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Sample records for processed bifeo3 compounds

  1. Ferroelectric and magnetic properties in high-pressure synthesized BiFeO3 compound

    International Nuclear Information System (INIS)

    Zhai, L.; Shi, Y.G.; Gao, J.L.; Tang, S.L.; Du, Y.W.

    2011-01-01

    Highlights: → A high-density polycrystalline BiFeO 3 compound was synthesized by high-pressure annealing method. → The sample showed weak ferromagnetic at room temperature, which could be attributed to the lattice distortion induced by the high-pressure annealing. → Irregular domains were observed on the surface of the sample by piezoresponse force microscopy, and a typical hysteresis loop was obtained. - Abstract: High-density polycrystalline BiFeO 3 compound was synthesized by high-pressure annealing. Measurements of crystal structure, magnetic, and ferroelectric properties were made on the sample. It was found that the sample was almost single phase with a distorted R3c structure. The results of the X-ray photoelectron spectra demonstrate that the oxidation state of Fe in the sample is Fe 3+ . The room-temperature field dependence of magnetization for BiFeO 3 exhibits a hysteretic behavior. The observed weak ferromagnetism could be ascribed to the lattice distortion induced by the high-pressure annealing. In addition, the local ferroelectric performance of the sample was studied by piezoresponse force microscopy.

  2. Combinatorial processing libraries for bulk BiFeO3-PbTiO3 piezoelectric ceramics

    International Nuclear Information System (INIS)

    Hu, W.; Tan, X.; Rajan, K.

    2010-01-01

    A high throughput approach for generating combinatorial libraries with varying processing conditions for bulk ceramics has been developed. This approach utilized the linear temperature gradient in a tube furnace to screen a whole temperature range for optimized preparation. With this approach, the processing of 0.98[0.6BiFeO 3 -0.4PbTiO 3 ]-0.02Pb(Mg 1/3 Nb 2/3 )O 3 ceramic powders and pellets for high-temperature piezoelectric applications was demonstrated to identify the best synthesis conditions for phase purity. The dielectric property measurement on the as-processed solid solution ceramics confirmed the high Curie temperature and the improved loss tangent with the Pb(Mg 1/3 Nb 2/3 )O 3 doping. (orig.)

  3. Enhanced photocatalytic property of BiFeO_3/N-doped graphene composites and mechanism insight

    International Nuclear Information System (INIS)

    Li, Pai; Li, Lei; Xu, Maji; Chen, Qiang; He, Yunbin

    2017-01-01

    Highlights: • A hydrothermal process was used to prepare BiFeO_3/N-doped graphene composites. • BiFeO_3/N-doped graphene exhibits superior photocatalytic activity and stability. • The energy band of BiFeO_3 bends downward by ∼1.0 eV at the composite interface. • Downward band bending leads to rapid electron transfer at the composite interface. • Holes and ·OH are predominant active species in the photo-degradation process. - Abstract: A series of BiFeO_3/(N-doped) graphene composites are prepared by a facile hydrothermal method. BiFeO_3/N-doped graphene shows photocatalytic performance superior to that of BiFeO_3/graphene and pristine BiFeO_3. The enhanced photo-degradation performance of BiFeO_3/N-doped graphene are mainly attributable to the improved light absorbance of the composite, abundant active adsorption sites and high electrical charge mobility of N-doped graphene, and the downward band bending of BiFeO_3 at the composite interface. In particular, X-ray photoelectron spectroscopy analyses reveal that the electron energy band of BiFeO_3 is downward bent by 1.0 eV at the interface of BiFeO_3/N-doped graphene, because of different work functions of both materials. This downward band bending facilitates the transfer of photogenerated electrons from BiFeO_3 to N-doped graphene and prompts the separation of photo-generated electron-hole pairs, leading eventually to the enhanced photocatalytic performance.

  4. Unidirectional THz radiation propagation in BiFeO3

    Science.gov (United States)

    Room, Toomas

    The mutual coupling between magnetism and electricity present in many multiferroic materials permit the magnetic control of the electric polarization and the electric control of the magnetization. These static magnetoelectric (ME) effects are of enormous interest: The ability to write a magnetic state current-free by an electric voltage would provide a huge technological advantage. However, ME coupling changes the low energy electrodynamics of these materials in unprecedented way - optical ME effects give rise to unidirectional light propagation as recently observed in low-temperature multiferroics. The transparent direction can be switched with dc magnetic or electric field, thus opening up new possibilities to manipulate the propagation of electromagnetic waves in multiferroic materials. We studied the unidirectional transmission of THz radiation in BiFeO3 crystals, the unique multiferroic compound offering a real potential for room temperature applications. The electrodynamics of BiFeO3 at 1THz and below is dominated by the spin wave modes of cycloidal spin order. We found that the optical magnetoelectric effect generated by spin waves in BiFeO3 is robust enough to cause considerable nonreciprocal directional dichroism in the GHz-THz range even at room temperature. The supporting theory attributes the observed unidirectional transmission to the spin-current-driven dynamic ME effect. Our work demonstrates that the nonreciprocal directional dichroism spectra of low energy excitations and their theoretical analysis provide microscopic model of ME couplings in multiferroic materials. Recent THz spectroscopy studies of multiferroic materials are an important step toward the realization of optical diodes, devices which transmit light in one but not in the opposite direction.

  5. Containerless solidification of BiFeO3 oxide under microgravity

    Science.gov (United States)

    Yu, Jianding; Arai, Yasutomo; Koshikawa, Naokiyo; Ishikawa, Takehito; Yoda, Shinichi

    1999-07-01

    Containerless solidification of BiFeO3 oxide has been carried out under microgravity with Electrostatic Levitation Furnace (ELF) aboard on the sounding rocket (TR-IA). It is a first containerless experiment using ELF under microgravity for studying the solidification of oxide insulator material. Spherical BiFeO3 sample with diameter of 5mm was heated by two lasers in oxygen and nitrogen mixing atmosphere, and the sample position by electrostatic force under pinpoint model and free drift model. In order to compare the solidification behavior in microgravity with on ground, solidification experiments of BiFeO3 in crucible and drop tube were carried out. In crucible experiment, it was very difficult to get single BiFeO3 phase, because segregation of Fe2O3 occured very fast and easily. In drop tube experiment, fine homogeneous BiFeO3 microstructure was obtained in a droplet about 300 μm. It implies that containerless processing can promote the phase selection in solidification. In microgravity experiment, because the heating temperature was lower than that of estimated, the sample was heated into Fe2O3+liquid phase region. Fe2O3 single crystal grew on the surface of the spherical sample, whose sample was clearly different from that observed in ground experiments.

  6. Application of BiFeO3-based on nickel foam composites with a highly efficient catalytic activity and easily recyclable in Fenton-like process under microwave irradiation

    Science.gov (United States)

    Li, Shuo; Zhang, Guangshan; Zheng, Heshan; Zheng, Yongjie; Wang, Peng

    2018-05-01

    In this study, BiFeO3 (BFO) powders decorated on nickel foam (NF) with a high catalytic activity are prepared via a one-step microwave-assisted hydrothermal method. The factors that influence the degradation of bisphenol A (BPA) with BFO/NFs as catalysts are optimized to improve the catalytic activity in a microwave-enhanced Fenton-like process. BFO/NF exhibit a superior catalytic activity with a high BPA removal ratio (98.4%) and TOC removal ratio (69.5%) within 5 min. Results indicate that NF significantly affect the improvement of the catalytic activity of BFO because it served as a source of hydroxyl radicals (•OH) during degradation. The amount of •OH generated by BFO/NF is approximately 1.65-fold higher than that by pure BFO. After six reaction cycles, the stability and reusability of •OH remain high. These findings provide new insights into the synthesis of composites on heterogeneous catalysts with high efficiency and easy recyclability for water treatment applications.

  7. BiFeO3 Crystal Structure at Low Temperatures

    International Nuclear Information System (INIS)

    Palewicz, A.; Sosnowska, I.; Przenioslo, R.; Hewat, A.W.

    2010-01-01

    The crystal and magnetic structure of BiFeO 3 have been studied with the use of high resolution neutron diffraction between 5 K and 300 K. The atomic coordinates in BiFeO 3 are almost unchanged between 5 K and 300 K. (authors)

  8. Electric and Magnetic Properties of Sputter Deposited BiFeO3 Films

    Directory of Open Access Journals (Sweden)

    N. Siadou

    2013-01-01

    Full Text Available Polycrystalline BiFeO3 films have been magnetron sputter deposited at room temperature and subsequently heat-treated ex situ at temperatures between 400 and 700°C. The deposition was done in pure Ar atmosphere, as the use of oxygen-argon mixture was found to lead to nonstoichiometric films due to resputtering effects. At a target-to-substrate distance d=2′′ the BiFeO3 structure can be obtained in larger range process gas pressures (2–7 mTorr but the films do not show a specific texture. At d=6′′ codeposition from BiFeO3 and Bi2O3 has been used. Films sputtered at low rate tend to grow with the (001 texture of the pseudo-cubic BiFeO3 structure. As the film structure does not depend on epitaxy similar results are obtained on different substrates. A result of the volatility of Bi, Bi rich oxide phases occur after heat treatment at high temperatures. A Bi2SiO5 impurity phase forms on the substrate side, and does not affect the properties of the main phase. Despite the deposition on amorphous silicon oxide substrate weak ferromagnetism phenomena and displaced loops have been observed at low temperatures showing that their origin is not strain. Ba, La, Ca, and Sr doping suppress the formation of impurity phases and leakage currents.

  9. Anharmonic phonons and magnons in BiFeO3

    Energy Technology Data Exchange (ETDEWEB)

    Delaire, Olivier A [ORNL; Ma, Jie [ORNL; Stone, Matthew B [ORNL; Huq, Ashfia [ORNL; Gout, Delphine J [ORNL; Brown, Craig [National Institute of Standards and Technology (NIST); Wang, Kefeng [Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing; Ren, Zhifeng [Boston College, Chestnut Hill

    2012-01-01

    The phonon density of states (DOS) and magnetic excitation spectrum of polycrystalline BiFeO3 were measured for temperatures 200 < T < 750K , using inelastic neutron scattering (INS). Our results indicate that the magnetic spectrum of BiFeO3 closely resembles that of similar Fe perovskites, such as LaFeO3, despite the cycloid modulation in BiFeO3. We do not find any evidence for a spin gap. A strong T-dependence of the phonon DOS was found, with a marked broadening of the whole spectrum, providing evidence of strong anharmonicity. This anharmonicity is corroborated by large amplitude motions of Bi and O ions observed with neutron diffraction. These results highlight the importance of spin-phonon coupling in this material.

  10. Rewritable ferroelectric vortex pairs in BiFeO3

    Science.gov (United States)

    Li, Yang; Jin, Yaming; Lu, Xiaomei; Yang, Jan-Chi; Chu, Ying-Hao; Huang, Fengzhen; Zhu, Jinsong; Cheong, Sang-Wook

    2017-08-01

    Ferroelectric vortex in multiferroic materials has been considered as a promising alternative to current memory cells for the merit of high storage density. However, the formation of regular natural ferroelectric vortex is difficult, restricting the achievement of vortex memory device. Here, we demonstrated the creation of ferroelectric vortex-antivortex pairs in BiFeO3 thin films by using local electric field. The evolution of the polar vortex structure is studied by piezoresponse force microscopy at nanoscale. The results reveal that the patterns and stability of vortex structures are sensitive to the poling position. Consecutive writing and erasing processes cause no influence on the original domain configuration. The Z4 proper coloring vortex-antivortex network is then analyzed by graph theory, which verifies the rationality of artificial vortex-antivortex pairs. This study paves a foundation for artificial regulation of vortex, which provides a possible pathway for the design and realization of non-volatile vortex memory devices and logical devices.

  11. BiFeO3 thin films: Novel effects

    Indian Academy of Sciences (India)

    photolithography followed by etching of the silver film. Saturation ... Fe in +3 state. Films thus obtained are therefore highly resistive (ρ ∼ 108–109 cm) and hence exhibit saturated ferroelectric hysteresis loop (figure 3). Anomaly in ... BiFeO3 bulk sample by Rogniskaya et al [4] had indicated abrupt change in lattice parame-.

  12. Synthesis of BiFeO 3 by carbonate precipitation

    Indian Academy of Sciences (India)

    Magnetoelectric multiferroic BiFeO3 (BFO) was synthesized by a simple carbonate precipitation technique of metal nitrate solutions. X-ray powder diffraction and thermo-gravimetric analysis (TGA) revealed that the precipitate consists of an intimate mixture of crystalline bismuth carbonate and an amorphous hydroxide of ...

  13. Photoconductivity in BiFeO3 thin films

    Science.gov (United States)

    Basu, S. R.; Martin, L. W.; Chu, Y. H.; Gajek, M.; Ramesh, R.; Rai, R. C.; Xu, X.; Musfeldt, J. L.

    2008-03-01

    The optical properties of epitaxial BiFeO3 thin films have been characterized in the visible range. Variable temperature spectra show an absorption onset near 2.17eV, a direct gap (2.667±0.005eV at 300K), and charge transfer excitations at higher energy. Additionally, we report photoconductivity in BiFeO3 films under illumination from a 100mW /cm2 white light source. A direct correlation is observed between the magnitude of the photoconductivity and postgrowth cooling pressure. Dark conductivities increased by an order of magnitude when comparing films cooled in 760 and 0.1Torr. Large increases in photoconductivity are observed in light.

  14. Controllable Photovoltaic Effect of Microarray Derived from Epitaxial Tetragonal BiFeO3 Films.

    Science.gov (United States)

    Lu, Zengxing; Li, Peilian; Wan, Jian-Guo; Huang, Zhifeng; Tian, Guo; Pan, Danfeng; Fan, Zhen; Gao, Xingsen; Liu, Jun-Ming

    2017-08-16

    Recently, the ferroelectric photovoltaic (FePV) effect has attracted great interest due to its potential in developing optoelectronic devices such as solar cell and electric-optical sensors. It is important for actual applications to realize a controllable photovoltaic process in ferroelectric-based materials. In this work, we prepared well-ordered microarrays based on epitaxially tetragonal BiFeO 3 (T-BFO) films by the pulsed laser deposition technique. The polarization-dependent photocurrent image was directly observed by a conductive atomic force microscope under ultraviolet illumination. By choosing a suitable buffer electrode layer and controlling the ferroelectric polarization in the T-BFO layer, we realized the manipulation of the photovoltaic process. Moreover, based on the analysis of the band structure, we revealed the mechanism of manipulating the photovoltaic process and attributed it to the competition between two key factors, i.e., the internal electric field caused by energy band alignments at interfaces and the depolarization field induced by the ferroelectric polarization in T-BFO. This work is very meaningful for deeply understanding the photovoltaic process of BiFeO 3 -based devices at the microscale and provides us a feasible avenue for developing data storage or logic switching microdevices based on the FePV effect.

  15. Multiferroic BiFeO3-BiMnO3 Nanocheckerboard From First Principles

    OpenAIRE

    Palova, L.; Chandra, P.; Rabe, K. M.

    2010-01-01

    We present a first principles study of an unusual heterostructure, an atomic-scale checkerboard of BiFeO3-BiMnO3, and compare its properties to the two bulk constituent materials, BiFeO3 and BiMnO3. The "nanocheckerboard" is found to have a multiferroic ground state with the desired properties of each constituent: polar and ferrimagnetic due to BiFeO3 and BiMnO3, respectively. The effect of B-site cation ordering on magnetic ordering in the BiFeO3-BiMnO3 system is studied. The checkerboard ge...

  16. Electronic conduction in doped multiferroic BiFeO3

    Science.gov (United States)

    Yang, Chan-Ho; Seidel, Jan; Kim, Sang-Yong; Gajek, M.; Yu, P.; Holcomb, M. B.; Martin, L. W.; Ramesh, R.; Chu, Y. H.

    2009-03-01

    Competition between multiple ground states, that are energetically similar, plays a key role in many interesting material properties and physical phenomena as for example in high-Tc superconductors (electron kinetic energy vs. electron-electron repulsion), colossal magnetoresistance (metallic state vs. charge ordered insulating state), and magnetically frustrated systems (spin-spin interactions). We are exploring the idea of similar competing phenomena in doped multiferroics by control of band-filling. In this paper we present systematic investigations of divalent Ca doping of ferroelectric BiFeO3 in terms of structural and electronic conduction properties as well as diffusion properties of oxygen vacancies.

  17. modified BiFeO3–BaTiO3

    Indian Academy of Sciences (India)

    based perovskite structures lead- free BiFeO3–BaTiO3 solid solutions are popularly studied due to the high Curie temperature (TC). It was reported that the BiFeO3–BaTiO3 system possessed high piezoelectric. ∗. Author for correspondence ...

  18. Nanoscale Control of Exchange Bias with BiFeO3 Thin Films

    NARCIS (Netherlands)

    Martin, Lane W.; Chu, Ying-Hao; Holcomb, Mikel B.; Huijben, Mark; Yu, Pu; Han, Shu-Jen; Lee, Donkoun; Wang, Shan X.; Ramesh, R.

    2008-01-01

    We demonstrate a direct correlation between the domain structure of multiferroic BiFeO3 thin films and exchange bias of Co0.9Fe0.1/BiFeO3 heterostructures. Two distinct types of interactions − an enhancement of the coercive field (exchange enhancement) and an enhancement of the coercive field

  19. Polarized Raman study on the lattice structure of BiFeO3 films prepared by pulsed laser deposition

    KAUST Repository

    Yang, Yang; Yao, Yingbang; Zhang, Q.; Zhang, Xixiang

    2014-01-01

    Polarized Raman spectroscopy was used to study the lattice structure of BiFeO3 films on different substrates prepared by pulsed laser deposition. Interestingly, the Raman spectra of BiFeO3 films exhibit distinct polarization dependences

  20. Effect of strain on voltage-controlled magnetism in BiFeO3-based heterostructures

    Science.gov (United States)

    Wang, J. J.; Hu, J. M.; Yang, T. N.; Feng, M.; Zhang, J. X.; Chen, L. Q.; Nan, C. W.

    2014-01-01

    Voltage-modulated magnetism in magnetic/BiFeO3 heterostructures can be driven by a combination of the intrinsic ferroelectric-antiferromagnetic coupling in BiFeO3 and the antiferromagnetic-ferromagnetic exchange interaction across the heterointerface. However, ferroelectric BiFeO3 film is also ferroelastic, thus it is possible to generate voltage-induced strain in BiFeO3 that could be applied onto the magnetic layer across the heterointerface and modulate magnetism through magnetoelastic coupling. Here, we investigated, using phase-field simulations, the role of strain in voltage-controlled magnetism for these BiFeO3-based heterostructures. It is predicted, under certain condition, coexistence of strain and exchange interaction will result in a pure voltage-driven 180° magnetization reversal in BiFeO3-based heterostructures. PMID:24686503

  1. The microscopic model of BiFeO3

    Science.gov (United States)

    Fishman, R. S.

    2018-05-01

    Many years and great effort have been spent constructing the microscopic model for the room temperature multiferroic BiFeO3. However, earlier models implicitly assumed that the cycloidal wavevector q was confined to one of the three-fold symmetric axes in the hexagonal plane normal to the electric polarization. Because recent measurements indicate that q can be rotated by a magnetic field, it is essential to properly treat the anisotropy that confines q at low fields. We propose that the anisotropy energy -K3S6sin6 θ cos 6 ϕ confines the wavevectors q to the three-fold axis ϕ = 0 and ± 2 π / 3 within the hexagonal plane with θ = π / 2 .

  2. Study of magnetization and magnetoelectricity in CoFe2O4/BiFeO3 core-shell composites

    Science.gov (United States)

    Kuila, S.; Tiwary, Sweta; Sahoo, M. R.; Barik, A.; Babu, P. D.; Siruguri, V.; Birajdar, B.; Vishwakarma, P. N.

    2018-02-01

    CoFe2O4 (core)/BiFeO3 (shell) nanoparticles are prepared by varying the relative molar concentration of core and shell materials (40%CoFe2O4-60%BiFeO3, 50%CoFe2O4-50%BiFeO3, and 60%CoFe2O4-40%BiFeO3). The core-shell nature is confirmed from transmission electron microscopy on these samples. A plot of ΔM (=MFC-MZFC) vs temperature suggests the presence of two types of spin dynamics: (a) particle size dependent spin blocking and (b) spin-disorder. These two spin dynamic processes are found to contribute independently to the generation of magnetoelectric voltage. Very clear first order and second order magnetoelectric voltages are recorded. The resemblance of the first order magnetoelectric coefficient vs temperature plot to that of building up of order parameters in the mean field theory suggests that spin disorder can act like one of the essential ingredients in building the magnetoelectric coupling. The best result is obtained for the 50-50 composition sample, which may be due to better coupling of magnetostrictive CoFe2O4, and piezoelectric BiFeO3, because of the optimum thickness of shell and core.

  3. The synthesis, structure and reactivity of iron-bismuth complexes : Potential Molecular Precursors for Multiferroic BiFeO3

    OpenAIRE

    Wójcik, Katarzyna

    2009-01-01

    The thesis presented here is focused on the synthesis of iron-bismuth alkoxides and siloxides as precursors for multiferroic BiFeO3 systems. Spectrum of novel cyclopentadienyl substituted iron-bismuth complexes of the general type [{Cpy(CO)2Fe}BiX2], as potential precursors for cyclopentadienyl iron-bismuth alkoxides or siloxides [{Cpy(CO)2Fe}Bi(OR)2] (R-OtBu, OSiMe2tBu), were obtained and characterised. The use of wide range of cyclopentadienyl rings in the iron carbonyl compounds allowed fo...

  4. Structural and optical properties of cobalt doped multiferroics BiFeO3 nanostructure thin films

    Science.gov (United States)

    Prasannakumara, R.; Naik, K. Gopalakrishna

    2018-05-01

    Bismuth ferrite (BiFeO3) and Cobalt doped BiFeO3 (BiFe1-XCoXO3) nanostructure thin films were deposited on glass substrates by the sol-gel spin coating method. The X-ray diffraction patterns (XRD) of the grown BiFeO3 and BiFe1-XCoXO3 nanostructure thin films showed distorted rhombohedral structure. The shifting of peaks to higher angles was observed in cobalt doped BiFeO3. The surface morphology of the BiFeO3 and BiFe1-XCoXO3 nanostructure thin films were studied using FESEM, an increase in grain size was observed as Co concentration increases. The thickness of the nanostructure thin films was examined using FESEM cross-section. The EDX studies confirmed the elemental composition of the grown BiFeO3 and BiFe1-XCoXO3 nanostructure thin films. The optical characterizations of the grown nanostructure thin films were carried out using FTIR, it confirms the existence of Fe-O and Bi-O bands and UV-Visible spectroscopy shows the increase in optical band gap of the BiFeO3 nanostructure thin films with Co doping by ploting Tauc plot.

  5. Photoelectrochemical Performance Observed in Mn-Doped BiFeO3 Heterostructured Thin Films

    Directory of Open Access Journals (Sweden)

    Hao-Min Xu

    2016-11-01

    Full Text Available Pure BiFeO3 and heterostructured BiFeO3/BiFe0.95Mn0.05O3 (5% Mn-doped BiFeO3 thin films have been prepared by a chemical deposition method. The band structures and photosensitive properties of these films have been investigated elaborately. Pure BiFeO3 films showed stable and strong response to photo illumination (open circuit potential kept −0.18 V, short circuit photocurrent density was −0.023 mA·cm−2. By Mn doping, the energy band positions shifted, resulting in a smaller band gap of BiFe0.95Mn0.05O3 layer and an internal field being built in the BiFeO3/BiFe0.95Mn0.05O3 interface. BiFeO3/BiFe0.95Mn0.05O3 and BiFe0.95Mn0.05O3 thin films demonstrated poor photo activity compared with pure BiFeO3 films, which can be explained by the fact that Mn doping brought in a large amount of defects in the BiFe0.95Mn0.05O3 layers, causing higher carrier combination and correspondingly suppressing the photo response, and this negative influence was more considerable than the positive effects provided by the band modulation.

  6. Electric field control of magnetism using BiFeO3-based heterostructures

    International Nuclear Information System (INIS)

    Heron, J. T.; Schlom, D. G.; Ramesh, R.

    2014-01-01

    Conventional CMOS based logic and magnetic based data storage devices require the shuttling of electrons for data processing and storage. As these devices are scaled to increasingly smaller dimensions in the pursuit of speed and storage density, significant energy dissipation in the form of heat has become a center stage issue for the microelectronics industry. By taking advantage of the strong correlations between ferroic orders in multiferroics, specifically the coupling between ferroelectric and magnetic orders (magnetoelectricity), new device functionalities with ultra-low energy consumption can be envisioned. In this article, we review the advances and highlight challenges toward this goal with a particular focus on the room temperature magnetoelectric multiferroic, BiFeO 3 , exchange coupled to a ferromagnet. We summarize our understanding of the nature of exchange coupling and the mechanisms of the voltage control of ferromagnetism observed in these heterostructures

  7. Structural, magnetic and dielectric properties of Pr-modified BiFeO3 multiferroic

    International Nuclear Information System (INIS)

    Varshney, Dinesh; Sharma, Poorva; Satapathy, S.; Gupta, P.K.

    2014-01-01

    Graphical abstract: -- Highlights: • BFO and Bi 0.95 Pr 0.05 FeO 3 prepared successfully via solid state reaction route. • XRD confirms rhombohedral structure with space group R3c. • Relaxation process is attributed to thermal motion and hopping of V O 2+ . • Magnetization is enhanced in Bi 0.95 Pr 0.05 FeO 3 sample. • Enhanced magnetization stem from suppression of the spiral spin modulation. -- Abstract: The structural, vibrational, magnetic and dielectric properties of polycrystalline BiFeO 3 and Bi 0.95 Pr 0.05 FeO 3 are investigated by combining X-ray diffraction, Raman scattering spectra, magnetometry and dielectric measurements. Structural symmetry with rhombohedral R3c phase is revealed for both parent and 5% Pr substitution at Bi site, serving no chemical pressure and causes no structural transition from R3c to any other phase is identified from X-ray diffraction patterns and Raman scattering spectra. The shifting of phonon modes towards higher frequency side is attributed to lower atomic mass of Pr ion as compared to Bi ion. The magnetic measurements at room temperature indicate that Pr substitution induces ferromagnetism and discerns large and non-zero remnant magnetization as compare to pristine BiFeO 3 . Both dielectric permittivity and loss factor of Bi 0.95 Pr 0.05 FeO 3 strongly decreases with increased frequency. Significant role of hopping of oxygen ion vacancies in Bi 0.95 Pr 0.05 FeO 3 is inferred from modulus spectra and ac conductivity analysis

  8. Polarization-tuned diode behaviour in multiferroic BiFeO3 thin films

    KAUST Repository

    Yao, Yingbang; Zhang, Bei; Chen, Long; Yang, Yang; Wang, Zhihong; Alshareef, Husam N.; Zhang, Xixiang

    2012-01-01

    Asymmetric rectifying I-V behaviour of multiferroic BiFeO3 (BFO) thin films grown on transparent ITO-coated glass was quantitatively studied as a function of ferroelectric polarization. Different polarized states were established by unipolar

  9. Phase-Pure of BiFeO3 Ceramic Based on Citric Acid - Assisted Gel by Sintering Time Variation

    Science.gov (United States)

    Suastiyanti, Dwita; Ismojo

    2017-07-01

    Bismuth ferrite powder (BiFeO3/BFO) with high purity was synthesized by sol-gel process. It was used Bi5O(OH)9(NO3)4 and Fe(NO3)3.9H2O as main compound sources. Citric acid (C6H8O7) was used as fuell. As multiferroic material, BFO promises important technological applications in several devices like data strorage, spinotronics, sensor, actuator devices etc. This research would know the optimum process condition of sol-gel process to produce BFO powder by varying of sintering time. The novelty of this research is how to produce BFO in single phase by simple method. It was used calcination condition at 160°C for 4 hours and sintering condition at 600°C with varying of sintering time of 4, 6 and 8 hours. Thermogravimetric Analysis/Differential Thermal Analysis (TGA/DTA), X Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) were used to characterize the powder. Loss of mass and heat flow were seen at TGA/DTA test at 160°C approximately (used as reference of calcination temperature). BFO powder sintered at for 8 hours has no secondary phase, meanwhile for another sintering time (4 and 6 hours) it has Bi2O3 as secondary phase. It is also show at SEM observation result that powder with sintering time of 8 hours has finer grain than of 4 and 6 hours sintering at the same temperature. The grains of BFO powder has heterogenous in size, shape and still agglomerated.

  10. Photocatalytic and Magnetic Behaviors Observed in BiFeO3 Nanofibers by Electrospinning

    Directory of Open Access Journals (Sweden)

    Xuehui Zhang

    2013-01-01

    Full Text Available Perovskite-type BiFeO3 nanofibers with wave nodes-like morphology were prepared by electrospinning. The nanofibers show a highly enhanced visible-light-active photocatalytic property. The results also showed that the diameter could affect the band gap and photocatalytic performances of nanofibers. Additionally, weak ferromagnetic behaviors can be observed at room temperature, which should be correlated to the size-confinement effect on the magnetic ordering of BiFeO3 structure.

  11. Fabrication, Characterization, Properties, and Applications of Low-Dimensional BiFeO3 Nanostructures

    Directory of Open Access Journals (Sweden)

    Heng Wu

    2014-01-01

    Full Text Available Low-dimensional BiFeO3 nanostructures (e.g., nanocrystals, nanowires, nanotubes, and nanoislands have received considerable attention due to their novel size-dependent properties and outstanding multiferroic properties at room temperature. In recent years, much progress has been made both in fabrications and (microstructural, electrical, and magnetic in characterizations of BiFeO3 low-dimensional nanostructures. An overview of the state of art in BiFeO3 low-dimensional nanostructures is presented. First, we review the fabrications of high-quality BiFeO3 low-dimensional nanostructures via a variety of techniques, and then the structural characterizations and physical properties of the BiFeO3 low-dimensional nanostructures are summarized. Their potential applications in the next-generation magnetoelectric random access memories and photovoltaic devices are also discussed. Finally, we conclude this review by providing our perspectives to the future researches of BiFeO3 low-dimensional nanostructures and some key problems are also outlined.

  12. BiFeO3 epitaxial thin films and devices: past, present and future

    Science.gov (United States)

    Sando, D.; Barthélémy, A.; Bibes, M.

    2014-11-01

    The celebrated renaissance of the multiferroics family over the past ten years has also been that of its most paradigmatic member, bismuth ferrite (BiFeO3). Known since the 1960s to be a high temperature antiferromagnet and since the 1970s to be ferroelectric, BiFeO3 only had its bulk ferroic properties clarified in the mid-2000s. It is however the fabrication of BiFeO3 thin films and their integration into epitaxial oxide heterostructures that have fully revealed its extraordinarily broad palette of functionalities. Here we review the first decade of research on BiFeO3 films, restricting ourselves to epitaxial structures. We discuss how thickness and epitaxial strain influence not only the unit cell parameters, but also the crystal structure, illustrated for instance by the discovery of the so-called T-like phase of BiFeO3. We then present its ferroelectric and piezoelectric properties and their evolution near morphotropic phase boundaries. Magnetic properties and their modification by thickness and strain effects, as well as optical parameters, are covered. Finally, we highlight various types of devices based on BiFeO3 in electronics, spintronics, and optics, and provide perspectives for the development of further multifunctional devices for information technology and energy harvesting.

  13. Enhanced magnetization in morphologically and magnetically distinct BiFeO3 and La0.7Sr0.3MnO3 composites

    Science.gov (United States)

    Pillai, Shreeja; Reshi, Hilal Ahmad; Bagwaiya, Toshi; Banerjee, Alok; Shelke, Vilas

    2017-09-01

    Nanomaterials exhibit properties different from those of their bulk counterparts. The modified magnetic characteristics of manganite nanoparticles were exploited to improve magnetization in multiferroic BiFeO3 compound. We studied the composite of two morphologically and magnetically distinct compounds BiFeO3 (BFO) and La0.7Sr0.3MnO3 (LSMO). The microcrystalline BiFeO3 sample was prepared by solid state reaction method and the nanocrystalline La0.7Sr0.3MnO3 by sol-gel method. Composites with nominal compositions (1-x)BiFeO3-(x)La0.7Sr0.3MnO3 were prepared by modified solid state reaction method. The phase purity and crystal structures were checked by using X-ray diffraction. The formation of composites with phase separated BFO and LSMO was confirmed using Raman and Fourier Transform Infrared spectroscopy studies. The composite samples showed relatively high value of magnetization with finite coercivity. This improvement in magnetic behavior is ascribed to the coexistence of multiple magnetic orderings in composite samples. We scrutinized the possibility of oxygen vacancy or Fe mixed valency formation in the samples using X-ray photoelectron spectroscopy technique.

  14. Enhanced magnetic properties of chemical solution deposited BiFeO3 thin film with ZnO buffer layer

    International Nuclear Information System (INIS)

    Rajalakshmi, R.; Kambhala, Nagaiah; Angappane, S.

    2012-01-01

    Highlights: ► Enhanced magnetization of BiFeO 3 is important for strong magnetoelectric coupling. ► BiFeO 3 film with ZnO buffer layer was successfully synthesized by chemical method. ► Magnetization of BiFeO 3 has increased by more than 10 times with ZnO buffer layer. ► A mechanism for enhancement in ferromagnetism of BiFeO 3 film is proposed. - Abstract: Magnetic properties of BiFeO 3 films deposited on Si substrates with and without ZnO buffer layer have been studied in this work. We adopted the chemical solution deposition method for the deposition of BiFeO 3 as well as ZnO films. The x-ray diffraction measurements on the deposited films confirm the formation of crystalline phase of BiFeO 3 and ZnO films, while our electron microscopy measurements help to understand the morphology of few micrometers thick films. It is found that the deposited ZnO film exhibit a hexagonal particulate surface morphology, whereas BiFeO 3 film fully covers the ZnO surface. Our magnetic measurements reveal that the magnetization of BiFeO 3 has increased by more than ten times in BiFeO 3 /ZnO/Si film compared to BiFeO 3 /Si film, indicating the major role played by ZnO buffer layer in enhancing the magnetic properties of BiFeO 3 , a technologically important multiferroic material.

  15. Synthesis, microstructure and properties of BiFeO3-based multiferroic materials: A review

    Directory of Open Access Journals (Sweden)

    Bernardo, M. S.

    2014-02-01

    Full Text Available BiFeO3-based materials are currently one of the most studied multiferroics due to their possible applications at room temperature. However, among the large number of published papers there is much controversy. For example, possibility of synthesizing a pure BiFeO3 phase is still source of discussion in literature. Not even the nature of the binary Bi2O3-Fe2O3 diagram has been clarified yet. The difficulty in controlling the formation of parasite phases reaches the consolidation step. Accordingly, the sintering conditions must be carefully determined both to get dense materials and to avoid bismuth ferrite decomposition. However, the precise conditions to attain dense bismuth ferrite materials are frequently contradictory among different works. As a consequence, the reported properties habitually result opposed and highly irreproducible hampering the preparation of BiFeO3 materials suitable for practical applications. In this context, the purpose of the present review is to summarize the main researches regarding BiFeO3 synthesis, microstructure and properties in order to provide an easier understanding of these materials.Los materiales basados en BiFeO3 son en la actualidad uno de los multiferroicos más estudiados debido a sus posibles aplicaciones a temperatura ambiente. Sin embargo, entre la multitud de trabajos publicados referentes a estos materiales existe mucha controversia. Por ejemplo, la posibilidad de sintetizar una fase BiFeO3 pura es aún objeto de discusión en la bibliografía y la naturaleza de los diagramas de fases del sistema Bi2O3-Fe2O3 aún no está clara. La dificultad para controlar las fases parásitas se extiende al proceso de consolidación por lo que las condiciones de sinterización deben ser cuidadosamente controladas para obtener materiales densos y al mismo tiempo evitar la descomposición de la ferrita. No obstante, las condiciones precisas para obtener materiales densos de BiFeO3 son frecuentemente contradictorias entre los distintos trabajos. Como consecuencia, las propiedades descritas son a menudo discordantes y poco reproducibles impidiendo la preparación de materiales de BiFeO3 adecuados para sus aplicaciones prácticas. En este contexto, el propósito de esta revisión es resumir las principales investigaciones en torno a la síntesis, microestructura y propiedades de los materiales de BiFeO3 facilitando así la comprensión de los mismos.

  16. Magnetoelectric effect in (BiFeO3x–(BaTiO31-x solid solutions

    Directory of Open Access Journals (Sweden)

    Kowal Karol

    2015-03-01

    Full Text Available The aim of the present work was to study magnetoelectric effect (ME in (BiFeO3x-(BaTiO31-x solid solutions in terms of technological conditions applied in the samples fabrication process. The rapidly growing interest in these materials is caused by their multiferroic behaviour, i.e. coexistence of both electric and magnetic ordering. It creates possibility for many innovative applications, e.g. in steering the magnetic memory by electric field and vice versa. The investigated samples of various chemical compositions (i.e. x = 0.7, 0.8 and 0.9 were prepared by the solid-state sintering method under three sets of technological conditions differing in the applied temperature and soaking time. Measurements of the magnetoelectric voltage coefficient αME were performed using a dynamic lock-in technique. The highest value of αME was observed for 0.7BiFeO3-0.3BaTiO3 solid solution sintered at the highest temperature (T = 1153 K after initial electrical poling despite that the soaking time was reduced 10 times in this case.

  17. Phase pure synthesis of BiFeO3 nanopowders using diverse precursor via co-precipitation method

    International Nuclear Information System (INIS)

    Shami, M. Yasin; Awan, M.S.; Anis-ur-Rehman, M.

    2011-01-01

    Highlights: → Synthesized phase pure BiFeO 3 using diverse precursor by co-precipitation method. → Optimized synthesis and processing parameters. → Thermal behavior, structure and microstructure were analyzed. → Resistivity vs temperature and dielectric constant vs frequency were measured. → Multiferroicity at room temperature was confirmed by M-H and P-E loops. - Abstract: Amorphous powder of BiFeO 3 (BFO) was synthesized at low-temperature (80 deg. C) by co-precipitation method. Optimal synthesis conditions for phase pure BFO were obtained. Powders were calcined in the temperature range from 400 to 600 deg. C for 1 h. Iso-statically pressed powder was sintered at 500 deg. C for 2 h. Differential scanning calorimetric thermo-gram guided for phase transition, crystallization and melting temperatures. X-ray diffraction confirmed the amorphous nature of as synthesized powder and phase formation of calcined powders. Calcination at temperature ≥400 deg. C resulted in nano crystalline powders with perovskite structure. Average crystallite size increased with the increase in calcination temperature. Scanning electron microscopic studies revealed dense granular microstructure of the sintered samples. The sintered samples exhibited high dc resistivity at room temperature which decreased with the increase in temperature. Dielectric constant, dielectric loss tangent and ac conductivity measurements were carried out in the frequency range (10 Hz to 2 MHz). The samples responded weak electric and magnetic polarization at room temperature with unsaturated and hysteresis free loops, respectively.

  18. Rubber compounding and processing

    CSIR Research Space (South Africa)

    John, MJ

    2014-06-01

    Full Text Available This chapter presents an overview on the compounding and processing techniques of natural rubber compounds. The introductory portion deals with different types of rubbers and principles of rubber compounding. The primary and secondary fillers used...

  19. Pyroelectric properties and electrical conductivity in samarium doped BiFeO 3 ceramics

    KAUST Repository

    Yao, Yingbang

    2012-06-01

    Samarium (Sm 3+) doped BiFeO 3 (BFO) ceramics were prepared by a modified solid-state-reaction method which adopted a rapid heating as well as cooling during the sintering process. The pyroelectric coefficient increased from 93 to 137 μC/m 2 K as the Sm 3+ doping level increased from 1 mol% to 8 mol%. Temperature dependence of the pyroelectric coefficient showed an abrupt decrease above 80 °C in all samples, which was associated with the increase of electrical conductivity with temperature. This electrical conduction was attributed to oxygen vacancy existing in the samples. An activation energy of ∼0.7 eV for the conduction process was found to be irrespective of the Sm 3+ doping level. On the other hand, the magnetic Néel temperature (T N) decreased with increasing Sm 3+ doping level. On the basis of our results, the effects of Sm doping level on the pyroelectric and electrical properties of the BFO were revealed. © 2011 Elsevier Ltd. All rights reserved.

  20. Synthesis of BiFeO3 thin films on single-terminated Nb : SrTiO3 (111 substrates by intermittent microwave assisted hydrothermal method

    Directory of Open Access Journals (Sweden)

    Ivan Velasco-Davalos

    2016-06-01

    Full Text Available We report on a simple and fast procedure to create arrays of atomically flat terraces on single crystal SrTiO3 (111 substrates and the deposition of ferroelectric BiFeO3 thin films on such single-terminated surfaces. A microwave-assisted hydrothermal method in deionized water and ammonia solution selectively removes either (SrO34− or Ti4+ layers to ensure the same chemical termination on all terraces. Measured step heights of 0.225 nm (d111 and uniform contrast in the phase image of the terraces confirm the single termination in pure and Nb doped SrTiO3 single crystal substrates. Multiferroic BiFeO3 thin films were then deposited by the same microwave assisted hydrothermal process on Nb : SrTiO3 (111 substrates. Bi(NO33 and Fe(NO33 along with KOH served as the precursors solution. Ferroelectric behavior of the BiFeO3 films on Nb : SrTiO3 (100 substrates was verified by piezoresponse force microscopy.

  1. Pressure-induced phase transitions of multiferroic BiFeO3

    OpenAIRE

    XiaoLi, Zhang; Ye, Wu; Qian, Zhang; JunCai, Dong; Xiang, Wu; Jing, Liu; ZiYu, Wu; DongLiang, Chen

    2013-01-01

    Pressure-induced phase transitions of multiferroic BiFeO3 have been investigated using synchrotron radiation X-ray diffraction with diamond anvil cell technique at room temperature. Present experimental data clearly show that rhombohedral (R3c) phase of BiFeO3 first transforms to monoclinic (C2/m) phase at 7 GPa, then to orthorhombic (Pnma) phase at 11 GPa, which is consistent with recent theoretical ab initio calculation. However, we observe another peak at 2{\\theta}=7{\\deg} in the pressure ...

  2. Absence of morphotropic phase boundary effects in BiFeO3-PbTiO3 thin films grown via a chemical multilayer deposition method

    Science.gov (United States)

    Gupta, Shashaank; Bhattacharjee, Shuvrajyoti; Pandey, Dhananjai; Bansal, Vipul; Bhargava, Suresh K.; Peng, Ju Lin; Garg, Ashish

    2011-07-01

    We report an unusual behavior observed in (BiFeO3)1- x -(PbTiO3) x (BF- xPT) thin films prepared using a multilayer chemical solution deposition method. Films of different compositions were grown by depositing several bilayers of BF and PT precursors of varying BF and PT layer thicknesses followed by heat treatment in air. X-ray diffraction showed that samples of all compositions show mixing of two compounds resulting in a single-phase mixture, also confirmed by transmission electron microscopy. In contrast to bulk compositions, samples show a monoclinic (MA-type) structure suggesting disappearance of the morphotropic phase boundary (MPB) at x=0.30 as observed in the bulk. This is accompanied by the lack of any enhancement of the remanent polarization at the MPB, as shown by the ferroelectric measurements. Magnetic measurements showed an increase in the magnetization of the samples with increasing BF content. Significant magnetization in the samples indicates melting of spin spirals in the BF- xPT films, arising from a random distribution of iron atoms. Absence of Fe2+ ions was corroborated by X-ray photoelectron spectroscopy measurements. The results illustrate that thin film processing methodology significantly changes the structural evolution, in contrast to predictions from the equilibrium phase diagram, besides modifying the functional characteristics of the BP- xPT system dramatically.

  3. Optimization of excess Bi doping to enhance ferroic orders of spin casted BiFeO3 thin film

    International Nuclear Information System (INIS)

    Gupta, Surbhi; Gupta, Vinay; Tomar, Monika; James, A. R.; Pal, Madhuparna; Guo, Ruyan; Bhalla, Amar

    2014-01-01

    Multiferroic Bismuth Ferrite (BiFeO 3 ) thin films with varying excess bismuth (Bi) concentration were grown by chemical solution deposition technique. Room temperature multiferroic properties (ferromagnetism, ferroelectricity, and piezoelectricity) of the deposited BiFeO 3 thin films have been studied. High resolution X-ray diffraction and Raman spectroscopy studies reveal that the dominant phases formed in the prepared samples change continuously from a mixture of BiFeO 3 and Fe 2 O 3 to pure BiFeO 3 phase and, subsequently, to a mixture of BiFeO 3 and Bi 2 O 3 with increase in the concentration of excess Bi from 0% to 15%. BiFeO 3 thin films having low content (0% and 2%) of excess Bi showed the traces of ferromagnetic phase (γ-Fe 2 O 3 ). Deterioration in ferroic properties of BiFeO 3 thin films is also observed when prepared with higher content (15%) of excess Bi. Single-phased BiFeO 3 thin film prepared with 5% excess Bi concentration exhibited the soft ferromagnetic hysteresis loops and ferroelectric characteristics with remnant polarization 4.2 μC/cm 2 and saturation magnetization 11.66 emu/g. The switching of fine spontaneous domains with applied dc bias has been observed using piezoresponse force microscopy in BiFeO 3 thin films having 5% excess Bi. The results are important to identify optimum excess Bi concentration needed for the formation of single phase BiFeO 3 thin films exhibiting the improved multiferroic properties.

  4. Self-Poling of BiFeO3 Thick Films.

    Science.gov (United States)

    Khomyakova, Evgeniya; Sadl, Matej; Ursic, Hana; Daniels, John; Malic, Barbara; Bencan, Andreja; Damjanovic, Dragan; Rojac, Tadej

    2016-08-03

    Bismuth ferrite (BiFeO3) is difficult to pole because of the combination of its high coercive field and high electrical conductivity. This problem is particularly pronounced in thick films. The poling, however, must be performed to achieve a large macroscopic piezoelectric response. This study presents evidence of a prominent and reproducible self-poling effect in few-tens-of-micrometer-thick BiFeO3 films. Direct and converse piezoelectric measurements confirmed that the as-sintered BiFeO3 thick films yield d33 values of up to ∼20 pC/N. It was observed that a significant self-poling effect only appears in cases when the films are heated and cooled through the ferroelectric-paraelectric phase transition (Curie temperature TC ∼ 820 °C). These self-poled films exhibit a microstructure with randomly oriented columnar grains. The presence of a compressive strain gradient across the film thickness cooled from above the TC was experimentally confirmed and is suggested to be responsible for the self-poling effect. Finally, the macroscopic d33 response of the self-poled BiFeO3 film was characterized as a function of the driving-field frequency and amplitude.

  5. Domain wall magnetoresistance in BiFeO3 thin films measured by scanning probe microscopy

    NARCIS (Netherlands)

    Domingo, N.; Farokhipoor, S.; Santiso, J.; Noheda, B.; Catalan, G.

    2017-01-01

    We measure the magnetotransport properties of individual 71 degrees domain walls in multiferroic BiFeO3 by means of conductive-atomic force microscopy (C-AFM) in the presence of magnetic fields up to one Tesla. The results suggest anisotropic magnetoresistance at room temperature, with the sign of

  6. Local Weak Ferromagnetism in Single-Crystalline Ferroelectric BiFeO3

    DEFF Research Database (Denmark)

    Ramazanoglu, M.; Laver, Mark; Ratcliff, W.

    2011-01-01

    Polarized small-angle neutron scattering studies of single-crystalline multiferroic BiFeO3 reveal a long-wavelength spin density wave generated by ∼1° spin canting of the spins out of the rotation plane of the antiferromagnetic cycloidal order. This signifies weak ferromagnetism within mesoscopic...

  7. Magnetoelectric coupling effect in transition metal modified polycrystalline BiFeO3 thin films

    International Nuclear Information System (INIS)

    Sreenivas Puli, Venkata; Kumar Pradhan, Dhiren; Gollapudi, Sreenivasulu; Coondoo, Indrani; Panwar, Neeraj; Adireddy, Shiva; Chrisey, Douglas B.; Katiyar, Ram S.

    2014-01-01

    Rare-earth (Sm) and transition metal (Co) modified polycrystalline BiFeO 3 (BFO) thin films have been deposited on Pt/TiO 2 /SiO 2 /Si substrate successfully through pulsed laser deposition (PLD) technique. Piezoelectric, leakage current and temperature dependent dielectric and magnetic behaviour were investigated for the films. Typical “butterfly-shaped” loop were observed in BSFCO films with an effective piezoelectric constant (d 33 ) ∼94 pm/V at 0.6 MV/cm. High dielectric constant ∼900 and low dielectric loss ∼0.25 were observed at room temperature. M–H loops have shown relatively high saturation magnetization ∼35 emu/cm 3 at a maximum field of H ∼20 kOe. Enhanced magnetoelectric coupling response is observed under applied magnetic field. The multiferroic, piezoelectric, leakage current behaviours were explored. Such studies should be helpful in designing multiferroic materials based on BSFCO films. - Highlights: • Transition metal modified polycrystalline BiFeO 3 thin films prepared using PLD. • High ME-coupling response was observed in co-substituted BiFeO 3 thin films. • High magnetization ∼35 emu/cm 3 at a maximum field of H ∼20 kOe. • Low leakage current might be due to co-substitution in BiFeO 3 thin films. • A notable piezoelectric constant d 33 ∼94 pm/V was found in BiFeO 3 thin films

  8. Polarized Raman study on the lattice structure of BiFeO3 films prepared by pulsed laser deposition

    KAUST Repository

    Yang, Yang

    2014-11-01

    Polarized Raman spectroscopy was used to study the lattice structure of BiFeO3 films on different substrates prepared by pulsed laser deposition. Interestingly, the Raman spectra of BiFeO3 films exhibit distinct polarization dependences. The symmetries of the fundamental Raman modes in 50-700 cm-1 were identified based on group theory. The symmetries of the high order Raman modes in 900-1500 cm-1 of BiFeO3 are determined for the first time, which can provide strong clarifications to the symmetry of the fundamental peaks in 400-700 cm-1 in return. Moreover, the lattice structures of BiFeO3 films are identified consequently on the basis of Raman spectroscopy. BiFeO3 films on SrRuO3 coated SrTiO3 (0 0 1) substrate, CaRuO3 coated SrTiO3 (0 0 1) substrate and tin-doped indium oxide substrate are found to be in the rhombohedral structure, while BiFeO3 film on SrRuO3 coated Nb: SrTiO3 (0 0 1) substrate is in the monoclinic structure. Our results suggest that polarized Raman spectroscopy would be a feasible tool to study the lattice structure of BiFeO3 films.

  9. Ferroelectric BiFeO3as an Oxide Dye in Highly Tunable Mesoporous All-Oxide Photovoltaic Heterojunctions

    KAUST Repository

    Wang, Lingfei; Ma, He; Chang, Lei; Ma, Chun; Yuan, Guoliang; Wang, Junling; Wu, Tao

    2016-01-01

    As potential photovoltaic materials, transition-metal oxides such as BiFeO3 (BFO) are capable of absorbing a substantial portion of solar light and incorporating ferroic orders into solar cells with enhanced performance. But the photovoltaic

  10. Pressure-induced phase transitions of multiferroic BiFeO3

    International Nuclear Information System (INIS)

    Zhang Xiaoli; Dong Juncai; Liu Jing; Chen Dongliang; Wu Ye; Zhang Qian; Wu Xiang; Wu Ziyu

    2013-01-01

    Pressure-induced phase transitions of multiferroic BiFeO 3 have been investigated using synchrotron radiation X-ray diffraction with diamond anvil cell technique at room temperature. Present experimental data clearly show that rhombohedral (R3c) phase of BiFeO 3 first transforms to monoclinic (C2/m) phase at 7 GPa, then to orthorhombic (Pnma) phase at 11 GPa, which is consistent with recent theoretical ab initio calculation. However, we observe another peak at 2θ=7° in the pressure range of 5-7 GPa that has not been reported previously. Further analysis reveals that this reflection peak is attributed to the orthorhombic (Pbam) phase, indicating the coexistence of monoclinic phase with orthorhombic phase in low pressure range. (authors)

  11. Giant electroresistance of super-tetragonal BiFeO3-based ferroelectric tunnel junctions.

    Science.gov (United States)

    Yamada, Hiroyuki; Garcia, Vincent; Fusil, Stéphane; Boyn, Sören; Marinova, Maya; Gloter, Alexandre; Xavier, Stéphane; Grollier, Julie; Jacquet, Eric; Carrétéro, Cécile; Deranlot, Cyrile; Bibes, Manuel; Barthélémy, Agnès

    2013-06-25

    Ferroelectric tunnel junctions enable a nondestructive readout of the ferroelectric state via a change of resistance induced by switching the ferroelectric polarization. We fabricated submicrometer solid-state ferroelectric tunnel junctions based on a recently discovered polymorph of BiFeO3 with giant axial ratio ("T-phase"). Applying voltage pulses to the junctions leads to the highest resistance changes (OFF/ON ratio >10,000) ever reported with ferroelectric tunnel junctions. Along with the good retention properties, this giant effect reinforces the interest in nonvolatile memories based on ferroelectric tunnel junctions. We also show that the changes in resistance scale with the nucleation and growth of ferroelectric domains in the ultrathin BiFeO3 (imaged by piezoresponse force microscopy), thereby suggesting potential as multilevel memory cells and memristors.

  12. Ferroelectricity down to at least 2 nm in multiferroic BiFeO3 epitaxial thin films

    International Nuclear Information System (INIS)

    Bea, H.; Fusil, S.; Bouzehouane, K.; Sirena, M.; Herranz, G.; Jacquet, E.; Contour, J.-P.; Barthelemy, A.; Bibes, M.

    2006-01-01

    We report here on the preservation of ferroelectricity down to 2 nm in BiFeO 3 ultrathin films. The electric polarization can be switched reversibly and is stable over several days. Our findings insight on the fundamental problem of ferroelectricity at low thickness and confirm the potential of BiFeO 3 as a lead-free ferroelectric and multiferroic material for nanoscale devices. (author)

  13. Ferroelectric control of magnetization in BiFeO3/CoFe heterostructures.

    Science.gov (United States)

    Gajek, Martin; Martin, Lane; Heron, John; Seidel, Jan; Ramesh, Ramamoorthy

    2009-03-01

    The cross coupling between ferroic order parameters in multiferroics opens an alternative for the control of magnetism in magnetoelectric devices by purely electrical means. We first report on the exchange coupling between BiFeO3, an antiferromagnetic ferroelectric , and CoFe. We then show that the domain structure of the ferromagnet can be changed by poling the ferroelectric layer. Finally, we will discuss the implementation of our findings into possible device schemes.

  14. Dipole pinning effect on photovoltaic characteristics of ferroelectric BiFeO3 films

    Science.gov (United States)

    Biswas, P. P.; Thirmal, Ch.; Pal, S.; Murugavel, P.

    2018-01-01

    Ferroelectric bismuth ferrite is an attractive candidate for switchable devices. The effect of dipole pinning due to the oxygen vacancy layer on the switching behavior of the BiFeO3 thin film fabricated by the chemical solution deposition method was studied after annealing under air, O2, and N2 environment. The air annealed film showed well defined and dense grains leading to a lower leakage current and superior electrical properties compared to the other two films. The photovoltage and transient photocurrent measured under positive and negative poling elucidated the switching nature of the films. Though the air and O2 annealed films showed a switchable photovoltaic response, the response was severely affected by oxygen vacancies in the N2 annealed film. In addition, the open circuit voltage was found to be mostly dependent on the polarization of BiFeO3 rather than the Schottky barriers at the interface. This work provides an important insight into the effect of dipole pinning caused by oxygen vacancies on the switchable photovoltaic effect of BiFeO3 thin films along with the importance of stoichiometric, defect free, and phase pure samples to facilitate meaningful practical applications.

  15. Photocatalytic performances of BiFeO3 particles with the average size in nanometer, submicrometer, and micrometer

    International Nuclear Information System (INIS)

    Hao, Chunxue; FushengWen,; Xiang, Jianyong; Hou, Hang; Lv, Weiming; Lv, Yifei; Hu, Wentao; Liu, Zhongyuan

    2014-01-01

    Highlights: • Three different synthesis routes have been taken to successfully prepare the BiFeO 3 particles with the different morphologies and average size in 50, 500 nm, and 15 μm. • For photodegradation of dyes under visible irradiation in the presence of BiFeO 3 , the photocatalytic efficiency increases quickly with the decrease in size. • The enhanced photocatalytic efficiency of BiFeO 3 nanoparticles may attribute to more surface active catalytic-sites and shorter distances carriers have to migrate to the surface reaction sites. - Abstract: Three different synthesis routes were taken to successfully prepare the BiFeO 3 particles with the different morphologies and average size in 50, 500 nm, and 15 μm, respectively. The crystal structure was recognized to be a distorted rhombohedral one with the space group R3c. With the decrease in particle size, obvious decrease in peak intensity and redshift in peak position were observed for the Raman active bands. The narrow band gap was determined from the UV–vis absorption spectra, indicating the semiconducting nature of the BiFeO 3 . For photodegradation of dyes under visible irradiation in the presence of BiFeO 3 , the photocatalytic efficiency increased quickly with the decrease in size which may attribute to more surface active catalytic-sites and shorter distances carriers had to migrate to the surface reaction sites

  16. Structural, magnetic, and electrical properties of Gd-doped BiFeO3 nanoparticles with reduced particle size

    International Nuclear Information System (INIS)

    Lotey, Gurmeet Singh; Verma, N. K.

    2012-01-01

    Pure and Gd-doped BiFeO 3 nanoparticles have been synthesized by sol–gel method. The significant effects of size and Gd-doping on structural, electrical, and magnetic properties have been investigated. X-ray diffraction study reveals that the pure BiFeO 3 nanoparticles possess rhombohedral structure, but with 10% Gd-doping complete structural transformation from rhombohedral to orthorhombic has been observed. The particle size of pure and Gd-doped BiFeO 3 nanoparticles, calculated using Transmission electron microscopy, has been found to be in the range 25–15 nm. Pure and Gd-doped BiFeO 3 nanoparticles show ferromagnetic character, and the magnetization increases with decrease in particle size and increase in doping concentration. Scanning electron microscopy study reveals that grain size decreases with increase in Gd concentration. Well-saturated polarization versus electric field loop is observed for the doped samples. Leakage current density decreases by four orders by doping Gd in BiFeO 3 . The incorporation of Gd in BiFeO 3 enhances spin as well as electric polarization at room temperature. The possible origin of enhancement in these properties has been explained on the basis of dopant and its concentration, phase purity, small particle, and grain size.

  17. Magneto-optical properties of BiFeO3 thin films using surface plasmon resonance technique

    International Nuclear Information System (INIS)

    Paliwal, Ayushi; Sharma, Anjali; Tomar, Monika; Gupta, Vinay

    2014-01-01

    Indigeneously assembled surface plasmon resonance (SPR) set up has been exploited to study the magnetic field dependent optical properties of BiFeO 3 thin films. BiFeO 3 thin films have been deposited onto gold (Au) coated glass prism by using pulsed laser deposition technique. The surface plasmon modes in prism/Au/BiFeO 3 /air structure have been excited in Kretschmann configuration at the interface of Au/BiFeO 3 thin films. The SPR reflectance curves obtained for prism/Au/BiFeO 3 /air structure were utilized to investigate the optical properties of BiFeO 3 thin films at optical frequency (λ=633 nm) as a function of applied magnetic field. SPR curves shows a continuous shift towards lower angles with increasing applied magnetic field, which indicate the promising application of ferromagnetic BiFeO 3 film as a magnetic field sensor. Complex dielectric constant of deposited BiFeO 3 film was determined by fitting the experimental SPR data with Fresnel's equations. The variation of complex dielectric constant and refractive index of BiFeO 3 film was studied with increase in magnetic field, and the sensitivity of magnetic field sensor was found to be about 0.52 RIU/T

  18. Adsorption-controlled growth of BiFeO3 by MBE and integration with wide band gap semiconductors.

    Science.gov (United States)

    Ihlefeld, Jon F; Tian, Wei; Liu, Zi-Kui; Doolittle, W Alan; Bernhagen, Margitta; Reiche, Peter; Uecker, Reinhard; Ramesh, Ramamoorthy; Schlom, Darrell G

    2009-08-01

    BiFeO3 thin films have been deposited on (001) SrTiO3, (101) DyScO3, (011) DyScO3, (0001) AlGaN/GaN, and (0001) 6H-SiC single crystal substrates by reactive molecular beam epitaxy in an adsorption-controlled growth regime. This is achieved by supplying a bismuth over-pressure and utilizing the differential vapor pressures between bismuth oxides and BiFeO3 to control stoichiometry in accordance with thermodynamic calculations. Four-circle x-ray diffraction and transmission electron microscopy reveal phase-pure, epitaxial films with rocking curve full width at half maximum values as narrow as 7.2 arc seconds (0.002 degrees). Epitaxial growth of (0001)-oriented BiFeO3 thin films on (0001) GaN, including AlGaN HEMT structures, and (0001) SiC has been realized using intervening epitaxial (111) SrTiO3 / (100) TiO2 buffer layers. The epitaxial BiFeO3 thin films have 2 in-plane orientations: [1120] BiFeO3 || [1120] GaN (SiC) plus a twin variant related by a 180 degrees in-plane rotation. This epitaxial integration of the ferroelectric with the highest known polarization, BiFeO3, with high bandgap semiconductors is an important step toward novel field-effect devices.

  19. Effect of synthesis route on the multiferroic properties of BiFeO3: A comparative study between solid state and sol–gel methods

    International Nuclear Information System (INIS)

    Suresh, Pittala; Srinath, S.

    2015-01-01

    Polycrystalline BiFeO 3 (BFO) powder was prepared through optimized solid state (SS) and sol–gel (SG) reaction methods. The effect of preparation routes on the crystal purity and multiferroic properties of the BFO was investigated. Sol–gel synthesis results almost a single-phase material at relatively lower temperatures while the solid-state method results into BFO with a small amount of Bi 2 Fe 4 O 9 secondary phase. The grain size of SG processed sample reduces to half the size of the one that is prepared by SS. Elemental analysis shows a stoichiometric Bi:Fe content for SG samples by restricting the Bi loss. In comparison with the SS samples, dielectric constant of SG samples exhibit higher values with Maxwell–Wagner type dielectric dispersion. A cusp at 50 K was seen in M–T curves for SS samples, for which no frequency dependence was observed in a.c susceptibility measurements ruling out the earlier predictions of spin glass nature in this system. M−H loops show a typical antiferromagnetic nature at 300 K while a weak ferromagnetic behavior is found at 10 K. A slight increase in H C and M r was observed for SG samples over SS. The improved properties of SG processed BFO makes it more promising for applications. - Highlights: • Optimized conditions to attain the BiFeO 3 with minimized impurities are reported. • The influence of the impurities on the dielectric, magnetic properties is reported. • Maxwell–Wagner relaxation is found for BiFeO 3 prepared by sol–gel technique. • a.c. susceptibility measurements ruled out the possibility of spin glass nature. • The anomalous behavior of H C with the temperature is reported

  20. Structure and phase transition of BiFeO3 cubic micro-particles prepared by hydrothermal method

    International Nuclear Information System (INIS)

    Zhou, Jian-Ping; Yang, Ruo-Lin; Xiao, Rui-Juan; Chen, Xiao-Ming; Deng, Chao-Yong

    2012-01-01

    Graphical abstract: Bismuth ferrite (BiFeO 3 ) cubic micro-particles with smooth surfaces were synthesized. BiFeO 3 has a hexagonal perovskite structure with a space group R3c below 370 °C and rhombohedral perovskite structure with a space group R3m below 755 °C, undergoes a phase transition in the temperature range of 755–817 °C to a cubic structure, then decompose to liquid and Fe 2 O 3 above 939 °C. Highlights: ► BiFeO 3 micro-particles with smooth surface were synthesized by hydrothermal method. ► BiFeO 3 enjoys hexagonal structure with well element ratio and chemical valence. ► BiFeO 3 transition from rhombohedral phase to cubic phase lasts 60 °C. -- Abstract: Single-phase bismuth ferrite (BiFeO 3 ) powders were synthesized with a hydrothermal method by controlling the experimental conditions carefully. The powder structure, morphology and composition were characterized by using X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscope, Raman measurement and X-ray photoelectron spectroscopy. The particles change from irregular agglomerations to regular cubes with increasing KOH concentration. The large BiFeO 3 cubic particles enjoy much smooth surfaces with well-matched element ratio (Bi:Fe:O = 1:1:3) and chemical valence (Bi 3+ , Fe 3+ and O 2− ). The high temperature XRD and differential scanning calorimetry show that BiFeO 3 powders have a hexagonal perovskite structure with a space group R3c below 370 °C and a rhombohedral structure with a space group R3m below 755 °C. BiFeO 3 undergoes a phase transition in the temperature range of 755–817 °C from rhombohedral structure to a cubic phase, then decomposes to liquid and Fe 2 O 3 above 939 °C.

  1. Process for compound transformation

    KAUST Repository

    Basset, Jean-Marie

    2016-12-29

    Embodiments of the present disclosure provide for methods of using a catalytic system to chemically transform a compound (e.g., a hydrocarbon). In an embodiment, the method does not employ grafting the catalyst prior to catalysis. In particular, embodiments of the present disclosure provide for a process of hydrocarbon (e.g., C1 to C20 hydrocarbon) metathesis (e.g., alkane, olefin, or alkyne metathesis) transformation, where the process can be conducted without employing grafting prior to catalysis.

  2. Domain wall magnetoresistance in BiFeO3 thin films measured by scanning probe microscopy.

    Science.gov (United States)

    Domingo, N; Farokhipoor, S; Santiso, J; Noheda, B; Catalan, G

    2017-08-23

    We measure the magnetotransport properties of individual 71° domain walls in multiferroic BiFeO 3 by means of conductive-atomic force microscopy (C-AFM) in the presence of magnetic fields up to one Tesla. The results suggest anisotropic magnetoresistance at room temperature, with the sign of the magnetoresistance depending on the relative orientation between the magnetic field and the domain wall plane. A consequence of this finding is that macroscopically averaged magnetoresistance measurements for domain wall bunches are likely to underestimate the magnetoresistance of each individual domain wall.

  3. Transition metal modified bulk BiFeO3 with improved magnetization and linear magneto-electric coupling

    International Nuclear Information System (INIS)

    Puli, Venkata Sreenivas; Kumar, A.; Panwar, N.; Panwar, I.C.; Katiyar, R.S.

    2011-01-01

    Highlights: → Present composition (Bi 0.9 Sm 0.10 Fe 0.95 Co 0.05 O 3 (BSFCO) have shown very high magnetization compared to parent BFO. → The magnetic hysteresis loops are well saturated with high saturation magnetization 2.89 emu/gm (unpoled and unleached) and 2.18 emu/gm (poled and unleached) respectively. → Converse ME coupling were found 0.8e-10 s m -1 (H||E) and 0.6-0.8 x 10 -10 s m -1 (H-perpendicular E) which are better than the single phase multiferroic obeying linear ME coupling. - Abstract: At present BiFeO 3 (BFO) is the most attractive and sole example, which possesses low magnetization value, high leakage current and low polarization in ceramic form. Single-phase room temperature multiferroics are rare in nature. This paper deals with the improved magnetic and observed linear magneto-electric coupling in Co and Sm co-doped BiFeO 3 ceramics synthesized by sol-gel process at low temperature ∼600 deg. C. As synthesized Bi 0.9 Sm 0.10 Fe 0.95 Co 0.05 O 3 (BSFCO) showed high impurities phases (20%) over wide range of calcination temperatures. Impurity phases reduced drastically from 20% to 5% after leaching with nitric acid. However the electrical and the magnetic properties were almost the same for both phases. Well-defined magnetic hysteresis with high magnetic moment was found at room temperature. Ferroelectric polarization studies demonstrated similar values and shape as reported in literature for the pure bulk BFO. Linear magneto-electric (ME) coupling and weak ME coefficient (α) ∼ 0.6 e-10 s m -1 were observed in the co-doped BFO. The origin of the strong ferromagnetic property in our samples may be due to the presence of rare earth and transition metal ions at the lattice sites of BFO or due to impurity phase, since we have not seen any change in magnetization with reduction of impurity phase the later effect is more unlikely.

  4. Effects of Interfaces on the Structure and Novel Physical Properties in Epitaxial Multiferroic BiFeO3 Ultrathin Films

    Directory of Open Access Journals (Sweden)

    Chuanwei Huang

    2014-07-01

    Full Text Available In functional oxide films, different electrical/mechanical boundaries near film surfaces induce rich phase diagrams and exotic phenomena. In this paper, we review some key points which underpin structure, phase transition and related properties in BiFeO3 ultrathin films. Compared with the bulk counterparts, we survey the recent results of epitaxial BiFeO3 ultrathin films to illustrate how the atomic structure and phase are markedly influenced by the interface between the film and the substrate, and to emphasize the roles of misfit strain and depolarization field on determining the domain patterns, phase transformation and associated physical properties of BiFeO3 ultrathin films, such as polarization, piezoelectricity, and magnetism. One of the obvious consequences of the misfit strain on BiFeO3 ultrathin films is the emergence of a sequence of phase transition from tetragonal to mixed tetragonal & rhombohedral, the rhombohedral, mixed rhombohedral & orthorhombic, and finally orthorhombic phases. Other striking features of this system are the stable domain patterns and the crossover of 71° and 109° domains with different electrical boundary conditions on the film surface, which can be controlled and manipulated through the depolarization field. The external field-sensitive enhancements of properties for BiFeO3 ultrathin films, including the polarization, magnetism and morphotropic phase boundary-relevant piezoelectric response, offer us deeper insights into the investigations of the emergent properties and phenomena of epitaxial ultrathin films under various mechanical/electrical constraints. Finally, we briefly summarize the recent progress and list open questions for future study on BiFeO3 ultrathin films.

  5. Understanding Strain-Induced Phase Transformations in BiFeO3 Thin Films.

    Science.gov (United States)

    Dixit, Hemant; Beekman, Christianne; Schlepütz, Christian M; Siemons, Wolter; Yang, Yongsoo; Senabulya, Nancy; Clarke, Roy; Chi, Miaofang; Christen, Hans M; Cooper, Valentino R

    2015-08-01

    Experiments demonstrate that under large epitaxial strain a coexisting striped phase emerges in BiFeO 3 thin films, which comprises a tetragonal-like ( T ') and an intermediate S ' polymorph. It exhibits a relatively large piezoelectric response when switching between the coexisting phase and a uniform T ' phase. This strain-induced phase transformation is investigated through a synergistic combination of first-principles theory and experiments. The results show that the S ' phase is energetically very close to the T ' phase, but is structurally similar to the bulk rhombohedral ( R ) phase. By fully characterizing the intermediate S ' polymorph, it is demonstrated that the flat energy landscape resulting in the absence of an energy barrier between the T ' and S ' phases fosters the above-mentioned reversible phase transformation. This ability to readily transform between the S ' and T ' polymorphs, which have very different octahedral rotation patterns and c / a ratios, is crucial to the enhanced piezoelectricity in strained BiFeO 3 films. Additionally, a blueshift in the band gap when moving from R to S ' to T ' is observed. These results emphasize the importance of strain engineering for tuning electromechanical responses or, creating unique energy harvesting photonic structures, in oxide thin film architectures.

