; Billing, Dave G

    2015-10-05

    Elemental sulphur (S) can be produced from hydrogen sulphide (H2S) in a PiPco or Iron process. In turn H2S can be stripped with carbon dioxide (CO2) from calcium sulphide (CaS) obtained from the thermal reduction of phosphogypsum with carbon. The reaction pathway for the thermal reduction of the phosphogypsum with graphite was studied using thermogravimetric analysis and in situ Raman spectroscopy. The dehydration of the phosphogypsum to anhydrite was completed at about 142 °C. The dehydration was followed by the formation of the intermediate compound at about 860 °C which is characterised by a mass loss of about 11%. The intermediate compound, identified using the in situ Raman spectroscopy to be a dehydrated orschallite-type compound (Ca3[SO4][SO3]2), converted to CaS at about 935 °C. The presence of the metal impurities in the phosphogypsum: Ni(2+)(4 mg kg(-1)); Co(2+)(2 mg kg(-1)); Mn(2+)(5 mg kg(-1)); Cu(2+)(14 mg kg(-1)); Fe(2+)(200 mg kg(-1)) and Mg(2+)(300 mg kg(-1)) showed no influence the onset temperature for the reduction reaction.

  8. Concave Cu-Pd bimetallic nanocrystals: Ligand-based Co-reduction and mechanistic study

    Institute of Scientific and Technical Information of China (English)

    Lan Zhang[1; Hongyang Su[1; Mei Sun[1; Youcheng Wang[1; Wenlong Wu[1; Taekyung Yu[2; Jie Zeng[1

    2015-01-01

    The synthesis of highly uniform alloy nanocrystals with a concave feature is desirable for applications in catalysis but is an arduous task. This article proposes an initiative protocol for the fabrication of novel Cu-Pd alloy nanocrystals, wherein the volume of decylamine (DA) in the reaction system was found to greatly influence the formation of different morphologies, including the tetrahedron (TH), concave tetrahedron (CTH), rhombohedral-tetrapod (RTP), and tetrapod (TP). The alloy structure of the products arises from the coordination interaction between the DA and metal ions, which affects the reduction potential of Cu and Pd species, and thus yields co-reduction. Other reaction parameters, such as the type of ligand, amount of reductant, and temperature, were also altered to study the growth mechanism, yielding consistent conclusions in the diffusion-controlled regime. As a catalyst, 48-nm Cu-Pd concave tetrahedral nanocrystals were highly active for the hydrogenation of 3-nitrostyrene and exhibited 〉99.9% chemoselectivity to C=C instead of-NO2.

  9. NiO/YSZ Reduction for SOFC/SOEC Studied In Situ by Environmental Transmission Electron Microscopy

    DEFF Research Database (Denmark)

    Simonsen, Søren Bredmose; Agersted, Karsten; Hansen, Karin Vels

    2014-01-01

    SOFCs/SOECs are typically composed of ceramic materials, which are highly complex at the nano-scale. Scanning and transmission electron microscopy (SEM and TEM) are routinely applied for studying these nano-scaled structures post mortem, but only few SOFC/SOEC studies have applied environmental TEM...... the reduction of NiO/YSZ is slower, which indicates that the presence of YSZ inhibits the reduction of NiO. In the presents in situ experiments the temperature dependent reduction profile are found similar for the both nano-scaled NiO and NiO/YSZ sample. The apparent inhibitive effect of YSZ on NiO reduction...

  10. Reduction of Carbon Dioxide by a Molybdenum-Containing Formate Dehydrogenase: A Kinetic and Mechanistic Study.

    Science.gov (United States)

