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Sample records for level microwave irradiation

  1. Low-level microwave irradiation and central cholinergic systems

    SciTech Connect

    Lai, H.; Carino, M.A.; Horita, A.; Guy, A.W. )

    1989-05-01

    Our previous research showed that 45 min of exposure to low-level, pulsed microwaves (2450-MHz, 2-microseconds pulses, 500 pps, whole-body average specific absorption rate 0.6 W/kg) decreased sodium-dependent high-affinity choline uptake in the frontal cortex and hippocampus of the rat. The effects of microwaves on central cholinergic systems were further investigated in this study. Increases in choline uptake activity in the frontal cortex, hippocampus, and hypothalamus were observed after 20 min of acute microwave exposure, and tolerance to the effect of microwaves developed in the hypothalamus, but not in the frontal cortex and hippocampus, of rats subjected to ten daily 20-min exposure sessions. Furthermore, the effects of acute microwave irradiation on central choline uptake could be blocked by pretreating the animals before exposure with the narcotic antagonist naltrexone. In another series of experiments, rats were exposed to microwaves in ten daily sessions of either 20 or 45 min, and muscarinic cholinergic receptors in different regions of the brain were studied by 3H-QNB binding assay. Decreases in concentration of receptors occurred in the frontal cortex and hippocampus of rats subjected to ten 20-min microwave exposure sessions, whereas increase in receptor concentration occurred in the hippocampus of animals exposed to ten 45-min sessions. This study also investigated the effects of microwave exposure on learning in the radial-arm maze. Rats were trained in the maze to obtain food reinforcements immediately after 20 or 45 min of microwave exposure.

  2. Psychoactive-drug response is affected by acute low-level microwave irradiation

    SciTech Connect

    Lai, H.; Horita, A.; Chou, C.K.; Guy, A.W.

    1983-01-01

    The effects of various psychoactive drugs were studied in rats exposed for 45 min in a circularly polarized, pulsed microwave field (2450 MHz; SAR 0.6 W/kg; 2-microseconds pulses, 500 pps). Apomorphine-induced hypothermia and stereotypy were enhanced by irradiation. Amphetamine-induced hyperthermia was attenuated while stereotypy was unaffected. Morphine-induced catalepsy and lethality were enhanced by irradiation at certain dosages of the drug. Since these drugs have different modes of action on central neural mechanisms and the effects of microwaves depend on the particular drug studied, these results show the complex nature of the effect of microwave irradiation on brain functions.

  3. Acute low-level microwave exposure and central cholinergic activity: studies on irradiation parameters

    SciTech Connect

    Lai, H.; Horita, A.; Guy, A.W.

    1988-01-01

    Sodium-dependent high-affinity choline uptake was measured in the striatum, frontal cortex, hippocampus, and hypothalamus of rats after acute exposure (45 min) to pulsed (2 microseconds, 500 pps) or continuous-wave 2,450-MHz microwaves in cylindrical waveguides or miniature anechoic chambers. In all exposure conditions, the average whole-body specific absorption rate was at 0.6 W/kg. Decrease in choline uptake was observed in the frontal cortex after microwave exposure in all of the above irradiation conditions. Regardless of the exposure system used, hippocampal choline uptake was decreased after exposure to pulsed but not continuous-wave microwaves. Striatal choline uptake was decreased after exposure to either pulsed or continuous-wave microwaves in the miniature anechoic chamber. No significant change in hypothalamic choline uptake was observed under any of the exposure conditions studied. We conclude that depending on the parameters of the radiation, microwaves can elicit specific and generalized biological effects.

  4. Low-level microwave irradiation and central cholinergic activity: a dose-response study

    SciTech Connect

    Lai, H.; Carino, M.A.; Horita, A.; Guy, A.W.

    1989-01-01

    Rats were irradiated with circularly polarized, 2,450-MHz pulsed microwaves (2-microseconds pulses, 500 pulses per second (pps)) for 45 min in the cylindrical waveguide system of Guy et al. Immediately after exposure, sodium-dependent high-affinity choline uptake, an indicator of cholinergic activity in neural tissue, was measured in the striatum, frontal cortex, hippocampus, and hypothalamus. The power density was set to give average whole-body specific absorption rates (SAR) of 0.3, 0.45, 0.6, 0.75, 0.9, or 1.2 W/kg to study the dose-response relationship between the rate of microwave energy absorption and cholinergic activity in the different areas of the brain. Decrease in choline uptake was observed in the striatum at a SAR of 0.75 W/kg and above, whereas for the frontal cortex and hippocampus, decreases in choline uptake were observed at a SAR of 0.45 W/kg and above. No significant effect was observed in the hypothalamus at the irradiation power densities studied. The probit analysis was used to determine the SAR50 in each brain area, i.e., the SAR at which 50% of maximum response was elicited. SAR50 values for the striatum, frontal cortex, and hippocampus were 0.65, 0.38, and 0.44 W/kg, respectively.

  5. Effects of low-level microwave irradiation on hippocampal and frontal cortical choline uptake are classically conditionable

    SciTech Connect

    Lai, H.; Horita, A.; Chou, C.K.; Guy, A.W.

    1987-08-01

    In previous research, we found that sodium-dependent high-affinity choline uptake in the hippocampus and frontal cortex of the rat was lowered after acute (45 min) exposure to low-level 2450-MHz pulsed microwaves (power density 1 mW/cm2; average whole body specific absorption rate, 0.6 W/kg; 2 mu sec pulses, 500 pps). In the present experiment, we investigated developments of tolerance and classical conditioning to these effects of microwaves. Rats were exposed to microwaves in cylindrical waveguides in 10 daily sessions (45 min per session). In an 11th session, we subjected the rats to either microwave (study of tolerance) or sham exposure (study of conditioned effect) for 45 min, and immediately measured choline uptake in the hippocampus and frontal cortex. We found that tolerance, a decrease in response to microwaves, developed to the effect of microwaves on choline uptake in the hippocampus, but not in the frontal cortex. Conditioned effects were also observed: an increase in choline uptake in the hippocampus and a decrease in uptake in the frontal cortex. These data suggest that the effects of microwaves on choline uptake in the hippocampus and frontal cortex are classically conditionable, probably to cues in the exposure environment.

  6. Influences of Microwave Irradiation on Environment

    NASA Astrophysics Data System (ADS)

    Murakami, H.; Abe, Y.; Iwata, T.; Kudo, I.; Saito, K.; Okuda, T.

    2004-12-01

    An experimental facility to evaluate the long-duration influence of microwave to environment, a so-called long duration microwave exposure facility (LDMEF), was constructed in Tsukuba in 1994, and so far irradiation tests on plants accumulated over 40,000 hours have been conducted with the aid of 2.45 GHz magnetron. The LDMEF consists of a pair of outdoor electromagnetically isolated areas, one under the influence of microwave irradiation with a 500 W magnetron and one without microwave irradiation. The growth rates of plants in both areas were compared and evaluated with the experimental data for the temperature distribution in the soil and power distribution of microwave. Although any appreciable influence of microwave was not noticed in the power density less than 10 mW/cm2 , the experimental results showed a significant growth rate enhancement when the power density became over 10 mW/cm2 . However, the growth was rather depressed when the power density increased over 15 mW/cm2 . These effects are well explained by the temperature and moisture in the soil which are also under an appreciable influence of microwave irradiation [1,2]. In this context, we newly constructed an indoor irradiation facility, in which the growth conditions of plants under a constant soil temperature can be maintained. In addition, irradiation with a 5.8 GHz magnetron will be conducted in the new facility. In parallel to a series of indoor and outdoor irradiation tests on plants, the influence of microwave irradiation on the growth pattern of albino mouse will be conducted. This experiment will be the first experimental evaluation for the influence of microwave irradiation on animals.

  7. Preparation of Orally Disintegrating Tablets Containing Powdered Tea Leaves with Enriched Levels of Bioactive Compounds by Means of Microwave Irradiation Technique.

    PubMed

    Tanaka, Hironori; Iwao, Yasunori; Izumikawa, Masahiro; Sano, Syusuke; Ishida, Hitoshi; Noguchi, Shuji; Itai, Shigeru

    2016-01-01

    In the present study, a microwave treatment process has been applied to prepare orally disintegrating tablets (ODTs) containing powdered tea leaves with enriched levels of the anti-inflammatory compounds such as chafuroside A (CFA) and chafuroside B (CFB). The use of distilled water as the adsorbed and granulation solvents in this preparation process afforded tablets with a long disintegration time (more than 120 s). The CFA and CFB contents of these tablets did not also change after 4 min of microwave irradiation due to the tablet temperature, which only increased to 100°C. In contrast, the tablet temperature increased up to 140°C after 3 min of microwave irradiation when a 1.68 M Na2HPO4 solution instead of distilled water. Notably, the disintegration time of these tablets was considerably improved (less than 20 s) compared with the microwave-untreated tablets, and there were 7- and 11-fold increases in their CFA and CFB contents. In addition, the operational conditions for the preparation of the tablets were optimized by face-centered composite design based on the following criteria: tablet hardness greater than 13 N, disintegration time less than 30 s and friability less than 0.5%. The requirements translated into X1 (the amount of granulation solvent), X2 (tableting pressure) and X3 (content of the powdered tea leaves) values of 45%, 0.43 kN and 32%, respectively, and the ODTs containing powdered tea leaves prepared under these optimized conditions were found to show excellent tablet properties and contain enriched levels of CFA and CFB. PMID:27581633

  8. Influence of microwave irradiation on enzyme kinetics

    NASA Astrophysics Data System (ADS)

    Pavelkić, V. M.; Stanisavljev, D. R.; Gopčević, K. R.; Beljanski, M. V.

    2009-09-01

    The in vitro effect of 2.45 GHz microwave irradiation on porcine pepsin activity under controlled temperature and absorbed microwave power via kinetic parameters was evaluated. Kinetic study with respect of time of irradiation demonstrated the existence of an inactivation effect of microwaves at pH 2 on pepsin molecule. Bovine serum albumin (BSA)-bromphenol blue (BPB) complex was used as substrate for the assay of pepsin by kinetic method. Depending on absorbed microwave dose, the degree of caused inactivation varies from 39.11 to 45.91% for 5 and 20 min of pepsin MW irradiation, respectively. The V maxapp and K mapp were calculated for low (5 min of MW irradiation) and higher specific absorbed dose (20 min of MW irradiation), as well as for untreated enzyme, from double reciprocal Lineweaver-Burk plot. The effect of microwaves on substrate (BSA-BPB complex) was also investigated. For reaction performed with MW irradiated substrate for 5 min the reaction rate was decreased for 15.15%, while for 20 min of substrate irradiation reaction rate was decreased for 25.52% compared to the control reaction.

  9. Microwave Irradiation on Halloysite-Polypropylene Nanocomposites

    NASA Astrophysics Data System (ADS)

    Espino, Omar; Yust, Brian; Chipara, Dorina; Ajayan, Pullickel; Chipara, Alin; Chipara, Mircea; Utrgv Collaboration; Rice Collaboration

    Halloysite is an unique cyllindrical nanoclay characterized by poor electrical and thermal conductivity, which may become the filler of choice for the reinforcement of polymeric matrix, where electrical or thermal insulation are required. The main limits in the use of halloysite as replacement for carbon nanotube (CNT) are: 1. Smaller aspect ratio as halloysites are typically shorter than CNTs. 2. Smaller Young modulus of halloysites compared with CNTs. 3. Reduced thermal stability due to the loss of water upon heating. A research on halloysite dispersed within isotactic polypropylene is reported. To improve the interface between the halloysite and the polymeric matrix a microwave irradiation step has been considered. The local heating of the halloysite nanotubes is mediated by the absorbed/structural water content of the nanoclay. Nanocomposites loaded by various amounts of halloysite ranging from 0 % to 20 % wt. have been prepared by melt mixing by using a Haake RheoMixer. The as obtained nanocomposites have been subjected to microwave irradiation at 75 W in an Anton Paar Monowave 300 system and various irradiation times ranging from 5, 10, 15, 30, 45, and 60 minutes. The effect of microwave irradiation has been studied by Raman and FTIR spectroscopy

  10. EXPEDITIOUS SYNTHESIS OF IONIC LIQUIDS USING ULTRASOUND AND MICROWAVE IRRADIATION

    EPA Science Inventory

    Environmentally friendlier preparations of ionic liquids have been developed that proceed expeditiously under the influence of microwave or ultrasound irradiation conditions using neat reactants, alkylimidazoles and alkyl halides. A number of useful ionic liquids have been prepar...