  6. Structural and electrical characterization of BiFeO3-NaTaO3 multiferroic

    International Nuclear Information System (INIS)

    Mohanty, Suchismita; Choudhary, R.N.P.; Parida, B.N.; Padhee, R.

    2014-01-01

    Using a standard high-temperature solid-state reaction technique, polycrystalline samples of (Bi 1-x , Na x ) (Fe 1-x , Ta x ) O 3 (x = 0.0, 0.5) were prepared. The formation of the desired materials was confirmed by X-ray diffraction. The surface texture of the prepared materials recorded by scanning electron microscope exhibits a uniform grain distribution with small voids suggesting the formation of high-density pellet samples. The impedance and dielectric properties of the materials were investigated as a function of temperature and frequency. The relative dielectric constant and loss tangent of BiFeO 3 decrease on addition of NaTaO 3 (x = 0.5). The effect of addition of NaTaO 3 on grain and grain boundary contributions in the resistive and capacitive components of BiFeO 3 was studied using complex impedance spectroscopy. The value of activation energy due to both grain and grain boundary of both the samples is nearly same. The nature of variation of dc conductivity confirms the Arrhenius behavior of the materials. Study of frequency dependence of ac conductivity suggests that the materials obey Jonscher's universal power law and the presence of ionic conductivity. (orig.)

  7. Electric modulation of conduction in multiferroic Ca-doped BiFeO3 films

    Science.gov (United States)

    Yang, C.-H.; Seidel, J.; Kim, S. Y.; Rossen, P. B.; Yu, P.; Gajek, M.; Chu, Y. H.; Martin, L. W.; Holcomb, M. B.; He, Q.; Maksymovych, P.; Balke, N.; Kalinin, S. V.; Baddorf, A. P.; Basu, S. R.; Scullin, M. L.; Ramesh, R.

    2009-06-01

    Many interesting materials phenomena such as the emergence of high-Tc superconductivity in the cuprates and colossal magnetoresistance in the manganites arise out of a doping-driven competition between energetically similar ground states. Doped multiferroics present a tantalizing evolution of this generic concept of phase competition. Here, we present the observation of an electronic conductor-insulator transition by control of band-filling in the model antiferromagnetic ferroelectric BiFeO3 through Ca doping. Application of electric field enables us to control and manipulate this electronic transition to the extent that a p-n junction can be created, erased and inverted in this material. A `dome-like' feature in the doping dependence of the ferroelectric transition is observed around a Ca concentration of ~1/8, where a new pseudo-tetragonal phase appears and the electric modulation of conduction is optimized. Possible mechanisms for the observed effects are discussed on the basis of the interplay of ionic and electronic conduction. This observation opens the door to merging magnetoelectrics and magnetoelectronics at room temperature by combining electronic conduction with electric and magnetic degrees of freedom already present in the multiferroic BiFeO3.

  8. Local and average structure of Mn- and La-substituted BiFeO3

    Science.gov (United States)

    Jiang, Bo; Selbach, Sverre M.

    2017-06-01

    The local and average structure of solid solutions of the multiferroic perovskite BiFeO3 is investigated by synchrotron X-ray diffraction (XRD) and electron density functional theory (DFT) calculations. The average experimental structure is determined by Rietveld refinement and the local structure by total scattering data analyzed in real space with the pair distribution function (PDF) method. With equal concentrations of La on the Bi site or Mn on the Fe site, La causes larger structural distortions than Mn. Structural models based on DFT relaxed geometry give an improved fit to experimental PDFs compared to models constrained by the space group symmetry. Berry phase calculations predict a higher ferroelectric polarization than the experimental literature values, reflecting that structural disorder is not captured in either average structure space group models or DFT calculations with artificial long range order imposed by periodic boundary conditions. Only by including point defects in a supercell, here Bi vacancies, can DFT calculations reproduce the literature results on the structure and ferroelectric polarization of Mn-substituted BiFeO3. The combination of local and average structure sensitive experimental methods with DFT calculations is useful for illuminating the structure-property-composition relationships in complex functional oxides with local structural distortions.

  9. Pinning, rotation, and metastability of BiFeO3 cycloidal domains in a magnetic field

    Science.gov (United States)

    Fishman, Randy S.

    2018-01-01

    Earlier models for the room-temperature multiferroic BiFeO3 implicitly assumed that a very strong anisotropy restricts the domain wave vectors q to the threefold-symmetric axis normal to the static polarization P . However, recent measurements demonstrate that the domain wave vectors q rotate within the hexagonal plane normal to P away from the magnetic field orientation m . We show that the previously neglected threefold anisotropy K3 restricts the wave vectors to lie along the threefold axis in zero field. Taking m to lie along a threefold axis, the domain with q parallel to m remains metastable below Bc 1≈7 T. Due to the pinning of domains by nonmagnetic impurities, the wave vectors of the other two domains start to rotate away from m above 5.6 T, when the component of the torque τ =M ×B along P exceeds a threshold value τpin. Since τ =0 when m ⊥q , the wave vectors of those domains never become completely perpendicular to the magnetic field. Our results explain recent measurements of the critical field as a function of field orientation, small-angle neutron scattering measurements of the wave vectors, as well as spectroscopic measurements with m along a threefold axis. The model developed in this paper also explains how the three multiferroic domains of BiFeO3 for a fixed P can be manipulated by a magnetic field.

  10. Tuning magnetic properties of magnetoelectric BiFeO 3-NiFe 2O 4 nanostructures

    Science.gov (United States)

    Crane, S. P.; Bihler, C.; Brandt, M. S.; Goennenwein, S. T. B.; Gajek, M.; Ramesh, R.

    2009-02-01

    Multifunctional thin film nanostructures containing soft magnetic materials such as nickel ferrite are interesting for potential applications in microwave signal processing because of the possibility to shrink the size of device architecture and limit device power consumption. An essential prerequisite to future applications of such a system is a firm understanding of its magnetic properties. We show that nanostructures composed of ferrimagnetic NiFe 2O 4 pillars in a multiferroic BiFeO 3 matrix can be tuned magnetically by altering the aspect ratio of the pillars by depositing films of varying thickness. Magnetic anisotropy is studied using ferromagnetic resonance, which shows that the uniaxial magnetic anisotropy in the growth direction changes sign upon increasing the film thickness. The magnitude of this anisotropy contribution can be explained via a combination of shape and magnetostatic effects, using the object-oriented micromagnetic framework (OOMMF). The key factors determining the magnetic properties of the films are shown to be the aspect ratio of individual pillars and magnetostatic interactions between neighboring pillars.

  11. Tuning magnetic properties of magnetoelectric BiFeO3-NiFe2O4 nanostructures

    International Nuclear Information System (INIS)

    Crane, S.P.; Bihler, C.; Brandt, M.S.; Goennenwein, S.T.B.; Gajek, M.; Ramesh, R.

    2009-01-01

    Multifunctional thin film nanostructures containing soft magnetic materials such as nickel ferrite are interesting for potential applications in microwave signal processing because of the possibility to shrink the size of device architecture and limit device power consumption. An essential prerequisite to future applications of such a system is a firm understanding of its magnetic properties. We show that nanostructures composed of ferrimagnetic NiFe 2 O 4 pillars in a multiferroic BiFeO 3 matrix can be tuned magnetically by altering the aspect ratio of the pillars by depositing films of varying thickness. Magnetic anisotropy is studied using ferromagnetic resonance, which shows that the uniaxial magnetic anisotropy in the growth direction changes sign upon increasing the film thickness. The magnitude of this anisotropy contribution can be explained via a combination of shape and magnetostatic effects, using the object-oriented micromagnetic framework (OOMMF). The key factors determining the magnetic properties of the films are shown to be the aspect ratio of individual pillars and magnetostatic interactions between neighboring pillars

  12. Local conductivity and the role of vacancies around twin walls of (001)-BiFeO3 thin films

    NARCIS (Netherlands)

    Farokhipoor, S.; Noheda, Beatriz

    2012-01-01

    BiFeO3 thin films epitaxially grown on SrRuO3-buffered (001)-oriented SrTiO3 substrates show orthogonal bundles of twin domains, each of which contains parallel and periodic 71 degrees domain walls. A smaller amount of 109 degrees domain walls are also present at the boundaries between two adjacent

  13. Ultrathin limit and dead-layer effects in local polarization switching of BiFeO3

    NARCIS (Netherlands)

    Maksymovych, P.; Huijben, Mark; Pan, M.; Jesse, S.; Balke, N.; Chu, Y.H.; Chang, H.J.; Borisevich, A.Y.; Baddorf, A.P.; Rijnders, Augustinus J.H.M.; Blank, David H.A.; Ramesh, R.; Kalinin, S.V.

    2012-01-01

    Using piezoresponse force microscopy in an ultrahigh vacuum, polarization switching has been detected and quantified in epitaxial BiFeO3 films from 200 to about 4 unit cells thick. Local remnant piezoresponse was utilized to probe both ferroelectric properties and effects of imperfect electrical

  14. Structural phase transition and magnetic properties of Er-doped BiFeO3 nanoparticles

    International Nuclear Information System (INIS)

    Li, Y T; Zhang, H G; Dong, X G; Li, Q; Mao, W W; Dong, C L; Ren, S L; Li, X A; Wei, S Q

    2013-01-01

    The structural phase transition and local structural distortion of Er-doped BiFeO 3 nanoparticles have been discussed in order to understand the variation of magnetic properties in this system. The X-ray diffraction patterns and X-ray absorption fine structure of these samples demonstrate that there is structural phase transition and no obvious local structural distortion with the increasing of doping concentration. Unfortunately, no ferromagnetic properties have been observed even at a lower temperature. And the X-ray absorption spectra of Fe 2p core level of these samples are totally same, especially the energy positions do not shift which means the consistent valence states of Fe ions.

  15. Critical slowing down of spin fluctuations in BiFeO3

    International Nuclear Information System (INIS)

    Scott, J F; Singh, M K; Katiyar, R S

    2008-01-01

    In earlier work we reported the discovery of phase transitions in BiFeO 3 evidenced by divergences in the magnon light-scattering cross-sections at 140 and 201 K (Singh et al 2008 J. Phys.: Condens. Matter 20 252203) and fitted these intensity data to critical exponents α = 0.06 and α' = 0.10 (Scott et al 2008 J. Phys.: Condens. Matter 20 322203), under the assumption that the transitions are strongly magnetoelastic (Redfern et al 2008 at press) and couple to strain divergences through the Pippard relationship (Pippard 1956 Phil. Mag. 1 473). In the present paper we extend those criticality studies to examine the magnon linewidths, which exhibit critical slowing down (and hence linewidth narrowing) of spin fluctuations. The linewidth data near the two transitions are qualitatively different and we cannot reliably extract a critical exponent ν, although the mean field value ν = 1/2 gives a good fit near the lower transition.

  16. Ferroelectric and electrical characterization of multiferroic BiFeO3 at the single nanoparticle level

    Energy Technology Data Exchange (ETDEWEB)

    Vasudevan, Rama K [ORNL; Bogle, K A [University of New South Wales, Sydney, Australia; Kumar, Amit [ORNL; Jesse, Stephen [ORNL; Magaraggia, R [University of Glasgow; Stamps, R [University of Glasgow; Ogale, S [National Chemical Laboratory, India; Potdar, H S [National Chemical Laboratory, India

    2011-01-01

    Ferroelectric BiFeO3 (BFO) nanoparticles deposited on epitaxial substrates of SrRuO3 (SRO) and La1xSrxMnO3 (LSMO) were studied using band excitation piezoresponse spectroscopy (BEPS), piezoresponse force microscopy (PFM), and ferromagnetic resonance (FMR). BEPS confirms that the nanoparticles are ferroelectric in nature. Switching behavior of nanoparticle clusters were studied and showed evidence for inhomogeneous switching. The dimensionality of domains within nanoparticles was found to be fractal in nature, with a dimensionality constant of 1.4, on par with ferroelectric BFO thin-films under 100 nm in thickness. Ferromagnetic resonance studies indicate BFO nanoparticles only weakly affect the magnetic response of LSMO.

  17. Tetragonal BiFeO3 on yttria-stabilized zirconia

    International Nuclear Information System (INIS)

    Liu, Heng-Jui; Du, Yu-Hao; Gao, Peng; Ikuhara, Yuichi; Huang, Yen-Chin; Chen, Yi-Chun; Chen, Hsiao-Wen; Liu, Hsiang-Lin; He, Qing; Chu, Ying-Hao

    2015-01-01

    High structural susceptibility of multiferroic BiFeO 3 (BFO) makes it a potential replacement of current Pb-based piezoelectrics. In this study, a tetragonal phase is identified based on a combination of x-ray diffraction, scanning transmission electronic microscopy, x-ray absorption spectroscopy, and Raman spectroscopy when BFO is grown on yttria-stabilized zirconia (YSZ) substrates. To distinguish the discrepancy between this tetragonal phase and common cases of monoclinic BFO, piezoelectric force microscopy images and optical property are also performed. It shows a lower electrostatic energy of ferroelectric domains and a large reduction of band gap for BFO grown on YSZ substrate comparing to the well-known one grown on LaAlO 3 substrate. Our findings in this work can provide more insights to understand the structural diversity of multiferroic BFO system for further applications

  18. Multiferroic properties of BiFeO3/BaTiO3 multilayered thin films

    International Nuclear Information System (INIS)

    Sharma, Savita; Tomar, Monika; Kumar, Ashok; Puri, Nitin K.; Gupta, Vinay

    2014-01-01

    Multilayered structures of multiferroic BiFeO 3 (BFO) and ferroelectric BaTiO 3 (BTO) have been fabricated using pulsed laser deposition (PLD). Ferromagnetic and ferroelectric properties of the multilayered system (BFO/BTO) have been investigated. It could be inferred that the magnetization increases with the incorporation of BTO buffer layer, which indicates a coupling between the ferroelectric and ferromagnetic orders. Vibrating sample magnetometer (VSM) measurements performed on the prepared multiferroic samples show that the magnetization is significantly increased (M s =56.88 emu/cm 3 ) for the multilayer system with more number of layers (four) keeping the total thickness of the multilayered system constant (350 nm) meanwhile maintaining the sufficiently enhanced ferroelectric properties (P r =29.68 µC/cm 2 )

  19. Polarization-tuned diode behaviour in multiferroic BiFeO3 thin films

    KAUST Repository

    Yao, Yingbang

    2012-12-28

    Asymmetric rectifying I-V behaviour of multiferroic BiFeO3 (BFO) thin films grown on transparent ITO-coated glass was quantitatively studied as a function of ferroelectric polarization. Different polarized states were established by unipolar or bipolar poling with various applied electric fields. The effects of polarization relaxation and fatigue on the currents were also investigated. We found that the conduction currents and the associated rectifications were controlled by the amplitude and direction of the polarization. We clearly observed the linear dependence of the current on the polarization. It is suggested that the space-charge-limited conduction and the charge injection at the Schottky interface between the film and the electrodes dominate the current. The electrically controlled rectifying behaviour observed in this study may be useful in nonvolatile resistance memory devices or tunable diodes. © 2013 IOP Publishing Ltd.

  20. Photovoltaic effect in transition metal modified polycrystalline BiFeO3 thin films

    International Nuclear Information System (INIS)

    Puli, Venkata Sreenivas; Chrisey, Douglas B; Pradhan, Dhiren Kumar; Katiyar, Rajesh Kumar; Misra, Pankaj; Scott, J F; Katiyar, Ram S; Coondoo, Indrani; Panwar, Neeraj

    2014-01-01

    We report photovoltaic (PV) effect in multiferroic Bi 0.9 Sm 0.1 Fe 0.95 Co 0.05 O 3 (BSFCO) thin films. Transition metal modified polycrystalline BiFeO 3 (BFO) thin films have been deposited on Pt/TiO 2 /SiO 2 /Si substrate successfully through pulsed laser deposition (PLD). PV response is observed under illumination both in sandwich and lateral electrode configurations. The open-circuit voltage (V oc ) and the short-circuit current density (J sc ) of the films in sandwich electrode configuration under illumination are measured to be 0.9 V and −0.051 µA cm −2 . Additionally, we report piezoresponse for BSFCO films, which confirms ferroelectric piezoelectric behaviour. (paper)

  1. Electric-field control of spin waves in multiferroic BiFeO3: Theory

    Science.gov (United States)

    de Sousa, Rogério; Rovillain, P.; Gallais, Y.; Sacuto, A.; Méasson, M. A.; Colson, D.; Forget, A.; Bibes, M.; Barthélémy, A.; Cazayous, M.

    2011-03-01

    Our recent experiment demonstrated gigantic (30%) electric-field tuning of magnon frequencies in multiferroic BiFeO3. We demonstrate that the origin of this effect is related to two linear magnetoelectric interactions that couple the component of electric field perpendicular to the ferroelectric vector to a quadratic form of the Néel vector. We calculate the magnon spectra due to each of these interactions and show that only one of them is consistent with experimental data. At high electric fields, this interaction induces a phase transition to a homogeneous state, and the multi-magnon spectra will fuse into two magnon frequencies. We discuss the possible microscopic mechanisms responsible for this novel interaction and the prospect for applications in magnonics. We acknowledge support from NSERC-Discovery (Canada) and the Agence Nationale pour la Recherche (France).

  2. Observation of room temperature saturated ferroelectric polarization in Dy substituted BiFeO3 ceramics

    KAUST Repository

    Zhang, Shuxia

    2012-04-06

    High quality Bi1− x Dy x FeO3 (0 ≤ x ≤ 0.15) ceramics have been fabricated by sintering Dy-doped BiFeO3 (BFO) precursor powders at a low temperature of 780 °C. The magnetic properties of BFO were improved by the introduction of Dy on the Bi-site. More importantly, well saturated ferroelectric hysteresis loops and polarization switching currents have been observed at room temperature. A large remnant polarization (2P r) value of 62 μC/cm2 is achieved, which is the highest value reported so far for rare-earth-doped BFO ceramics. Moreover, mechanisms for improved multiferroic properties depending on chemical doping-caused structure evolutions have also been discussed.

  3. Observation of room temperature saturated ferroelectric polarization in Dy substituted BiFeO3 ceramics

    KAUST Repository

    Zhang, Shuxia; Wang, Lei; Chen, Yao; Wang, Dongliang; Yao, Yingbang; Ma, Yanwei

    2012-01-01

    High quality Bi1− x Dy x FeO3 (0 ≤ x ≤ 0.15) ceramics have been fabricated by sintering Dy-doped BiFeO3 (BFO) precursor powders at a low temperature of 780 °C. The magnetic properties of BFO were improved by the introduction of Dy on the Bi-site. More importantly, well saturated ferroelectric hysteresis loops and polarization switching currents have been observed at room temperature. A large remnant polarization (2P r) value of 62 μC/cm2 is achieved, which is the highest value reported so far for rare-earth-doped BFO ceramics. Moreover, mechanisms for improved multiferroic properties depending on chemical doping-caused structure evolutions have also been discussed.

  4. Giant Polarization Rotation in BiFeO3/SrTiO3 Thin Films.

    Science.gov (United States)

    Langner, M. C.; Chu, Y. H.; Martin, L. M.; Gajek, M.; Ramesh, R.; Orenstein, J.

    2008-03-01

    We use optical second harmonic generation to probe dynamics of the ferroelectric polarization in (111) oriented BiFeO3 thin films grown on SrTiO3 substrates. The second harmonic response indicates 3m point group symmetry and is consistent with a spontaneous polarization normal to the surface of the film. We measure large changes in amplitude and lowering of symmetry, consistent with polarization rotation, when modest electric fields are applied in the plane of the film. At room temperature the rotation is an order of magnitude larger than expected from reported values of the dielectric constant and increases further (as 1/T) as temperature is lowered. We propose a substrate interaction model to explain these results.

  5. Electrical conduction at domain walls in multiferroic BiFeO3

    Science.gov (United States)

    Seidel, Jan; Martin, Lane; He, Qing; Zhan, Qian; Chu, Ying-Hao; Rother, Axel; Hawkridge, Michael; Maksymovych, Peter; Yu, Pu; Gajek, Martin; Balke, Nina; Kalinin, Sergei; Gemming, Sybille; Wang, Feng; Catalán, Gustau; Scott, James; Spaldin, Nicola; Orenstein, Joseph; Ramesh, Ramamoorthy

    2009-03-01

    We report the observation of room temperature electronic conductivity at ferroelectric domain walls in BiFeO3. The origin and nature of the observed conductivity is probed using a combination of conductive atomic force microscopy, high resolution transmission electron microscopy and first-principles density functional computations. We show that a structurally driven change in both the electrostatic potential and local electronic structure (i.e., a decrease in band gap) at the domain wall leads to the observed electrical conductivity. We estimate the conductivity in the wall to be several orders of magnitude higher than for the bulk material. Additionally we demonstrate the potential for device applications of such conducting nanoscale features.

  6. Structural transitions and multiferroic properties of high Ni-doped BiFeO3

    Science.gov (United States)

    Betancourt-Cantera, L. G.; Bolarín-Miró, A. M.; Cortés-Escobedo, C. A.; Hernández-Cruz, L. E.; Sánchez-De Jesús, F.

    2018-06-01

    Nickel doped bismuth ferrite powders, BiFe1-x NixO3 (0 ≤ x ≤ 0.5), were synthesized by high-energy ball milling followed by an annealing at 700 °C. A detailed study about the substitution of Fe3+ by Ni2+ on the crystal structure and multiferroic properties is presented. The X-ray diffraction patterns reveal the formation of rhombohedral structure with small amounts of Bi2Fe4O9 as a secondary phase for x behavior indicates the frustration of the G-antiferromagnetic order typical of the un-doped BiFeO3, caused by the presence of small amounts of Ni2+ (x Behavior modifications of electrical conductivity, permittivity and dielectric loss versus frequency are related with crystal structure transformations, when nickel concentration is increased.

  7. Ferroelectric and electrical characterization of multiferroic BiFeO3 at the single nanoparticle level

    Science.gov (United States)

    Vasudevan, R. K.; Bogle, K. A.; Kumar, A.; Jesse, S.; Magaraggia, R.; Stamps, R.; Ogale, S. B.; Potdar, H. S.; Nagarajan, V.

    2011-12-01

    Ferroelectric BiFeO3 (BFO) nanoparticles deposited on epitaxial substrates of SrRuO3 (SRO) and La1-xSrxMnO3 (LSMO) were studied using band excitation piezoresponse spectroscopy (BEPS), piezoresponse force microscopy (PFM), and ferromagnetic resonance (FMR). BEPS confirms that the nanoparticles are ferroelectric in nature. Switching behavior of nanoparticle clusters were studied and showed evidence for inhomogeneous switching. The dimensionality of domains within nanoparticles was found to be fractal in nature, with a dimensionality constant of ˜1.4, on par with ferroelectric BFO thin-films under 100 nm in thickness. Ferromagnetic resonance studies indicate BFO nanoparticles only weakly affect the magnetic response of LSMO.

  8. Magnetic Field Control of Cycloidal Domains and Electric Polarization in Multiferroic BiFeO3

    Science.gov (United States)

    Bordács, S.; Farkas, D. G.; White, J. S.; Cubitt, R.; DeBeer-Schmitt, L.; Ito, T.; Kézsmárki, I.

    2018-04-01

    The magnetic field induced rearrangement of the cycloidal spin structure in ferroelectric monodomain single crystals of the room-temperature multiferroic BiFeO3 is studied using small-angle neutron scattering. The cycloid propagation vectors are observed to rotate when magnetic fields applied perpendicular to the rhombohedral (polar) axis exceed a pinning threshold value of ˜5 T . In light of these experimental results, a phenomenological model is proposed that captures the rearrangement of the cycloidal domains, and we revisit the microscopic origin of the magnetoelectric effect. A new coupling between the magnetic anisotropy and the polarization is proposed that explains the recently discovered magnetoelectric polarization perpendicular to the rhombohedral axis.

  9. Effect of surface modification of BiFeO3 on the dielectric, ferroelectric, magneto-dielectric properties of polyvinylacetate/BiFeO3 nanocomposites

    Directory of Open Access Journals (Sweden)

    O. P. Bajpai

    2014-09-01

    Full Text Available Bismuth ferrite (BiFeO3 is considered as one of the most promising materials in the field of multiferroics. In this work, a simple green route as well as synthetic routes has been used for the preparation of pure phase BiFeO3. An extract of Calotropis Gigantea flower was used as a reaction medium in green route. In each case so formed BiFeO3 particles are of comparable quality. These particles are in the range of 50–60 nm and exhibit mixed morphology (viz., spherical and cubic as confirmed by TEM analysis. These pure phase BiFeO3 nanoparticles were first time surface modified effectively by mean of two silylating agent’s viz., tetraethyl orthosilicate (TEOS and (3-Aminopropyltriethoxysilane (APTES. Modified and unmodified BiFeO3 nanoparticles were efficiently introduced into polyvinylacetate (PVAc matrix. It has been shown that nanocomposite prepared by modified BiFeO3 comprise superior dispersion characteristics, improved ferroelectric properties and favorable magneto-dielectric properties along with excellent wettability in compare to nanocomposite prepared by unmodified BiFeO3. These preliminary results demonstrate possible applications of this type of nanocomposites particularly in the field of multiferroic coating and adhesives.

  10. A note on structural and dielectric properties of BiFeO3- PbTiO3 and BiFeO3- PbZrO3 composites

    International Nuclear Information System (INIS)

    Satpathy, S. K.; Mohanty, N. K.; Behera, A. K.; Behera, B.; Nayak, P.

    2015-01-01

    The composites of BiFeO 3 -PbTiO 3 (BF-PT) and BiFeO 3 -PbZrO 3 (BF-PZ) were prepared by mixed oxide method. Room temperature X-ray diffraction data confirms the rhombohedral and tetragonal crystal structure respectively. Dielectric constant of BF-PZ is found to give high value compared to BF-PT and hence, there is an increase value of ac conductivity for the former. Both the composites show negative temperature coefficient of resistance (NTCR) behavior. The activation energies of BF-PT and BF-PZ are found to be 0.35 eV and 0.53 eV respectively. The d 33 coefficients are found to be 2.0 and 2.1 pC/N for BF-PT and BF-PZ respectively

  11. Síntese e caracterização de perovesquites do sistema BiFeO3

    OpenAIRE

    Carvalho, Teresa Maria Tranchete de

    2007-01-01

    Dissertação de Mestrado em Física e Química para o Ensino, apresentada à Universidade de Trás-os-Montes e Alto Douro Os materiais multiferróicos, como o caso do BiFeO3, são bastante promissores em termos tecnológicos, possuindo uma potencial aplicação em sensores, memórias não voláteis e actuadores. A perovesquite BiFeO3 apresenta vantagens relativamente a outros compostos multiferróicos: elevada temperatura de Curie (TC=1100 K); elevada temperatura de Néel (TN=640 K); não contém chumbo...

  12. Investigation of electromagnetic properties of BiFeO3 by Time Differential Perturbed Angular Correlation (TDPAC) technique at ISOLDE

    CERN Document Server

    Efe, Ipek

    2017-01-01

    Time differential perturbed angular correlation (TDPAC) technique is one of the most sensitive techniques to study about the electric and magnetic fields at the individual lattice points. It benefits from the hyperfine interactions between the probe atom and its neighborhood. Multiferroic materials have been intensively studied to promote and understand the possibility of controlling magnetic properties by electric fields instead of magnetic fields which opens the path to faster, smaller, and more energy-efficient spintronic devices, such as memory elements, high-frequency magnetic devices, and micro-electro-mechanical systems, for data-storage technologies. BiFeO3 is one of the famous and important multiferroic materials since it shows both antiferromagnetic and ferroelectric behavior at room temperature. In this study, we report on the first time-differential perturbed angular correlation (TDPAC) measurements carried out on polycrystalline BiFeO3 samples using the nuclear probe 181Hf(181Ta) after implantati...

  13. Effects of magnetic annealing on structure and multiferroic properties of pure and dysprosium substituted BiFeO 3

    KAUST Repository

    Zhang, Shuxia; Yao, Yingbang; Chen, Yao; Wang, Dongliang; Zhang, Xianping; Awaji, Satoshi; Watanabe, Kazuo; Ma, Yanwei

    2012-01-01

    In this work, the effects of magnetic annealing on crystal structure and multiferroic properties of BiFeO 3 and Bi 0.85Dy 0.15FeO 3 have been investigated. It is found that the X-ray diffraction patterns of pure BiFeO 3 samples are obviously broadened after magnetic annealing, whereas those of Bi 0.85Dy 0.15FeO 3 samples are almost unchanged. Magnetic field annealing did not affect the magnetic properties of these two kinds of samples much. However, ferroelectric properties of the two materials exhibited different behaviors after magnetic field annealing. For pure BiFeO 3 samples, the remnant polarizations (P r) are suppressed; in contrast, for Bi 0.85Dy 0.15FeO 3 samples, P r is greatly enhanced. Possible mechanisms for the effects of magnetic field annealing have been discussed. © 2012 Elsevier B.V. All rights reserved.

  14. Accuracy and Transferability of Ab Initio Electronic Band Structure Calculations for Doped BiFeO3

    Science.gov (United States)

    Gebhardt, Julian; Rappe, Andrew M.

    2017-11-01

    BiFeO3 is a multiferroic material and, therefore, highly interesting with respect to future oxide electronics. In order to realize such devices, pn junctions need to be fabricated, which are currently impeded by the lack of successful p-type doping in this material. In order to guide the numerous research efforts in this field, we recently finished a comprehensive computational study, investigating the influence of many dopants onto the electronic structure of BiFeO3. In order to allow for this large scale ab initio study, the computational setup had to be accurate and efficient. Here we discuss the details of this assessment, showing that standard density-functional theory (DFT) yields good structural properties. The obtained electronic structure, however, suffers from well-known shortcomings. By comparing the conventional DFT results for alkali and alkaline-earth metal doping with more accurate hybrid-DFT calculations, we show that, in this case, the problems of standard DFT go beyond a simple systematic error. Conventional DFT shows bad transferability and the more reliable hybrid-DFT has to be chosen for a qualitatively correct prediction of doping induced changes in the electronic structure of BiFeO3.

  15. Effects of magnetic annealing on structure and multiferroic properties of pure and dysprosium substituted BiFeO 3

    KAUST Repository

    Zhang, Shuxia

    2012-07-01

    In this work, the effects of magnetic annealing on crystal structure and multiferroic properties of BiFeO 3 and Bi 0.85Dy 0.15FeO 3 have been investigated. It is found that the X-ray diffraction patterns of pure BiFeO 3 samples are obviously broadened after magnetic annealing, whereas those of Bi 0.85Dy 0.15FeO 3 samples are almost unchanged. Magnetic field annealing did not affect the magnetic properties of these two kinds of samples much. However, ferroelectric properties of the two materials exhibited different behaviors after magnetic field annealing. For pure BiFeO 3 samples, the remnant polarizations (P r) are suppressed; in contrast, for Bi 0.85Dy 0.15FeO 3 samples, P r is greatly enhanced. Possible mechanisms for the effects of magnetic field annealing have been discussed. © 2012 Elsevier B.V. All rights reserved.

  16. Influence of the collector and heat treatment in the structure of BiFeO_3 electrospun nanofibers

    International Nuclear Information System (INIS)

    Melo, G.H.F.; Santos, J.P.F.; Bretas, R.E.S.

    2016-01-01

    The objective of this work was to analyze the influence of the collector type and heat treatment on the morphology and crystalline phases of BiFeO_3 electrospun nanofibers. A solution containing (Fe(NO_3)_3_._9H_2O and Bi(NO_3)_3_._5H_2O) as precursors together with a polyvinylpyrrolidone solution was electrospun using 2.8KV/cm as electrical field. The collector type was however, changed (aluminum and glass). After the electrospinning, the as-spun nanofibers were submitted to two different heat treatments: one at 550°C and the other at 750°C, both during 2h. The collector type changed the morphology of the nanofibers; while in the glass collector, a non-woven mat of flat and rough nanofibers was obtained, in the aluminum collector, mats of circular and smooth nanofibers were obtained. The thermal treatment also changed the morphology and amount of crystalline phases; at 550°C, the nanofiber morphology was maintained and only one crystalline phase (BiFeO_3) was detected. On the other hand, at 750°C, flakes were obtained of two crystalline phases (BiFeO_3 and Bi_2Fe_4O_9). (author)

  17. Band-gap tuning and magnetic properties of heterovalent ions (Ba, Sr and Ca) substituted BiFeO_3 nanoparticles

    International Nuclear Information System (INIS)

    Chauhan, Sunil; Kumar, Manoj; Katyal, S. C.

    2016-01-01

    A Comparative study of heterovalent Ba, Sr and Ca ions substitution on the structural, vibrational, optical and magnetic properties of BiFeO_3 nanoparticles was carried out. The distorted rhombohedral structure was confirmed from both X-ray diffraction and Raman spectroscopy techniques in pure BiFeO_3 and Bi_0_._8_5A_0_._1_5FeO_3 (A= Ba, Sr and Ca) samples. UV-Visible spectroscopy results show that the band-gap of BiFeO_3 nanoparticles can be tuned by heterovalent ions substitution from 2.12 eV for BiFeO_3 to 2.10, 2.06 and 2.03 eV for Ca, Sr and Ba substituted BiFeO_3 nanoparticles respectively. The magnetic measurements indicate enhancement in magnetization for heterovalent A"2"+ substituted BiFeO_3 samples and the magnetization increases with increase of ionic radius of the substituted ions.

  18. Ferroelectric domain switching dynamics and memristive behaviors in BiFeO3-based magnetoelectric heterojunctions

    Science.gov (United States)

    Huang, Weichuan; Liu, Yukuai; Luo, Zhen; Hou, Chuangming; Zhao, Wenbo; Yin, Yuewei; Li, Xiaoguang

    2018-06-01

    The ferroelectric domain reversal dynamics and the corresponding resistance switching as well as the memristive behaviors in epitaxial BiFeO3 (BFO, ~150 nm) based multiferroic heterojunctions were systematically investigated. The ferroelectric domain reversal dynamics could be described by the nucleation-limited-switching model with the Lorentzian distribution of logarithmic domain-switching times. By engineering the domain states, multi and even continuously tunable resistances states, i.e. memristive states, could be non-volatilely achieved. The resistance switching speed can be as fast as 30 ns in the BFO-based multiferroic heterojunctions with a write voltage of ~20 V. By reducing the thickness of BFO, the La0.6Sr0.4MnO3/BFO (~5 nm)/La0.6Sr0.4MnO3 multiferroic tunnel junction (MFTJ) shows an even a quicker switching speed (20 ns) with a much lower operation voltage (~4 V). Importantly, the MFTJ exhibits a tunable interfacial magnetoelectric coupling related to the ferroelectric domain switching dynamics. These findings enrich the potential applications of multiferroic BFO based devices in high-speed, low-power, and high-density memories as well as future neuromorphic computational architectures.

  19. Influence of cobalt doping on structural and magnetic properties of BiFeO3 nanoparticles

    Science.gov (United States)

    Khan, U.; Adeela, N.; Javed, K.; Riaz, S.; Ali, H.; Iqbal, M.; Han, X. F.; Naseem, S.

    2015-11-01

    Nanocrystalline cobalt-doped bismuth ferrites with general formula of BiFe1- δ Co δ O3 (0 ≤ δ ≤ 0.1) have been synthesized using solution evaporation method. Structure and phase identification was performed with X-ray diffraction (XRD) technique. The results confirm the formation of rhombohedral-distorted Perovskite structure with R3c symmetry. A decrease in lattice parameters and an increase in X-ray density have been observed with increasing cobalt concentration in BiFeO3. Particle size determined by transmission electron microscope was in good agreement with XRD, i.e., 39 nm. Room-temperature coercivity and saturation magnetization of nanoparticles were increased up to 7.5 % of cobalt doping. Low-temperature magnetic measurements of selected sample showed increasing behavior in saturation magnetization, coercivity, effective magnetic moments, and anisotropy constant. An increase in coercivity with decrease in temperature followed theoretical model of Kneller's law, while modified Bloch's model was employed for saturation magnetization in temperature range of 5-300 K.

  20. Presence of glassy state and large exchange bias in nanocrystalline BiFeO3

    Science.gov (United States)

    Srivastav, Simant Kumar; Johari, Anima; Patel, S. K. S.; Gajbhiye, N. S.

    2017-11-01

    We investigated the static and dynamic aspects of the magnetic properties for single phase nanocrystalline BiFeO3 with average crystallite size of 35 nm. The frequency dependence of the peak is observed in the real part of ac susceptibility χ‧ac vs T measurement and described well by the Vogel-Fulcher law as well as the power law. These analyses indicated the existence of cluster glass state with significant interaction among the spin clusters and results in cluster-glass like cooperative freezing at low temperature. The influence of temperature and magnetic field cooling on the exchange bias effect is investigated. A training effect is also observed. We have reported a significantly high ZFC & FC exchange bias of 200 Oe & 450 Oe at 300 K and 900 Oe & 2100 Oe at 5 K. The obtained results are interpreted in the framework of core-shell model, where the core of the BFO nanoparticles shows antiferromagnetic behavior and surrounded by CG-like ferromagnetic (FM) shell associated to uncompensated surface spins.

  1. Magnetic ordering induced giant optical property change in tetragonal BiFeO3

    Science.gov (United States)

    Tong, Wen-Yi; Ding, Hang-Chen; Gong, Shi Jing; Wan, Xiangang; Duan, Chun-Gang

    2015-12-01

    Magnetic ordering could have significant influence on band structures, spin-dependent transport, and other important properties of materials. Its measurement, especially for the case of antiferromagnetic (AFM) ordering, however, is generally difficult to be achieved. Here we demonstrate the feasibility of magnetic ordering detection using a noncontact and nondestructive optical method. Taking the tetragonal BiFeO3 (BFO) as an example and combining density functional theory calculations with tight-binding models, we find that when BFO changes from C1-type to G-type AFM phase, the top of valance band shifts from the Z point to Γ point, which makes the original direct band gap become indirect. This can be explained by Slater-Koster parameters using the Harrison approach. The impact of magnetic ordering on band dispersion dramatically changes the optical properties. For the linear ones, the energy shift of the optical band gap could be as large as 0.4 eV. As for the nonlinear ones, the change is even larger. The second-harmonic generation coefficient d33 of G-AFM becomes more than 13 times smaller than that of C1-AFM case. Finally, we propose a practical way to distinguish the two AFM phases of BFO using the optical method, which is of great importance in next-generation information storage technologies.

  2. Calcination temperature influenced multiferroic properties of Ca-doped BiFeO3 nanoparticles

    International Nuclear Information System (INIS)

    Dhir, Gitanjali; Uniyal, Poonam; Verma, N. K.

    2015-01-01

    The influence of Ca-doping and particle size on structural, morphological and magnetic properties of BiFeO 3 nanoparticles has been studied. A sol-gel method was employed for the synthesis of nanoparticles and their particle size was tailored by varying the calcination temperature. Structural analysis revealed a rhombohedral distortion induced by Ca-substitution. The broadening of diffraction peaks with decreasing calcination temperature was indicative of reduction in crystallite size. The morphological analysis revealed the formation of agglomerated nanoparticles having average particle size ranging from 10-15 and 50-55 nm for C4 and C6, respectively. The agglomeration is attributed to high surface energy of nanoparticles. Ferromagnetism has been displayed by all the synthesized nanoparticles. Enhancement of saturation magnetization with Ca-substitution is attributed to suppression of spin cycloid structure by the reduction in size, lattice distortion and creation of oxygen vacancies by the substitution of divalent ion at trivalent site. Further, this value increases as a function of decreasing particle size. Strong particle size effects on magnetic properties of the synthesized nanoparticles are owed to increasing surface to volume ratio. All these observations are indicative of strong dependence of multiferroism on particle size

  3. Bulk photovoltaic effect in epitaxial (K, Nb) substituted BiFeO3 thin films

    Science.gov (United States)

    Agarwal, Radhe; Zheng, Fan; Sharma, Yogesh; Hong, Seungbum; Rappe, Andrew; Katiyar, Ram

    We studied the bulk photovoltaic effect in epitaxial (K, Nb) modified BiFeO3 (BKFNO) thin films using theoretical and experimental methods. Epitaxial BKFNO thin films were grown by pulsed laser deposition (PLD). First, we have performed first principles density function theory (DFT) using DFT +U method to calculate electronic band structure, including Hubbard-Ueff (Ueff =U-J) correction into Hamiltonian. The electronic band structure calculations showed a direct band gap at 1.9 eV and a defect level at 1.7 eV (in a 40 atom BKFNO supercell), sufficiently lower in comparison to the experimentally observed values. Furthermore, the piezoforce microscopy (PFM) measurements indicated the presence of striped polydomains in BKFNO thin films. Angle-resolved PFM measurements were also performed to find domain orientation and net polarization directions in these films. The experimental studies of photovoltaic effect in BKNFO films showed a short circuit current of 59 micro amp/cm2 and open circuit voltage of 0.78 V. We compared our experimental results with first principles shift current theory calculations of bulk photovoltaic effect (BPVE).The synergy between theory and experimental results provided a realization of significant role of BPVE in order to understand the photovoltaic mechanism in ferroelectrics.

  4. Photo catalytic BiFeO3 Nano fibrous Mats for Effective Water Treatment

    International Nuclear Information System (INIS)

    Shaibani, P.M.; Prashanthi, K.; Sohrabi, A.; Thundat, Th.

    2013-01-01

    One-dimensional BiFeO 3 (BFO) nano fibers fabricated by electro spinning of a solution of Nylon 6 /BFO followed by calcination were used for photo catalytic degradation of contaminants in water. The BFO fibers were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-Vis spectroscopy. The SEM images of the as-spun samples demonstrated the successful production of nano fibers and the SEM images of the samples after calcination confirmed the integrity of the continuous BFO nano fibers. XRD analysis indicated the dominant presence of BFO phase throughout the calcinated nano fibers. Photo catalytic activity of the nano fibers and their application in water purification were investigated against 4-chloro phenol (4CP) as a model water contaminant. The results of the UV-Vis spectroscopy show the degradation of the 4CP by means of the photo catalytic activity of the BFO nano fibers. The kinetics of the photodegradation of 4CP is believed to be governed by a pseudo-first-order kinetics model.

  5. Spatially Resolved Large Magnetization in Ultrathin BiFeO3

    KAUST Repository

    Guo, Er-Jia

    2017-06-19

    Here, a quantitative magnetic depth profile across the planar interfaces in BiFeO3 /La0.7 Sr0.3 MnO3 (BFO/LSMO) superlattices using polarized neutron reflectometry is obtained. An enhanced magnetization of 1.83 ± 0.16 μB /Fe in BFO layers is observed when they are interleaved between two manganite layers. The enhanced magnetic order in BFO persists up to 200 K. The depth dependence of magnetic moments in BFO/LSMO superlattices as a function of the BFO layer thickness is also explored. The results show the enhanced net magnetic moment in BFO from the LSMO/BFO interface extends 3-4 unit cells into BFO. The interior part of a thicker BFO layer has a much smaller magnetization, suggesting it still keeps the small canted AFM state. The results exclude charge transfer, intermixing, epitaxial strain, and octahedral rotations/tilts as dominating mechanisms for the large net magnetization in BFO. An explanation-one suggested by others previously and consistent with the observations-attributes the temperature dependence of the net magnetization of BFO to strong orbital hybridization between Fe and Mn across the interfaces. Such orbital reconstruction would establish an upper temperature limit for magnetic ordering of BFO.

  6. Electric Field Controlled Magnetism in BiFeO3/Ferromagnet Films

    Science.gov (United States)

    Holcomb, M. B.; Chu, Y. H.; Martin, L. W.; Gajek, M.; Seidel, J.; Ramesh, R.; Scholl, A.; Fraile-Rodriguez, A.

    2008-03-01

    Electric field control of magnetism is a hot technological topic at the moment due to its potential to revolutionize today's devices. Magnetoelectric materials, those having both electric and magnetic order and the potential for coupling between the two, are a promising avenue to approach electric control. BiFeO3, both a ferroelectric and an antiferromagnet, is the only single phase room temperature magnetoelectric that is currently known. In addition to other possibilities, its multiferroic nature has potential in the very active field of exchange bias, where an antiferromagnetic thin film pins the magnetic direction of an adjoining ferromagnetic layer. Since this antiferromagnet is electrically tunable, this coupling could allow electric-field control of the ferromagnetic magnetization. Direction determination of antiferromagnetic domains in BFO has recently been shown using linear and circular dichroism studies. Recently, this technique has been extended to look at the magnetic domains of a ferromagnetic grown on top of BFO. The clear magnetic changes induced by application of electric fields reveal the possibility of electric control.

  7. Functional Properties at Domain Walls in BiFeO3: Electrical, Magnetic, and Structural investigations

    Science.gov (United States)

    He, Qing; Yang, C.-H.; Yu, P.; Gajek, M.; Seidel, J.; Ramesh, R.; Wang, F.; Chu, Y.-H.; Martin, L. W.; Spaldin, N.; Rother, A.

    2009-03-01

    BiFeO3 (BFO) is a widely studied robust ferroelectric, antiferromagnetic multiferroic. Conducting-atomic force microscopy studies reveal the presence of enhanced conductivity at certain types of domain walls in BFO. We have completed detailed TEM studies of the physical structure at these domain walls as well as in-depth DFT calculations of the evolution of electronic structure at these domain walls. These studies reveal two major contributions to the observed conduction: the formation of an electrostatic potential at the domain walls as well as a structurally-driven change in the electronic structure (i.e., a lower band gap locally) at the domain walls. We will discuss the use of optical characterization techniques as a way of probing this change in electronic structure at domain walls as well as detailed IV characterization both in atmospheric and UHV environments. Finally, the evolution of magnetism at these domain walls has been studied through the use of photoemission measurements. Initial findings point to a significant change in the magnetic order at these domain walls in BFO.

  8. Enhancement of switching speed of BiFeO3 capacitors by magnetic fields

    Directory of Open Access Journals (Sweden)

    E. J. Guo

    2014-09-01

    Full Text Available The effect of a magnetic field on the ferroelectric switching kinetics of BiFeO3 (BFO capacitors with La0.8Ca0.2MnO3 (LCMO bottom electrode and Pt top contact has been investigated. We find a strong dependence of the remnant polarization and coercive field on the magnetic field. The switching time can be systematically tuned by magnetic field and reaches a tenfold reduction around the Curie temperature of LCMO at 4 T. We attribute this behavior to the splitting of the voltage drops across the BFO film and the LCMO bottom electrode, which can be strongly influenced by an external magnetic field due to the magnetoresistance. Further experiments on the BFO capacitors with SrRuO3 bottom electrodes show little magnetic field dependence of ferroelectric switching confirming our interpretation. Our results provide an efficient route to control the ferroelectric switching speed through the magnetic field, implying potential application in multifunctional devices.

  9. On the room temperature multiferroic BiFeO3: magnetic, dielectric and thermal properties

    Science.gov (United States)

    Lu, J.; Günther, A.; Schrettle, F.; Mayr, F.; Krohns, S.; Lunkenheimer, P.; Pimenov, A.; Travkin, V. D.; Mukhin, A. A.; Loidl, A.

    2010-06-01

    Magnetic dc susceptibility between 1.5 and 800 K, ac susceptibility and magnetization, thermodynamic properties, temperature dependence of radio and audio-wave dielectric constants and conductivity, contact-free dielectric constants at mm-wavelengths, as well as ferroelectric polarization are reported for single crystalline BiFeO3. A well developed anomaly in the magnetic susceptibility signals the onset of antiferromagnetic order close to 635 K. Beside this anomaly no further indications of phase or glass transitions are indicated in the magnetic dc and ac susceptibilities down to the lowest temperatures. The heat capacity has been measured from 2 K up to room temperature and significant contributions from magnon excitations have been detected. From the low-temperature heat capacity an anisotropy gap of the magnon modes of the order of 6 meV has been determined. The dielectric constants measured in standard two-point configuration are dominated by Maxwell-Wagner like effects for temperatures T > 300 K and frequencies below 1 MHz. At lower temperatures the temperature dependence of the dielectric constant and loss reveals no anomalies outside the experimental errors, indicating neither phase transitions nor strong spin phonon coupling. The temperature dependence of the dielectric constant was measured contact free at microwave frequencies. At room temperature the dielectric constant has an intrinsic value of 53. The loss is substantial and strongly frequency dependent indicating the predominance of hopping conductivity. Finally, in small thin samples we were able to measure the ferroelectric polarization between 10 and 200 K. The saturation polarization is of the order of 40 μC/cm2, comparable to reports in literature.

  10. Structural, electrical and multiferroic characteristics of thermo-mechanically fabricated BiFeO3-(BaSr)TiO3 solid solutions

    Science.gov (United States)

    Behera, C.; Choudhary, R. N. P.; Das, Piyush R.

    2018-05-01

    A solid solution consisting of two perovskite compounds (BiFeO3 and (BaSr)TiO3) of chemical composition (Bi1/2Ba1/4Sr1/4)(Fe1/2Ti1/2)O3 has been fabricated in the low dimensional regime by thermo-mechanical (ball milling and heating) approach. The effect of particle size on the structural, micro-structural, relative permittivity, switching (ferroelectric and magnetic) and conduction phenomena of the material has been studied using various experimental techniques such as x-rays diffraction, transmission and scanning electron microscopy, ferroelectric and magnetic hysteresis, dynamic magneto-electric coupling measurement and impedance spectroscopy techniques. All the above extracted properties are found to be particle size dependent. The first order magneto-electric coupling constant is found to be 2.56, 6.6 and 8.7 mV cm‑1.Oe for 30, 60 and 90 h milled calcined (hmc) sample respectively. As the above micro/nano-material with different particle size, has a high relative dielectric constant and low tangent loss, it can be used for some multifunctional devices including capacity energy storage device in nano-electronics.

  11. Optical spectroscopic study of multiferroic BiFeO3 and LuFe2O4

    Science.gov (United States)

    Xu, Xiaoshan

    2010-03-01

    Iron-based multiferroics such as BiFeO3 and LuFe2O4 exhibit the highest magnetic and ferroelectric ordering temperatures among known multiferroics. LuFe2O4 is a frustrated system with several phase transitions that result in electronically driven multiferroicity. To understand how this peculiar multiferroic mechanism correlates with magnetism, we studied electronic excitations by optical spectroscopy and other complementary techniques. We show that the charge order, which determines the dielectric properties, is due to the ``order by fluctuation'' mechanism, evidenced by the onset of charge fluctuation well below the charge ordering transition. We also find a low temperature monoclinic distortion driven by both temperature and magnetic field, indicating strong coupling between structure, magnetism and charge order. BiFeO3 is the only known single phase multiferroics with room temperature magnetism and ferroelectricity. To investigate the spin-charge coupling, we measured the optical properties of BiFeO3. We find that the absorption onset occurs due to on-site Fe^3+ excitations at 1.41 and 1.90 eV. Temperature and magnetic-field-induced spectral changes reveal complex interactions between on-site crystal-field and magnetic excitations in the form of magnon sidebands. The sensitivity of the magnon sidebands allows us to map out the magnetic-field temperature phase diagram which demonstrates optical evidence for spin spiral quenching above 20 T and suggests a spin domain reorientation near 10 T. Work done in collaboration with T.V. Brinzari, R.C. Rai, M. Angst, R.P. Hermann, A.D. Christianson, J.-W. Kim, Z. Islam, B.C. Sales, D. Mandrus, S. Lee, Y.H. Chu, L. W. Martin, A. Kumar, R. Ramesh, S.W. Cheong, S. McGill, and J.L. Musfeldt.

  12. Orthorhombic polar Nd-doped BiFeO3 thin film on MgO substrate

    International Nuclear Information System (INIS)

    Leontyev, I N; Janolin, P-E; Dkhil, B; Yuzyuk, Yu I; El-Marssi, M; Chernyshov, D; Dmitriev, V; Golovko, Yu I; Mukhortov, V M

    2011-01-01

    A Nd-doped BiFeO 3 thin film deposited on MgO substrate was studied by synchrotron diffraction. The ferroelectric nature of the film is proven by in-plane remanent polarization measurement. The highest possible symmetry of the film is determined to be orthorhombic, within the Fm2m space group. Such a structure is rotated by 45 0 with respect to the substrate and is consistent with tilts of oxygen octahedra doubling the unit cell. This polar structure presents a rather unusual strain-accommodation mechanism. (fast track communication)

  13. Specific features of nonlinear optical properties of Eu3+ doped BiFeO3 nanopowders near antiferromagnetic transition

    Science.gov (United States)

    El Bahraoui, T.; Sekkati, M.; Taibi, M.; Abd-Lefdil, M.; El-Naggar, A. M.; AlZayed, N. S.; Albassam, A. A.; Kityk, I. V.; Maciag, A.

    2016-01-01

    The monitoring of the Eu3+ doped BiFeO3 nanopowders was performed near the antiferromagnetic transformation by photoinduced optical second harmonic generation. As photoinduced laser beams we have used bicolor coherent excitations of the Er:glass laser emitting at 1540 nm with frequency repetition about 15 ns. The studies of the photoinduced SHG were performed versus temperature including the temperature range of ferromagnetic-ferroelectric transition (350 °C…390 °C). The optimal light polarization and intensity ratio were chosen; the sensitivity of the photoinduced SHG to the multiferroic phase transitions was explored.

  14. Interfacial effects on the electrical properties of multiferroic BiFeO3/Pt/Si thin film heterostructures

    International Nuclear Information System (INIS)

    Yakovlev, S.; Zekonyte, J.; Solterbeck, C.-H.; Es-Souni, M.

    2005-01-01

    Polycrystalline BiFeO 3 thin films of various thickness were fabricated on (111)Pt/Ti/SiO 2 /Si substrates via chemical solution deposition. The electrical properties were investigated using impedance and leakage current measurements. X-ray photoelectron spectroscopy (XPS) combined with Ar ion milling (depth profiling) was used to investigate elemental distribution near the electrode-film interface. It is shown that the dielectric constant depends on film thickness due to the presence of an interfacial film-electrode layer evidenced by XPS investigation. Direct current conductivity is found to be governed by Schottky and/or Poole-Frenkel mechanisms

  15. Superior Properties of Energetically Stable La2/3Sr1/3MnO3/Tetragonal BiFeO3 Multiferroic Superlattices

    KAUST Repository

    Feng, Nan; Mi, Wenbo; Wang, Xiaocha; Cheng, Yingchun; Schwingenschlö gl, Udo

    2015-01-01

    The superlattice of energetically stable La2/3Sr1/3MnO3 and tetragonal BiFeO3 is investigated by means of density functional theory. The superlattice as a whole exhibits a half-metallic character, as is desired for spintronic devices. The interfacial electronic states and exchange coupling are analyzed in details. We demonstrate that the interfacial O atoms play a key role in controlling the coupling. The higher ferroelectricity of tetragonal BiFeO3 and stronger response to the magnetic moment in La2/3Sr1/3MnO3/BiFeO3 superlattice show a strongly enhanced electric control of the magnetism as compared to the rhombohedral one. Therefore, it is particularly practical interest in the magnetoelectric controlled spintronic devices.

  16. Superior Properties of Energetically Stable La2/3Sr1/3MnO3/Tetragonal BiFeO3 Multiferroic Superlattices

    KAUST Repository

    Feng, Nan

    2015-04-30

    The superlattice of energetically stable La2/3Sr1/3MnO3 and tetragonal BiFeO3 is investigated by means of density functional theory. The superlattice as a whole exhibits a half-metallic character, as is desired for spintronic devices. The interfacial electronic states and exchange coupling are analyzed in details. We demonstrate that the interfacial O atoms play a key role in controlling the coupling. The higher ferroelectricity of tetragonal BiFeO3 and stronger response to the magnetic moment in La2/3Sr1/3MnO3/BiFeO3 superlattice show a strongly enhanced electric control of the magnetism as compared to the rhombohedral one. Therefore, it is particularly practical interest in the magnetoelectric controlled spintronic devices.

  17. Enhanced Photocurrent in BiFeO3 Materials by Coupling Temperature and Thermo-Phototronic Effects for Self-Powered Ultraviolet Photodetector System.

    Science.gov (United States)

    Qi, Jia; Ma, Nan; Ma, Xiaochen; Adelung, Rainer; Yang, Ya

    2018-04-25

    Ferroelectric materials can be utilized for fabricating photodetectors because of the photovoltaic effect. Enhancing the photovoltaic performance of ferroelectric materials is still a challenge. Here, a self-powered ultraviolet (UV) photodetector is designed based on the ferroelectric BiFeO 3 (BFO) material, exhibiting a high current/voltage response to 365 nm light in heating/cooling states. The photovoltaic performance of the BFO-based device can be well modulated by applying different temperature variations, where the output current and voltage can be enhanced by 60 and 75% in heating and cooling states, respectively. The enhancement mechanism of the photocurrent is associated with both temperature effect and thermo-phototronic effect in the photovoltaic process. Moreover, a 4 × 4 matrix photodetector array has been designed for detecting the 365 nm light distribution in the cooling state by utilizing photovoltage signals. This study clarifies the role of the temperature effect and the thermo-phototronic effect in the photovoltaic process of the BFO material and provides a feasible route for pushing forward practical applications of self-powered UV photodetectors.

  18. Thin film composites in the BiFeO3–Bi4Ti3O12 system obtained by an aqueous solution-gel deposition methodology

    Directory of Open Access Journals (Sweden)

    Carlos Gumiel

    2018-01-01

    Full Text Available Thin film multiferroic composites, with a high quantity of interfaces between the different materials, represent a more feasible alternative to single phase systems in which the multifunctional response is usually hampered due to intrinsic physical constraints. Nowadays some of these composites can be produced by applying deposition techniques such as PLD, CVD, MBE or the like, which allow a high degree of crystallographic control. However, despite their effectiveness, all these techniques also involve a high consumption of energy in terms of temperature and/or vacuum. Within this frame, the present contribution proposes a sustainable chemical solution deposition process to prepare thin films of the multiferroic BiFeO3–Bi4Ti3O12 composite system. More specifically an aqueous solution-gel plus spin-coating methodology is employed which also avoids the organic solvents typically used in a conventional sol–gel method, so further keeping an eye on the environmentally friendly conditions. Attempts are conducted that demonstrate how by systematically controlling the processing parameters it is possible to obtain thin film composites with a promising 3-3 type connectivity at temperatures as low as 600 °C.

  19. Thin film composites in the BiFeO3–Bi4Ti3O12 system obtained by an aqueous solution-gel deposition methodology

    International Nuclear Information System (INIS)

    Gumiel, C.; Vranken, T.; Bernardo, M.S.; Jardiel, T.; Hardy, A.; Van Bael, M.K.; Peiteado, M.

    2018-01-01

    Thin film multiferroic composites, with a high quantity of interfaces between the different materials, represent a more feasible alternative to single phase systems in which the multifunctional response is usually hampered due to intrinsic physical constraints. Nowadays some of these composites can be produced by applying deposition techniques such as PLD, CVD, MBE or the like, which allow a high degree of crystallographic control. However, despite their effectiveness, all these techniques also involve a high consumption of energy in terms of temperature and/or vacuum. Within this frame, the present contribution proposes a sustainable chemical solution deposition process to prepare thin films of the multiferroic BiFeO3–Bi4Ti3O12 composite system. More specifically an aqueous solution-gel plus spin-coating methodology is employed which also avoids the organic solvents typically used in a conventional sol–gel method, so further keeping an eye on the environmentally friendly conditions. Attempts are conducted that demonstrate how by systematically controlling the processing parameters it is possible to obtain thin film composites with a promising 3-3 type connectivity at temperatures as low as 600°C. [es

  20. Effects of (La, Sr) co-doping on electrical conduction and magnetic properties of BiFeO3 nanoparticles

    International Nuclear Information System (INIS)

    Liu Li; Wang Shouyu; Yin Zi; Zhang Chuang; Li Xiu; Yang Jiabin; Liu Weifang; Xu Xunling

    2016-01-01

    Multiferroic material as a photovoltaic material has gained considerable attention in recent years. Nanoparticles (NPs) La 0.1 Bi 0.9−x Sr x FeO y (LBSF, x = 0, 0.2, 0.4) with dopant Sr 2+ ions were synthesized by the sol–gel method. A systematic change in the crystal structure from rhombohedral to tetragonal upon increasing Sr doping was observed. There is an obvious change in the particle size from 180 nm to 50 nm with increasing Sr substitution into LBFO. It was found that Sr doping effectively narrows the band gap from ∼ 2.08 eV to ∼ 1.94 eV, while it leads to an apparent enhancement in the electrical conductivity of LBSF NPs, making a transition from insulator to semiconductor. This suggests an effective way to modulate the conductivity of BiFeO 3 -based multiferroic materials with pure phase by co-doping with La and Sr at the A sites of BiFeO 3 . (paper)

  1. Structural, magnetic and electric properties of Nd and Ni co-doped BiFeO3 materials

    Directory of Open Access Journals (Sweden)

    Dao Viet Thang

    2017-09-01

    Full Text Available Multiferroic Bi1−xNdxFe0.975Ni0.025O3 (x = 0.00, 0.05, 0.10, 0.125, and 0.15 (BNFNO and BiFeO3 (BFO materials were synthesized by a sol-gel method. Crystal structure, ferromagnetic and ferroelectric properties of the as-synthesized materials were investigated. Results showed that Nd3+ and Ni2+ co-doping affected to the electrical leakage, enhanced ferroelectric polarization and magnetization of BiFeO3. Co-doped sample with 12.5 mol% of Nd3+ and 2.5 mol% of Ni2+ exhibited an enhancement in both ferromagnetism and ferroelectric properties up to MS ~ 0.528 emu/g and PS ~ 18.35 μC/cm2 with applied electric field at 5 kV/cm, respectively. The origins of ferromagnetism and ferroelectricity enhancement were discussed in the paper.

  2. Structure and some magnetic properties of (BiFeO3x-(BaTiO31−x solid solutions prepared by solid-state sintering

    Directory of Open Access Journals (Sweden)

    Kowal Karol

    2015-03-01

    Full Text Available This paper presents the results of the study on structure and magnetic properties of the perovskite-type (BiFeO3x-(BaTiO31−x solid solutions. The samples differing in the chemical composition (x = 0.9, 0.8, and 0.7 were produced according to the conventional solid-state sintering method from the mixture of powders. Moreover, three different variants of the fabrication process differing in the temperatures and soaking time were applied. The results of X-ray diffraction (XRD, Mössbauer spectroscopy (MS, and vibrating sample magnetometry (VSM were collected and compared for the set of the investigated materials. The structural transformation from rhombohedral to cubic symmetry was observed for the samples with x = 0.7. With increasing of BaTiO3 concentration Mössbauer spectra become broadened reflecting various configurations of atoms around 57Fe probes. Moreover, gradual decreasing of the average hyperfine magnetic field and macroscopic magnetization were observed with x decreasing.

  3. Joining Chemical Pressure and Epitaxial Strain to Yield Y-doped BiFeO3 Thin Films with High Dielectric Response

    Science.gov (United States)

    Scarisoreanu, N. D.; Craciun, F.; Birjega, R.; Ion, V.; Teodorescu, V. S.; Ghica, C.; Negrea, R.; Dinescu, M.

    2016-05-01

    BiFeO3 is one of the most promising multiferroic materials but undergoes two major drawbacks: low dielectric susceptibility and high dielectric loss. Here we report high in-plane dielectric permittivity (ε’ ∼2500) and low dielectric loss (tan δ priced target.

  4. Thickness-dependent piezoelectric behaviour and dielectric properties of lanthanum modified BiFeO3 thin films

    Directory of Open Access Journals (Sweden)

    Glenda Biasotto

    2011-03-01

    Full Text Available Bi0.85La0.15FeO3 (BLFO thin films were deposited on Pt(111/Ti/SiO2 /Si substrates by the soft chemical method. Films with thicknesses ranging from 140 to 280 nm were grown on platinum coated silicon substrates at 500°C for 2 hours. The X-ray diffraction analysis of BLFO films evidenced a hexagonal structure over the entire thickness range investigated. The grain size of the film changes as the number of the layers increases, indicating thickness dependence. It is found that the piezoelectric response is strongly influenced by the film thickness. It is shown that the properties of BiFeO3 thin films, such as lattice parameter, dielectric permittivity, piezoeletric coefficient etc., are functions of misfit strains.

  5. Interfacial effects revealed by ultrafast relaxation dynamics in BiFeO 3 / YBa 2 Cu 3 O 7 bilayers

    KAUST Repository

    Springer, D.

    2016-02-12

    The temperature dependence of the relaxation dynamics in the bilayer thin film heterostructure composed of multiferroic BiFeO3 (BFO) and superconducting YBa2Cu3O7 (YBCO) grown on a (001) SrTiO3 substrate is studied by a time-resolved pump-probe technique, and compared with that of pure YBCO thin film grown under the same growth conditions. The superconductivity of YBCO is found to be retained in the heterostructure. We observe a speeding up of the YBCO recombination dynamics in the superconducting state of the heterostructure, and attribute it to the presence of weak ferromagnetism at the BFO/YBCO interface as observed in magnetization data. An extension of the Rothwarf-Taylor model is used to fit the ultrafast dynamics of BFO/YBCO, that models an increased quasiparticle occupation of the ferromagnetic interfacial layer in the superconducting state of YBCO.

  6. Effect of alkaline earth metal doping on thermal, optical, magnetic and dielectric properties of BiFeO3 nanoparticles

    International Nuclear Information System (INIS)

    Bhushan, B; Das, D; Basumallick, A; Bandopadhyay, S K; Vasanthacharya, N Y

    2009-01-01

    Substrate-free pure-phase BiFeO 3 (BFO) nanoparticles doped with alkaline earth metals (Ba, Sr and Ca) have been synthesized by a sol-gel route and their thermal, optical, dielectric and magnetic properties are discussed. The characteristic structural phase transitions of BFO nanoparticles are found to occur at much lower temperatures. A reduction of the Neel temperature has been observed in the doped samples in comparison with the pristine one, whereas the band gap shows a reverse trend. Iron was found to be only in the Fe 3+ valence state in all the doped samples. Magnetoelectric coupling is seen in our samples. Weak ferromagnetism is observed at room temperature in all of the doped and undoped BFO nanoparticles with the largest value of coercive field ∼1.78 kOe and saturation magnetization ∼2.38 emu g -1 for Ba and Ca doped BFO nanoparticles, respectively.

  7. Investigation of the annealing temperature effect on structural, morphology, dielectric and magnetic properties of BiFeO3 nanoparticles

    Science.gov (United States)

    Ranjbar, M.; Ghazi, M. E.; Izadifard, M.

    2018-06-01

    In this paper we have investigated the annealing temperature effect on the structure, morphology, dielectric and magnetic properties of sol-gel synthesized multiferroic BiFeO3 nanoparticles. X-ray diffraction spectroscopy revealed that all the samples have rhombohedrally distorted perovskite structure and the most pure BFO phase is obtained on the sample annealed at 800 °C. Field emission scanning electron microscopy (FESEM) revealed that increasing annealing temperature would increase the particle size. Decrease in dielectric constant was also observed by increasing annealing temperature. Vibrating sample method (VSM) analysis confirmed that samples annealed at 500-700 °C with particle size below the BFO's spiral spin structure length, have well saturated M-H curve and show ferromagnetic behavior.

  8. Multiferroic BiFeO3 thin films and nanodots grown on highly oriented pyrolytic graphite substrates

    Science.gov (United States)

    Shin, Hyun Wook; Son, Jong Yeog

    2017-12-01

    Multiferroic BiFeO3 (BFO) thin films and nanodots are deposited on highly oriented pyrolytic graphite (HOPG) substrates via a pulsed laser deposition technique, where the HOPG surface has a honeycomb lattice structure made of carbon atoms, similar to graphene. A graphene/BFO/HOPG capacitor exhibited multiferroic properties, namely ferroelectricity (a residual polarization of 26.8 μC/cm2) and ferromagnetism (a residual magnetization of 1.1 × 10-5 emu). The BFO thin film had high domain wall energies and demonstrated switching time of approximately 82 ns. An 8-nm BFO nanodot showed a typical piezoelectric hysteresis loop with an effective residual piezoelectric constant of approximately 110 pm/V and exhibited two clearly separated current curves depending on the ferroelectric polarization direction.

  9. Structural, magnetic, and ferroelectric properties of T-like cobalt-doped BiFeO3 thin films

    Science.gov (United States)

    Young, T.; Sharma, P.; Kim, D. H.; Ha, Thai Duy; Juang, Jenh-Yih; Chu, Y.-H.; Seidel, J.; Nagarajan, V.; Yasui, S.; Itoh, M.; Sando, D.

    2018-02-01

    We present a comprehensive study of the physical properties of epitaxial cobalt-doped BiFeO3 films ˜50 nm thick grown on (001) LaAlO3 substrates. X-ray diffraction and magnetic characterization demonstrate high quality purely tetragonal-like (T') phase films with no parasitic impurities. Remarkably, the step-and-terrace film surface morphology can be fully recovered following a local electric-field-induced rhombohedral-like to T' phase transformation. Local switching spectroscopy experiments confirm the ferroelectric switching to follow previously reported transition pathways. Critically, we show unequivocal evidence for conduction at domain walls between polarization variants in T'-like BFO, making this material system an attractive candidate for domain wall-based nanoelectronics.

  10. Room-temperature saturated ferroelectric polarization in BiFeO3 ceramics synthesized by rapid liquid phase sintering

    International Nuclear Information System (INIS)

    Wang, Y.P.; Zhou, L.; Zhang, M.F.; Chen, X.Y.; Liu, J.-M.; Liu, Z.G.

    2004-01-01

    Single-phased ferroelectromagnet BiFeO 3 ceramics with high resistivity were synthesized by a rapid liquid phase sintering technique. Saturated ferroelectric hysteresis loops were observed at room temperature in the ceramics sintered at 880 deg. C for 450 s. The spontaneous polarization, remnant polarization, and the coercive field are 8.9 μC/cm 2 , 4.0 μC/cm 2 , and 39 kV/cm, respectively, under an applied field of 100 kV/cm. It is proposed that the formation of Fe 2+ and an oxygen deficiency leading to the higher leakage can be greatly suppressed by the very high heating rate, short sintering period, and liquid phase sintering technique. The latter was also found effective in increasing the density of the ceramics. The sintering technique developed in this work is expected to be useful in synthesizing other ceramics from multivalent or volatile starting materials

  11. Interfacial effects revealed by ultrafast relaxation dynamics in BiFeO 3 / YBa 2 Cu 3 O 7 bilayers

    KAUST Repository

    Springer, D.; Nair, Saritha K.; He, Mi; Lu, C. L.; Cheong, S. A.; Wu, Tao; Panagopoulos, C.; Chia, Elbert E. M.; Zhu, Jian-Xin

    2016-01-01

    The temperature dependence of the relaxation dynamics in the bilayer thin film heterostructure composed of multiferroic BiFeO3 (BFO) and superconducting YBa2Cu3O7 (YBCO) grown on a (001) SrTiO3 substrate is studied by a time-resolved pump-probe technique, and compared with that of pure YBCO thin film grown under the same growth conditions. The superconductivity of YBCO is found to be retained in the heterostructure. We observe a speeding up of the YBCO recombination dynamics in the superconducting state of the heterostructure, and attribute it to the presence of weak ferromagnetism at the BFO/YBCO interface as observed in magnetization data. An extension of the Rothwarf-Taylor model is used to fit the ultrafast dynamics of BFO/YBCO, that models an increased quasiparticle occupation of the ferromagnetic interfacial layer in the superconducting state of YBCO.