    Maia, Luisa B; Fonseca, Luis; Moura, Isabel; Moura, José J G

    2016-07-20

    Carbon dioxide accumulation is a major concern for the ecosystems, but its abundance and low cost make it an interesting source for the production of chemical feedstocks and fuels. However, the thermodynamic and kinetic stability of the carbon dioxide molecule makes its activation a challenging task. Studying the chemistry used by nature to functionalize carbon dioxide should be helpful for the development of new efficient (bio)catalysts for atmospheric carbon dioxide utilization. In this work, the ability of Desulfovibrio desulfuricans formate dehydrogenase (Dd FDH) to reduce carbon dioxide was kinetically and mechanistically characterized. The Dd FDH is suggested to be purified in an inactive form that has to be activated through a reduction-dependent mechanism. A kinetic model of a hysteretic enzyme is proposed to interpret and predict the progress curves of the Dd FDH-catalyzed reactions (initial lag phase and subsequent faster phase). Once activated, Dd FDH is able to efficiently catalyze, not only the formate oxidation (kcat of 543 s(-1), Km of 57.1 μM), but also the carbon dioxide reduction (kcat of 46.6 s(-1), Km of 15.7 μM), in an overall reaction that is thermodynamically and kinetically reversible. Noteworthy, both Dd FDH-catalyzed formate oxidation and carbon dioxide reduction are completely inactivated by cyanide. Current FDH reaction mechanistic proposals are discussed and a different mechanism is here suggested: formate oxidation and carbon dioxide reduction are proposed to proceed through hydride transfer and the sulfo group of the oxidized and reduced molybdenum center, Mo(6+)═S and Mo(4+)-SH, are suggested to be the direct hydride acceptor and donor, respectively.

  11. A Quantitative Correlational Study of Teacher Preparation Program on Student Achievement

    Science.gov (United States)

    Dingman, Jacob Blackstone

    2010-01-01

    The purpose of this quantitative correlational study was to identify the relationship between the type of teacher preparation program and student performance on the seventh and eighth grade mathematics state assessments in rural school settings. The study included a survey of a convenience sample of 36 teachers from Colorado and Washington school…

  12. A case study exploring the current issues faced by diploma-prepared nurses.

    Science.gov (United States)

    Droskinis, Amy

    2013-01-01

    Nursing is a dynamic and rapidly progressing field. As the profession changes over time, it is vital to study how these transformations influence the workforce. In this study, the aim was to explore how diploma-prepared nurses are functioning in the acute care setting and how modifications in educational requirements and technological advancement have affected their nursing practice.

  13. Preliminary observation of self-reduction of Eu ions in α-Ca{sub 3}(PO{sub 4}){sub 2} phosphors prepared in air condition

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Chao [College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Zhu, Yangguang; Xu, Chuanyan [Suzhou Biomaterials and Advanced Manufacture Engineering Technology Research Center, Suzhou Dingan Technology Co., Ltd, Suzhou 215200 (China); Li, Yadong, E-mail: liyadong@suda.edu.cn [College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China)

    2016-11-01

    A series of Eu doped α-Ca{sub 3}(PO{sub 4}){sub 2} phosphors were synthesized by a high-temperature solid-state reaction in air atmosphere. The crystal structures, photoluminescence properties of the phosphors were systematically studied. The emission spectra showed a broad emission band centered at 492 nm attributed to the typical 4f{sup 6}5d{sup 1}→4f{sup 7} transition of Eu{sup 2+}ions, and several sharp peaks from 560 to 750 nm attributed to the 5D{sub 0}→7F{sub J}(J=0,1,2,3,4) transition of Eu{sup 3+}ions. The results, combined with the X-ray photoelectron spectroscopy measurements, demonstrate self-reduction of Eu{sup 3+}to Eu{sup 2+}occurred in α-Ca{sub 3}(PO{sub 4}){sub 2} matrix for the first time. This suggested that the Eu{sup 2+}ions in α-Ca{sub 3}(PO{sub 4}){sub 2}could serve as a spectroscopic probe to detect the content of α-Ca{sub 3}(PO{sub 4}){sub 2}in phase transition process.

  14. Preliminary observation of self-reduction of Eu ions in α-Ca3(PO4)2 phosphors prepared in air condition

    Science.gov (United States)

    Tong, Chao; Zhu, Yangguang; Xu, Chuanyan; Li, Yadong

    2016-11-01

    A series of Eu doped α-Ca3(PO4)2 phosphors were synthesized by a high-temperature solid-state reaction in air atmosphere. The crystal structures, photoluminescence properties of the phosphors were systematically studied. The emission spectra showed a broad emission band centered at 492 nm attributed to the typical 4f65d1→4f7 transition of Eu2+ions, and several sharp peaks from 560 to 750 nm attributed to the 5D0→7FJ(J=0,1,2,3,4) transition of Eu3+ions. The results, combined with the X-ray photoelectron spectroscopy measurements, demonstrate self-reduction of Eu3+to Eu2+occurred in α-Ca3(PO4)2 matrix for the first time. This suggested that the Eu2+ions in α-Ca3(PO4)2could serve as a spectroscopic probe to detect the content of α-Ca3(PO4)2in phase transition process.