  11. MICROWAVE IRRADIATION FOR RAPID KILLING AND FIXING OF PLANT TISSUE

    EPA Science Inventory

    Irradiation by microwaves allow for rapid billing and fixing of plant tissue, with excellent cellular integrity for histological examination. One or two exposures to microwaves for three seconds in formalin/acetic acid/alcohol gave good preservation of nuclei, chloroplasts and ot...

  12. EXPEDITIOUS SOLVENT-FREE ORGANIC SYNTHESES USING MICROWAVE IRRADIATION

    EPA Science Inventory

    Microwave-expedited solvent-free synthetic processes involve the exposure of neat reactants to microwave (MW) irradiation in the presence of supported reagents or catalysts on mineral oxides. Recent developments are described and the salient features of these high yield protocol...

  13. Bioethanol production from Ficus religiosa leaves using microwave irradiation.

    PubMed

    Klein, Miri; Griess, Ofir; Pulidindi, Indra Neel; Perkas, Nina; Gedanken, Aharon

    2016-07-15

    A microwave assisted feasible process for the production of bioethanol from Ficus religiosa leaves was developed. Under the process conditions (8 min. microwave irradiation, 1 M HCl), 10.1 wt% glucose yield was obtained from the leaves. Microwave based hydrolysis process yielded higher glucose content (10.1 wt%) compared to the conventional hydrothermal process (4.1 wt%). Upon fermentation of the hydrolysate using Baker's yeast, 3 wt% (dry wt. basis) of bioethanol was produced. PMID:27064733

  14. Orthodontic instrument sterilization with microwave irradiation

    PubMed Central

    Yezdani, Arif; Mahalakshmi, Krishnan; Padmavathy, Kesavaram

    2015-01-01

    Objective: This study was designed to evaluate the efficiency of microwave sterilization of orthodontic instruments and molar bands immersed in plain distilled water with and without oral rinse, and to ascertain the minimum time of exposure required to sterilize. Materials and Methods: The orthodontic instruments (hinged and nonhinged), molar bands and mouth mirrorsused in the patient 's mouth were selected for the study. The instruments were divided into two groups – Group I with oral rinse-set A (0.01% chlorhexidine gluconate) and set B (0.025% betadine) and Group II (included sets C and D without oral rinse). The instruments of set A, B and C were microwaved at 2,450 MHz, 800 W for 5 min, whereas, set D was microwaved for 10 min at the same above mentioned specifications. The efficacy of sterilization was assessed by stab inoculation of the instruments onto trypticase soya agar plates. The plates were checked for bacterial growth following incubation at 37 °C for 24 h. For sterility control,Geobacillus stearothermophilus (MTCC 1518) was included. Results: No growth was observed in the plates that were inoculated with the microwaved orthodontic instruments of sets A, B and D, whereas scanty bacterial growth was observed in the plates inoculatedwith the microwaved set C instruments. Conclusion: Effective sterilization was achieved when the orthodontic instruments and molar bands were immersed in distilled water without oral rinse and microwaved for 10 min as also for those that were immersed in distilled water with oral rinse and microwaved for 5 min. PMID:26015686

  15. GREENER CHEMICAL SYNTHESES USING MICROWAVE IRRADIATION

    EPA Science Inventory

    Greener solvent-free protocols involve microwave (MW) exposure of neat reactants catalyzed by the surfaces of recyclable mineral supports such as alumina, silica and clay which are applicable to a wide range of cleavage, condensation, cyclization, oxidation and reduction reaction...

  16. 'GREENER' CHEMICAL SYNTHESIS USING MICROWAVE IRRADIATION

    EPA Science Inventory

    A solvent-free approach that involves microwave (MW) exposure of neat reactants (undiluted) catalyzed by the surfaces of recyclable mineral supports such as alumina, silica, clay, or 'doped' surfaces is presented which is applicable to a wide range of cleavage, condensation, cycl...

  17. 'GREENER' SOLVENT-FREE CHEMICAL SYNTHESIS USING MICROWAVE IRRADIATION

    EPA Science Inventory

    Solvent-free approach that involves microwave (MW) irradiation of neat reactants (undiluted) catalyzed by the surfaces of less-expensive and recyclable mineral supports such as alumina, silica, clay, or 'doped' surfaces is presented which is applicable to a wide range of cleavage...

  18. Microwave Irradiation on Graphene Dispersed Within Polymeric Matrices

    NASA Astrophysics Data System (ADS)

    Cisneros, Jorge; Yust, Brian; Chipara, Mircea

    Graphene is a two dimensional nanomaterial with high thermal and electric conductivity and Young modulus. These features make graphene an ideal reinforcement for polymeric matrices. However, the mechanical features of polymer-carbon nanostructured composites are limited by the dispersion of the filler and by the delamination or microcracks initiated at the interface between the polymeric matrix and nanofiller. This last weakness can be addressed by improving the interface via chemical and physical methods. Microwave heating of graphite is a very efficient approach if the polymeric matrix does not also have a strong absorption. During the irradiation, the nanofiller is preferentially heated; the local melting of the polymer at the interface improves the interface by filling the microcracks and delaminations. Nanocomposites of polystyrene-poly(ethylene-ran-butylene)-polystyrene loaded by various amounts of graphene ranging from 0 % to 20 % wt. have been prepared by solution mixing using chloroform as solvent. The as obtained nanocomposites have been subjected to microwave irradiation in an Anton Paar Monowave 300 system operating at 75 W, for various irradiation times 5, 10, 15, 30, 45, and 60 minutes. The effect of microwave irradiation has been studied by Raman spectroscopy.

  19. Study on dehydrochlorination of waste poly (vinyl chloride) resins by microwave irradiation

    NASA Astrophysics Data System (ADS)

    Moriwaki, Saburo; Qian, Qingrong; Sunohara, Satoshi; Machida, Motoi; Tatsumoto, Hideki

    Waste poly (vinyl chloride: PVC) resins are experimentally dehydrochlorinated by microwave irradiation. The following unique results are obtained: (1) plasticizer in PVC resin absorbs microwave power more effectively than PVC polymer. The higher the plasticizer content in PVC resin, the higher is the dehydrochlorination reaction (2) low PVC polymer content materials such as cushion floor require high microwave irradiation power to secure a high dehydrochlorination yield, (3) calcium carbonate in PVC resin reacts with released hydrochloric acid gas and results calcium chloride during microwave irradiation, (4) additives in PVC resin strongly influence dehydrochlorination yield, (5) it is evidenced that the PVC copolymer is also dehydrochlorinated by microwave irradiation.

  20. Fast Transmethylation of Serum Lipids using Microwave Irradiation

    PubMed Central

    Lin, Yu Hong; Loewke, James D.; Hyun, Duk Y.; Leazer, Jay; Hibbeln, Joseph R.

    2012-01-01

    Microwave irradiation as the energy source for one–step direct transesterification of fatty acids in human serum lipids was examined in solvent system of methanol: hexane: acetyl chloride based on Lepage & Roy assay. Innovative and explosion proof single–mode or multimode microwave accelerate reaction system was employed. Recoveries were calculated as the percentage of fatty acid concentrations measured by microwave assay to those by reference method Lepage & Roy assay that utilized conductive heating at 100 °C for 60 min. At conditions of 100 °C for 1 min in Single–mode (S4–100×1), or 125 °C for 5 min in Multimode (M5–125×5), the recoveries were 100–103% for the total fatty acids and 96–106% for each categorized fatty acid, including saturates, monounsaturates, n-6 PUFA, and n-3 PUFA. For individual PUFA, the mean recoveries were 102–105% for 18:2n-6 and 18:3n-3; 99, 109, and 95% for 20:4n-6, 20:5n-3, and 22:6n-3, respectively. Thus, fatty acid concentrations determined by microwave fatty acid assay were accurate to those results by the reference method, when the microwave conditions were optimal. In summary, the microwave irradiation could replace conductive heating in one–step direct transesterification, and reduce duration from 60 min to 5 min or less. This methodology may be applied in both the absolute and relative quantification of serum total fatty acids. PMID:23015312

  1. Synthesis of nanosize BPO{sub 4} under microwave irradiation

    SciTech Connect

    Wang, Rui; Jiang, Heng; Gong, Hong; Zhang, Jun

    2012-08-15

    Highlights: ► Nanosize BPO{sub 4} are prepared under microwave-irradiation conditions. ► This reaction is only performed at less than 640 W power for 2.5–5 min. ► The particles of sample irradiated at 400 W are 40–90 nm in size and well dispersed. ► A simple, fast and green procedure for synthesis of nanosize BPO{sub 4} is developed. -- Abstract: Nanosize BPO{sub 4} was synthesized using H{sub 3}BO{sub 3} and H{sub 3}PO{sub 4} (85%) as raw materials under microwave irradiation. This reaction was performed at powers lower than 640 W and irradiation time ranging from 2.5 min to 5 min, which were only a fraction of the time required for conventional synthetic procedures. The structure of the as-prepared BPO{sub 4} is analogous to that of a high cristobalite. The particle sizes of the samples irradiated at 640 and 400 W range from 40 nm to 90 nm and 30 nm to 60 nm, respectively. The effects of different conditions on the experimental outcome are also discussed.

  2. ADVANCES IN GREEN CHEMISTRY: CHEMICAL SYNTHESES USING MICROWAVE IRRADIATION, ISBN 81-901238-5-8

    EPA Science Inventory

    16. Abstract Advances in Green Chemistry: Chemical Syntheses Using Microwave Irradiation
    Microwave-accelerated chemical syntheses in solvents as well as under solvent-free conditions have witnessed an explosive growth. The technique has found widespread application predomi...

  3. Vaccine Biotechnology by Accelerated Electron Beam and Microwave Irradiation

    NASA Astrophysics Data System (ADS)

    Craciun, Gabriela D.; Togoe, Iulian I.; Tudor, Laurentiu M.; Martin, Diana I.; Manaila, Elena N.; Ighigeanu, Daniel I.; Iacob, Nicusor I.; Oproiu, Constantin V.

    2007-04-01

    A new biotechnology for obtaining a commercial vaccine that contains either Fusobacterium necrophorum (F.n.) exotoxins inactivated by accelerated electron beam (EB) and microwave (MW) irradiation, or exotoxins isolated from F.n. cultures irradiated with EB+MW, is presented. This vaccine is designed for prophylaxis of ruminant infectious pododermatitis (IP) produced by F.n. Also, the research results concerning the effects of combined chemical adjuvant and EB+MW irradiation on F.n. immune capacity are discussed. The vaccine's efficacy will be tested in ruminant farms in which IP evolves. It is expected that this new vaccine to offer a better protection, more than 60%, which is the best presently obtained result in ruminant farms.

  4. Microwave Irradiation of Nanohydroxyapatite from Chicken Eggshells and Duck Eggshells

    PubMed Central

    Sajahan, Nor Adzliana; Wan Ibrahim, Wan Mohd Azhar

    2014-01-01

    Due to similarity in composition to the mineral component of bones and human hard tissues, hydroxyapatite with chemical formula Ca10(PO4)6(OH)2 has been widely used in medical field. Both chicken and duck eggshells are mainly composed of calcium carbonate. An attempt has been made to fabricate nanohydroxyapatite (nHA) by chicken (CES) and duck eggshells (DES) as calcium carbonate source (CaCO3). CES and DES were reacted with diammonium hydrogen [(NH4)2HPO4] solution and subjected to microwave heating at 15 mins. Under the effect of microwave irradiation, nHA was produced directly in the solution and involved in crystallographic transformation. Sample characterization was done using by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). PMID:25383364

  5. Effect of microwave irradiation on selective heating behavior and magnetic separation characteristics of Panzhihua ilmenite

    NASA Astrophysics Data System (ADS)

    Zhao, Wei; Chen, Jin; Chang, Xiaodong; Guo, Shenghui; Srinivasakannan, C.; Chen, Guo; Peng, Jinhui

    2014-05-01

    The influences of microwave irradiation on the surface characteristics of Panzhihua ilmenite were systematically investigated. The crystal structures, surface morphology and surface chemical functional groups of ilmenite were characterized before and after microwave irradiation and magnetic separation for different microwave treatment times by using various methods, such as XRD, SEM, and FT-IR, respectively. XRD analysis showed that the microwave treated ilmenite has the strongest peaks of phase more than that of raw samples, indicates that the crystalline compound of ilmenite increased with the microwave irradiation time. SEM analysis showed the micro-cracking appeared at many grain boundaries of ilmenite after being pretreated by microwave treatment. The separations of ilmenite from gangue minerals were completed and the micro-fissure within ilmenite minerals were also formed, which could be attributed to the microwave selective heating characteristics of the different minerals and compounds, and the thermal stresses were caused by the uniform heat rate disturbed under microwave irradiation. The mineral processing results showed that the magnetic separation characteristics and properties of microwave treated ilmenite samples were better than that of microwave untreated ilmenite samples. It was concluded that microwave irradiation can be applied effectively and efficiently to the irradiation processes of Panzhihua ilmenite.