  12. Annealing effect on the bipolar resistive switching behaviors of BiFeO3 thin films on LaNiO3-buffered Si substrates

    International Nuclear Information System (INIS)

    Chen Xinman; Zhang Hu; Ruan Kaibin; Shi Wangzhou

    2012-01-01

    Highlights: ► Annealing effect on the bipolar resistive switching behaviors of BiFeO 3 thin films with Pt/BiFeO 3 /LNO was reported. ► Rectification property was explained from the asymmetrical contact between top and bottom interfaces and the distinct oxygen vacancy density. ► The modification of Schottky-like barrier was suggested to be responsible for the resistance switching behaviors of Pt/BiFeO 3 /LNO devices. - Abstract: We reported the annealing effect on the electrical behaviors of BiFeO 3 thin films integrated on LaNiO 3 (LNO) layers buffered Si substrates by sol–gel spin-coating technique. All the BiFeO 3 thin films exhibit the reversible bipolar resistive switching behaviors with Pt/BiFeO 3 /LNO configuration. The electrical conduction mechanism of the devices was dominated by the Ohmic conduction in the low resistance state and trap-controlled space charged limited current in the high resistance state. Good diode-like rectification property was observed in device with BiFeO 3 film annealed at 500 °C, but vanished in device with BiFeO 3 film annealed at 600 °C. This was attributed to the asymmetrical contact between top and bottom interfaces as well as the distinct oxygen vacancy density verified by XPS. Furthermore, the modification of Schottky-like barrier due to the drift of oxygen vacancies was suggested to be responsible for the resistance switching behaviors of Pt/BiFeO 3 /LNO devices.

  13. Compound process fuel cycle concept

    International Nuclear Information System (INIS)

    Ikegami, Tetsuo

    2005-01-01

    Mass flow of light water reactor spent fuel for a newly proposed nuclear fuel cycle concept 'Compound Process Fuel Cycle' has been studied in order to assess the capacity of the concept for accepting light water reactor spent fuels, taking an example for boiling water reactor mixed oxide spent fuel of 60 GWd/t burn-up and for a fast reactor core of 3 GW thermal output. The acceptable heavy metal of boiling water reactor mixed oxide spent fuel is about 3.7 t/y/reactor while the burn-up of the recycled fuel is about 160 GWd/t and about 1.6 t/y reactor with the recycled fuel burn-up of about 300 GWd/t, in the case of 2 times recycle and 4 times recycle respectively. The compound process fuel cycle concept has such flexibility that it can accept so much light water reactor spent fuels as to suppress the light water reactor spent fuel pile-up if not so high fuel burn-up is expected, and can aim at high fuel burn-up if the light water reactor spent fuel pile-up is not so much. Following distinctive features of the concept have also been revealed. A sort of ideal utilization of boiling water reactor mixed oxide spent fuel might be achieved through this concept, since both plutonium and minor actinide reach equilibrium state beyond 2 times recycle. Changes of the reactivity coefficients during recycles are mild, giving roughly same level of reactivity coefficients as the conventional large scale fast breeder core. Both the radio-activity and the heat generation after 4 year cooling and after 4 times recycle are less than 2.5 times of those of the pre recycle fuel. (author)

  14. Unusual continuous dual absorption peaks in Ca-doped BiFeO3 nanostructures for broadened microwave absorption

    Science.gov (United States)

    Li, Zhong-Jun; Hou, Zhi-Ling; Song, Wei-Li; Liu, Xing-Da; Cao, Wen-Qiang; Shao, Xiao-Hong; Cao, Mao-Sheng

    2016-05-01

    Electromagnetic absorption materials have received increasing attention owing to their wide applications in aerospace, communication and the electronics industry, and multiferroic materials with both polarization and magnetic properties are considered promising ceramics for microwave absorption application. However, the insufficient absorption intensity coupled with the narrow effective absorption bandwidth has limited the development of high-performance multiferroic materials for practical microwave absorption. To address such issues, in the present work, we utilize interfacial engineering in BiFeO3 nanoparticles via Ca doping, with the purpose of tailoring the phase boundary. Upon Ca-substitution, the co-existence of both R3c and P4mm phases has been confirmed to massively enhance both dielectric and magnetic properties via manipulating the phase boundary and the destruction of the spiral spin structure. Unlike the commonly reported magnetic/dielectric hybrid microwave absorption composites, Bi0.95Ca0.05FeO3 has been found to deliver unusual continuous dual absorption peaks at a small thickness (1.56 mm), which has remarkably broadened the effective absorption bandwidth (8.7-12.1 GHz). The fundamental mechanisms based on the phase boundary engineering have been discussed, suggesting a novel platform for designing advanced multiferroic materials with wide applications.Electromagnetic absorption materials have received increasing attention owing to their wide applications in aerospace, communication and the electronics industry, and multiferroic materials with both polarization and magnetic properties are considered promising ceramics for microwave absorption application. However, the insufficient absorption intensity coupled with the narrow effective absorption bandwidth has limited the development of high-performance multiferroic materials for practical microwave absorption. To address such issues, in the present work, we utilize interfacial engineering in BiFeO3 nanoparticles via Ca doping, with the purpose of tailoring the phase boundary. Upon Ca-substitution, the co-existence of both R3c and P4mm phases has been confirmed to massively enhance both dielectric and magnetic properties via manipulating the phase boundary and the destruction of the spiral spin structure. Unlike the commonly reported magnetic/dielectric hybrid microwave absorption composites, Bi0.95Ca0.05FeO3 has been found to deliver unusual continuous dual absorption peaks at a small thickness (1.56 mm), which has remarkably broadened the effective absorption bandwidth (8.7-12.1 GHz). The fundamental mechanisms based on the phase boundary engineering have been discussed, suggesting a novel platform for designing advanced multiferroic materials with wide applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr00223d

  15. BiFeO3-doped (Na0.5K0.5NbO3 lead-free piezoelectric ceramics

    Directory of Open Access Journals (Sweden)

    Xueyi Sun et al

    2008-01-01

    Full Text Available Lead-free piezoelectric ceramics (1−x(Na0.5K0.5NbO3-xBiFeO3 (x=0~0.07 were synthesized by the solid-state reaction. Differential scanning calorimetry (DSC measurements revealed that an increase in the amount of BiFeO3 dopant resulted in a decrease in the orthorhombic-tetragonal and tetragonal-cubic phase transition temperature of the material. One percent BiFeO3 additive suppressed grain growth, which not only benefits the sintering of ceramics but also enhances the piezoelectric and ferroelectric properties, where d33=145pC/N, kp=0.31, Qm=80, Pr=11.3 μC cm−2 and Ec=16.5 kV cm−1. As xBF>0.01, both piezoelectric and ferroelectric properties decreased rapidly with an increasing amount of dopant.

  16. First-principles approach to the dynamic magnetoelectric couplings for the non-reciprocal directional dichroism in BiFeO3

    International Nuclear Information System (INIS)

    Lee, Jun Hee; Fishman, Randy S; Kézsmáki, István

    2016-01-01

    Due to the complicated magnetic and crystallographic structures of BiFeO 3 , its magnetoelectric (ME) couplings and microscopic model Hamiltonian remain poorly understood. By employing a first-principles approach, we uncover all possible ME couplings associated with the spin-current (SC) and exchange-striction (ES) polarizations, and construct an appropriate Hamiltonian for the long-range spin-cycloid in BiFeO 3 . First-principles calculations are used to understand the microscopic origins of the ME couplings. We find that inversion symmetries broken by ferroelectric and antiferroelectric distortions induce the SC and the ES polarizations, which cooperatively produce the dynamic ME effects in BiFeO 3 . A model motivated by first principles reproduces the absorption difference of counter-propagating light beams called non-reciprocal directional dichroism. The current paper focuses on the spin-driven (SD) polarizations produced by a dynamic electric field, i.e. the dynamic ME couplings. Due to the inertial properties of Fe, the dynamic SD polarizations differ significantly from the static SD polarizations. Our systematic approach can be generally applied to any multiferroic material, laying the foundation for revealing hidden ME couplings on the atomic scale and for exploiting optical ME effects in the next generation of technological devices such as optical diodes. (paper)

  17. Magnetic and dielectric properties of alkaline earth Ca2+ and Ba2+ ions co-doped BiFeO3 nanoparticles

    International Nuclear Information System (INIS)

    Yang, C.; Liu, C.Z.; Wang, C.M.; Zhang, W.G.; Jiang, J.S.

    2012-01-01

    Ca 2+ and Ba 2+ ions co-doped BiFeO 3 nanoparticles, Bi 0.8 Ca 0.2−x Ba x FeO 3 (x=0–0.20), were prepared by a sol–gel method. The phase structure, grain size, dielectric and magnetic properties of the prepared samples were investigated. The results showed that the lattice structure of the nanoparticles transformed from rhombohedral (x=0) to orthorhombic (x=0.07–0.19) and then to tetragonal (x=0.20) with x increased. The dielectric properties of the nanoparticles were affected by the properties of the substitutional ions as well as the crystalline structure of the samples. The magnetic properties of the nanoparticles were greatly improved and the T N of the nanoparticles was obviously increased. All the Ca 2+ and Ba 2+ ions co-doped BiFeO 3 nanoparticles presented the high ratio of M r /M from 0.527 to 0.571 and large coercivity from 4.335 to 5.163 KOe. - Highlights: ► Ca 2+ and Ba 2+ ions co-doped BiFeO 3 nanoparticles were prepared using a sol–gel method. ► The magnetic properties of the nanoparticles are greatly improved. ► The Neel temperature (T N ) of the nanoparticles is greatly increased. ► Doped ions and crystal structure affect the dielectric properties of the nanoparticles.

  18. Gadolinium substitution induced defect restructuring in multiferroic BiFeO3: case study by positron annihilation spectroscopy

    Science.gov (United States)

    Mukherjee, A.; Banerjee, M.; Basu, S.; Nambissan, P. M. G.; Pal, M.

    2013-12-01

    Positron annihilation spectroscopy (PAS) comprising of the measurements of positron lifetime and coincidence Doppler broadening spectra has been carried out to understand and monitor the evolution of the vacancy-type defects arising from the ionic deficiencies at lattice points of the multiferroic perovskite bismuth ferrite (BiFeO3) doped with 1, 5 and 10 at% gadolinium (Gd3+) ions. Negatively charged defects in the form of Bi3+ monovacancies (V_{Bi}^{3-} ) were present in the undoped nanocrystallites, which strongly trapped positrons. During the successive doping by Gd3+ ions, the positron trapping efficiency decreased while the doped ions combined with the vacancies to form complexes, which became neutral. A fraction of the positrons got annihilated at the crystallite surfaces too, being evident from the very large positron lifetimes obtained and confirming the nano-size-specific characteristics of the samples. Further, the intercrystallite regions provided favourable sites for orthopositronium formation, although in minute concentrations. The dopant ion-complex formation was also depicted clearly by the defect characteristic S-W plot. Also, the large change of electrical resistivity with Gd concentration has been explained nicely by invoking the defect information from the PAS study. The study has demonstrated the usefulness of an excellent method of defect identification in such a novel material system, which is vital information for exploiting them for further technological applications.

  19. Optical Diode Effect at Spin-Wave Excitations of the Room-Temperature Multiferroic BiFeO_{3}.

    Science.gov (United States)

    Kézsmárki, I; Nagel, U; Bordács, S; Fishman, R S; Lee, J H; Yi, Hee Taek; Cheong, S-W; Rõõm, T

    2015-09-18

    Multiferroics permit the magnetic control of the electric polarization and the electric control of the magnetization. These static magnetoelectric (ME) effects are of enormous interest: The ability to read and write a magnetic state current-free by an electric voltage would provide a huge technological advantage. Dynamic or optical ME effects are equally interesting, because they give rise to unidirectional light propagation as recently observed in low-temperature multiferroics. This phenomenon, if realized at room temperature, would allow the development of optical diodes which transmit unpolarized light in one, but not in the opposite, direction. Here, we report strong unidirectional transmission in the room-temperature multiferroic BiFeO_{3} over the gigahertz-terahertz frequency range. The supporting theory attributes the observed unidirectional transmission to the spin-current-driven dynamic ME effect. These findings are an important step toward the realization of optical diodes, supplemented by the ability to switch the transmission direction with a magnetic or electric field.

  20. Ferroelectric BiFeO3as an Oxide Dye in Highly Tunable Mesoporous All-Oxide Photovoltaic Heterojunctions

    KAUST Repository

    Wang, Lingfei

    2016-10-12

    As potential photovoltaic materials, transition-metal oxides such as BiFeO3 (BFO) are capable of absorbing a substantial portion of solar light and incorporating ferroic orders into solar cells with enhanced performance. But the photovoltaic application of BFO has been hindered by low energy-conversion efficiency due to poor carrier transport and collection. In this work, a new approach of utilizing BFO as a light-absorbing sensitizer is developed to interface with charge-transporting TiO2 nanoparticles. This mesoporous all-oxide architecture, similar to that of dye-sensitized solar cells, can effectively facilitate the extraction of photocarriers. Under the standard AM1.5 (100 mW cm−2) irradiation, the optimized cell shows an open-circuit voltage of 0.67 V, which can be enhanced to 1.0 V by tailoring the bias history. A fill factor of 55% is achieved, which is much higher than those in previous reports on BFO-based photovoltaic devices. The results provide here a new viable approach toward developing highly tunable and stable photovoltaic devices based on ferroelectric transition-metal oxides.

  1. Unusual continuous dual absorption peaks in Ca-doped BiFeO3 nanostructures for broadened microwave absorption.

    Science.gov (United States)

    Li, Zhong-Jun; Hou, Zhi-Ling; Song, Wei-Li; Liu, Xing-Da; Cao, Wen-Qiang; Shao, Xiao-Hong; Cao, Mao-Sheng

    2016-05-21

    Electromagnetic absorption materials have received increasing attention owing to their wide applications in aerospace, communication and the electronics industry, and multiferroic materials with both polarization and magnetic properties are considered promising ceramics for microwave absorption application. However, the insufficient absorption intensity coupled with the narrow effective absorption bandwidth has limited the development of high-performance multiferroic materials for practical microwave absorption. To address such issues, in the present work, we utilize interfacial engineering in BiFeO3 nanoparticles via Ca doping, with the purpose of tailoring the phase boundary. Upon Ca-substitution, the co-existence of both R3c and P4mm phases has been confirmed to massively enhance both dielectric and magnetic properties via manipulating the phase boundary and the destruction of the spiral spin structure. Unlike the commonly reported magnetic/dielectric hybrid microwave absorption composites, Bi0.95Ca0.05FeO3 has been found to deliver unusual continuous dual absorption peaks at a small thickness (1.56 mm), which has remarkably broadened the effective absorption bandwidth (8.7-12.1 GHz). The fundamental mechanisms based on the phase boundary engineering have been discussed, suggesting a novel platform for designing advanced multiferroic materials with wide applications.

  2. Study on superstructure in ion co-doped BiFeO3 by using transmission electron microscopy

    Science.gov (United States)

    Pu, Shi-Zhou; Guo, Chao; Li, Mei-Ya; Chen, Zhen-Lian; Zou, Hua-Min

    2015-04-01

    La3+ and V5+ co-doped BiFeO3 ceramics are synthesized by rapid liquid sintering technique. The modulated structure in Bi0.85La0.15Fe0.97V0.03O3 is investigated by using transmission electron microscopy (TEM). Two kinds of superstructures are observed in the samples. One is the component modulated superstructure and twin-domain, which is generated by La3+ ordered substitution for Bi3+ and frequently appears. The chemical composition of the superstructure is explored by x-ray energy dispersive spectroscopy (EDS). The model of the ordered structure is proposed. Simulation based on the model is conducted. The second is the fluorite-type δ-Bi2O3 related superstructure. The relation between the ferroelectric property and the microstructure of the sample is also discussed. Project supported by the National Natural Science Foundation of China (Grant Nos. 51372174, 11074193, and 51132001) and the Fundamental Research Funds for the Central Universities.

  3. Ferroelectric BiFeO3 as an Oxide Dye in Highly Tunable Mesoporous All-Oxide Photovoltaic Heterojunctions.

    Science.gov (United States)

    Wang, Lingfei; Ma, He; Chang, Lei; Ma, Chun; Yuan, Guoliang; Wang, Junling; Wu, Tom

    2017-01-01

    As potential photovoltaic materials, transition-metal oxides such as BiFeO 3 (BFO) are capable of absorbing a substantial portion of solar light and incorporating ferroic orders into solar cells with enhanced performance. But the photovoltaic application of BFO has been hindered by low energy-conversion efficiency due to poor carrier transport and collection. In this work, a new approach of utilizing BFO as a light-absorbing sensitizer is developed to interface with charge-transporting TiO 2 nanoparticles. This mesoporous all-oxide architecture, similar to that of dye-sensitized solar cells, can effectively facilitate the extraction of photocarriers. Under the standard AM1.5 (100 mW cm -2 ) irradiation, the optimized cell shows an open-circuit voltage of 0.67 V, which can be enhanced to 1.0 V by tailoring the bias history. A fill factor of 55% is achieved, which is much higher than those in previous reports on BFO-based photovoltaic devices. The results provide here a new viable approach toward developing highly tunable and stable photovoltaic devices based on ferroelectric transition-metal oxides. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Excitation of spin waves in BiFeO3 multiferroic film by the slot line transducer

    Science.gov (United States)

    Korneev, V. I.; Popkov, A. F.; Solov'yov, S. V.

    2018-01-01

    Analysis of the efficiency of magnetoelectric excitation of spin-waves in BiFeO3 multiferroic films by a slot line is performed based on the solution of dynamic Ginzburg-Landau equations for the antiferromagnetic vector. The excitation efficiency is determined by the magnitude of the conversion coefficient of the electromagnetic wave to the spin wave by the slot line transducer or in other words, losses on conversion in the slot line. Calculations are made for a homogeneous antiferromagnetic state of the multiferroic in the presence of a sufficiently large magnetic field and for a spatially modulated spin state (SMSS) at zero magnetic field. It is shown that in the case of a homogeneous antiferromagnetic state, the losses on the excitation of spin waves exceed the excitation efficiency in the SMSS state; however, as the frequency approaches the spin excitation gap, it falls and becomes lower than in the SMSS state. Spin wave excitation in the presence of antiferromagnetic cycloid strongly depends on the relation of the slot width of the transducer to the cycloid periodicity and on the magnitude of the shift of the position of the transducer along the cycloid on its period. The usage of multiferroics for delay lines in the considered frequency range from 100 to 600 GHz requires significant reduction in conversion and propagation losses. More promising seems multiferroic usage in phase shifters and switches for this range.

  5. Pyroelectric properties and electrical conductivity in samarium doped BiFeO 3 ceramics

    KAUST Repository

    Yao, Yingbang; Liu, Wenchao; Mak, C. L.

    2012-01-01

    . This electrical conduction was attributed to oxygen vacancy existing in the samples. An activation energy of ∼0.7 eV for the conduction process was found to be irrespective of the Sm 3+ doping level. On the other hand, the magnetic Néel temperature (T N) decreased

  6. Nonvolatile resistive switching in metal/La-doped BiFeO3/Pt sandwiches.

    Science.gov (United States)

    Li, Mi; Zhuge, Fei; Zhu, Xiaojian; Yin, Kuibo; Wang, Jinzhi; Liu, Yiwei; He, Congli; Chen, Bin; Li, Run-Wei

    2010-10-22

    The resistive switching (RS) characteristics of a Bi(0.95)La(0.05)FeO(3) (La-BFO) film sandwiched between a Pt bottom electrode and top electrodes (TEs) made of Al, Ag, Cu, and Au have been studied. Devices with TEs made of Ag and Cu showed stable bipolar RS behaviors, whereas those with TEs made of Al and Au exhibited unstable bipolar RS. The Ag/La-BFO/Pt structure showed an on/off ratio of 10(2), a retention time > 10(5) s, and programming voltages TEs under a bias voltage. The maximum current before the reset process (on-to-off switching) was found to increase linearly with the current compliance applied during the set process (off-to-on switching).

  7. Crystal structure and Mössbauer effect in multiferroic 0.5BiFeO3-0.5Pb(Fe0.5Ta0.5O3 solid solution

    Directory of Open Access Journals (Sweden)

    Stoch Agata

    2017-06-01

    Full Text Available Multiferroic 0.5BiFeO3-0.5Pb(Fe0.5Ta0.5O3 solid solution is a material that exhibits ferroelectric and antiferromagnetic orderings in ambient temperature. The solid solution was obtained as a result of a conventional reaction in a solid state. The obtained material is a dense, fine-grained sinter whose surface was observed by scanning electron microscopy (SEM and stoichiometry was confirmed by energy dispersive X-ray spectroscopic (EDS analysis. According to the X-ray powder diffraction (XRD measurements, the main phase is R3c space group with admixture of Pm-3m regular phase. Small contribution of pyrochlore-like phase was also observed. Mössbauer spectroscopy suggested random distribution of Fe3+/Ta5+ cations in the B sites of ABO3 compound. Reduction of the magnetic hyperfine field with an increase in the substitution of Ta5+ in Fe3+ neighbourhood was also observed.

  8. First-principles approach to the dynamic magnetoelectric couplings for the non-reciprocal directional dichroism in BiFeO3

    Science.gov (United States)

    Lee, Jun Hee; Kézsmáki, István; Fishman, Randy S.

    2016-04-01

    Due to the complicated magnetic and crystallographic structures of BiFeO3, its magnetoelectric (ME) couplings and microscopic model Hamiltonian remain poorly understood. By employing a first-principles approach, we uncover all possible ME couplings associated with the spin-current (SC) and exchange-striction (ES) polarizations, and construct an appropriate Hamiltonian for the long-range spin-cycloid in BiFeO3. First-principles calculations are used to understand the microscopic origins of the ME couplings. We find that inversion symmetries broken by ferroelectric and antiferroelectric distortions induce the SC and the ES polarizations, which cooperatively produce the dynamic ME effects in BiFeO3. A model motivated by first principles reproduces the absorption difference of counter-propagating light beams called non-reciprocal directional dichroism. The current paper focuses on the spin-driven (SD) polarizations produced by a dynamic electric field, i.e. the dynamic ME couplings. Due to the inertial properties of Fe, the dynamic SD polarizations differ significantly from the static SD polarizations. Our systematic approach can be generally applied to any multiferroic material, laying the foundation for revealing hidden ME couplings on the atomic scale and for exploiting optical ME effects in the next generation of technological devices such as optical diodes. This manuscript has been written by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the US Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan.

  9. Influence of Co doping on structural, optical and magnetic properties of BiFeO3 films deposited on quartz substrates by sol-gel method

    Science.gov (United States)

    Peng, Lin; Deng, Hongmei; Tian, Jianjun; Ren, Qing; Peng, Cheng; Huang, Zhipeng; Yang, Pingxiong; Chu, Junhao

    2013-03-01

    Multiferroic BiFe1-xCoxO3 (x = 0, 0.03, 0.05, 0.1) thin films have been prepared on quartz substrates using a sol-gel technique. X-ray diffraction data confirms that Co atoms have been successfully incorporated into the host lattice. The scanning electron microscopy (SEM) exhibits that the surface morphologies of BiFe0.97Co0.03O3 and BiFe0.95Co0.05O3 thin films become more compact and uniform. With increasing Co dopant, the position of A1-1 and E-4 modes shift towards the lower wavenumber indicates that Co doping induces structural distortion of BiFeO3. With increasing Co composition, the fundamental absorption edges of BiFe1-xCoxO3 films show red shift. Furthermore, transmittance spectra demonstrates that the optical band gap of BiFe1-xCoxO3 films decreases from 2.66 eV to 2.53 eV with the increase of Co from x = 0 to 0.1. At the wavelength of 720 nm, the refractive index decreases and the extinction coefficient increases with increasing the amount of Co. Optical properties reveal that Co doping in BiFeO3 provides preliminary research for optoelectronic devices and infrared detectors. Compared with BiFeO3 prepared under similar conditions, the remanent magnetization Mr of BiFe1-xCoxO3 (x = 0.03, 0.05, 0.1) thin films significantly enhanced, which provides potential applications in information storage.

  10. Multivariate fractional Poisson processes and compound sums

    OpenAIRE

    Beghin, Luisa; Macci, Claudio

    2015-01-01

    In this paper we present multivariate space-time fractional Poisson processes by considering common random time-changes of a (finite-dimensional) vector of independent classical (non-fractional) Poisson processes. In some cases we also consider compound processes. We obtain some equations in terms of some suitable fractional derivatives and fractional difference operators, which provides the extension of known equations for the univariate processes.

  11. On statistical analysis of compound point process

    Czech Academy of Sciences Publication Activity Database

    Volf, Petr

    2006-01-01

    Roč. 35, 2-3 (2006), s. 389-396 ISSN 1026-597X R&D Projects: GA ČR(CZ) GA402/04/1294 Institutional research plan: CEZ:AV0Z10750506 Keywords : counting process * compound process * hazard function * Cox -model Subject RIV: BB - Applied Statistics, Operational Research

  12. Enhancement in magnetic and dielectric properties of La and Pr co substituted BiFeO3

    International Nuclear Information System (INIS)

    Srivastava, Amit; Singh, H.K.; Awana, V.P.S.; Srivastava, O.N.

    2013-01-01

    Highlights: ► Significant enhancement in magnetization of BiFeO 3 is found on La and Pr co substitution. ► It is correlated with structural phase transformation and nanosized crystallites. ► Dielectric losses strongly diminish with La and Pr co substitution. -- Abstract: This report underlines the systematic studies of crystalline structure, magnetic and ferroelectric properties of polycrystalline Bi 1−x−y La x Pr y FeO 3 ceramic samples, in which x changes continuously from 0 to 0.2 for y = 0 and y from 0 to 0.2 for x = 0.2. X-ray diffraction (XRD) patterns revealed that La and Pr substitution at Bi site in the ceramic eliminates the usual impurity phases completely. Rietveld refinement of the XRD patterns shows that the crystal structure changes gradually from Rhombohedral (R3c) to Orthorhombic (pbnm) with increasing La and Pr concentration. This transition has significant effects on the multiferroic properties of Bi 1−x−y La x Pr y FeO 3 ceramics. Substantial enhancement in magnetization of Bi 1−x−y La x Pr y FeO 3 has been observed and this is found to be correlated with the evolution of structural phase change with doping of Pr in samples having lanthanum concentration of x = 0.2. This leads to the suppression of helical spin order. However, the enhancement in magnetic behavior also takes place due to nanocrystallite nature of Bi 1−x−y La x Pr y FeO 3 (x = 0.2, y = 0.05–0.2). For the nanocrystallites having sizes lower than 62 nm, which is the period of spin cycloid, this spin configuration will get destroyed resulting in the enhancement of magnetization. The studies of microstructures employing SEM and TEM revealed that Bi 1−x−y La x Pr y FeO 3 consists of nano size grained microstructures. It is also found that dielectric constant and dielectric loss get improved by La and Pr co-substitution. The dielectric constant for x = 0.0, y = 0.0 is 81 which changes to 354 for x = 0.2, y = 0.15 at 100 Hz. Dielectric losses are strongly diminished from 0.960 for x = 0.0, y = 0.0, 0.321 for x = 0.2, y = 0.0 and to 0.20 for x = 0.2, y = 0.05 at 100 Hz. This improvement in dielectric properties is likely due to the changes of lattice parameters and suppression of oxygen vacancies caused by La and Pr co substitution

  13. Phonological Processes in Complex and Compound Words

    Directory of Open Access Journals (Sweden)

    Alieh Kord Zaferanlu Kambuziya

    2016-02-01

    Full Text Available Abstract This research at making a comparison between phonological processes in complex and compound Persian words. Data are gathered from a 40,000-word Persian dictionary. To catch some results, 4,034 complex words and 1,464 compound ones are chosen. To count the data, "excel" software is used. Some results of the research are: 1- "Insertion" is the usual phonological process in complex words. More than half of different insertions belongs to the consonant /g/. Then /y/ and // are in the second and the third order. The consonant /v/ has the least percentage of all. The most percentage of vowel insertion belongs to /e/. The vowels /a/ and /o/ are in the second and third order. Deletion in complex words can only be seen in consonant /t/ and vowel /e/. 2- The most frequent phonological processes in compounds is consonant deletion. In this process, seven different consonants including /t/, //, /m/, /r/, / ǰ/, /d, and /c/. The only deleted vowel is /e/. In both groups of complex and compound, /t/ deletion can be observed. A sequence of three consonants paves the way for the deletion of one of the consonants, if one of the sequences is a sonorant one like /n/, the deletion process rarely happens. 3- In complex words, consonant deletion causes a lighter syllable weight, whereas vowel deletion causes a heavier syllable weight. So, both of the processes lead to bi-moraic weight. 4- The production of bi-moraic syllable in Persian is preferable to Syllable Contact Law. So, Specific Rules have precedence to Universals. 5- Vowel insertion can be seen in both groups of complex and compound words. In complex words, /e/ insertion has the most fundamental part. The vowels /a/ and /o/ are in the second and third place. Whenever there are two sequences of ultra-heavy syllables. By vowel insertion, the first syllable is broken into two light syllables. The compounds that are influenced by vowel insertion, can be and are pronounced without any insertion

  14. Process for uranium recovery in phosphorus compounds

    International Nuclear Information System (INIS)

    Demarthe, J.M.; Solar, Serge.

    1980-01-01

    Process for uranium recovery in phosphorus compounds with an organic phase containing a dialkylphosphoric acid. A solubilizing agent constituted of an heavy alcohol or a phosphoric acid ester or a tertiary phosphine oxide or octanol-2, is added to the organic phase for solubilization of the uranium and ammonium dialkyl pyrophosphate [fr

  15. Process for production of a borohydride compound

    Science.gov (United States)

    Allen, Nathan Tait; Butterick, III, Robert; Chin, Arthur Achhing; Millar, Dean Michael; Molzahn, David Craig

    2014-08-19

    A process for production of a borohydride compound M(BH.sub.4).sub.y. The process has three steps. The first step combines a compound of formula (R.sup.1O).sub.yM with aluminum, hydrogen and a metallic catalyst containing at least one metal selected from the group consisting of titanium, zirconium, hafnium, niobium, vanadium, tantalum and iron to produce a compound of formula M(AlH.sub.3OR.sup.1).sub.y, wherein R.sup.1 is phenyl or phenyl substituted by at least one alkyl or alkoxy group; M is an alkali metal, Be or Mg; and y is one or two; wherein the catalyst is present at a level of at least 200 ppm based on weight of aluminum. The second step combines the compound of formula M(AlH.sub.3OR.sup.1).sub.y with a borate, boroxine or borazine compound to produce M(BH.sub.4).sub.y and a byproduct mixture containing alkali metal and aluminum aryloxides. The third step separates M(BH.sub.4).sub.y from the byproduct mixture.

  16. Enhancement of magnetic and ferroelectric properties of BiFeO3 by Er and transition element (Mn, Co) co-doping

    International Nuclear Information System (INIS)

    Han, Yumin; Mao, Weiwei; Quan, Chuye; Wang, Xingfu; Yang, Jianping; Yang, Tao; Li, Xing’ao

    2014-01-01

    Highlights: • BiFeO 3 , Bi 0.8 Er 0.2 FeO 3 , Bi 0.8 Er 0.2 Fe 0.9 Mn 0.1 O 3 and Bi 0.8 Er 0.2 Fe 0.9 Co 0.1 O 3 nanoparticles were prepared by sol–gel method. • The introduction of Er and Mn, Co into BiFeO 3 leads into a phase transition with reduced grain size. • The phase transformation combined with size reduction has significantly increased saturated polarization (Ps), remanent polarization (Pr) and saturated magnetization (Ms), remanent magnetization (Mr) behaviors of the doped samples with the same variation trend. • The formation of dipolar defect complexes (DDCs) in the doped samples may also contribute to the improved ferroelectric property. • Bi 0.8 Er 0.2 Fe 0.9 Mn 0.1 O 3 exhibits significantly improved ferroelectric and ferromagnetic properties. - Abstract: BiFeO 3 (BFO), Bi 0.8 Er 0.2 FeO 3 (BEFO), Bi 0.8 Er 0.2 Fe 0.9 Mn 0.1 O 3 (BEFMO) and Bi 0.8 Er 0.2 Fe 0.9 Co 0.1 O 3 (BEFCO) nanoparticles were prepared by sol–gel method having an average size of 200 nm for BFO, under100 nm for BEFO and under 60 nm for BEFMO and BEFCO. Phase transition from a rhombohedral symmetry (R3c) for BFO to an orthorhombic symmetry (Ibmm) for BEFO, BEFMO and BEFCO has been observed. The phase transformation combined with size reduction has significantly improved both ferroelectric and ferromagnetic behaviors of the doped samples in a similar way. The formation of dipolar defect complexes (DDCs) in the doped samples also contributes to the improved ferroelectric property with saturated polarization (Ps) of 0.375 μC/cm 2 and remanent polarization (Pr) of 0.244 μC/cm 2 for BEFMO. Size effect may also impact the simultaneously developed Pr for BEFMO and BEFCO. Owning to the interactions between the ferromagnetic and antiferromagnetic microdomains, improved saturated magnetization (Ms) and remanent magnetization (Mr) are also observed in BEFMO

  17. Dielectric and piezoelectric properties of BiFeO3 modified Bi0.5Na0.5TiO3-Bi0.5K0.5TiO3 lead-free piezoelectric ceramics

    International Nuclear Information System (INIS)

    Zhou Changrong; Liu Xinyu; Li Weizhou

    2008-01-01

    The (0.82 - x)Bi 0.5 Na 0.5 TiO 3 -0.18Bi 0.5 K 0.5 TiO 3 -xBiFeO 3 (x = 0-0.07) lead-free piezoelectric ceramics were fabricated by a conventional solid-state reaction method and the effect of BiFeO 3 addition on microstructure and electrical properties of the ceramics was investigated. The specimens with x ≤ 0.05 maintained a rhombohedral-tetragonal phase coexistence and changed into a rhombohedral phase when x > 0.05 in crystal structure. The addition of BiFeO 3 caused a promoted grain growth. All the specimens reveal a low-frequency dielectric dispersion in the frequency range of 40-1 MHz. The piezoelectric constant d 33 and the electromechanical coupling factor k p show an obvious improvement by the addition of small amount of BiFeO 3 , which shows optimum values of d 33 = 170 pC/N and k p = 0.366 at x = 0.03. Contrary to the enhancement of piezoelectric properties, Q m decreases with increasing BiFeO 3 content. The mechanisms of intrinsic and extrinsic contributions to the dielectric and piezoelectric responses have been proposed. Intrinsic contributions are from the relative ion/cation shift that preserves the ferroelectric crystal structure. The remaining extrinsic contributions are from the domain-wall motion and point defects

  18. Single crystal growth of 67%BiFeO3-33%BaTiO3 solution by the floating zone method

    Science.gov (United States)

    Rong, Y.; Zheng, H.; Krogstad, M. J.; Mitchell, J. F.; Phelan, D.

    2018-01-01

    The growth conditions and the resultant grain morphologies and phase purities from floating-zone growth of 67%BiFeO3-33%BaTiO3 (BF-33BT) single crystals are reported. We find two formidable challenges for the growth. First, a low-melting point constituent leads to a pre-melt zone in the feed-rod that adversely affects growth stability. Second, constitutional super-cooling (CSC), which was found to lead to dendritic and columnar features in the grain morphology, necessitates slow traveling rates during growth. Both challenges were addressed by modifications to the floating-zone furnace that steepened the temperature gradient at the melt-solid interfaces. Slow growth was also required to counter the effects of CSC. Single crystals with typical dimensions of hundreds of microns have been obtained which possess high quality and are suitable for detailed structural studies.

  19. Single crystal growth of 67%BiFeO 3 -33%BaTiO 3 solution by the floating zone method

    Energy Technology Data Exchange (ETDEWEB)

    Rong, Y.; Zheng, H.; Krogstad, M. J.; Mitchell, J. F.; Phelan, D.

    2018-01-01

    The growth conditions and the resultant grain morphologies and phase purities from floating-zone growth of 67%BiFeO3-33%BaTiO3 (BF-33BT) single crystals are reported. We find two formidable challenges for the growth. First, a low-melting point constituent leads to a pre-melt zone in the feed-rod that adversely affects growth stability. Second, constitutional super-cooling (CSC), which was found to lead to dendritic and columnar features in the grain morphology, necessitates slow traveling rates during growth. Both challenges were addressed by modifications to the floating-zone furnace that steepened the temperature gradient at the melt-solid interfaces. Slow growth was also required to counter the effects of CSC. Single crystals with typical dimensions of hundreds of microns have been obtained which possess high quality and are suitable for detailed structural studies.

  20. Electric-field switchable magnetization via the Dzyaloshinskii-Moriya interaction: FeTiO3 versus BiFeO3

    International Nuclear Information System (INIS)

    Ederer, Claude; Fennie, Craig J

    2008-01-01

    In this paper we review and discuss a mechanism for coupling between electric polarization and magnetization that can ultimately lead to electric-field switchable magnetization. The basic idea is that a ferroelectric distortion in an antiferromagnetic material can 'switch on' the Dzyaloshinskii-Moriya interaction which leads to a canting of the antiferromagnetic sublattice magnetizations, and thus to a net magnetization. This magnetization M-vector is coupled to the polarization P-vector via a trilinear free energy contribution of the form P-vector·(M-vectorxxL-vector), where L-vector is the antiferromagnetic order parameter. In particular, we discuss why such an invariant is present in R3c FeTiO 3 but not in the isostructural multiferroic BiFeO 3 . Finally, we construct symmetry groups that in general allow for this kind of ferroelectrically-induced weak ferromagnetism.

  1. Resistive switching properties of Ce and Mn co-doped BiFeO3 thin films for nonvolatile memory application

    Directory of Open Access Journals (Sweden)

    Zhenhua Tang

    2013-12-01

    Full Text Available The Ce and Mn co-doped BiFeO3 (BCFMO thin films were synthesized on Pt/Ti/SiO2/Si substrates using a sol-gel method. The unipolar resistive switching (URS and bipolar resistive switching (BRS behaviors were observed in the Pt/BCFMO/Pt device structure, which was attributed to the formation/rupture of metal filaments. The fabricated device exhibits a large ROFF/RON ratio (>80, long retention time (>105 s and low programming voltages (<1.5 V. Analysis of linear fitting current-voltage curves suggests that the space charge limited leakage current (SCLC and Schottky emission were observed as the conduction mechanisms of the devices.

  2. Evidence for oxygen vacancy or ferroelectric polarization induced switchable diode and photovoltaic effects in BiFeO3 based thin films

    International Nuclear Information System (INIS)

    Guo Yiping; Guo Bing; Dong Wen; Li Hua; Liu Hezhou

    2013-01-01

    The diode and photovoltaic effects of BiFeO 3 and Bi 0.9 Sr 0.1 FeO 3−δ polycrystalline thin films were investigated by poling the films with increased magnitude and alternating direction. It was found that both electromigration of oxygen vacancies and polarization flipping are able to induce switchable diode and photovoltaic effects. For the Bi 0.9 Sr 0.1 FeO 3−δ thin films with high oxygen vacancy concentration, reversibly switchable diode and photovoltaic effects can be observed due to the electromigration of oxygen vacancies under an electric field much lower than its coercive field. However, for the pure BiFeO 3 thin films with lower oxygen vacancy concentration, the reversibly switchable diode and photovoltaic effect is hard to detect until the occurrence of polarization flipping. The switchable diode and photovoltaic effects can be explained well using the concepts of Schottky-like barrier-to-Ohmic contacts resulting from the combination of oxygen vacancies and polarization. The sign of photocurrent could be independent of the direction of polarization when the modulation of the energy band induced by oxygen vacancies is large enough to offset that induced by polarization. The photovoltaic effect induced by the electromigration of oxygen vacancies is unstable due to the diffusion of oxygen vacancies or the recombination of oxygen vacancies with hopping electrons. Our work provides deep insights into the nature of diode and photovoltaic effects in ferroelectric films, and will facilitate the advanced design of switchable devices combining spintronic, electronic, and optical functionalities. (paper)

  3. Modifications in the rhombohedral degree of distortion and magnetic properties of Ba-doped BiFeO3 as a function of synthesis methodology

    International Nuclear Information System (INIS)

    Rojas-George, G.; Silva, J.; Castañeda, R.; Lardizábal, D.; Graeve, O.A.; Fuentes, L.; Reyes-Rojas, A.

    2014-01-01

    We present an analysis of crystallographic symmetry and the origin of the pseudo-cubic character of doped BiFeO 3 . Specifically, barium-doped bismuth ferrite, Bi 1−x Ba x FeO 3 (x = 0.05, 0.075, 0.1, 0.125), perovskite-type nanoparticles have been synthesized by implementing five modifications to the sol–gel technique (citric acid-assisted sol–gel method, ethylene glycol method, tartaric acid-assisted sol–gel method, polyvinyl alcohol–ethylene glycol method, and EDTA complexing sol–gel method) and their final pseudo-cubic character is discussed. The effect of the carboxylic groups and hydroxyl groups during synthesis is critical to obtain single phase BBFO. Fourier transform infrared spectroscopy and thermogravimetric analysis is used to study the decomposition and thermal behavior of the precursors and their relation to the final nanoparticle characteristics. X-ray diffraction analysis shows a single phase with symmetry changes for four of the five synthesis methodologies employed. Only the EDTA complexing sol–gel method, where EDTA is used as dissolver and chelating agent, is not satisfactory in all concentration ranges. Rietveld results suggest that the degree of distortion of the rhombohedral symmetry in the crystallized BiFeO 3 powders decreases 12% as a result of progressive substitution of Bi 3+ by Ba 2+ and that there is no shift from rhombohedral to tetragonal symmetry. Magnetization properties of samples with a low-distortion rhombohedral structure show higher magnetic saturation and remanent magnetization than samples with high-distortion rhombohedral structure. - Highlights: • Ba–BiFeO 3 : rhombohedral distortion degree is highly affected by the chemical method. • Rietveld results show no shift in BBFO from rhombohedral to tetragonal symmetry. • The low-distortion rhombohedral structure show higher magnetic saturation. • To stabilize a metal complex is necessary a balance between COOH − and OH − groups

  4. Alternative Forms of Compound Fractional Poisson Processes

    Directory of Open Access Journals (Sweden)

    Luisa Beghin

    2012-01-01

    Full Text Available We study here different fractional versions of the compound Poisson process. The fractionality is introduced in the counting process representing the number of jumps as well as in the density of the jumps themselves. The corresponding distributions are obtained explicitly and proved to be solution of fractional equations of order less than one. Only in the final case treated in this paper, where the number of jumps is given by the fractional-difference Poisson process defined in Orsingher and Polito (2012, we have a fractional driving equation, with respect to the time argument, with order greater than one. Moreover, in this case, the compound Poisson process is Markovian and this is also true for the corresponding limiting process. All the processes considered here are proved to be compositions of continuous time random walks with stable processes (or inverse stable subordinators. These subordinating relationships hold, not only in the limit, but also in the finite domain. In some cases the densities satisfy master equations which are the fractional analogues of the well-known Kolmogorov one.

  5. Cascaded processing in written compound word production

    Directory of Open Access Journals (Sweden)

    Raymond eBertram

    2015-04-01

    Full Text Available In this study we investigated the intricate interplay between central linguistic processing and peripheral motor processes during typewriting. Participants had to typewrite two-constituent (noun-noun Finnish compounds in response to picture presentation while their typing behavior was registered. As dependent measures we used writing onset time to assess what processes were completed before writing and inter-key intervals to assess what processes were going on during writing. It was found that writing onset time was determined by whole word frequency rather than constituent frequencies, indicating that compound words are retrieved as whole orthographic units before writing is initiated. In addition, we found that the length of the first syllable also affects writing onset time, indicating that the first syllable is fully prepared before writing commences. The inter-key interval results showed that linguistic planning is not fully ready before writing, but cascades into the motor execution phase. More specifically, inter-key intervals were largest at syllable and morpheme boundaries, supporting the view that additional linguistic planning takes place at these boundaries. Bigram and trigram frequency also affected inter-key intervals with shorter intervals corresponding to higher frequencies. This can be explained by stronger memory traces for frequently co-occurring letter sequences in the motor memory for typewriting. These frequency effects were even larger in the second than in the first constituent, indicating that low-level motor memory starts to become more important during the course of writing compound words. We discuss our results in the light of current models of morphological processing and written word production.

  6. Cascaded processing in written compound word production.

    Science.gov (United States)

    Bertram, Raymond; Tønnessen, Finn Egil; Strömqvist, Sven; Hyönä, Jukka; Niemi, Pekka

    2015-01-01

    In this study we investigated the intricate interplay between central linguistic processing and peripheral motor processes during typewriting. Participants had to typewrite two-constituent (noun-noun) Finnish compounds in response to picture presentation while their typing behavior was registered. As dependent measures we used writing onset time to assess what processes were completed before writing and inter-key intervals to assess what processes were going on during writing. It was found that writing onset time was determined by whole word frequency rather than constituent frequencies, indicating that compound words are retrieved as whole orthographic units before writing is initiated. In addition, we found that the length of the first syllable also affects writing onset time, indicating that the first syllable is fully prepared before writing commences. The inter-key interval results showed that linguistic planning is not fully ready before writing, but cascades into the motor execution phase. More specifically, inter-key intervals were largest at syllable and morpheme boundaries, supporting the view that additional linguistic planning takes place at these boundaries. Bigram and trigram frequency also affected inter-key intervals with shorter intervals corresponding to higher frequencies. This can be explained by stronger memory traces for frequently co-occurring letter sequences in the motor memory for typewriting. These frequency effects were even larger in the second than in the first constituent, indicating that low-level motor memory starts to become more important during the course of writing compound words. We discuss our results in the light of current models of morphological processing and written word production.

  7. Radiation processing of polyolefins and compounds

    International Nuclear Information System (INIS)

    Barlow, A.; Biggs, J.; Maringer, M.

    1977-01-01

    Many properties of polyethylene and its copolymers are enhanced by crosslinking. This can be accomplished through the use of either peroxides or radiation. Crosslinking with peroxides is performed at elevated temperatures generally under pressure; catalyst residues remain in the product which have an adverse effect on electrical and possibly other properties. Radiation crosslinking, on the other hand, is performed under ambient conditions, is essentially free of pollution and offers lower overall production costs due to increased processing speed. A cost analysis of the two crosslinking processes applied to wire and cable coating is included. The advantages of radiation curing can be negated by processing problems which lead to inadequate product properties. Problems are described which may be encountered in developing a flame retardant, radiation curable compound for wire and cable coating. Of particular concern is the generation of a microporous structure which is accentuated by the presence of flame retardant ingredients and the absence of pressure inherent to the peroxide curing process. The procedures involved in solving these problems are briefly described. (author)

  8. Evidence of sharp and diffuse domain walls in BiFeO3 by means of unit-cell-wise strain and polarization maps obtained with high resolution scanning transmission electron microscopy.

    Science.gov (United States)

    Lubk, A; Rossell, M D; Seidel, J; He, Q; Yang, S Y; Chu, Y H; Ramesh, R; Hÿtch, M J; Snoeck, E

    2012-07-27

    Domain walls (DWs) substantially influence a large number of applications involving ferroelectric materials due to their limited mobility when shifted during polarization switching. The discovery of greatly enhanced conduction at BiFeO(3) DWs has highlighted yet another role of DWs as a local material state with unique properties. However, the lack of precise information on the local atomic structure is still hampering microscopical understanding of DW properties. Here, we examine the atomic structure of BiFeO(3) 109° DWs with pm precision by a combination of high-angle annular dark-field scanning transmission electron microscopy and a dedicated structural analysis. By measuring simultaneously local polarization and strain, we provide direct experimental proof for the straight DW structure predicted by ab initio calculations as well as the recently proposed theory of diffuse DWs, thus resolving a long-standing discrepancy between experimentally measured and theoretically predicted DW mobilities.

  9. Structure and electrical properties of (La, Zn) Co-doped BiFeO3 thin films prepared by using chemical solution deposition

    Science.gov (United States)

    Kim, Y. J.; Kim, H. J.; Kim, J. W.; Raghavan, C. M.; Kim, S. S.

    2012-08-01

    We prepared pure BiFeO3 (BFO) and (Bi0.9La0.1)(Fe0.975Zn0.025)O3- δ (BLFZO) thin films on Pt(111)/Ti/SiO2/Si(100) substrates by using a chemical solution deposition method. Improved electrical properties were observed in the co-doped BLFZO thin film. The leakage current density of the BLFZO thin film was four orders of magnitude lower than that of the pure BFO, 4.17 × 10-7 A/cm2 at 100 kV/cm. The remnant polarization (2 P r ) and the coercive electric field (2 E c ) of the BLFZO thin film were 97 µC/cm2 and 903 kV/cm at an applied electric field of 972 kV/cm and at a frequency of 1 kHz, and the values decreased with increasing measurement frequency to 63 µC/cm2 and 679 kV/cm at 10 kHz, respectively. Also, after 1.44 × 1010 cycles, a better fatigue endurance was observed in the BLFZO thin film, which was 90% of its initial value. We also confirmed that the remnant polarization (2 P r ) and the coercive electric field (2 E c ) were fairly saturated above a measurement frequency of 15 kHz for the BLFZO thin film.

  10. Enhancement of the electrical properties of (Eu,Zn) co-doped BiFeO3 thin films prepared by using chemical solution deposition

    Science.gov (United States)

    Kim, Youn-Jang; Kim, Jin Won; Kim, Hae Jin; Kim, Sang Su

    2013-04-01

    We prepared pure BiFeO3 (BFO) and (Bi0.9Eu0.1)(Fe0.975Zn0.025)O3-δ (BEFZO) thin films on Pt(111)/Ti/SiO2/Si(100) substrates by using a chemical solution deposition method. Improved electrical properties were observed in the co-doped BEFZO thin film. The leakage current density of the BEFZO thin film was three orders of magnitude lower than that of the pure BFO, 3.93 × 10-6 A/cm2 at 100 kV/cm. The remnant polarization (2 P r ) and the coercive electric field (2 E c ) of the BEFZO thin film were 42 µC/cm2 and 898 kV/cm at an applied electric field of 1000 kV/cm and at a frequency of 1 kHz and the values decreased with increasing measurement frequency to 18 µC/cm2 and 866 kV/cm at 10 kHz, respectively. Also, the fatigue endurances were evaluated at peak voltages of 8-10 V after 1.44 × 1010 cycles in the BEFZO thin films and were 70 ˜ 90% of the initial values. We also confirmed that the 2 P r was fairly saturated at measurement frequency about 30 kHz for the BEFZO thin film.

  11. Multiferroic properties of BiFeO3/Bi4Ti3O12 double-layered thin films fabricated by chemical solution deposition

    International Nuclear Information System (INIS)

    Yi, Seung Woo; Kim, Sang Su; Kim, Jin Won; Jo, Hyun Kyung; Do, Dalhyun; Kim, Won-Jeong

    2009-01-01

    Multiferroic BiFeO 3 /Bi 4 Ti 3 O 12 (BFO/BTO) double-layered film was fabricated on a Pt(111)/Ti/SiO 2 /Si(100) substrate by a chemical solution deposition method. The effect of an interfacial BTO layer on electrical and magnetic properties of BFO was investigated by comparing those of pure BFO and BTO films prepared by the same condition. The X-ray diffraction result showed that no additional phase was formed in the double-layered film, except BFO and BTO phases. The remnant polarization (2P r ) of the double-layered film capacitor was 100 μC/cm 2 at 250 kV/cm, which is much larger than that of the pure BFO film capacitor. The magnetization-magnetic field hysteresis loop revealed weak ferromagnetic response with remnant magnetization (2M r ) of 0.4 kA/m. The values of dielectric constant and dielectric loss of the double-layered film capacitor were 240 and 0.03 at 100 kHz, respectively. Leakage current density measured from the double-layered film capacitor was 6.1 x 10 -7 A/cm 2 at 50 kV/cm, which is lower than the pure BFO and BTO film capacitors.

  12. Stress induced enhanced polarization in multilayer BiFeO3/BaTiO3 structure with improved energy storage properties

    Directory of Open Access Journals (Sweden)

    Savita Sharma

    2015-10-01

    Full Text Available Present work reports the fabrication of a multilayer (5-layer structure of BiFeO3(BFO/BaTiO3(BTO using spin-coating technique. The crystallographic structure, surface morphology and ferroelectric behavior of multilayer structure in metal-ferroelectric-metal capacitor have been studied. Le-Bail refinement of X-ray diffraction data revealed the formation of polycrystalline pure perovskite phase with induced stress. The values of remnant (Pr and saturation polarization (Ps for BFO/BTO multilayer structure are found to be 38.14 μC/cm2 and 71.54 μC/cm2 respectively, which are much higher than the corresponding values reported for bare BFO thin film. A large value of dielectric constant of 187 has been obtained for multilayer structure with a low leakage current density of 1.09 × 10−7 A/cm2 at applied bias of 10 V. The BFO/BTO multilayer structure favors the enhanced energy storage capacity as compared to bare BFO thin film with improved values of energy-density and charge-discharge efficiency as 121 mJ/cm3 and 59% respectively, suggesting futuristic energy storage applications.

  13. Coexistence of room temperature ferroelectricity and ferrimagnetism in multiferroic BiFeO3-Bi0.5Na0.5TiO3 solid solution

    International Nuclear Information System (INIS)

    Tian, Z.M.; Wang, C.H.; Yuan, S.L.; Wu, M.S.; Ma, Z.Z.; Duan, H.N.; Chen, L.

    2011-01-01

    Highlights: → In this study, the coexistence of ferroelectrics and ferrimagnetism have been observed at room temperature for the (1 - x)BiFeO 3 -xBi 0.5 Na 0.5 TiO 3 (x = 0.37) solid solutions. → X-ray diffraction and Raman spectroscopy measurements show a single-phase perovskite structure with no impurities identified. → A magnetic transition from paramagnetic (PM) to ferrimagnetic (Ferri) ordering is observed for the solution with Curie temperature T C ∼ 330 K. - Abstract: The structure, ferroelectric and magnetic properties of (1 - x)BiFeO 3 -xBi 0.5 Na 0.5 TiO 3 (x = 0.37) solid solution fabricated by a sol-gel method have been investigated. X-ray diffraction and Raman spectroscopy measurements show a single-phase perovskite structure with no impurities identified. Compared with pure BiFeO 3 , the coexistence of ferroelectricity and ferrimagnetism have been observed at room temperature for the solution with remnant polarization P r = 1.41 μC/cm 2 and remnant magnetization M r = 0.054 emu/g. Importantly, a magnetic transition from ferrimagnetic (FM) ordering to paramagnetic (PM) state is observed, with Curie temperature T C ∼ 330 K, being explained in terms of the suppression of cycloid spin configuration by the structural distortion.

  14. Control of oxygen octahedral rotation in BiFeO3 films using modulation of SrRuO3 bottom electrode layer

    Science.gov (United States)

    Lee, Sungsu; Jo, Ji Young

    2015-03-01

    Oxygen octahedral rotation of multiferroic BiFeO3 (BFO) has attracted great attention due to changes of electrical and magnetic properties. Coupling of octahedral rotation in BFO-bottom electrode layer interface remains unexplored. Recently, there have been reported the control of octahedral rotation in SrRuO3 (SRO) film on SrTiO3 (001) substrate by coherently controlling the oxygen pressure during growth and interfacial coupling. Here we demonstrate that the octahedral rotation of BFO film is changed using tetragonal a0a0c- tilted-SRO bottom electrodes. In this work, BFO/SRO heterostructure is fabricated to SrTiO3 (001) single crystal substrates by pulsed laser deposition at different oxygen partial pressures. The rotation pattern of FeO6 and the structural symmetry are identified from half-integer reflections using high-resolution X-ray diffraction. The effects depending on octahedral tilting of BFO films on the magnetic and ferroelectric properties will be presented.

  15. Polarized neutron reflectivity studies on epitaxial BiFeO3/La0.7Sr0.3MnO3 heterostructure integrated with Si (100

    Directory of Open Access Journals (Sweden)

    S. R. Singamaneni

    2018-05-01

    Full Text Available This work reports polarized neutron reflectivity (PNR measurements performed using the Magnetism Reflectometer at Oak Ridge National Laboratory on epitaxial BiFeO3(BFO/La0.7Sr0.3MnO3(LSMO/SrTiO3(STO/MgO/TiN heterostructure deposited on Si (100 substrates. By measuring the angular dependence of neutrons reflected from the sample, PNR can provide insights on interface magnetic spin structure, chemical composition and magnetic depth profiles with a nanometer resolution. Our first analysis of nuclear scattering length density (NSLD and magnetic scattering length density (MSLD depth profiles measured at 4 K have successfully reproduced most of the expected features of this heterostructure, such as the NSLD for the Si, TiN, MgO, STO, LSMO layers and remanent magnetization (2.28μB/Mn of bulk LSMO. However, the SLD of the BFO is decreased by about 30% from the expected value. When 5 V was applied across the BFO/LSMO interface, we found that the magnetic moment of the LSMO layer could be varied by about 15-20% at 6 K. Several mechanisms such as redistribution of oxygen vacancies, interface strain, charge screening and valence state change at the interface could be at play. Work is in progress to gain an improved in-depth understanding of these effects using MOKE and STEM-Z interface specific measurements.

  16. Polarized neutron reflectivity studies on epitaxial BiFeO3/La0.7Sr0.3MnO3 heterostructure integrated with Si (100)

    Science.gov (United States)

    Singamaneni, S. R.; Prater, J. T.; Glavic, A.; Lauter, V.; Narayan, J.

    2018-05-01

    This work reports polarized neutron reflectivity (PNR) measurements performed using the Magnetism Reflectometer at Oak Ridge National Laboratory on epitaxial BiFeO3(BFO)/La0.7Sr0.3MnO3(LSMO)/SrTiO3(STO)/MgO/TiN heterostructure deposited on Si (100) substrates. By measuring the angular dependence of neutrons reflected from the sample, PNR can provide insights on interface magnetic spin structure, chemical composition and magnetic depth profiles with a nanometer resolution. Our first analysis of nuclear scattering length density (NSLD) and magnetic scattering length density (MSLD) depth profiles measured at 4 K have successfully reproduced most of the expected features of this heterostructure, such as the NSLD for the Si, TiN, MgO, STO, LSMO layers and remanent magnetization (2.28μB/Mn) of bulk LSMO. However, the SLD of the BFO is decreased by about 30% from the expected value. When 5 V was applied across the BFO/LSMO interface, we found that the magnetic moment of the LSMO layer could be varied by about 15-20% at 6 K. Several mechanisms such as redistribution of oxygen vacancies, interface strain, charge screening and valence state change at the interface could be at play. Work is in progress to gain an improved in-depth understanding of these effects using MOKE and STEM-Z interface specific measurements.

  17. Highly textured Sr, Nb co-doped BiFeO3 thin films grown on SrRuO3/Si substrates by rf- sputtering

    International Nuclear Information System (INIS)

    Ostos, C.; Raymond, O.; Siqueiros, J. M.; Suarez-Almodovar, N.; Bueno-Baques, D.; Mestres, L.

    2011-01-01

    In this study, (011)-highly oriented Sr, Nb co-doped BiFeO 3 (BFO) thin films were successfully grown on SrRuO 3 /Si substrates by rf-magnetron sputtering. The presence of parasite magnetic phases was ruled out based on the high resolution x-ray diffraction data. BFO films exhibited a columnar-like grain growth with rms surface roughness values of ≅5.3 nm and average grain sizes of ≅65-70 nm for samples with different thicknesses. Remanent polarization values (2P r ) of 54 μC cm -2 at room temperature were found for the BFO films with a ferroelectric behavior characteristic of an asymmetric device structure. Analysis of the leakage mechanisms for this structure in negative bias suggests Schottky injection and a dominant Poole-Frenkel trap-limited conduction at room temperature. Oxygen vacancies and Fe 3+ /Fe 2+ trap centers are consistent with the surface chemical bonding states analysis from x-ray photoelectron spectroscopy data. The (011)-BFO/SrRuO 3 /Si film structure exhibits a strong magnetic interaction at the interface between the multiferroic film and the substrate layer where an enhanced ferromagnetic response at 5 K was observed. Zero-field cooled (ZFC) and field cooled (FC) magnetization curves of this film system revealed a possible spin glass behavior at spin freezing temperatures below 30 K depending on the BFO film thickness.

  18. Structural, spectroscopic, and dielectric characterizations of Mn-doped 0.67BiFeO3-0.33BaTiO3 multiferroic ceramics

    KAUST Repository

    Hang, Qiming

    2013-09-07

    0.67BiFeO3-0.33BaTiO3 multiferroic ceramics doped with x mol% MnO2 (x = 2–10) were synthesized by solid-state reaction. The formation of a perovskite phase with rhombohedral symmetry was confirmed by X-ray diffraction (XRD). The average grain sizes were reduced from 0.80 μm to 0.50 μm as increasing the Mn-doped levels. Single crystalline nature of the grains was revealed by high-resolution transmission electron microscopy (HRTEM) images and electron diffraction patterns. Polar nano-sized ferroelectric domains with an average size of 9 nm randomly distributed in the ceramic samples were revealed by TEM images. Ferroelectric domain lamellae (71° ferroelectric domains) with an average width of 5 nm were also observed. Vibrational modes were examined by Raman spectra, where only four Raman peaks at 272 cm−1 (E-4 mode), 496 cm−1 (A 1-4 mode), 639 cm−1, and 1338 cm−1 were observed. The blue shifts in the E-4 and A 1-4 Raman mode frequencies were interpreted by a spring oscillator model. The dieletric constants of the present ceramics as a function of the Mn-doped levels exhibited a V-typed curve. They were in the range of 350–700 measured at 103 Hz, and the corresponding dielectric losses were in range of 0.43–0.96, approaching to 0.09 at 106 Hz.

  19. Structural, spectroscopic, and dielectric characterizations of Mn-doped 0.67BiFeO3-0.33BaTiO3 multiferroic ceramics

    KAUST Repository

    Hang, Qiming; Zhou, Wenke; Zhu, Xinhua; Zhu, Jianmin; Liu, Zhiguo; Al-Kassab, Talaat

    2013-01-01

    0.67BiFeO3-0.33BaTiO3 multiferroic ceramics doped with x mol% MnO2 (x = 2–10) were synthesized by solid-state reaction. The formation of a perovskite phase with rhombohedral symmetry was confirmed by X-ray diffraction (XRD). The average grain sizes were reduced from 0.80 μm to 0.50 μm as increasing the Mn-doped levels. Single crystalline nature of the grains was revealed by high-resolution transmission electron microscopy (HRTEM) images and electron diffraction patterns. Polar nano-sized ferroelectric domains with an average size of 9 nm randomly distributed in the ceramic samples were revealed by TEM images. Ferroelectric domain lamellae (71° ferroelectric domains) with an average width of 5 nm were also observed. Vibrational modes were examined by Raman spectra, where only four Raman peaks at 272 cm−1 (E-4 mode), 496 cm−1 (A 1-4 mode), 639 cm−1, and 1338 cm−1 were observed. The blue shifts in the E-4 and A 1-4 Raman mode frequencies were interpreted by a spring oscillator model. The dieletric constants of the present ceramics as a function of the Mn-doped levels exhibited a V-typed curve. They were in the range of 350–700 measured at 103 Hz, and the corresponding dielectric losses were in range of 0.43–0.96, approaching to 0.09 at 106 Hz.

  20. Measure of absorption in multistep compound processes

    International Nuclear Information System (INIS)

    Carlson, B.V.; Hussein, M.S.

    1982-01-01

    The Moldauer-Simonius theorem, that relates the modulus of the determinant of the average, optical, S-matrix, to the average width and spacing of the compound nucleus resonances, is generalized to the multiclass resonances situation encountered in pre-equilibrium reactions. Corrections to the generalized M/S theorem are seen to be connected primarily to the width distribution of the widest doorway class. (Author) [pt

  1. Some functional limit theorems for compound Cox processes

    Energy Technology Data Exchange (ETDEWEB)

    Korolev, Victor Yu. [Faculty of Computational Mathematics and Cybernetics, Moscow State University, Moscow (Russian Federation); Institute of Informatics Problems FRC CSC RAS (Russian Federation); Chertok, A. V. [Faculty of Computational Mathematics and Cybernetics, Moscow State University, Moscow (Russian Federation); Euphoria Group LLC (Russian Federation); Korchagin, A. Yu. [Faculty of Computational Mathematics and Cybernetics, Moscow State University, Moscow (Russian Federation); Kossova, E. V. [Higher School of Economics National Research University, Moscow (Russian Federation); Zeifman, Alexander I. [Vologda State University, S.Orlova, 6, Vologda (Russian Federation); Institute of Informatics Problems FRC CSC RAS, ISEDT RAS (Russian Federation)

    2016-06-08

    An improved version of the functional limit theorem is proved establishing weak convergence of random walks generated by compound doubly stochastic Poisson processes (compound Cox processes) to Lévy processes in the Skorokhod space under more realistic moment conditions. As corollaries, theorems are proved on convergence of random walks with jumps having finite variances to Lévy processes with variance-mean mixed normal distributions, in particular, to stable Lévy processes.

  2. Some functional limit theorems for compound Cox processes

    International Nuclear Information System (INIS)

    Korolev, Victor Yu.; Chertok, A. V.; Korchagin, A. Yu.; Kossova, E. V.; Zeifman, Alexander I.

    2016-01-01

    An improved version of the functional limit theorem is proved establishing weak convergence of random walks generated by compound doubly stochastic Poisson processes (compound Cox processes) to Lévy processes in the Skorokhod space under more realistic moment conditions. As corollaries, theorems are proved on convergence of random walks with jumps having finite variances to Lévy processes with variance-mean mixed normal distributions, in particular, to stable Lévy processes.

  3. Application of Transforms in a Compound Demands Process

    Directory of Open Access Journals (Sweden)

    Ou Tang

    2012-10-01

    Full Text Available The compound distribution is of interest for the study of inventoryproblem, since it provides a more flexible description ofthe stochastic properties of the system compared to many otherapproaches such as renewal processes. However, due to the difficultiesof obtaining analytical results for the compound distribution,such a type of study is usually limited to searching for agood approximation for replacing the complex model. This paperinvestigates the possibility to extend a previous stochastic inventorymodel to cover a compound demand process. Transformmethods again play an imp01tant role in the analysis forcapturing the stochastic prope1ties of the compound distribution.

  4. Approach to Exchange Bias Effect in La2/3Ca1/3MnO3/BiFeO3 and BiFeO3/ La2/3Ca1/3MnO3 Bilayers

    Science.gov (United States)

    Dominguez, Claribel; Ordonez, John; Diez, Sandra; Gomez, Maria; Guénon, Stefan; Schuller, Ivan

    2013-03-01

    We have grown bilayers of ferromagnetic La2/3Ca1/3MnO3 (LCMO) and multiferroic BiFeO3 (BFO) on (100) SrTiO3 (STO) substrates, by DC- and magnetron RF -sputtering technique, respectively, at high-oxygen pressures. We maintain constant the thickness of the layers (tBFO=72nm; tLCMO=80nm). Temperature dependence of the resistivity indicates that the MI-transition temperature of the manganite in the BFO/LCMO/STO is affected by the presence of the BFO layer in comparison with TMI for the single LCMO layer. Furthermore, temperature dependence of magnetization shows that the BFO/LCMO/STO bilayer has higher Curie temperature than that for LCMO/BFO/STO, indicating a strong structural dependence of the LCMO layer with magnetic response. The dependence of the magnetic moment with magnetic field after field cooling gives indication of the existence of Exchange Bias effect in the LCMO/BFO/STO bilayer. Isothermal loops also display dependence of the Exchange Bias magnitude with field cooling. This work has been supported by UNIVALLE Research Project CI 7864, and ``El Patrimonio Autónomo Fondo Nacional de Financiamiento para CT&I FJC,'' Contract RC - No. 275-2011, COLCIENCIAS-CENM, Colombia

  5. their use as Accelerator in Curing Process of Rubber Compounds

    Directory of Open Access Journals (Sweden)

    S. taghvaee

    2007-06-01

    Full Text Available In some special cases, rubber compounds with high amounts of unsaturated elastomer are recommended with organic sulfur donors instead of mineral sulfurs. In this condition, activated sulfur is produced in situ and curingprocess is facilitated without accelerators. Organic sulfur donor compounds have low thermal stability and in the vulcanization temperature produce free and activated sulfurs. The advantages of these compounds are:1. High effectiveness of curing agent in low quantities in rubber compounds manufacturing.2. Producing activated sulfurs in controlled condition and avoiding the over curing of rubber compounds.In this report the novel synthesis of some derivatives of diamino-disulfides which can be applied as sulfur donors in vulcanization of special rubber compounds is introduced. The key process is reaction of sulfurmonochloride with amines in petroleum ether as solvent in low temperature. Dithio-dimorpholine(DTDM, dithio-dipipyridyl (DTDP, dithio-bis dibutylamine (DTBDB and dithio-bisdiisopropyl amine (DTBDI were prepared according to this method. All products thus obtained were characterized by 1H and 13C-NMR spectroscopies. The effects of accelerating and sulfur donoring of all prepared agents were detected in rubber compounds with natural and synthetic rubber bases. All physical, chemical, reological and mechanical properties of rubber compounds based on prepared sulfur donors were characterized.

  6. Containerless automated processing of intermetallic compounds and composites

    Science.gov (United States)

    Johnson, D. R.; Joslin, S. M.; Reviere, R. D.; Oliver, B. F.; Noebe, R. D.

    1993-01-01

    An automated containerless processing system has been developed to directionally solidify high temperature materials, intermetallic compounds, and intermetallic/metallic composites. The system incorporates a wide range of ultra-high purity chemical processing conditions. The utilization of image processing for automated control negates the need for temperature measurements for process control. The list of recent systems that have been processed includes Cr, Mo, Mn, Nb, Ni, Ti, V, and Zr containing aluminides. Possible uses of the system, process control approaches, and properties and structures of recently processed intermetallics are reviewed.

  7. Optical, ferroelectric and magnetic properties of multiferroelectric BiFeO3-(K0.5Na0.5)0.4(Sr 0.6Ba0.4)0.8Nb2O6 thin films

    KAUST Repository

    Yao, Yingbang

    2014-02-01

    Multiferroic BiFeO3-(K0.5Na0.5) 0.4(Sr0.6Ba0.4)0.8Nb 2O6 (BFO-KNSBN) trilayer thin films, were epitaxially grown on MgO(0 0 1) and SrTiO3(0 0 1) by using pulsed laser deposition (PLD). Their ferroelectric, magnetic, dielectric and optical properties were investigated. It was found that both ferroelectric polarization and dielectric constant of the films were enhanced by introducing KNSBN as a barrier layer. Meanwhile, ferromagnetism of BFO was maintained. More interestingly, a double hysteresis magnetic loop was observed in the KNSBN-BFO-KNSBN trilayer films, where exchange bias and secondary phase in the BFO layer played crucial roles. Interactions between adjacent layers were revealed by temperature-dependent Raman spectroscopic measurements. © 2013 Elsevier B.V. All rights reserved.