  15. Designing, Prototyping and Evaluating Digital Mindfulness Applications: A Case Study of Mindful Breathing for Stress Reduction

    Science.gov (United States)

    Hedman, Anders; Feng, Shuo; Li, Haibo; Osika, Walter

    2017-01-01

    Background During the past decade, there has been a rapid increase of interactive apps designed for health and well-being. Yet, little research has been published on developing frameworks for design and evaluation of digital mindfulness facilitating technologies. Moreover, many existing digital mindfulness applications are purely software based. There is room for further exploration and assessment of designs that make more use of physical qualities of artifacts. Objective The study aimed to develop and test a new physical digital mindfulness prototype designed for stress reduction. Methods In this case study, we designed, developed, and evaluated HU, a physical digital mindfulness prototype designed for stress reduction. In the first phase, we used vapor and light to support mindful breathing and invited 25 participants through snowball sampling to test HU. In the second phase, we added sonification. We deployed a package of probes such as photos, diaries, and cards to collect data from users who explored HU in their homes. Thereafter, we evaluated our installation using both self-assessed stress levels and heart rate (HR) and heart rate variability (HRV) measures in a pilot study, in order to measure stress resilience effects. After the experiment, we performed a semistructured interview to reflect on HU and investigate the design of digital mindfulness apps for stress reduction. Results The results of the first phase showed that 22 of 25 participants (88%) claimed vapor and light could be effective ways of promoting mindful breathing. Vapor could potentially support mindful breathing better than light (especially for mindfulness beginners). In addition, a majority of the participants mentioned sound as an alternative medium. In the second phase, we found that participants thought that HU could work well for stress reduction. We compared the effect of silent HU (using light and vapor without sound) and sonified HU on 5 participants. Subjective stress levels were

  16. Reduction property of rare earth oxide doped molybdenum oxide

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Rare earth oxide doped molybdenum powders were prepared by the reduction of rare earth nitrites doped MoO3. The effect of rare earth oxide on the reduction behavior of molybdenum oxide had been studied by means of Temperature Programmed Reduction (TPR), thermal analysis, X-ray diffraction. Doping rare earth oxide in the powder could lower the reduction temperature of molybdenum oxide and decrease the particle size of molybdenum. The mechanism for the effects had been discussed in this paper.

  17. Synthesis, characterization and electrochemical studies of nanostructured CaWO{sub 4} as platinum support for oxygen reduction reaction

    Energy Technology Data Exchange (ETDEWEB)

    Farsi, Hossein [Department of Chemistry, University of Birjand, 97175-615 Birjand (Iran, Islamic Republic of); Solar Energy Research Department, University of Birjand, Birjand (Iran, Islamic Republic of); Barzgari, Zahra, E-mail: zbarzgari@birjand.ac.ir [Department of Chemistry, University of Birjand, 97175-615 Birjand (Iran, Islamic Republic of)

    2014-11-15

    Highlights: • Nanostructured CaWO{sub 4} was fabricated by co-precipitation method. • Platinum was electrodeposited onto the surface prepared nanostructured CaWO{sub 4}. • Pt/CaWO{sub 4}-graphite demonstrate good oxygen reduction reaction activity. - Abstract: In the present work, we employed nanostructured calcium tungstate as a supporting material for platinum, a well-known electrocatalyst for oxygen reduction. The co-precipitation method has been utilized to synthesize nanostructured calcium tungstate from aqueous solution. The structure and morphology of the obtained CaWO{sub 4} were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Preparation of the Pt/CaWO{sub 4}-graphite catalyst was carried out by electrodeposition of Pt onto the surface of CaWO{sub 4}/graphite electrode. The physical properties of the catalyst were determined by scanning electron microscopy analysis and energy dispersive X-ray (SEM/EDX). The electrochemical activity of the Pt/CaWO{sub 4}-graphite for the oxygen reduction reaction (ORR) was investigated in acid solution by cyclic voltammetry measurements, linear sweep voltammetry, and electrochemical impedance spectroscopy. The results revealed that the Pt/CaWO{sub 4}-graphite has higher electrocatalytic activity for oxygen reduction in comparison with Pt/graphite catalyst.