  6. Controlled synthesis of novel octapod platinum nanocrystals under microwave irradiation

    SciTech Connect

    Dai, Lei; Chi, Quan; Zhao, Yanxi; Liu, Hanfan; Zhou, Zhongqiang; Li, Jinlin; Huang, Tao

    2014-01-01

    Graphical abstract: Under microwave irradiation, novel octapod Pt nanocrystals were synthesized by reducing H{sub 2}PtCl{sub 6} in TEG with PVP as a stabilizer. The as-prepared Pt nanocrystals displayed a unique octapod nanostructure with five little mastoids in each concave center. The use of KI was crucial to the formation of novel Pt octapods. Novel Octapod Platinum Nanocrystals. - Highlights: • A novel octapod Pt nanocrystals different from the common octapod were obtained. • The use of KI was crucial to the formation of the novel Pt octapods. • Microwave was readily employed in controlled synthesis of the novel Pt octapods. - Abstract: Microwave was employed in the shape-controlled synthesis of Pt nanoparticles. Novel octapod Pt nanocrystals enclosed with (1 1 1) facets were readily synthesized with H{sub 2}PtCl{sub 6} as a precursor, tetraethylene glycol (TEG) as both a solvent and a reducing agent, polyvinylpyrrolidone (PVP) as a stabilizer in the presence of an appropriate amount of KI under microwave irradiation for 140 s. The as-prepared Pt nanocrystals displayed a unique octapod nanostructure with five little mastoids in each concave center and exhibited higher electrocatalytic activity than commercial Pt black in the electro-oxidations of methanol and formic acid. The results demonstrated that the use of KI was crucial to the formation of Pt octapods. KI determined the formation of the novel octapod Pt nanocrystals by tuning up the reduction kinetics and adsorbing on the surfaces of growing Pt nanoparticles. The optimum molar ratio of H{sub 2}PtCl{sub 6}/KI/PVP was 1/30/45.

  7. An evaluation of the effect of microwave irradiation on bone decalcification aimed to DNA extraction.

    PubMed

    Imaizumi, Kazuhiko; Taniguchi, Kei; Ogawa, Yoshinori

    2013-09-01

    An effect of intermittent microwave irradiation on decalcification of compact bone followed by DNA extraction was verified. In order to perform quantitative analysis regarding the degree of decalcification, Cubic bone specimens were prepared from bovine metacarpal bone and micro-focus X-ray CT imaging was applied to measure precise volume of decalcified area in the cubes. Microwave irradiation was performed under strict control of temperature using commercially available experimental device which is designed for advancing tissue fixation, decalcification, and antigen-antibody reaction by intermittent microwave. The integrity of the DNA obtained from irradiated specimen was also examined by PCR analysis. The results of morphological analysis with CT imaging showed that microwave irradiation has a positive effect on decalcification though that effect is not so drastic. The results obtained from PCR analysis showed that microwave irradiation decrease amplifiable DNA, suggesting that we should be careful to use microwave for the purpose of bone DNA extraction. PMID:23838266

  8. Microwave irradiation biodiesel processing of waste cooking oil

    NASA Astrophysics Data System (ADS)

    Motasemi, Farough; Ani, Farid Nasir

    2012-06-01

    Major part of the world's total energy output is generated from fossil fuels, consequently its consumption has been continuously increased which accelerates the depletion of fossil fuel reserves and also increases the price of these valuable limited resources. Biodiesel is a renewable, non-toxic and biodegradable diesel fuel which it can be the best environmentally friendly and easily attainable alternative for fossil fuels. The costs of feedstock and production process are two important factors which are particularly against large-scale biodiesel production. This study is intended to optimize three critical reaction parameters including intensity of mixing, microwave exit power and reaction time from the transesterification of waste cooking oil by using microwave irradiation in an attempt to reduce the production cost of biodiesel. To arrest the reaction, similar quantities of methanol/oil molar ratio (6:1) and potassium hydroxide (2% wt) as the catalyst were used. The results showed that the best yield percentage (95%) was obtained using 300W microwave exit power, 300 rpm stirrer speed (intensity of mixing) and 78°C for 5 min. It was observed that increasing the intensity of mixing greatly ameliorates the yield percentage of biodiesel (up to 17%). Moreover, the results demonstrate that increasing the reaction time in the low microwave exit power (100W) improves the yield percentage of biodiesel, while it has a negative effect on the conversion yield in the higher microwave exit power (300W). From the obtained results it was clear that FAME was within the standards of biodiesel fuel.

  9. Changes in thermoregulatory behavior during microwave irradiation

    SciTech Connect

    Adair, E.R.

    1981-10-01

    Voluntary behavioral action is an organism's first defense against exogenous thermal challenge. Endotherms and ectotherms alike use behavioral strategies whenever possible to counteract inhospitable alterations in the exchange of thermal energy between their bodies and the environment. Responses as diverse as the thermotropisms of unicellular organisms and the complex behavior-plus-technology of man's lunar walk share a common purpose--that of providing a hospitable microclimate so that the internal body temperature may be regulated with precision at a characteristic (neutral) level. For ectothermic species, these behaviors represent most of the thermoregulatory response available to the organism. For endothermic species, these behaviors represent most of the thermoregulatory response available to the organism. For endothermic species, these behaviors ensure minimal involvement of innate mechanisms of heat production and heat loss during thermoregulation, thus conserving the body's energy stores and water.

  10. Gold Nanoparticles and Microwave Irradiation Inhibit Beta-Amyloid Amyloidogenesis

    NASA Astrophysics Data System (ADS)

    Araya, Eyleen; Olmedo, Ivonne; Bastus, Neus G.; Guerrero, Simón; Puntes, Víctor F.; Giralt, Ernest; Kogan, Marcelo J.

    2008-11-01

    Peptide-Gold nanoparticles selectively attached to β-amyloid protein (Aβ) amyloidogenic aggregates were irradiated with microwave. This treatment produces dramatic effects on the Aβ aggregates, inhibiting both the amyloidogenesis and the restoration of the amyloidogenic potential. This novel approach offers a new strategy to inhibit, locally and remotely, the amyloidogenic process, which could have application in Alzheimer’s disease therapy. We have studied the irradiation effect on the amyloidogenic process in the presence of conjugates peptide-nanoparticle by transmission electronic microscopy observations and by Thioflavine T assays to quantify the amount of fibrils in suspension. The amyloidogenic aggregates rather than the amyloid fibrils seem to be better targets for the treatment of the disease. Our results could contribute to the development of a new therapeutic strategy to inhibit the amyloidogenic process in Alzheimer’s disease.

  11. [Characteristics of high solid content sludge with microwave irradiation].

    PubMed

    Qiao, Wei; Wang, Wei; Xun, Rui; Zhou, Gang; Wan, Xiao; Xia, Zhou

    2008-06-01

    This paper focus on changes of high solid content sludge (7%, 9% and 13%) hydrolysis with microwave irradiation also anaerobic biodegradation of treated sludge was tested by biochemical methane potential (BMP) procedure. Results showed that microwave irradiation provided a rapid temperature increasing. Hydrolysis accelerated the solubilization of volatile suspended solid (VSS) and suspended solid (SS). COD, TOC, NH4+-N, TN, and TP concentration of liquor sludge increased, while pH decreased. Sludge solid content was found to be the most influential parameter. VSS and SS dissolving ratio of sludge with 13% solid content were lower than sludge with 7% and 9% solid content. 23% of VSS and 18% of SS dissolved for 9% sludge at 170 degrees C with 5 min, SCOD of liquor was 41 g/L, and concentration of TOC and NH4+-N were 30 g/L and 1 g/L respectively. Biodegradation of treated sludge improved. Methane production of 9% sludge at 170 degrees C with 5 min and 10 min were 27% and 30.8% higher than that of untreated sludge. Hydrolysis time increasing from 5 min to 10 min brought an improvement of 4%, 3.6% and 5.7% methane production at 120 degrees C, 150 degrees C and 170 degrees C. PMID:18763510

  12. Comparison of chromatographic band profiles obtained under microwave irradiated and non-irradiated reversed-phase liquid chromatography column

    SciTech Connect

    Galinada, Wilmer; Guiochon, Georges A

    2005-08-01

    The possible influence of the application of microwave energy to a reversed-phase liquid chromatography column on the mass transfer kinetics and the thermodynamics of equilibrium between mobile and stationary phases was examined. Chromatograms of propylbenzene and phenol were recorded under the same experimental conditions, on the same column, successively irradiated and not. The effect of microwave irradiation on the mass transfer kinetics was determined by measuring the second moment of small pulses of propylbenzene in a 70:30 (v/v) solution of methanol in water and microwave outputs of 15 and 30 W. The effect of microwave irradiation on the equilibrium thermodynamics was determined by measuring the elution time of breakthrough curves of phenol at high concentrations in a 20:80 (v/v) solution of methanol and water and microwave outputs of 15, 50, and 150 W. A qualitative comparison of the profiles of the propylbenzene peaks obtained with and without irradiation suggests that this irradiation affects significantly the peak shapes. However, a qualitative comparison of the profiles of the breakthrough curves of phenol obtained with and without irradiation suggests that this irradiation has no significant effect on their shapes. The peak sharpening observed may be due to an increase in the diffusivity, resulting from the dielectric polarization under microwave irradiation. This effect is directly related to an increase of the rate of mass transfers in the column. In contrast, the similarity of the overloaded band profiles at high concentrations suggests that the equilibrium thermodynamics is unaffected by microwave irradiation. This may be explained by the transparence of the stationary phase to microwaves at 2.45 GHz. The column temperature was measured at the column outlet under irradiation powers of 15, 30, 50, and 150 W. It increases with increasing power, the corresponding effluent temperatures being 25 {+-} 1, 30 {+-} 1, 35 {+-} 1, and 45 {+-} 1 C, respectively.

  13. Synergistic Effects of Combined Electron Beam and Microwave Irradiation on Microorganisms Inactivation

    NASA Astrophysics Data System (ADS)

    Craciun, Gabriela D.; Martin, Diana I.; Manaila, Elena N.; Togoe, Iulian I.; Ighigeanu, Daniel I.; Iacob, Nicusor I.; Ighigeanu, Adelina I.; Oproiu, Constantin V.

    2007-04-01

    Comparative results obtained by using separate and combined electron beam (EB) and microwave (MW) on microorganisms inactivation in natural products such as minced beef, wheat bran, wheat flour and sewage sludge are presented. The combination of advantages of both, EB and MW, in microbiological decontamination process, i.e. the EB high efficiency and MW high selectivity and volumetric heating assures higher material microbiological safety, extends the kind range of microorganisms to be inactivated, reduces the absorbed dose level and irradiation time, and decreases the process costs.

  14. Pyrolysis of Municipal Solid Waste for Syngas Production by Microwave Irradiation

    SciTech Connect

    Gedam, Vidyadhar V.; Regupathi, Iyyaswami

    2012-03-15

    In the present study, we discuss the application of microwave-irradiated pyrolysis of municipal solid waste (MSW) for total recovery of useful gases and energy. The MSW pyrolysis under microwave irradiation highly depends on the process parameters, like microwave power, microwave absorbers, and time of irradiation. The thoroughness of pyrolysis and product recovery were studied by changing the abovesaid variables. Pyrolysis of MSW occurs in the power rating range of 450-850 W-outside this power rating range, pyrolysis is not possible. Experiments were carried out using various microwave absorbers (i.e., graphite, charcoal, and iron) to enhance the pyrolysis even at lower power rating. The results show that the pyrolysis of MSW was possible even at low power ratings. The major composition of the pyrolysis gaseous product were analyzed with GC-MS which includes CO{sub 2}, CO, CH{sub 4}, etc.

  15. Speedy fabrication of diameter-controlled Ag nanowires using glycerolunder microwave irradiation conditions

    EPA Science Inventory

    Diameter-controlled Ag nanowires were rapidly fabricated (1 min) using inexpensive, abundant, and environmentally-friendly glycerol as both reductant and solvent under non-stirred microwave irradiation conditions; no Ag particles were formed using conventional heating methods. Th...