  8. Electrical and piezoelectric properties of BiFeO3 thin films grown on SrxCa1−xRuO3-buffered SrTiO3 substrates

    KAUST Repository

    Yao, Yingbang

    2012-06-01

    (001)-oriented BiFeO 3 (BFO) thin films were grown on Sr xCa 1-xRuO 3- (SCRO; x = 1, 0.67, 0.33, 0) buffered SrTiO 3 (001) substrates using pulsed laser deposition. The microstructural, electrical, ferroelectric, and piezoelectric properties of the thin films were considerably affected by the buffer layers. The interface between the BFO films and the SCRO-buffer layer was found to play a dominant role in determining the electrical and piezoelectric behaviors of the films. We found that films grown on SrRuO 3-buffer layers exhibited minimal electrical leakage while films grown on Sr 0.33Ca 0.67RuO 3-buffer layers had the largest piezoelectric response. The origin of this difference is discussed. © 2012 American Institute of Physics.

  9. Experience with compound words influences their processing: An eye movement investigation with English compound words.

    Science.gov (United States)

    Juhasz, Barbara J

    2016-11-14

    Recording eye movements provides information on the time-course of word recognition during reading. Juhasz and Rayner [Juhasz, B. J., & Rayner, K. (2003). Investigating the effects of a set of intercorrelated variables on eye fixation durations in reading. Journal of Experimental Psychology: Learning, Memory and Cognition, 29, 1312-1318] examined the impact of five word recognition variables, including familiarity and age-of-acquisition (AoA), on fixation durations. All variables impacted fixation durations, but the time-course differed. However, the study focused on relatively short, morphologically simple words. Eye movements are also informative for examining the processing of morphologically complex words such as compound words. The present study further examined the time-course of lexical and semantic variables during morphological processing. A total of 120 English compound words that varied in familiarity, AoA, semantic transparency, lexeme meaning dominance, sensory experience rating (SER), and imageability were selected. The impact of these variables on fixation durations was examined when length, word frequency, and lexeme frequencies were controlled in a regression model. The most robust effects were found for familiarity and AoA, indicating that a reader's experience with compound words significantly impacts compound recognition. These results provide insight into semantic processing of morphologically complex words during reading.

  10. Nonparametric Bayesian inference for multidimensional compound Poisson processes

    NARCIS (Netherlands)

    Gugushvili, S.; van der Meulen, F.; Spreij, P.

    2015-01-01

    Given a sample from a discretely observed multidimensional compound Poisson process, we study the problem of nonparametric estimation of its jump size density r0 and intensity λ0. We take a nonparametric Bayesian approach to the problem and determine posterior contraction rates in this context,

  11. Handbook of compound semiconductors growth, processing, characterization, and devices

    CERN Document Server

    Holloway, Paul H

    1996-01-01

    This book reviews the recent advances and current technologies used to produce microelectronic and optoelectronic devices from compound semiconductors. It provides a complete overview of the technologies necessary to grow bulk single-crystal substrates, grow hetero-or homoepitaxial films, and process advanced devices such as HBT's, QW diode lasers, etc.

  12. Development of the multistep compound process calculation code

    Energy Technology Data Exchange (ETDEWEB)

    Kawano, Toshihiko [Kyushu Univ., Fukuoka (Japan)

    1998-03-01

    A program `cmc` has been developed to calculate the multistep compound (MSC) process by Feshback-Kerman-Koonin. A radial overlap integral in the transition matrix element is calculated microscopically, and comparisons are made for neutron induced {sup 93}Nb reactions. Strengths of the two-body interaction V{sub 0} are estimated from the total MSC cross sections. (author)

  13. [Exposure to metal compounds in occupational galvanic processes].

    Science.gov (United States)

    Surgiewicz, Jolanta; Domański, Wojciech

    2006-01-01

    Occupational galvanic processes are provided in more than 600 small and medium enterprises in Poland. Workers who deal with galvanic coating are exposed to heavy metal compounds: tin, silver, copper and zinc. Some of them are carcinogenic, for example, hexavalent chromium compounds, nickel and cadmium compounds. Research covered several tens of workstations involved in chrome, nickel, zinc, tin, silver, copper and cadmium plating. Compounds of metals present in the air were determined: Cr, Ni, Cd, Sn, Ag--by atomic absorption spectrometry with electrothermal atomization (ET-AAS) and Zn--by atomic absorption spectrometry with flame atomization (F-AAS). The biggest metal concentrations--of silver and copper--were found at workstations of copper, brass, cadmium, nickel and chrome plating, conducted at the same time. Significant concentrations of copper were found at workstations of maintenance bathing and neutralizing of sewage. The concentrations of metals did not exceed Polish MAC values. MAC values were not exceeded for carcinogenic chromium(VI), nickel or cadmium, either. In galvanic processes there was no hazard related to single metals or their compounds, even carcinogenic ones. Combined exposure indicators for metals at each workstation did not exceed 1, either. However, if there are even small quantities of carcinogenic agents, health results should always be taken into consideration.

  14. Development of volatile compounds in processed cheese during storage

    DEFF Research Database (Denmark)

    Sunesen, Lars Oddershede; Lund, Pia; Sørensen, J.

    2002-01-01

    The purpose of this work teas to study tire impact of storage conditions, such as light and temperature, on the development of volatile compounds to processed cheese. Cheese in glass containers was stored at 5, 20 or 37 degreesC in light or darkness for up to 1 yr. Dynamic headspace and gas...... chromatography/mass spectrometry leas used for quantifying 28 volatile organic compounds at eight stages during tree storage period. Through principal component analysis, three important storage parameters could be identified. Principal components 1, 2 and 3 reflected storage tinge, conditions of light...

  15. Treating contaminated organic compounds using the DETOX process

    International Nuclear Information System (INIS)

    Elsberry, K.; Dhooge, P.M.

    1993-01-01

    Waste matrices containing organic compounds, radionuclides, and metals pose difficult problems in waste treatment and disposal when the organic compounds and/or metals are considered to be hazardous. This paper describes the results of bench-scale studies of DETOX applied to the components of liquid mixed wastes, with the goal of establishing parameters for designing a prototype waste treatment unit. Apparent reaction rate orders for organic compounds and the dependence of apparent reaction rate on solution composition and the contact area were measured for vacuum pump oil, scintillation fluids, and trichloroethylene. Reaction rate was superior in chloride-based solutions and was proportional to the contact area above about 20 g/kg loading of organic material. Oxidations in 4-L volume, mixed bench-top reactor have given destruction efficiencies of 0.999999+ g/g for common organic compounds. Reaction rates achieved in the mixed bench-top reactor were one to two orders of magnitude greater than had been achieved in unmixed reactions; a thoroughly mixed reactor should be capable of oxidizing 10 to 100+ g of organic material per L-hr. Results are also presented on the solvation efficiency of DETOX for mercury, cerium, and neodymium, and for removal/destruction of organic compounds sorbed on vermiculite. The next stage of development will be converting the bench-top unit to continuous processing

  16. INFLUENCE OF INORGANIC COMPOUNDS ON THE PROCESS OF PHOTOCATALYSIS OF BIOLOGICALLY ACTIVE COMPOUNDS

    Directory of Open Access Journals (Sweden)

    Edyta Kudlek

    2017-07-01

    Full Text Available Constant increase in concentration of organic micropollutants in the water environment influences the development of methods for their effective elimination from various matrices released into aquatic ecosystems. One of widely described in literature processes for the decomposition of hardly-biodegradable pollutants is the process of heterogeneous photocatalysis. The paper presents the influence of inorganic substances on the decomposition of polycyclic aromatic hydrocarbons (anthracene and benzo[a]pyrene, industrial admixtures - octylphenol and pharmaceutical compounds - diclofenac in the photocatalysis process conducted in the presence of TiO2. It has been shown that the presence of Cl- ions did not affect the photochemical reaction of the micropollutant decomposition. Whereas, the presence of CO3(2-, SO4(2- and HPO4(2- ions inhibited the decolonization of octylphenol and diclofenac, while the degradation efficiency of anthracene and benzo[a]pyrene was reduced only by the presence of CO3(2- and HCO3- anions. The photooxidation of micropollutants in solutions containing Al(3+ oraz Fe(3+ cations proceeded with a much lower efficiency than that for solution without inorganic compounds. The analysis of the kinetics of the photocatalytic decomposition of selected micropollutants show a decrease in the reaction rate constant and an increase in their half-life due to the blocking of theactive semiconductor centers by inorganic compounds. In addition,the toxicological analysis inducated the generation of micropollutant oxidation by-products, which aggravate the quality of treated aqueous solutions.

  17. Statistical features of pre-compound processes in nuclear reactions

    International Nuclear Information System (INIS)

    Hussein, M.S.; Rego, R.A.

    1983-04-01

    Several statistical aspects of multistep compound processes are discussed. The connection between the cross-section auto-correlation function and the average number of maxima is emphasized. The restrictions imposed by the non-zero value of the energy step used in measuring the excitation fuction and the experimental error are discussed. Applications are made to the system 25 Mg( 3 He,p) 27 Al. (Author) [pt

  18. Process for removing heavy metal compounds from heavy crude oil

    Science.gov (United States)

    Cha, Chang Y.; Boysen, John E.; Branthaver, Jan F.

    1991-01-01

    A process is provided for removing heavy metal compounds from heavy crude oil by mixing the heavy crude oil with tar sand; preheating the mixture to a temperature of about 650.degree. F.; heating said mixture to up to 800.degree. F.; and separating tar sand from the light oils formed during said heating. The heavy metals removed from the heavy oils can be recovered from the spent sand for other uses.

  19. Governing processes for reactive nitrogen compounds in the European atmosphere

    DEFF Research Database (Denmark)

    Hertel, Ole; Skjøth, Carsten Ambelas; Reis, S.

    2012-01-01

    +)), oxidized nitrogen (NOy: nitrogen monoxide (NO) + nitrogen dioxide (NO2) and their reaction products) as well as organic nitrogen compounds (organic N). Pollution abatement strategies need to take into account the differences in the governing processes of these compounds when assessing their impact...... on ecosystem services, biodiversity, human health and climate. NOx (NO+NO2) emitted from traffic affects human health in urban areas where the presence of buildings increases the residence time in streets. In urban areas this leads to enhanced exposure of the population to NOx concentrations. NOx emissions.......5 and PM10 (mass of aerosols with an aerodynamic diameter of less than 2.5 and 10 mu m, respectively) with an impact on radiation balance as well as potentially on human health. Little is known quantitatively and qualitatively about organic N in the atmosphere, other than that it contributes a significant...

  20. Governing processes for reactive nitrogen compounds in the European atmosphere

    Directory of Open Access Journals (Sweden)

    O. Hertel

    2012-12-01

    Full Text Available Reactive nitrogen (Nr compounds have different fates in the atmosphere due to differences in the governing processes of physical transport, deposition and chemical transformation. Nr compounds addressed here include reduced nitrogen (NHx: ammonia (NH3 and its reaction product ammonium (NH4+, oxidized nitrogen (NOy: nitrogen monoxide (NO + nitrogen dioxide (NO2 and their reaction products as well as organic nitrogen compounds (organic N. Pollution abatement strategies need to take into account the differences in the governing processes of these compounds when assessing their impact on ecosystem services, biodiversity, human health and climate. NOx (NO + NO2 emitted from traffic affects human health in urban areas where the presence of buildings increases the residence time in streets. In urban areas this leads to enhanced exposure of the population to NOx concentrations. NOx emissions generally have little impact on nearby ecosystems because of the small dry deposition rates of NOx. These compounds need to be converted into nitric acid (HNO3 before removal through deposition is efficient. HNO3 sticks quickly to any surface and is thereby either dry deposited or incorporated into aerosols as nitrate (NO3. In contrast to NOx compounds, NH3 has potentially high impacts on ecosystems near the main agricultural sources of NH3 because of its large ground-level concentrations along with large dry deposition rates. Aerosol phase NH4+ and NO3 contribute significantly to background PM2.5 and PM10 (mass of aerosols with an aerodynamic diameter of less than 2.5 and 10 μm, respectively with an impact on radiation balance as well as potentially on human

  1. Optimization of Processing Technology of Compound Dandelion Wine

    Directory of Open Access Journals (Sweden)

    Wu Jixuan

    2016-01-01

    Full Text Available Exploring dandelion food has been the concern in fields of the food processing and pharmaceutical industry for playing exact curative effect on high-fat-diet induced hepatic steatosis and diuretic activity. Few dandelion foods including drinks and microencapsulation were explored and unilateral dandelion wine were less carried out for its bitter flavour. In tis paper, to optimize the processing technologies of fermented compound wine from dandelion root, the orthogonal experiment design method was used to composite dandelion root powder with glutinous rice and schisandra fruit and optimize the fermenting parameters. Four factors with dandelion content, schisandra content, acidity and sugar content were discussed. The acidity factor was firstly confirmed as 7.0 g/L. The other three factors were confirmed by a series experiments as dandelion 0.55%, schisandra 0.5%, sugar 22%. With nine step processing of mixing substrate, stirring with water, cooking rice, amylase saccharification, pectinase hydrolysis, adjusting juice, fermenting with yeast, fitering, aging, sterilization, a light yellow wine with the special taste with flavour of dandelion, schisandra and rice and less bitter, few index were determined as 14.7% alcohol, 6.85 g/L acidity. A dandelion fermented compound wine with suitable flavour and sanitarian function was developed for enriching the dandelion food.

  2. Processamento e caracterizações estruturais, microestruturais e ferroelétricas do composto magnetoelétrico BiFeO3-PbTiO3 obtido pelo método de Pechini

    Directory of Open Access Journals (Sweden)

    V. F. Freitas

    Full Text Available Resumo Neste trabalho uma rota alternativa de síntese, o método de Pechini modificado, foi utilizada para obter nanopartículas do composto BiFeO3-PbTiO3 (BFPT. As imagens obtidas por microscopia eletrônica de varredura revelaram tamanhos de partículas inferiores a 120 nm. Análises estruturais apontaram a organização estrutural do composto (formação de estruturas com simetria tetragonal como função da temperatura de síntese. Cálculos da polarização espontânea indicaram a intensidade alcançada no composto BFPT. As análises de densidade eletrônica obtidas pelo método da máxima entropia indicaram a configuração das ligações químicas presentes no composto.

  3. Experimental and first principles investigation of the multiferroics BiFeO3 and Bi0.9Ca0.1FeO3: Structure, electronic, optical and magnetic properties

    International Nuclear Information System (INIS)

    Gao, Ning; Quan, Chuye; Ma, Yuhui; Han, Yumin; Wu, Zhenli; Mao, Weiwei

    2016-01-01

    We propose first-principles methods to study the structure, electronic, optical and magnetic properties of BiFeO 3 (BFO) and Bi 0.9 Ca 0.1 FeO 3 (BCFO). The morphology, optical band gap as well as magnetic hysteresis also have been investigated using experimental methods. X-ray diffraction data shows that Bi-site doping with Ca could result in a transition of crystal structure (from single phase rhombohedral (R3c) to two phase coexistence). Changing of Fermi level and decreasing of band gap indicating that the Ca-doped BFO exhibit a typical half-metallic nature. The optical absorption properties are related to the electronic structure and play the key role in determining their band gaps, also we have analyzed the inter-band contribution to the theory of optical properties such as absorption spectra, dielectric constant, energy-loss spectrum, absorption coefficient, optical reflectivity, and refractive index of BCFO. Enhancement of magnetic properties after doping is proved by both experimental and calculated result, which can be explained by size effect and structural distortion.

  4. Quick and enhanced degradation of bisphenol A by activation of potassium peroxymonosulfate to SO4rad - with Mn-doped BiFeO3 nanoparticles as a heterogeneous Fenton-like catalyst

    Science.gov (United States)

    Soltani, Tayyebeh; Tayyebi, Ahmad; Lee, Byeong-Kyu

    2018-05-01

    Mn-doped BiFeO3 magnetic nanoparticles (BFO MNPs), namely BiFe1-xMnxO3 (x = 0.05 and 0.10), were successfully synthesized using a simple and novel sol-gel method and then applied as a highly efficient peroxymonosulfate (KHSO5, PMS) activation catalyst for the fast degradation of bisphenol A (BPA) from aqueous solution. The strong PMS activation ability of 10% Mn-doped BFO MNPs without any metal leaching due to the simultaneous effects of iron and manganese ions in the production of radical sulfate (SO4rad -), caused complete BPA degradation in 15 min, which was much faster than that using combinations with H2O2. TOC was reduced to 33%, 23% and 13% by PMS activated with BFO, 5 and 10% Mn doped BFO, respectively, which are 2.1, 2.6 and 3.15-fold lower than that same nanoparticles activated with H2O2. The photocatalytic mechanism of BPA with the simultaneous effects of iron and manganese ions in Mn-doped BFO was explored. The addition of KBrO3 and NaNO3 salts into Mn-doped BFO/PMS system reduced the complete BPA degradation time to 10 min, whereas Na2CO3 and NaCl salt addition retarded it, because salt addition can generate radical species that are either more or less active than SO4rad -.

  5. A general theory for radioactive processes in rare earth compounds

    International Nuclear Information System (INIS)

    Acevedo, R.; Meruane, T.

    1998-01-01

    The formal theory of radiative processes in centrosymmetric coordination compounds of the Ln X 3+ is a trivalent lanthanide ion and X -1 =Cl -1 , Br -1 ) is put forward based on a symmetry vibronic crystal field-ligand polarisation model. This research considers a truncated basis set for the intermediate states of the central metal ion and have derived general master equations to account for both the overall observed spectral intensities and the measured relative vibronic intensity distributions for parity forbidden but vibronically allowed electronic transitions. In addition, a procedure which includes the closure approximation over the intermediate electronic states is included in order to estimate quantitative crystal field contribution to the total transition dipole moments of various and selected electronic transitions. This formalism is both general and flexible and it may be employed in any electronic excitations involving f N type configurations for the rare earths in centrosymmetric co-ordination compounds in cubic environments and also in doped host crystals belonging to the space group Fm 3m. (author)

  6. Process for removal of sulfur compounds from fuel gases

    Science.gov (United States)

    Moore, Raymond H.; Stegen, Gary E.

    1978-01-01

    Fuel gases such as those produced in the gasification of coal are stripped of sulfur compounds and particulate matter by contact with molten metal salt. The fuel gas and salt are intimately mixed by passage through a venturi or other constriction in which the fuel gas entrains the molten salt as dispersed droplets to a gas-liquid separator. The separated molten salt is divided into a major and a minor flow portion with the minor flow portion passing on to a regenerator in which it is contacted with steam and carbon dioxide as strip gas to remove sulfur compounds. The strip gas is further processed to recover sulfur. The depleted, minor flow portion of salt is passed again into contact with the fuel gas for further sulfur removal from the gas. The sulfur depleted, fuel gas then flows through a solid absorbent for removal of salt droplets. The minor flow portion of the molten salt is then recombined with the major flow portion for feed to the venturi.

  7. Surface passivation process of compound semiconductor material using UV photosulfidation

    Science.gov (United States)

    Ashby, Carol I. H.

    1995-01-01

    A method for passivating compound semiconductor surfaces by photolytically disrupting molecular sulfur vapor with ultraviolet radiation to form reactive sulfur which then reacts with and passivates the surface of compound semiconductors.

  8. Antimicrobial compounds as side products from the agricultural processing industry

    NARCIS (Netherlands)

    Sumthong, Pattarawadee

    2007-01-01

    Antimicrobial compounds have many applications, in medicines, food, agriculture, livestock, textiles, paints, and wood protectants. Microorganisms resistant to most antibiotics are rapidly spreading. Consequently there is an urgent and continuous need for novel antimicrobial compounds. Most

  9. Lindley frailty model for a class of compound Poisson processes

    Science.gov (United States)

    Kadilar, Gamze Özel; Ata, Nihal

    2013-10-01

    The Lindley distribution gain importance in survival analysis for the similarity of exponential distribution and allowance for the different shapes of hazard function. Frailty models provide an alternative to proportional hazards model where misspecified or omitted covariates are described by an unobservable random variable. Despite of the distribution of the frailty is generally assumed to be continuous, it is appropriate to consider discrete frailty distributions In some circumstances. In this paper, frailty models with discrete compound Poisson process for the Lindley distributed failure time are introduced. Survival functions are derived and maximum likelihood estimation procedures for the parameters are studied. Then, the fit of the models to the earthquake data set of Turkey are examined.

  10. Half-metallicity in a BiFeO3/La2/3Sr1/3MnO3 superlattice: A first-principles study

    KAUST Repository

    Jiwuer, Jilili

    2013-06-01

    We present first-principles results for the electronic, magnetic, and optical properties of the heterostructure as obtained by spin-polarized calculations using density functional theory. The electronic states of the heterostructure are compared to those of the bulk compounds. Structural relaxation turns out to have only a minor impact on the chemical bonding, even though the oxygen octahedra in develop some distortions due to the interface strain. While a small charge transfer affects the heterointerfaces, our results demonstrate that the half-metallic character of is fully maintained. © EPLA, 2013.

  11. Processing of volatile organic compounds by microwave plasmas

    International Nuclear Information System (INIS)

    Mizeraczyk, J.; Jasinski, M.; Dors, M.; Zakrzewski, Z.

    2011-01-01

    In this paper atmospheric pressure microwave discharge methods and devices used for producing the nonthermal plasmas for processing of gases are presented. The main part of the paper concerns the microwave plasma sources (MPSs) for environmental protection applications. A few types of the MPSs, i.e. waveguidebased surface wave sustained MPS, coaxial-line-based and waveguide-based nozzle-type MPSs, waveguidebased nozzleless cylinder-type MPS and MPS for microdischarges are presented. Also, results of the laboratory experiments on the plasma processing of several highly-concentrated (up to several tens percent) volatile organic compounds (VOCs), including Freon-type refrigerants, in the moderate (200-400 W) waveguide-based nozzletype MPS (2.45 GHz) are presented. The results showed that the microwave discharge plasma fully decomposed the VOCs at relatively low energy cost. The energy efficiency of VOCs decomposition reached 1000 g/kWh. This suggests that the microwave discharge plasma can be a useful tool for environmental protection applications. In this paper also results of the use of the waveguide-based nozzleless cylinder-type MPS to methane reforming into hydrogen are presented. (author)

  12. Processing of volatile organic compounds by microwave plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Mizeraczyk, J. [Centre for Plasma and Laser Engineering, Szewalski Institute of Fluid-Flow Machinery, Polish Academy of Sciences, Gdansk (Poland); Department of Marine Electronics, Gdynia Martime University, Gdynia (Poland); Jasinski, M.; Dors, M.; Zakrzewski, Z. [Centre for Plasma and Laser Engineering, Szewalski Institute of Fluid-Flow Machinery, Polish Academy of Sciences, Gdansk (Poland)

    2011-07-01

    In this paper atmospheric pressure microwave discharge methods and devices used for producing the nonthermal plasmas for processing of gases are presented. The main part of the paper concerns the microwave plasma sources (MPSs) for environmental protection applications. A few types of the MPSs, i.e. waveguidebased surface wave sustained MPS, coaxial-line-based and waveguide-based nozzle-type MPSs, waveguidebased nozzleless cylinder-type MPS and MPS for microdischarges are presented. Also, results of the laboratory experiments on the plasma processing of several highly-concentrated (up to several tens percent) volatile organic compounds (VOCs), including Freon-type refrigerants, in the moderate (200-400 W) waveguide-based nozzletype MPS (2.45 GHz) are presented. The results showed that the microwave discharge plasma fully decomposed the VOCs at relatively low energy cost. The energy efficiency of VOCs decomposition reached 1000 g/kWh. This suggests that the microwave discharge plasma can be a useful tool for environmental protection applications. In this paper also results of the use of the waveguide-based nozzleless cylinder-type MPS to methane reforming into hydrogen are presented. (author)

  13. Microstructure, Piezoelectric, and Ferroelectric Properties of BZT-Modified BiFeO3-BaTiO3 Multiferroic Ceramics with MnO2 and CuO Addition

    Science.gov (United States)

    Guan, Shibo; Yang, Huabin; Chen, Guangcong; Zhang, Rui

    2018-02-01

    A new lead-free piezoelectric ceramic, 0.67BiFeO3-0.33BaTiO3-xBi(Zn0.5Ti0.5) O3 + 0.0035MnO2 + 0.004CuO, was prepared through the solid-state reaction route. The ceramic was sintered in the 950-990°C range. In this paper, the crystal structure of the sample is pure perovskite structure with a pseudo-cubic structure in the range of x = 0-0.05, and does not change greatly with the increase of x. The grain size increases first and then decreases with the increase of x. The addition of Bi(Zn0.5Ti0.5) O3(BZT) promoted the grain growth of the sample. The piezoelectric constant reached the maximum value of d 33 = 188 pC/N, electromechanical coupling coefficient k p = 0.301 and the remanent polarization P r = 61.20 μC/cm2 at x = 0.03. It has a high Curie temperature of T c = 420°C. On the other hand, the depolarization temperature reaches the maximum value, T d = 426°C, at x = 0. A small amount of BZT doping can improve the piezoelectric, dielectric, and ferroelectric properties of the samples. Therefore, this material can be considered as a promising lead-free piezoelectric ceramic material in the application field of high-temperature materials.

  14. Residual tensile stresses and piezoelectric properties in BiFeO3-Bi(Zn1/2Ti1/2O3-PbTiO3 ternary solid solution perovskite ceramics

    Directory of Open Access Journals (Sweden)

    Weilin Zheng

    2016-08-01

    Full Text Available For low dielectric loss perovskite-structured (1-x-yBiFeO3-xBi(Zn1/2Ti1/2O3-yPbTiO3 (BF-BZT-PT (x = 0.04-0.15 and y = 0.15-0.26 ceramics in rhombohedral/tetragonal coexistent phase, structural phase transitions were studied using differential thermal analyzer combined with temperature-dependent dielectric measurement. Two lattice structural phase transitions are disclosed in various BF-BZT-PT perovskites, which is different from its membership of BiFeO3 exhibiting just one lattice structural phase transition at Curie temperature TC= 830oC. Consequently, residual internal tensile stresses were revealed experimentally through XRD measurements on ceramic pellets and counterpart powders, which are reasonably attributed to special structural phase transition sequence of BF-BZT-PT solid solution perovskites. Low piezoresponse was observed and argued extrinsically resulting from residual tensile stresses pinning ferroelectric polarization switching. Post-annealing and subsequent quenching was found effective for eliminating residual internal stresses in those BZT-less ceramics, and good piezoelectric property of d33 ≥ 28 pC/N obtained for 0.70BF-0.08BZT-0.22PT and 0.05 wt% MnO2-doped 0.70BF-0.04BZT-0.26PT ceramics with TC ≥ 640oC, while it seemed no effective for those BZT-rich BF-BZT-PT ceramics with x = 0.14 and 0.15 studied here.

  15. Immunomodulatory Effects of Soybeans and Processed Soy Food Compounds.

    Science.gov (United States)

    Tezuka, Hiroyuki; Imai, Shinjiro

    2015-01-01

    Inflammation is an immune response against both internal and external antigens in organisms, particularly in mammals, and includes both uncontrolled chronic and low-grade inflammations. Uncontrolled chronic inflammation often leads to severe diseases such as vascular disease, arthritis, cancer, diabete, allergy, and autoimmunity. On the other hand, low-grade inflammation is recognized as a relationship between obesity and risk of metabolic syndrome. Elevated production of pro-inflammatory cytokines and mediators is commonly observed in patients with uncontrolled or low-grade inflammation-associated diseases. Plants have been generated phytochemicals to overcome inflammations and infections through evolution. Phytochemicals belong to alkaloids, polyphenols, flavonoids, coumarins, and terpenoids. The consumption of soybeans plays a role in immune modulation through their components such as isoflavones, saponins, and anthocyanins. Recently, it was reported that the application of phytochemicals into patients with inflammatory diseases improves their symptoms. Therefore, it is important to identify novel phytochemicals with immunomodulatory activities. This review introduces and discusses recent advances and patents regarding soybean or processed soy food compounds which exhibit immunomodulatory activity in immune diseases, particularly allergy, by mediating the suppression of inflammatory pathways.

  16. Processing and Properties of PCL/Cotton Linter Compounds

    OpenAIRE

    Bezerra,Elieber Barros; França,Danyelle Campos; Morais,Dayanne Diniz de Souza; Rosa,Morsyleide de Freitas; Morais,João Paulo Saraiva; Araújo,Edcleide Maria; Wellen,Renate Maria Ramos

    2017-01-01

    Biodegradable compounds of poly(ε-caprolactone) (PCL)/ cotton linter were melting mixed with filling content ranging from 1% to 5% w/w. Cotton linter is an important byproduct of textile industry; in this work it was used in raw state and after acid hydrolysis. According to the results of torque rheometry no decaying of viscosity took place during compounding, evidencing absence of breaking down in molecular weight. The thermal stability increased by 20% as observed in HDT for PCL/cotton...

  17. Processing and properties of PCL/cotton linter compounds

    Energy Technology Data Exchange (ETDEWEB)

    Bezerra, Elieber Barros; Franca, Danyelle Campos; Morais, Dayanne Diniz de Souza; Araujo, Edcleide Maria [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Departamento de Engenharia de Materiais; Rosa, Morsyleide de Freitas; Morais, Joao Paulo Saraiva [Embrapa Tropical Agroindustia, Fortaleza, CE (Brazil); Wellen, Renate Maria Ramos, E-mail: wellen.renate@gmail.com [Universidade Federal da Paraiaba (UFPB), Joao Pessoa, PB (Brazil)

    2017-03-15

    Biodegradable compounds of poly(ε-caprolactone) (PCL)/ cotton linter were melting mixed with filling content ranging from 1% to 5% w/w. Cotton linter is an important byproduct of textile industry; in this work it was used in raw state and after acid hydrolysis. According to the results of torque rheometry no decaying of viscosity took place during compounding, evidencing absence of breaking down in molecular weight. The thermal stability increased by 20% as observed in HDT for PCL/cotton nanolinter compounds. Adding cotton linter to PCL did not change its crystalline character as showed by XRD; however an increase in degree of crystallinity was observed by means of DSC. From mechanical tests in tension was observed an increase in ductility of PCL, and from mechanical tests in flexion an increase in elastic modulus upon addition of cotton linter, whereas impact strength presented lower values for PCL/cotton linter and PCL/cotton nanolinter compounds. SEM images showed that PCL presents plastic fracture and cotton linter has an interlacing fibril structure with high L/D ratio, which are in agreement with matrix/fibril morphology observed for PCL/cotton linter compounds. PCL/cotton linter compounds made in this work cost less than neat PCL matrix and presented improved properties making feasible its commercial use. (author)

  18. Aqueous processing of organic compounds in carbonaceous asteroids

    Science.gov (United States)

    Trigo-Rodríguez, Josep Maria; Rimola, Albert; Martins, Zita

    2015-04-01

    There is growing evidence pointing towards a prebiotic synthesis of complex organic species in water-rich undifferentiated bodies. For instance, clays have been found to be associated with complex organic compounds (Pearson et al. 2002; Garvie & Buseck 2007; Arteaga et al. 2010), whereas theoretical calculations have studied the interaction between the organic species and surface minerals (Rimola et al., 2013) as well as surface-induced reactions (Rimola at al. 2007). Now, we are using more detailed analytical techniques to study the possible processing of organic molecules associated with the mild aqueous alteration in CR, CM and CI chondrites. To learn more about these processes we are studying carbonaceous chondrites at Ultra High-Resolution Transmission Electron Microscopy (UHR-TEM). We are particularly interested in the relationship between organics and clay minerals in carbonaceous chondrites (CCs) matrixes (Trigo-Rodríguez et al. 2014, 2015).We want to address two goals: i) identifying the chemical steps in which the organic molecules could have increased their complexity (i.e., surface interaction and catalysis); and ii) studying if the organic matter present in CCs experienced significant processing concomitant to the formation of clays and other minerals at the time in which these planetary bodies experienced aqueous alteration. Here, these two points are preliminarily explored combing experimental results with theoretical calculations based on accurate quantum mechanical methods. References Arteaga O, Canillas A, Crusats J, El-Hachemi Z, Jellison GE, Llorca J, Ribó JM (2010) Chiral biases in solids by effect of shear gradients: a speculation on the deterministic origin of biological homochirality. Orig Life Evol Biosph 40:27-40. Garvie LAJ, Buseck PR (2007) Prebiotic carbon in clays from Orgueil and Ivuna (CI) and Tagish lake (C2 ungrouped) meteorites. Meteorit Planet Sci 42:2111-2117. Pearson VK, Sephton MA, Kearsley AT, Bland AP, Franchi IA, Gilmour

  19. Process for the production of 14C-labelled compounds

    International Nuclear Information System (INIS)

    Oldham, K.G.; Carr, N.G.

    1978-01-01

    The patent describes the production of 14 C-labelled compounds from solution with the aid of algae. A microorganism of the Anacystic species is used, preferably Anacystis nidulans which is also known as 'Indiana 625'. The experiments and their results are described in detail. (UWI) [de

  20. Rare earth intermetallic compounds produced by a reduction-diffusion process

    International Nuclear Information System (INIS)

    Cech, R.E.

    1975-01-01

    A reduction-diffusion process is given for producing novel rare earth intermetallic compounds, such as cobalt--rare earth intermetallic compounds, especially compounds useful in preparing permanent magnets. A particulate mixture of rare earth metal halide, cobalt and calcium hydride is heated to effect reduction of the rare earth metal halide and to diffuse the resulting rare earth metal into the cobalt to form the intermetallic compound

  1. Bioactive compounds in edible flowers processed by radiation

    International Nuclear Information System (INIS)

    Koike, Amanda Cristina Ramos

    2015-01-01

    Edible flowers are increasingly being used in culinary preparations, being also recognized for their potential valuable effects in human health, which require new approaches to improve their conservation and safety. These highly perishable products should be grown without using any pesticide. Irradiation treatment might be the answer to these problems, ensuring food quality, increasing shelf-life and disinfestation of foods. Irradiation treatment might be the answer to these problems, to ensure food quality, to increase shelf-life and disinfestation of foods. Tropaeolum majus L. (nasturtium) and Viola tricolor L. (johnny-jump-up) flowers are widely used in culinary preparations, being also acknowledged for their antioxidant properties and high content of phenolics. The purpose of this study was to evaluate the dose-dependent effects of gamma and electron beam irradiation (doses of 0, 0.5, 0.8 and 1 kGy) on the antioxidant activity, phenolic compounds, physical aspects and antiproliferative potential of edible flowers. Kaempferol-O-hexoside-O-hexoside was the most abundant compound in all samples of Tropaeolum majus flower while pelargonidin-3-O-sophoroside was the major anthocyanin. In general, irradiated samples gave higher antioxidant activity, probably due to their higher amounts of phenolic compounds, which were also favored by the 1.0 kGy dose, regardless of the source . The Viola tricolor samples displayed flavonols as the most abundant phenolic compounds, particularly those derived from quercetin. In general, gamma-irradiated samples, independently of the applied dose, showed higher amounts in phenolic compounds, which were also favored by the 1.0 kGy dose, regardless of the source. The antioxidant activity was also higher among irradiated samples. The two species of edible flowers have not provided the samples did not show potential antiproliferative and cytotoxicity. Accordingly, the applied irradiation treatments seemed to represent a feasible technology

  2. The nested-doorway model of multistep compound processes

    International Nuclear Information System (INIS)

    Hussein, M.S.

    1982-05-01

    The multistep compound contribution to preequilibrium reaction are discussed within the nested-doorway model. Emphasis is placed on the generalized cross-section auto-correlation function. Several of the more widely used concepts in the conventional, one-class, statistical analysis are discussed and generalized to the multiclass case. A summary of the formal results of the nested-doorway model, obtained within Feshbach's projection operator theory is given. (Author) [pt

  3. Degradation of phenolic compounds by using advanced oxidation processes

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, M. [Univ. de los Andes, Escuela Basica de Ingenieria, La Hechicera, Merida (Venezuela); Hincapie, M. [Dept. de Ingenieria Sanitaria y Ambiental, Univ. de Antioquia, Medellin (Colombia); Curco, D.; Contreras, S.; Gimenez, J.; Esplugas, S. [Dept. de Ingenieria Quimica, Facultad de Quimica, Univ. de Barcelona, Barcelona (Spain)

    2003-07-01

    A new empirical kinetic equation [r = k{sub 1}c - k{sub 2} (c{sub 0} - c)] is proposed for the photocatalytic degradation of phenolic compounds. This equation considers the influence of the intermediates in the degradation of the pollutant. The correct formulation of the contaminant mass balance in the experimental device that operates in recycle mode was done. The proposed empirical kinetic equation fitted quite well with the experimental results obtained in the TiO{sub 2}-photocatalytic degradation of phenol. (orig.)

  4. Process for removing halogenated aliphatic and aromatic compounds from petroleum products

    Science.gov (United States)

    Googin, J.M.; Napier, J.M.; Travaglini, M.A.

    1983-09-20

    A process is described for removing halogenated aliphatic and aromatic compounds, e.g., polychlorinated biphenyls, from petroleum products by solvent extraction. The halogenated aliphatic and aromatic compounds are extracted from a petroleum product into a polar solvent by contacting the petroleum product with the polar solvent. The polar solvent is characterized by a high solubility for the extracted halogenated aliphatic and aromatic compounds, a low solubility for the petroleum product and considerable solvent power for polyhydroxy compound. The preferred polar solvent is dimethylformamide. A miscible compound, such as, water or a polyhydroxy compound, is added to the polar extraction solvent to increase the polarity of the polar extraction solvent. The halogenated aliphatic and aromatic compounds are extracted from the highly-polarized mixture of water or polyhydroxy compound and polar extraction solvent into a low polar or nonpolar solvent by contacting the water or polyhydroxy compound-polar solvent mixture with the low polar or nonpolar solvent. The halogenated aliphatic and aromatic compounds and the low polar or nonpolar solvent are separated by physical means, e.g., vacuum evaporation. The polar and nonpolar solvents are recovered from recycling. The process can easily be designed for continuous operation. Advantages of the process include that the polar solvent and a major portion of the nonpolar solvent can be recycled, the petroleum products are reclaimable and the cost for disposing of waste containing polychlorinated biphenyls is significantly reduced. 1 fig.

  5. Development of melting and casting process for Nb-Al intermetallic compounds and mechanical properties

    International Nuclear Information System (INIS)

    Kamata, Kinya; Degawa, Toru; Nagashima, Yoshinori

    1993-01-01

    The shaping methods of Nb-Al intermetallic compounds, especially melting and casting, have considerably different characteristics as compared with those for other metals and alloys. The authors have investigated melting and casting processes for Nb-Al compounds to develop precision casting processes for these intermetallics. Fundamental properties of Nb-Al compound castings have been also investigated for high temperature structural use in this work. An advanced Induction Skull Melting (ISM) furnace has been developed and the advantages of ISM have been recognized as a result of this study. The mechanical properties, such as hardness and compression strength, are dependent upon the Al content in Nb-Al binary compounds

  6. Precipitate hydrolysis process for the removal of organic compounds from nuclear waste slurries

    Science.gov (United States)

    Doherty, J.P.; Marek, J.C.

    1987-02-25

    A process for removing organic compounds from a nuclear waste slurry comprising reacting a mixture of radioactive waste precipitate slurry and an acid in the presence of a catalytically effective amount of a copper(II) catalyst whereby the organic compounds in the precipitate slurry are hydrolyzed to form volatile organic compounds which are separated from the reacting mixture. The resulting waste slurry, containing less than 10 percent of the original organic compounds, is subsequently blended with high level radioactive sludge land transferred to a vitrification facility for processing into borosilicate glass for long-term storage. 2 figs., 3 tabs.

  7. Various processes occurring in strong interactions between heavy ions: Compound nucleus formation, incomplete fusion, and quasifission

    International Nuclear Information System (INIS)

    Lefort, M.

    1975-01-01

    This paper deals with the problem of various deep processes occurring when two complex nuclei enter in collision. It is suggested that very deep inelastic processes may lead to either a compound nucleus or a composite system which shortly decays into two fission fragments (quasifission process). Particularly for heavy projectiles and targets, the predominant Coulomb potential inhibits the compound nucleus formation for low l waves. Then a critical angular momentum can be defined as the limit below which both processes (quasifission and compound nucleus formation) occur. For the heaviest nuclei, nearly all l waves below l) contribute to the quasifission phenomenon

  8. A new wire fabrication processing using high Ga content Cu-Ga compound in V3Ga compound superconducting wire

    International Nuclear Information System (INIS)

    Hishinuma, Yoshimitsu; Nishimura, Arata; Kikuchi, Akihiro; Iijima, Yasuo; Takeuchi, Takao

    2007-01-01

    A superconducting magnet system is also one of the important components in an advanced magnetic confinement fusion reactor. Then it is required to have a higher magnetic field property to confine and maintain steady-sate burning deuterium (D)-tritium (T) fusion plasma in the large interspace during the long term operation. Burning plasma is sure to generate 14 MeV fusion neutrons during deuterium-tritium reaction, and fusion neutrons will be streamed and penetrated to superconducting magnet through large ports with damping neutron energy. Therefore, it is necessary to consider carefully not only superconducting property but also neutron irradiation property in superconducting materials for use in a future fusion reactor, and a 'low activation and high field superconducting magnet' will be required to realize the fusion power plant beyond International Thermonuclear Experimental Reactor (ITER). V-based superconducting material has a much shorter decay time of induced radioactivity compared with the Nb-based materials. We thought that the V 3 Ga compound was one of the most promising materials for the 'low activation and higher field superconductors' for an advanced fusion reactor. However, the present critical current density (J c ) property of V 3 Ga compound wire is insufficient for apply to fusion magnet applications. We investigated a new route PIT process using a high Ga content Cu-Ga compound in order to improve the superconducting property of the V 3 Ga compound wire. (author)

  9. Food processing strategies to enhance phenolic compounds bioaccessibility and bioavailability in plant-based foods.

    Science.gov (United States)

    Ribas-Agustí, Albert; Martín-Belloso, Olga; Soliva-Fortuny, Robert; Elez-Martínez, Pedro

    2017-06-13

    Phenolic compounds are important constituents of plant-based foods, as their presence is related to protective effects on health. To exert their biological activity, phenolic compounds must be released from the matrix during digestion in an absorbable form (bioaccessible) and finally absorbed and transferred to the bloodstream (bioavailable). Chemical structure and matrix interactions are some food-related factors that hamper phenolic compounds bioaccessibility and bioavailability, and that can be counteracted by food processing. It has been shown that food processing can induce chemical or physical modifications in food that enhance phenolic compounds bioaccessibility and bioavailability. These changes include: (i) chemical modifications into more bioaccessible and bioavailable forms; (ii) cleavage of covalent or hydrogen bonds or hydrophobic forces that attach phenolic compounds to matrix macromolecules; (iii) damaging microstructural barriers such as cell walls that impede the release from the matrix; and (iv) create microstructures that protect phenolic compounds until they are absorbed. Indeed, food processing can produce degradation of phenolic compounds, however, it is possible to counteract it by modulating the operating conditions in favor of increased bioaccessibility and bioavailability. This review compiles the current knowledge on the effects of processing on phenolic compounds bioaccessibility or bioavailability, while suggesting new guidelines in the search of optimal processing conditions as a step forward towards the design of healthier foods.

  10. Reverse Osmosis Processing of Organic Model Compounds and Fermentation Broths

    National Research Council Canada - National Science Library

    Diltz, Robert; Henley, Michael V; Marolla, Theodore V; Li, Lixiong

    2006-01-01

    .... The actual fermentation broth obtained from a continuous-flow biohydrogen process was treated by the RO system under the operating conditions similar to those used in the baseline tests, resulting in greater...

  11. Luminescence and energy transfer processes in rare earth compounds

    International Nuclear Information System (INIS)

    Vliet, J.P.M. van.

    1989-01-01

    In this thesis some studies are presented of the luminescence and energy transfer in compounds containing Eu 3+ , Pr 3+ and Gd 3+ ions. Ch. 2 deals with the energy migration in the system Gd 1 - xEu x(IO 3) 3. In ch 3 the luminescence properties of the Pr 3+ ion in the system La 1 - xPr xMgAl 1 10 1 9 are reported. Ch. 4 discusses the luminescence properties of alkali europium double tungstates and molybdates AEuW 20 8 and AEuMo 20 * (A + = alkali metal atom). The luminiscence and energy migration characteristics of the isostructural system LiGd 1 - xEu xF 4 and Gd 1 - xEu xNbO 4 are reported in ch. 5. In ch. 6 the mechanism of energy migration in (La,Gd)AlO 3 and (Gd,Eu)AlO 3 is discussed. Ch. 7 deals with the system Na 5(Gd,Eu) (WO 4) 4. In ch. 8 the luminescence and energy transfer properties of two europium tellurite anti-glass phases are reported. The two phases are Eu 1 . 7 9TeO x, which has a pseudotetragonal structure, and Eu 1 . 0 6TeO x, which has a monoclinic, ordered structure. (author). 201 refs.; 39 figs.; 8 tabs

  12. Building Asphalt Pavement with SBS-based Compound Added Using a Dry Process in Greenland

    DEFF Research Database (Denmark)

    Lee, Hosin; Kim, Yongjoo; Geisler, Nivi

    2009-01-01

    PMA where it is formulated to melt and blend with asphalt quickly during a batch mixing process. The main objectives of this study are to (1) build asphalt pavement using asphalt mixtures with SBS-based compound added using a “dry” process at the batch plant and (2) evaluate its performance under......-based compound seemed to affect the asphalt mix to become more flexible under the heavy loads. By adding SBS-based compound to asphalt mixtures using a “dry” process, it is expected that the pavement would become more resistant to rutting than a typical asphalt mixture used in Greenland while enduring its arctic...

  13. Asymptotic behavior of local times of compound Poisson processes with drift in the infinite variance case

    NARCIS (Netherlands)

    Lambert, A.; Simatos, F.

    2015-01-01

    Consider compound Poisson processes with negative drift and no negative jumps, which converge to some spectrally positive Lévy process with nonzero Lévy measure. In this paper, we study the asymptotic behavior of the local time process, in the spatial variable, of these processes killed at two

  14. Asymptotic behavior of local times of compound Poisson processes with drift in the infinite variance case

    NARCIS (Netherlands)

    Lambert, A.; Simatos, F.

    2012-01-01

    Consider compound Poisson processes with negative drift and no negative jumps, which converge to some spectrally positive L\\'evy process with non-zero L\\'evy measure. In this paper we study the asymptotic behavior of the local time process, in the spatial variable, of these processes killed at two

  15. Structural changes in the ordering processes of macromolecular compounds

    International Nuclear Information System (INIS)

    Kobayashi, M.; Tashiro, K.

    1998-01-01

    In order to clarify the microscopically-viewed relationship between the conformational ordering process and the aggregation process of the macromolecular chains in the phase transitions from melt to solid or from solution to gel, the time-resolved Fourier-transform infrared spectra and small-angle X-ray or neutron scattering data have been analyzed in an organized manner. Two concrete examples were presented. (1) In the gelation phenomenon of syndiotactic polystyrene-organic solvent system, the ordered TTGG conformation is formed and develops with time. This conformational ordering is accelerated by the aggregation of these chain segments, resulting in the formation of macroscopic gel network. (2) In the isothermal crystallization process from the melt of polyethylene, the following ordering mechanism was revealed. The conformationally-disordered short trans conformers appear at first in the random coils of the melt. These disordered trans sequences grow to longer and more regular trans sequences of the orthorhombic-type crystal and then the isolated lamellae are formed. Afterwards, the stacked lamellar structure is developed without change of lamellar thickness but with small decrease in the long period, indicating an insertion of new lamellae between the already produced lamellar layers

  16. Process for the manufacture of a superconductor with an intermetallic compound

    International Nuclear Information System (INIS)

    Wilhelm, M.

    1980-01-01

    A superconductor with a superconducting intermetallic compound consisting of at least two elements can be manufactured by producing a conductor preproduct with a first component containing one element of the compound and a second component consisting of a carrier metal and the remaining element or elements of the alloy containing the compound, and by heat treating the conductor preproduct, so that the compound is formed by the reaction of the element of the first compound with the remaining element or elements of the second compound. In such a superconductor, one tries to increase the effective current density and critical current. The invention states that the heat treatment should be carried out in a hydrogen atmosphere. Superconductors produced by this process can be used for superconductor devices whose magnetic fields have a flux density above 10 Tesla. (orig.) [de

  17. Selective extraction of cesium: from compound to process

    International Nuclear Information System (INIS)

    Simon, N.; Eymard, S.; Tournois, B.; Dozol, J.F.

    2000-01-01

    Under the French law of 30 December 1991 on nuclear waste management, research is conducted to recover long-lived fission products from high-level radioactive effluents generated by spent fuel reprocessing, in order to destroy them by transmutation or encapsulate them in specific matrices. Cesium extraction with mono and bis-crown calix(4)arenes (Frame 1) is a candidate for process development. These extractants remove cesium from highly acidic or basic pH media even with high salinity. A real raffinate was treated in 1994 in a hot cell to extract cesium with a calix-crown extractant. The success of this one batch experiment confirmed the feasibility of cesium decontamination from high-level liquid waste. It was then decided to develop a process flowchart to extract cesium selectively from high-level raffinate, to be included in the general scheme of long-lived radionuclide partitioning. It was accordingly decided to develop a process based on liquid-liquid extraction and hence optimize a calixarene/diluent solvent according to: - hydraulic properties: density, viscosity, interfacial tension, - chemical criteria: sufficient cesium extraction (depending on the diluent), kinetics, third phase elimination... New mono-crown-calixarenes branched with long aliphatic groups (Frame 2) were designed to be soluble in aliphatic diluents. To prevent third phase formation associated with nitric acid extraction, the addition of modifiers (alcohol, phosphate and amide) in the organic phase was tested (Frame 3). Table 1 shows examples of calixarene/diluent systems suitable for a process flowchart, and Figure 2 provides data on cesium extraction with these new systems. Alongside these improvements, a system based on a modified 1,3-di(n-octyl-oxy)2,4-calix[4]arene crown and a modified diluent was also developed, considering a mixed TPH/NPHE system as the diluent, where TPH (hydrogenated tetra propylene) is a common aliphatic industrial solvent and NPHE is nitrophenyl

  18. Characterization and extraction of volatile compounds from pineapple (Ananas comosus L. Merril processing residues

    Directory of Open Access Journals (Sweden)

    Lília Calheiros de Oliveira Barretto

    2013-12-01

    Full Text Available The aim of this study was to extract and identify volatile compounds from pineapple residues generated during concentrated juice processing. Distillates of pineapple residues were obtained using the following techniques: simple hydrodistillation and hydrodistillation by passing nitrogen gas. The volatile compounds present in the distillates were captured by the solid-phase microextraction technique. The volatile compounds were identified in a system of high resolution gas chromatography system coupled with mass spectrometry using a polyethylene glycol polar capillary column as stationary phase. The pineapple residues constituted mostly of esters (35%, followed by ketones (26%, alcohols (18%, aldehydes (9%, acids (3% and other compounds (9%. Odor-active volatile compounds were mainly identified in the distillate obtained using hydrodistillation by passing nitrogen gas, namely decanal, ethyl octanoate, acetic acid, 1-hexanol, and ketones such as γ-hexalactone, γ-octalactone, δ-octalactone, γ-decalactone, and γ-dodecalactone. This suggests that the use of an inert gas and lower temperatures helped maintain higher amounts of flavor compounds. These data indicate that pineapple processing residue contained important volatile compounds which can be extracted and used as aroma enhancing products and have high potential for the production of value-added natural essences.

  19. Post-process intensification of photographic silver images, using radioactive compounds

    International Nuclear Information System (INIS)

    1979-01-01

    A method of post-process intensification of silver images on a developed and fixed photographic film or plate is described, comprising the steps of (a) converting silver of the developed film or plate to a radioactive compound by contracting the film or plate with an aqueous alkaline solution of an organo-S 35 compound which reacts selectively with silver in a photographic film or plate; (b) placing the film or plate treated in step (a) in direct contact with a receiver film which is sensitive to beta radiation whereby the receiver film is exposed by radiation from the radioactive compound; and (c) developing and fixing the resulting intensified receiver film. (author)

  20. Controls on the Environmental Fate of Compounds Controlled by Coupled Hydrologic and Reactive Processes

    Science.gov (United States)

    Hixson, J.; Ward, A. S.; McConville, M.; Remucal, C.

    2017-12-01

    Current understanding of how compounds interact with hydrologic processes or reactive processes have been well established. However, the environmental fate for compounds that interact with hydrologic AND reactive processes is not well known, yet critical in evaluating environmental risk. Evaluations of risk are often simplified to homogenize processes in space and time and to assess processes independently of one another. However, we know spatial heterogeneity and time-variable reactivities complicate predictions of environmental transport and fate, and is further complicated by the interaction of these processes, limiting our ability to accurately predict risk. Compounds that interact with both systems, such as photolytic compounds, require that both components are fully understood in order to predict transport and fate. Release of photolytic compounds occurs through both unintentional releases and intentional loadings. Evaluating risks associated with unintentional releases and implementing best management practices for intentional releases requires an in-depth understanding of the sensitivity of photolytic compounds to external controls. Lampricides, such as 3-trifluoromethyl-4-nitrophenol (TFM), are broadly applied in the Great Lakes system to control the population of invasive sea lamprey. Over-dosing can yield fish kills and other detrimental impacts. Still, planning accounts for time of passage and dilution, but not the interaction of the physical and chemical systems (i.e., storage in the hyporheic zone and time-variable decay rates). In this study, we model a series of TFM applications to test the efficacy of dosing as a function of system characteristics. Overall, our results demonstrate the complexity associated with photo-sensitive compounds through stream-hyporheic systems, and highlight the need to better understand how physical and chemical systems interact to control transport and fate in the environment.

  1. Kinetic particularities of strained alicyclic compounds formation in catalytic methanol to hydrocarbon transformation process

    OpenAIRE

    Doluda V.; Brovko R.; Giniatullina N.; Sulman M.

    2017-01-01

    The catalytic transformation of methanol into hydrocarbons is a complex chemical process, accompanied by chain parallel chemical transformation reactions. The most valuable products of the methanol to hydrocarbons catalytic transformation reaction are the strained hydrocarbons — cyclopropane derivatives. These compounds can be used as a high-energy fuel, and also as a valuable chemical raw material. However, the yield of strained compounds in methanol to hydrocarbons catalytic transformation ...

  2. Centrifugal fragmentation of a dinuclear system in the process of its evolution to the compound nucleus

    International Nuclear Information System (INIS)

    Volkov, V.V.

    2005-01-01

    The physical content of centrifugal fragmentation is discussed. It is a specific nuclear process which is realized in the evolution of a dinuclear system into a compound nucleus at large angular momenta and large mass asymmetry of the system. The dinuclear system concept which describes the process of the compound nucleus formation in heavy ion reactions predicts the possibility of centrifugal fragmentation. Experimental data giving evidence of the realization of this nuclear process are given. A possible scheme of the centrifugal fragmentation model is discussed

  3. Centrifugal Fragmentation of a Dinuclear System in the Process of Its Evolution to the Compound Nucleus

    CERN Document Server

    Volkov, V V

    2005-01-01

    The physical content of centrifugal fragmentation is discussed. It is a specific nuclear process which is realized in the evolution of a dinuclear system into a compound nucleus at large angular momenta and large mass asymmetry of the system. The dinuclear system concept which describes the process of the compound nucleus formation in heavy ion reactions predicts the possibility of centrifugal fragmentation. Experimental data giving evidence of the realization of this nuclear process are given. A possible scheme of the centrifugal fragmentation model is discussed.

  4. Effects of Processing Conditions During Manufacture on Retronasal-Aroma Compounds from a Milk Coffee Drink.

    Science.gov (United States)

    Ikeda, Michio; Akiyama, Masayuki; Hirano, Yuta; Miyazi, Kazuhiro; Kono, Masaya; Imayoshi, Yuriko; Iwabuchi, Hisakatsu; Onodera, Takeshi; Toko, Kiyoshi

    2018-03-01

    To develop a ready-to-drink (RTD) milk coffee retaining the original coffee flavor, the effects of processing conditions during manufacture on retronasal-arma (RA) compounds from the milk coffee were investigated by gas chromatography-mass spectrometry using an RA simulator (RAS). Thirteen of 46 detected compounds in the RAS effluent (RAS compounds) decreased significantly following pH adjustment of coffee (from pH 5.1 to 6.8) and 5 compounds increased. RAS compounds from coffee tended to decrease through the pH adjustment and subsequent sterilization. Significantly higher amounts of 13 RAS compounds were released from the milk coffee produced using a blending-after-sterilization (BAS) process without the pH adjustment than from that using a blending-before-sterilization (BBS) process with the pH adjustment. In BAS-processed milk coffee, significantly lower amounts of 8 high-volatility compounds and 1H-pyrrole were released from coffee containing infusion-sterilized (INF) milk than from coffee containing plate-sterilized (PLT) milk, whereas 3 low-volatility compounds were released significantly more from coffee using PLT milk. Principal component analysis revealed that the effect of the manufacturing process (BAS, BBS, or homemade (blending unsterilized coffee without pH adjustment with sterilized milk)) on milk coffee volatiles was larger than that of the sterilization method (INF or PLT) for milk, and that the sterilization method could result in different RAS volatile characteristics in BAS and homemade processes. In conclusion, a BAS process was found to be superior to a BBS process for the manufacture of an RTD milk coffee that retains volatile characteristics similar to that of a homemade milk coffee. Ready-to-drink (RTD) milk coffee manufactured using the conventional blending-before-sterilization process does not retain its original coffee flavor due to pH adjustment of the coffee during the process. The new blending-after-sterilization (BAS) process

  5. Industrial processing effects on phenolic compounds in sour cherry (Prunus cerasus L.) fruit

    NARCIS (Netherlands)

    Toydemir, G.; Capanoglu, E.; Gomez-Roldan, M.V.; Vos, de R.C.H.; Boyacioglu, D.; Hall, R.D.; Beekwilder, M.J.

    2013-01-01

    The processed juice (or nectar) of the sour cherry, Prunus cerasus L., is widely consumed in the Balkan region and Turkey. Sour cherry is known to be rich in polyphenolic compounds, such as anthocyanins and procyanidins. In this work, the effects of processing of sour cherry fruit to nectar on

  6. Hazard rate model and statistical analysis of a compound point process

    Czech Academy of Sciences Publication Activity Database

    Volf, Petr

    2005-01-01

    Roč. 41, č. 6 (2005), s. 773-786 ISSN 0023-5954 R&D Projects: GA ČR(CZ) GA402/04/1294 Institutional research plan: CEZ:AV0Z10750506 Keywords : couting process * compound process * Cox regression model * intensity Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 0.343, year: 2005

  7. Homogeneous Discrete Time Alternating Compound Renewal Process: A Disability Insurance Application

    Directory of Open Access Journals (Sweden)

    Guglielmo D’Amico

    2015-01-01

    Full Text Available Discrete time alternating renewal process is a very simple tool that permits solving many real life problems. This paper, after the presentation of this tool, introduces the compound environment in the alternating process giving a systematization to this important tool. The claim costs for a temporary disability insurance contract are presented. The algorithm and an example of application are also provided.

  8. Evaluation of phenolic compounds in mate (Ilex paraguariensis) processed by gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Furgeri, C.; Nunes, T.C.F.; Fanaro, G.B. [Instituto de Pesquisas Energeticas Nucleares, IPEN-CNEN/SP, Centro de Tecnologia das Radiacoes-Laboratory de Deteccao de Alimentos Irradiados, Av. Professor Lineu Prestes, 2242, Cidade Universitaria, CEP: 05508-900 Sao Paulo (Brazil); Souza, M.F.F.; Bastos, D.H.M. [Faculdade de Saude Publica, FSP/USP, Departamento de Nutricao-Av. Dr. Arnaldo, 715, CEP: 01246-904 Sao Paulo (Brazil); Villavicencio, A.L.C.H. [Instituto de Pesquisas Energeticas Nucleares, IPEN-CNEN/SP, Centro de Tecnologia das Radiacoes-Laboratory de Deteccao de Alimentos Irradiados, Av. Professor Lineu Prestes, 2242, Cidade Universitaria, CEP: 05508-900 Sao Paulo (Brazil)], E-mail: villavic@ipen.br

    2009-07-15

    The radiation food processing has been demonstrating great effectiveness in the attack of pathogenic agents, while little compromising nutritional value and sensorial properties of foods. The mate (Ilex paraguariensis), widely consumed product in South America, generally in the form of infusions with hot or cold water, calls of chimarrao or terere, it is cited in literature as one of the best sources phenolic compounds. The antioxidants action of these constituent has been related to the protection of the organism against the free radicals, generated in alive, currently responsible for the sprouting of some degenerative illness as cancer, arteriosclerosis, rheumatic arthritis and cardiovascular clutters among others. The objective of that work was to evaluate the action of the processing for gamma radiation in phenolic compounds of terere beverage in the doses of 0, 3, 5, 7 and 10 kGy. The observed results do not demonstrate significant alterations in phenolic compounds of terere beverage processed by gamma radiation.

  9. Evaluation of phenolic compounds in mate (Ilex paraguariensis) processed by gamma radiation

    International Nuclear Information System (INIS)

    Furgeri, C.; Nunes, T.C.F.; Fanaro, G.B.; Souza, M.F.F.; Bastos, D.H.M.; Villavicencio, A.L.C.H.

    2009-01-01

    The radiation food processing has been demonstrating great effectiveness in the attack of pathogenic agents, while little compromising nutritional value and sensorial properties of foods. The mate (Ilex paraguariensis), widely consumed product in South America, generally in the form of infusions with hot or cold water, calls of chimarrao or terere, it is cited in literature as one of the best sources phenolic compounds. The antioxidants action of these constituent has been related to the protection of the organism against the free radicals, generated in alive, currently responsible for the sprouting of some degenerative illness as cancer, arteriosclerosis, rheumatic arthritis and cardiovascular clutters among others. The objective of that work was to evaluate the action of the processing for gamma radiation in phenolic compounds of terere beverage in the doses of 0, 3, 5, 7 and 10 kGy. The observed results do not demonstrate significant alterations in phenolic compounds of terere beverage processed by gamma radiation.

  10. A process for producing lignin and volatile compounds from hydrolysis liquor.

    Science.gov (United States)

    Khazraie, Tooran; Zhang, Yiqian; Tarasov, Dmitry; Gao, Weijue; Price, Jacquelyn; DeMartini, Nikolai; Hupa, Leena; Fatehi, Pedram

    2017-01-01

    Hot water hydrolysis process is commercially applied for treating wood chips prior to pulping or wood pellet production, while it produces hydrolysis liquor as a by-product. Since the hydrolysis liquor is dilute, the production of value-added materials from it would be challenging. In this study, acidification was proposed as a viable method to extract (1) furfural and acetic acid from hot water hydrolysis liquor and (2) lignin compounds from the liquor. The thermal properties of the precipitates made from the acidification of hydrolysis liquor confirmed the volatile characteristics of precipitates. Membrane dialysis was effective in removing inorganic salts associated with lignin compounds. The purified lignin compounds had a glass transition temperature (Tg) of 180-190 °C, and were thermally stable. The results confirmed that lignin compounds present in hot water hydrolysis liquor had different characteristics. The acidification of hydrolysis liquor primarily removed the volatile compounds from hydrolysis liquor. Based on these results, a process for producing purified lignin and precipitates of volatile compounds was proposed.

  11. Effect of processing and storage time on the contents of organosulfur compounds in pickled blanched garlic.

    Science.gov (United States)

    Beato, Victor Manuel; Sánchez, Antonio Higinio; de Castro, Antonio; Montaño, Alfredo

    2012-04-04

    The influence of processing, with and without fermentation, on the contents of organosulfur compounds, namely, γ-glutamyl peptides, S-alk(en)yl-L-cysteine sulfoxides (ACSOs), and S-allyl-L-cysteine (SAC), in pickled blanched garlic was evaluated. For each processing type, the effect of the preservation method and storage time was also analyzed. Blanching in hot water (90 °C for 5 min) hardly affected the individual organosulfur compound content. The fermentation and packing steps negatively affected the levels of all compounds except for SAC. The content of this compound increased during storage at room temperature whereas γ-glutamyl peptides and ACSOs were degraded to various extents. The pasteurization treatment itself had no significant effect on the concentrations of organosulfur compounds. Use of the corresponding fermentation brine in the case of the fermented product in conjunction with refrigerated storage was found to be the best method to preserve the levels of organosulfur compounds in pickled garlic stored for up to one year.

  12. Powder metallurgical processing of magnetostrictive materials based on rare earth-iron intermetallic compounds

    International Nuclear Information System (INIS)

    Malekzadeh, M.

    1978-01-01

    Procedures are described for fabrication of high density rare earth-iron magnetostrictive compounds by powder metallurgical techniques. The fabrication involves a sequence of steps which includes preparing the pre-alloyed compounds, pulverizing them into a fine powder, compacting in suitable sizes and shapes, and sintering. Samples prepared by these procedures are carefully characterized by scanning electron microscopy, x-ray diffraction, dilatometry, and magnetic measurements. Process steps are found to exert important influences upon densities, microstructure and magnetic properties attained after densification. Investigations on a number of these process steps, including milling time and medium, sintering, and magnetic powder alignment are described

  13. Character Decomposition and Transposition Processes in Chinese Compound Words Modulates Attentional Blink.

    Science.gov (United States)

    Cao, Hongwen; Gao, Min; Yan, Hongmei

    2016-01-01

    The attentional blink (AB) is the phenomenon in which the identification of the second of two targets (T2) is attenuated if it is presented less than 500 ms after the first target (T1). Although the AB is eliminated in canonical word conditions, it remains unclear whether the character order in compound words affects the magnitude of the AB. Morpheme decomposition and transposition of Chinese two-character compound words can provide an effective means to examine AB priming and to assess combinations of the component representations inherent to visual word identification. In the present study, we examined the processing of consecutive targets in a rapid serial visual presentation (RSVP) paradigm using Chinese two-character compound words in which the two characters were transposed to form meaningful words or meaningless combinations (reversible, transposed, or canonical words). We found that when two Chinese characters that form a compound word, regardless of their order, are presented in an RSVP sequence, the likelihood of an AB for the second character is greatly reduced or eliminated compared to when the two characters constitute separate words rather than a compound word. Moreover, the order of the report for the two characters is more likely to be reversed when the normal order of the two characters in a compound word is reversed, especially when the interval between the presentation of the two characters is extremely short. These findings are more consistent with the cognitive strategy hypothesis than the resource-limited hypothesis during character decomposition and transposition of Chinese two-character compound words. These results suggest that compound characters are perceived as a unit, rather than two separate words. The data further suggest that readers could easily understand the text with character transpositions in compound words during Chinese reading.

  14. Influence of gamma irradiation on phenolic compounds of minimally processed baby carrots

    International Nuclear Information System (INIS)

    Hirashima, Fabiana K.; Fabbri, Adriana D.T.; Sagretti, Juliana M.A.; Nunes, Thaise C.F.; Sabato, Suzy F.; Galvao, Natascha S.; Lanfer-Marquez, Ursula M.

    2013-01-01

    Consumption of fresh fruits and vegetables provide several health benefits including risk reduction of oxidative stress-related diseases. These benefits have been associated with bioactive compounds, mainly phenolic compounds. Minimally processed products are a growing segment in food retail establishments due its practicality and convenience without significantly altering fresh-like characteristics. To extend the shelf life of these products, an application of ionizing radiation is an alternative, based on a physical and non-thermal method of preservation. The effect of irradiation on phenolic compounds of minimally processed baby carrots have not been reported in literature yet. The aim of this study was to evaluate the levels of phenolic compounds in baby carrots after the irradiation process. Samples of minimally processed baby carrots were purchased at a local supermarket and irradiated with doses of 0.5 and 1.0 kGy. Phenolic compounds were extracted from shredded carrots with MeOH and analyzed spectrophotometrically by the Folin Ciocalteau method using a gallic acid standard curve. The results showed that the phenolic contents decreased significantly (p<0.05) with increasing radiation dose. In non-irradiated baby carrots (control), the levels of phenolic compounds were about 330 μg eq. gallic acid/g, while irradiated samples with 0.5 kGy, showed an approximately 10% reduction when compared with the control. An irradiation dose of 1.0 kGy caused a loss of 20%. Although the radiation has affected the phenolic content, the process seems to be interesting by maintaining their fresh-like characteristics. (author)

  15. Influence of gamma irradiation on phenolic compounds of minimally processed baby carrots

    Energy Technology Data Exchange (ETDEWEB)

    Hirashima, Fabiana K.; Fabbri, Adriana D.T.; Sagretti, Juliana M.A.; Nunes, Thaise C.F.; Sabato, Suzy F., E-mail: fmayumi@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Galvao, Natascha S.; Lanfer-Marquez, Ursula M., E-mail: lanferum@usp.br [Universidade de Sao Paulo (FCF/USP), SP (Brazil). Faculdade de Ciencias Farmaceuticas

    2013-07-01

    Consumption of fresh fruits and vegetables provide several health benefits including risk reduction of oxidative stress-related diseases. These benefits have been associated with bioactive compounds, mainly phenolic compounds. Minimally processed products are a growing segment in food retail establishments due its practicality and convenience without significantly altering fresh-like characteristics. To extend the shelf life of these products, an application of ionizing radiation is an alternative, based on a physical and non-thermal method of preservation. The effect of irradiation on phenolic compounds of minimally processed baby carrots have not been reported in literature yet. The aim of this study was to evaluate the levels of phenolic compounds in baby carrots after the irradiation process. Samples of minimally processed baby carrots were purchased at a local supermarket and irradiated with doses of 0.5 and 1.0 kGy. Phenolic compounds were extracted from shredded carrots with MeOH and analyzed spectrophotometrically by the Folin Ciocalteau method using a gallic acid standard curve. The results showed that the phenolic contents decreased significantly (p<0.05) with increasing radiation dose. In non-irradiated baby carrots (control), the levels of phenolic compounds were about 330 μg eq. gallic acid/g, while irradiated samples with 0.5 kGy, showed an approximately 10% reduction when compared with the control. An irradiation dose of 1.0 kGy caused a loss of 20%. Although the radiation has affected the phenolic content, the process seems to be interesting by maintaining their fresh-like characteristics. (author)

  16. Identification and Quantification of Volatile Compounds Found in Vinasses from Two Different Processes of Tequila Production

    Directory of Open Access Journals (Sweden)

    Elizabeth Rodríguez-Félix

    2018-02-01

    Full Text Available Vinasses are the main byproducts of ethanol distillation and distilled beverages worldwide and are generated in substantial volumes. Tequila vinasses (TVs could be used as a feedstock for biohydrogen production through a dark fermentative (DF process due to their high content of organic matter. However, TV components have not been previously assayed in order to evaluate if they may dark ferment. This work aimed to identify and quantify volatile compounds (VC in TV and determine if the VC profile depends upon the type of production process (whether the stems were initially cooked or not. TVs were sampled from 3 agave stems with a not-cooking (NC process, and 3 agave stems with a cooking (C process, and volatile compounds were determined by gas chromatography coupled with mass spectrometry (GC–MS. A total of 111 volatile compounds were identified, the TV from the cooking process (C showed the higher presence of furanic compounds (furfural and 5-(hydroxymethyl furfural and organic acids (acetic acid and butyric acid, which have been reported as potential inhibitors for DF. To our knowledge, this is the first description of the VC composition from TVs. This study could serve as a base for further investigations related to vinasses from diverse sources.