  18. Preparation of shrimp waste as aqua feedstuff: a study of physicochemical properties and in vitro digestibility

    Directory of Open Access Journals (Sweden)

    Karun Thongprajukeaw

    2014-12-01

    Full Text Available The effects of different preparation methods (boiling, microwave irradiation, oven-drying, soaking, and sun-drying for improving the protein quality of shrimp waste (SW when used as aqua feedstuff were observed. The findings from this study indicate that microwave irradiation maintained both the chemical composition and total carotenoid concentration of the SW. This method controlled the appropriate physicochemical characteristics thus promoting proteolytic digestion, as indicated by measurement of changes in pH, water solubility, microstructures, and thermal transition. The protein digestibility based on the use of digestive enzymes from Nile tilapia (Oreochromis niloticus also increased after preparation with microwave irradiation. Based on this study, improvement in the protein quality in SW may be achieved by microwave irradiation and this method may be used as an alternative method for preparing aqua feedstuff.

  19. Course of disability reduction during a pain rehabilitation program: a prospective clinical study.

    Science.gov (United States)

    Waterschoot, Franka P C; Dijkstra, Pieter U; Geertzen, Jan H B; Reneman, Michiel F

    2015-03-01

    The aim of this study was to analyze the course of reduction of disability during a pain rehabilitation program (PRP) and factors influencing this course. A prospective cohort study was carried out. All patients with chronic musculoskeletal pain treated in a PRP between March 2010 and December 2010 were eligible for this study. All patients were treated at a University-based rehabilitation center and received an outpatient multidisciplinary PRP. Main outcome measures, Pain Disability Index (PDI), and average pain measured with a numeric rating scale were measured every 2 weeks during the PRP. To analyze the course of disability, a linear mixed-effect model was applied. One hundred and twenty-eight patients participated in the study, of whom 20% dropped out during the PRP. Initial PDI (β=0.8), treatment week (β=-0.2), treatment week squared (β=0.03), average pain (β=2.3), and interaction between initial PDI and treatment week (β=-0.02) influenced the course of disability during PRP. Disability reduces during the PRP. Initial PDI, treatment week, average pain, and interaction between initial PDI and treatment week influence the course of disability reduction during the PRP. These results could aid in predicting the required duration of a PRP at the start.

  20. Effectiveness of Crown Preparation Assessment Software As an Educational Tool in Simulation Clinic: A Pilot Study.

    Science.gov (United States)

    Tiu, Janine; Cheng, Enxin; Hung, Tzu-Chiao; Yu, Chuan-Chia; Lin, Tony; Schwass, Don; Al-Amleh, Basil

    2016-08-01

    The aim of this pilot study was to evaluate the feasibility of a new tooth preparation assessment software, Preppr, as an educational tool for dental students in achieving optimal parameters for a crown preparation. In February 2015, 30 dental students in their fourth year in a five-year undergraduate dental curriculum in New Zealand were randomly selected from a pool of volunteers (N=40) out of the total class of 85. The participants were placed into one of three groups of ten students each: Group A, the control group, received only written and pictorial instructions; Group B received tutor evaluation and feedback; and Group C performed self-directed learning with the aid of Preppr. Each student was asked to prepare an all-ceramic crown on the lower first molar typodont within three hours and to repeat the exercise three times over the next four weeks. The exercise stipulated a 1 mm finish line dimension and total convergence angles (TOC) between 10 and 20 degrees. Fulfillment of these parameters was taken as an acceptable preparation. The results showed that Group C had the highest percentage of students who achieved minimum finish line dimensions and acceptable TOC angles. Those students also achieved the stipulated requirements earlier than the other groups. This study's findings provide promising data on the feasibility of using Preppr as a self-directed educational tool for students training to prepare dental crowns.