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

    EPA Science Inventory

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

  17. GREENER AND CONTROLLED SYNTHESIS OF NOBLE NANOSTRUCTURES IN AQUEOUS MEDIA USING MICROWAVE IRRADIATION

    EPA Science Inventory

    Microwave-assisted spontaneous reduction of gold salts is described using sugar solutions such as alpha-D-glucose, sucrose and maltose, etc. The expeditious reactions are conducted in aqueous media using microwave irradiation wherein the reduction occurs within 30 to 60 seconds ...

  18. SOLVENT-FREE APPROACH TO EXPEDITIOUS ORGANIC SYNTHESES USING MICROWAVE IRRADIATION

    EPA Science Inventory

    Microwave irradiation has been used for a variety of organic transformations wherein chemical reactions are accelerated because of selective adsorption of microwave (MW) energy by polar molecules, non-polar molecules being inert to the MW dielectric loss. The application of MW ir...

  19. ENVIRONMENTALLY BENIGN ORGANIC TRANSFORMATIONS USING MICROWAVE IRRADIATION UNDER SOLVENT-FREE CONDITIONS

    EPA Science Inventory

    Microwave-expedited solvent-free synthetic processes involve the exposure of neat reactants to microwave (MW) irradiation in the presence of supported reagents or catalysts on mineral oxides. Recent developments are described and the salient features of these high yield protocols...

  20. Microwave radiation, in the absence of hyperthermia, has no detectable effect on synapsin I levels or phosphorylation

    SciTech Connect

    Browning, M.D.; Haycock, J.W.

    1988-09-01

    Recent reports have indicated that microwave radiation can produce effects on a variety of cell types in vitro. To determine whether microwave radiation might be neurotoxic, the effects of microwave radiation on synapsin I have been examined. Synapsin I is a neuron-specific phosphoprotein that is present in all neurons, where it is localized to the presynaptic terminal and is associated with synaptic vesicles. O'Callaghan and Miller have demonstrated that studies of such neuron-specific proteins can provide reliable indices of neurotoxicity. We have used a radioimmunoassay for synapsin I to determine whether microwave irradiation has any effect on the levels of synapsin I. Neither acute nor chronic exposure to microwave irradiation had any detectable effect on synapsin I levels. We have also examined the calcium-dependent phosphorylation of synapsin I in synaptosomes isolated from rats that had been subjected to microwave radiation. The phosphorylation of synapsin I in synaptosomes reflects numerous components of the presynaptic aspect of neuronal transmission. At intensities below that required to produce mild hyperthermia, no effects of microwave irradiation were seen on synapsin I phosphorylation.

  1. A 3D Level Set Method for Microwave Breast Imaging

    PubMed Central

    Colgan, Timothy J.; Hagness, Susan C.; Van Veen, Barry D.

    2015-01-01

    Objective Conventional inverse-scattering algorithms for microwave breast imaging result in moderate resolution images with blurred boundaries between tissues. Recent 2D numerical microwave imaging studies demonstrate that the use of a level set method preserves dielectric boundaries, resulting in a more accurate, higher resolution reconstruction of the dielectric properties distribution. Previously proposed level set algorithms are computationally expensive and thus impractical in 3D. In this paper we present a computationally tractable 3D microwave imaging algorithm based on level sets. Methods We reduce the computational cost of the level set method using a Jacobian matrix, rather than an adjoint method, to calculate Frechet derivatives. We demonstrate the feasibility of 3D imaging using simulated array measurements from 3D numerical breast phantoms. We evaluate performance by comparing full 3D reconstructions to those from a conventional microwave imaging technique. We also quantitatively assess the efficacy of our algorithm in evaluating breast density. Results Our reconstructions of 3D numerical breast phantoms improve upon those of a conventional microwave imaging technique. The density estimates from our level set algorithm are more accurate than those of conventional microwave imaging, and the accuracy is greater than that reported for mammographic density estimation. Conclusion Our level set method leads to a feasible level of computational complexity for full 3D imaging, and reconstructs the heterogeneous dielectric properties distribution of the breast more accurately than conventional microwave imaging methods. Significance 3D microwave breast imaging using a level set method is a promising low-cost, non-ionizing alternative to current breast imaging techniques. PMID:26011863

  2. Evaluation of direct transesterification of microalgae using microwave irradiation.

    PubMed

    Teo, Chee Loong; Idris, Ani

    2014-12-01

    Nannochloropsis sp. wet biomass was directly transesterified under microwave (MW) irradiation in the presence of methanol and various alkali and acid catalyst. Two different types of direct transesterification (DT) were used; one step and two step transesterification. The biodiesel yield obtained from the MWDT was compared with that obtained using conventional method (lipid extraction followed by transesterification) and water bath heating DT method. Findings revealed that MWDT efficiencies were higher compared to water bath heating DT by at least 14.34% and can achieve a maximum of 43.37% with proper selection of catalysts. The use of combined catalyst (NaOH and H2SO4) increased the yield obtained by 2.3-folds (water bath heating DT) and 2.87-folds (MWDT) compared with the one step single alkaline catalyst respectively. The property of biodiesel produced by MWDT has high lubricating property, good cetane number and short carbon chain FAME's compared with water bath heating DT. PMID:25463809

  3. Preparation of ultrafiltration membrane by phase separation coupled with microwave irradiation

    NASA Astrophysics Data System (ADS)

    Suryani, Puput Eka; Purnama, Herry; Susanto, Heru

    2015-12-01

    Preparation of low fouling ultrafiltration membrane is still a big challenge in the membrane field. In this paper, polyether sulfone (PES) ultrafiltration membranes were prepared by non-solvent-induced phase separation (NIPS) coupled with microwave irradiation. Polyethylene glycol (PEG) and polyethylene glycol methacrylate (PEGMA) were used as additives to improve membrane hydrophilicity. In this study, the concentration of additive, irradiation time and microwave power was varied. The membranes were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy, while the performances were tested by adsorptive and ultrafiltration fouling experiments. The results show that the irradiation time and irradiation power are very important parameter that influence the membrane characteristic. In addition, type and concentration of additive are other important parameters. The results suggest that microwave irradiation is the most important parameter influencing the membrane characteristic. Both pure water flux and fouling resistance increase with increasing irradiation time, power irradiation, and additive concentration. PES membrane with addition of 10% w/w PEG and irradiated by 130 W microwave power for 180 seconds is the best membrane performance.

  4. Preparation of ultrafiltration membrane by phase separation coupled with microwave irradiation

    SciTech Connect

    Suryani, Puput Eka; Purnama, Herry; Susanto, Heru

    2015-12-29

    Preparation of low fouling ultrafiltration membrane is still a big challenge in the membrane field. In this paper, polyether sulfone (PES) ultrafiltration membranes were prepared by non-solvent-induced phase separation (NIPS) coupled with microwave irradiation. Polyethylene glycol (PEG) and polyethylene glycol methacrylate (PEGMA) were used as additives to improve membrane hydrophilicity. In this study, the concentration of additive, irradiation time and microwave power was varied. The membranes were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy, while the performances were tested by adsorptive and ultrafiltration fouling experiments. The results show that the irradiation time and irradiation power are very important parameter that influence the membrane characteristic. In addition, type and concentration of additive are other important parameters. The results suggest that microwave irradiation is the most important parameter influencing the membrane characteristic. Both pure water flux and fouling resistance increase with increasing irradiation time, power irradiation, and additive concentration. PES membrane with addition of 10% w/w PEG and irradiated by 130 W microwave power for 180 seconds is the best membrane performance.

  5. Application of Microwave Irradiation and Heat to Improve Gliadin Detection and Ricin ELISA Throughput with Food Samples

    PubMed Central

    Garber, Eric A. E.; Thole, Joseph

    2015-01-01

    The utility of microwave irradiation to accelerate the onset of equilibrium and improve ELISA performance was examined using ELISAs for the detection of the plant toxin ricin and gliadin. The ricin ELISA normally requires several one hour incubations at 37 °C, a total assay time of approximately five hours, and employs a complex buffer containing PBS, Tween-20®, and non-fat milk. Different energy levels and pulse designs were compared to the use of abbreviated incubation times at 37 °C for the detection of ricin in food. The use of microwave irradiation had no significant advantage over the application of heat using an oven incubator and performed worse with some foods. In contrast, a gliadin ELISA that relied on 30 min incubation steps at room temperature and a salt-based buffer performed better upon irradiation but also displayed improvement upon incubating the microtiter plate at 37 °C. Whether microwave irradiation was advantageous compared to incubation in an oven was inconclusive. However, by abbreviating the incubation time of the ricin ELISA, it was possible to cut the assay time to less than 2 hours and still display LOD values < 10 ppb and recoveries of 78%–98%. PMID:26110503

  6. Application of Microwave Irradiation and Heat to Improve Gliadin Detection and Ricin ELISA Throughput with Food Samples.

    PubMed

    Garber, Eric A E; Thole, Joseph

    2015-06-01

    The utility of microwave irradiation to accelerate the onset of equilibrium and improve ELISA performance was examined using ELISAs for the detection of the plant toxin ricin and gliadin. The ricin ELISA normally requires several one hour incubations at 37 °C, a total assay time of approximately five hours, and employs a complex buffer containing PBS, Tween-20®, and non-fat milk. Different energy levels and pulse designs were compared to the use of abbreviated incubation times at 37 °C for the detection of ricin in food. The use of microwave irradiation had no significant advantage over the application of heat using an oven incubator and performed worse with some foods. In contrast, a gliadin ELISA that relied on 30 min incubation steps at room temperature and a salt-based buffer performed better upon irradiation but also displayed improvement upon incubating the microtiter plate at 37 °C. Whether microwave irradiation was advantageous compared to incubation in an oven was inconclusive. However, by abbreviating the incubation time of the ricin ELISA, it was possible to cut the assay time to less than 2 hours and still display LOD values < 10 ppb and recoveries of 78%-98%. PMID:26110503

  7. GREENER SYNTHESIS OF HETEROCYCLIC COMPOUNDS USING MICROWAVE IRRADIATION

    EPA Science Inventory

    An introduction of our interest in the microwave-assisted greener synthesis of a variety of heterocyclic compounds will be presented. It involves microwave (MW) exposure of neat reactants (undiluted) catalyzed by the surfaces of recyclable mineral supports, such as alumina, sili...

  8. Mechanism for microwave heating of 1-(4‧-cyanophenyl)-4-propylcyclohexane characterized by in situ microwave irradiation NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Tasei, Yugo; Yamakami, Takuya; Kawamura, Izuru; Fujito, Teruaki; Ushida, Kiminori; Sato, Motoyasu; Naito, Akira

    2015-05-01

    Microwave heating is widely used to accelerate organic reactions and enhance the activity of enzymes. However, the detailed molecular mechanism for the effect of microwave on chemical reactions is not yet fully understood. To investigate the effects of microwave heating on organic compounds, we have developed an in situ microwave irradiation NMR spectroscopy. 1H NMR spectra of 1-(4‧-cyanophenyl)-4-propylcyclohexane (PCH3) in the liquid crystalline and isotropic phases were observed under microwave irradiation. When the temperature was regulated at slightly higher than the phase transition temperature (Tc = 45 °C) under a gas flow temperature control system, liquid crystalline phase mostly changed to the isotropic phase. Under microwave irradiation and with the gas flow temperature maintained at 20 °C, which is 25 °C below the Tc, the isotropic phase appeared stationary as an approximately 2% fraction in the liquid crystalline phase. The temperature of the liquid crystalline state was estimated to be 38 °C according to the line width, which is at least 7 °C lower than the Tc. The temperature of this isotropic phase should be higher than 45 °C, which is considered to be a non-equilibrium local heating state induced by microwave irradiation. Microwaves at a power of 195 W were irradiated to the isotropic phase of PCH3 at 50 °C and after 2 min, the temperature reached 220 °C. The temperature of PCH3 under microwave irradiation was estimated by measurement of the chemical shift changes of individual protons in the molecule. These results demonstrate that microwave heating generates very high temperature within a short time using an in situ microwave irradiation NMR spectrometer.

  9. Nanosize Mn{sub 3}O{sub 4} (Hausmannite) by microwave irradiation method

    SciTech Connect

    Apte, S.K.; Naik, S.D.; Sonawane, R.S.; Kale, B.B. . E-mail: kbbb1@yahoo.com; Pavaskar, Neela; Mandale, A.B.; Das, B.K.