  17. [Analysis of variation of monoterpene glycosides and polyhydroxy compounds in paeoniae radix alba during preliminary processing].

    Science.gov (United States)

    Xu, Yuan; Liu, Pei; Yan, Hui; Qian, Da-Wei; Duan, Jin-Ao

    2014-05-01

    To investigate variation of monoterpene glycosides and polyhydroxy compounds in Paeoniae Radix Alba dried by different processing methods. The crude drugs were processed sequentially as washed, removed the head, tail, fine roots and dried. The samples were divided into eight groups by whether peeled and decocted or not. Each group was dried by 35, 45, 60, 80,100, 120 degrees C, sun-dried and shade-dried. HPLC-PDA method was adopted to determine the content of monoterpene glycosides compounds (paeoniflorin alibiflorin, oxypaeoniflorin and benzoylpaeoniflorin), polyhydroxy compounds (catechin and gallic acid) and benzoic acid. Chromatographic conditions: Phecad C18 column (250 mm x 4.6 mm, 5 microm). A principal component analysis (PCA) method was used subsequently to get data processed. The retained content of seven constituents decreased in those peeled crude drug, and after cooked, monoterpene glycosides and polyhydroxy compounds increased while the benzoic acid decreased. It was believed that rele- vant enzymes were inactivated while being cooked so that drying temperature showed little influence on the biotransformation. Contents of effective ingredients in Paeoniae Radix Alba are influenced by drying processing. The preferable method shows to be that crude drug should be cooked before being peeled and dried. As a matter of processing convtence, it is suggested to be peeled and sliced before being dried.

  18. Blood compounds irradiation process: assessment of absorbed dose using Fricke and Thermoluminescent dosimetric systems

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Gabriela de Amorim; Squair, Peterson Lima; Pinto, Fausto Carvalho; Belo, Luiz Claudio Meira; Grossi, Pablo Andrade [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN-CNEN/MG), Belo Horizonte, MG (Brazil)], e-mail: gas@cdtn.br, e-mail: pls@cdtn.br, e-mail: fcp@cdtn.br, e-mail: lcmb@cdtn.br, e-mail: pabloag@cdtn.br

    2009-07-01

    The assessment of gamma absorbed doses in irradiation facilities allows the quality assurance and control of the irradiation process. The liability of dose measurements is assign to the metrological procedures adopted including the uncertainty evaluation. Fricke and TLD 800 dosimetric systems were used to measure absorbed dose in the blood compounds using the methodology presented in this paper. The measured absorbed doses were used for evaluating the effectiveness of the irradiation procedure and the gamma dose absorption inside the irradiation room of a gamma irradiation facility. The radiation eliminates the functional and proliferative capacities of donor T-lymphocytes, preventing Transfusion associated graft-versus-host disease (TA-GVHD), a possible complication of blood transfusions. The results show the applicability of such dosimetric systems in quality assurance programs, assessment of absorbed doses in blood compounds and dose uniformity assign to the blood compounds irradiation process by dose measurements in a range between 25 Gy and 100 Gy. (author)

  19. Blood compounds irradiation process: assessment of absorbed dose using Fricke and Thermoluminescent dosimetric systems

    International Nuclear Information System (INIS)

    Soares, Gabriela de Amorim; Squair, Peterson Lima; Pinto, Fausto Carvalho; Belo, Luiz Claudio Meira; Grossi, Pablo Andrade

    2009-01-01

    The assessment of gamma absorbed doses in irradiation facilities allows the quality assurance and control of the irradiation process. The liability of dose measurements is assign to the metrological procedures adopted including the uncertainty evaluation. Fricke and TLD 800 dosimetric systems were used to measure absorbed dose in the blood compounds using the methodology presented in this paper. The measured absorbed doses were used for evaluating the effectiveness of the irradiation procedure and the gamma dose absorption inside the irradiation room of a gamma irradiation facility. The radiation eliminates the functional and proliferative capacities of donor T-lymphocytes, preventing Transfusion associated graft-versus-host disease (TA-GVHD), a possible complication of blood transfusions. The results show the applicability of such dosimetric systems in quality assurance programs, assessment of absorbed doses in blood compounds and dose uniformity assign to the blood compounds irradiation process by dose measurements in a range between 25 Gy and 100 Gy. (author)

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

    Science.gov (United States)

    Xiao, Wei; Wang, Dihua

    2014-05-21

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

  1. On the (R,s,Q) Inventory Model when Demand is Modelled as a Compound Process

    NARCIS (Netherlands)

    Janssen, F.B.S.L.P.; Heuts, R.M.J.; de Kok, T.

    1996-01-01

    In this paper we present an approximation method to compute the reorder point s in a (R; s; Q) inventory model with a service level restriction, where demand is modelled as a compound Bernoulli process, that is, with a xed probability there is positive demand during a time unit, otherwise demand is

  2. Effect of Germination and Fermentation Process on the Antioxidant Compounds of Quinoa Seeds.

    Science.gov (United States)

    Carciochi, Ramiro Ariel; Galván-D'Alessandro, Leandro; Vandendriessche, Pierre; Chollet, Sylvie

    2016-12-01

    Quinoa (Chenopodium quinoa) seed has gained a great interest in the last years, mainly due to its nutritional properties and its content of antioxidant substances with health-promoting properties in humans. In this work, the effect of germination time and fermentation on the levels of antioxidant compounds (ascorbic acid, tocopherol isomers and phenolic compounds) and antioxidant activity of quinoa seeds was evaluated. Fermentation was carried out naturally by the microorganisms present in the seeds or by inoculation with two Saccharomyces cerevisiae strains (used for baking and brewing). Ascorbic acid and total tocopherols were significantly increased (p ≤ 0.05) after 72 h of germination process in comparison with raw quinoa seeds, whilst fermentation caused a decrease in both types of compounds. Phenolic compounds and antioxidant capacity were improved using both bioprocesses, being this effect more noticeable for germination process (101 % of increase after three days of germination). Germination and fermentation proved to be desirable procedures for producing enriched ingredients with health-promoting antioxidant compounds in a natural way.

  3. Potential Signatures of Semi-volatile Compounds Associated With Nuclear Processing

    Energy Technology Data Exchange (ETDEWEB)

    Probasco, Kathleen M.; Birnbaum, Jerome C.; Maughan, A. D.

    2002-06-01

    Semi-volatile chemicals associated with nuclear processes (e.g., the reprocessing of uranium to produce plutonium for nuclear weapons, or the separation of actinides from processing waste streams), can provide sticky residues or signatures that will attach to piping, ducting, soil, water, or other surface media. Volatile compounds, that are more suitable for electro-optical sensing, have been well studied. However, the semi-volatile compounds have not been well documented or studied. A majority of these semi-volatile chemicals are more robust than typical gaseous or liquid chemicals and can have lifetimes of several weeks, months, or years in the environment. However, large data gaps exist concerning these potential signature compounds and more research is needed to fill these data gaps so that important signature information is not overlooked or discarded. This report investigates key semi-volatile compounds associated with nuclear separations, identifies available chemical and physical properties, and discusses the degradation products that would result from hydrolysis, radiolysis and oxidation reactions on these compounds.

  4. Bioactive compounds in pindo palm (Butia capitata) juice and in pomace resulting of the extraction process.

    Science.gov (United States)

    Jachna, Tiphaine J; Hermes, Vanessa S; Flôres, Simone H; Rios, Alessandro O

    2016-03-15

    Pindo palm (Butia capitata, Becc. 1916) is a tropical fruit native to South America and is relatively rich in bioactive compounds. It is often consumed as juice. The aim of this study was, first, to identify the degradation of these compounds by pasteurization and by cold storage (4 °C) of pindo palm juice. Physicochemical properties and concentrations of phenolic compounds, carotenoids and vitamin C have been evaluated on fresh and pasteurized juices. Moreover, another objective was to characterize the nutritional composition and the bioactive compounds of pindo palm pomace, the by-product of juice processing. The results demonstrated a degradation of carotenoids with pasteurization and a degradation of vitamin C with both pasteurization and cold storage of juices. Furthermore, the evaluation of pindo palm pomace showed that it is relatively rich in total phenols (20.06 g gallic acid equivalents kg(-1) dry matter) and in β-carotene (0.22 g kg(-1) dry matter). Thus, from the nutrition viewpoint, it does not seem interesting to pasteurize juice. On the other hand, extraction of carotenoids and phenolic compounds from the pomace appears to be a relevant process. © 2015 Society of Chemical Industry.

  5. Process engineering versus product engineering - A case study on volatile organic compounds removal

    DEFF Research Database (Denmark)

    Coutinho, João A.P.; Vilela, T.; Pereira, P.

    2005-01-01

    Three solutions for removing the dangerous volatile organic compound (VOC) xylene from an industrial coating process are presented and compared. Two of them are based on classical process engineering principles, i.e., development of separation-cleaning methods such as incineration and adsorption...... to the problem-need specified in the beginning of the project, but producing a novel formulation (chemical product design) represents a method that results to a completely xylene-free process which is environmentally and economically more interesting than those generated via the more traditional process...

  6. Ionic-Liquid-Mediated Extraction and Separation Processes for Bioactive Compounds: Past, Present, and Future Trends.

    Science.gov (United States)

    Ventura, Sónia P M; E Silva, Francisca A; Quental, Maria V; Mondal, Dibyendu; Freire, Mara G; Coutinho, João A P

    2017-05-24

    Ionic liquids (ILs) have been proposed as promising media for the extraction and separation of bioactive compounds from the most diverse origins. This critical review offers a compilation on the main results achieved by the use of ionic-liquid-based processes in the extraction and separation/purification of a large range of bioactive compounds (including small organic extractable compounds from biomass, lipids, and other hydrophobic compounds, proteins, amino acids, nucleic acids, and pharmaceuticals). ILs have been studied as solvents, cosolvents, cosurfactants, electrolytes, and adjuvants, as well as used in the creation of IL-supported materials for separation purposes. The IL-based processes hitherto reported, such as IL-based solid-liquid extractions, IL-based liquid-liquid extractions, IL-modified materials, and IL-based crystallization approaches, are here reviewed and compared in terms of extraction and separation performance. The key accomplishments and future challenges to the field are discussed, with particular emphasis on the major lacunas found within the IL community dedicated to separation processes and by suggesting some steps to overcome the current limitations.

  7. Centrifugal fragmentation of a dinuclear system in the process of its evolution toward a compound nucleus

    International Nuclear Information System (INIS)

    Volkov, V. V.

    2007-01-01

    The centrifugal fragmentation of a dinuclear system in the process of evolution toward a compound nucleus is examined. If the angular momentum in the collision of primary nuclei is quite high, centrifugal forces become dominant at the final stage of the evolution of the dinuclear system formed, causing the decay of this dinuclear system to two strongly asymmetric nuclear fragments. Experimental data in which this specific nuclear process manifests itself are presented. Centrifugal fragmentation makes it possible to reveal the cluster facet of the evolution of a dinuclear system toward a compound nucleus. The possibility of this fragmentation process is a logical consequence of the concept of a dinuclear system for the complete fusion of nuclei

  8. Generation of Maillard compounds from inulin during the thermal processing of Agave tequilana Weber Var. azul.

    Science.gov (United States)

    Mancilla-Margalli, Norma A; López, Mercedes G

    2002-02-13

    During the cooking process of Agave tequilana Weber var. azul to produce tequila, besides the hydrolysis of inulin to generate fermentable sugars, many volatiles, mainly Maillard compounds, are produced, most of which may have a significant impact on the overall flavor of tequila. Exudates (agave juice) from a tequila company were collected periodically, and color, Brix, fructose concentration, and reducing sugars were determined as inulin breakdown took place. Maillard compounds were obtained by extraction with CH(2)Cl(2), and the extracts were analyzed by GC-MS. Increments in color, Brix, and reducing sugars were observed as a function of time, but a decrease in fructose concentration was found. Many Maillard compounds were identified in the exudates, including furans, pyrans, aldehydes, and nitrogen and sulfur compounds. The most abundant Maillard compounds were methyl-2-furoate, 2,3-dihydroxy-3,5-dihydro-6-methyl-4(H)-pyran-4-one, and 5-(hydroxymethyl)furfural. In addition, a series of short- and long-chain fatty acids was also found. A large number of the volatiles in A. tequilana Weber var. azul were also detected in tequila extracts, and most of these have been reported as a powerful odorants, responsible for the unique tequila flavor.

  9. Lipid oxidation in baked products: impact of formula and process on the generation of volatile compounds.

    Science.gov (United States)

    Maire, Murielle; Rega, Barbara; Cuvelier, Marie-Elisabeth; Soto, Paola; Giampaoli, Pierre

    2013-12-15

    This paper investigates the effect of ingredients on the reactions occurring during the making of sponge cake and leading to the generation of volatile compounds related to flavour quality. To obtain systems sensitive to lipid oxidation (LO), a formulation design was applied varying the composition of fatty matter and eggs. Oxidation of polyunsaturated fatty acids (PUFA) and formation of related volatile compounds were followed at the different steps of cake-making. Optimised dynamic Solid Phase Micro Extraction was applied to selectively extract either volatile or semi-volatile compounds directly from the baking vapours. We show for the first time that in the case of alveolar baked products, lipid oxidation occurs very early during the step of dough preparation and to a minor extent during the baking process. The generation of lipid oxidation compounds depends on PUFA content and on the presence of endogenous antioxidants in the raw matter. Egg yolk seemed to play a double role on reactivity: protecting unsaturated lipids from oxidation and being necessary to generate a broad class of compounds of the Maillard reaction during baking and linked to the typical flavour of sponge cake. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Changes in Volatile Compounds of Chinese Luzhou-Flavor Liquor during the Fermentation and Distillation Process.

    Science.gov (United States)

    Ding, Xiaofei; Wu, Chongde; Huang, Jun; Zhou, Rongqing

    2015-11-01

    The aim of this study was to investigate the dynamic of volatile compounds in the Zaopei during the fermentation and distillation process by headspace solid-phase microextraction-gas chromatography mass spectrometry (HS-SPME-GCMS). Physicochemical properties analysis of Zaopei (fermented grains [FG], fermented grains mixed with sorghum [FGS], streamed grains [SG], and streamed grains mixed with Daqu [SGD]) showed distinct changes. A total number of 66 volatile compounds in the Zaopei were identified, in which butanoic acid, hexanoic acid, ethyl hexanoate, ethyl lactate, ethyl octanoate, hexyl hexanoate, ethyl hydrocinnamate, ethyl oleate, ethyl hexadecanoate, and ethyl linoleate were considered to be the dominant compounds due to their high concentrations. FG had the highest volatile compounds (112.43 mg/kg), which significantly decreased by 17.05% in the FGS, 67.12% in the SG, and 73.75% in the SGD. Furthermore, about 61.49% of volatile compounds of FGS were evaporated into raw liquor, whereas head, heart, and tail liquor accounted for 29.84%, 39.49%, and 30.67%, respectively. Each volatile class generally presented a decreasing trend, except for furans. Especially, the percentage of esters was 55.51% to 67.41% in the Zaopei, and reached 92.60% to 97.67% in the raw liquor. Principal component analysis based ordination of volatile compounds data segregated FGS and SGD samples. In addition, radar diagrams of the odor activity values suggested that intense flavor of fruit was weakened most from FG to SGD. The dynamic of volatile compounds in the Zaopei during the fermentation and distillation process was tested by SPME-GCMS. The result of this study demonstrated that both volatile compounds of Zaopei and thermal reaction during distillation simply determined the unique feature of raw liquor. This study was conducted based on the real products from liquor manufactory, so it is practicable that the method can be used in an industry setting. © 2015 Institute of Food

  11. Minimally processed mixed salad submitted to gamma radiation: effects on bioactive compounds

    Energy Technology Data Exchange (ETDEWEB)

    Hirashima, Fabiana K.; Sabato, Susy F., E-mail: fmayumi@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Lanfer-Marquez, Ursula M., E-mail: lanferum@usp.br [Universidade de Sao Paulo (FCF/USP), Sao Paulo, SP (Brazil). Faculdade de Ciencias Farmaceuticas. Dept. de Alimentos e Nutricao Experimental

    2015-07-01

    High consumption of fruits and vegetables has been associated with a lowered incidence of oxidative stress-related diseases due to the presence of bioactive structures. Minimally processed products are a growing segment in food retail establishments because it is associated with practicality and convenience without significantly altering fresh-like characteristics. Low-dose of gamma radiation in combination with minimal processes has shown to be a promising strategy for extending shelf life and maintaining the organoleptic quality of fruits and vegetables. The objective of this study was to evaluate the levels of phenolic compounds, flavonoids, proanthocyanidins and antioxidant activity by 1,1-diphenyl-2-picrylhydrazyl (DPPH•) free radical scavenging and Oxygen Radical Absorbance Capacity (ORAC) method in minimally processed mixed salad before and after different radiation doses. Samples of minimally processed mixed salad (with green and red cabbage and carrot) were purchased at local supermarket and irradiated with doses of 0.5, 1.0, 2.0 and 3.0 kGy. Phenolic compounds, flavonoids, proanthocyanidins and antioxidant activity by DPPH• and ORAC were analyzed on the same extract prepared with MeOH. The results showed that bioactive compounds levels and antioxidant activity decreased significantly (p<0.05) with an increasing on radiation dose. Gamma-rays may affect these compounds and can cause degradation or oxidation, which can explain the drop on levels. Although the radiation has affected the bioactive contents, the process seems to be interesting to maintaining organoleptic characteristics and provide microbiological security at doses up to 2.0 kGy, according to studies conducted by our research group. (author)

  12. Minimally processed mixed salad submitted to gamma radiation: effects on bioactive compounds

    International Nuclear Information System (INIS)

    Hirashima, Fabiana K.; Sabato, Susy F.; Lanfer-Marquez, Ursula M.

    2015-01-01

    High consumption of fruits and vegetables has been associated with a lowered incidence of oxidative stress-related diseases due to the presence of bioactive structures. Minimally processed products are a growing segment in food retail establishments because it is associated with practicality and convenience without significantly altering fresh-like characteristics. Low-dose of gamma radiation in combination with minimal processes has shown to be a promising strategy for extending shelf life and maintaining the organoleptic quality of fruits and vegetables. The objective of this study was to evaluate the levels of phenolic compounds, flavonoids, proanthocyanidins and antioxidant activity by 1,1-diphenyl-2-picrylhydrazyl (DPPH•) free radical scavenging and Oxygen Radical Absorbance Capacity (ORAC) method in minimally processed mixed salad before and after different radiation doses. Samples of minimally processed mixed salad (with green and red cabbage and carrot) were purchased at local supermarket and irradiated with doses of 0.5, 1.0, 2.0 and 3.0 kGy. Phenolic compounds, flavonoids, proanthocyanidins and antioxidant activity by DPPH• and ORAC were analyzed on the same extract prepared with MeOH. The results showed that bioactive compounds levels and antioxidant activity decreased significantly (p<0.05) with an increasing on radiation dose. Gamma-rays may affect these compounds and can cause degradation or oxidation, which can explain the drop on levels. Although the radiation has affected the bioactive contents, the process seems to be interesting to maintaining organoleptic characteristics and provide microbiological security at doses up to 2.0 kGy, according to studies conducted by our research group. (author)

  13. Bioactive Compound Content and Cytotoxic Effect on Human Cancer Cells of Fresh and Processed Yellow Tomatoes

    Directory of Open Access Journals (Sweden)

    Assunta Raiola

    2015-12-01

    Full Text Available Tomato, as a fresh or processed product, has a high nutritional value due to its content of bioactive components such as phenolic compounds. Few studies describe the effect of processing on antioxidant content and the cancer cell growth inhibition activity. In this study we determined the phenolic and ascorbic acid content of three yellow tomato varieties, before and after thermal processing. Moreover, we determined the antioxidative power and tested the effects of tomato extracts on three human cancer cell lines. We found that the amount of phenolic acids (chlorogenic acid and caffeic acid decreased in all the samples after processing, whereas the flavonoid content increased after the heat treatment in two samples. A cytotoxic effect of tomato extracts was observed only after processing. This result well correlates with the flavonoid content after processing and clearly indicates that processed yellow tomatoes have a high content of bioactive compounds endowed with cytotoxicity towards cancer cells, thus opening the way to obtain tomato-based functional foods.

  14. Chemical and sensory quality of processed carrot puree as influenced by stress-induced phenolic compounds.

    Science.gov (United States)

    Talcott, S T; Howard, L R

    1999-04-01

    Physicochemical analysis of processed strained product was performed on 10 carrot genotypes grown in Texas (TX) and Georgia (GA). Carrots from GA experienced hail damage during growth, resulting in damage to their tops. Measurements included pH, moisture, soluble phenolics, total carotenoids, sugars, organic acids, and isocoumarin (6-MM). Sensory analysis was conducted using a trained panel to evaluate relationships between chemical and sensory attributes of the genotypes and in carrots spiked with increasing levels of 6-MM. Preharvest stress conditions in GA carrots seemed to elicit a phytoalexic response, producing compounds that impacted the perception of bitter and sour flavors. Spiking 6-MM into strained carrots demonstrated the role bitter compounds have in lowering sweetness scores while increasing the perception of sour flavor. Screening fresh carrots for the phytoalexin 6-MM has the potential to significantly improve the sensory quality of processed products.

  15. No fluorinated compounds in the uranium conversion process: risk analysis and proposition of pictograms

    International Nuclear Information System (INIS)

    Jeronimo, Adroaldo Clovis; Oliveira, Wagner dos Santos

    2012-01-01

    The plants comprising the chemical conversion of uranium, which are part of the nuclear fuel cycle, present some risks, among others, because are associated with the non-fluorinated compounds handled in these processes. This study is the analysis of the risks associated with these compounds, i e, the non-fluorinated reactants and products, handled in different chemical processing plants, which include the production of uranium hexafluoride, while emphasizing the responsibilities and actions that fit to the chemical engineer with regard to minimizing risks during the various stages. The work is based on the experience gained during the development and mastery of the technology of production of uranium hexafluoride, the IPEN/ CNEN-SP, during the '80s, with the support of COPESP -Navy of Brazil. (author)

  16. Influence of Technological Processes on Biologically Active Compounds of Produced Grapes Juices

    Czech Academy of Sciences Publication Activity Database

    Tříska, Jan; Balík, J.; Strohalm, J.; Novotná, P.; Vrchotová, Naděžda; Lefnerová, D.; Landfeld, A.; Híc, P.; Tománková, E.; Veverka, J.; Houška, M.

    2016-01-01

    Roč. 9, č. 3 (2016), s. 421-429 ISSN 1935-5130 R&D Projects: GA MŠk(CZ) LO1415; GA MZe QJ1210258; GA MZe QI91B094 Institutional support: RVO:67179843 Keywords : Grapevine juices * Thermomaceration * Biologically active compounds * Antioxidative capacity * Total polyphenols * Antimutagenic activity Subject RIV: GM - Food Processing Impact factor: 2.576, year: 2016

  17. Stochastic Interest Model Based on Compound Poisson Process and Applications in Actuarial Science

    OpenAIRE

    Li, Shilong; Yin, Chuancun; Zhao, Xia; Dai, Hongshuai

    2017-01-01

    Considering stochastic behavior of interest rates in financial market, we construct a new class of interest models based on compound Poisson process. Different from the references, this paper describes the randomness of interest rates by modeling the force of interest with Poisson random jumps directly. To solve the problem in calculation of accumulated interest force function, one important integral technique is employed. And a conception called the critical value is introduced to investigat...

  18. Characterization of chemical compounds for dosimetry of the radiation in industrial processes

    International Nuclear Information System (INIS)

    Galante, Ana Maria Sisti

    1999-01-01

    Different chemical compounds have been studied to optimize dosimetric systems in irradiation processes. In this study 2,3,5 Triphenyl -2H- Tetrazolium Chloride, Brilliant Cresyl Blue, Bromocresol Green and Potassium Nitrate were investigated for their merits or faults, for 60 Co gamma field, in order to verify if can be considered as dosimeters. Fricke solution was used as reference dosimeter to determine absorption dose rates at the gamma facilities.Only Bromocresol Green and Potassium Nitrate are recommended for dosimetry purposes since the main characteristics were achieved. The other two compounds could be used in dosimetry with changes in their formulation. Bromocresol Green and potassium Nitrate are reproducible and radiation sensitive for absorbed doses from 300 Gy to 150 kGy Bromocresol Green was used in liquid form and Potassium Nitrate was prepared in solid pellets form. Spectrophotometry in the visible region was used as the main detection technique, which allows relating optical absorption, before and after irradiation, with the absorbed dose. The maximum absorption wavelength for each compound was observed at 450-460nm for bromocresol Green and 546nm for Potassium Nitrate. Dose calibration curves are linear for both compounds in all dose intervals. When irradiated with accelerated electrons, with energies between o,9 MeV and 1,5MeV, optical absorption intensification, of about 2,6 times, was observed when comparing results for Potassium Nitrate, with those for gamma rays. All the evaluations are presented in this work. (author)

  19. Rubber/clay nanocomposites by combined latex compounding and melt mixing: A masterbatch process

    International Nuclear Information System (INIS)

    Tan, Jinghua; Wang, Xiaoping; Luo, Yuanfang; Jia, Demin

    2012-01-01

    Highlights: → Rubber/Ca-montmorillonite nanocomposites were prepared by the masterbatch process. → Latex compounding method is efficient to improve the Ca-montmorillonite dispersion. → Exfoliated structure was obtained in the masterbatch by latex compounding method. → Intercalated and exfoliated structures were achieved in the vulcanizate. → The properties of vulcanizate are improved by the addition of Ca-montmorillonite. -- Abstract: Rubber/Ca-montmorillonite (Ca-MMT) nanocomposites with well exfoliated Ca-MMT layers were prepared by combination of latex compounding and melt mixing. Firstly, a high Ca-MMT content masterbatch was co-coagulated by natural rubber (NR) latex and modified Ca-MMT aqueous suspension through latex compounding. The masterbatch was added in the system of styrene butadiene rubber (SBR) and epoxidized natural rubber (ENR) by melt mixing subsequently. The X-ray diffraction (XRD) and transmission electronic microscopy (TEM) results showed that intercalated and exfoliated nanocomposites were obtained by the masterbatch technique. The effects of modified Ca-MMT introduction into the rubber matrix, via the masterbatch technique, on the properties of the resulting composites were studied. It was found that the vulcanization was hindered by the incorporation of modified Ca-MMT, while mechanical performances, thermal stability and aging resistance were improved. The increasingly glass transition temperature and the storage modulus with the loading of modified Ca-MMT were measured by dynamic mechanical analysis (DMA).

  20. Solar light-driven photocatalysis using mixed-phase bismuth ferrite (BiFeO3/Bi25FeO40) nanoparticles for remediation of dye-contaminated water: kinetics and comparison with artificial UV and visible light-mediated photocatalysis.

    Science.gov (United States)

    Kalikeri, Shankramma; Shetty Kodialbail, Vidya

    2018-05-01

    Mixed-phase bismuth ferrite (BFO) nanoparticles were prepared by co-precipitation method using potassium hydroxide as the precipitant. X-ray diffractogram (XRD) of the particles showed the formation of mixed-phase BFO nanoparticles containing BiFeO 3 /Bi 25 FeO 40 phases with the crystallite size of 70 nm. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed the formation of quasi-spherical particles. The BFO nanoparticles were uniform sized with narrow size range and with the average hydrodynamic diameter of 76 nm. The band gap energy of 2.2 eV showed its ability to absorb light even in the visible range. Water contaminated with Acid Yellow (AY-17) and Reactive Blue (RB-19) dye was treated by photocatalysis under UV, visible, and solar light irradiation using the BFO nanoparticles. The BFO nanoparticles showed maximum photocatalytical activity under solar light as compared to UV and visible irradiations, and photocatalysis was favored under acidic pH. Complete degradation of AY-17 dyes and around 95% degradation of RB-19 could be achieved under solar light at pH 5. The kinetics of degradation followed the Langmuir-Hinshelhood kinetic model showing that the heterogeneous photocatalysis is adsorption controlled. The findings of this work prove the synthesized BFO nanoparticles as promising photocatalysts for the treatment of dye-contaminated industrial wastewater.

  1. Enhanced magnetic behavior, exchange bias effect, and dielectric property of BiFeO3 incorporated in (BiFeO30.50 (Co0.4Zn0.4Cu0.2 Fe2O40.5 nanocomposite

    Directory of Open Access Journals (Sweden)

    K. Mukhopadhyay

    2014-03-01

    Full Text Available Nanoparticles of BiFeO3 (BFO are incorporated in the nanocomposite of (BiFeO30.50 (Co0.4Zn0.4Cu0.2 Fe2O40.5, (BFO-CZCF and these are prepared by chemical route. The formation of pure crystallographic phase of each component (BFO and CZCF in the nanocomposite of BFO-CZCF has been confirmed by Rietveld analysis of the X-ray diffractograms using FULLPROF program. Morphology, average particle size and its distribution, crystallographic phase etc. are obtained from the high-resolution transmission electron microscopy of BFO-CZCF. Magnetic measurements of BFO-CZCF have been carried out to explore the modulation of magnetic behavior of BFO in BFO-CZCF. Interestingly, magnetization of BFO-CZCF has been drastically enhanced compared to that of the pristine BFO. An exchange bias effect is also observed in the M vs. H loops of BFO-CZCF recorded in field cooled and zero field cooled conditions, which suggest that nanoparticles of BFO (AFM are encapsulated by nanoparticles of CZCF (FM in BFO-CZCF. Thermal variation of dielectric constant of BFO-CZCF is recorded in the range of 300 to 1073 K and a ferroelectric to paraelectric transition is observed at ∼728 K. Enhanced magnetic property of BFO would quite interesting for this important multiferroic.

  2. Optimization of Malaxation Process using Major Aroma Compounds in Virgin Olive Oil

    Directory of Open Access Journals (Sweden)

    Serife Cevik

    Full Text Available ABSTRACT Optimization of major aroma compounds in olive oils produced from fruits at three maturity stages wasstudied. A central composite design was used for the optimization of malaxation conditions of temperature and times, each at five levels with 13 runs including five central points. The responses of interest were trans-2-hexenal and hexanal, which were investigated and their contents were optimized. A full quadratic second order regression model including the linear, quadratic, and two factor interaction effects was proposed to explain the variation in the contents of target compounds depending on the malaxation conditions. Adequacies of models were evaluated by checking regression coefficients for each model. Models were found to work with high success for trans-2-hexenal prediction for oils from fruits at both purple and black stages, whereas the model for hexanalwas only in black stage oil. Their regression coefficients were higher than 0.86. Influences of time and temperature for the malaxation process were found to be significant for the transition of major aroma compounds from the fruit matrix to olive oil. The optimum conditions of temperature and time pairs to maximize trans-2-hexenal and hexanal was found to be 23°C/31 minutes for black olive and to maximize only trans-2-hexenal was also 29°C/41 minutes for purple olive.

  3. Synthesis of heterocyclic compounds through palladium-catalyzed C-H cyclization processes.

    Science.gov (United States)

    Inamoto, Kiyofumi

    2013-01-01

    Herein, we describe our development of synthetic methods for heterocyclic compounds based on the palladium-catalyzed carbon-hydrogen bond (C-H) functionalization/intramolecular carbon-heteroatom (nitrogen or sulfur) bond formation process. By this C-H cyclization method, we efficiently prepared various N-heterocycles, including indazoles, indoles, and 2-quinolinones, as well as S-heterocycles such as benzothiazoles and benzo[b]thiophenes. Yields are typically good to high and good functional-group tolerance is observed for each process, thereby indicating that the method provides a novel, highly applicable synthetic route to the abovementioned biologically important heterocyclic frameworks. As an application of this approach, an auto-tandem-type, one-pot process involving the oxidative Heck reaction and subsequent C-H cyclization using cinnamamides and arylboronic acids as starting materials in the presence of a palladium catalyst was also developed for the rapid construction of the 2-quinolinone nucleus.

  4. Development of a fast and flexible generic process for the reduction of nitro compounds

    DEFF Research Database (Denmark)

    Haas-Santo, K.; Vankayala, B.; Dittmeyer, R.

    slurry catalyst was designed that can be adapted for reduction of a range of nitro compounds. The generic process provides the possibilities of swapping out a reactor or work up technology as required. The equipments of the generic process should be also able to operate at wider range of operational......The hydrogenation of aromatic nitro substrates is a frequently used reaction in the multi-step fabrication of active pharmaceutical ingredients (APIs). Today most pharmaceutical production processes are performed in batch mode. In the frame of the C2-campaign speed is an important factor during...... the production of a multitude of possible API’s. A generic reactor set-up able to be adapted for the transformation of a specific substrate would reduce the development time and thereby the campaign time significantly. In the frame of the EU-project F3-Factory such a flexible and continuous reaction system...

  5. Process for removing halogenated aliphatic and aromatic compounds from petroleum products. [Polychlorinated biphenyls; methylene chloride; perchloroethylene; trichlorofluoroethane; trichloroethylene; chlorobenzene

    Science.gov (United States)

    Googin, J.M.; Napier, J.M.; Travaglini, M.A.

    1982-03-31

    A process for removing halogenated aliphatic and aromatic compounds, e.g., polychlorinated biphenyls, from petroleum products by solvent extraction. The halogenated aliphatic and aromatic compounds are extracted from a petroleum product into a polar solvent by contracting the petroleum product with the polar solvent. The polar solvent is characterized by a high solubility for the extracted halogenated aliphatic and aromatic compounds, a low solubility for the petroleum product and considerable solvent power for polyhydroxy compound. The preferred polar solvent is dimethylformamide. A miscible polyhydroxy compound, such as, water, is added to the polar extraction solvent to increase the polarity of the polar extraction solvent. The halogenated aliphatic and aromatic compounds are extracted from the highly-polarized mixture of polyhydroxy compound and polar extraction solvent into a low polar or nonpolar solvent by contacting the polyhydroxy compound-polar solvent mixture with the low polar or nonpolar solvent. The halogenated aliphatic and aromatic compounds in the low polar or nonpolar solvent by physical means, e.g., vacuum evaporation. The polar and nonpolar solvents are recovered for recycling. The process can easily be designed for continuous operation. Advantages of the process include that the polar solvent and a major portion of the nonpolar solvent can be recycled, the petroleum products are reclaimable and the cost for disposing of waste containing polychlorinated biphenyls is significantly reduced. 2 tables.

  6. Effecting aging time of epoxy molding compound to molding process for integrated circuit packaging

    Science.gov (United States)

    Tachapitunsuk, Jirayu; Ugsornrat, Kessararat; Srisuwitthanon, Warayoot; Thonglor, Panakamon

    2017-09-01

    This research studied about effecting aging time of epoxy molding compound (EMC) that effect to reliability performance of integrated circuit (IC) package in molding process. Molding process is so important of IC packaging process for protecting IC chip (or die) from temperature and humidity environment using encapsulated EMC. For general molding process, EMC are stored in the frozen at 5°C and left at room temperature at 25 °C for aging time on self before molding of die onto lead frame is 24 hours. The aging time effect to reliability performance of IC package due to different temperature and humidity inside the package. In experiment, aging time of EMC were varied from 0 to 24 hours for molding process of SOIC-8L packages. For analysis, these packages were tested by x-ray and scanning acoustic microscope to analyze properties of EMC with an aging time and also analyzed delamination, internal void, and wire sweep inside the packages with different aging time. The results revealed that different aging time of EMC effect to properties and reliability performance of molding process.

  7. Microanalysis on CuInSe2 compound synthesized by mechanochemical processing

    International Nuclear Information System (INIS)

    Wu Sumei; Xue Yuzhi; Zhang Zhihua

    2010-01-01

    CuInSe 2 (CIS) compound has been synthesized by mechanochemical processing (MCP) with different process parameters. The effect of milling time and different molar ratios of Cu:In:Se was investigated. The obtained materials were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) for evaluating their crystal structure, grain size, morphology and composition. Field emission transmission electron microscopy (FETEM) was used to detect the smog particles produced during the milling. The results revealed that the obtained powder was chalcopyrite CuInSe 2 and the particle size was smaller than 5 μm after milling for 60 min. The EDS analysis indicated that the smog was volatile selenium. The composition of the products deviated from those of starting materials after MCP. The mechanism about mechanically induced self-propagating reaction which occurred during milling copper, indium and selenium powders was also discussed.

  8. Selected chemical compounds in firm and mellow persimmon fruit before and after the drying process.

    Science.gov (United States)

    Senica, Mateja; Veberic, Robert; Grabnar, Jana Jurhar; Stampar, Franci; Jakopic, Jerneja

    2016-07-01

    Persimmon is a seasonal fruit and only available in fresh form for a short period of each year. In addition to freezing, drying is the simplest substitute for the fresh fruit and accessible throughout the year. The effect of mellowing and drying was evaluated in 'Tipo' persimmon, an astringent cultivar. 'Tipo' firm fruit contained high levels of tannins (1.1 mg g(-1) DW), which were naturally decreased to 0.2 mg g(-1) DW after mellowing. The drying process greatly impacted the contents of carotenoids, total phenols, individual phenolics, tannins, organic acids, sugars and colour parameters in firm and mellow fruit. The reduction of tannins, phenolic compounds and organic acids were accompanied by the increase of sugars and carotenoids, improving the colour of the analysed samples. These results showed that the drying process improved the quality of persimmon products and extended their shelf life. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  9. Power characteristics of the metal compounds formation process during the friction stir welding

    Directory of Open Access Journals (Sweden)

    Rzaev Radmir

    2017-01-01

    Full Text Available An influence of the power characteristics on the formation process of the uniform metals compound during the welding with friction stirringis being examined in this article.A dependency between the machine-tool engine power input and the instrument tilt during the FSW for the aluminum alloy AD31, copper alloy M1, titanium alloy OT4-1 and steel St-3 low-alloyed has been explored. A question of the stabilization of power consumption process while the establishment of superplastic condition of welded metal during the FSW has also been reviewed. A dependency revealed between the power characteristics, the geometry of the formation, the rotation speeds, the longitudinal displacement of the tool and its dimensions for fixed values of the parameters during the FSW.

  10. Nonthermal food processing alternatives and their effects on taste and flavor compounds of beverages.

    Science.gov (United States)

    Ortega-Rivas, Enrique; Salmerón-Ochoa, Iván

    2014-01-01

    Food drinks are normally processed to increase their shelf-life and facilitate distribution before consumption. Thermal pasteurization is quite efficient in preventing microbial spoilage of many types of beverages, but the applied heat may also cause undesirable biochemical and nutritious changes that may affect sensory attributes of the final product. Alternative methods of pasteurization that do not include direct heat have been investigated in order to obtain products safe for consumption, but with sensory attributes maintained as unchanged as possible. Food scientists interested in nonthermal food preservation technologies have claimed that such methods of preserving foods are equally efficient in microbial inactivation as compared with conventional thermal means of food processing. Researchers in the nonthermal food preservation area also affirm that alternative preservation technologies will not affect, as much as thermal processes, nutritional and sensory attributes of processed foods. This article reviews research in nonthermal food preservation, focusing on effects of processing of food drinks such as fruit juices and dairy products. Analytical techniques used to identify volatile flavor-aroma compounds will be reviewed and comparative effects for both thermal and nonthermal preservation technologies will be discussed.

  11. Pulsed electric field and combination processing of mango nectar: effect on volatile compounds and HMF formation

    Directory of Open Access Journals (Sweden)

    A. S. Bawa

    2015-01-01

    Full Text Available Mango nectar is a commercially familiar and preferred product. The traditional processing of mango nectar has been by thermal processing which resulted in the alteration of the flavour of the product due to the effect of high temperature. The thermal processing of the nectar also resulted in the production of byproducts of non-enzymatic browning such as 5- hydroxy methyl furfural (HMF. These process induced effects, affect both the nutritive and sensory attributes of the fruit product, making it less preferable. With the growing interest and awareness about the benefits of alternative non-thermal technologies, such as pulsed electric field (PEF, the present work was proposed to use PEF to minimize the loss of volatiles and formation of HMF. The study involves thermal (96 ºC for 300 s and 600 s, PEF (24 µs, 120 Hz and 38 kV/cm and combination processing (PEF + Thermal (96 ºC for 90 s of mango nectar. The effect of these treatments on the volatile composition of mango nectar has been analysed using GC-MS technique. The reduction in the volatile compounds was significant (p 0.05 different from unprocessed sample, proving the fresh-like character of the product.

  12. Application of Novel Processing Methods for Greater Retention of Functional Compounds in Fruit-Based Beverages

    Directory of Open Access Journals (Sweden)

    Mariana Morales-de la Peña

    2016-06-01

    Full Text Available Eating habits of western populations are changing due to modern lifestyles. As a result, people are becoming more susceptible to chronic and degenerative diseases. This fact has motivated the food industry to develop functional products that could decrease the incidence of those disorders. It is well known that fruit juices, milk and soymilk possess high concentrations of antioxidant and bioactive substances. Hence, the development of these functional beverages is a potential way to take advantage of their nutritional properties and exotic flavors that could attract the interest of consumers. At the same time, application of the right preservation treatment is of high relevance in order to obtain safe products with convenient shelf life and high concentration of health-related compounds. This fact represents a great challenge that scientists and technologists are currently facing. Today, novel preservation processes such as high hydrostatic pressure (HHP, high intensity pulsed electric fields (HIPEF and ultrasound (US, among others, are being evaluated as an alternative to heat pasteurization, obtaining promising results. Hence, this review gathers the most relevant information about the development of mixed beverages containing fruit juices and milk or soymilk. Furthermore, the advantages and drawbacks of the application of non-thermal treatments for functional beverages’ preservation with high content of bioactive compounds are also mentioned.

  13. TCP (truncated compound Poisson) process for multiplicity distributions in high energy collisions

    International Nuclear Information System (INIS)

    Srivastave, P.P.

    1990-01-01

    On using the Poisson distribution truncated at zero for intermediate cluster decay in a compound Poisson process, the authors obtain TCP distribution which describes quite well the multiplicity distributions in high energy collisions. A detailed comparison is made between TCP and NB for UA5 data. The reduced moments up to the fifth agree very well with the observed ones. The TCP curves are narrower than NB at high multiplicity tail, look narrower at very high energy and develop shoulders and oscillations which become increasingly pronounced as the energy grows. At lower energies the distributions, of the data for fixed intervals of rapidity for UA5 data and for the data (at low energy) for e + e - annihilation and pion-proton, proton-proton and muon-proton scattering. A discussion of compound Poisson distribution, expression of reduced moments and Poisson transforms are also given. The TCP curves and curves of the reduced moments for different values of the parameters are also presented

  14. Removal of enzymatic and fermentation inhibitory compounds from biomass slurries for enhanced biorefinery process efficiencies.

    Science.gov (United States)

    Gurram, Raghu N; Datta, Saurav; Lin, Yupo J; Snyder, Seth W; Menkhaus, Todd J

    2011-09-01

    Within the biorefinery paradigm, many non-monomeric sugar compounds have been shown to be inhibitory to enzymes and microbial organisms that are used for hydrolysis and fermentation. Here, two novel separation technologies, polyelectrolyte polymer adsorption and resin-wafer electrodeionization (RW-EDI), have been evaluated to detoxify a dilute acid pretreated biomass slurry. Results showed that detoxification of a dilute acid pretreated ponderosa pine slurry by sequential polyelectrolyte and RW-EDI treatments was very promising, with significant removal of acetic acid, 5-hydroxymethyl furfural, and furfural (up to 77%, 60%, and 74% removed, respectively) along with >97% removal of sulfuric acid. Removal of these compounds increased the cellulose conversion to 94% and elevated the hydrolysis rate to 0.69 g glucose/L/h. When using Saccharomyces cerevisiae D(5)A for fermentation of detoxified slurry, the process achieved 99% of the maximum theoretical ethanol yield and an ethanol production rate nearly five-times faster than untreated slurry. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. High field magnetization process of (Sm, Nd)2Fe17Ny compounds

    International Nuclear Information System (INIS)

    Yu, M.J.; Tang, N.; Liu, Y.L.; Tegus, O.; Lu, Y.; Kuang, J.P.; Yang, F.M.; Li, X.; Zhou, G.F.; Boer, F.R. de

    1992-01-01

    The crystal structure and high-field magnetization process of (Sm 1-x Nd x ) 2 Fe 17 N y compounds (x = 0.0, 0.1, ..., 1.0, 2 1-x Nd x ) 2 Fe 17 N y compounds were found to crystallize in the rhombohedral Th 2 Zn 17 structure. As x increases, the Curie temperature decreases. The anisotropy fields and easy magnetization direction were investigated from 1.5 K to room temperature by means of high-field magnetization measurements and AC-susceptibility measurements, combined with X-ray diffraction on random and magnetically aligned powder samples. The anisotropy field decreases with increasing x and approaches a minimum value at about x = 0.6, then increases again. A tentative spin phase diagram for the (Sm 1-x Nd x ) 2 Fe 17 N y series is presented. At room temperature, the easy magnetization direction remains along the c-axis up to x = 0.6. (orig.)

  16. Effects of extrusion, infrared and microwave processing on Maillard reaction products and phenolic compounds in soybean.

    Science.gov (United States)

    Zilić, Slađana; Mogol, Burçe Ataç; Akıllıoğlu, Gül; Serpen, Arda; Delić, Nenad; Gökmen, Vural

    2014-01-15

    The Maillard reaction indicators furosine, hydroxymethylfurfural (HMF), acrylamide and color were determined to evaluate heat effects induced during extrusion, infrared and microwave heating of soybean. In addition, the present paper aimed to study changes in the phenolic compounds, as well as in the overall antioxidant properties of different soybean products in relation to heating at 45-140 °C during the processes. Soybean proteins were highly sensible to Maillard reaction and furosine was rapidly formed under slight heating conditions during extrusion and infrared heating. Microwave heating at lower temperatures for a longer time yielded lower acrylamide levels in the final soybean products, as a result of its partial degradation. However, during infrared heating, acrylamide formation greatly increased with decreasing moisture content. After a short time of extrusion and infrared heating at 140 °C and microwave heating at 135 °C for 5 min, concentrations of HMF increased to 11.34, 26.21 and 34.97 µg g(-1), respectively. The heating conditions caused formation of acrylamide, HMF and furosine in high concentration. The results indicate that the complex structure of soybeans provides protection of phenolic compounds from thermal degradation, and that Maillard reaction products improved the antioxidant properties of heat-treated soybean. © 2013 Society of Chemical Industry.

  17. Identification of characteristic aroma compounds in raw and thermally processed African giant snail (Achatina fulica).

    Science.gov (United States)

    Lasekan, Ola; Muniady, Megala; Lin, Mee; Dabaj, Fatma

    2018-04-24

    Food flavor appreciation is one of the first signals along with food appearance and texture encountered by consumers during eating of food. Also, it is well known that flavor can strongly influence consumer's acceptability judgment. The increase in the consumption of snail meat across the world calls for the need to research into the aroma compounds responsible for the distinctive aroma notes of processed snail meat. The odorants responsible for the unique aroma notes in thermally processed giant African snail meats were evaluated by means of aroma extract dilution analysis (AEDA), gas chromatography-olfactometry (GC-O) and odor activity values (OAVs) respectively. Results revealed significant differences in the aroma profiles of the raw and thermally processed snail meats. Whilst the aroma profile of the raw snail meat was dominated with the floral-like β-ionone and β-iso-methyl ionone, sweaty/cheesy-like butanoic acid, and the mushroom-like 1-octen-3-one, the boiled and fried samples were dominated with the thermally generated odorants like 2-methylpyrazine, 2,5-dimethylpyrazine, 2-acetylthiazole and 2-acetylpyridine. Finally, results have shown that sotolon, 2-acetyl-1-pyrroline, 2-furanmethanethiol, 2-methylbutanal, 1-octen-3-one, octanal, furanone, 2-methoxyphenol, 2-acetylpyridine, 2-acetylthiazole, and 2-methylpyrazine contributed to the overall aroma of the thermally processed snail meat.

  18. Compound Poisson Processes and Clustered Damage of Radiation Induced DNA Double Strand Breaks

    International Nuclear Information System (INIS)

    Gudowska-Nowak, E.; Ritter, S.; Taucher-Scholz, G.; Kraft, G.

    2000-01-01

    Recent experimental data have demonstrated that DNA damage induced by densely ionizing radiation in mammalian cells is distributed along the DNA molecule in the form of clusters. The principal constituent of DNA damage are double-strand breaks (DSB) which are formed when the breaks occur in both DNA strands and are directly opposite or separated by only a few base pairs. DSBs are believed to be most important lesions produced in chromosomes by radiation; interaction between DSBs can lead to cell killing, mutation or carcinogenesis. The paper discusses a model of clustered DSB formation viewed in terms of compound Poisson process along with the predictive essay of the formalism in application to experimental data. (author)

  19. Oxidation of organic compounds in wastewater from the humid processing of coffee berries

    International Nuclear Information System (INIS)

    Goncalves, Maraisa; Guerreiro, Mario Cesar; Oliveira, Luiz Carlos Alves; Rocha, Cristian Luciana da

    2008-01-01

    Materials based on pure iron oxide and impregnated with niobia (Nb 2 O 5 ) were prepared. Their catalytic activities were tested on the oxidation of compounds present in the wastewater from the processing of coffee berries. Particularly caffeine and catechol were tested. The oxidation reactions were carried out with the following systems: UV/H 2 O 2 ; photo-Fenton and heterogeneous Fenton. All materials were characterized with X-ray diffraction, Moessbauer and infrared spectroscopy. Iron was mainly in the forms of goethite and maghemite. The oxidation kinetics were monitored by UV-vis and the oxidation products were monitored by mass spectrometry. The photo-Fenton reaction presented highest oxidation efficiency, removing 98% of all caffeine and catechol contents. (author)

  20. Cooking processes increase bioactive compounds in organic and conventional green beans.

    Science.gov (United States)

    Lima, Giuseppina Pace Pereira; Costa, Sergio Marques; Monaco, Kamila de Almeida; Uliana, Maira Rodrigues; Fernandez, Roberto Morato; Correa, Camila Renata; Vianello, Fabio; Cisneros-Zevallos, Luis; Minatel, Igor Otavio

    2017-12-01

    The influence of cooking methods on chlorophyl, carotenoids, polyamines, polyphenols contents and antioxidant capacity were analyzed in organic and conventional green beans. The initial raw material had a higher content of chlorophyl and total phenolics in conventional green beans, whereas organic cultive favored flavonoid content and antioxidant capacity. Polyamines and carotenoids were similar for the two crop systems. After the cooking process, carotenoids (β-carotene, lutein and zeaxanthin) increased. Microwave heating favored the enhancement of some polar compounds, whereas pressure cooking favored carotenoids. When we used the estimation of the radical scavenging activity by electron spin resonance (ESR) spectroscopy, a reduction of the DPPH radical signal in the presence of green bean extracts was observed, regardless of the mode of cultivation. The highest reduction of the ESR signal ocurred for microwave cooking in organic and conventional green beans, indicating a higher availability of antioxidants with this type of heat treatment.

  1. Stochastic Interest Model Based on Compound Poisson Process and Applications in Actuarial Science

    Directory of Open Access Journals (Sweden)

    Shilong Li

    2017-01-01

    Full Text Available Considering stochastic behavior of interest rates in financial market, we construct a new class of interest models based on compound Poisson process. Different from the references, this paper describes the randomness of interest rates by modeling the force of interest with Poisson random jumps directly. To solve the problem in calculation of accumulated interest force function, one important integral technique is employed. And a conception called the critical value is introduced to investigate the validity condition of this new model. We also discuss actuarial present values of several life annuities under this new interest model. Simulations are done to illustrate the theoretical results and the effect of parameters in interest model on actuarial present values is also analyzed.

  2. A process-based emission model of volatile organic compounds from silage sources on farms

    DEFF Research Database (Denmark)

    Bonifacio, H. F.; Rotz, C. A.; Hafner, S. D.

    2017-01-01

    Silage on dairy farms can emit large amounts of volatile organic compounds (VOCs), a precursor in the formation of tropospheric ozone. Because of the challenges associated with direct measurements, process-based modeling is another approach for estimating emissions of air pollutants from sources...... was evaluated using ethanol and methanol emissions measured from conventional silage piles (CSP), silage bags (SB), total mixed rations (TMR), and loose corn silage (LCS) at a commercial dairy farm in central California. With transport coefficients for ethanol refined using experimental data from our previous......% if feeds were delivered as four feedings per day rather than as one. Reducing the exposed face of storage can also be useful. Simulated use of silage bags resulted in 90% and 18% reductions in emissions from the storage face and whole farm, respectively....

  3. Evaluation of organic and inorganic compounds levels of red wines processed from Pinot Noir grapes

    Directory of Open Access Journals (Sweden)

    Heli Sirén

    2015-03-01

    The wine products showed different profiles of carbohydrates, organic acids, phenolic compounds, and minerals. Especially, saccharose (max. 0.21 g/L, rhamnose (max. 0.45 g/L, fructose (max. 1.9 g/L, and phosphate (max 1.4 g/L quantities were extremely high in some wines. The results also showed that yeast fermentation in winemaking agitated high production of lactic (max 5.7 g/L and tartaric (max 1.7 g/L acids. The red wines processed by cold maceration and natural fermentation gave similar profiles. Only one of the Pinot Noir wines entirely differentiated from the others with comparison of carbohydrates and organic acids.

  4. Characterization of methyl ester compound of biodiesel from industrial liquid waste of crude palm oil processing

    Directory of Open Access Journals (Sweden)

    Maulidiyah

    2017-06-01

    Full Text Available The second generation of Bioenergy: a study of CPO liquid waste-based biodiesel production technology has been conducted. The aims of this study were to obtain biodiesel from Industrial liquid waste of CPO processing and to identify the kind of methyl-ester compound of the biodiesel. The production of biodiesel was applied in two steps of reactions; esterification reaction using H2SO4 and transesterification using CaO catalyst at 60 °C for 2 h. GC-MS analysis result showed that methyl ester from liquid waste of CPO contains methyl hexadecanoate 12.87%, methyl 9-octadecanoate 19.98%, methyl octadecanoate 5.71%, and methyl 8,11-octadecadienoate 10.22%.

  5. Cloud processing of organic compounds: Secondary organic aerosol and nitrosamine formation

    Science.gov (United States)

    Hutchings, James W., III

    Cloud processing of atmospheric organic compounds has been investigated through field studies, laboratory experiments, and numerical modeling. Observational cloud chemistry studies were performed in northern Arizona and fog studies in central Pennsylvania. At both locations, the cloud and fogs showed low acidity due to neutralization by soil dust components (Arizona) and ammonia (Pennsylvania). The field observations showed substantial concentrations (20-5500 ng•L -1) of volatile organic compounds (VOC) in the cloud droplets. The potential generation of secondary organic aerosol mass through the processing of these anthropogenic VOCs was investigated through laboratory and modeling studies. Under simulated atmospheric conditions, in idealized solutions, benzene, toluene, ethylbenzene, and xylene (BTEX) degraded quickly in the aqueous phase with half lives of approximately three hours. The degradation process yielded less volatile products which would contribute to new aerosol mass upon cloud evaporation. However, when realistic cloud solutions containing natural organic matter were used in the experiments, the reaction kinetics decreased with increasing organic carbon content, resulting in half lives of approximately 7 hours. The secondary organic aerosol (SUA) mass formation potential of cloud processing of BTEX was evaluated. SOA mass formation by cloud processing of BTEX, while strongly dependent on the atmospheric conditions, could contribute up to 9% of the ambient atmospheric aerosol mass, although typically ˜1% appears realistic. Field observations also showed the occurrence of N-nitrosodimethylamine (NDMA), a potent carcinogen, in fogs and clouds (100-340 ng•L -1). Laboratory studies were conducted to investigate the formation of NDMA from nitrous acid and dimethylamine in the homogeneous aqueous phase within cloud droplets. While NDMA was produced in the cloud droplets, the low yields (NDMA with partitioning to droplet must be the source of aqueous

  6. Synthesis, Processing, and Thermoelectric Properties of Germanium-Antimony-Tellurium Based Compounds and Alloys

    Science.gov (United States)

    Williams, Jared Brett

    Society has become increasingly more aware of the negative impacts which nonrenewable energy sources have on the environment, and therefore the search for new and more efficient means of energy production has become an important research endeavor. Thermoelectric modules possess the unique ability to convert wasted heat into useful electrical energy via solid state processes, which could vastly improve the efficiency of a number of applications. The materials which accomplish this are typically comprised of semiconductors which exhibit high electrical conductivity, Seebeck coefficient, and thermal resistivity. Together these properties give us a gauge for the overall efficiency of the thermal to electrical energy conversion. Phase change materials are a class of materials primarily used for optical data storage in CDs, DVDs, and Blu-Ray discs. Today's state of the art phase change materials are based on alloys of GeTe and Sb2Te3. These materials have also been found to exhibit high thermoelectric efficiencies. These high efficiencies stem from their complex crystal structure and degenerate semiconducting nature. The purpose of this work was to study and engineer the thermoelectric properties of various alloys and compounds which belong to this family of materials. Specifically studied were the compounds Ge4SbTe5 and Ge17Sb2Te20. In each case various synthesis and processing strategies were implemented to increase the thermoelectric performance and better understand the fundamental electrical and thermal properties. Finally various proposals for future work on these materials are presented, all of which are based on the findings described herein.

  7. Compound-specific isotopic analyses: a novel tool for reconstruction of ancient biogeochemical processes

    Science.gov (United States)

    Hayes, J. M.; Freeman, K. H.; Popp, B. N.; Hoham, C. H.

    1990-01-01

    Patterns of isotopic fractionation in biogeochemical processes are reviewed and it is suggested that isotopic fractionations will be small when substrates are large. If so, isotopic compositions of biomarkers will reflect those of their biosynthetic precursors. This prediction is tested by consideration of results of analyses of geoporphyrins and geolipids from the Greenhorn Formation (Cretaceous, Western Interior Seaway of North America) and the Messel Shale (Eocene, lacustrine, southern Germany). It is shown (i) that isotopic compositions of porphyrins that are related to a common source, but which have been altered structurally, cluster tightly and (ii) that isotopic differences between geolipids and porphyrins related to a common source are equal to those observed in modern biosynthetic products. Both of these observations are consistent with preservation of biologically controlled isotopic compositions during diagenesis. Isotopic compositions of individual compounds can thus be interpreted in terms of biogeochemical processes in ancient depositional environments. In the Cretaceous samples, isotopic compositions of n-alkanes are covariant with those of total organic carbon, while delta values for pristane and phytane are covariant with those of porphyrins. In this unit representing an open marine environment, the preserved acyclic polyisoprenoids apparently derive mainly from primary material, while the extractable, n-alkanes derive mainly from lower levels of the food chain. In the Messel Shale, isotopic compositions of individual biomarkers range from -20.9 to -73.4% vs PDB. Isotopic compositions of specific compounds can be interpreted in terms of origin from methylotrophic, chemautotrophic, and chemolithotrophic microorganisms as well as from primary producers that lived in the water column and sediments of this ancient lake.

  8. Modifications in the chemical compounds and sensorial attributes of Engraulis anchoita fillet during marinating process

    Directory of Open Access Journals (Sweden)

    Maria Isabel Yeannes

    2008-12-01

    Full Text Available Marinated fish are fish products preserved by the combined action of salt and organic acids. The objective of this work was to analyze the variations in the chemical compounds of anchovy fillets that give them sensorial characteristics during the marinating process of Engraulis anchoita. The protein content decreased slightly and the TVB-N level decreased significantly in both the brining and marinating stages. In the marinating stage an increase in the total free aminoacids was observed. The NBV level in the brining and marinating solutions increased during these stages due to the solubilization of the non-protein nitrogenous compounds and the degradation of some protein compounds.The decrease of the contents of protein and TVB-N, and the increase of the acidity and the free aminoacids content during the marinating process give the marinated fillets the characteristic texture and aroma.Peixes marinados são produtos obtidos pela ação combinada de sal e ácidos orgânicos. O presente estudo teve como objetivo avaliar as alterações químicas e sensoriais em filés de anchoita (Engraulis anchoita durante o processo de marinado. O conteúdo de proteína apresentou decréscimo significativo durante a salga. O teor de Bases Voláteis Totais-N-BVT, apresentou uma diminuição considerável durante a salga e marinacão. Na fase de marinado, foi observado um aumento em aminoácidos livres totais. Foi constatada a presença de N-BVT na salmoura e na solução oriunda do processo de obtenção de marinado, devido à solubilização de nitrogênio não protéico, que podem ter sido acrescidos de alguns compostos de degradação protéica. A redução do conteúdo de proteína e N-BVT e o aumento de acidez e de aminoácidos livres gerados durante ou processo de elaboração do marinado fazem com que os filés marinados adquiram textura e aroma característicos.

  9. Speckle reduction process based on digital filtering and wavelet compounding in optical coherence tomography for dermatology

    Science.gov (United States)

    Gómez Valverde, Juan J.; Ortuño, Juan E.; Guerra, Pedro; Hermann, Boris; Zabihian, Behrooz; Rubio-Guivernau, José L.; Santos, Andrés.; Drexler, Wolfgang; Ledesma-Carbayo, Maria J.

    2015-07-01

    Optical Coherence Tomography (OCT) has shown a great potential as a complementary imaging tool in the diagnosis of skin diseases. Speckle noise is the most prominent artifact present in OCT images and could limit the interpretation and detection capabilities. In this work we propose a new speckle reduction process and compare it with various denoising filters with high edge-preserving potential, using several sets of dermatological OCT B-scans. To validate the performance we used a custom-designed spectral domain OCT and two different data set groups. The first group consisted in five datasets of a single B-scan captured N times (with N<20), the second were five 3D volumes of 25 Bscans. As quality metrics we used signal to noise (SNR), contrast to noise (CNR) and equivalent number of looks (ENL) ratios. Our results show that a process based on a combination of a 2D enhanced sigma digital filter and a wavelet compounding method achieves the best results in terms of the improvement of the quality metrics. In the first group of individual B-scans we achieved improvements in SNR, CNR and ENL of 16.87 dB, 2.19 and 328 respectively; for the 3D volume datasets the improvements were 15.65 dB, 3.44 and 1148. Our results suggest that the proposed enhancement process may significantly reduce speckle, increasing SNR, CNR and ENL and reducing the number of extra acquisitions of the same frame.

  10. Simulation of Injection Molding Process Including Mold Filling and Compound Curing

    Directory of Open Access Journals (Sweden)

    Mohamad Reza Erfanian

    2012-12-01

    Full Text Available The present work reports and discusses the results of a 3D simulation of the injection molding process of a rubber compound that includes the mold flling stage and  material curing, using the computer code is developed in “UDF” part of the Fluent 6.3 CAE software. The data obtained from a rheometer (MDR 2000 is used to characterize the rubber material in order to fnd the cure model parameters which exist in curing model. Because of non-newtonian behavior of rubber, in this work the non-newtonian model for viscosity was used and viscosity parameters were computed by mean of viscometry test by RPA. After calculation of the physical and curing properties, vulcanization process was simulated for a complex rubber article with non-uniform thickness by solving the continuity, momentum, energy and curing process equations. Predicted flling and curing time in a complex and 3D rubber part is compared with experimentally measured data which confrmed  the accuracy and applicability of the method.

  11. Effects of high hydrostatic pressure and thermal processing on bioactive compounds, antioxidant activity, and volatile profile of mulberry juice.

    Science.gov (United States)

    Wang, Fan; Du, Bao-Lei; Cui, Zheng-Wei; Xu, Li-Ping; Li, Chun-Yang

    2017-03-01

    The aim of this study was to investigate the effects of high hydrostatic pressure and thermal processing on microbiological quality, bioactive compounds, antioxidant activity, and volatile profile of mulberry juice. High hydrostatic pressure processing at 500 MPa for 10 min reduced the total viable count from 4.38 log cfu/ml to nondetectable level and completely inactivated yeasts and molds in raw mulberry juice, ensuring the microbiological safety as thermal processing at 85 ℃ for 15 min. High hydrostatic pressure processing maintained significantly (p hydrostatic pressure processing enhanced the volatile compound concentrations of mulberry juice while thermal processing reduced them in comparison with the control. These results suggested that high hydrostatic pressure processing could be an alternative to conventional thermal processing for production of high-quality mulberry juice.

  12. Effect of alcoholic fermentation in the content of phenolic compounds in cider processing

    Directory of Open Access Journals (Sweden)

    Alessandro Nogueira

    2008-10-01

    Full Text Available The objective of this work was to study the effect of alcoholic fermentation on the content of phenol compounds of five cider apple varieties. The initial content in the apple juice samples, as determined by HPLC, varied from 188.4 to 2776.17 m mg.L-1. In three of them (DC, PJ, GU, the total phenol compounds remained unaffected by fermentation. However, in two (DM, KE, the final values were lower (55 and 313 mg.L-1. In these apple cider, the values of caffeic acid increased from 6.6 mg.L-1 to 41.8 mg.L-1. The catechin content increased during the process, approximately 13 mg.L-1 independent of the variety. The other phenols class did not present any modifications due to the alcoholic fermentation, maintaining the phenolic compounds of original clarified apple juice in the cider.O objetivo deste trabalho foi estudar o efeito da fermentação alcoólica no teor de compostos fenólicos de cinco mostos de maçãs industriais. Os compostos fenólicos foram analisados por HPLC. Os mostos apresentaram fenóis totais entre 188,4 a 2776,17 mg.L-1. Os teores de fenóis durante a fermentação permaneceram os mesmos para as variedades DC, PJ e GU, entretanto, em DM e KE foi observada uma diminuição dos teores de fenóis (55 e 313 mg.L-1, respectivamente. Em KE o teor do ácido caféico aumentou de 6,6 mg.L-1 para 41,8 mg.L-1. O teor de catequinas aumentou cerca de 13 mg.L-1 durante o processo, independente da variedade. As outras classes de fenóis não apresentaram modificações com a fermentação alcoólica, permanecendo na sidra os compostos fenólicos do suco de maçã clarificado.

  13. A Multi-Objective Compounded Local Mobile Cloud Architecture Using Priority Queues to Process Multiple Jobs.

    Science.gov (United States)

    Wei, Xiaohui; Sun, Bingyi; Cui, Jiaxu; Xu, Gaochao

    2016-01-01

    As a result of the greatly increased use of mobile devices, the disadvantages of portable devices have gradually begun to emerge. To solve these problems, the use of mobile cloud computing assisted by cloud data centers has been proposed. However, cloud data centers are always very far from the mobile requesters. In this paper, we propose an improved multi-objective local mobile cloud model: Compounded Local Mobile Cloud Architecture with Dynamic Priority Queues (LMCpri). This new architecture could briefly store jobs that arrive simultaneously at the cloudlet in different priority positions according to the result of auction processing, and then execute partitioning tasks on capable helpers. In the Scheduling Module, NSGA-II is employed as the scheduling algorithm to shorten processing time and decrease requester cost relative to PSO and sequential scheduling. The simulation results show that the number of iteration times that is defined to 30 is the best choice of the system. In addition, comparing with LMCque, LMCpri is able to effectively accommodate a requester who would like his job to be executed in advance and shorten execution time. Finally, we make a comparing experiment between LMCpri and cloud assisting architecture, and the results reveal that LMCpri presents a better performance advantage than cloud assisting architecture.

  14. A Multi-Objective Compounded Local Mobile Cloud Architecture Using Priority Queues to Process Multiple Jobs.

    Directory of Open Access Journals (Sweden)

    Xiaohui Wei

    Full Text Available As a result of the greatly increased use of mobile devices, the disadvantages of portable devices have gradually begun to emerge. To solve these problems, the use of mobile cloud computing assisted by cloud data centers has been proposed. However, cloud data centers are always very far from the mobile requesters. In this paper, we propose an improved multi-objective local mobile cloud model: Compounded Local Mobile Cloud Architecture with Dynamic Priority Queues (LMCpri. This new architecture could briefly store jobs that arrive simultaneously at the cloudlet in different priority positions according to the result of auction processing, and then execute partitioning tasks on capable helpers. In the Scheduling Module, NSGA-II is employed as the scheduling algorithm to shorten processing time and decrease requester cost relative to PSO and sequential scheduling. The simulation results show that the number of iteration times that is defined to 30 is the best choice of the system. In addition, comparing with LMCque, LMCpri is able to effectively accommodate a requester who would like his job to be executed in advance and shorten execution time. Finally, we make a comparing experiment between LMCpri and cloud assisting architecture, and the results reveal that LMCpri presents a better performance advantage than cloud assisting architecture.

  15. [Emission characteristics and safety evaluation of volatile organic compounds in manufacturing processes of automotive coatings].

    Science.gov (United States)

    Zeng, Pei-Yuan; Li, Jian-Jun; Liao, Dong-Qi; Tu, Xiang; Xu, Mei-Ying; Sun, Guo-Ping

    2013-12-01

    Emission characteristics of volatile organic compounds (VOCs) were investigated in an automotive coating manufacturing enterprise. Air samples were taken from eight different manufacturing areas in three workshops, and the species of VOCs and their concentrations were measured by gas chromatography-mass spectrometry (GC-MS). Safety evaluation was also conducted by comparing the concentration of VOCs with the permissible concentration-short term exposure limit (PC-STEL) regulated by the Ministry of Health. The results showed that fifteen VOCs were detected in the indoor air of the automotive coatings workshop, including benzene, toluene, ethylbenzene, xylene, ethyl acetate, butyl acetate, methyl isobutyl ketone, propylene glycol monomethyl ether acetate, trimethylbenzene and ethylene glycol monobutyl ether, Their concentrations widely ranged from 0.51 to 593.14 mg x m(-3). The concentrations of TVOCs were significantly different among different manufacturing processes. Even in the same manufacturing process, the concentrations of each component measured at different times were also greatly different. The predominant VOCs of indoor air in the workshop were identified to be ethylbenzene and butyl acetate. The concentrations of most VOCs exceeded the occupational exposure limits, so the corresponding control measures should be taken to protect the health of the workers.

  16. Moessbauer Study of the Ball Milling Disordering Process of FeAl Intermetallic Compounds

    International Nuclear Information System (INIS)

    Oleszak, Dariusz; Bruna, Pere; Crespo, Daniel; Pradell, Trinitat

    2005-01-01

    Structural changes during ball milling of ordered Fe50Al50 intermetallic compounds were studied. X-Ray diffraction allowed the computation of a Long Range Order parameter (LRO) which dropped to zero after a short milling time. The initial B2 ordered structure gradually transforms into a disordered BCC structure, with a final crystallite size of about 25 nm. Moessbauer spectroscopy was used for obtaining a Chemical Short Range Order parameter (CSRO). Using a semiempirical n-body noncentral potential a model of the partially disordered B2 structure was built allowing computing the distribution of Quadrupole Splitting during the disordering process. Comparison between experimental and simulated Moessbauer spectra shows a maximum of disorder in the system for 5h milling, related to the highest value of the lattice spacing and the broader quadrupole hyperfine distribution. However, after milling for times longer than 5h, there is a change on the behavior of the experimental data that cannot be explained by the simple disordering process

  17. Chemomics-based marker compounds mining and mimetic processing for exploring chemical mechanisms in traditional processing of herbal medicines, a continuous study on Rehmanniae Radix.

    Science.gov (United States)

    Zhou, Li; Xu, Jin-Di; Zhou, Shan-Shan; Shen, Hong; Mao, Qian; Kong, Ming; Zou, Ye-Ting; Xu, Ya-Yun; Xu, Jun; Li, Song-Lin

    2017-12-29

    Exploring processing chemistry, in particular the chemical transformation mechanisms involved, is a key step to elucidate the scientific basis in traditional processing of herbal medicines. Previously, taking Rehmanniae Radix (RR) as a case study, the holistic chemome (secondary metabolome and glycome) difference between raw and processed RR was revealed by integrating hyphenated chromatographic techniques-based targeted glycomics and untargeted metabolomics. Nevertheless, the complex chemical transformation mechanisms underpinning the holistic chemome variation in RR processing remain to be extensively clarified. As a continuous study, here a novel strategy by combining chemomics-based marker compounds mining and mimetic processing is proposed for further exploring the chemical mechanisms involved in herbal processing. First, the differential marker compounds between raw and processed herbs were rapidly discovered by untargeted chemomics-based mining approach through multivariate statistical analysis of the chemome data obtained by integrated metabolomics and glycomics analysis. Second, the marker compounds were mimetically processed under the simulated physicochemical conditions as in the herb processing, and the final reaction products were chemically characterized by targeted chemomics-based mining approach. Third, the main chemical transformation mechanisms involved were clarified by linking up the original marker compounds and their mimetic processing products. Using this strategy, a set of differential marker compounds including saccharides, glycosides and furfurals in raw and processed RR was rapidly found, and the major chemical mechanisms involved in RR processing were elucidated as stepwise transformations of saccharides (polysaccharides, oligosaccharides and monosaccharides) and glycosides (iridoid glycosides and phenethylalcohol glycosides) into furfurals (glycosylated/non-glycosylated hydroxymethylfurfurals) by deglycosylation and/or dehydration. The

  18. Partition behavior of virgin olive oil phenolic compounds in oil-brine mixtures during thermal processing for fish canning.

    Science.gov (United States)

    Sacchi, Raffaele; Paduano, Antonello; Fiore, Francesca; Della Medaglia, Dorotea; Ambrosino, Maria Luisa; Medina, Isabel

    2002-05-08

    The chemical modifications and partitioning toward the brine phase (5% salt) of major phenol compounds of extra virgin olive oil (EVOO) were studied in a model system formed by sealed cans filled with oil-brine mixtures (5:1, v/v) simulating canned-in-oil food systems. Filled cans were processed in an industrial plant using two sterilization conditions commonly used during fish canning. The partitioning of phenolic compounds toward brine induced by thermal processing was studied by reversed-phase high-performance liquid chromatographic analysis of the phenol fraction extracted from oils and brine. Hydroxytyrosol (1), tyrosol (2), and the complex phenolic compounds containing 1 and 2 (i.e., the dialdehydic form of decarboxymethyl oleuropein aglycon 3, the dialdehydic form of decarboxymethyl ligstroside aglycon 4, and the oleuropein aglycon 6) decreased in the oily phase after sterilization with a marked partitioning toward the brine phase. The increase of the total amount of 1 and 2 after processing, as well as the presence of elenolic acid 7 released in brine, revealed the hydrolysis of the ester bond of hydrolyzable phenolic compounds 3, 4, and 6 during thermal processing. Both phenomena (partitioning toward the water phase and hydrolysis) contribute to explain the loss of phenolic compounds exhibited by EVOO used as filling medium in canned foods, as well as the protection of n-3 polyunsaturated fatty acids in canned-in-EVOO fish products.

  19. The compositional study of nitrogen and oxygen compounds in products of heavy oil primary and secondary upgrading processes. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Chmielowiec, J.

    1986-02-01

    The primary objective was to characterize nitrogen and oxygen compound types in the upgraded products derived from Athabasca bitumen. Nitrogen compounds, depending on their nature and concentrations, in charge stocks to catalytic processess (hydro-processes and reforming) can severely limit or poison the catalyst activity. Oxygen compounds are corrosive (especially naphthenic acids) and can promote gum formation as part of the deterioration of the hydrocarbons in the petroleum product. A secondary objective was to evaluate the advantages and limitations of in-house mass spectrometry and infrared spectroscopy methods for analyzing specific classes of polar compounds in naphthas, middle distillates, and gas oils. An analytical procedure that was based on the discrimination of polar compound classes using liquid chromatography followed by mass spectrometric analysis was tested. The chemical intelligence on the fractions obtained from Athabasca bitumen and its upgrading products has been advanced by determining structural characteristics of the nitrogen and oxygen components. This report describes the determination of the distributions of nitrogen and oxygen compounds in samples from various process streams. This procedure is capable of providing information useful for evaluating hydrodenitrogenation and hydrodeoxygenation reactions.

  20. Destructive hydrogenation; dehydrogenation and dehydrogenation processes; purifying oils; polynuclear organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    1934-02-08

    Unitary organic compounds containing four or more nuclei are recovered from the high boiling fractions of destructive hydrogenation products of bituminous, resinous, or ligneous materials. Cooling, precipitation, crystallization, selective dissolution and distillation are some of the techniques discussed. These techniques may also be applied to the recovery of polynuclear compounds.

  1. Reading Polymorphemic Dutch Compounds: Toward a Multiple Route Model of Lexical Processing

    Science.gov (United States)

    Kuperman, Victor; Schreuder, Robert; Bertram, Raymond; Baayen, R. Harald

    2009-01-01

    This article reports an eye-tracking experiment with 2,500 polymorphemic Dutch compounds presented in isolation for visual lexical decision while readers' eye movements were registered. The authors found evidence that both full forms of compounds ("dishwasher") and their constituent morphemes (e.g., "dish," "washer," "er") and morphological…

  2. Use of Electrohydrodynamic Processing for Encapsulation of Sensitive Bioactive Compounds and Applications in Food

    DEFF Research Database (Denmark)

    Jacobsen, Charlotte; García Moreno, Pedro Jesús; Mendes, Ana Carina Loureiro

    2018-01-01

    or in the gastrointestinal tract. For that purpose, efficient encapsulation of the compounds may be required. Spray drying is one of the most commonly used encapsulation techniques in the food industry, but it uses high temperature, which can lead to decomposition of the bioactive compounds. Recently, alternative...

  3. Bioactive compounds and quality parameters of avocado oil obtained by different processes.

    Science.gov (United States)

    Krumreich, Fernanda D; Borges, Caroline D; Mendonça, Carla Rosane B; Jansen-Alves, Cristina; Zambiazi, Rui C

    2018-08-15

    The objective of this study was to evaluate the quality of avocado oil whose pulp was processed through different drying and oil extraction methods. The physicochemical characteristics of avocados cv. Breda were determined after drying the pulp in an oven under ventilation (40 °C and 60 °C) and vacuum oven (60 °C), followed by the oil extracted by mechanical pressing or the Soxhlet method. From the approximately 72% pulp found in the avocado fruit, the 16% fraction is lipids. The quality indices evaluated in avocado oil showed better results when the pulp was dried at 60 °C under vacuum and oil extraction was done by the Soxhlet method with petroleum ether, whereas the bioactive compounds were better preserved when the avocado pulp was dried at 60 °C under ventilation and mechanical pressing was used for the oil extraction. Among the fatty acids found, oleic acid was the main. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Impact of polymeric membrane filtration of oil sands process water on organic compounds quantification.

    Science.gov (United States)

    Moustafa, Ahmed M A; Kim, Eun-Sik; Alpatova, Alla; Sun, Nian; Smith, Scott; Kang, Seoktae; Gamal El-Din, Mohamed

    2014-01-01

    The interaction between organic fractions in oil sands process-affected water (OSPW) and three polymeric membranes with varying hydrophilicity (nylon, polyvinylidene fluoride and polytetrafluoroethylene) at different pHs was studied to evaluate the impact of filtration on the quantification of acid-extractable fraction (AEF) and naphthenic acids (NAs). Four functional groups predominated in OSPW (amine, phosphoryl, carboxyl and hydroxyl) as indicated by the linear programming method. The nylon membranes were the most hydrophilic and exhibited the lowest AEF removal at pH of 8.7. However, the adsorption of AEF on the membranes increased as the pH of OSPW decreased due to hydrophobic interactions between the membrane surfaces and the protonated molecules. The use of ultra pressure liquid chromatography-high resolution mass spectrometry (UPLC/HRMS) showed insignificant adsorption of NAs on the tested membranes at pH 8.7. However, 26±2.4% adsorption of NAs was observed at pH 5.3 following the protonation of NAs species. For the nylon membrane, excessive carboxylic acids in the commercial NAs caused the formation of negatively charged assisted hydrogen bonds, resulting in increased adsorption at pH 8.2 (25%) as compared to OSPW (0%). The use of membranes for filtration of soluble compounds from complex oily wastewaters before quantification analysis of AEF and NAs should be examined prior to application.

  5. Permanganate oxidation of sulfur compounds to prevent poisoning of Pd catalysts in water treatment processes.

    Science.gov (United States)

    Angeles-Wedler, Dalia; Mackenzie, Katrin; Kopinke, Frank-Dieter

    2008-08-01

    The practical application of Pd-catalyzed water treatment processes is impeded by catalyst poisoning by reduced sulfur compounds (RSCs). In this study, the potential of permanganate as a selective oxidant for the removal of microbially generated RSCs in water and as a regeneration agent for S-poisoned catalysts was evaluated. Hydrodechlorination using Pd/Al2O3 was carried out as a probe reaction in permanganate-pretreated water. The activity of the Pd catalysts in the successfully pretreated reaction medium was similar to that in deionized water. The catalyst showed no deactivation behavior in the presence of permanganate at a concentration level or = 0.08 mM, a significant but temporary inhibition of the catalytic dechlorination was observed. Unprotected Pd/Al2O3, which had been completely poisoned by sulfide, was reactivated by a combined treatment with permanganate and hydrazine. However, the anthropogenic water pollutants thiophene and carbon disulfide were resistant against permanganate. Together with the preoxidation of catalyst poisons, hydrophobic protection of the catalysts was studied. Pd/zeolite and various hydrophobically coated catalysts showed a higher stability against ionic poisons and permanganate than the uncoated catalyst. By means of a combination of oxidative water pretreatment and hydrophobic catalyst protection, we provide a new tool to harness the potential of Pd-catalyzed hydrodehalogenation for the treatment of real waters.

  6. Bioactive compounds and antioxidant activity of fresh and processed white cauliflower.

    Science.gov (United States)

    Ahmed, Fouad A; Ali, Rehab F M

    2013-01-01

    Brassica species are very rich in health-promoting phytochemicals, including phenolic compounds, vitamin C, and minerals. The objective of this study was to investigate the effect of different blanching (i.e., water and steam) and cooking (i.e., water boiling, steam boiling, microwaving, and stir-frying) methods on the nutrient components, phytochemical contents (i.e., polyphenols, carotenoids, flavonoid, and ascorbic acid), antioxidant activity measured by DPPH assay, and phenolic profiles of white cauliflower. Results showed that water boiling and water blanching processes had a great effect on the nutrient components and caused significant losses of dry matter, protein, and mineral and phytochemical contents. However, steam treatments (blanching and cooking), stir-frying, and microwaving presented the lowest reductions. Methanolic extract of fresh cauliflower had significantly the highest antioxidant activity (68.91%) followed by the extracts of steam-blanched, steam-boiled, stir-fried, and microwaved cauliflower 61.83%, 59.15%, 58.93%, and 58.24%, respectively. HPLC analysis revealed that the predominant phenolics of raw cauliflower were protocatechuic acid (192.45), quercetin (202.4), pyrogallol (18.9), vanillic acid (11.90), coumaric acid (6.94), and kaempferol (25.91) mg/100 g DW, respectively.

  7. Treatment of statin compounds by advanced oxidation processes: Kinetic considerations and destruction mechanisms

    Science.gov (United States)

    Razavi, Behnaz; Song, Weihua; Santoke, Hanoz; Cooper, William J.

    2011-03-01

    This study examined the use of advanced oxidation/reduction processes (AO/RPs) for the destruction of cholesterol lowering statin pharmaceuticals. AO/RPs which utilize the oxidizing hydroxyl radical ( rad OH) and reducing aqueous electron (e -aq), to degrade chemical contaminants are alternatives to traditional water treatment methods, and are alternatives as water reuse becomes more generally implemented. Four major statin pharmaceuticals, fluvastatin, lovastatin, pravastatin and simvastatin, were studied, and the absolute bimolecular reaction rate constants with rad OH determined, (6.96±0.16)×10 9, (2.92±0.06)×10 9, (4.16±0.13)×10 9, and (3.13±0.15)×10 9 M -1 s -1, and for e -aq (2.31±0.06)×10 9, (0.45±0.01)×10 9, (1.26±0.01)×10 9, and (0.69±0.02)×10 9 M -1 s -1, respectively. To provide additional information on the radicals formed upon oxidation, transient spectra were measured and the overall reaction efficiency determined. Radical-based destruction mechanisms for destruction of the statins are proposed based on the LC-MS determination of the stable reaction by-products formed using 137Cs γ-irradiation of statin solutions. Knowing the reaction rates, reaction efficiencies and destruction mechanisms of these compounds is essential for the consideration of the use of advanced oxidation/reduction processes for the destruction of statins in aqueous systems.

  8. Treatment of statin compounds by advanced oxidation processes: Kinetic considerations and destruction mechanisms

    International Nuclear Information System (INIS)

    Razavi, Behnaz; Song Weihua; Santoke, Hanoz; Cooper, William J.

    2011-01-01

    This study examined the use of advanced oxidation/reduction processes (AO/RPs) for the destruction of cholesterol lowering statin pharmaceuticals. AO/RPs which utilize the oxidizing hydroxyl radical ( · OH) and reducing aqueous electron (e - aq ), to degrade chemical contaminants are alternatives to traditional water treatment methods, and are alternatives as water reuse becomes more generally implemented. Four major statin pharmaceuticals, fluvastatin, lovastatin, pravastatin and simvastatin, were studied, and the absolute bimolecular reaction rate constants with · OH determined, (6.96±0.16)x10 9 , (2.92±0.06)x10 9 , (4.16±0.13)x10 9 , and (3.13±0.15)x10 9 M -1 s -1 , and for e - aq (2.31±0.06)x10 9 , (0.45±0.01)x10 9 , (1.26±0.01)x10 9 , and (0.69±0.02)x10 9 M -1 s -1 , respectively. To provide additional information on the radicals formed upon oxidation, transient spectra were measured and the overall reaction efficiency determined. Radical-based destruction mechanisms for destruction of the statins are proposed based on the LC-MS determination of the stable reaction by-products formed using 137 Cs γ-irradiation of statin solutions. Knowing the reaction rates, reaction efficiencies and destruction mechanisms of these compounds is essential for the consideration of the use of advanced oxidation/reduction processes for the destruction of statins in aqueous systems.

  9. Treatment of statin compounds by advanced oxidation processes: Kinetic considerations and destruction mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Razavi, Behnaz, E-mail: brazavi@uci.ed [Urban Water Research Center, Department of Civil and Environmental Engineering, University of California, Irvine, Irvine, CA 92697-2175 (United States); Song Weihua, E-mail: wsong@uci.ed [Urban Water Research Center, Department of Civil and Environmental Engineering, University of California, Irvine, Irvine, CA 92697-2175 (United States); Santoke, Hanoz, E-mail: hsantoke@uci.ed [Urban Water Research Center, Department of Civil and Environmental Engineering, University of California, Irvine, Irvine, CA 92697-2175 (United States); Cooper, William J., E-mail: wcooper@uci.ed [Urban Water Research Center, Department of Civil and Environmental Engineering, University of California, Irvine, Irvine, CA 92697-2175 (United States)

    2011-03-15

    This study examined the use of advanced oxidation/reduction processes (AO/RPs) for the destruction of cholesterol lowering statin pharmaceuticals. AO/RPs which utilize the oxidizing hydroxyl radical ({sup {center_dot}O}H) and reducing aqueous electron (e{sup -}{sub aq}), to degrade chemical contaminants are alternatives to traditional water treatment methods, and are alternatives as water reuse becomes more generally implemented. Four major statin pharmaceuticals, fluvastatin, lovastatin, pravastatin and simvastatin, were studied, and the absolute bimolecular reaction rate constants with {sup {center_dot}O}H determined, (6.96{+-}0.16)x10{sup 9}, (2.92{+-}0.06)x10{sup 9}, (4.16{+-}0.13)x10{sup 9}, and (3.13{+-}0.15)x10{sup 9} M{sup -1} s{sup -1}, and for e{sup -}{sub aq} (2.31{+-}0.06)x10{sup 9}, (0.45{+-}0.01)x10{sup 9}, (1.26{+-}0.01)x10{sup 9}, and (0.69{+-}0.02)x10{sup 9} M{sup -1} s{sup -1}, respectively. To provide additional information on the radicals formed upon oxidation, transient spectra were measured and the overall reaction efficiency determined. Radical-based destruction mechanisms for destruction of the statins are proposed based on the LC-MS determination of the stable reaction by-products formed using {sup 137}Cs {gamma}-irradiation of statin solutions. Knowing the reaction rates, reaction efficiencies and destruction mechanisms of these compounds is essential for the consideration of the use of advanced oxidation/reduction processes for the destruction of statins in aqueous systems.

  10. An overview of health-promoting compounds of broccoli (Brassica oleracea var. italica) and the effect of processing.

    Science.gov (United States)

    Mahn, Andrea; Reyes, Alejandro

    2012-12-01

    Broccoli offers many heath-promoting properties owing to its content of antioxidant and anticarcinogenic compounds. The concentration and bioavailability of polyphenols, glucosinolates, sulforaphane and selenium depend on plant biochemistry, cultivation strategy and type of processing. In this article, the main biochemical properties of broccoli are reviewed regarding their health-promoting effects. Additionally, the way these properties are affected by processing is discussed. Steaming and drying result in an apparent increment of sulforaphane content as well as antioxidant activity, most likely due to an increase of the extractability of antioxidants and sulforaphane. Freezing and boiling diminish polyphenols concentration, mainly due to volatilization and leaching into the cooking water. In view of these results, the optimization of broccoli processing in order to maximize the content of bioactive compounds should be possible. The effect of processing on selenium compounds has been poorly studied so far, and therefore this topic should be investigated in the future. Finally, the effect of operating conditions in different drying processes on the content of bioactive compounds in broccoli should be investigated in a greater depth.

  11. Synthesis of BiFeO3 by carbonate precipitation

    Indian Academy of Sciences (India)

    tional ceramic synthesis approach of mixing and heating the oxides of Bi and Fe ... −1 . Phase identification was carried out by X-ray powder diffraction using a PAN analytic ... of the total Fe ions in the starting solution have entered the. Bi2CO5 ...

  12. Study of bioactive compounds in spices (Syzygium aromaticum L, Cinnamomum zeylanicum Blume and Myristica fragrans Houtt) processed by ionizing radiation

    International Nuclear Information System (INIS)

    Duarte, Renato Cesar

    2014-01-01

    Spices and aromatic herbs are divided into leaves, flowers, bud, seeds bark or dry roots from different plants and it is possible to define them as products of highly flavored vegetal origin that volatize easily when incorporated in small quantities to food products and contribute to its aroma, flavor, color or even to its preservation. Nowadays, people look for its functional properties, bioactive compounds and sensory qualities. A big problem is the reduction of the quantity of these compounds throughout the production chain from the harvest process, storage and distribution. For a long time researchers and industries have concentrated on perfecting the processes of the production chain seeking to guarantee the sanitary and food safety, preserving foodstuffs for a long period and an increase in its lifespan without drastically altering its properties. Due to homemade products and the lack of compliance with good practices in its production chain, the spices can contain a high amount of microbiology causing serious complications to the health of the consumer and the radiation processing is often used for reduce these problems. With this finding, the objectives of this work were: Analyze the oil antifungal properties of spices irradiated with average doses (2.5; 5; 7.5 and 10 kGy); Study the average doses (5 and 10 kGy) and high dose (20 and 30 kGy) effects of gamma radiation 60 Co in the bioactive compounds of the spices - cloves, cinnamon and nutmeg; Identify the oils compounds; Identify the volatile compounds in the headspace of the oils and the in natura spices. Identify the compounds of the nonvolatile part of the nutmeg; Identify the chiral compounds of the cinnamon. Comparing the control samples (not irradiated) with the processed at the described doses, regarding the oil antifungal properties it was possible to verify the efficiency and later that the irradiation did not interfered in its efficiency; Regarding to the others tests in this work, the compounds

  13. Modelling of the Kinetics of Sulfure Compounds in Desulfurisation Processes Based on Industry Data of Plant

    Directory of Open Access Journals (Sweden)

    Krivtcova Nadezhda

    2016-01-01

    Full Text Available Modelling of sulfur compounds kinetics was performed, including kinetics of benzothiophene and dibenzothiophene homologues. Modelling is based on experimental data obtained from monitoring of industrial hydrotreating set. Obtained results include kinetic parameters of reactions.

  14. Modelling of the Kinetics of Sulfure Compounds in Desulfurisation Processes Based on Industry Data of Plant

    OpenAIRE

    Krivtsova, Nadezhda Igorevna; Tataurshikov, A.; Kotkova, Elena

    2016-01-01

    Modelling of sulfur compounds kinetics was performed, including kinetics of benzothiophene and dibenzothiophene homologues. Modelling is based on experimental data obtained from monitoring of industrial hydrotreating set. Obtained results include kinetic parameters of reactions.

  15. The average angular distribution of emitted particles in multi-step compound processes

    International Nuclear Information System (INIS)

    Bonetti, R.; Carlson, B.V.; Hussein, M.S.; Toledo, A.S. de

    1983-05-01

    A simple model for the differential cross-section that describes the angular distribution of emitted particles in heavy-ion induced multi-step compound reactions, is constructed. It is suggested that through a careful analysis of the deviations of the experimental data from the pure Hauser-Feshbach behaviour may shed light on the physical nature of the pre-compound, heavy-ion configuration. (Author) [pt

  16. Corrosion Processes of the CANDU Steam Generator Materials in the Presence of Silicon Compounds

    International Nuclear Information System (INIS)

    Lucan, Dumitra; Fulger, Manuela; Velciu, Lucian; Lucan, Georgiana; Jinescu, Gheorghita

    2006-01-01

    The feedwater that enters the steam generators (SG) under normal operating conditions is extremely pure but, however, it contains low levels (generally in the μg/l concentration range) of impurities such as iron, chloride, sulphate, silicate, etc. When water is converted into steam and exits the steam generator, the non-volatile impurities are left behind. As a result of their concentration, the bulk steam generator water is considerably higher than the one in the feedwater. Nevertheless, the concentrations of corrosive impurities are in general sufficiently low so that the bulk water is not significantly aggressive towards steam generator materials. The impurities and corrosion products existing in the steam generator concentrate in the porous deposits on the steam generator tubesheet. The chemical reactions that take place between the components of concentrated solutions generate an aggressive environment. The presence of this environment and of the tubesheet crevices lead to localized corrosion and thus the same tubes cannot ensure the heat transfer between the fluids of the primary and secondary circuits. Thus, it becomes necessary the understanding of the corrosion process that develops into SG secondary side. The purpose of this paper is the assessment of corrosion behavior of the tubes materials (Incoloy-800) at the normal secondary circuit parameters (temperature = 2600 deg C, pressure = 5.1 MPa). The testing environment was demineralized water containing silicon compounds, at a pH=9.5 regulated with morpholine and cyclohexyl-amine (all volatile treatment - AVT). The paper presents the results of metallographic examinations as well as the results of electrochemical measurements. (authors)

  17. Characterization of rhenium compounds obtained by electrochemical synthesis after aging process

    Energy Technology Data Exchange (ETDEWEB)

    Vargas-Uscategui, Alejandro, E-mail: avargasuscat@ing.uchile.cl [Departamento de Ingeniería de Minas, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Tupper Av. 2069, Santiago (Chile); Mosquera, Edgar [Laboratorio de Materiales a Nanoescala, Departamento de Ciencia de los Materiales, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Tupper Av. 2069, Santiago (Chile); López-Encarnación, Juan M. [Department of Mathematics-Physics and Department of Chemistry, University of Puerto Rico at Cayey, 205 Ave. Antonio R. Barceló, Cayey, PR 00736, USA. (Puerto Rico); Chornik, Boris [Departamento de Física, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Blanco Encalada Av. 2008, Santiago (Chile); Katiyar, Ram S. [Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico San Juan, San Juan, PR 00931-3343 (United States); Cifuentes, Luis [Departamento de Ingeniería de Minas, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Tupper Av. 2069, Santiago (Chile)

    2014-12-15

    The proper identification of the molecular nature of the aged rhenium compound obtained by means of electrodeposition from an alkaline aqueous electrolyte was determined. Chemical, structural and vibrational experimental characterization of the aged Re compound showed agreement with quantum-computations, thereby allowing the unambiguous identification of the Re compound as H(ReO{sub 4})H{sub 2}O. - Graphical abstract: Rhenium oxides were electrodeposited on a copper surface and after environmental aging was formed the H(ReO{sub 4})H{sub 2}O compound. The characterization of the synthesized material was made through the comparison of experimental evidence with quantum mechanical computations carried out by means of density functional theory (DFT). - Highlights: • Aged rhenium compound obtained by means of electrodeposition was studied. • The study was made by combining experimental and DFT-computational information. • The aged electrodeposited material is consistent with the H(ReO{sub 4})H{sub 2}O compound.

  18. Efficient rare-event simulation for multiple jump events in regularly varying random walks and compound Poisson processes

    NARCIS (Netherlands)

    B. Chen (Bohan); J. Blanchet; C.H. Rhee (Chang-Han); A.P. Zwart (Bert)

    2017-01-01

    textabstractWe propose a class of strongly efficient rare event simulation estimators for random walks and compound Poisson processes with a regularly varying increment/jump-size distribution in a general large deviations regime. Our estimator is based on an importance sampling strategy that hinges

  19. Nonparametric estimation of the heterogeneity of a random medium using compound Poisson process modeling of wave multiple scattering.

    Science.gov (United States)

    Le Bihan, Nicolas; Margerin, Ludovic

    2009-07-01

    In this paper, we present a nonparametric method to estimate the heterogeneity of a random medium from the angular distribution of intensity of waves transmitted through a slab of random material. Our approach is based on the modeling of forward multiple scattering using compound Poisson processes on compact Lie groups. The estimation technique is validated through numerical simulations based on radiative transfer theory.

  20. Impact of sorghum processing on phytate, phenolic compounds and in vitro solubility of iron and zinc in thick porridges

    NARCIS (Netherlands)

    Kayodé, A.P.P.; Linnemann, A.R.; Nout, M.J.R.; Boekel, van M.A.J.S.

    2007-01-01

    This study focussed on the impact of process variables on levels of phytate and phenolic compounds, and in vitro solubility of iron (Fe) and zinc (Zn) in sorghum porridges, a major staple in semi-arid tropics. The aim was to identify practices that enhance the mineral availability in this type of

  1. The efficiency of superficially active compounds on the process of decontamination in animals exposed to various doses of ionizing radiation

    International Nuclear Information System (INIS)

    Kossakowski, S.

    1977-01-01

    The efficiency of some superficially active compounds on the process of decontamination was investigated in swine exposed to various doses of ionizing radiation (300, 600 R), and then contaminated with 90 Sr, 131 I, 137 Cs, and 144 Ce. The results revealed that the time factor after irradiation was more important for the efficiency of decontamination than the doses of radiation. (author)

  2. Application of advanced oxidation process by electron beam irradiation in the organic compounds degradation present in industrial effluents

    International Nuclear Information System (INIS)

    Duarte, Celina Lopes

    1999-01-01

    The inefficacy of conventional methods to destroy toxic organic compounds present in industrial effluent has taken the search for new technologies of treatment. he water irradiation is the most efficient process to generate radicals that mineralise these compounds. A study to evaluate the Advanced Oxidation Process by electron beam irradiation to treat industrial effluent with high toxic organic compounds concentration was carried out. Experiments were conducted using a Radiation Dynamics Electron Beam Accelerator with 1,5 MeV energy and 37 power. The effluent samples from a big industrial complex were irradiated using the IPEN's Liquid Effluent Irradiation Pilot Plant and the effluent samples from five steps of a Governmental Wastewater Treatment Plant from SABESP - ETE Suzano (industrial Receiver Unit, Coarse Bar Screens, Medium Bar Screens, Primary Sedimentation and Final Effluent), were irradiated in a batch system. The electron beam irradiation showed be efficient on destroying the organic compounds delivered in these effluents mainly chloroform, dichloroethane, methyl isobutyl ketone, benzene, toluene, xylene, phenol and in the decoloring of dyes present in some samples. To remove 90% of the most organic compounds was necessary a 20 kGy dose for industry's ETE, 20 kGy for IRU, CBS and MBS and 10 kGy to 20 kGy for PS and FE. (author)

  3. Impact of sorghum processing on phytate, phenolic compounds and in vitro solubility of iron and zinc in thick porridges

    OpenAIRE

    Kayodé, A.P.P.; Linnemann, A.R.; Nout, M.J.R.; Boekel, van, M.A.J.S.

    2007-01-01

    This study focussed on the impact of process variables on levels of phytate and phenolic compounds, and in vitro solubility of iron (Fe) and zinc (Zn) in sorghum porridges, a major staple in semi-arid tropics. The aim was to identify practices that enhance the mineral availability in this type of staple food. We studied the example of the West African porridge `dibou' for which the processing methods involve grain cleaning, milling, sieving and cooking. Regional variations occur in the proces...

  4. Effects of high pressure processing on fatty acid composition and volatile compounds in Korean native black goat meat.

    Science.gov (United States)

    Kang, Geunho; Cho, Soohyun; Seong, Pilnam; Park, Beomyoung; Kim, Sangwoo; Kim, Donghun; Kim, Youngjun; Kang, Sunmun; Park, Kyoungmi

    2013-08-01

    This study investigated the effects of high pressure processing (HPP) on fatty acid composition and volatile compounds in Korean native black goat (KNBG) meat. Fatty acid content in KNBG meat was not significantly (p > 0.05) different among the control goats and those subjected HPP. The 9,12-octadecadienoic acid and octadecanoic acid, well-known causes of off-flavors, were detected from meat of some KNBG. A difference between the control and HPP treatment was observed in the discriminated function analysis using an electronic nose. The results suggest that the volatile compounds in KNBG meat were affected by HPP.

  5. Clean recovery of antioxidant compounds from plant foods, by-products and algae assisted by ultrasounds processing. Modeling approaches to optimize processing conditions

    DEFF Research Database (Denmark)

    Roselló-Soto, Elena; Galanakis, Charis M.; Brnčić, Mladen

    2015-01-01

    Ultrasound treatment is an alternative affordable, effective and reproducible method for the improved recovery of bioactive compounds from various processing streams. The objective of this review is to discuss the impact of ultrasound-assisted extraction on the recovery of polyphenols, carotenoid...

  6. Microfabricated ommatidia using a laser induced self-writing process for high resolution artificial compound eye optical systems.

    Science.gov (United States)

    Jung, Hyukjin; Jeong, Ki-Hun

    2009-08-17

    A microfabricated compound eye, comparable to a natural compound eye shows a spherical arrangement of integrated optical units called artificial ommatidia. Each consists of a self-aligned microlens and waveguide. The increase of waveguide length is imperative to obtain high resolution images through an artificial compound eye for wide field-of - view imaging as well as fast motion detection. This work presents an effective method for increasing the waveguide length of artificial ommatidium using a laser induced self-writing process in a photosensitive polymer resin. The numerical and experimental results show the uniform formation of waveguides and the increment of waveguide length over 850 microm. (c) 2009 Optical Society of America

  7. Functional food productions: release the potential of bioactive compounds through food processing

    Science.gov (United States)

    Epidemiological studies of bioactive compounds from plant-based foods have consistently pointed to undisputed benefits of consumption of plant-based foods on human health particularly regarding cardiovascular diseases and cancers. However, in order to attain the dosage required from these studies, p...

  8. Bioactive compounds in edible flowers processed by radiation; Compostos bioativos em flores comestiveis processadas por radiacao

    Energy Technology Data Exchange (ETDEWEB)

    Koike, Amanda Cristina Ramos

    2015-07-01

    Edible flowers are increasingly being used in culinary preparations, being also recognized for their potential valuable effects in human health, which require new approaches to improve their conservation and safety. These highly perishable products should be grown without using any pesticide. Irradiation treatment might be the answer to these problems, ensuring food quality, increasing shelf-life and disinfestation of foods. Irradiation treatment might be the answer to these problems, to ensure food quality, to increase shelf-life and disinfestation of foods. Tropaeolum majus L. (nasturtium) and Viola tricolor L. (johnny-jump-up) flowers are widely used in culinary preparations, being also acknowledged for their antioxidant properties and high content of phenolics. The purpose of this study was to evaluate the dose-dependent effects of gamma and electron beam irradiation (doses of 0, 0.5, 0.8 and 1 kGy) on the antioxidant activity, phenolic compounds, physical aspects and antiproliferative potential of edible flowers. Kaempferol-O-hexoside-O-hexoside was the most abundant compound in all samples of Tropaeolum majus flower while pelargonidin-3-O-sophoroside was the major anthocyanin. In general, irradiated samples gave higher antioxidant activity, probably due to their higher amounts of phenolic compounds, which were also favored by the 1.0 kGy dose, regardless of the source . The Viola tricolor samples displayed flavonols as the most abundant phenolic compounds, particularly those derived from quercetin. In general, gamma-irradiated samples, independently of the applied dose, showed higher amounts in phenolic compounds, which were also favored by the 1.0 kGy dose, regardless of the source. The antioxidant activity was also higher among irradiated samples. The two species of edible flowers have not provided the samples did not show potential antiproliferative and cytotoxicity. Accordingly, the applied irradiation treatments seemed to represent a feasible technology

  9. Total recovery of the waste of two-phase olive oil processing: isolation of added-value compounds.

    Science.gov (United States)

    Fernández-Bolaños, Juan; Rodríguez, Guillermo; Gómez, Esther; Guillén, Rafael; Jiménez, Ana; Heredia, Antonia; Rodríguez, Rocío

    2004-09-22

    A process for the value addition of solid waste from two-phase olive oil extraction or "alperujo" that includes a hydrothermal treatment has been suggested. In this treatment an autohydrolysis process occurs and the solid olive byproduct is partially solubilized. From this water-soluble fraction can be obtained besides the antioxidant hydroxytyrosol several other compounds of high added value. In this paper three different samples of alperujo were characterized and subjected to a hydrothermal treatment with and without acid catalyst. The main soluble compounds after the hydrolysis were represented by monosaccharides xylose, arabinose, and glucose; oligosaccharides, mannitol and products of sugar destruction. Oligosaccharides were separated by size exclusion chromatography. It was possible to get highly purified mannitol by applying a simple purification method.

  10. Extraction of carbon 14-labeled compounds from plant tissue during processing for electron microscopy

    International Nuclear Information System (INIS)

    Coetzee, J.; van der Merwe, C.F.

    1989-01-01

    Loss of 14 C-labeled compounds from bean leaf tissue was monitored during all the stages of routine specimen preparation. No significant differences in extraction were associated with the use of acetone, ethanol, or dioxane as dehydration fluids. Fixation at low temperature increased the loss of label. Prolonged fixation in glutaraldehyde increased the loss, but fixation in osmium solutions for periods as long as 4 hr had no influence on extraction. Buffer rinses and dehydration fluids caused appreciable amounts of label to be extracted. The use of propylene oxide as transition fluid resulted in low extraction. Some embedding media caused the loss of small amounts of labeled compounds, but one of the media tested (LR-white) extracted significant amounts of label

  11. The Formation of Organic Compounds of Astrobiological Interest by the Irradiation Processing of Astrophysical Ices

    Science.gov (United States)

    Sandford, Scott A.

    2015-01-01

    Many environments in space contain very low temperature mixed molecular ices that are exposed to ionizing radiation in the form of cosmic rays and high-energy photons. While traditional chemistry would not be expected to occur at the temperatures typical of these ices (T compounds. Many of these new products are of direct interest to astrobiology. For example, the irradiation of mixed molecular ices has been shown to produce amino acids, amphiphiles, quinones, sugars, heterocyclic compounds, and nucleobases, all molecular building blocks used by terrestrial life. Insofar as the presence of these materials plays a role in the origin of life on planets, this has profound implications for the potential abundance of life in the universe since these experiments simulate universal conditions that are expected to be found wherever new stars and planets form.

  12. Optimization of Malaxation Process using Major Aroma Compounds in Virgin Olive Oil

    OpenAIRE

    Cevik,Serife; Ozkan,Gulcan; Kıralan,Mustafa

    2016-01-01

    ABSTRACT Optimization of major aroma compounds in olive oils produced from fruits at three maturity stages wasstudied. A central composite design was used for the optimization of malaxation conditions of temperature and times, each at five levels with 13 runs including five central points. The responses of interest were trans-2-hexenal and hexanal, which were investigated and their contents were optimized. A full quadratic second order regression model including the linear, quadratic, and two...

  13. The content changes of selected phenolic compounds during processing of medicinal plants

    OpenAIRE

    GROŠAFTOVÁ, Blanka

    2007-01-01

    This work was aimed to the problem of change of the content of selected phenolic substances during treatment and storage of medical plants. Flavonoids represent small, but very important group of phenolic compounds. The biggest attention was paid to quercetin and rutine.Content of phenolic substances was determined by method of micellar electrokinetic capillary chromatography (MECC) in case of 6 medicinal plants usually used in traditional and modern medicine.

  14. Analysis of Wastewater for Organic Compounds Unique to RDX/HMX manufacturing and Processing

    Science.gov (United States)

    1979-12-01

    manufacture of acetic anhydride and the concentration of weak acetic acid, recovered at Area B, to yield * Holston Defense Corporation 2 Kingsport...washing nor Soxhlet extraction techniques proved to be effective in recovering the organic compounds from the type of activated carbon available at the...ice ?nd acetone mixture.J Approximately one liter of dewater yielded approximately 200 mg (0.2 grams) of freeze-dried solids: These solids were

  15. THE ISOLATION OF COMPOUND POLYPHENOL FROM WAJO DISTRICT CACAO BEAN AND CACAO WASTE THROUGH FERMENTATION PROCESS

    Directory of Open Access Journals (Sweden)

    Muhammad Wijaya

    2016-10-01

    Full Text Available This research aims to utilize the liquid smoke, charcoal, oil and gas that have been produced from cocoa waste shell from fast pyrolysis technology at 125-500 oC. The charcoal of the cocoa waste was analyzed using a bomb calorimeter at 5925 cal/g showed that it contains 52.02% of lignin; 17.27% of alpha cellulose and 19.56% of hemicellulose, respectively. The HPLC analysis of Wajo district cacao bean resulted in polyphenol compound as 308.35. GC-MS analysis of cocoa shell liquid smoke that pyrolized at 125-500 oC produces severals compounds such as acetic acid, n-buthane, methyl esther, propanoac acid, butanoac acid, methyl pyridine, 1-hydroxy-2-propanone, and mequinol. The FTIR analysis of cocoa bean showed a hydroxyl group at 3450.65 cm-1, carbonyl group at 1730.15 cm-1, CH group at 719.45-607.58 cm-1. The crystallinity degree of Wajo District cocoa shell analyzed using XRD was 26,50%. The existence of chemical compounds in liquid smoke products have been found as raw chemicals.  Content of biomass carbon at these cacao waste increased according to the increase of pyrolisis temperature, while the carbon emission of these three materials decreased as the temperature increased. Compound polyphenol from cacao bean has a potent as anti oxidant that is friendly  for environmental and healthy.   Keywords: cacao  bean, fermentation,  polyphenol,  and  chemical

  16. Stability of phenolic compounds of the propolis processed by ionizing radiation

    International Nuclear Information System (INIS)

    Matsuda, Andrea H.; Mastro, Nelida L. del

    2002-01-01

    Propolis is the generic term of a resin of different colors and consistency collected by bees, Apis mellifera, from diverse parts of plants, buds and resinous exudates. It possesses antibacterial , antifungal and antiviral properties and many other biological activities such as antiinflammatory, antiulcer, local anaesthetic, antitumor, etc. The aim of this work is to study the effect of 60 Co ionizing radiation on the stability of phenolic compounds of propolis. (author)

  17. Atmospheric Release of Organic Chlorinated Compounds from the Activated-Sludge Wastewater Treatment Process.

    Science.gov (United States)

    1980-05-01

    representing 26 industry types were tested in this desorption apparatus. Sixty-four (85%) contained 6 detectable air- strippable fractions. Thibodeaux and...retardants such as Hex, chlordane, chlordene, aldrin and isodrin. Only three test compounds (Hex-BCH, Hex-VCL and chlordene) were selected for...detergent level was selected as a test parameter because oxygen transfer in aerated aqueous solution is influenced by surfactant concentration. A minimum

  18. Occurrence of pharmaceutical compounds in wastewater process streams in Dublin, Ireland.

    Science.gov (United States)

    Lacey, Clair; Basha, Shaik; Morrissey, Anne; Tobin, John M

    2012-01-01

    The aim of this work is to establish baseline levels of pharmaceuticals in three wastewater treatment plant (WWTP) streams in the greater Dublin region to assess the removal efficiency of the selected WWTPs and to investigate the existence of any seasonal variability. Twenty compounds including several classes of antibiotics, acidic and basic pharmaceuticals, and prescribed medications were selected for investigation using a combination of membrane filtration, solid phase extraction (SPE) cleanup, and liquid chromatography-electrospray ionization tandem mass spectrometry. Fourteen of the selected compounds were found in the samples. Increased effluent concentrations, compared to influent concentrations, for a number of compounds (carbamazepine, clotrimazole, propranolol, nimesulide, furosemide, mefenamic acid, diclofenac, metoprolol, and gemfibrozil) were observed. The detected concentrations were generally below toxicity levels and based on current knowledge are unlikely to pose any threat to aquatic species. Mefenamic acid concentrations detected in both Leixlip and Swords effluents may potentially exert ecotoxicological effects with maximum risk quotients (i.e., ratio of predicted exposure concentration to predicted no effect concentration) of 4.04 and 1.33, respectively.

  19. Taste-active compound levels in Korean native chicken meat: The effects of bird age and the cooking process.

    Science.gov (United States)

    Jayasena, Dinesh D; Jung, Samooel; Kim, Hyun Joo; Yong, Hae In; Nam, Ki Chang; Jo, Cheorun

    2015-08-01

    The effects of bird age and the cooking process on the levels of several taste-active compounds, including inosine 5'-monophosphate (IMP), glutamic acid, cysteine, reducing sugars, as well as oleic, linoleic, arachidonic, and docosahexaenoic acids (DHA), in the breast and leg meats from a certified meat-type commercial Korean native chicken (KNC) strain (Woorimatdag) were investigated. KNC cocks were raised under similar standard conditions at a commercial chicken farm, and breast and leg meats from birds of various ages (10, 11, 12, 13, and 14 wk; 10 birds/age group) were obtained. After raw and cooked meat samples were prepared, they were analyzed for the aforementioned taste-active compounds. Compared to the leg meat, KNC breast meat had higher levels of IMP, arachidonic acid, and DHA, but lower levels of the other taste-active compounds (P cooking process (P cooking process. This information could be useful for selection and breeding programs, and for popularizing native chicken meat. © 2015 Poultry Science Association Inc.

  20. Phenolic compounds removal from mimosa tannin model water and olive mill wastewater by energy-efficient electrocoagulation process

    Directory of Open Access Journals (Sweden)

    Marijana Kraljić Roković

    2014-12-01

    Full Text Available The objective of this work was to study the influence of NaCl concentration, time, and current density on the removal efficiency of phenolic compounds by electrocoagulation process, as well as to compare the specific energy consumption (SEC of these processes under different experimental conditions. Electrocoagulation was carried out on two different samples of water: model water of mimosa tannin and olive mill wastewater (OMW. Low carbon steel electrodes were used in the experiments. The properties of the treated effluent were determined using UV/Vis spectroscopy and by measuring total organic carbon (TOC. Percentage of removal increased with time, current density, and NaCl concentration. SEC value increased with increased time and current density but it was decreased significantly by NaCl additions (0-29 g L-1. It was found that electro­coagulation treatment of effluents containing phenolic compounds involves complex formation between ferrous/ferric and phenolic compounds present in treated effluent, which has significant impact on the efficiency of the process.

  1. Processing ‘Ataulfo’ Mango into Juice Preserves the Bioavailability and Antioxidant Capacity of Its Phenolic Compounds

    Directory of Open Access Journals (Sweden)

    Ana Elena Quirós-Sauceda

    2017-09-01

    Full Text Available The health-promoting effects of phenolic compounds depend on their bioaccessibility from the food matrix and their consequent bioavailability. We carried out a randomized crossover pilot clinical trial to evaluate the matrix effect (raw flesh and juice of ‘Ataulfo’ mango on the bioavailability of its phenolic compounds. Twelve healthy male subjects consumed a dose of mango flesh or juice. Blood was collected for six hours after consumption, and urine for 24 h. Plasma and urine phenolics were analyzed by electrochemical detection coupled to high performance liquid chromatography (HPLC-ECD. Five compounds were identified and quantified in plasma. Six phenolic compounds, plus a microbial metabolite (pyrogallol were quantified in urine, suggesting colonic metabolism. The maximum plasma concentration (Cmax occurred 2–4 h after consumption; excretion rates were maximum at 8–24 h. Mango flesh contributed to greater protocatechuic acid absorption (49%, mango juice contributed to higher chlorogenic acid absorption (62%. Our data suggests that the bioavailability and antioxidant capacity of mango phenolics is preserved, and may be increased when the flesh is processed into juice.

  2. Changes in guava (Psidium guajava L. var. Paluma nectar volatile compounds concentration due to thermal processing and storage

    Directory of Open Access Journals (Sweden)

    Maria Ivaneide Coutinho Correa

    2010-12-01

    Full Text Available Guava nectars were formulated for approximately 10, 12, or 14 ºBrix, with 40% guava pulp. Sodium benzoate, 500 mg.kg-1 was used as preservative. The Brix value was adjusted with saturated sucrose syrup. The guava nectar was pasteurized (85 ºC/42 seconds in tubular heat exchanger and then hot filled in 500 mL white glass bottles. The products were stored either at room temperature (25 ± 5 ºC or refrigerated (5 ± 2 ºC under fluorescent light exposure and analyzed on the day after processing (time zero and also 40, 80, and 120 days of storage. Eight compounds were identified and quantified by Gas Chromatography (GC -Mass Spectrometry (MS: hexanal, (E-hex-2-enal, 1-hexenol, (Z-hex-3-enol, (Z-hex-3-enyl acetate, phenyl-3-propyl acetate, cinnamyl acetate, and acetic acid. There was no significant effect of thermal treatment on the volatile compound concentrations, except for a significant decrease (p = 0.0001 in hexanal and (Z-hex-3-enyl acetate (p = 0.0029. As for the storage time, there was a much greater decrease in the esters contents, such as (Z-hex-3-enyl and phenyl-3-propyl acetates. Cinnamyl acetate had the greatest decrease over storage time. Refrigeration was better than room temperature for guava nectar volatile compounds stability over storage time, mainly for esters compounds, which are important for the product aroma and flavor

  3. Encapsulation of Active Compounds in Fruit and Vegetable Juice Processing: Current State and Perspectives.

    Science.gov (United States)

    Speranza, Barbara; Petruzzi, Leonardo; Bevilacqua, Antonio; Gallo, Mariangela; Campaniello, Daniela; Sinigaglia, Milena; Corbo, Maria Rosaria

    2017-06-01

    The production of value-added and/or functional juices has increased significantly in recent years, following an increased consumer demand to promote health and/or prevent disease through diet and nutrition. Micro and nano-encapsulation are promising technologies to protect and deliver sensitive compounds, allowing a controlled release in the target sites. This paper offers an overview of current applications, limits and challenges of encapsulation technologies in the production of fruit and vegetable juices, with a particular emphasis on products derived from different botanical sources. © 2017 Institute of Food Technologists®.

  4. Consumer attitude and purchase intention towards processed meat products with natural compounds and a reduced level of nitrite.

    Science.gov (United States)

    Hung, Yung; de Kok, Theo M; Verbeke, Wim

    2016-11-01

    This study investigates consumer attitude and purchase intention towards processed meat products with added natural compounds and a reduced level of nitrite. The rationale for such innovation relates to nitrite's negative health image as a chemical additive among consumers, versus the perception of compounds from fruits and vegetables as being natural and healthy. Cross-sectional data were collected through online questionnaires on knowledge about, interest in, attitude and intentions towards such new type of processed meat products in Belgium, The Netherlands, Italy and Germany (n=2057). Consumers generally had limited knowledge about nitrite being added to meat products. Yet, they expressed favourable attitudes and purchase intentions towards the new processed meat products. Purchase intention associated positively with: attitude; preference for natural over chemical additives; perceived harmfulness of chemical additives; risk importance; domain specific innovativeness; awareness of nitrite added; education; general health interest; and processed meat consumption frequency. Consumers from Italy and Germany had a lower level of purchase intention compared to Belgium. Four consumer segments were identified based on attitude and purchase intention: 'enthusiasts' (39.3% of the sample), 'accepters' (11.9%), 'half-hearted' (42.3%) and 'uninterested' (6.6%). This study provides valuable insight for further product development and effective tailoring of marketing communication strategies of innovative processed meat products. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Multifaceted processes controlling the distribution of hazardous compounds in the spontaneous combustion of coal and the effect of these compounds on human health.

    Science.gov (United States)

    Oliveira, Marcos L S; da Boit, Kátia; Pacheco, Fernanda; Teixeira, Elba C; Schneider, Ismael L; Crissien, Tito J; Pinto, Diana C; Oyaga, Rafael M; Silva, Luis F O

    2018-01-01

    Pollution generated by hazardous elements and persistent organic compounds that affect coal fire is a major environmental concern because of its toxic nature, persistence, and potential risk to human health. The coal mining activities are growing in the state of Santa Catarina in Brazil, thus the collateral impacts on the health and economy are yet to be analyzed. In addition, the environment is also enduring the collateral damage as the waste materials directly influence the coal by-products applied in civil constructions. This study was aimed to establish the relationships between the composition, morphology, and structural characteristics of ultrafine particles emitted by coal mine fires. In Brazil, the self-combustions produced by Al-Ca-Fe-Mg-Si coal spheres are rich in chalcophile elements (As, Cd, Cu, Hg, Pb, Sb, Se, Sn, and Zn), lithophile elements (Ce, Hf, In, La, Th, and U), and siderophile elements (Co, Cr, Mo, Fe, Ni, and V). The relationship between nanomineralogy and the production of hazardous elements as analyzed by advanced methods for the geochemical analysis of different materials were also delineated. The information obtained by the mineral substance analysis may provide a better idea for the understanding of coal-fire development and assessing the response of particular coal in different combustion processes. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Taming hazardous chemistry in flow: The continuous processing of diazo and diazonium compounds

    OpenAIRE

    Deadman, Benjamin J.; Collins, Stuart G.; Maguire, Anita R.

    2014-01-01

    The synthetic utilities of the diazo and diazonium groups are matched only by their reputation for explosive decomposition. Continuous processing technology offers new opportunities to make and use these versatile intermediates at a range of scales with improved safety over traditional batch processes. In this minireview, the state of the art in the continuous flow processing of reactive diazo and diazonium species is discussed.

  7. Synthesis and characterization of organosilicon compounds as novel precursors for CVD processes

    Energy Technology Data Exchange (ETDEWEB)

    Ermakova, E.N.; Sysoev, S.V.; Nikulina, L.D. [Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, Acad. Lavrentiev Ave. 3, Novosibirsk 630090 (Russian Federation); Tsyrendorzhieva, I.P.; Rakhlin, V.I. [Favorskii Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Favorskii Str. 1, Irkutsk 664033 (Russian Federation); Kosinova, M.L., E-mail: marina@niic.nsc.ru [Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, Acad. Lavrentiev Ave. 3, Novosibirsk 630090 (Russian Federation)

    2015-12-20

    Highlights: • The temperature dependences of vapor pressure of four precursors have been measured. • The experimental data were used to calculate standard thermodynamic functions. • The thermodynamic modelling of SiC{sub x}N{sub y} films formation has been performed. - Abstract: Chemical vapor deposition using single-source organosilicon precursors is one of the most effective ways to produce multifunctional SiC{sub x}N{sub y} films. It is worth mentioning that the precursor molecule design affects both the composition and properties of films. Four organosilicon compounds containing a phenyl substituent (namely, trimethylphenylsilane, trimethyl(phenylamino) silane, trimethyl(benzylamino)silane and bis(trimethylsilyl)phenylamine) have been synthesized and characterized as potential CVD precursors for SiC{sub x}N{sub y} films synthesis. The compounds have been shown to be volatile and stable enough to be used in chemical vapor deposition of SiC{sub x}N{sub y} films. Thermodynamic modeling of the film deposition from the gaseous mixture of trimethylphenylsilane and ammonia in Si–C–N–H system has demonstrated that SiC{sub x}N{sub y} films can be deposited, and there is an opportunity to determine the area of appropriate deposition conditions.

  8. Stability of bioactive compounds in minimally processed beet according to the cooking methods

    Directory of Open Access Journals (Sweden)

    Juliana Arruda RAMOS

    2017-10-01

    Full Text Available Abstract The current study aimed to determine the functional propriety of fresh beets under different cooking methods through the quantification of bioactives compounds. Beets were chosen for uniformity of size, color and absence of defects. They were thoroughly washed in running water to remove dirt, manually peeled with a knife, sliced through a stainless-steel food processor (5 mm slicing disc and submitted to four different cooking methods: steaming, pressure, oven-baked and hot-water immersion. Analysis were performed in both uncooked and cooked beets to evaluate antioxidant activity, total phenolic content, carotenoids, flavonoids and betalains. The experiment was completely randomized design (CRD. Data were subjected to analysis of variance (F test and means were compared by Tukey test (p < 0.05. Oven-baked beets preserve most of the bioactive coumpouds, maintaining better levels of carotenoids, flavonoids, betacyanin and betaxanthin than the other cooking methods. The antioxidant activity was similar between the treatments, except in the pressure. Moreover, different cooking methods did not affect phenolic compounds concentration in beets.

  9. Occurrence and fate of antibiotic, analgesic/anti-inflammatory, and antifungal compounds in five wastewater treatment processes.

    Science.gov (United States)

    Guerra, P; Kim, M; Shah, A; Alaee, M; Smyth, S A

    2014-03-01

    The presence of pharmaceuticals and personal care products (PPCPs) in the aquatic environment as a result of wastewater effluent discharge is a concern in many countries. In order to expand our understanding on the occurrence and fate of PPCPs during wastewater treatment processes, 62 antibiotic, analgesic/anti-inflammatory, and antifungal compounds were analyzed in 72 liquid and 24 biosolid samples from six wastewater treatment plants (WWTPs) during the summer and winter seasons of 2010-2012. This is the first scientific study to compare five different wastewater treatment processes: facultative and aerated lagoons, chemically-enhanced primary treatment, secondary activated sludge, and advanced biological nutrient removal. PPCPs were detected in all WWTP influents at median concentrations of 1.5 to 92,000 ng/L, with no seasonal differences. PPCPs were also found in all final effluents at median levels ranging from 3.6 to 4,200 ng/L with higher values during winter (pRemoval efficiencies ranged between -450% and 120%, depending on the compound, WWTP type, and season. Mass balance showed that the fate of analgesic/anti-inflammatory compounds was predominantly biodegradation during biological treatment, while antibiotics and antifungal compounds were more likely to sorb to sludge. However, some PPCPs remained soluble and were detected in effluent samples. Overall, this study highlighted the occurrence and behavior of a large set of PPCPs and determined how their removal is affected by environmental/operational factors in different WWTPs. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

  10. Fate and Prediction of Phenolic Secoiridoid Compounds throughout the Different Stages of the Virgin Olive Oil Making Process.

    Science.gov (United States)

    Fregapane, Giuseppe; Salvador, M Desamparados

    2017-08-03

    The evolution of the main phenolic secoiridoid compounds throughout the different stages of the virgin olive oil making process-crushing, malaxation and liquid-solid separation-is studied here, with the goal of making possible the prediction of the partition and transformation that take place in the different steps of the process. The concentration of hydroxytyrosol secoiridoids produced under the different crushing conditions studied are reasonably proportional to the intensity of the milling stage, and strongly depend on the olive variety processed. During malaxation, the content of the main phenolic secoiridoids is reduced, especially in the case of the hydroxytyrosol derivatives, in which a variety-dependent behaviour is observed. The prediction of the concentration of phenolic secoiridoids finally transferred from the kneaded paste to the virgin olive oil is also feasible, and depends on the phenolic content and amount of water in the olive paste. The determination of the phenolic compounds in the olive fruit, olive paste and olive oil has been carried out by LC-MS (Liquid-Chromatography Mass-Spectrometry). This improved knowledge could help in the use of more adequate processing conditions for the production of virgin olive oil with desired properties; for example, higher or lower phenolic content, as the amount of these minor components is directly related to its sensory, antioxidant and healthy properties.

  11. Effect of Spanish style processing on the phenolic compounds and antioxidant activity of Algerian green table olives

    Energy Technology Data Exchange (ETDEWEB)

    Mettouchi, S.; Sacchi, R.; Ould Moussa, Z.E.D.; Paduano, A.; Savarese, M.; Tamendjari, A.

    2016-07-01

    The study was carried out on seven Algerian olive cultivars to report the effect of Spanish style processing on individual and total phenolic compounds and the changes that occur in antioxidant capacity. The results indicate that the treatment leads to losses in phenolic contents which are cultivar dependent. Sigoise is the least affected variety (12.25%) and Azzeradj from Seddouk the most affected one (94.80%). The phenolic profile shows drastic changes after processing. Hydroxytyrosol is dominant in processed olives (14.42–545.42 mg·100 g−1) while oleuropein is the major phenolic compound in fresh olives (994.27 mg·100 g−1). As a consequence to the loss in phenolic content, substantial reductions in the antioxidant activities of the extracts are noted. They are estimated to be 13.12–92.75% in scavenging activity against the DPPH radical, 37.78–93.98% in reducing capacity, 59.45–97.94% in the hydrogen peroxide radical and 7.26–51.66% in the inhibition bleaching of β-carotene. Among the processed varieties, only Sigoise presented a positive value of RACI (relative antioxidant capacity index). (Author)

  12. Taming hazardous chemistry in flow: the continuous processing of diazo and diazonium compounds.

    Science.gov (United States)

    Deadman, Benjamin J; Collins, Stuart G; Maguire, Anita R

    2015-02-02

    The synthetic utilities of the diazo and diazonium groups are matched only by their reputation for explosive decomposition. Continuous processing technology offers new opportunities to make and use these versatile intermediates at a range of scales with improved safety over traditional batch processes. In this minireview, the state of the art in the continuous flow processing of reactive diazo and diazonium species is discussed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Impact of the industrial freezing process on selected vegetables -Part II. Colour and bioactive compounds

    NARCIS (Netherlands)

    Mazzeo, Teresa; Paciulli, Maria; Chiavaro, Emma; Visconti, Attilio; Fogliano, Vincenzo; Ganino, Tommaso; Pellegrini, Nicoletta

    2015-01-01

    In the present study, the impact of the different steps (i.e. blanching, freezing, storage following the industrial freezing process and the final cooking prior to consumption) of the industrial freezing process was evaluated on colour, chlorophylls, lutein, polyphenols and ascorbic acid content

  14. Jute fiber reinforced polypropylene produced by continuous extrusion compounding. Part 1. Processing and ageing properties

    NARCIS (Netherlands)

    Oever, van den M.J.A.; Snijder, M.H.B.

    2008-01-01

    This article addresses the processing and ageing properties of jute fiber reinforced polypropylene (PP) composites. The composite has been manufactured by a continuous extrusion process and results in free flowing composite granules, comprising up to 50 weight percent (wt %) jute fiber in PP. These

  15. Uniform asymptotics for compound Poisson processes with regularly varying jumps and vanishing drift

    NARCIS (Netherlands)

    Kamphorst, B.; Zwart, B.

    2015-01-01

    This paper addresses heavy-tailed asymptotics of functionals of a class of spectrally one-sided L\\'evy process that remain valid in a near-critical regime. This complements recent similar results that have been obtained for the all-time supremum of such processes. Specifically, we consider local

  16. K-mean clustering algorithm for processing signals from compound semiconductor detectors

    International Nuclear Information System (INIS)

    Tada, Tsutomu; Hitomi, Keitaro; Wu, Yan; Kim, Seong-Yun; Yamazaki, Hiromichi; Ishii, Keizo

    2011-01-01

    The K-mean clustering algorithm was employed for processing signal waveforms from TlBr detectors. The signal waveforms were classified based on its shape reflecting the charge collection process in the detector. The classified signal waveforms were processed individually to suppress the pulse height variation of signals due to the charge collection loss. The obtained energy resolution of a 137 Cs spectrum measured with a 0.5 mm thick TlBr detector was 1.3% FWHM by employing 500 clusters.

  17. Conception through build of an automated liquids processing system for compound management in a low-humidity environment.

    Science.gov (United States)

    Belval, Richard; Alamir, Ab; Corte, Christopher; DiValentino, Justin; Fernandes, James; Frerking, Stuart; Jenkins, Derek; Rogers, George; Sanville-Ross, Mary; Sledziona, Cindy; Taylor, Paul

    2012-12-01

    Boehringer Ingelheim's Automated Liquids Processing System (ALPS) in Ridgefield, Connecticut, was built to accommodate all compound solution-based operations following dissolution in neat DMSO. Process analysis resulted in the design of two nearly identical conveyor-based subsystems, each capable of executing 1400 × 384-well plate or punch tube replicates per batch. Two parallel-positioned subsystems are capable of independent execution or alternatively executed as a unified system for more complex or higher throughput processes. Primary ALPS functions include creation of high-throughput screening plates, concentration-response plates, and reformatted master stock plates (e.g., 384-well plates from 96-well plates). Integrated operations included centrifugation, unsealing/piercing, broadcast diluent addition, barcode print/application, compound transfer/mix via disposable pipette tips, and plate sealing. ALPS key features included instrument pooling for increased capacity or fail-over situations, programming constructs to associate one source plate to an array of replicate plates, and stacked collation of completed plates. Due to the hygroscopic nature of DMSO, ALPS was designed to operate within a 10% relativity humidity environment. The activities described are the collaborative efforts that contributed to the specification, build, delivery, and acceptance testing between Boehringer Ingelheim Pharmaceuticals, Inc. and the automation integration vendor, Thermo Scientific Laboratory Automation (Burlington, ON, Canada).

  18. Ultrasonic process for destruction of chlorinated organic compounds in aqueous solution

    International Nuclear Information System (INIS)

    Wu, Jiann M.; Huang, Hann S.

    1993-01-01

    Laboratory investigations of the ultrasonic process for destruction of low concentrations of carbon tetrachloride (CCl 4 ) into nonhazardous end products were carried out in a bench-scale batch reactor, equipped with a 600-W ultrasonic power supply. Process parameters studied included irradiation time, concentration, steady-state operating temperature, pH, and the intensity of applied ultrasonic-wave energy. High destruction efficiencies of greater than 99% were achieved through this process, and the irradiation time and the intensity of applied energy were identified to be the most important process parameters. The irradiation time required for a given degree of destruction decreased with increasing intensity of the applied ultrasonic energy. In addition, a detailed chemical reaction mechanism for the destruction of CCl 4 in water was formulated. The agreement between the model and experimental results is generally good

  19. Processing and Characterization of a Polypropylene Biocomposite Compounded with Maleated and Acrylated Compatibilizers

    Directory of Open Access Journals (Sweden)

    Brent A. Nerenz

    2012-01-01

    Full Text Available Polypropylene (PP biocomposites containing 20 wt.% sunflower hull as a particulate reinforcement were compounded and tested under tensile, flexural, and impact loadings. The incorporation of the sunflower hull without compatibilizer resulted in diminished tensile strength and impact energy absorption but increased flexural strength and both tensile modulus and flexural modulus when compared to neat PP. Formulations containing three different chemical compatibilizers were tested to determine their effectiveness in improving the interfacial adhesion between the fiber surface and PP chains. Maleic anhydride grafted with PP (MA-g-PP achieved greater improvements in tensile strength but reduced impact strength in comparison to an acrylic-acid-grafted PP compatibilizer (AA-g-PP. The molecular weight, graft level, and the ability to affect strength, modulus, and absorbed impact energy were also investigated for the compatibilizers. A MA-g-PP having high molecular weight and low graft level was most effective in improving the investigated properties of a sunflower hull-reinforced polypropylene biocomposite.

  20. Supercritical Carbon Dioxide Extraction of Bioactive Compounds from Ampelopsis grossedentata Stems: Process Optimization and Antioxidant Activity

    Directory of Open Access Journals (Sweden)

    Da Sun

    2011-10-01

    Full Text Available Supercritical carbon dioxide (SC-CO2 extraction of bioactive compounds including flavonoids and phenolics from Ampelopsis grossedentata stems was carried out. Extraction parameters such as pressure, temperature, dynamic time and modifier, were optimized using an orthogonal array design of L9 (34, and antioxidant activities of the extracts were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH free radical scavenging assay and ferrous ion chelating (FIC assay. The best conditions obtained for SC-CO2 extraction of flavonoids was 250 bar, 40 °C, 50 min, and with a modifier of methanol/ethanol (1:3, v/v, and that for phenolics extraction was 250 bar, 40 °C, 50 min, and with a modifier of methanol/ethanol (1:1, v/v. Meantime, flavonoids and phenolics were found to be mainly responsible for the DPPH scavenging activity of the extracts, but not for the chelating activity on ferrous ion according to Pearson correlation analysis. Furthermore, several unreported flavonoids such as apigenin, vitexin, luteolin, etc., have been detected in the extracts from A. grossedentata stems.

  1. Effect of different types of processing on the total phenolic compound content, antioxidant capacity, and saponin content of Chenopodium quinoa Willd grains.

    Science.gov (United States)

    Nickel, Júlia; Spanier, Luciana Pio; Botelho, Fabiana Torma; Gularte, Márcia Arocha; Helbig, Elizabete

    2016-10-15

    The effects of five processing forms on the content of phenolic compounds, antioxidant capacity, and saponin content in quinoa grains were evaluated. The processes included washing, washing followed by hydration, cooking (with or without pressure), and toasting. The highest content of phenolic compounds was obtained after cooking under pressure; however, these compounds also increased with grain washing. The toasting process caused the greatest loss. The antioxidant capacity of the grains was similarly affected by the processing techniques. According to the amount of saponins, the grains were classified as bitter. Washing caused a reduction in these compounds, but the levels remained unchanged after cooking (with and without) pressure and toasting; however, they significantly increased after hydration. Cooking, especially with pressure, had greater effects than the other processes, and potentiated the functional properties of quinoa grains. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Stability of arsenic compounds in seafood samples during processing and storage by freezing

    DEFF Research Database (Denmark)

    Dahl, Lisbeth; Molin, Marianne; Amlund, Heidi

    2010-01-01

    was observed after processing or after storage by freezing. The content of tetramethylarsonium ion was generally low in all samples types, but increased significantly in all fried samples of both fresh and frozen seafood. Upon storage by freezing, the arsenobetaine content was reduced significantly, but only...

  3. Cyclic thermochemical process for producing hydrogen using cerium-titanium compounds

    Science.gov (United States)

    Bamberger, C.E.

    A thermochemical cyclic process for producing hydrogen employs the reaction between ceric oxide and titanium dioxide to form cerium titanate and oxygen. The titanate is treated with an alkali metal hydroxide to give hydrogen, ceric oxide, an alkali metal titanate and water. Alkali metal titanate and water are boiled to give titanium dioxide which, along with ceric oxide, is recycled.

  4. Selective oxidation of organic compounds in waste water by ozone-based oxidation processes

    NARCIS (Netherlands)

    Boncz, M.A.

    2002-01-01

    For many different types of waste water, treatment systems have been implemented in the past decades. Waste water treatment is usually performed by biological processes, either aerobic or anaerobic, complemented with physical / chemical post treatment techniques.

  5. [Characteristics of volatile organic compounds (VOCs) emission from electronic products processing and manufacturing factory].

    Science.gov (United States)

    Cui, Ru; Ma, Yong-Liang

    2013-12-01

    Based on the EPA method T0-11 and 14/15 for measurement of toxic organics in air samples, fast VOCs detector, Summa canister and DNPH absorbent were used to determine the VOCs concentrations and the compositions in the ambient air of the workshops for different processes as well as the emission concentration in the exhaust gas. In all processes that involved VOCs release, concentrations of total VOCs in the workshops were 0.1-0.5 mg x m(-3), 1.5-2.5 mg x m(-3) and 20-200 mg x m(-3) for casting, cutting and painting respectively. Main compositions of VOCs in those workshops were alkanes, eneynes, aromatics, ketones, esters and ethers, totally over 20 different species. The main compositions in painting workshop were aromatics and ketones, among which the concentration of benzene was 0.02-0.34 mg x m(-3), toluene was 0.24-3.35 mg x m(-3), ethyl benzene was 0.04-1.33 mg x m(-3), p-xylene was 0.13-0.96 mg x m(-3), m-xylene was 0.02-1.18 mg x m(-3), acetone was 0.29-15.77 mg x m(-3), 2-butanone was 0.06-22.88 mg x m(-3), cyclohexene was 0.02-25.79 mg x m(-3), and methyl isobutyl ketone was 0-21.29 mg x m(-3). The VOCs emission from painting process was about 14 t x a(-1) for one single manufacturing line, and 840 t x a(-1) for the whole factory. According to the work flows and product processes, the solvent used during painting process was the main source of VOCs emission, and the exhaust gas was the main emission point.

  6. Development of sodium disposal technology. Experiment of sodium compound solidification process

    International Nuclear Information System (INIS)

    Matsumoto, Toshiyuki; Ohura, Masato; Yatoh, Yasuo

    2007-07-01

    A large amount of sodium containing radioactive waste will come up at the time of final shutdown/decommission of FBR plant. The radioactive waste is managed as solid state material in a closed can in Japan. As for the sodium, there is no established method to convert the radioactive sodium to solid waste. Further, the sodium is highly reactive. Thus, it is recommended to convert the sodium to a stable substance before the solidification process. One of the stabilizing methods is conversion of sodium into sodium hydroxide solution. These stabilization and solidification processes should be safe, economical, and efficient. In order to develop such sodium disposal technology, nonradioactive sodium was used and a basic experiment was performed. Waste-fluid Slag Solidification method was employed as the solidification process of sodium hydroxide solution. Experimental parameters were mixing ratio of the sodium hydroxide and the slag solidification material, temperature and concentration of the sodium hydroxide. The best parameters were obtained to achieve the maximum filling ratio of the sodium hydroxide under a condition of enough high compressive strength of the solidified waste. In a beaker level test, the solidified waste was kept in a long term and it was shown that there was no change of appearance, density, and also the compressive strength was kept at a target value. In a real scale test, homogeneous profiles of the density and the compressive strength were obtained. The compressive strength was higher than the target value. It was shown that the Waste-fluid Slag Solidification method can be applied to the solidification process of the sodium hydroxide solution, which was produced by the stabilization process. (author)

  7. Changes in Phenolic Compounds and Phytotoxicity of the Spanish-Style Green Olive Processing Wastewaters by Aspergillus niger B60.