    2006-03-09

    The present investigation reports, the novel synthesis of nanosize Mn{sub 3}O{sub 4} powder with nanorods using microwaves and its physicochemical characterization. The nanosize Mn{sub 3}O{sub 4} powder has been prepared using manganese nitrate as a precursor and effect of ethanolamine and ethylenediamine on particle morphology has been studied. The microwave irradiation has been carried out in the range 50-500 W and it was observed that formation of Mn{sub 3}O{sub 4} takes place at 50 W. TEM analysis demonstrated nanosize Mn{sub 3}O{sub 4} powder and nanorods with an average diameter of about 10 nm. The structural study by XRD indicates that these nano-powders have pure tetragonal phase. The phase pure samples were characterized using X-Ray Photoelectron Spectroscopy (XPS) for both Mn 2p and Mn 3s levels. The values of binding energies are consistent with the relative values reported in the literature. The metallic impurity levels have been characterized using Inductively Coupled Plasma-Optical Emission Spectrophotometer (ICP-OES)

  10. Fast and Controllable Crystallization of Perovskite Films by Microwave Irradiation Process.

    PubMed

    Cao, Qipeng; Yang, Songwang; Gao, Qianqian; Lei, Lei; Yu, Yu; Shao, Jun; Liu, Yan

    2016-03-30

    The crystal growth process significantly influences the properties of organic-inorganic halide perovskite films along with the performance of solar cell devices. In this paper, we adopted the microwave irradiation to treat perovskite films through a one-step deposition method for several minutes at a fixed output power. It is found that the specific microwave irradiation process can evaporate the solvent directly and heat perovskite film quickly. In comparison with the conventional thermal annealing process, a microwave irradiation process assisted fast and controllable crystallization of perovskite films with less energy-loss and time-consumption and therefore resulted in the enhancement in the photovoltaic performance of the corresponding solar cells. PMID:26963524

  11. Observation of bubble formation in water during microwave irradiation by dynamic light scattering

    NASA Astrophysics Data System (ADS)

    Asakuma, Yusuke; Munenaga, Takuya; Nakata, Ryosuke

    2015-10-01

    A microwave reactor was designed for in situ observation of nano- and micro-bubbles, and size profiles during and after irradiation were measured with respect to irradiation power and time. Bubble formation in water during irradiation was observed even at temperatures below the boiling point of water. The maximum size strongly depended on radiation power and time, even at a given temperature. Nano-particles in the dispersion medium were found to play an important role in achieving more stable nucleation of bubbles around particles, and stable size distributions were obtained from clear autocorrelation by a dynamic light scattering system. Moreover, a combination of microwave induction heating and the addition of nano-particles to the dispersion medium can prevent heterogeneous nucleation of bubbles on the cell wall. Quantitative nano-bubble size profiles obtained by in situ observation provide useful information regarding microwave-based industrial processes for nano-particle production.

  12. Effects of Electron Beam and Microwave Irradiation on Human Blood Proteins

    SciTech Connect

    Martin, Diana I.; Craciun, Gabriela D.; Manaila, Elena N.; Ighigeanu, Daniel I.; Iacob, Nicusor I.; Oproiu, Constantin V.; Stan, Dana E.; Radu, Roxana R.; Margaritescu, Irina D.; Chirita, Doru I.

    2007-04-23

    The effects of separated and combined accelerated electron beam (EB) of 6.23 MeV and microwave (MW) of 2.45GHz irradiation on proteins in samples of human serum, human plasma and human integral blood are presented. Also, it was studied the effect of separate and combined EB and MW irradiation on proteins irradiated in samples of human integral blood, without and in the presence of a synthetic compound solution (S.C.S.) which is expected to exhibit various biological actions, such as to diminish or to increase the irradiation effects.

  13. ‘GREENER’ CHEMICAL SYNTHESES USING MICROWAVE IRRADIATION (PRAGUE)

    EPA Science Inventory

    'Greener' solvent-free protocols involve microwave (MW) exposure of neat reactants catalyzed by the surfaces of recyclable mineral supports such as alumina, silica and clay which are applicable to a wide range of cleavage, condensation, cyclization, oxidation and reduction reacti...

  14. EFFICIENT AND GREENER CHEMICAL SYNTHESES USING MICROWAVE IRRADIATION

    EPA Science Inventory

    The diverse nature of chemical entities requires various ‘green’ strategic pathways in our quest towards attaining sustainability. A solvent-free approach involving microwave (MW) exposure of neat reactants (undiluted) catalyzed by the surfaces of less-expensive and rec...

  15. Effect of Microwave Irradiation on the Physicochemical and Digestive Properties of Lotus Seed Starch.

    PubMed

    Zeng, Shaoxiao; Chen, Bingyan; Zeng, Hongliang; Guo, Zebin; Lu, Xu; Zhang, Yi; Zheng, Baodong

    2016-03-30

    The objective of this study is to investigate the effect of microwave irradiation on the physicochemical and digestive properties of lotus seed starch. The physicochemical properties of lotus seed starch were characterized by light microscopy, (1)H NMR, FT-IR spectroscopy, and HPSEC-MALLS-RI. The starch-water interaction and crystalline region increased due to the changed water distribution of starch granules and the increase of the double-helix structure. The swelling power, amylose leaching, molecular properties, and radius of gyration reduced with the increasing microwave power, which further affected the sensitivity of lotus seed starch to enzymatic degradation. Furthermore, the resistant starch and slowly digestible starch increased with the increasing microwave irradiation, which further resulted in their decreasing hydrolysis index and glycemic index. The digestive properties of lotus seed starch were mainly influenced by the reduced branching degree of amylopectin and the strong amylose-amylose interaction. PMID:26912092

  16. Method of producing carbon monoxide and hydrogen by gasification of solid carbonaceous material involving microwave irradiation

    SciTech Connect

    Helm, J.L. Jr.

    1984-03-06

    A process is claimed for the gasification of carbon of solid carbonaceous material to form carbon monoxide and hydrogen by contacting the material with superheated steam and irradiating the product of said contacting with an amount of microwave energy sufficient to gasify said carbon, and apparatus therefor.

  17. ASSESSMENT OF IMMUNE FUNCTION DEVELOPMENT IN MICE IRRADIATED IN UTERO WITH 2450-MHZ MICROWAVES

    EPA Science Inventory

    Groups of time-bred pregnant mice were irradiated with 2450-MHz microwaves at an incident power density of 28 mW/sq. cm. for 100 min daily from day 6 to day 18 of pregnancy. The average specific absorption rate (SAR) was 16.5 W/kg. Two experiments were performed under these condi...

  18. CHEMISTRY UNDER 'GREENER' CONDITIONS: SOLVENT-FREE SYNTHESIS USING MICROWAVE IRRADIATION

    EPA Science Inventory

    Solvent-free approach is emphasized that involves microwave (MW) irradiation of neat reactants (undiluted) catalyzed by the surfaces of less-expensive and recyclable mineral supports such as alumina, silica, clay, or 'doped' surfaces which is applicable to a wide range of cleavag...

  19. NOVEL METALLIC AND BIMETALLIC CROSS-LINKED POLY (VINYL ALCOHOL) NANOCOMPOSITES PREPARED UNDER MICROWAVE IRRADIATION

    EPA Science Inventory

    A facile microwave irradiation approach that results in a cross-linking reaction of poly (vinyl alcohol) (PVA) with metallic and bimetallic systems is described. Nanocomposites of PVA cross-linked metallic systems such as Pt, Cu, and In and bimetallic systems such as Pt-In, Ag-P...

  20. "GREENER" CHEMICAL SYNTHETIC PROCESSES USING ENZYMATIC, MECHANOCHEMICAL MIXING, OR MICROWAVE AND ULTRASOUND IRRADIATION

    EPA Science Inventory

    Several newer strategies, such as solvent-free (dry media), solid-supported with and without microwave (MW) irradiation, and mechanochemical mixing (grinding); and the use of room temperature ionic liquids, supercritical carbon dioxide, and water as reaction media that can be com...

  1. CHEMISTRY UNDER NON-TRADITIONAL CONDITIONS: SOLVENT-FREE SYNTHESIS USING MICROWAVE IRRADIATION

    EPA Science Inventory

    A solvent-free approach that involves microwave (MW) irradiation of neat reactants (undiluted) catalyzed by the surfaces of less-expensive and recyclable mineral supports such as alumina, silica, clay, or "doped" surfaces is presented which is applicable to a wide range of cleava...

  2. Green synthesis of noble nanometals (Au, Pt, Pd) using glycerol under microwave irradiation conditions

    EPA Science Inventory

    A newer application of glycerol in the field of nanomaterials synthesis has been developed from both the economic and environmental points of view. Glycerol can act as a reducing agent for the fabrication of noble nanometals, such as Au, Pt, and Pd, under microwave irradiation. T...

  3. Microwave oven irradiation as a method for bacterial decontamination in a clinical microbiology laboratory.

    PubMed

    Latimer, J M; Matsen, J M

    1977-10-01

    Exposure of 10 frequently isolated clinical pathogens to microwave irradiation resulted in total sterilization with 60 s. Time exposure experiments done with commercially prepared test strips containing Bacillus stearothermophilus spores indicated that 5-min exposure was adequate to insure sterility of small, contaminated loads. PMID:410828

  4. A microwave applicator for uniform irradiation by circularly polarized waves in an anechoic chamber.

    PubMed

    Chiang, W Y; Wu, M H; Wu, K L; Lin, M H; Teng, H H; Tsai, Y F; Ko, C C; Yang, E C; Jiang, J A; Barnett, L R; Chu, K R

    2014-08-01

    Microwave applicators are widely employed for materials heating in scientific research and industrial applications, such as food processing, wood drying, ceramic sintering, chemical synthesis, waste treatment, and insect control. For the majority of microwave applicators, materials are heated in the standing waves of a resonant cavity, which can be highly efficient in energy consumption, but often lacks the field uniformity and controllability required for a scientific study. Here, we report a microwave applicator for rapid heating of small samples by highly uniform irradiation. It features an anechoic chamber, a 24-GHz microwave source, and a linear-to-circular polarization converter. With a rather low energy efficiency, such an applicator functions mainly as a research tool. This paper discusses the significance of its special features and describes the structure, in situ diagnostic tools, calculated and measured field patterns, and a preliminary heating test of the overall system. PMID:25173291

  5. A microwave applicator for uniform irradiation by circularly polarized waves in an anechoic chamber

    SciTech Connect

    Chiang, W. Y.; Wu, M. H.; Wu, K. L.; Lin, M. H.; Teng, H. H.; Barnett, L. R.; Chu, K. R.; Tsai, Y. F.; Ko, C. C.; Yang, E. C.; Jiang, J. A.

    2014-08-15

    Microwave applicators are widely employed for materials heating in scientific research and industrial applications, such as food processing, wood drying, ceramic sintering, chemical synthesis, waste treatment, and insect control. For the majority of microwave applicators, materials are heated in the standing waves of a resonant cavity, which can be highly efficient in energy consumption, but often lacks the field uniformity and controllability required for a scientific study. Here, we report a microwave applicator for rapid heating of small samples by highly uniform irradiation. It features an anechoic chamber, a 24-GHz microwave source, and a linear-to-circular polarization converter. With a rather low energy efficiency, such an applicator functions mainly as a research tool. This paper discusses the significance of its special features and describes the structure, in situ diagnostic tools, calculated and measured field patterns, and a preliminary heating test of the overall system.

  6. A microwave applicator for uniform irradiation by circularly polarized waves in an anechoic chamber

    NASA Astrophysics Data System (ADS)

    Chiang, W. Y.; Wu, M. H.; Wu, K. L.; Lin, M. H.; Teng, H. H.; Tsai, Y. F.; Ko, C. C.; Yang, E. C.; Jiang, J. A.; Barnett, L. R.; Chu, K. R.

    2014-08-01

    Microwave applicators are widely employed for materials heating in scientific research and industrial applications, such as food processing, wood drying, ceramic sintering, chemical synthesis, waste treatment, and insect control. For the majority of microwave applicators, materials are heated in the standing waves of a resonant cavity, which can be highly efficient in energy consumption, but often lacks the field uniformity and controllability required for a scientific study. Here, we report a microwave applicator for rapid heating of small samples by highly uniform irradiation. It features an anechoic chamber, a 24-GHz microwave source, and a linear-to-circular polarization converter. With a rather low energy efficiency, such an applicator functions mainly as a research tool. This paper discusses the significance of its special features and describes the structure, in situ diagnostic tools, calculated and measured field patterns, and a preliminary heating test of the overall system.

  7. In situ temperature measurements of reaction spaces under microwave irradiation using photoluminescent probes.

    PubMed

    Ano, Taishi; Kishimoto, Fuminao; Sasaki, Ryo; Tsubaki, Shuntaro; Maitani, Masato M; Suzuki, Eiichi; Wada, Yuji

    2016-05-11

    We demonstrate two novel methods for the measurement of the temperatures of reaction spaces locally heated by microwaves, which have been applied here to two example systems, i.e., BaTiO3 particles covered with a SiO2 shell (BaTiO3-SiO2) and layered tungstate particles. Photoluminescent (PL) probes showing the temperature-sensitivity in their PL lifetimes are located in the nanospaces of the above systems. In the case of BaTiO3-SiO2 core-shell particles, rhodamine B is loaded into the mesopores of the SiO2 shell covering the BaTiO3 core, which generates the heat through the dielectric loss of microwaves. The inner nanospace temperature of the SiO2 shell is determined to be 28 °C higher than the bulk temperature under microwave irradiation at 24 W. On the other hand, Eu(3+) is immobilized in the interlayer space of layered tungstate as the PL probe, showing that the nanospace temperature of the interlayer is only 4 °C higher than the bulk temperature. This method for temperature-measurement is powerful for controlling microwave heating and elucidates the ambiguous mechanisms of microwave special effects often observed in chemical reactions, contributing greatly to the practical application of microwaves in chemistry and materials sciences. PMID:27136754

  8. Effect of microwave irradiation on the photoluminescence of bound excitons in CdTe:Cl single crystals

    SciTech Connect

    Korbutyak, D. V.; Lotsko, A. P.; Vakhnyak, N. D.; Demchuna, L. A.; Konakova, R. V. Milenin, V. V.; Red'ko, R. A.

    2011-09-15

    The effect of microwave radiation on the transformation of impurity-based structural complexes in Cd{sub Te}:Cl single crystals is studied using low-temperature photoluminescence measurements. It is shown that microwave radiation activates Cl{sub Te} centers, resulting in an increase in the intensity of photoluminescence line of excitons bound at the corresponding Cl{sub Te} donor centers. A nonmonotonic dependence of the integrated photoluminescence intensity on the duration of microwave irradiation is observed. At the initial stage of microwave irradiation (t = 30 s), an increase in the integrated excitonic photoluminescence intensity is observed; as the duration of microwave irradiation is increased, the photoluminescence intensity decreases. The experimentally observed variations in the photoluminescence intensity are athermal in nature. The hypothetical mechanism of transformation of impurity-based structural complexes is described.

  9. A microwave-irradiated Streptococcus agalactiae vaccine provides partial protection against experimental challenge in Nile tilapia, Oreochromis niloticus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Microwave irradiation, as opposed to formalin exposure, has not routinely been used in the preparation of killed vaccines despite the advantages of decreased chemical toxicity, ability to kill cells quickly, ease of completion requiring only a standard microwave, and potential increased protein cons...

  10. Preparation of starch-poly-glutamic acid graft copolymers by microwave irradiation and the characterization of their properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Graft copolymers of waxy maize starch and poly-y-glutamic acid (PGA) were produced in an aqueous solution using microwave irradiation. The microwave reaction conditions were optimized with regard to temperature and pH. The temperature of 180 deg C and pH 7.0 were the best reaction conditions resulti...

  11. Acute microwave irradiation and cataract formation in rabbits and monkeys.

    PubMed

    Kramar, P; Harris, C; Emery, A F; Guy, A W

    1978-09-01

    Rabbits and monkeys were irradiated in the near field of a cavity-backed 2450 MHz resonant slot radiator, to determine the cataractogenic threshold. Rabbits developed cataracts at incident "apparent" power densities of 180 mW/cm2 (E2/120 pi, where E=rms/electric field strength). Monkeys sustained facial burns, but no lens damage, even at incident "apparent" power densities of 500 mW/cm2. These results were substantiated by computer thermal models. PMID:108401

  12. Whole Body Microwave Irradiation for Improved Dacarbazine Therapeutical Action in Cutaneous Melanoma Mouse Model

    PubMed Central

    Albulescu, Lucian; Iacob, Nicusor; Ighigeanu, Daniel

    2013-01-01

    A cutaneous melanoma mouse model was used to test the efficacy of a new therapeutical approach that uses low doses of cytostatics in conjunction with mild whole body microwave exposure of 2.45 GHz in order to enhance cytostatics antitumoral effect. Materials and Methods. A microwave exposure system for C57BL/6 mouse whole body microwave irradiation was designed; groups of 40 mice (males and females) bearing experimental tumours were subjected to a combined therapy comprising low doses of dacarbazine in combination with mild whole body irradiation. Clinical parameters and serum cytokine testing using xMAP technology were performed. Results. The group that was subjected to combined therapy, microwave and cytostatic, had the best clinical evolution in terms of overall survival, tumour volume, and metastatic potential. At day 14 the untreated group had 100% mortality, while in the combined therapy group 40% of mice were surviving. Quantifying serum IL-1β, IL-6, IL-10, IL-12 (p70), IFN-γ, GM-CSF, TNF-α, MIP-1α, MCP-1, and KC during tumorigenesis and therapy found that the combined experimental therapy decreases all the inflammatory cytokines, except chemokine MCP-1 that was found increased, suggesting an increase of the anti-tumoral immune response triggered by the combined therapy. The overall metastatic process is decreased in the combined therapy group. PMID:24377047

  13. Rapid Synthesis and Antiviral Activity of (Quinazolin-4-Ylamino)Methyl-Phosphonates Through Microwave Irradiation

    PubMed Central

    Luo, Hui; Hu, Deyu; Wu, Jian; He, Ming; Jin, Linhong; Yang, Song; Song, Baoan

    2012-01-01

    This study describes the simple synthesis of new (quinazolin-4-ylamino) methylphosphonates via microwave irradiation. Substituted-2-aminobenzonitrile reacted with 1,1-dimethoxy-N,N-dimethylmethanamine at a reflux condition to obtain N′-(substituted-2-cyanophenyl)-N,N-dimethylformamidine (1). The subsequent reaction of this intermediate product with α-aminophosphonate (2) in a solution containing glacial acetic acid in 2-propanol through microwave irradiation resulted in the formation of (quinazolin-4-ylamino)methyl-phosphonate derivatives 3a to 3x, which were unequivocally characterized by the spectral data and elemental analysis. The influence of the reaction conditions on the yield of 3a was investigated to optimize the synthetic conditions. The relative optimal conditions for the synthesis of 3a include a 1:1 molar ratio of N′-(2-cyanophenyl)-N,N-dimethylformamidine to diethyl amino(phenyl)methylphosphonate and a 4:1 volume ratio of isopropanol to HOAc in the solvent mixture, at a reaction temperature of 150 °C, with a microwave power of 100 W and a corresponding pressure of 150 psi for 20 min in the microwave synthesizer. The yield of 3a was approximately 79%, whereas those of 3b to 3x were approximately 77% to 86%. Some of the synthesized compounds displayed weak to good anti-Tobacco mosaic virus (TMV) activity. PMID:22837660

  14. Resonant Phase Escape from the First Resistive State of Bi2Sr2CaCu2Oy Intrinsic Josephson Junctions under Strong Microwave Irradiation

    NASA Astrophysics Data System (ADS)

    Takahashi, Yusaku; Kakehi, Daiki; Takekoshi, Shuho; Ishikawa, Kazuki; Ayukawa, Shin-ya; Kitano, Haruhisa

    2016-07-01

    We report a study of the phase escape in Bi2Sr2CaCu2Oy intrinsic Josephson junctions under the strong microwave irradiation, focusing on the switch from the first resistive state (2nd SW). The resonant double-peak structure is clearly observed in the switching current distributions below 10 K and is successfully explained by a quantum-mechanical model on the quantum phase escape under the strong microwave field. These results provide the first evidence for the formation of the energy level quantization for the 2nd SW, supporting that the macroscopic quantum tunneling for the 2nd SW survives up to ˜10 K.

  15. Artificial and enhanced humification of soil organic matter using microwave irradiation.

    PubMed

    Kim, Min Chan; Kim, Han S

    2013-04-01

    Microwave (MW) irradiation, a less energy-intensive irradiation technique, was employed to promote the changes in physicochemical properties of soil organic matter (SOM). MW was irradiated to forest soils for 10 min. Then, the physical and chemical properties of the SOM were analyzed with UV absorbance spectroscopy, Fourier transform infrared spectroscopy, elemental analysis, and size exclusion chromatography. Also, the SOM was fractionated into biopolymer, fulvic acid, and humic acid, and each fraction was analyzed quantitatively. These analyses revealed that the SOM became more aromatic and nonpolar, highly condensed, and macromolecular organic substances that possess a higher amount of functional groups found in highly humified substances than the original SOM as a result of the MW irradiation. The humification-like alteration of SOM property was attributable to the thermal cracking and to the radical reaction, particularly when the MW was irradiated along with activated carbon under the aerobic condition. The results of this study suggest that the artificial and enhanced property changes of SOM can be accomplished by MW irradiation on an engineering time scale, which can contribute to the successful soil and groundwater remediation practice. PMID:22895631

  16. Degradation of N-nitrosodimethylamine (NDMA) and its precursor dimethylamine (DMA) in mineral micropores induced by microwave irradiation.

    PubMed

    He, Yuanzhen; Cheng, Hefa

    2016-05-01

    Removal of N-nitrosodimethylamine (NDMA) in drinking water treatment poses a significant technical challenge due to its small molecular size, high polarity and water solubility, and poor biodegradability. Degradation of NDMA and its precursor, dimethylamine (DMA), was investigated by adsorbing them from aqueous solution using porous mineral sorbents, followed by destruction under microwave irradiation. Among the mineral sorbents evaluated, dealuminated ZSM-5 exhibited the highest sorption capacities for NDMA and DMA, which decreased with the density of surface cations present in the micropores. In contrast, the degradation rate of the sorbed NDMA increased with the density of surface cations under microwave irradiation. Evolutions of the degradation products and C/N ratio indicate that the sorbed NDMA and DMA could be eventually mineralized under continuous microwave irradiation. The degradation rate was strongly correlated with the bulk temperature of ZSM-5 and microwave power, which is consistent with the mechanism of pyrolysis caused by formation of micro-scale "hot spots" within the mineral micropores under microwave irradiation. Compared to existing treatment options for NDMA removal, microporous mineral sorption coupled with microwave-induced degradation has the unique advantages of being able to simultaneously remove NDMA and DMA and cause their full mineralization, and thus could serve as a promising alternative method. PMID:26971806

  17. Enhanced biocatalysis mechanism under microwave irradiation in isoquercitrin production revealed by circular dichroism and surface plasmon resonance spectroscopy.

    PubMed

    Gong, An; Zhu, Dan; Mei, Yi-Yuan; Xu, Xiao-Hui; Wu, Fu-An; Wang, Jun

    2016-04-01

    An efficient and rapid process for isoquercitrin production by hesperidinase-catalyzed hydrolysis of rutin was successfully developed under microwave irradiation detecting the affinity by circular dichroism (CD) and surface plasmon resonance (SPR) spectroscopy. A maximum isoquercitrin yield of 91.5±2.7% was obtained in 10min with the conditions of 10g/L hesperidinase, 2g/L rutin, 30°C and microwave power density 88.9W/L. Enzymatic reaction rate and Vm/Km in the microwave reactor were 6.34-fold higher than in a continuous flow microreactor and 1.24-fold higher than in a biphasic system. CD and SPR analysis results also showed that hesperidinase has a better selectivity and affinity (3.3-fold than in a batch reactor) to generate isoquercitrin under microwave irradiation. Microwave irradiation greatly improved the reaction efficiency and productivity, leading to a more positive economical assessment. The binding affinity indicates the presence of strong multivalent interactions between rutin and hesperidinase under microwave irradiation. PMID:26803794

  18. Effects of microwave irradiation on dewaterability and extracellular polymeric substances of waste activated sludge.

    PubMed

    Peng, Ge; Ye, Fenxia; Ye, Yangfang

    2013-03-01

    The effects of microwave irradiation on filterability and dewaterability of waste activated sludge measured by capillary suction time (CST) and dry solids in sludge cake were investigated. The results showed that the optimum irradiation time improved filterability, but that further increase of the time was detrimental. Dewaterability was enhanced significantly and increased with microwave time. Filterability and dewaterability were improved 25 to 28% and 1.3 times at the optimum times of 30 and 90 seconds for the sludge of 5 g total suspended solids (TSS)/L and 7 g TSS/L, respectively. The floc size decreased slightly. Loosely bound extracellular polymeric substances (LB-EPS) decreased under optimum time, but tightly bound extracellular polymeric substances did not change significantly after short irradiation time. The results implied that LB-EPS played a more important role in the observed changes of filterability and dewaterability and that the double-layered extracellular polymeric substances extraction method showed marked implications to dewaterability. PMID:23581243

  19. Synthesis and characterization of some metal oxide nanocrystals by microwave irradiation

    SciTech Connect

    Rashad, M.; Gaber, A.; Abdelrahim, M. A.; Abdel-Baset, A. M.; Moharram, A. H.