    Science.gov (United States)

    Papadaki, Eugenia; Tsimidou, Maria Z; Mantzouridou, Fani Th

    2018-05-16

    This study systematically investigated the degradation kinetics and changes in the composition of phenolic compounds in Spanish-style Chalkidiki green olive processing wastewaters (TOPWs) during treatment using Aspergillus niger B60. The fungal growth and phenol degradation kinetics were described sufficiently by the Logistic and Edward models, respectively. The maximum specific growth rate (2.626 1/d) and the maximum degradation rate (0.690 1/h) were observed at 1500 mg/L of total polar phenols, indicating the applicability of the process in TOPWs with a high concentration of phenolic compounds. Hydroxytyrosol and the other simple phenols were depleted after 3-8 days. The newly formed secoiridoid derivatives identified by HPLC-DAD-FLD and LC-MS are likely produced by oleoside and oleuropein aglycon via the action of fungal β-glucosidase and esterase. The treated streams were found to be less phytotoxic with reduced chemical oxygen demand by up to 76%. Findings will provide useful information for the subsequent treatment of residual contaminants.

  8. Exposure assessment and engineering control strategies for airborne nanoparticles: an application to emissions from nanocomposite compounding processes

    International Nuclear Information System (INIS)

    Tsai, Candace S.-J.; White, David; Rodriguez, Henoc; Munoz, Christian E.; Huang, Cheng-Yu; Tsai, Chuen-Jinn; Barry, Carol; Ellenbecker, Michael J.

    2012-01-01

    In this study, nanoalumina and nanoclay particles were compounded separately with ethylene vinyl acetate (EVA) polymer to produce nanocomposites using a twin-screw extruder to investigate exposure and effective controls. Nanoparticle exposures from compounding processes were elevated under some circumstances and were affected by many factors including inadequate ventilation, surrounding air flow, feeder type, feeding method, and nanoparticle type. Engineering controls such as improved ventilation and enclosure of releasing sources were applied to the process equipment to evaluate the effectiveness of control. The nanoparticle loading device was modified by installing a ventilated enclosure surrounding the loading chamber. Exposures were studied using designed controls for comparison which include three scenarios: (1) no isolation; (2) enclosed sources; and (3) enclosed sources and improved ventilation. Particle number concentrations for diameters from 5 to 20,000 nm measured by the Fast Mobility Particle Sizer and aerodynamic particle sizer were studied. Aerosol particles were sampled on transmission electron microscope grids to characterize particle composition and morphology. Measurements and samples were taken at the near- and far-field areas relative to releasing sources. Airborne particle concentrations were reduced significantly when using the feeder enclosure, and the concentrations were below the baseline when two sources were enclosed, and the ventilation was improved when using either nanoalumina or nanoclay as fillers.

  9. Stochastic interest model driven by compound Poisson process andBrownian motion with applications in life contingencies

    Directory of Open Access Journals (Sweden)

    Shilong Li

    2018-03-01

    Full Text Available In this paper, we introduce a class of stochastic interest model driven by a compoundPoisson process and a Brownian motion, in which the jumping times of force of interest obeyscompound Poisson process and the continuous tiny fluctuations are described by Brownian motion, andthe adjustment in each jump of interest force is assumed to be random. Based on the proposed interestmodel, we discuss the expected discounted function, the validity of the model and actuarial presentvalues of life annuities and life insurances under different parameters and distribution settings. Ournumerical results show actuarial values could be sensitive to the parameters and distribution settings,which shows the importance of introducing this kind interest model.

  10. Attachment to a mass spectrometer for studying the processes of semiconductor compound deposition from a gaseous phase

    International Nuclear Information System (INIS)

    Belousov, V.I.; Zhuravlev, G.I.; Popenko, N.I.; Novozhilov, A.F.; Matveev, I.V.; Murav'ev, V.V.

    1984-01-01

    An attachment to the mass spectrometer for studying the processes of semiconductor compounds deposition from a gaseous phase at the pressure of 1x10 5 Pa and the temperature of 400-1300 K is described. The attachment consists of the Neer ion source with ionization section cooled upto the temperature of liquid nitrogen, a two-zone vacuum furnace, and a quartz epitaxy reactor of the horzontal type.The attachment is equipped with the systems of process gas distribution in 5 flows and temperature stabilization. The rate of mass spectrum recording constitutes 2 mass/s at the resolution being equal to 1000 at the 10% level. The sensitivity at the steam-gas mixture components partial pressure determination constitutes 1x10 -4 Pa

  11. Fluorinated compounds in the uranium conversion process: risk analysis and proposition of pictograms

    International Nuclear Information System (INIS)

    Jeronimo, Adroaldo Clovis; Oliveira, Wagner dos Santos

    2012-01-01

    In the process of uranium hexafluoride production there are risks that must be taken into account since the time of completing the project chemist, in its conceptual stage, until to the stage of detailed design and are associated with the handling of chemicals, especially fluoride hydrogen and fluorine. This paper aims to address issues related to the prevention of risks related to industrial safety and health and the environment, considering the different stages of the uranium conversion. Take into account the safety warnings of the plant and, accordingly, make the proposition of pictograms adequate to alert operators of care to be taken during the proposition of pictograms adequate to alert operators of care to be taken during the conduct of these chemical processes. (author)

  12. Process for the restoration of solids contaminated with hydrocarbons and heavy organic compounds

    International Nuclear Information System (INIS)

    Bala, G.A.; Thomas, C.P.; Jackson, J.D.; McMillin, R.A.

    1994-01-01

    Processes have been developed for the restoration of environments contaminated with hydrocarbons and heavy organics. The intended product is a field deployable materials handling system and phase separation process ranging in size from 1 yd 3 /hr to 50 yd 3 /hr for commercial application to environmental problems associated with the exploration, production, refining and transport of petroleum, petroleum products and organic chemicals. Effluents from contaminated sites will be clean solids (classified by size if appropriate), and the concentrated contaminant. The technology is based on biochemical solvation, liquid/liquid and liquid/solid extractions, materials classification, mechanical and hydraulic scrubbing, and phase separation of organic and aqueous phases. Fluid use is minimized through utilization of closed-loop (recycle) systems. Contaminants that are removed from the solid materials may be destroyed, disposed of using existing technologies, or used on-site for cogeneration of /power for plant operations. Additionally, if the contaminant is a valued product, the material may be recovered for application or sale. Clean solid material is not sterilized and may be returned to normal agricultural, commercial, residential or recreational use in most instances

  13. Zinc oxide nanostructures and its nano-compounds for efficient visible light photo-catalytic processes

    Science.gov (United States)

    Adam, Rania E.; Alnoor, Hatim; Elhag, Sami; Nur, Omer; Willander, Magnus

    2017-02-01

    Zinc oxide (ZnO) in its nanostructure form is a promising material for visible light emission/absorption and utilization in different energy efficient photocatalytic processes. We will first present our recent results on the effect of varying the molar ratio of the synthesis nutrients on visible light emission. Further we will use the optimized conditions from the molar ration experiments to vary the synthesis processing parameters like stirring time etc. and the effect of all these parameters in order to optimize the efficiency and control the emission spectrum are investigated using different complementary techniques. Cathodoluminescence (CL) is combined with photoluminescence (PL) and electroluminescence (EL) as the techniques to investigate and optimizes visible light emission from ZnO/GaN light emitting diodes. We will then show and discuss our recent finding of the use of high quality ZnO nanoparticles (NPs) for efficient photo-degradation of toxic dyes using the visible spectra, namely with a wavelength up to 800 nm. In the end, we show how ZnO nanorods (NRs) are used as the first template to be transferred to bismuth zinc vanadate (BiZn2VO6). The BiZn2VO6 is then used to demonstrate efficient and cost effective hydrogen production through photoelectrochemical water splitting using solar radiation.

  14. Accumulation of organic compounds leached from plastic materials used in biopharmaceutical process containers.

    Science.gov (United States)

    Jenke, Dennis R; Zietlow, David; Garber, Mary Jo; Sadain, Salma; Reiber, Duane; Terbush, William

    2007-01-01

    Plastic materials are widely used in medical items, such as solution containers, transfusion sets, transfer tubing, and devices. An emerging trend in the biotechnology industry is the utilization of plastic containers to prepare, transport, and store an assortment of solutions including buffers, media, and in-process and finished product. The direct contact of such containers with the product at one or more points in its lifetime raises the possibility that container leachables may accumulate in the finished product. The interaction between several commercially available container materials and numerous model test solutions (representative of buffers and media used in biopharmaceutical applications) was investigated. This paper summarizes the identification of leachables associated with the container materials and documents the levels to which targeted leachables accumulate in the test solutions under defined storage conditions.

  15. Mass-Spectrometric Studies of Catalytic Chemical Vapor Deposition Processes of Organic Silicon Compounds Containing Nitrogen

    Science.gov (United States)

    Morimoto, Takashi; Ansari, S. G.; Yoneyama, Koji; Nakajima, Teppei; Masuda, Atsushi; Matsumura, Hideki; Nakamura, Megumi; Umemoto, Hironobu

    2006-02-01

    The mechanism of catalytic chemical vapor deposition (Cat-CVD) processes for hexamethyldisilazane (HMDS) and trisdimethylaminosilane (TDMAS), which are used as source gases to prepare SiNx or SiCxNy films, was studied using three different mass spectrometric techniques: ionization by Li+ ion attachment, vacuum-ultraviolet radiation and electron impact. The results for HMDS show that Si-N bonds dissociate selectively, although Si-C bonds are weaker, and (CH3)3SiNH should be one of the main precursors of deposited films. This decomposition mechanism did not change when NH3 was introduced, but the decomposition efficiency was slightly increased. Similar results were obtained for TDMAS.

  16. Transformation of polyfluorinated compounds in natural waters by advanced oxidation processes.

    Science.gov (United States)

    Anumol, Tarun; Dagnino, Sonia; Vandervort, Darcy R; Snyder, Shane A

    2016-02-01

    The presence of perfluorocarboxylic acids (PFCAs) in source and finished drinking waters is a concern with studies showing bioaccumulation and adverse toxicological effects in wildlife and potentially humans. Per/Polyfluoroalkyl substances (PFAS) such as fluorotelomer alcohols have been identified as precursors for PFCAs in biological pathways. In this study, we investigated the fate of 6:2 and 8:2 homologues of the fluorotelomer unsaturated carboxylic acids (FTUCAs) during advanced oxidation process (AOPs). Results showed 6:2 FTUCA and 8:2 FTUCA transformed into 6-C PFCA (PFHxA) and 8-C PFCA (PFOA) respectively with very little other PFCA formation for all AOPs. The degradation of 6:2 FTUCA and 8:2 FTUCA was greater in the GW compared to SW for the ozone processes but similar for UV/H2O2. The formation of n-C PFCA followed O3>O3/H2O2 at same dose and UV/H2O2 had much lower formation at the doses tested. Non-targeted analysis with the LC-MS-qTOF indicated the production of other PFCAs which contribute to the total mass balance, although no intermediate product was discovered indicating a rapid and direct transformation from the FTUCAs to the PFCAs and/or significant volatilization of intermediates. With the use of AOPs essential to water reuse treatment schemes, this work raises concerns over the risk of potential formation of PFCAs in the treatment and their adverse health effects in finished drinking water. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. The content of polyphenolic compounds in cocoa beans (Theobroma cacao L.), depending on variety, growing region, and processing operations: a review.

    Science.gov (United States)

    Oracz, Joanna; Zyzelewicz, Dorota; Nebesny, Ewa

    2015-01-01

    Polyphenols form the largest group of compounds among natural antioxidants, which largely affect the overall antioxidant and anti-free radical activity of cocoa beans. The qualitative and quantitative composition of individual fractions of polyphenolic compounds, even within one species, is very diverse and depends on many factors, mainly on the area of cocoa trees cultivation, bean maturity, climatic conditions during growth, and the harvest season and storage time after harvest. Thermal processing of cocoa beans and cocoa derivative products at relatively high temperatures may in addition to favorable physicochemical, microbiological, and organoleptic changes result in a decrease of polyphenols concentration. Technological processing of cocoa beans negatively affects the content of polyphenolic compounds.

  18. Effects-Directed Analysis of Dissolved Organic Compounds in Oil Sands Process-Affected Water.

    Science.gov (United States)

    Morandi, Garrett D; Wiseman, Steve B; Pereira, Alberto; Mankidy, Rishikesh; Gault, Ian G M; Martin, Jonathan W; Giesy, John P

    2015-10-20

    Acute toxicity of oil sands process-affected water (OSPW) is caused by its complex mixture of bitumen-derived organics, but the specific chemical classes that are most toxic have not been demonstrated. Here, effects-directed analysis was used to determine the most acutely toxic chemical classes in OSPW collected from the world's first oil sands end-pit lake. Three sequential rounds of fractionation, chemical analysis (ultrahigh resolution mass spectrometry), and acute toxicity testing (96 h fathead minnow embryo lethality and 15 min Microtox bioassay) were conducted. Following primary fractionation, toxicity was primarily attributable to the neutral extractable fraction (F1-NE), containing 27% of original organics mass. In secondary fractionation, F1-NE was subfractionated by alkaline water washing, and toxicity was primarily isolated to the ionizable fraction (F2-NE2), containing 18.5% of the original organic mass. In the final round, chromatographic subfractionation of F2-NE2 resulted in two toxic fractions, with the most potent (F3-NE2a, 11% of original organic mass) containing predominantly naphthenic acids (O2(-)). The less-toxic fraction (F3-NE2b, 8% of original organic mass) contained predominantly nonacid species (O(+), O2(+), SO(+), NO(+)). Evidence supports naphthenic acids as among the most acutely toxic chemical classes in OSPW, but nonacidic species also contribute to acute toxicity of OSPW.

  19. Effects of sugar concentration processes in grapes and wine aging on aroma compounds of sweet wines—a review.

    Science.gov (United States)

    Reboredo-Rodríguez, Patricia; González-Barreiro, Carmen; Rial-Otero, Raquel; Cancho-Grande, Beatriz; Simal-Gándara, Jesús

    2015-01-01

    Dessert sweet wines from Europe and North America are described in this review from two points of view: both their aroma profile and also their sensorial description. There are growing literature data about the chemical composition and sensory properties of these wines. Wines were grouped according to the production method (concentration of sugars in grapes) and to the aging process of wine (oxidative, biological, or a combination of both and aging in the bottle). It was found that wines natively sweets and wines fortified with liquors differ in their volatile compounds. Sensory properties of these wines include those of dried fruit (raisins), red berries, honey, chocolate and vanilla, which is contributing to their growing sales. However, there is still a need for scientific research on the understanding of the mechanisms for wine flavor enhancement.

  20. A Survey of Electron Impact Cross-Sections for Halogens and Halogen Compounds of Interest to Plasma Processing

    Science.gov (United States)

    Sharma, S. P.; Rao, M. V. V. S.; Arnold, James O. (Technical Monitor)

    1998-01-01

    Published electron impact cross section data on halogens Cl2, F2, and halogen containing compounds such as Cx Fy, HCl, Cx Cly Fz are reviewed and critically evaluated based on the information provided by various researchers. The present work reports data on electron impact excitation, ionization, dissociation, electron attachment, electron detachment, and photo detachment. Elastic scattering cross sections and data on bulk properties such as diffusion coefficients in various background gases are also evaluated. Since some of the cross sectional data is derived from indirect measurements such as drift velocity, care has been taken to reconcile the differences among the reported data with due attention to the measurement technique. In conclusion, the processes with no or very limited amount of data and questionable set of data are identified and recommendation for further research direction is made.

  1. Reactive transport modeling of processes controlling the distribution and natural attenuation of phenolic compounds in a deep sandstone aquifer

    Science.gov (United States)

    Mayer, K. U.; Benner, S. G.; Frind, E. O.; Thornton, S. F.; Lerner, D. N.

    2001-12-01

    Reactive solute transport modeling was utilized to evaluate the potential for natural attenuation of a contaminant plume containing phenolic compounds at a chemical producer in the West Midlands, UK. The reactive transport simulations consider microbially mediated biodegradation of the phenolic compounds (phenols, cresols, and xylenols) by multiple electron acceptors. Inorganic reactions including hydrolysis, aqueous complexation, dissolution of primary minerals, formation of secondary mineral phases, and ion exchange are considered. One-dimensional (1D) and three-dimensional (3D) simulations were conducted. Mass balance calculations indicate that biodegradation in the saturated zone has degraded approximately 1-5% of the organic contaminant plume over a time period of 47 years. Simulations indicate that denitrification is the most significant degradation process, accounting for approximately 50% of the organic contaminant removal, followed by sulfate reduction and fermentation reactions, each contributing 15-20%. Aerobic respiration accounts for less than 10% of the observed contaminant removal in the saturated zone. Although concentrations of Fe(III) and Mn(IV) mineral phases are high in the aquifer sediment, reductive dissolution is limited, producing only 5% of the observed mass loss. Mass balance calculations suggest that no more than 20-25% of the observed total inorganic carbon (TIC) was generated from biodegradation reactions in the saturated zone. Simulations indicate that aerobic biodegradation in the unsaturated zone, before the contaminant entered the aquifer, may have produced the majority of the TIC observed in the plume. Because long-term degradation is limited to processes within the saturated zone, use of observed TIC concentrations to predict the future natural attenuation may overestimate contaminant degradation by a factor of 4-5.

  2. Antioxidant activity and polyphenolic compound stability of lentil-orange peel powder blend in an extrusion process.

    Science.gov (United States)

    Rathod, Rahul P; Annapure, Uday S

    2017-03-01

    Lentil contains substantial amount of protein, carbohydrate, fibre and other nutrients and orange peels powder rich in carbohydrate and fiber content The present study was aimed to investigate the effects of extrusion processing parameter on the level of total phenolic content (TPC), total flavonoid content (TFC), total tannin content and antioxidant activity of lentil-orange peel powder blend, also to investigate the possibility of blend as a candidate for production of protein rich extruded product by using response surface methodology. It was observed that, the physicochemical properties and sensory characteristics of lentil-orange peel based extrudate were highly dependent on process variables. The blend of lentil and orange peel powder has a huge potential for extrusion to produce ready-to-eat extruded with good acceptance. The overall best quality product was optimized and obtained at 16% moisture, 150 °C die temperature and 200 rpm screw speed. Extrusion process increased nutritional value of extruded product with TPC and TFC of 70.4 and 67.62% respectively and antioxidant activity of 60.6%. It showed higher stability at 150 °C with intermediate feed moisture content and despite the use of high temperatures in the extrusion-cooking is possible to minimize the loss of bioactive compounds to achieve products. Thus, results indicated that blend of lentil and orange peel may be used as raw material for the production of extruded snacks with great nutritional value.

  3. Post processing of protein-compound docking for fragment-based drug discovery (FBDD): in-silico structure-based drug screening and ligand-binding pose prediction.

    Science.gov (United States)

    Fukunishi, Yoshifumi

    2010-01-01

    For fragment-based drug development, both hit (active) compound prediction and docking-pose (protein-ligand complex structure) prediction of the hit compound are important, since chemical modification (fragment linking, fragment evolution) subsequent to the hit discovery must be performed based on the protein-ligand complex structure. However, the naïve protein-compound docking calculation shows poor accuracy in terms of docking-pose prediction. Thus, post-processing of the protein-compound docking is necessary. Recently, several methods for the post-processing of protein-compound docking have been proposed. In FBDD, the compounds are smaller than those for conventional drug screening. This makes it difficult to perform the protein-compound docking calculation. A method to avoid this problem has been reported. Protein-ligand binding free energy estimation is useful to reduce the procedures involved in the chemical modification of the hit fragment. Several prediction methods have been proposed for high-accuracy estimation of protein-ligand binding free energy. This paper summarizes the various computational methods proposed for docking-pose prediction and their usefulness in FBDD.

  4. Study of the oxidation process of disperse Fe-C containing waste in order to obtain graphite intercalation compounds

    Directory of Open Access Journals (Sweden)

    Володимир Олександрович Маслов

    2016-11-01

    Full Text Available Graphite processing into intercalation compounds followed by thermoshock heating is known in literature. The result is an ultra-light dispersed graphite (thermographenit used in lots of industries. Graphite intercalation compounds are formed as a result of the introduction of atomic and molecular layers of different chemical particles between the layers of graphite plates. The object of this work is to obtain a new material by intercalation of graphite followed by thermoshock heating, which could be used for products protecting biological and technical facilities from electromagnetic and thermal radiation. In the present work the parameters of oxidation and of graphite thermoshock expansion in order to obtain graphite intercalation compounds and thermographenit were investigated. The experiments were performed under laboratory non-isothermal conditions. Graphite GAK-2 obtained from metallurgical wastes was used. First the fraction of +0,16 mm with the ash content of 0,3% was extracted by scattering. The oxidation of graphite was carried out by potassium bichromate dissolved in concentrated sulphuric acid. The original sample of graphite was mixed with finely grounded potassium bichromate. Then this mass was poured over with 98% concentrated sulphuric acid when being actively stirred and kept. Then the capacitance for oxidation was filled with distilled water. Decantation was carried out until pH=7 in the waste water was got. Separation of the oxidized graphite from the main mass of water was carried out by means of a suction filter until pH=7 was got. Experiments were performed at different ratios of potassium bichromate, sulphuric acid and graphite. The optimum ratio of the components (sulphuric acid : (dichromate of potash : (graphite = 2,8 : 0,15 : 1 was found. The oxidation time was 4–5 minutes. The oxidized graphite turned into thermographenit with bulk density of 2,7–9,5 kg/m3.upon subsequent heating up to 1000oC within the regime of

  5. Secondary electronic processes and the structure of X-ray photoelectron spectra of lanthanides in oxygen-containing compounds

    International Nuclear Information System (INIS)

    Teterin, Yu.A.; Teterin, A.Yu.; Lebedev, A.M.; Ivanov, K.E.

    2004-01-01

    X-ray photoelectron spectra of lanthanide compounds in the binding energy range 0-1250 eV beside the spin-orbitally split doublets exhibit fine structure. In particular, in the low-energy spectral range 0-50 eV such structure appears most likely due to the formation of the inner (IVMO) and outer (OVMO) valence molecular orbitals. The many-body perturbation shows up in the spectra of all the studied electronic shells but with different probabilities, while the multiplet splitting and dynamic effect in the spectra of just some inner shells. The present work studies the X-ray photoelectron spectral structure of lanthanide (La-Lu except for Pm) oxides and orthoniobates due to the secondary electronic processes accompanying the photoemission from the inner shells: many-body perturbation and dynamic effect. As a result, for example, the relative intensity of the line due to the many-body perturbation (shake-up process) with ΔE sat ∼4 eV for LaNbO 4 was found to decrease with decreasing of the binding energy of the inner electrons from 0.72 (E b for La 3d 5/2 =834.8 eV) to 0.28 (E b for La 4d 5/2 =102.9 eV). The full-width at half-maximum of the Ln 3d 5/2 line of lanthanide oxides and orthoniobates decreases as the atomic number Z of lanthanide grows in the range 58≤Z≤67 to the middle of the lanthanide row, and then increases. This agrees with the fact that for the beginning of the lanthanide row the Ln 3d 5/2 photoemission is accompanied by the shake-up process, while for the second half of the row--by the shake-down. It is important to note that it is connected with the Ln 4f binding energy change relative to the OVMO in compounds. The present work also confirms experimentally that the dynamic effect due to the gigantic Coster-Kronig transitions observed in the Ln 4p spectra takes place within the inner Ln 4p, 4d and outer Ln 4f shells with formation of the additional two-hole final state Ln 4p 6 4d 8 4f n+1 . The influence of the chemical environment on the Ln 4

  6. Fractionation of yeast extract by nanofiltration process to assess key compounds involved in CHO cell culture improvement.

    Science.gov (United States)

    Mosser, Mathilde; Kapel, Romain; Chevalot, Isabelle; Olmos, Eric; Marc, Ivan; Marc, Annie; Oriol, Eric

    2015-01-01

    Yeast extract (YE) is known to greatly enhance mammalian cell culture performances, but its undefined composition decreases process reliability. Accordingly, in the present study, the nature of YE compounds involved in the improvement of recombinant CHO cell growth and IgG production was investigated. First, the benefits of YE were verified, revealing that it increased maximal concentrations of viable cells and IgG up to 73 and 60%, respectively compared to a reference culture. Then, the analyses of YE composition highlighted the presence of molecules such as amino acids, vitamins, salts, nucleobase, and glucose that were contained in reference medium, while others including peptides, trehalose, polysaccharides, and nucleic acids were not. Consequently, YE was fractionated by a nanofiltration process to deeper evaluate its effects on CHO cell cultures. The YE molecules already contained in reference medium were mainly isolated in the permeate fraction together with trehalose and short peptides, while other molecules were concentrated in the retentate. Permeate, which was free of macromolecules, exhibited a similar positive effect than raw YE on maximal concentrations. Additional studies on cell energetic metabolism underlined that dipeptides and tripeptides in permeate were used as an efficient source of nitrogenous substrates. © 2015 American Institute of Chemical Engineers.

  7. Loadings of polynuclear aromatic compounds and metals to the Athabasca River watershed by oil sands mining and processing

    International Nuclear Information System (INIS)

    Hodson, P.V.

    2010-01-01

    The contribution of oil sands operations to pollution in the Athabasca River has not yet been determined. Wastes from oil sands processes include recycled water, sand, silt, clay, bitumen, and polycyclic aromatic compounds (PAC) and metals. Upgrading processes can also release significant quantities of PAC and heavy metals. This paper discussed a study in which PAC and metals in the snow pack and river water of the Athabasca watershed were assessed. The study showed that the oil sands industry is a significant source of contamination. The equivalent of 600 T of bitumen was observed at sites within 50 km of oil sands upgrading facilities. The strongest contamination signals occurred during the summer months, which suggested that the surface run-off of contaminated water was related to recent oil sands developments. Samples taken from tributaries in watersheds with little or no development indicated that increased concentrations of oil sands related contaminants were not caused by natural erosion. The contaminants may contribute to higher levels of mercury (Hg) and cadmium (Cd) in the flesh of fish and wildlife and increase toxicity to the embryos of spring-spawning fish.

  8. Synergic nature of dielectric relaxation process in the layered perovskite halide salts: The case of 1,3- diammoniumpropylenetetrabromocadmate compound

    Science.gov (United States)

    Staśkiewicz, Beata

    2018-06-01

    The negative thermal expansion (NTE) property was a prototype to discuss the origin of difference between classical Debye relaxation process and the non-Debye behavior in the layered perovskite halide salt of chemical formula NH3(CH2)3NH3CdBr4. The analysis has been taken by dielectric relaxation spectroscopy measurements in almost six decades in frequency 5 × 102 ≤ f(ω) ≤ 1.2 × 108 and in the temperature range 315 ≤ T(K) ≤ 390. It was shown that the investigated sample exhibit an antiferrodistortive nature of phase transition between two orthorhombic structural modifications i.e. Pnma (phase I) and Ima2 (phase II) at Tc1(I → II) = 326 K, leading from an antiferroelectric to a paraelectric phase. The involvement of an odd number of carbon atoms in the alkylammonium chains in dielectric properties of examined sample is proved. Higher structural modifications, i.e. Ima2 (phase II) and P21/m (phase III), have shown significant deviations from a regular circle on the Cole-Cole diagram. Presented experimental observations are essentially important for the theoretical explanation of relaxation processes in analyzed organic - inorganic compound crystallizing in a perovskite-like topology and may provide new perspective on the fundamental aspect of relaxation response in "diammonium" series.

  9. Chitosan microparticles: influence of the gelation process on the release profile and oral bioavailability of albendazole, a class II compound.

    Science.gov (United States)

    Piccirilli, Gisela N; García, Agustina; Leonardi, Darío; Mamprin, María E; Bolmaro, Raúl E; Salomón, Claudio J; Lamas, María C

    2014-11-01

    Encapsulation of albendazole, a class II compound, into polymeric microparticles based on chitosan-sodium lauryl sulfate was investigated as a strategy to improve drug dissolution and oral bioavailability. The microparticles were prepared by spray drying technique and further characterized by means of X-ray powder diffractometry, infrared spectroscopy and scanning electron microscopy. The formation of a novel polymeric structure between chitosan and sodium lauryl sulfate, after the internal or external gelation process, was observed by infrared spectroscopy. The efficiency of encapsulation was found to be between 60 and 85% depending on the internal or external gelation process. Almost spherically spray dried microparticles were observed using scanning electron microscopy. In vitro dissolution results indicated that the microparticles prepared by internal gelation released 8% of the drug within 30 min, while the microparticles prepared by external gelation released 67% within 30 min. It was observed that the AUC and Cmax values of ABZ from microparticles were greatly improved, in comparison with the non-encapsulated drug. In conclusion, the release properties and oral bioavailability of albendazole were greatly improved by using spraydried chitosan-sodium lauryl sulphate microparticles.

  10. Linde Rectiscol{reg_sign} process. The most economic and experienced wash process for removal of sulfur compounds and CO{sub 2} from gasification gases

    Energy Technology Data Exchange (ETDEWEB)

    Kaballo, H.-P.; Kerestceciogly, U. [Linde AG, Hoellriegelskreuth (Germany). Linde Engineering Division

    2006-07-01

    The Recitsol{reg_sign} wash process is a well-proven process for the removal of H{sub 2}S/COS and CO{sub 2} from coal, asphalt, pitch or oil derived synthesis gas. It is a physical gas wash system using methanol as solvent at operating temperatures below water freezing point, to produce a synthesis gas with less than 0.1 vppm of total sulfur. The CO{sub 2} content can be adjusted in a range from several mol-percent down to a few ppm, as is required by the specified application. Its main advantages are the use of cheap and readily available methanol as solvent, the very flexible process configuration, and rather low utility consumption figures compared with other wash processes, like PEGE based process or chemical washes. A modern concept of a Rectisol{reg_sign} unit is described, to treat shifted and un-shifted gases in just one plant: shifted gas was used for hydrotreating in a refinery. Unshifted gas was used as fuel gas for power generation in an IGCC. CO{sub 2} of the unshifted feed gas was removed only partly, because the remaining CO{sub 2} was fed as inert gas together with the fuel gas to an IGCC. All sulfur compounds of both feed gases were concentrated in one single stream with a high H{sub 2}S concentration. Impurities like NH{sub 3}, HCN or metal carbonyls were eliminated nearly quantitatively. 4 refs., 4 figs., 3 tabs.

  11. Differentiation of the molecular structure of nitro compounds as the basis for simulation of their thermal destruction processes

    Energy Technology Data Exchange (ETDEWEB)

    Korolev, V L; Pivina, Tatyana S; Sheremetev, Aleksei B [N.D.Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow (Russian Federation); Porollo, A A [University of Cincinnati, Cincinnati (United States); Petukhova, T V; Ivshin, Viktor P [Mari State University, Yoshkar-Ola (Russian Federation)

    2009-10-31

    Data on the experimental and theoretical studies of thermal decomposition of C- and N-nitro compounds of aliphatic, alicyclic, aromatic and heteroaromatic compounds, which formed the grounds for the development of ab initio approach to the prediction of the mechanisms of thermolysis of energetic compounds, are described systematically. The relationships between the structures and thermolysis mechanisms of compounds based on differentiation of the structural fragments depending on the functional surrounding of nitro groups are identified. Using the RRN (Recombination Reaction Network) strategy and original CASB (Computer Assisted Structure Building) software, full reaction mechanisms for the thermal destruction of nitro compounds at different thermal decomposition levels (including extensive ones) are simulated. The full set of possible mechanisms of thermal decomposition of 38 chemically different nitro compounds is presented

  12. A biorefinery concept for simultaneous recovery of cellulosic ethanol and phenolic compounds from oil palm fronds: Process optimization

    International Nuclear Information System (INIS)

    Ofori-Boateng, Cynthia; Lee, Keat Teong; Saad, Bahruddin

    2014-01-01

    Highlights: • Biorefinery concept for simultaneous recovery of cellulose and phenolic compounds. • Sono-assisted organosolv/H 2 O 2 pretreatment was used to isolate palm fronds cellulose. • Optimum conditions for pretreatment: 60 °C, 40 min, 1:20 g/ml, 3% NaOH concentration. • Optimum conditions yielded 55.3% cellulose, 20.1 g/l glucose and 0.769 g/g ethanol. • Pretreatment liquor contained 4.691 mg GAE/g phenolics. - Abstract: In this study, process optimization of an ultrasonic-assisted organosolv/liquid oxidative pretreatment (SOP) of oil palm fronds (OPFs) for the simultaneous recovery of cellulose, bioethanol and biochemicals (i.e. phenolic compounds) in a biorefinery concept was carried out. The effects of time (30–60 min.), temperature (40–80 °C), NaOH concentration (1–5%) and sample:solvent ratio (1:10–1:50 g/ml) on cellulose content, bioethanol yield and total phenolics contents (TPC) after SOP were investigated. At optimum conditions of pretreatment (i.e. 60 °C, 40 min, 3% w/v aq. NaOH and 1:20 g/ml sample to solvent ratio), the recovered cellulose (55.30%) which served as substrate for enzymatic hydrolysis and subsequent fermentation yielded about 20.1 g/l glucose, 11.3 g/l xylose and 9.3 g/l bioethanol (yield of 0.769 g/g). The pretreatment liquor (mostly regarded as wastes) obtained at the optimum pretreatment conditions contained about 4.691 mg gallic acid equivalent (GAE)/g OPFs of TPC, 0.297 mg vanillic acid (VA)/g OPFs, 1.591 mg gallic acid (GA)/g OPFs and 0.331 mg quercetin (QU)/g OPFs. The pretreatment liquor was again analyzed to possess high antiradical scavenging activity (about 97.2%) compared to the synthetic antioxidant, 3,5-di-tert-butyl-4-hydroxytoluene (BHT) (80.7%) at 100 ppm. Thus one sustainable way of managing wastes in biorefinery is the recovery of multi-bioproducts (e.g. bioethanol and biochemicals) during the pretreatment process

  13. Emission characteristics of nitrogen- and sulfur-containing odorous compounds during different sewage sludge chemical conditioning processes

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Huan [State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074 (China); School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Luo, Guang-Qian; Hu, Hong-Yun [State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074 (China); Zhang, Qiang; Yang, Jia-Kuan [School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Yao, Hong, E-mail: hyao@hust.edu.cn [State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer NH{sub 3}, SO{sub 2}, H{sub 2}S and COS are emitted during different sludge conditioning processes. Black-Right-Pointing-Pointer H{sub 2}S and SO{sub 2} generation increase in the acidic environment created by H{sub 2}SO{sub 4}. Black-Right-Pointing-Pointer Fenton peroxidation facilitates the formation of COS. Black-Right-Pointing-Pointer CaO can reduce sulfur-containing gases emission via generation of calcium sulfate. Black-Right-Pointing-Pointer CaO leads to the conversion of free ammonia or protonated amine to volatile NH{sub 3}. - Abstract: Chemical conditioners are often used to enhance sewage sludge dewaterability through altering sludge properties and flocs structure, both affect odorous compounds emissions not only during sludge conditioning but also in subsequent sludge disposal. This study was to investigate emission characteristics of ammonia (NH{sub 3}), sulfur dioxide (SO{sub 2}), hydrogen sulfide (H{sub 2}S) and carbonyl sulfide (COS) generated from sewage sludge conditioned by three representative conditioners, i.e., organic polymers, iron salts and skeleton builders, F-S (Fenton's reagent and skeleton builders) composite conditioner. The results demonstrate that polyacrylamide (PAM) has an insignificant effect on emission characteristics of nitrogen- and sulfur-containing odorous compounds, because the properties, sulfur and nitrogen speciations are similar in PAM-conditioned sludge and raw sludge (RS). Significant increases of SO{sub 2} and H{sub 2}S emissions in the H{sub 2}SO{sub 4} conditioning process were observed due to the accelerated decomposition of sulfur-containing amino acids in acidic environment. Fenton peroxidation facilitates the formation of COS. CaO can reduce sulfur-containing gases emission via generation of calcium sulfate. However, under strong alkaline conditions, free ammonia or protonated amine in sludge can be easily converted to volatile ammonia, resulting in a significant

  14. Acoustic Sample Deposition MALDI-MS (ASD-MALDI-MS): A Novel Process Flow for Quality Control Screening of Compound Libraries.

    Science.gov (United States)

    Chin, Jefferson; Wood, Elizabeth; Peters, Grace S; Drexler, Dieter M

    2016-02-01

    In the early stages of drug discovery, high-throughput screening (HTS) of compound libraries against pharmaceutical targets is a common method to identify potential lead molecules. For these HTS campaigns to be efficient and successful, continuous quality control of the compound collection is necessary and crucial. However, the large number of compound samples and the limited sample amount pose unique challenges. Presented here is a proof-of-concept study for a novel process flow for the quality control screening of small-molecule compound libraries that consumes only minimal amounts of samples and affords compound-specific molecular data. This process employs an acoustic sample deposition (ASD) technique for the offline sample preparation by depositing nanoliter volumes in an array format onto microscope glass slides followed by matrix-assisted laser desorption/ionization mass spectrometric (MALDI-MS) analysis. An initial study of a 384-compound array employing the ASD-MALDI-MS workflow resulted in a 75% first-pass positive identification rate with an analysis time of <1 s per sample. © 2015 Society for Laboratory Automation and Screening.

  15. Longevity of granular iron in groundwater treatment processes: solution composition effects on reduction of organohalides and nitroaromatic compounds.

    Science.gov (United States)

    Klausen, Jörg; Vikesland, Peter J; Kohn, Tamar; Burris, David R; Ball, William P; Roberts, A Lynn

    2003-03-15

    Although granular iron permeable reactive barriers (PRBs) are increasingly employed to contain subsurface contaminants, information pertaining to system longevity is sparse. The present investigation redresses this situation by examining the long-term effects of carbonate, silica, chloride, and natural organic matter (NOM) on reactivity of Master Builders iron toward organohalides and nitroaromatic contaminants. Six columns were operated for 1100 days (approximately 4500 pore volumes) and five others for 407 days (approximately 1800 pore volumes). Nine were continuously exposed to mixtures of contaminant species, while the other two were only intermittently exposed in order to differentiate deactivation induced by water (and inorganic cosolutes) from that resulting from contaminant reduction. Contaminants investigated were trichloroethylene, 1,2,3-trichloropropane, 1,1-dichloroethane, 2-nitrotoluene, 4-nitroacetophenone, and 4-nitroanisole. Column reactivity declined substantially over the first 300 days and was dependent on the feed solution chemistry. High carbonate concentrations enhanced reactivity slightly within the first 90 days but produced poorer performance over the long term. Both silica and NOM adversely affected reactivity, while chloride evinced a somewhat mixed effect. Observed contrasts in relative reactivities suggest that trichloroethylene, 1,2,3-trichloropropane, and nitroaromatic compounds all react at different types of reactive sites. Our results indicate that differences in groundwater chemistry should be considered in the PRB design process.

  16. A process to preserve valuable compounds and acquire essential oils from pomelo flavedo using a microwave irradiation treatment.

    Science.gov (United States)

    Liu, Zaizhi; Zu, Yuangang; Yang, Lei

    2017-06-01

    A microwave pretreatment method was developed to preserve pectin, naringin, and limonin contents in pomelo flavedo to allow for longer storage times and subsequent extraction of pomelo essential oil. In terms of the essential oil, microwave pretreatment performed better than hydrodistillation with respect to extraction efficiency (1.88±0.06% in 24min versus 1.91±0.08% in 240min), oxygenation fraction (48.59±1.32% versus 29.63±1.02%), energy consumption (0.15kWh versus 1.54kWh), and environmental impact (123.20g CO 2 versus 1232g CO 2 ). Microwave-pretreated samples retained higher amounts of pectin, naringin, and limonin compared with non-pretreated samples. No obvious change in the degree of pectin esterification was observed. This study shows that the proposed process is a promising methodology for both preserving valuable compounds in pomelo flavedo during storage and acquiring essential oils. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Lattice Gas Model Based Optimization of Plasma-Surface Processes for GaN-Based Compound Growth

    Science.gov (United States)

    Nonokawa, Kiyohide; Suzuki, Takuma; Kitamori, Kazutaka; Sawada, Takayuki

    2001-10-01

    Progress of the epitaxial growth technique for GaN-based compounds makes these materials attractive for applications in high temperature/high-power electronic devices as well as in short-wavelength optoelectronic devices. For MBE growth of GaN epilayer, atomic nitrogen is usually supplied from ECR-plasma while atomic Ga is supplied from conventional K-cell. To grow high-quality epilayer, fundamental knowledge of the detailed atomic process, such as adsorption, surface migration, incorporation, desorption and so forth, is required. We have studied the influence of growth conditions on the flatness of the growth front surface and the growth rate using Monte Carlo simulation based on the lattice gas model. Under the fixed Ga flux condition, the lower the nitrogen flux and/or the higher the growth temperature, the better the flatness of the front surface at the sacrifice of the growth rate of the epilayer. When the nitrogen flux is increased, the growth rate reaches saturation value determined from the Ga flux. At a fixed growth temperature, increasing of nitrogen to Ga flux ratio results in rough surface owing to 3-dimensional island formation. Other characteristics of MBE-GaN growth using ECR-plasma can be well reproduced.

  18. Participation of oxidized sulfur center in intramolecular free radical processes in the model organic compounds of biological importance

    International Nuclear Information System (INIS)

    Pogocki, D.M.

    2004-01-01

    The pathogenesis of neurodegenerative diseases such as prion diseases (Creutzfeldt-Jacob disease) and Alzheimer's disease is strongly associated with the presence of β-amyloid peptide (βA) and prion protein (hPrP) in the brain tissue. Both macromolecules contain methionine (Met) residues. Their presence seems to be responsible for unique redox properties of βA and hPrP. These residues may undergo relatively easy autooxidation and/or metal-catalysed oxidation. The presented studies were focused on the potential function of Met residues as antioxidants or pro-oxidants and on their role in radical-mediated oxidation of peptides and proteins. The role of S-, O-, N- and C-centered radicals generated in various oligopeptides containing Met and relevant model compounds has been examined in detail with respect to formation of 2c-3e bonds, redox processes, fragmentation and their mutual interconversion. In order to achieve these goals several experimental radiation, photochemical, and molecular modelling methods were applied. The experimental and molecular modelling results show significant influence of functional neighbouring groups and conformational flexibility of a peptide backbone on the oxidative reduction pathway in oligopeptides containing single and multiple Met residues. The results presented here allow for better understanding of the known propensities of βA and hPrP to reduce transition metals and to form reactive oxygen species and free radicals. (author)

  19. Effect of Spanish style processing on the phenolic compounds and antioxidant activity of Algerian green table olives

    Directory of Open Access Journals (Sweden)

    Mettouchi, S.

    2016-03-01

    Full Text Available The study was carried out on seven Algerian olive cultivars to report the effect of Spanish style processing on individual and total phenolic compounds and the changes that occur in antioxidant capacity. The results indicate that the treatment leads to losses in phenolic contents which are cultivar dependent. Sigoise is the least affected variety (12.25% and Azzeradj from Seddouk the most affected one (94.80%. The phenolic profile shows drastic changes after processing. Hydroxytyrosol is dominant in processed olives (14.42–545.42 mg.100 g-1 while oleuropein is the major phenolic compound in fresh olives (994.27 mg.100 g-1. As a consequence to the loss in phenolic content, substantial reductions in the antioxidant activities of the extracts are noted. They are estimated to be 13.12–92.75% in scavenging activity against the DPPH radical, 37.78–93.98% in reducing capacity, 59.45–97.94% in the hydrogen peroxide radical and 7.26–51.66% in the inhibition bleaching of β-carotene. Among the processed varieties, only Sigoise presented a positive value of RACI (relative antioxidant capacity index.El estudio se llevó a cabo con siete variedades de aceitunas argelinas y se investigó el efecto de la elaboración al estilo español sobre los compuestos fenólicos individuales y totales; así como los cambios que se producen en la capacidad antioxidante. Los resultados obtenidos muestran que el procesamiento conduce a pérdidas en el contenido fenólico, lo cual es dependiente de la variedad. Sigoise es la variedad menos afectada (12.25% y Azzeradj de Seddouk la más (94.80%. El perfil fenólico muestra cambios drásticos después de su procesamiento. El hidroxitirosol es el polifenol predominante en aceitunas procesadas (14.42–545.42 mg·100 g−1, mientras que la oleuropeína es el compuesto fenólico mayoritario en las aceitunas frescas (994.27 mg·100 g−1. En consonancia con la pérdida en estos polifenoles, se detectaron reducciones

  20. Characterization of Key Aroma Compounds in Raw and Thermally Processed Prawns and Thermally Processed Lobsters by Application of Aroma Extract Dilution Analysis.

    Science.gov (United States)

    Mall, Veronika; Schieberle, Peter

    2016-08-24

    Application of aroma extract dilution analysis (AEDA) to an aroma distillate of blanched prawn meat (Litopenaeus vannamei) (BPM) revealed 40 odorants in the flavor dilution (FD) factor range from 4 to 1024. The highest FD factors were assigned to 2-acetyl-1-pyrroline, 3-(methylthio)propanal, (Z)-1,5-octadien-3-one, trans-4,5-epoxy-(E)-2-decenal, (E)-3-heptenoic acid, and 2-aminoacetophenone. To understand the influence of different processing conditions on odorant formation, fried prawn meat was investigated by means of AEDA in the same way, revealing 31 odorants with FD factors between 4 and 2048. Also, the highest FD factors were determined for 2-acetyl-1-pyrroline, 3-(methylthio)propanal, and (Z)-1,5-octadien-3-one, followed by 4-hydroxy-2,5-dimethyl-3(2H)-furanone, (E)-3-heptenoic acid, and 2-aminoacetophenone. As a source of the typical marine, sea breeze-like odor attribute of the seafood, 2,4,6-tribromoanisole was identified in raw prawn meat as one of the contributors. Additionally, the aroma of blanched prawn meat was compared to that of blanched Norway and American lobster meat, respectively (Nephrops norvegicus and Homarus americanus). Identification experiments revealed the same set of odorants, however, with differing FD factors. In particular, 3-hydroxy-4,5-dimethyl-2(5H)-furanone was found as the key aroma compound in blanched Norway lobster, whereas American lobster contained 3-methylindole with a high FD factor.

  1. Retardation effect of nitrogen compounds and condensed aromatics on shale oil catalytic cracking processing and their characterization.

    Science.gov (United States)

    Li, Nan; Chen, Chen; Wang, Bin; Li, Shaojie; Yang, Chaohe; Chen, Xiaobo

    Untreated shale oil, shale oil treated with HCl aqueous solution and shale oil treated with HCl and furfural were used to do comparative experiments in fixed bed reactors. Nitrogen compounds and condensed aromatics extracted by HCl and furfural were characterized by electrospray ionization Fourier transform cyclotron resonance mass spectrometry and gas chromatography and mass spectrometry, respectively. Compared with untreated shale oil, the conversion and yield of liquid products increased considerably after removing basic nitrogen compounds by HCl extraction. Furthermore, after removing nitrogen compounds and condensed aromatics by both HCl and furfural, the conversion and yield of liquid products further increased. In addition, N 1 class species are predominant in both basic and non-basic nitrogen compounds, and they are probably indole, carbazole, cycloalkyl-carbazole, pyridine and cycloalkyl-pyridine. As for the condensed aromatics, most of them possess aromatic rings with two to three rings and zero to four carbon atom.

  2. Isotherm and kinetic studies on adsorption of oil sands process-affected water organic compounds using granular activated carbon.

    Science.gov (United States)

    Islam, Md Shahinoor; McPhedran, Kerry N; Messele, Selamawit A; Liu, Yang; Gamal El-Din, Mohamed

    2018-07-01

    The production of oil from oil sands in northern Alberta has led to the generation of large volumes of oil sands process-affected water (OSPW) that was reported to be toxic to aquatic and other living organisms. The toxicity of OSPW has been attributed to the complex nature of OSPW matrix including the inorganic and organic compounds primarily naphthenic acids (NAs: C n H 2n+Z O x ). In the present study, granular activated carbon (GAC) adsorption was investigated for its potential use to treat raw and ozonated OSPW. The results indicated that NA species removal increased with carbon number (n) for a fixed Z number; however, the NA species removal decreased with Z number for a fixed carbon number. The maximum adsorption capacities obtained from Langmuir adsorption isotherm based on acid-extractable fraction (AEF) and NAs were 98.5 mg and 60.9 mg AEF/g GAC and 60 mg and 37 mg NA/g GAC for raw and ozonated OSPW, respectively. It was found that the Freundlich isotherm model best fits the AEF and NA equilibrium data (r 2  ≥ 0.88). The adsorption kinetics showed that the pseudo-second order and intraparticle diffusion models were both appropriate in modeling the adsorption kinetics of AEF and NAs to GAC (r 2  ≥ 0.97). Although pore diffusion was the rate limiting step, film diffusion was still significant for assessing the rate of diffusion of NAs. This study could be helpful to model, design and optimize the adsorption treatment technologies of OSPW and to assess the performance of other adsorbents. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Modification of the processes of resorption of alpha-emitting nuclides from gastrointestinal tract depending of the properties of the compounds administered and the physiological status of rats

    International Nuclear Information System (INIS)

    Zalikin, G.A.; Moskalev, Yu.I.; Nisimov, P.G.; Romanova, I.B.

    1986-01-01

    In experiments on rats a study was made of resorption from the gastrointestinal tract of simple salts, complex compounds and ''biologically incorporated'' forms of transuranium nuclides, the influence of age, pregnancy and chemically active substances (for instance, trivalent iron and ethyl alcohol) on this process

  4. Extraction and purification of high added value compounds from by-products of the winemaking chain using alternative/nonconventional processes/technologies.

    Science.gov (United States)

    Yammine, Sami; Brianceau, Sylène; Manteau, Sébastien; Turk, Mohammad; Ghidossi, Rémy; Vorobiev, Eugène; Mietton-Peuchot, Martine

    2018-05-24

    Grape byproducts are today considered as a cheap source of valuable compounds since existent technologies allow the recovery of target compounds and their recycling. The goal of the current article is to explore the different recovery stages used by both conventional and alternative techniques and processes. Alternative pre-treatments techniques reviewed are: ultrasounds, pulsed electric fields and high voltage discharges. In addition, nonconventional solvent extraction under high pressure, specifically, supercritical fluid extraction and subcritical water extraction are discussed. Finally alternative purification technologies, for example membrane processing were also examined. The intent is to describe the mechanisms involved by these alternative technologies and to summarize the work done on the improvement of the extraction process of phenolic compounds from winery by-products. With a focus on the developmental stage of each technology, highlighting the research need and challenges to be overcome for an industrial implementation of these unitary operations in the overall extraction process. A critical comparison of conventional and alternative techniques will be reviewed for ethe pre-treatment of raw material, the diffusion of polyphenols and the purification of these high added value compounds. This review intends to give the reader some key answers (costs, advantages, drawbacks) to help in the choice of alternative technologies for extraction purposes.

  5. Literature review on production process to obtain extra virgin olive oil enriched in bioactive compounds. Potential use of byproducts as alternative sources of polyphenols.

    Science.gov (United States)

    Frankel, Edwin; Bakhouche, Abdelhakim; Lozano-Sánchez, Jesús; Segura-Carretero, Antonio; Fernández-Gutiérrez, Alberto

    2013-06-05

    This review describes the olive oil production process to obtain extra virgin olive oil (EVOO) enriched in polyphenol and byproducts generated as sources of antioxidants. EVOO is obtained exclusively by mechanical and physical processes including collecting, washing, and crushing of olives, malaxation of olive paste, centrifugation, storage, and filtration. The effect of each step is discussed to minimize losses of polyphenols from large quantities of wastes. Phenolic compounds including phenolic acids, alcohols, secoiridoids, lignans, and flavonoids are characterized in olive oil mill wastewater, olive pomace, storage byproducts, and filter cake. Different industrial pilot plant processes are developed to recover phenolic compounds from olive oil byproducts with antioxidant and bioactive properties. The technological information compiled in this review will help olive oil producers to improve EVOO quality and establish new processes to obtain valuable extracts enriched in polyphenols from byproducts with food ingredient applications.

  6. Compounds from Cynomorium songaricum with Estrogenic and Androgenic Activities Suppress the Oestrogen/Androgen-Induced BPH Process.

    Science.gov (United States)

    Wang, Xueni; Tao, Rui; Yang, Jing; Miao, Lin; Wang, Yu; Munyangaju, Jose Edouard; Wichai, Nuttapong; Wang, Hong; Zhu, Yan; Liu, Erwei; Chang, Yanxu; Gao, Xiumei

    2017-01-01

    To investigate the phytoestrogenic and phytoandrogenic activities of compounds isolated from CS and uncover the role of CS in prevention of oestrogen/androgen-induced BPH. Cells were treated with CS compounds, and immunofluorescence assay was performed to detect the nuclear translocation of ER α or AR in MCF-7 or LNCaP cells; luciferase reporter assay was performed to detect ERs or AR transcriptional activity in HeLa or AD293 cells; MTT assay was performed to detect the cell proliferation of MCF-7 or LNCaP cells. Oestrogen/androgen-induced BPH model was established in rat and the anti-BPH, anti-estrogenic, and anti-androgenic activities of CS in vivo were further investigated. The nuclear translocation of ER α was stimulated by nine CS compounds, three of which also stimulated AR translocation. The transcriptional activities of ER α and ER β were induced by five compounds, within which only ECG induced AR transcriptional activity as well. Besides, ECG stimulated the proliferation of both MCF-7 cells and LNCaP cells. CS extract suppressed oestrogen/androgen-induced BPH progress in vivo by downregulation of E2 and T level in serum and alteration of the expressions of ER α , ER β , and AR in the prostate. Our data demonstrates that compounds from CS exhibit phytoestrogenic and phytoandrogenic activities, which may contribute to inhibiting the oestrogen/androgen-induced BPH development.

  7. Removal of organic carbon and sulphur compounds from process and fugitive emissions. Phase 1: Results from laboratory studies

    International Nuclear Information System (INIS)

    Coleman, R.N.

    1994-01-01

    Lab-scale biofilters were constructed from black polypropylene plastic tubing with internal dimensions of 5 by 100 cm. A biofilter matrix was provided using coarse sphagnum peat which was washed with water and inoculated with enriched cultures of appropriate microorganisms. Compressed air was applied to the biofilters and various compounds were added to the air stream at appropriate concentrations. These compounds included hydrogen sulfide, n-hexane, cyclohexane, propionic acid, and butyric acid. Removal efficiency was evaluated for each compound. Over 99% of the hydrogen sulfide was removed, at concentrations of up to 125 ppM by volume. Removal levels of n-hexane, cyclohexane, and the organic acids were lower. Thiophene was not demonstrated as being removed. Numbers of microorganisms were assessed and their identity determined throughout the biofilter matrix. A mass balance for sulfur was determined throughout the biofilter system and showed 3.5% of sulfur unaccounted for. 9 refs., 9 figs., 7 tabs

  8. Patterns and Meanings of English Words through Word Formation Processes of Acronyms, Clipping, Compound and Blending Found in Internet-Based Media

    Directory of Open Access Journals (Sweden)

    Rio Rini Diah Moehkardi

    2017-02-01

    Full Text Available This research aims to explore the word-formation process in English new words found in the internet-based media through acronym, compound,  clipping and blending and their meanings. This study applies Plag’s (2002 framework of acronym and compound; Jamet’s (2009 framework of clipping, and Algeo’s framework (1977 in Hosseinzadeh  (2014 for blending. Despite the  formula established in each respective framework,  there could be occurrences  of novelty and modification on how words are formed and  how meaning developed in  the newly formed words. The research shows that well accepted acronyms can become real words by taking lower case and affixation. Some acronyms initialized non-lexical words, used non initial letters, and used letters and numbers that pronounced the same with the words they represent. Compounding also includes numbers as the element member of the compound. The nominal nouns are likely to have metaphorical and idiomatic meanings. Some compounds evolve to new and more specific meaning. The study also finds that back-clipping is the most dominant clipping. In blending, the sub-category clipping of blending, the study finds out that when clipping takes place, the non-head element is back-clipped and the head is fore-clipped.

  9. Trace detection of organic compounds in complex sample matrixes by single photon ionization ion trap mass spectrometry: real-time detection of security-relevant compounds and online analysis of the coffee-roasting process.

    Science.gov (United States)

    Schramm, Elisabeth; Kürten, Andreas; Hölzer, Jasper; Mitschke, Stefan; Mühlberger, Fabian; Sklorz, Martin; Wieser, Jochen; Ulrich, Andreas; Pütz, Michael; Schulte-Ladbeck, Rasmus; Schultze, Rainer; Curtius, Joachim; Borrmann, Stephan; Zimmermann, Ralf

    2009-06-01

    An in-house-built ion trap mass spectrometer combined with a soft ionization source has been set up and tested. As ionization source, an electron beam pumped vacuum UV (VUV) excimer lamp (EBEL) was used for single-photon ionization. It was shown that soft ionization allows the reduction of fragmentation of the target analytes and the suppression of most matrix components. Therefore, the combination of photon ionization with the tandem mass spectrometry (MS/MS) capability of an ion trap yields a powerful tool for molecular ion peak detection and identification of organic trace compounds in complex matrixes. This setup was successfully tested for two different applications. The first one is the detection of security-relevant substances like explosives, narcotics, and chemical warfare agents. One test substance from each of these groups was chosen and detected successfully with single photon ionization ion trap mass spectrometry (SPI-ITMS) MS/MS measurements. Additionally, first tests were performed, demonstrating that this method is not influenced by matrix compounds. The second field of application is the detection of process gases. Here, exhaust gas from coffee roasting was analyzed in real time, and some of its compounds were identified using MS/MS studies.

  10. Analysis of “Favorable Growth Element” Based on Rare Earth-aluminum Composite Mechanism of Compound Process

    Science.gov (United States)

    Hao, Baohong; Zeng, Qihui; Zhao, Jin

    2018-01-01

    Under the background that failure resulted in by high temperature once only aluminum oxide is used as the gasoline additive. This paper, with the purpose to solve this problem, is to synthesize AcAl oxide for gasoline additive. In order to get the rare-earth-aluminum oxide, first, a complex model of rare earth oxide based on theories about ion coordination is established. Then, by the complex model, the type of “compound growth unit” when rare earth elements join the hydrothermal conditions and the inclination that “diversification” might probably happen are deduced. Depending on the results got by complex model, this paper introduces the type of compound and its existence conditions of “Compound growth unit” owned by stable rare-earth-aluminum oxide. By adjusting the compositions of modifier, compound materials of rare earth-aluminum oxide used for gasoline additive is made. By XRD test, aperture test, adsorption test and desorption test, the theoretical deduction is proved to be right. From the experiment, it is concluded that: a dense environment is the pre-condition to form rare-earth-aluminum polymer, which is also an essential condition for the polymer to update to a favorable growth unit and produce mesoporous rare-earth-aluminum oxide with high activity.

  11. Segmentation algorithm for non-stationary compound Poisson processes. With an application to inventory time series of market members in a financial market

    Science.gov (United States)

    Tóth, B.; Lillo, F.; Farmer, J. D.

    2010-11-01

    We introduce an algorithm for the segmentation of a class of regime switching processes. The segmentation algorithm is a non parametric statistical method able to identify the regimes (patches) of a time series. The process is composed of consecutive patches of variable length. In each patch the process is described by a stationary compound Poisson process, i.e. a Poisson process where each count is associated with a fluctuating signal. The parameters of the process are different in each patch and therefore the time series is non-stationary. Our method is a generalization of the algorithm introduced by Bernaola-Galván, et al. [Phys. Rev. Lett. 87, 168105 (2001)]. We show that the new algorithm outperforms the original one for regime switching models of compound Poisson processes. As an application we use the algorithm to segment the time series of the inventory of market members of the London Stock Exchange and we observe that our method finds almost three times more patches than the original one.

  12. Ozonation of hospital raw wastewaters for cytostatic compounds removal. Kinetic modelling and economic assessment of the process

    Energy Technology Data Exchange (ETDEWEB)

    Ferre-Aracil, J. [Universitat Politècnica de València – EPSA, Department of Chemical and Nuclear Engineering. Institute for Industrial, Radiophysical and Environmental Safety (ISIRYM), Pl. Ferrandiz i Carbonell, 03801 Alcoi, Alicante (Spain); Valcárcel, Y. [Environmental Health and Ecotoxicology Research Group, Universidad Rey Juan Carlos, Avd. Atenas s/n, Móstoles, 28922 Alcorcón (Spain); Negreira, N.; López de Alda, M. [Water and Soil Quality Research Group, Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA-CSIC), C/ Jordi Girona 18-26, 08034 Barcelona (Spain); Barceló, D. [Water and Soil Quality Research Group, Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA-CSIC), C/ Jordi Girona 18-26, 08034 Barcelona (Spain); Catalan Institute for Water Research (ICRA), H2O Building, Scientific and Technological Park of the University of Girona, Emili Grahit 101, 17003 Girona (Spain); Cardona, S.C. [Universitat Politècnica de València – EPSA, Department of Chemical and Nuclear Engineering. Institute for Industrial, Radiophysical and Environmental Safety (ISIRYM), Pl. Ferrandiz i Carbonell, 03801 Alcoi, Alicante (Spain); Navarro-Laboulais, J., E-mail: jnavarla@iqn.upv.es [Universitat Politècnica de València – EPSA, Department of Chemical and Nuclear Engineering. Institute for Industrial, Radiophysical and Environmental Safety (ISIRYM), Pl. Ferrandiz i Carbonell, 03801 Alcoi, Alicante (Spain)

    2016-06-15

    The kinetics of the ozone consumption for the pretreatment of hospital wastewater has been analysed in order to determine the reaction rate coefficients between the ozone and the readily oxidisabled organic matter and cytostatic compounds. The wastewater from a medium size hospital was treated with ozone and peroxone methodologies, varying the ozone concentration, the reaction time and the hydrogen peroxide doses. The analysis shows that there are four cytostatic compounds, i.e. irinotecan, ifosfamide, cyclophosphamide and capecitabine, detected in the wastewaters and they are completely removed with reasonably short times after the ozone treatment. Considering the reactor geometry, the gas hydrodynamics, the mass transfer of ozone from gas to liquid and the reaction of all oxidisable compounds of the wastewater it is possible to determine the chemical ozone demand, COzD, of the sample as 256 mg O{sub 3} L{sup −1} and the kinetic rate coefficient with the dissolved organic matter as 8.4 M{sup −1} s{sup −1}. The kinetic rate coefficient between the ozone and the cyclophosphamide is in the order of 34.7 M{sup −1} s{sup −1} and higher for the other cytostatics. The direct economic cost of the treatment was evaluated considering this reaction kinetics and it is below 0.3 €/m{sup 3} under given circumstances. - Highlights: • 17 cytostatic compounds were analysed and 4 detected by SPE-LC/MS-MS. • The ozonation is 100% effective on the removal of the detected cytostatics. • The kinetics of cytostatic ozonation reaction is modeled by competitive kinetics. • The economic cost of the treatment of hospital wastewater was assessed.

  13. Ozonation of hospital raw wastewaters for cytostatic compounds removal. Kinetic modelling and economic assessment of the process

    International Nuclear Information System (INIS)

    Ferre-Aracil, J.; Valcárcel, Y.; Negreira, N.; López de Alda, M.; Barceló, D.; Cardona, S.C.; Navarro-Laboulais, J.

    2016-01-01

    The kinetics of the ozone consumption for the pretreatment of hospital wastewater has been analysed in order to determine the reaction rate coefficients between the ozone and the readily oxidisabled organic matter and cytostatic compounds. The wastewater from a medium size hospital was treated with ozone and peroxone methodologies, varying the ozone concentration, the reaction time and the hydrogen peroxide doses. The analysis shows that there are four cytostatic compounds, i.e. irinotecan, ifosfamide, cyclophosphamide and capecitabine, detected in the wastewaters and they are completely removed with reasonably short times after the ozone treatment. Considering the reactor geometry, the gas hydrodynamics, the mass transfer of ozone from gas to liquid and the reaction of all oxidisable compounds of the wastewater it is possible to determine the chemical ozone demand, COzD, of the sample as 256 mg O 3 L −1 and the kinetic rate coefficient with the dissolved organic matter as 8.4 M −1 s −1 . The kinetic rate coefficient between the ozone and the cyclophosphamide is in the order of 34.7 M −1 s −1 and higher for the other cytostatics. The direct economic cost of the treatment was evaluated considering this reaction kinetics and it is below 0.3 €/m 3 under given circumstances. - Highlights: • 17 cytostatic compounds were analysed and 4 detected by SPE-LC/MS-MS. • The ozonation is 100% effective on the removal of the detected cytostatics. • The kinetics of cytostatic ozonation reaction is modeled by competitive kinetics. • The economic cost of the treatment of hospital wastewater was assessed.

  14. Influence of pulsed electric field treatments on the volatile compounds of milk in comparison with pasteurized processing.

    Science.gov (United States)

    Zhang, Sha; Yang, Ruijin; Zhao, Wei; Hua, Xiao; Zhang, Wenbin; Zhang, Zhong

    2011-01-01

    Effects of pulsed electric field (PEF) treatments on the volatile profiles of milk were studied and compared with pasteurized treatment of high temperature short time (HTST) (75 °C, 15 s). Volatile compounds were extracted by solid-phase micro-extraction (SPME) and identified by gas chromatography/mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O). A total of 37 volatile compounds were determined by GC-MS, and 19 volatile compounds were considered to be major contributors to the characteristic flavor of milk samples. PEF treatment resulted in an increase in aldehydes. Milk treated with PEF at 30 kV/cm showed the highest content of pentanal, hexanal, and nonanal, while heptanal and decanal contents were lower than in pasteurized milk, but higher than in raw milk. All the methyl ketones detected in PEF milk were lower than in pasteurized milk. No significant differences in acids (acetic acid, butanoic acid, hexanoic acid, octanoic acid, and decanoic acid), lactones, and alcohols were observed between pasteurized and PEF-treated samples; however, 2(5H)-furanone was only detected in PEF-treated milk. Although GC-MS results showed that there were some volatile differences between pasteurized and PEF-treated milk, GC-O data showed no significant difference between the 2 samples.

  15. Modeling of volatile and phenolic compounds and optimization of the process conditions for obtaining balanced extra virgin olive oils

    Directory of Open Access Journals (Sweden)

    A. M. Vidal

    2018-06-01

    Full Text Available The main objective of this paper is to obtain extra virgin olive oils (EVOOs which are balanced in volatile and phenolic compounds. An experimental design was performed and response surface methodology was applied. The factors for malaxation were: temperature 20-40 °C, time 30-90 min, and hole diameter of hammer-crusher 4.5-6.5 mm. The results show that high temperatures and small hole diameter must be used in order to obtain a higher content in phenolic compounds, while for volatile compounds a low temperature and large hole diameter must be used. The models predict that the best and more balanced EVOO are obtained with the hole diameter of greater size and a medium-low temperature. Thus, for a hammer-crusher hole diameter of 6.5 mm 337 and 356 mg/kg total HPLC phenols were obtained for malaxation temperature of 20 and 25 °C, respectively and, likewise, 12.7 and 11.5 mg/kg total LOX volatiles.

  16. Effect of kind of solid fuel onto noxious compound emissions in the firing up process of a low output water boiler

    International Nuclear Information System (INIS)

    Wilk, R.; Szymczyk, J.; Zielinski, Z.; Wystemp, E.

    1992-01-01

    NO x , SO 2 , CO and polynuclear aromatic hydrocarbon emission tests were carried out during the firing up process of a low output boiler for three kinds of smokeless solid fuels and boiler coal. It has been stated that the use of low emissive fuels in low output boilers did not protect against noxious compound emissions during firing up the boiler. (author). 13 refs, 8 figs, 4 tabs

  17. Synthesis and application of bismuth ferrite nanosheets supported functionalized carbon nanofiber for enhanced electrochemical detection of toxic organic compound in water samples.

    Science.gov (United States)

    Ramaraj, Sukanya; Mani, Sakthivel; Chen, Shen-Ming; Kokulnathan, Thangavelu; Lou, Bih-Show; Ali, M Ajmal; Hatamleh, A A; Al-Hemaid, Fahad M A

    2018-03-15

    Recently, the multiferroic material has fabulous attention in numerous applications owing to its excellent electronic conductivity, unique mechanical property, and higher electrocatalytic activity, etc. In this paper, we reported that the synthesis of bismuth ferrite (BiFeO 3 ) nanosheets integrated functionalized carbon nanofiber (BiFeO 3 NS/F-CNF) nanocomposite using a simple hydrothermal technique. Herein, the structural changes and crystalline property of prepared BiFeO 3 NS/F-CNF nanocomposite were characterized using Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). From this detailed structural evolution, the formation of nanosheets like BiFeO 3 and its nanocomposite with F-CNF were scrutinized and reported. Furthermore, the as-prepared BiFeO 3 NS/F-CNF nanocomposite modified glassy carbon electrode (GCE) was applied for electrochemical detection of catechol (CC). As expected, BiFeO 3 NS/F-CNF/GCE shows excellent electrocatalytic activity as well as 3.44 (F-CNF/GCE) and 7.92 (BiFeO 3 NS/GCE) fold higher electrochemical redox response for CC sensing. Moreover, the proposed sensor displays a wide linear range from 0.003 to 78.02 µM with a very low detection limit of 0.0015 µM. In addition, we have validated the real-time application of our developed CC sensor in different water samples. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Characterization of chemical compounds for dosimetry of the radiation in industrial processes; Caracterizacao de compostos quimicos para dosimetria das radiacaoes em processos industriais

    Energy Technology Data Exchange (ETDEWEB)

    Galante, Ana Maria Sisti

    1999-07-01

    Different chemical compounds have been studied to optimize dosimetric systems in irradiation processes. In this study 2,3,5 Triphenyl -2H- Tetrazolium Chloride, Brilliant Cresyl Blue, Bromocresol Green and Potassium Nitrate were investigated for their merits or faults, for {sup 60} Co gamma field, in order to verify if can be considered as dosimeters. Fricke solution was used as reference dosimeter to determine absorption dose rates at the gamma facilities.Only Bromocresol Green and Potassium Nitrate are recommended for dosimetry purposes since the main characteristics were achieved. The other two compounds could be used in dosimetry with changes in their formulation. Bromocresol Green and potassium Nitrate are reproducible and radiation sensitive for absorbed doses from 300 Gy to 150 kGy Bromocresol Green was used in liquid form and Potassium Nitrate was prepared in solid pellets form. Spectrophotometry in the visible region was used as the main detection technique, which allows relating optical absorption, before and after irradiation, with the absorbed dose. The maximum absorption wavelength for each compound was observed at 450-460nm for bromocresol Green and 546nm for Potassium Nitrate. Dose calibration curves are linear for both compounds in all dose intervals. When irradiated with accelerated electrons, with energies between o,9 MeV and 1,5MeV, optical absorption intensification, of about 2,6 times, was observed when comparing results for Potassium Nitrate, with those for gamma rays. All the evaluations are presented in this work. (author)

  19. Volatile molecular markers of VOO Thermo-oxidation: Effect of heating processes, macronutrients composition, and olive ripeness on the new emitted aldehydic compounds.