    2013-12-16

    Copper oxide and cobalt oxide (CuO, Co3O4) nanocrystals (NCs) have been successfully prepared in a short time using microwave irradiation. The resulted powders of nanocrystals (NCs) were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Thermogravimetric analysis (TGA) measurements are also studied. Fourier-transform infrared (FT-IR) and UV–visible absorption spectroscopy of both kind of nanoparticels are illustrated. Optical absorption analysis indicated the direct band gap for both kinds of nanocrystals.

  20. Microwave irradiation of human brain tissue: production of microscopic slides within one day.

    PubMed Central

    Boon, M E; Marani, E; Adriolo, P J; Steffelaar, J W; Bots, G T; Kok, L P

    1988-01-01

    A three step method using microwave irradiation enabled microscopic slides of human brain tissue to be obtained within one working day: steps 1 and 2 hardened and solidified brain tissue; step 3 completed formalin fixation. The efficacy and precision of the method was compared with slides of conventionally processed brain tissue that had been fixed in formalin for six weeks. The microscopic quality of the sections was excellent with good presentation of brain tissue and equalled that of conventionally processed slides. Images Fig 1 Fig 2 Fig 3 PMID:3290268

  1. Enhancing the various solvent extraction method via microwave irradiation for extraction of lipids from marine microalgae in biodiesel production.

    PubMed

    Teo, Chee Loong; Idris, Ani

    2014-11-01

    The types of microalgae strains and the method used in lipid extraction have become crucial factors which influence the productivity of crude oil. In this paper, Nannochloropsis sp. and Tetraselmis sp. were chosen as the strains and four different methods were used to extract the lipids: Hara and Radin, Folch, Chen and Bligh and Dyer. These methods were performed by using conventional heating and microwave irradiation methods. Results revealed that highest lipid yield from the different species was obtained using different extraction methods; both under microwave irradiation. The lipid yield for Tetraselmis sp. and Nannochloropsis sp. was highest when Hara and Radin (8.19%), and Folch (8.47%) methods were used respectively under microwave irradiation. The lipids extracted were then transesterified to biodiesel and the quality of the biodiesel was analyzed using the gas chromatography. PMID:25201293

  2. Preparation and characterization of guluronic acid oligosaccharides degraded by a rapid microwave irradiation method.

    PubMed

    Hu, Ting; Li, Chunxia; Zhao, Xia; Li, Guangsheng; Yu, Guangli; Guan, Huashi

    2013-05-24

    Guluronic acid oligosaccharides (GOS) with degree of polymerization (DP) ranging from 1 to 10 were prepared by a rapid microwave degradation method. Polyguluronic acid, fractionated from alginate hydrolysate, was dissolved in dilute ammonia water at a concentration of 20 mg/mL (pH 5) and then hydrolyzed under microwave irradiation (1600 W) at 130°C for 15 min to produce GOS mixture. The GOS mixture was separated by a Bio-Gel P6 column and ten fractions were obtained. Each GOS fraction was further characterized by electrospray ionization mass spectrometry, (1)H NMR, (13)C NMR, and 2D NMR spectroscopy techniques. The data showed that the GOS fractions were saturated oligoguluronates with general molecular formula C(6n)H(8n+2)O(6n+1) (n=1-10). This microwave degradation method was not only convenient, less time consuming, and environment-friendly, but also produced GOS with high yield (71%) and eliminating a desalting procedure compared to conventional acid hydrolysis method. PMID:23584235

  3. An efficient combination of Zr-MOF and microwave irradiation in catalytic Lewis acid Friedel-Crafts benzoylation.

    PubMed

    Doan, Tan L H; Dao, Thong Q; Tran, Hai N; Tran, Phuong H; Le, Thach N

    2016-05-01

    A zirconium-based metal-organic framework, an effective heterogeneous catalyst, has been developed for the Friedel-Crafts benzoylation of aromatic compounds under microwave irradiation. Constructed by a Zr(iv) cluster and a linker 1,4-bis(2-[4-carboxyphenyl]ethynyl)benzene (H2CPEB), the MOF, possessing large pores and high chemical stability, was appropriate for the enhancement of Lewis acid activity under microwave irradiation. The reaction studies demonstrated that the material could give high yields for a few minutes and maintain its reactivity and structure over several cycles. PMID:27064371

  4. Controlled synthesis of snowflake-like self-assemblies palladium nanostructures under microwave irradiation

    SciTech Connect

    Xie, Ting; Ma, Yue; Yang, Hanmin Li, Jinlin

    2013-08-01

    Graphical abstract: - Highlights: • We demonstrated the synthesis of snowflake-like palladium nanostructures for the first time. • We discussed the influencing factors on the synthesis of snowflake-like Pd nanostructures. • The molar ratio of H{sub 2}Pd{sub 4} to PVP at 5 is the optimal selection. • The growth process was discussed. - Abstract: Self-assembly snowflake-like palladium nanostructures were synthesized under microwave irradiation using H{sub 2}PdCl{sub 4} as precursor, benzyl alcohol as both solvent and reducing agent, and PVP as stabilizer. The Pd snowflake-like nanostructures were formed and then characterized by transmission electron microscopy (TEM) and X-ray powder diffraction. The TEM images showed that the Pd nano-snowflakes were self-assemblies organized by hundreds of small spherical nanoparticles. Pd snowflake-like nanostructures with well-defined shape and uniform size can be obtained by tuning the concentration of palladium precursor, the molar ratio of H{sub 2}PdCl{sub 4}/PVP, as well as the heating time by microwave irradiation. The possible growing process of the snowflake-like Pd structures was also proposed on the basis of investigating the properties of as-synthesized Pd nanostructures under different conditions.

  5. Influence of microwave irradiation on the mass-transfer kinetics of propylbenzene in reversed-phase liquid chromatography

    SciTech Connect

    Galinada, Wilmer; Kaczmarski, Krzysztof; Guiochon, Georges A

    2005-09-01

    The effect of microwave irradiation on the kinetics of mass transfer in reversed-phase liquid chromatography (RPLC) was studied by measuring its influence on the band profile of propylbenzene in a C{sub 18}-silica column eluted with an aqueous solution of methanol and placed inside a microwave oven. The elution peaks were measured by the pulse-response method, under linear conditions. The amount of microwave energy induced into the column was varied based on the microwave input power. The experimental data were analyzed using the conventional method of moment analysis and the lumped pore diffusion model. With input powers of 15 and 30 W, the effluent temperatures were 25 {+-} 1 and 30 {+-} 1 C, respectively. The effect of microwave irradiation on the mass transfer of the studied solute was determined by comparing the band profiles obtained under the same experimental conditions, at the same temperature, with and without irradiation. The values of the intraparticle diffusion coefficient, D{sub e}, measured with microwave irradiation were ca. 20% higher than those obtained without irradiation. Derived from the method of moments, the values of D{sub e} at 15 W (25 {+-} 1 C) and 0 W (25 {+-} 1 C) were 8.408 x 10{sup -6} cm{sup 2} s{sup -1} and 6.947 x 10{sup -6} cm{sup 2} s{sup -1}, respectively, while these values at 30 W (30 {+-} 1 C) and 0 W (30 {+-} 1 C) were 9.389 x 10{sup -6} cm{sup 2} s{sup -1} and 7.848 x 10{sup -6} cm{sup 2} s{sup -1}, respectively. The values of the surface diffusivity, D{sub S}, also increased with increasing power of the microwave irradiation. It is assumed that the increase in intraparticle diffusion for propylbenzene was caused by the molecular excitation of the organic modifier that has a higher dielectric loss than the solute. The values of D{sub e} were also analyzed and determined using the POR model. There was an excellent agreement between the results of the two independent methods. These preliminary results suggest that microwave

  6. Microwave energy for post-calcination treatment of high-level nuclear wastes

    SciTech Connect

    Gombert, D.; Priebe, S.J.; Berreth, J.R.

    1980-01-01

    High-level radioactive wastes generated from nuclear fuel reprocessing require treatment for effective long-term storage. Heating by microwave energy is explored in processing of two possible waste forms: (1) drying of a pelleted form of calcined waste; and (2) vitrification of calcined waste. It is shown that residence times for these processes can be greatly reduced when using microwave energy rather than conventional heating sources, without affecting product properties. Compounds in the waste and in the glass frit additives couple very well with the 2.45 GHz microwave field so that no special microwave absorbers are necessary.

  7. Photocatalytic Decomposition of Methylene Blue Over MIL-53(Fe) Prepared Using Microwave-Assisted Process Under Visible Light Irradiation.

    PubMed

    Trinh, Nguyen Duy; Hong, Seong-Soo

    2015-07-01

    Iron-based MIL-53 crystals with uniform size were successfully synthesized using a microwave-assisted solvothermal method and characterized by XRD, FE-SEM and DRS. We also investigated the photocatalytic activity of MIL-53(Fe) for the decomposition of methylene blue using H2O2 as an electron acceptor. From XRD and SEM results, the fully crystallized MIL-53(Fe) materials were obtained regardless of preparation method. From DRS results, MIL-53(Fe) samples prepared using microwave-assisted process displayed the absorption spectrum up to the visible region and then they showed the high photocatalytic activity under visible light irradiation. The MIL-53(Fe) catalyst prepared by two times microwave irradiation showed the highest activity. PMID:26373158

  8. Ionic liquid as a promising biobased green solvent in combination with microwave irradiation for direct biodiesel production.

    PubMed

    Wahidin, Suzana; Idris, Ani; Shaleh, Sitti Raehanah Muhamad

    2016-04-01

    The wet biomass microalgae of Nannochloropsis sp. was converted to biodiesel using direct transesterification (DT) by microwave technique and ionic liquid (IL) as the green solvent. Three different ionic liquids; 1-butyl-3-metyhlimidazolium chloride ([BMIM][Cl], 1-ethyl-3-methylimmidazolium methyl sulphate [EMIM][MeSO4] and 1-butyl-3-methylimidazolium trifluoromethane sulfonate [BMIM][CF3SO3]) and organic solvents (hexane and methanol) were used as co-solvents under microwave irradiation and their performances in terms of percentage disruption, cell walls ruptured and biodiesel yields were compared at different reaction times (5, 10 and 15 min). [EMIM][MeSO4] showed highest percentage cell disruption (99.73%) and biodiesel yield (36.79% per dried biomass) after 15 min of simultaneous reaction. The results demonstrated that simultaneous extraction-transesterification using ILs and microwave irradiation is a potential alternative method for biodiesel production. PMID:26851899

  9. Phenolic Content and Antioxidant Activity of Extracts from Whole Buckwheat (Fagopyrum esculentum Moench) With or Without Microwave Irradiation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The purpose of this study was to evaluate the effectiveness of extracting phenolic compounds and antioxidant activity from buckwheat with water, 50% aqueous ethanol, or 100% ethanol using microwave irradiation or a water bath for 15 min at various temperatures (23 – 150 °C). The phenolic content of...

  10. Microwave emission by nonlinear crystals irradiated with a high-intensity, mode-locked laser

    NASA Astrophysics Data System (ADS)

    Borghesani, A. F.; Braggio, C.; Guarise, M.

    2016-06-01

    We report on the experimental investigation of the efficiency of some nonlinear crystals to generate microwave (RF) radiation as a result of optical rectification (OR) when irradiated with intense pulse trains delivered by a mode-locked laser at 1064 nm. We have investigated lithium triborate (LBO), lithium niobate (LiNbO3), zinc selenide (ZnSe), and also potassium titanyl orthophosphate (KTP) for comparison with previous measurements. The results are in good agreement with the theoretical predictions based on the form of the second-order nonlinear susceptibility tensor. For some crystals we investigated also the second harmonic generation (SHG) to cross check the theoretical model. We confirm the theoretical prediction that OR leads to the production of higher order RF harmonics that are overtones of the laser repetition rate.

  11. Changes of amino acid gradients in brain tissues induced by microwave irradiation and other means

    SciTech Connect

    Baxter, C.F.; Parsons, J.E.; Oh, C.C.; Wasterlain, C.G.; Baldwin, R.A. )

    1989-09-01

    Focused microwave irradiation to the head (FMI) has been used extensively by neurochemists for rapid inactivation of enzymatic activity in brain tissues and the preservation, for in vitro analysis, of in vivo substrate concentrations. Periodically the suitability of this technique for regional studies has been questioned. Evidence has now been obtained, on the basis of altered concentration gradients for GABA and taurine from the Substantia Nigra (SN) to an Adjacent Dorsal Area (ADJ), that FMI not only inactivates enzymes, but also facilitates rapid diffusion of small molecules from areas of high concentrations to adjacent areas of lower concentration. To a lesser extent, the implantation of plastic injection cannulas also decreased these concentration gradients. These results offer clear evidence that FMI is ill suited and unreliable for studies designed to map and compare the in vivo regional concentrations of diffusible organic molecules (such as amino acids) in brain tissues. Any invasive technique that compromises membrane barriers is likely to produce smaller similar effects.