    Science.gov (United States)

    Oueslati, Imen; Manaï, Hédia; Madrigal-Martínez, Mónica; Martínez-Cañas, Manuel A; Sánchez-Casas, Jacinto; Zarrouk, Mokhtar; Flamini, Guido

    2018-04-01

    Heating operation has been applied to Chétoui extra-virgin olive oils (EVOOs) extracted from fruits with several ripening stages (RS). The studied samples, were subjected to microwave and conventional heating. Results showed that heated VOOs after 2.5 h and 7 min of conventional and microwave heating, respectively, gave rise to a drastically decrease of LOX products and allowed the detection of toxic new formed aldehydic volatiles (alkanal: nonanal, alkenals: (Z)-2-heptenal and (E)-2-decenal, and alkadienals: (E.E)-2.4-decadienal), which can be used as markers of VOO degradation. Their abundance in the VOO headspaces depends on their boiling points, the rate of their possible degradation to yield other compounds, on the heating processes and on the rate of macronutrients. The emission rate of the new synthesized volatiles during heating processes was mainly attributed to enzymatic oxidation of some fatty acids. Hexanal, (Z)-2-heptenal, (E)-2-octenal, (E)-2-nonenal, (E,E) and (E,Z)-2,4-decadienal, and (E,E)-2,4-nonadienal, derived from linoleic acid, and heptanol, octanal, nonanal, decanal, (E) and (Z)-2-decenal, (E)-2-undecenal, and (E,E)-2,4-nonadienal, are emitted after degradation of oleic acid. During thermo-oxidation, the ECN 44 (LLO, and OLnO), and the ECN 46 (OLO, and PLO + SLL) compounds decreased, whereas, the ECN 48 (OOO, and PPO), and the ECN 50 (SOO) compounds increased when temperature and heating time increased. The several variations of the studied biochemical compounds depend to the heating processes. Ripening stage of olive fruits can be used as a tool to monitor the emission rate of the aldehydic volatiles, but cannot be used for a chemometric discrimination. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. Evaluation Of In Situ Steam-Injection Processes For Reduction Of Petroleum Compounds Within An Abandoned Canal

    Science.gov (United States)

    A conceptual approach of a novel application of in-situ thermal processes that would either use a steam injection process or a steam/surfactant injection process was considered to remediate petroleum contaminated sediment residing in an abandoned canal. Laboratory tests were c...

  1. Extraction of Citrus Hystrix D.C. (Kaffir Lime) Essential Oil Using Automated Steam Distillation Process: Analysis of Volatile Compounds

    International Nuclear Information System (INIS)

    Nurhani Kasuan; Zuraida Muhammad; Zakiah Yusoff; Mohd Hezri Fazalul Rahiman; Mohd Nasir Taib; Zaibunnisa Abdul Haiyee

    2013-01-01

    An automated steam distillation was successfully used to extract volatiles from Citrus hystrix D.C (Kaffir lime) peels. The automated steam distillation integrated with robust temperature control can commercially produce large amount of essential oil with efficient heating system. Objective of this study is to quantify the oil production rate using automated steam distillation and analyze the composition of volatiles in Kaffir lime peels oil at different controlled and uncontrolled temperature conditions. From the experimentation, oil extraction from Kaffir lime peels only took approximately less than 3 hours with amount of oil yield was 13.4 % more than uncontrolled temperature. The identified major compounds from Kaffir lime peels oil were sabinene, β-pinene, limonene, α-pinene, camphene, myrcene, terpinen-4-ol, α-terpineol, linalool, terpinolene and citronellal which are considered to have good organoleptic quality. In contrast with uncontrolled temperature, oil analysis revealed that some important volatile compounds were absent such as terpinolene, linalool, terpinen-4-ol due to thermal degradation effect from fast heating of extracted material. (author)

  2. Unusual effects of manual grinding and subsequent annealing process observed in Gd5.09Ge2.03Si1.88 compound

    Science.gov (United States)

    Carvalho, A. M. G.; Alves, C. S.; Trevizoli, P. V.; dos Santos, A. O.; Gama, S.; Coelho, A. A.

    2018-03-01

    The Gd5.09Ge2.03Si1.88 compound, as well as other magnetocaloric materials, certainly will not be used in their un-manufactured as-cast condition in future magnetic refrigeration applications or other devices. In this work, we have studied the Gd5.09Ge2.03Si1.88 compound processed in different ways, mainly, the as-cast powder, the annealed powder, and the pressed and sintered powder. The annealed powder (1370 K/20 h) does not present the monoclinic phase and the first-order magneto-structural transition observed in the as-cast powder. The pressed and sintered powder also do not present the first-order transition. Furthermore, the compacting pressure shifts the second-order magnetic transition to lower temperatures. The behavior of cell parameters as a function of the compacting pressure indicates that T C is directly affected by parameter c change.

  3. Hydrogen production with short contact time. Catalytic partial oxidation of hydrocarbons and oxygenated compounds: Recent advances in pilot- and bench-scale testing and process design

    Energy Technology Data Exchange (ETDEWEB)

    Guarinoni, A.; Ponzo, R.; Basini, L. [ENI Refining and Marketing Div., San Donato Milanese (Italy)

    2010-12-30

    ENI R and D has been active for fifteen years in the development of Short Contact Time - Catalytic Partial Oxidation (SCT-CPO) technologies for producing Hydrogen/Synthesis Gas. From the beginning the experimental work addressed either at defining the fundamental principles or the technical and economical potential of the technology. Good experimental responses, technical solutions' simplicity and flexibility, favourable techno-economical evaluations promoted the progressive widening of the field of the investigations. From Natural Gas (NG) the range of ''processable'' Hydrocarbons extended to Liquefied Petroleum Gas (LPG) and Gasoils, including those characterised by high levels of unsaturated and sulphurated molecules and, lately, to other compounds with biological origin. The extensive work led to the definition of different technological solutions, grouped as follows: Technology 1: Air Blown SCT-CPO of Gaseous Hydrocarbons and/or Light Compounds with biological origin Technology 2: Enriched Air/Oxygen Blown SCT-CPO of Gaseous Hydrocarbons and/or Light Compounds with biological origin Technology 3: Enriched Air/Oxygen Blown SCT-CPO of Liquid Hydrocarbons and/or Compounds with biological origin Recently, the licence rights on a non-exclusive basis for the commercialisation of SCT-CPO based processes for H{sub 2}/Synthesis gas production from light hydrocarbons with production capacity lower than 5,000 Nm{sup 3}/h of H{sub 2} or 7,500 Nm3/h of syngas have been assigned to two external companies. In parallel, development of medium- and large-scale plant solutions is progressing within the ENI group framework. These last activities are addressed to the utilisation of SCT-CPO for matching the variable Hydrogen demand in several contexts of oil refining operation. This paper will report on the current status of SCT-CPO with a focus on experimental results obtained, either at pilot- and bench- scale level. (orig.)

  4. Volatile compounds and changes in flavour-related enzymes during cold storage of high-intensity pulsed electric field- and heat-processed tomato juices.

    Science.gov (United States)

    Aguiló-Aguayo, Ingrid; Soliva-Fortuny, Robert; Martín-Belloso, Olga

    2010-08-15

    The effects of high-intensity pulsed electric field (HIPEF) processing (35 kV cm(-1) for 1500 micros, using 4 micros bipolar pulses at 100 Hz) on the production of volatile compounds and flavour-related enzymes in tomato juice were investigated and compared with those of thermal processing (90 degrees C for 30 or 60 s). Tomato juice treated by HIPEF showed lower residual lipoxygenase (LOX) activity (70.2%) than juice heated at 90 degrees C for 60 s (80.1%) or 30 s (93.2%). In contrast, hydroperoxide lyase (HPL) was almost completely inactivated when the juice was subjected to 90 degrees C for 60 s, whereas roughly 50% of the control tomato juice was depleted after HIPEF treatment or thermal processing at 90 degrees C for 30 s. A slight decrease was observed in the initial LOX activity of treated and untreated samples during storage, whereas initial HPL activity was strongly affected over time. HIPEF-treated juice exhibited higher levels of compounds contributing to tomato aroma than untreated and heat-treated juices throughout storage. Thus HIPEF processing can preserve flavour quality and stability of tomato juice compared with conventional thermal treatments. Copyright (c) 2010 Society of Chemical Industry.

  5. Studies in coal liquefaction with application to the SRC and related processes. Quarterly report, August 1981-October 1981. [Using model compounds

    Energy Technology Data Exchange (ETDEWEB)

    Tarrer, A. R.; Guin, J. A.; Curtis, C. W.

    1981-01-01

    Model compound reactions were studied to evaluate the effects of mass transfer, solvent type, solvent blending, hydrogen partial pressure, temperature, reactant concentration, additive loading and its preparation, etc. Naphthalene hydrogenation and benzothiophene hydrodesulfurization were investigated under the conditions comparable to commercial coal liquefaction and related processes. Both of these reaction systems were observed to be surface reaction controlled under the reaction conditions used in this work. Certain aromatic compounds were observed to cause a reduction in the reaction rates of naphthalene and benzothiophene. Single stage coal dissolution was investigated using tetralin as a hydrogen donor solvent and a commercial cobalt-molybdate catalyst. A spinning basket system was developed to allow injection of the catalyst at a desired time in the reaction cycle. This catalyst injection technique proved to be reliable for the exploratory work done here. The degree of catalyst deactivation was rated by comparing the activities of the spent catalyst for model compound (naphthalene and cumene) reactivities relative to those of the fresh catalyst. No substantial reduction in deactivation was observed to result with delayed contacting of the catalyst with the coal-tetralin reaction mixture. The effect of reaction temperature on the initial rate of catalyst deactivation was also studied.

  6. Phenolic compounds, antioxidant potential and antiproliferative potential of 10 common edible flowers from China assessed using a simulated in vitro digestion-dialysis process combined with cellular assays.

    Science.gov (United States)

    Huang, Weisu; Mao, Shuqin; Zhang, Liuquan; Lu, Baiyi; Zheng, Lufei; Zhou, Fei; Zhao, Yajing; Li, Maiquan

    2017-11-01

    Phenolic compounds could be sensitive to digestive conditions, thus a simulated in vitro digestion-dialysis process and cellular assays was used to determine phenolic compounds and antioxidant and antiproliferative potentials of 10 common edible flowers from China and their functional components. Gallic acid, ferulic acid, and rutin were widely present in these flowers, which demonstrated various antioxidant capacities (DPPH, ABTS, FRAP and CAA values) and antiproliferative potentials measured by the MTT method. Rosa rugosa, Paeonia suffruticosa and Osmanthus fragrans exhibited the best antioxidant and antiproliferative potentials against HepG2, A549 and SGC-7901 cell lines, except that Osmanthus fragrans was not the best against SGC-7901 cells. The in vitro digestion-dialysis process decreased the antioxidant potential by 33.95-90.72% and the antiproliferative potential by 13.22-87.15%. Following the in vitro digestion-dialysis process, phenolics were probably responsible for antioxidant (R 2 = 0.794-0.924, P digestion and dialysis along with the reduction of phenolics. Nevertheless, they still had considerable antioxidant and antiproliferative potential, which merited further investigation in in vivo studies. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  7. Influence of partial replacement of NaCl with KCl on profiles of volatile compounds in dry-cured bacon during processing.

    Science.gov (United States)

    Wu, Haizhou; Zhuang, Hong; Zhang, Yingyang; Tang, Jing; Yu, Xiang; Long, Men; Wang, Jiamei; Zhang, Jianhao

    2015-04-01

    This study investigated the influence of partial substitution of NaCl with KCl on the formation of volatile compounds in bacons during processing using a purge and trap dynamic headspace GC/MS system. Three substitutions were 0% KCl (I), 40% KCl (II), and 70% KCl (III). The profiles of the volatile compounds significantly changed during processing, particularly during the drying/ripening. At the end of process, the bacons from substitution III formed significantly higher levels of lipid-derived volatiles, such as straight chain aldehydes, hydrocarbons than bacons from substitution I and II, whereas the latter formed higher levels of volatiles from amino acid degradation such as 3-methylbutanal. There were very few differences in volatile formation between 0% and 40% KCl application. These results suggest that K(+) substitution of Na(+) by more than 40% may significantly change profiles of volatiles in finished dry-cured bacons and therefore would result in changes in the product aroma and/or flavour. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Granular activated carbon for simultaneous adsorption and biodegradation of toxic oil sands process-affected water organic compounds.

    Science.gov (United States)

    Islam, Md Shahinoor; Zhang, Yanyan; McPhedran, Kerry N; Liu, Yang; Gamal El-Din, Mohamed

    2015-04-01

    Naphthenic acids (NAs) released into oil sands process-affected water (OSPW) during bitumen processing in Northern Alberta are problematic for oil sands industries due to their toxicity in the environment and resistance to degradation during conventional wastewater treatment processes. Granular activated carbon (GAC) has shown to be an effective media in removing biopersistent organics from wastewater using a combination of adsorption and biodegradation removal mechanisms. A simultaneous GAC (0.4 g GAC/L) adsorption and biodegradation (combined treatment) study was used for the treatment of raw and ozonated OSPW. After 28 days of batch treatment, classical and oxidized NAs removals for raw OSPW were 93.3% and 73.7%, and for ozonated OSPW were 96.2% and 77.1%, respectively. Synergetic effects of the combined treatment process were observed in removals of COD, the acid extractable fraction, and oxidized NAs, which indicated enhanced biodegradation and bioregeneration in GAC biofilms. A bacteria copy number >10(8) copies/g GAC on GAC surfaces was found using quantitative real time polymerase chain reaction after treatment for both raw and ozonated OSPW. A Microtox(®) acute toxicity test (Vibrio fischeri) showed effective toxicity removal (>95.3%) for the combined treatments. Therefore, the simultaneous GAC adsorption and biodegradation treatment process is a promising technology for the elimination of toxic OSPW NAs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Extending the Range of Organic Compounds that Can Be Destroyed Using the Process of Adsorption Coupled with Electrochemical Regeneration - 13054

    International Nuclear Information System (INIS)

    Brown, Nigel; Lodge, Mike; Hilton, Linda; Adams, Alex; Vaudey, Claire-Emilie; Toulemonde, Valerie

    2013-01-01

    The nuclear industry is not a provider of oils and solvents but uses them in motors, equipment and even in chemical processes to extract valuable products. Currently, for old and contaminated oils and solvents, techniques still exist, such as incineration, but not all the oils and solvents are compatible with this technique because the activities of some components inside the oils are too high to be accepted at the incineration facility. For these oils, an alternative technique needs to be found for treatment. A process developed for water treatment using a technique of adsorption coupled with electrochemical regeneration has been investigated to assess its capability to treat these organic wastes. One of the strengths of the process is its flexibility and adaptation to different compositions of oils. This point is important because, in the AREVA case, there are a lot of small volumes of old oils which need to be re-characterized. It takes time and money to do it especially when oils are contaminated; this is one reason why the technique is interesting to investigate. Tests have been performed with different oils coming from different sites to test the feasibility. Results demonstrate the destruction of a range of organics with regeneration energy requirements of 13.4 - 68.7 kWh/l and offer confidence for the future potential of the process. (authors)

  10. THE EVOLUTION OF COMPOUNDS IN THE AGING PROCESS OF THE DRĂGĂŞANI CABERNET SAUVIGNON WINES

    Directory of Open Access Journals (Sweden)

    Ovidiu Tiţa

    2011-02-01

    Full Text Available This paper presents the influence of raw material on wine aging and determining of the optimal duration of wine aging in oak vessels and glass vessels. The potential quality of red wines from Cabernet Sauvignon Drăgăşani is highlighted more in the aging process to oak vessels and glass vessels.

  11. Comparative Analysis of the Antioxidant Capacities and Phenolic Compounds of Oat and Buckwheat Vinegars During Production Processes.

    Science.gov (United States)

    Yu, Xiao; Yang, Mei; Dong, Jilin; Shen, Ruiling

    2018-03-01

    This study aimed to explore the dynamic changes in the antioxidant activities and phenolic acid profiles of oat and buckwheat vinegars during different production stages. The results showed that both oat and buckwheat vinegar products comparably attenuated D-galactose-induced oxidative damage in mice serum and liver, indicating no obvious dose dependence within the tested concentrations. However, oat vinegar product revealed more favorable in vitro antioxidant activities than those in buckwheat vinegar product as evaluated by 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging abilities. Moreover, the alcoholic fermentation, acetic acid fermentation and fumigating induced successive increase in DPPH radical scavenging abilities and phenolic acid contents of the fermentation substrates of oat and buckwheat vinegars. Importantly, the different fermentation processes of oat and buckwheat vinegars were accompanied by the dynamic migration and transformation of specific phenolic acids across bound, esterified and free fractions. Thus, the antioxidant activities of oat and buckwheat vinegars could be improved through targeted modulation of the generation of specific phenolic acid fractions during production processes. We had evaluated the in vitro and in vivo antioxidant activities and phenolic acid contents of oat and buckwheat vinegars, and further explored the dynamic changes of bound, esterified and free phenolic acid fractions during successive fermentation processes of oat and buckwheat vinegars. This study provided the theoretical guidance for obtaining minor grain vinegar with the optimal antioxidant activities through targeted modulation of fermentation processes. © 2018 Institute of Food Technologists®.

  12. Extending the Range of Organic Compounds that Can Be Destroyed Using the Process of Adsorption Coupled with Electrochemical Regeneration - 13054

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Nigel; Lodge, Mike; Hilton, Linda; Adams, Alex [Arvia Technology Ltd, Sci-Tech Daresbury, Keckwick Lane, Daresbury, Cheshire, WA4, 4FS (United Kingdom); Vaudey, Claire-Emilie [AREVA CL BU, AREVA BUA STMI ZAC de Courcelle 1 route de la Noue 91196 Gif-sur-Yvette (France); Toulemonde, Valerie [AREVA DRD, Tour AREVA, 1, place Jean Millier, 92084 Paris La Defense Cedex (France)

    2013-07-01

    The nuclear industry is not a provider of oils and solvents but uses them in motors, equipment and even in chemical processes to extract valuable products. Currently, for old and contaminated oils and solvents, techniques still exist, such as incineration, but not all the oils and solvents are compatible with this technique because the activities of some components inside the oils are too high to be accepted at the incineration facility. For these oils, an alternative technique needs to be found for treatment. A process developed for water treatment using a technique of adsorption coupled with electrochemical regeneration has been investigated to assess its capability to treat these organic wastes. One of the strengths of the process is its flexibility and adaptation to different compositions of oils. This point is important because, in the AREVA case, there are a lot of small volumes of old oils which need to be re-characterized. It takes time and money to do it especially when oils are contaminated; this is one reason why the technique is interesting to investigate. Tests have been performed with different oils coming from different sites to test the feasibility. Results demonstrate the destruction of a range of organics with regeneration energy requirements of 13.4 - 68.7 kWh/l and offer confidence for the future potential of the process. (authors)

  13. Removal of organic compounds from natural underground water in sorption and sono-sorption processes on selected activated carbons

    Directory of Open Access Journals (Sweden)

    Pietrzyk Andżelika

    2017-01-01

    Full Text Available The article rated removal efficiency of organic matter in the processes of sorption and sono-sorption of underground water grasped for municipal purposes. The studies were conducted in laboratory scale and verified in pilot scale at the Water Treatment Plant Tarnobrzeg-Jeziórko. In the research used granular activated carbons, ie. WD-Extra, WG-12, Norit Row 0.8 and Filtrasorb 300. The processes efficiency was evaluated on the basis of changes in the following parameters, ie.: total organic carbon (TOC, permanganate index, UV absorbance, turbidity and colour. The ultrasounds were generated by means of disintegrator Sonics&Materials VCX 130, using the sonication time of 1 and 5 minutes. The results obtained for the batch tests allowed to observe a beneficial effect of ultrasound on the efficiency of the removal of organic material in the sorption process. The combination of sonication and sorption on activated carbon increased the efficiency of the removal of organic matter by 6–37% for TOC, and 18.6–27.9% for permanganate index, depending on the sorbent used. The positive laboratory results were not confirmed in a pilot scale. In the flow conditions the sonication process did not affect the efficiency of removal of organic matter on the filter model with a bed of activated carbon.

  14. Effects of magnetic processing on electrochemical and photoelectrochemical properties of electrodes modified with nanoclusters of a phenothiazine-C{sub 60} linked compound

    Energy Technology Data Exchange (ETDEWEB)

    Yonemura, H; Yamada, S [Department of Applied Chemistry, Faculty of Engineering, Kyushu University, Fukuoka 819-0395 (Japan); Wakita, Y; Moribe, S [Department of Materials Physics and Chemistry, Graduate School of Engineering, Kyushu University, Fukuoka 819-0395 (Japan); Fujiwara, Y; Tanimoto, Y [Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan)], E-mail: yonemura@mail.cstm.kyushu-u.ac.jp

    2009-03-01

    Effects of magnetic processing on morphological, electrochemical, and photoelectrochemical properties of electrodes modified with nanoclusters of a phenothiazine-C{sub 60} linked compound with four methylene group (Ph(4)C{sub 60}) were examined in the absence and presence of magnetic processing with three different magnetic environments due to strong magnetic field. The AFM measurements indicated that the morphologies of nanostructures of Ph(4)C{sub 60} varied with magnetic enviroments as comparison with that in the absence of magnetic processing. At top position (5.6 T; - 940 T{sup 2}/m) with hypogravity, large spherical nanoclusters (60{approx}70 nm diameter) were observed as comparion with those (ca. 20 nm diameter) in the absence of magnetic processing. At middle positon (15 T; 0 T{sup 2}/m) with normal gravity, the fiber-like nanostructure was observed. At bottom position (9.8 T; + 1070T{sup 2}/m) with hypergravity, the rod-like nanostrucure was observed. The interesting results might be ascribed to the different solvent properties due to the different rates of evaporation of two solvents in the toluene-acetonitrile mixed solvent during drying process under various magnetic environments. First reduction peaks due to C{sub 60} moiety of Ph(4)C{sub 60} nanostrucures in the presence of magnetic processing at three different positions were negative-shifted as comparison with that in the absence of magnetic processing. Potential dependencies of the photocurrents of the electrodes modified with Ph(4)C{sub 60} nanostrucures in the presence of magnetic processing at three positions were also different from that in the absence of magnetic processing. The magnetic field effects in AFM, and electrochemical and photoelectrochemical measurements are most likely ascribed to the difference of the reduction potentials due to C{sub 60} clusters between the absence and presence of magnetic processing due to the morphological change of Ph(4)C{sub 60} nanostrucures.

  15. Effects of magnetic processing on electrochemical and photoelectrochemical properties of electrodes modified with nanoclusters of a phenothiazine-C60 linked compound

    International Nuclear Information System (INIS)

    Yonemura, H; Yamada, S; Wakita, Y; Moribe, S; Fujiwara, Y; Tanimoto, Y

    2009-01-01

    Effects of magnetic processing on morphological, electrochemical, and photoelectrochemical properties of electrodes modified with nanoclusters of a phenothiazine-C 60 linked compound with four methylene group (Ph(4)C 60 ) were examined in the absence and presence of magnetic processing with three different magnetic environments due to strong magnetic field. The AFM measurements indicated that the morphologies of nanostructures of Ph(4)C 60 varied with magnetic enviroments as comparison with that in the absence of magnetic processing. At top position (5.6 T; - 940 T 2 /m) with hypogravity, large spherical nanoclusters (60∼70 nm diameter) were observed as comparion with those (ca. 20 nm diameter) in the absence of magnetic processing. At middle positon (15 T; 0 T 2 /m) with normal gravity, the fiber-like nanostructure was observed. At bottom position (9.8 T; + 1070T 2 /m) with hypergravity, the rod-like nanostrucure was observed. The interesting results might be ascribed to the different solvent properties due to the different rates of evaporation of two solvents in the toluene-acetonitrile mixed solvent during drying process under various magnetic environments. First reduction peaks due to C 60 moiety of Ph(4)C 60 nanostrucures in the presence of magnetic processing at three different positions were negative-shifted as comparison with that in the absence of magnetic processing. Potential dependencies of the photocurrents of the electrodes modified with Ph(4)C 60 nanostrucures in the presence of magnetic processing at three positions were also different from that in the absence of magnetic processing. The magnetic field effects in AFM, and electrochemical and photoelectrochemical measurements are most likely ascribed to the difference of the reduction potentials due to C 60 clusters between the absence and presence of magnetic processing due to the morphological change of Ph(4)C 60 nanostrucures.

  16. Hexavalent Chromium Compounds

    Science.gov (United States)

    Learn about chromium, exposure to which can increase your risk of lung cancer and cancer of the paranasal sinuses and nasal cavity. Hexavalent chromium compounds have been used as corrosion inhibitors in a wide variety of products and processes.

  17. Numerical Simulation and Optimization of Enhanced Oil Recovery by the In Situ Generated CO2 Huff-n-Puff Process with Compound Surfactant

    Directory of Open Access Journals (Sweden)

    Yong Tang

    2016-01-01

    Full Text Available This paper presents the numerical investigation and optimization of the operating parameters of the in situ generated CO2 Huff-n-Puff method with compound surfactant on the performance of enhanced oil recovery. First, we conducted experiments of in situ generated CO2 and surfactant flooding. Next, we constructed a single-well radial 3D numerical model using a thermal recovery chemical flooding simulator to simulate the process of CO2 Huff-n-Puff. The activation energy and reaction enthalpy were calculated based on the reaction kinetics and thermodynamic models. The interpolation parameters were determined through history matching a series of surfactant core flooding results with the simulation model. The effect of compound surfactant on the Huff-n-Puff CO2 process was demonstrated via a series of sensitivity studies to quantify the effects of a number of operation parameters including the injection volume and mole concentration of the reagent, the injection rate, the well shut-in time, and the oil withdrawal rate. Based on the daily production rate during the period of Huff-n-Puff, a desirable agreement was shown between the field applications and simulated results.

  18. Processing, Valorization and Application of Bio-Waste Derived Compounds from Potato, Tomato, Olive and Cereals: A Review

    Directory of Open Access Journals (Sweden)

    Caroline Fritsch

    2017-08-01

    Full Text Available The vast and ever-growing amount of agricultural and food wastes has become a major concern throughout the whole world. Therefore, strategies for their processing and value-added reuse are needed to enable a sustainable utilization of feedstocks and reduce the environmental burden. By-products of potato, tomato, cereals and olive arise in significant amounts in European countries and are consequently of high relevance. Due to their composition with various beneficial ingredients, the waste products can be valorized by different techniques leading to economic and environmental advantages. This paper focuses on the waste generation during industrial processing of potato, tomato, cereals and olives within the European Union and reviews state-of-the-art technologies for their valorization. Furthermore, current applications, future perspectives and challenges are discussed.

  19. Simultaneous enhancement of phenolic compound degradations by Acinetobacter strain V2 via a step-wise continuous acclimation process.

    Science.gov (United States)

    Lin, Johnson; Sharma, Vikas; Milase, Ridwaan; Mbhense, Ntuthuko

    2016-06-01

    Phenol degradation enhancement of Acinetobacter strain V2 by a step-wise continuous acclimation process was investigated. At the end of 8 months, three stable adapted strains, designated as R, G, and Y, were developed with the sub-lethal concentration of phenol at 800, 1100, and 1400 mg/L, respectively, from 400 mg/L of V2 parent strain. All strains degraded phenol at their sub-lethal level within 24 h, their growth rate increased as the acclimation process continued and retained their degradation properties even after storing at -80 °C for more than 3 years. All adapted strains appeared coccoid with an ungranulated surface under electron microscope compared to typical rod-shaped parental strain V2 . The adapted Y strain also possessed superior degradation ability against aniline, benzoate, and toluene. This study demonstrated the use of long term acclimation process to develop efficient and better pollutant degrading bacterial strains with potentials in industrial and environmental bioremediation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Endocrine disruptors compounds, pharmaceuticals and personal care products in urban wastewater: implications for agricultural reuse and their removal by adsorption process.

    Science.gov (United States)

    Grassi, Mariangela; Rizzo, Luigi; Farina, Anna

    2013-06-01

    In the last years, a lot of emerging contaminants, such as, endocrine disruptors compounds (EDCs), pharmaceuticals, and personal care products (PPCPs) have been detected in wastewater. Because of their toxicity and possible adverse effects on the environment and humans, their release from urban wastewater treatment plants (UWWTPs) effluents should be minimized, particularly when a wastewater reuse for crops irrigation is expected. Many processes have been investigated for advanced treatment of UWWTP effluents as well as for emerging contaminant degradation; among these, adsorption process was successfully used to remove EDCs and PPCPs from wastewater. This article shortly reviews EDCs and PPCPs removal from UWWTP effluents by adsorption process using conventional and non-conventional adsorbents. The fate of EDCs and PPCPs in UWWTPs and the implications for agricultural wastewater reuse has been addressed too. In spite of the adsorption process looking to be a valuable alternative to other advanced technologies for the removal of emerging contaminants from wastewater, some gaps still remain to evaluate the actual feasibility at full scale. However, according to a few studies available in scientific literature on the use of both powdered activated carbon and granular activated carbon at full scale, adsorption process by activated carbon is a promising, potentially effective, and economically feasible solution for producing safe wastewater for agricultural reuse.

  1. Emissions of volatile organic compounds in the United Kingdom: a review of emission factors by species and process. Interim report

    Energy Technology Data Exchange (ETDEWEB)

    Marlowe, I.T.; Richardson, S.J.; Dowsett, R.; Passant, N.R.; Coleman, P.; Loader, A.; Giddings, T.; Warde-Jones, S.; Richardson, J.L.; Lethlean, J.; McAlister, R.

    1992-01-01

    The objective was to prepare a comprehensive review of UK VOC emissions by species and process. The purpose was to: check that no major sources have been omitted; test the relative size ranking of sources; improve the estimate of the size of each sector; sub-divide each sector so that emissions could be related to abatement options; and add speciated data. Best emission estimates are provided for the following: solvent use, oil industry, chemical industry, stationary combustion, food industry, iron and steel, waste disposal and agriculture. 9 refs., 20 tabs.

  2. Louisiana SIP: LAC 33:III Ch 21 Subchap J, 2147--Limiting Volatile Organic Compound (VOC) Emissions from Reactor Processes and Distillation Operations in Synthetic Organic Chemical manufacturing Industry (SOCMI); SIP effective 1998-02-02 (LAc74) to more..

    Science.gov (United States)

    Louisiana SIP: LAC 33:III Ch 21 Subchap J, 2147--Limiting Volatile Organic Compound (VOC) Emissions from Reactor Processes and Distillation Operations in Synthetic Organic Chemical manufacturing Industry (SOCMI); SIP effective 1998-02-02 (LAc74) more...

  3. Louisiana SIP: LAC 33:III Ch 2147. Limiting Volatile Organic Compound (VOC) Emissions from Reactor Processes and Distillation Operations in Synthetic Organic Chemical manufacturing Industry (SOCMI); SIP effective 2011-08-04 (LAd34) to 2017-09-27

    Science.gov (United States)

    Louisiana SIP: LAC 33:III Ch 2147. Limiting Volatile Organic Compound (VOC) Emissions from Reactor Processes and Distillation Operations in Synthetic Organic Chemical manufacturing Industry (SOCMI); SIP effective 2011-08-04 (LAd34) to 2017-09-27

  4. Equipment Leaks of Volatile Organic Compounds From Onshore Natural Gas Processing Plants for Which Construction, Reconstruction, or Modification Commenced After January 20, 1984, and on or Before August 23, 2011: New Source Performance Standards (NSPS)

    Science.gov (United States)

    Learn about the NSPS regulation for equipment leaks of Volatile Organic Compounds (VOC) from onshore natural gas processing plants by reading the rule summary, rule history, federal register citations, and the code of federal regulations

  5. Control of a metalorganic chemical vapor deposition process for improved composition and thickness precision in compound semiconductors

    Science.gov (United States)

    Gaffney, Monique Suzanne

    1998-11-01

    Metalorganic chemical vapor deposition (MOCVD) is a process used to manufacture electronic and optoelectronic devices that has traditionally lacked real-time growth monitoring and control. Controlling the growth rate and composition using the existing sensors, as well as advanced monitoring systems developed in-house, is shown to improve device quality. Specific MOCVD growth objectives are transformed into controller performance goals. Group III bubbler concentration variations, which perturb both growth rate and composition precision, are identified to be the primary disturbances. First a feed forward control system was investigated, which used an ultrasonic concentration monitor, located upstream in the process. This control strategy resulted in improved regulation of the gallium delivery rate by cancelling the sensed gallium bubbler concentration disturbances via the injection mass flow controller. The controller performance is investigated by growing GaInAs/InP superlattices. Results of growths performed under normal operating conditions and also under large perturbations include X-ray diffraction from the samples as well as real-time sensor signal data. High quality superlattices that display up to eight orders of satellite peaks are obtained under the feed forward compensation scheme, demonstrating improved layer-to-layer reproducibility of thickness and composition. The success of the feed forward control demonstration led to the development of a more complex downstream feedback control system. An ultraviolet absorption monitor was fabricated and retrofitted as a feedback control signal. A control-oriented model of the downstream process was developed for the feedback controller synthesis. Although challenged with both the photolysis and multi-gas detection issues common to UV absorption monitors, closed loop control with the UV sensor was performed and proved to be an effective method of disturbance rejection. An InP/GaInAs test structure was grown under

  6. High-throughput fabrication of micrometer-sized compound parabolic mirror arrays by using parallel laser direct-write processing

    International Nuclear Information System (INIS)

    Yan, Wensheng; Gu, Min; Cumming, Benjamin P

    2015-01-01

    Micrometer-sized parabolic mirror arrays have significant applications in both light emitting diodes and solar cells. However, low fabrication throughput has been identified as major obstacle for the mirror arrays towards large-scale applications due to the serial nature of the conventional method. Here, the mirror arrays are fabricated by using a parallel laser direct-write processing, which addresses this barrier. In addition, it is demonstrated that the parallel writing is able to fabricate complex arrays besides simple arrays and thus offers wider applications. Optical measurements show that each single mirror confines the full-width at half-maximum value to as small as 17.8 μm at the height of 150 μm whilst providing a transmittance of up to 68.3% at a wavelength of 633 nm in good agreement with the calculation values. (paper)

  7. Impact of high pressure processing on color, bioactive compounds, polyphenol oxidase activity, and microbiological attributes of pumpkin purée.

    Science.gov (United States)

    González-Cebrino, Francisco; Durán, Rocío; Delgado-Adámez, Jonathan; Contador, Rebeca; Bernabé, Rosario Ramírez

    2016-04-01

    Physicochemical parameters, bioactive compounds' content (carotenoids and total phenols), total antioxidant activity, and enzymatic activity of polyphenol oxidase (PPO) were evaluated after high pressure processing (HPP) on a pumpkin purée (cv. 'Butternut'). Three pressure levels (400, 500, and 600 MPa) were combined with three holding times (200, 400, and 600 s). The applied treatments reduced the levels of total aerobic mesophilic (TAM), total psychrophilic and psychrotrophic bacteria (TPP), and molds and yeasts (M&Y). All applied treatments did not affect enzymatic activity of PPO. Pressure level increased CIE L* values, which could enhance the lightness perception of high pressure (HP)-treated purées. No differences were found between the untreated and HP-treated purées regarding total phenols and carotenoids content (lutein, α-carotene, and β-carotene) and total antioxidant activity. HPP did not affect most quality parameters and maintained the levels of bioactive compounds. However, it did not achieve the complete inhibition of PPO, which could reduce the shelf-life of the pumpkin purée. © The Author(s) 2015.

  8. Evaluation of processed green and ripe mango peel and pulp flours (Mangifera indica var. Chokanan) in terms of chemical composition, antioxidant compounds and functional properties.

    Science.gov (United States)

    Abdul Aziz, Noor Aziah; Wong, Lee Min; Bhat, Rajeev; Cheng, Lai Hoong

    2012-02-01

    Mango is a highly perishable seasonal fruit and large quantities are wasted during the peak season as a result of poor postharvest handling procedures. Processing surplus mango fruits into flour to be used as a functional ingredient appears to be a good preservation method to ensure its extended consumption. In the present study, the chemical composition, bioactive/antioxidant compounds and functional properties of green and ripe mango (Mangifera indica var. Chokanan) peel and pulp flours were evaluated. Compared to commercial wheat flour, mango flours were significantly low in moisture and protein, but were high in crude fiber, fat and ash content. Mango flour showed a balance between soluble and insoluble dietary fiber proportions, with total dietary fiber content ranging from 3.2 to 5.94 g kg⁻¹. Mango flours exhibited high values for bioactive/antioxidant compounds compared to wheat flour. The water absorption capacity and oil absorption capacity of mango flours ranged from 0.36 to 0.87 g kg⁻¹ and from 0.18 to 0.22 g kg⁻¹, respectively. Results of this study showed mango peel flour to be a rich source of dietary fiber with good antioxidant and functional properties, which could be a useful ingredient for new functional food formulations. Copyright © 2011 Society of Chemical Industry.

  9. Study of the behavior of the compound Mg2Ni0.5Co0.5 front to hydriding process

    International Nuclear Information System (INIS)

    Martinez, C; Ordonez, S; Serafini, D; Guzman, D; Bustos, O

    2012-01-01

    This paper study the behavior of the compound Mg 2 Ni 0,5 Co 0,5 during the hydriding process. Elemental powders of Mg, Ni and Co, with an atomic ratio of 2:0,5:0,5 were mechanically alloyed using a high energy mill SPEX 8000D for 36h. The amorphous and crystalline structure of the samples was characterized through X-ray diffraction The hydriding process was performed by the volumetric technique Sievert at 90 o C and a pressure of 20 bar H 2 . The desorption process was evaluated by differential scanning calorimetry. Based on the results we can conclude that the amorphous structure absorbs more hydrogen, reaching a maximum of 3.6 wt% H2, besides the incorporation of cobalt act as catalyst for the absorption of H2 obtaining values higher than those reported in the Mg-Ni system amorphous state. The desorption process is influenced by the type of structure that presents the alloy

  10. Intramolecular Diels–Alder reaction as a key step in tandem or sequential processes: a versatile tool for the synthesis of fused and bridged bicyclic or polycyclic compounds.

    Digital Repository Service at National Institute of Oceanography (India)

    Parvatkar, P.T.; Kadam, H.K.; Tilve, S.G.

    This review summarizes the recent examples of tandem or sequential reactions used for the last 10 years for the synthesis of fused and bridged bicyclic or polycyclic compounds with IMDA cycloaddition as the key means to access these compounds...

  11. Organolanthanoid compounds

    International Nuclear Information System (INIS)

    Schumann, H.

    1984-01-01

    Up to little more than a decade ago organolanthanoid compounds were still a curiosity. Apart from the description of an isolated number of cyclopentadienyl and indenyl derivatives, very few significant contributions had been made to this interesting sector of organometallic chemistry. However, subsequent systematic studies using modern preparative and analytical techniques, together with X-ray single crystal structure determinations, enabled the isolation and characterization of a large number of very interesting homoleptic and heteroleptic compounds in which the lanthanoid is bound to hydrogen, to substituted or unsubstituted cyclopentadienyl groups, to allyl or alkynyl groups, or even to phosphorus ylides, trimethylsilyl, and carbonylmetal groups. These compounds, which are all extremely sensitive to oxygen and water, open up new possibilities in the field of catalysis and have great potential in organic synthesis - as recent studies with pentamethylcyclopentadienyl derivatives, organolanthanoid(II) compounds, and hexamethyllanthanoid complexes have already shown. (orig.) [de

  12. Catalytic properties of niobium compounds

    International Nuclear Information System (INIS)

    Tanabe, K.; Iizuka, T.

    1983-04-01

    The catalytic activity and selectivity of niobium compounds including oxides, salts, organometallic compounds and others are outlined. The application of these compounds as catalysts to diversified reactions is reported. The nature and action of niobium catalysts are characteristic and sometimes anomalous, suggesting the necessity of basic research and the potential use as catalysts for important processes in the chemical industry. (Author) [pt

  13. Homogeneous (Cu, Ni)6Sn5 intermetallic compound joints rapidly formed in asymmetrical Ni/Sn/Cu system using ultrasound-induced transient liquid phase soldering process.

    Science.gov (United States)

    Li, Z L; Dong, H J; Song, X G; Zhao, H Y; Tian, H; Liu, J H; Feng, J C; Yan, J C

    2018-04-01

    Homogeneous (Cu, Ni) 6 Sn 5 intermetallic compound (IMC) joints were rapidly formed in asymmetrical Ni/Sn/Cu system by an ultrasound-induced transient liquid phase (TLP) soldering process. In the traditional TLP soldering process, the intermetallic joints formed in Ni/Sn/Cu system consisted of major (Cu, Ni) 6 Sn 5 and minor Cu 3 Sn IMCs, and the grain morphology of (Cu, Ni) 6 Sn 5 IMCs subsequently exhibited fine rounded, needlelike and coarse rounded shapes from the Ni side to the Cu side, which was highly in accordance with the Ni concentration gradient across the joints. However, in the ultrasound-induced TLP soldering process, the intermetallic joints formed in Ni/Sn/Cu system only consisted of the (Cu, Ni) 6 Sn 5 IMCs which exhibited an uniform grain morphology of rounded shape with a remarkably narrowed Ni concentration gradient. The ultrasound-induced homogeneous intermetallic joints exhibited higher shear strength (61.6 MPa) than the traditional heterogeneous intermetallic joints (49.8 MPa). Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Removal of selected nitrogenous heterocyclic compounds in biologically pretreated coal gasification wastewater (BPCGW) using the catalytic ozonation process combined with the two-stage membrane bioreactor (MBR).

    Science.gov (United States)

    Zhu, Hao; Han, Yuxing; Ma, Wencheng; Han, Hongjun; Ma, Weiwei

    2017-12-01

    Three identical anoxic-aerobic membrane bioreactors (MBRs) were operated in parallel for 300 consecutive days for raw (R 1 ), ozonated (R 2 ) and catalytic ozonated (R 3 ) biologically pretreated coal gasification wastewater (BPCGW) treatment. The results demonstrated that catalytic ozonation process (COP) applied asa pretreatment remarkably improved the performance of the unsatisfactory single MBR. The overall removal efficiencies of COD, NH 3 -N and TN in R 3 were 92.7%, 95.6% and 80.6%, respectively. In addition, typical nitrogenous heterocyclic compounds (NHCs) of quinoline, pyridine and indole were completely removed in the integrated process. Moreover, COP could alter sludge properties and reshape microbial community structure, thus delaying the occurrence of membrane fouling. Finally, the total cost for this integrated process was estimated to be lower than that of single MBR. The results of this study suggest that COP is a good option to enhance pollutants removal and alleviate membrane fouling in the MBR for BPCGW treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Depth resolved lattice-charge coupling in epitaxial BiFeO3 thin film

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyeon Jun; Lee, Sung Su; Kwak, Jeong Hun; Kim, Young-Min; Jeong, Hu Young; Borisevich, Albina Y.; Lee, Su Yong; Noh, Do Young; Kwon, Owoong; Kim, Yunseok; Jo, Ji Young

    2016-12-01

    For epitaxial films, a critical thickness (tc) can create a phenomenological interface between a strained bottom layer and a relaxed top layer. Here, we present an experimental report of how the tc in BiFeO3 thin films acts as a boundary to determine the crystalline phase, ferroelectricity, and piezoelectricity in 60 nm thick BiFeO3/SrRuO3/SrTiO3 substrate. We found larger Fe cation displacement of the relaxed layer than that of strained layer. In the time-resolved X-ray microdiffraction analyses, the piezoelectric response of the BiFeO3 film was resolved into a strained layer with an extremely low piezoelectric coefficient of 2.4 pm/V and a relaxed layer with a piezoelectric coefficient of 32 pm/V. The difference in the Fe displacements between the strained and relaxed layers is in good agreement with the differences in the piezoelectric coefficient due to the electromechanical coupling.

  16. Low temperature magneto-dielectric measurements on BiFeO3 lightly substituted by cobalt

    International Nuclear Information System (INIS)

    Ray, J.; Biswal, A. K.; Vishwakarma, P. N.

    2015-01-01

    Dielectric and magnetodielectric measurements are done on BiFe 1−x Co x O 3 : x = 0, 0.01, and 0.02 in the temperature range 70–300 K and up to magnetic field 1.3 T. The dielectric data are well described by Haverliak–Negami expression plus an additional term for the Maxwell Wagner (MW) type relaxations, whose contribution is dominant near room temperature. The parameters obtained from the fitting of data using the above mentioned expression, suggest slowing down of relaxation and approach towards ideal Debye type relaxations, as the temperature is lowered. The dielectric relaxations obey polaronic variable range hopping model with distinct activation energies (E a ) in the extrinsic (6.67T 3/4  meV) and intrinsic (2.88T 3/4  meV) regions for the parent sample (x = 0), and thus a distinct transition from extrinsic to intrinsic behavior is seen at 215 K while lowering the temperature. This distinct transition is missing for Co substituted samples probably due to the extrinsic region values of E a (3.42T 3/4  meV and 2.42T 3/4  meV for x = 0.01 and 0.02, respectively) comparable to that of the intrinsic region (see x = 0). The magnetodielectric measurement shows positive magnetodielectricity (MD) in the intrinsic region (T < 215 K for x = 0) and negative MD in the extrinsic region (T > 215 K for x = 0). The extrinsic region is found to be dominated by MW and magnetoresistance effects, whereas MD in intrinsic regions is due to the spin reorientation transitions. The Co substitution is found to increase the extrinsic and non-Debye contributions to dielectricity, which becomes so large that no spin reorientation transitions are seen in x = 0.02 sample. The pyroelectric active region in x = 0 is found to be dominated by the diffusive behavior having contribution of the form ω −0.5

  17. Magnetoelectric properties of Co-doped BiFeO3 nanoparticles

    Science.gov (United States)

    Shrimali, V. G.; Rathod, K. N.; Dhruv, Davit; Zankat, Alpa; Sagapariya, Khushal; Solanki, Sapana; Solanki, P. S.; Shah, N. A.; Kataria, B. R.

    2018-05-01

    The magnetoelectric (ME) properties of sol-gel grown BiFe0.95Co0.05O3 (BFCO) nanoceramics, with different sizes, were investigated at room-temperature. X-ray diffraction (XRD) measurement was performed to investigate structural properties of the samples understudy. Magnetic field-dependent dielectric permittivity has been systematically investigated in the frequency range of 20 Hz to 1 MHz. To ensure the origin of magnetodielectric response, the magnetoimpedance (MI) spectroscopy was adopted using equivalent circuit model. The a.c. conductivity was found to obey the Jonscher’s universal power law. The modifications in spiral spin structure in the BFCO nanoparticles with size less than ˜62 nm significantly affect the ME coupling parameters.

  18. Neutron diffraction studies on cobalt substituted BiFeO3

    Science.gov (United States)

    Ray, J.; Biswal, A. K.; Acharya, S.; Babu, P. D.; Siruguri, V.; Vishwakarma, P. N.

    2013-02-01

    A dilute concentration of single phase Cobalt substituted Bismuth ferrite, BiFe1-XCoXO3; (x=0, 0.02) is prepared by sol-gel auto combustion method. Room temperature neutron diffraction patterns show no change in the crystal and magnetic structure upon cobalt doping. The calculation of magnetic moments shows 3.848 μB for Fe+ and 2.85 μB for Co3+. The cobalt is found to be in intermediate spin state.

  19. Spatially Resolved Large Magnetization in Ultrathin BiFeO3

    KAUST Repository

    Guo, Er-Jia; Petrie, Jonathan R.; Roldan, Manuel A.; Li, Qian; Desautels, Ryan D.; Charlton, Timothy; Herklotz, Andreas; Nichols, John; van Lierop, Johan; Freeland, John W.; Kalinin, Sergei V.; Lee, Ho Nyung; Fitzsimmons, Michael R.

    2017-01-01

    . The results show the enhanced net magnetic moment in BFO from the LSMO/BFO interface extends 3-4 unit cells into BFO. The interior part of a thicker BFO layer has a much smaller magnetization, suggesting it still keeps the small canted AFM state. The results

  20. Novel electrical conductivity properties in Ca-doped BiFeO3 nanoparticles

    International Nuclear Information System (INIS)

    Wang, X.; Wang, S. Y.; Liu, W. F.; Xi, X. J.; Zhang, H.; Guo, F.; Xu, X. L.; Li, M.; Liu, L.; Zhang, C.; Li, X.; Yang, J. B.

    2015-01-01

    The charge defective structure in Bi 1−x Ca x FeO 3 (CBFO, x = 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3) nanoparticles (NPs) ranging from 140 to 25 nm as well as their relations to band gap and leakage current behavior are investigated. It is demonstrated that Ca doping effectively narrows the band gap from ∼2.16 to ∼2.02 eV, due to the appearance and accumulation of oxygen vacancy. Subsequently, enhanced electrical conductivity was obtained in these CBFO NPs, which leads to the appearance of a distinct threshold switching behavior in Ca-doped BFO NPs with higher conductivity at room temperature. Possible mechanisms for Ca doping effects on the electric conduction were discussed upon the interplay of NPs’ size effect and mobile charged defects on the basis of reduced particle size and the increased density of oxygen vacancy analyzed through X-ray photoelectron spectrum

  1. Fabrication and characterization of nanostructured Ba-doped BiFeO3 porous ceramics

    Directory of Open Access Journals (Sweden)

    Mostafavi E.

    2016-03-01

    Full Text Available Nanostructured barium doped bismuth ferrite, Bi₀.₈Ba₀.₂FeO₃ porous ceramics with a relatively high magnetic coercivity was fabricated via sacrificial pore former method. X-ray diffraction results showed that 20 wt.% Ba doping induces a structural phase transition from rhombohedral to distorted pseudo-cubic structure in the final porous samples. Moreover, utilizing Bi₀.₈Ba₀.₂FeO₃ as the starting powder reduces the destructive interactions between the matrix phase and pore former, leading to an increase in stability of bismuth ferrite phase in the final porous ceramics. Urea-derived Bi₀.₈Ba₀.₂FeO₃ porous ceramic exhibits density of 4.74 g/cm³ and porosity of 45 % owing the uniform distribution of interconnected pores with a mean pore size of 7.5 μm. Well defined nanostructured cell walls with a mean grain size of 90 nm were observed in the above sample, which is in a good accordance with the grain size obtained from BET measurements. Saturation magnetization decreased from 2.31 in the Bi₀.₈Ba₀.₂FeO₃ compact sample to 1.85 A m²/kg in urea-derived Bi₀.₈Ba₀.₂FeO₃ porous sample; moreover, coercivity increased from 284 to 380 kA/m.

  2. Relaxor behaviour and dielectric properties of BiFeO3 doped Ba ...

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... Ba1−Bi(Ti0.9Zr0.1)1−FeO3 ( = 0–0.075) ceramics are prepared using a conventional solid state reaction method. X-ray diffraction shows the presence of a single phase. Addition of Bi3+ and Fe3+ strongly influences the crystal structure and dielectric properties of the ceramics. The evolution from a ...

  3. Size effect study in magnetoelectric BiFeO3 system

    Indian Academy of Sciences (India)

    ... for phase determination and lattice parameter calculations (figure 1). The coherently diffracting domain size dXRD is calculated from X- ray line broadening using Scherrer's formula. Scanning electron microscopy (SEM) is used to find out grain size and morphology (figure 2). Differential scanning calorimeter (DSC). 1028.

  4. Process Challenges in Compound Semiconductors.

    Science.gov (United States)

    1988-08-01

    dimension in GaAs quantum well wires and boxes. Appl. Phys. Lett. 49:1275. Cox, H. M., S. G. Hummel, and V. G. Keramidas. 1986. Vapor levitation epitaxy...improved materials, and new device concepts. Many of these involve the fabrication of multilayer structures for quantum well lasers and detectors...dimensions, where quantum effects dominate, has already led to a number of conceptual breakthroughs for new devices and circuits. Such breakthroughs are

  5. Process for removing a mixture containing iodine and alkyl iodine compounds from a gas phase or aqueous solution with ion-exchange resins

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, H; Mizuuchi, A; Yokoyama, F

    1968-10-04

    Iodine and alkyl iodine compounds are removed from a gas phase or aqueous solution containing salts, iodine and iodine compounds, such as the ambient gas in a reactor, if an accident should occur. The process comprises contacting the phase or solution: (a) with a hydrogen type strongly acidic cationic exchange resin, (b) with an anionic exchange resin containing quarternary ammonium and (c) with an anionic exchange resin containing free basic type tertiary amine, in this order or by reversing the order of the two anionic exchange resins. Although no problems arise in the liquid phase reaction, the ion-exchange resins in the gas phase reaction are desired in the moist state in order to stable maintain the migration speed of the materials to be removed regardless of the relative humidity of the amibent gas. In example I, Amberlite IRA-900 of 200 mm thickness as the lowermost bed, Amberlite IRA93 of 200 mm thickness as the middle bed and Amberlite 200 of 200 mm thickness as the uppermost bed were filled respectively, in a methacrylate resin cylinder with an inner diameter of 25 mm. A solution containing 15.9 mg/1 of iodine, 41.2 mg/1 of methyl iodide and 550 mg/1 of sodium carbonate flows at a rate of 15 liter/hr downward through the beds. As a result of testing, no iodine, iodine ions, iodic acid ions and methyl iodine were detected. The amount of water the beds could treat was 60 times the total quantity of the filled resins.

  6. Novel Tandem Biotransformation Process for the Biosynthesis of a Novel Compound, 4-(2,3,5,6-Tetramethylpyrazine-1)-4′-Demethylepipodophyllotoxin▿

    Science.gov (United States)

    Tang, Ya-Jie; Zhao, Wei; Li, Hong-Mei

    2011-01-01

    According to the structure of podophyllotoxin and its structure-function relationship, a novel tandem biotransformation process was developed for the directional modification of the podophyllotoxin structure to directionally synthesize a novel compound, 4-(2,3,5,6-tetramethylpyrazine-1)-4′-demethylepipodophyllotoxin (4-TMP-DMEP). In this novel tandem biotransformation process, the starting substrate of podophyllotoxin was biotransformed into 4′-demethylepipodophyllotoxin (product 1) with the demethylation of the methoxyl group at the 4′ position by Gibberella fujikuroi SH-f13, which was screened out from Shennongjia prime forest humus soil (Hubei, China). 4′-Demethylepipodophyllotoxin (product 1) was then biotransformed into 4′-demethylpodophyllotoxone (product 2) with the oxidation of the hydroxyl group at the 4 position by Alternaria alternata S-f6, which was screened out from the gathered Dysosma versipellis plants in the Wuhan Botanical Garden, Chinese Academy of Sciences. Finally, 4′-demethylpodophyllotoxone (product 2) and ligustrazine were linked with a transamination reaction to synthesize the target product 4-TMP-DMEP (product 3) by Alternaria alternata S-f6. Compared with podophyllotoxin (i.e., a 50% effective concentration [EC50] of 529 μM), the EC50 of 4-TMP-DMEP against the tumor cell line BGC-823 (i.e., 0.11 μM) was significantly reduced by 5,199 times. Simultaneously, the EC50 of 4-TMP-DMEP against the normal human proximal tubular epithelial cell line HK-2 (i.e., 0.40 μM) was 66 times higher than that of podophyllotoxin (i.e., 0.006 μM). Furthermore, compared with podophyllotoxin (i.e., log P = 0.34), the water solubility of 4-TMP-DMEP (i.e., log P = 0.66) was significantly enhanced by 94%. For the first time, the novel compound 4-TMP-DMEP with superior antitumor activity was directionally synthesized from podophyllotoxin by the novel tandem biotransformation process developed in this work. PMID:21398491

  7. Multipurpose Compound

    Science.gov (United States)

    1983-01-01

    Specially formulated derivatives of an unusual basic compound known as Alcide may be the answer to effective treatment and prevention of the disease bovine mastitis, a bacterial inflammation of a cow's mammary gland that results in loss of milk production and in extreme cases, death. Manufactured by Alcide Corporation the Alcide compound has killed all tested bacteria, virus and fungi, shortly after contact, with minimal toxic effects on humans or animals. Alcide Corporation credits the existence of the mastitis treatment/prevention products to assistance provided the company by NERAC, Inc.

  8. Polymer compound

    NARCIS (Netherlands)

    1995-01-01

    A Polymer compound comprising a polymer (a) that contains cyclic imidesgroups and a polymer (b) that contains monomer groups with a 2,4-diamino-1,3,5-triazine side group. According to the formula (see formula) whereby themole percentage ratio of the cyclic imides groups in the polymer compoundwith

  9. Mesoionic Compounds

    Indian Academy of Sciences (India)

    Organic Chemistry. Kamatak University,. Dharwad. Her research interests are synthesis, reactions and synthetic utility of sydnones. She is currently working on electrochemical and insecticidal/antifungal activities for some of these compounds. Keywords. Aromaticity, mesoionic hetero- cycles, sydnones, tandem re- actions.

  10. Semiconducting III-V compounds

    CERN Document Server

    Hilsum, C; Henisch, Heinz R

    1961-01-01

    Semiconducting III-V Compounds deals with the properties of III-V compounds as a family of semiconducting crystals and relates these compounds to the monatomic semiconductors silicon and germanium. Emphasis is placed on physical processes that are peculiar to III-V compounds, particularly those that combine boron, aluminum, gallium, and indium with phosphorus, arsenic, and antimony (for example, indium antimonide, indium arsenide, gallium antimonide, and gallium arsenide).Comprised of eight chapters, this book begins with an assessment of the crystal structure and binding of III-V compounds, f

  11. Review of the anticarcinogenic properties and other health benefits of tomato compounds lycopene and tomatine in pure form and in fresh and processed tomatoes

    Science.gov (United States)

    Tomatoes produce the bioactive compounds the red pigment lycopene and the glycoalkaloid a-tomatine that are reported to have potential health-promoting effects in animals and humans but our understanding of the roles of these compounds in the diet is incomplete. This review surveys and interprets t...

  12. Influence of grain size and upper critical magnetic field on global pinning force of bronze-processed Nb/sub 3/Sn compound

    International Nuclear Information System (INIS)

    Ochiai, S.; Osamura, K.

    1986-01-01

    In order to know the dependency of global pinning force of Nb/sub 3/Sn compound on grain size and upper critical magnetic field, the global pinning force was measured at 3-15 T using bronze-processed multifilamentary composites. The grain size and upper critical magnetic field were varied by two types of annealing treatment: one is the isothermal annealing at 873, 973 and 1073 K up to 1730 ks and another is the two-stage annealing (low temperature annealing to form fine grains at 873 K for 1730 ks + high temperature annealing to raise upper critical magnetic field at 1073 K up to 18 ks). In the case of isothermal annealing treatment, both of grain size and upper critical magnetic field increased with increasing annealing temperature and time except for the annealing treatments at high temperature for prolonged times. In the case of two-stage annealing, both of them increased with second stage annealing time. The increase in grain size led to decrease in the pinning force but the increase in upper critical magnetic field to increase in it. From the analysis of the present data based on the Suenaga's speculation concerning with the density of pinning site and the Kramer's equation, it was suggested that the pinning force is, to a first approximation, proportional to the product of inverse grain size and (1-h)/sup 2/h/sup 1/2/ where h is the reduced magnetic field

  13. Valorization of Olive Mill Wastewater by Membrane Processes to Recover Natural Antioxidant Compounds for Cosmeceutical and Nutraceutical Applications or Functional Foods.

    Science.gov (United States)

    Alfano, Alberto; Corsuto, Luisana; Finamore, Rosario; Savarese, Maria; Ferrara, Filomena; Falco, Salvatore; Santabarbara, Giuseppe; De Rosa, Mario; Schiraldi, Chiara

    2018-05-23

    Olive oil boasts numerous health benefits due to the high content of the monounsaturated fatty acid (MUFA) and functional bioactives including tocopherols, carotenoids, phospholipids, and polyphenolics with multiple biological activities. Polyphenolic components present antioxidant properties by scavenging free radicals and eliminating metabolic byproducts of metabolism. The objective of this research project was to recover the biologically active components rich in polyphenols, which include treatment of olive oil mills wastewater, and, at the same time, to remove the pollutant waste component resulting from the olive oil manufacturing processes. With specific focus on using technologies based on the application of ultra and nanofiltration membranes, the polyphenols fraction was extracted after an initial flocculation step. The nano-filtration permeate showed a reduction of about 95% of the organic load. The polyphenols recovery after two filtration steps was about 65% w / v . The nanofiltration retentate, dried using the spray dryer technique, was tested for cell viability after oxidative stress induction on human keratinocytes model in vitro and an improved cell reparation in the presence of this polyphenolic compound was demonstrated in scratch assays assisted through time lapse video-microscopy. The polyphenols recovered from these treatments may be suitable ingredients in cosmeceuticals and possibly nutraceutical preparations or functional foods.

  14. Formation of brominated disinfection byproducts from natural organic matter isolates and model compounds in a sulfate radical-based oxidation process

    KAUST Repository

    Wang, Yuru; Le Roux, Julien; Zhang, Tao; Croue, Jean-Philippe

    2014-01-01

    A sulfate radical-based advanced oxidation process (SR-AOP) has received increasing application interest for the removal of water/wastewater contaminants. However, limited knowledge is available on its side effects. This study investigated the side effects in terms of the production of total organic bromine (TOBr) and brominated disinfection byproducts (Br-DBPs) in the presence of bromide ion and organic matter in water. Sulfate radical was generated by heterogeneous catalytic activation of peroxymonosulfate. Isolated natural organic matter (NOM) fractions as well as low molecular weight (LMW) compounds were used as model organic matter. Considerable amounts of TOBr were produced by SR-AOP, where bromoform (TBM) and dibromoacetic acid (DBAA) were identified as dominant Br-DBPs. In general, SR-AOP favored the formation of DBAA, which is quite distinct from bromination with HOBr/OBr- (more TBM production). SR-AOP experimental results indicate that bromine incorporation is distributed among both hydrophobic and hydrophilic NOM fractions. Studies on model precursors reveal that LMW acids are reactive TBM precursors (citric acid > succinic acid > pyruvic acid > maleic acid). High DBAA formation from citric acid, aspartic acid, and asparagine was observed; meanwhile aspartic acid and asparagine were the major precursors of dibromoacetonitrile and dibromoacetamide, respectively.

  15. The effect of inactivated yeast-based products on the process of wine aging, phenolic compounds and sensory characteristics of red wine Prokupac

    Directory of Open Access Journals (Sweden)

    Malićanin Marko

    2017-01-01

    Full Text Available Keeping of red wine in bottles is very important for its maturation and quality. However, there are numerous changes that happen during that period, usually caused by oxidative processes and changes in structure and content of polyphenolic compounds. The goal of this study was to determine the effects of Inactivated dry yeast (IDY products on aging, phenolics content, colour stability and sensory characteristics of red wine Prokupac (Serbian autochthonous variety. The treatment of wine was done by 3 different IDYP (Lallemand, Canada: Optimum White, Opti Less and Noblesse, applied as 0.2 g/L and 0.4 g /L during 15 days. Subsequently, wine clarification was done, followed by filtration and bottling. Untreated wines were used for comparison. Wine was subjected to accelerated aging (10 days at 55 ° C and also to normal aging conditions during one year. To determine the influence of IDYP following parameters were monitored: dissolved O2, free and total SO2, sugar free extract, content of total phenolics, flavonoids, flavan-3-ols and anthocyanins, percent of polymeric color, color tint, color intensity and sensory characteristics (Panel method. The obtained results clearly show that IDY products are good scavengers of oxygen and have a positive impact on wine quality preservation and its organoleptic characteristics. However, a slight decrease of polyphenols content was detected.

  16. The role of the surrounding polarity on the phototautomerization process in a diazaaromatic compound: An UV–vis and NMR study

    Energy Technology Data Exchange (ETDEWEB)

    Reyman, Dolores, E-mail: dolores.reyman@uam.es [Departamento de Química Física Aplicada, Universidad Autónoma de Madrid, E-28049 (Spain); Montoro, Teresa [EUIT Forestales, Universidad Politécnica de Madrid, 28040 Madrid (Spain); Viñas, Montserrat H. [Departamento de Sistemas Inteligentes Aplicados, Universidad Politécnica de Madrid, E-28031 Madrid (Spain); Díaz-Oliva, Cristina [Departamento de Química Física Aplicada, Universidad Autónoma de Madrid, E-28049 (Spain); Tardajos, Gloria [Departamento de Química Física I, Universidad Complutense de Madrid, E-28040 Madrid (Spain)

    2014-04-15

    Fluorescence steady-state and decay measurements of the azaaromatic derivative norharmane were obtained in solvents with different polarities: dichloromethane (DCM) and acetonitrile (ACN), at different temperatures, in the absence and the presence of a donor/acceptor hydrogen bond such as acetic acid. 2D NOESY experiments confirmed that this compound forms a hydrogen-bonding cyclic complex with acetic acid in the ground state. This complex induced a phototautomeric equilibrium, which produced new emission bands at 400 and 500 nm. This tautomeric process was established only in the first excited state via a concerted proton–electron transfer. Indeed, the cyclic complex formed in the ground state evolved to a like-cation upon cooling from room temperature to 225 K, and a new emission band at 450 nm is observed. The fluorescence decay times confirmed these results. -- Highlights: • 2D NOESY experiments confirm that norharmane forms a hydrogen-bonding cyclic complex with acetic acid molecules • This complex induces a phototautomeric equilibrium via a concerted proton–electron transfer. • A monotonous transformation of the type OH···N→ O{sup δ−}···H···N{sup δ+}→ O{sup −}···HN{sup +} occurs when the temperature is lowered. • Resulting from this transformation, the four fluorescence bands observed at room temperature are converted into a single fluorescence band at 225 K.

  17. Simulation of the precipitation process of ordered intermetallic compounds in binary and ternary Ni-Al-based alloys by the phase-field model

    International Nuclear Information System (INIS)

    Hou Hua; Zhao Yuhong; Zhao Yuhui

    2009-01-01

    With the microscopic phase-field model, atomic-scale computer simulation programs for the precipitation mechanism of the ordered intermetallic compound γ' in binary Ni-15.5 at.%Al alloy, θ and γ' in ternary Ni 75 Al x V 25-x alloys were worked out based on the microscopic diffusion equation and non-equilibrium free energy. The simulation can be applied to the whole precipitation process and composition range. A prior assumptions on the new phase structure or transformation path was unnecessary, the possible non-equilibrium phases, atomic clustering and ordering could be described automatically, and atomic images, order parameters and volume fractions of precipitates were obtained. Computer simulation was performed systematically on the precipitation mechanism, precipitation sequence of θ and γ' in complicated system with ordering and clustering simultaneously. Through the simulated atomic images and chemical order parameters of precipitates, we can explain the complex precipitation mechanisms of θ (Ni 3 V) and γ' (Ni 3 Al) ordered phases. For the binary alloy, the precipitation mechanism of γ' phase has the characteristic of both non-classical nucleation and growth (NCNG) and congruent ordering and spinodal decomposition (COSD). For the ternary alloys, the precipitation characteristic of γ' phase transforms from NCNG to COSD gradually, otherwise, the precipitation characteristic of θ phase transforms from COSD to NCNG mechanism gradually

  18. Formation of brominated disinfection byproducts from natural organic matter isolates and model compounds in a sulfate radical-based oxidation process

    KAUST Repository

    Wang, Yuru

    2014-12-16

    A sulfate radical-based advanced oxidation process (SR-AOP) has received increasing application interest for the removal of water/wastewater contaminants. However, limited knowledge is available on its side effects. This study investigated the side effects in terms of the production of total organic bromine (TOBr) and brominated disinfection byproducts (Br-DBPs) in the presence of bromide ion and organic matter in water. Sulfate radical was generated by heterogeneous catalytic activation of peroxymonosulfate. Isolated natural organic matter (NOM) fractions as well as low molecular weight (LMW) compounds were used as model organic matter. Considerable amounts of TOBr were produced by SR-AOP, where bromoform (TBM) and dibromoacetic acid (DBAA) were identified as dominant Br-DBPs. In general, SR-AOP favored the formation of DBAA, which is quite distinct from bromination with HOBr/OBr- (more TBM production). SR-AOP experimental results indicate that bromine incorporation is distributed among both hydrophobic and hydrophilic NOM fractions. Studies on model precursors reveal that LMW acids are reactive TBM precursors (citric acid > succinic acid > pyruvic acid > maleic acid). High DBAA formation from citric acid, aspartic acid, and asparagine was observed; meanwhile aspartic acid and asparagine were the major precursors of dibromoacetonitrile and dibromoacetamide, respectively.

  19. Functional Characterization of Salicylic Acid Carboxyl Methyltransferase from Camellia sinensis, Providing the Aroma Compound of Methyl Salicylate during the Withering Process of White Tea.

    Science.gov (United States)

    Deng, Wei-Wei; Wang, Rongxiu; Yang, Tianyuan; Jiang, Li'na; Zhang, Zheng-Zhu

    2017-12-20

    Methyl salicylate (MeSA) is one of the volatile organic compounds (VOCs) that releases floral scent and plays an important role in the sweet flowery aroma of tea. During the withering process for white tea producing, MeSA was generated by salicylic acid carboxyl methyltransferase (SAMT) with salicylic acid (SA), and the specific floral scent was formed. In this study, we first cloned a CsSAMT from tea leaves (GenBank accession no. MG459470) and used Escherichia coli and Saccharomyces cerevisiae to express the recombinant CsSAMT. The enzyme activity in prokaryotic and eukaryotic expression systems was identified, and the protein purification, substrate specificity, pH, and temperature optima were investigated. It was shown that CsSAMT located in the chloroplast, and the gene expression profiles were quite different in tea organs. The obtained results might give a new understanding for tea aroma formation, optimization, and regulation and have great significance for improving the specific quality of white tea.

  20. A Dynamic study of Mantle processes applying In-situ Methods to Compound Xenoliths: implications for small to intermediate scale heterogeneity

    Science.gov (United States)

    Baziotis, Ioannis; Asimow, Paul; Koroneos, Antonios; Ntaflos, Theodoros; Poli, Giampero

    2013-04-01

    The mantle is the major geochemical reservoir of most rock-forming elements in the Earth. Convection and plate-tectonic driven processes act to generate local and regional heterogeneity within the mantle, which in turn through thermal and chemical interactions modulates ongoing geophysical processes; this feedback shapes the dynamics of the deep interior. Consequently, these processes contribute to the evolution of the earth throughout its geological history. Up to now, the heterogeneity of the mantle has been extensively studied in terms of conventional methods using basalt chemistry, bulk rock and mineral major and trace element analysis of isolated xenolith specimens of varying lithology, and massif exposures. The milestone of the present study, part of an ongoing research project, is the application of in-situ analytical methods such as microprobe, LA-ICP-MS and high resolution SEM in order to provide high quality major and trace element analyses as well as elemental distribution of the coexisting phases in the preserved intra-mantle lithologies, Particularly, in the context of the current study we used selected compound xenoliths from San Carlos (Arizona, USA), Kilbourne Hole (New Mexico, USA), Cima Dome and Dish Hill suites (California, USA), San Quintin (Baja California, Mexico) and Chino Valley (Arizona, USA), from the Howard Wilshire collection archived at the Smithsonian Institution. The selection of these compound xenoliths was based upon freshness and integrity of specimens, maximum distance on both sides of lithologic contacts, and rock types thought most likely to represent subsolidus juxtaposition of different lithologies that later partially melted in contact. The San Carlos samples comprise composite xenoliths with websterite, lherzolite and clinopyroxenite layers or clinopyroxenite veins surrounded by lherzolite or orthopyroxenite-rich rims. The Kilbourne Hole suite comprises spinel-(olivine) clinopyroxenite and orthopyroxenite dikes cutting