  12. Biopolymers Regulate Silver Nanoparticle under Microwave Irradiation for Effective Antibacterial and Antibiofilm Activities.

    PubMed

    Velusamy, Palaniyandi; Su, Chia-Hung; Venkat Kumar, Govindarajan; Adhikary, Shritama; Pandian, Kannaiyan; Gopinath, Subash C B; Chen, Yeng; Anbu, Periasamy

    2016-01-01

    In the current study, facile synthesis of carboxymethyl cellulose (CMC) and sodium alginate capped silver nanoparticles (AgNPs) was examined using microwave radiation and aniline as a reducing agent. The biopolymer matrix embedded nanoparticles were synthesized under various experimental conditions using different concentrations of biopolymer (0.5, 1, 1.5, 2%), volumes of reducing agent (50, 100, 150 μL), and duration of heat treatment (30 s to 240 s). The synthesized nanoparticles were analyzed by scanning electron microscopy, UV-Vis spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy for identification of AgNPs synthesis, crystal nature, shape, size, and type of capping action. In addition, the significant antibacterial efficacy and antibiofilm activity of biopolymer capped AgNPs were demonstrated against different bacterial strains, Staphylococcus aureus MTCC 740 and Escherichia coli MTCC 9492. These results confirmed the potential for production of biopolymer capped AgNPs grown under microwave irradiation, which can be used for industrial and biomedical applications. PMID:27304672

  13. Rapid synthesis of gold nanoparticles with Cissus quadrangularis extract using microwave irradiation

    NASA Astrophysics Data System (ADS)

    Bhuvanasree, S. R.; Harini, D.; Rajaram, Anantanarayanan; Rajaram, Rama

    2013-04-01

    The present study focuses on the rapid synthesis of gold nanoparticles (AuNP) using the aqueous extract of Cissus quadrangularis (CQE) by microwave irradiation. The UV-Visible spectroscopy of the solution obtained from reduction of hydrogen tetrachloroaurate (HAuCl4) by CQE revealed a sharp surface plasmon resonance (SPR) peak at 530 nm confirming the presence of AuNP. The formation of AuNP was optimal at a pH of 9. The AuNP was characterised by FT-IR, SEM, HR-TEM, SAED, XRD, TGA, DLS and Zeta potential measurements. The results indicated that microwave assisted synthesis produced well dispersed, small sized, uniform nanoparticles when compared to conventional room temperature synthesis. The spherical nanoparticle had an average size of 12.0 ± 3.2 nm as revealed through TEM. The crystalline nature of AuNP was confirmed through HR-TEM, SAED and XRD. The FT-IR and TGA data revealed the presence of the CQE components on the surface of the AuNP particles which serve as the capping agent. Upon incubation, the particles did not lyse the red blood corpuscles (RBCs) indicating that they are biocompatible. A possible mechanism for the formation of AuNP in the presence of CQE is proposed.

  14. Biopolymers Regulate Silver Nanoparticle under Microwave Irradiation for Effective Antibacterial and Antibiofilm Activities

    PubMed Central

    Velusamy, Palaniyandi; Su, Chia-Hung; Venkat Kumar, Govindarajan; Adhikary, Shritama; Pandian, Kannaiyan; Gopinath, Subash C. B.; Chen, Yeng; Anbu, Periasamy

    2016-01-01

    In the current study, facile synthesis of carboxymethyl cellulose (CMC) and sodium alginate capped silver nanoparticles (AgNPs) was examined using microwave radiation and aniline as a reducing agent. The biopolymer matrix embedded nanoparticles were synthesized under various experimental conditions using different concentrations of biopolymer (0.5, 1, 1.5, 2%), volumes of reducing agent (50, 100, 150 μL), and duration of heat treatment (30 s to 240 s). The synthesized nanoparticles were analyzed by scanning electron microscopy, UV-Vis spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy for identification of AgNPs synthesis, crystal nature, shape, size, and type of capping action. In addition, the significant antibacterial efficacy and antibiofilm activity of biopolymer capped AgNPs were demonstrated against different bacterial strains, Staphylococcus aureus MTCC 740 and Escherichia coli MTCC 9492. These results confirmed the potential for production of biopolymer capped AgNPs grown under microwave irradiation, which can be used for industrial and biomedical applications. PMID:27304672

  15. VUV irradiance measurement of a 2.45 GHz microwave-driven hydrogen discharge

    NASA Astrophysics Data System (ADS)

    Komppula, J.; Tarvainen, O.; Kalvas, T.; Koivisto, H.; Kronholm, R.; Laulainen, J.; Myllyperkiö, P.

    2015-09-01

    Absolute values of VUV-emission of a 2.45 GHz microwave-driven hydrogen discharge are reported. The measurements were performed with a robust and straightforward method based on a photodiode and optical filters. It was found that the volumetric photon emission rate in the VUV-range (80-250 nm) is 1016-1017 cm-3 s-1, which corresponds to approximately 8% dissipation of injected microwave power by VUV photon emission. The volumetric emission of characteristic emission bands was utilized to diagnostics of molecular plasma processes including volumetric rates of ionization, dissociation and excitation to high vibrational levels and metastable states. The estimated reaction rates imply that each injected molecule experiences several inelastic electron impact collisions. The upper limit for the total density of metastable neutrals (2S atoms and {{c}3}{{\\Pi}u} molecules) was estimated to be approximately 0.5% of the neutral gas density.

  16. Microwave-irradiation-assisted hybrid chemical approach for titanium dioxide nanoparticle synthesis: microbial and cytotoxicological evaluation.

    PubMed

    Ranjan, Shivendu; Dasgupta, Nandita; Rajendran, Bhavapriya; Avadhani, Ganesh S; Ramalingam, Chidambaram; Kumar, Ashutosh

    2016-06-01

    Titanium dioxide nanoparticles (TNPs) are widely used in the pharmaceutical and cosmetics industries. It is used for protection against UV exposure due to its light-scattering properties and high refractive index. Though TNPs are increasingly used, the synthesis of TNPs is tedious and time consuming; therefore, in the present study, microwave-assisted hybrid chemical approach was used for TNP synthesis. In the present study, we demonstrated that TNPs can be synthesized only in 2.5 h; however, the commonly used chemical approach using muffle furnace takes 5 h. The activity of TNP depends on the synthetic protocol; therefore, the present study also determined the effect of microwave-assisted hybrid chemical approach synthetic protocol on microbial and cytotoxicity. The results showed that TNP has the best antibacterial activity in decreasing order from Escherichia coli, Bacillus subtilis, and Staphylococcus aureus. The IC50 values of TNP for HCT116 and A549 were found to be 6.43 and 6.04 ppm, respectively. Cell death was also confirmed from trypan blue exclusion assay and membrane integrity loss was observed. Therefore, the study determines that the microwave-assisted hybrid chemical approach is time-saving; hence, this technique can be upgraded from lab scale to industrial scale via pilot plant scale. Moreover, it is necessary to find the mechanism of action at the molecular level to establish the reason for greater bacterial and cytotoxicological toxicity. Graphical abstract A graphical representation of TNP synthesis. PMID:26976013

  17. Evaluation the microwave heating of spinel crystals in high-level waste glass

    SciTech Connect

    Christian, J. H.; Washington, A. L.

    2015-08-18

    In this report, the microwave heating of a crystal-free and a partially (24 wt%) trevorite-crystallized waste glass simulant were evaluated. The results show that a 500 mg piece of partially crystallized waste glass can be heated from room-temperature to above 1600 °C (as measured by infrared radiometry) within 2 minutes using a single mode, highly focused, 2.45 GHz microwave, operating at 300 W. X-ray diffraction measurements show that the partially crystallized glass experiences an 87 % reduction in trevorite following irradiation and thermal quenching. When a crystal-free analogue of the same waste glass simulant composition is exposed to the same microwave radiation it could not be heated above 450 °C regardless of the heating time.

  18. Controlling periodontal bone levels with multiple LED irradiations.

    PubMed

    Chang, Po-Chun; Wang, Chen-Ying; Chong, Li Yen

    2015-02-01

    Because a single exposure to light-emitting diode (LED) irradiation at 660 nm only demonstrated a 3-day biostimulatory effect in recovering periodontal bone level (PBL), this study sought to evaluate whether the periodontal effect could be extended through the use of multiple LED irradiations. Experimental periodontitis was developed unilaterally in 48 Sprague-Dawley rats after the placement of a silk ligature plus Porphyromonas gingivalis lipopolysaccharide injections. The animals were divided into four groups (no irradiation, a single irradiation, or two or three irradiations per week) and exposed to LED light irradiation at a wavelength of 660 ± 25 nm and energy density of 10 J/cm(2) after debridement and detoxification. The animals were euthanized after 7 or 14 days, and the effect of irradiation was evaluated using micro-computed tomography and histology. By day 7, PBL was significantly reduced (p < 0.05), with significantly reduced inflammation (p < 0.05) and gingival hyperplasia (p < 0.001), in the animals receiving three irradiations per week. At day 14, the reduction in gingival hyperplasia was still significant (p < 0.05), and collagen matrix deposition and realignment appeared to be accelerated in the animals receiving three irradiations per week, despite a lack of significant difference in PBL. The treatment regimen receiving three LED light irradiations per week apparently extended the effects in reducing PBL and inflammation to 7 days. The inclusion of additional inflammation control measures or the addition of bioactive signals to mediate the repairing process is necessary to maintain long-term periodontal stability. PMID:23933707

  19. Rapid synthesis and size control of CuInS2 semi-conductor nanoparticles using microwave irradiation

    SciTech Connect

    Gardner, Joseph S.; Shurdha, Endrit; Wang, Chong M.; Lau, Lisa D.; Rodriguez, Rene G.; Pak, Joshua J.

    2008-04-01

    The properties of CuInS2 semi-conductor nanoparticles make them attractive materials for use in next-generation photovoltaics. We have prepared CuInS2 nanoparticles from single source precursors via microwave irradiation. Microwave irradiation methods have allowed us to increase the efficiency of preparation of these materials by providing uniform heating and rapid reaction times. The synergistic effect of varying thiol capping ligand concentrations as well as reaction temperatures and times resulted in fine control of nanoparticle growth in the 3–5 nm size range. Investigation of the photophysical properties of the colloidal nanoparticles were performed using electronic absorption and luminescence emission spectroscopy. Qualitative nanoparticles sizes were determined from the photoluminescence (PLE) data and compared to HRTEM images.

  20. Application of microwave irradiation for the removal of polychlorinated biphenyls from siloxane transformer and hydrocarbon engine oils.

    PubMed

    Antonetti, Claudia; Licursi, Domenico; Raspolli Galletti, Anna Maria; Martinelli, Marco; Tellini, Filippo; Valentini, Giorgio; Gambineri, Francesca

    2016-09-01

    The removal of polychlorinated biphenyls (PCBs) both from siloxane transformer oil and hydrocarbon engine oil was investigated through the application of microwave (MW) irradiation and a reaction system based on polyethyleneglycol (PEG) and potassium hydroxide. The influence of the main reaction parameters (MW irradiation time, molecular weight of PEG, amount of added reactants and temperature) on the dechlorination behavior was studied. Promising performances were reached, allowing about 50% of dechlorination under the best experimental conditions, together time and energy saving compared to conventional heating systems. Moreover, an interesting dechlorination degree (up to 32%) was achieved for siloxane transformer oil when MW irradiation was employed as the unique driving force. To the best of our knowledge, this is the first time in which MW irradiation is tested as the single driving force for the dechlorination of these two types of PCB-contaminated oils. PMID:27281539

  1. Synthesis of solar active nanocrystalline ferrite, MFe 2O 4 (M: Ca, Zn, Mg) photocatalyst by microwave irradiation

    NASA Astrophysics Data System (ADS)

    Dom, Rekha; Subasri, R.; Radha, K.; Borse, Pramod H.

    2011-03-01

    For the first time, nanocrystalline photocatalysts of spinel MgFe2O4, ZnFe2O4 and orthorhombic CaFe2O4 oxides were synthesized (at low temperature ˜973 K) by microwave sintering, in one sixtieth of the time required to that of the conventional method. A significantly improved crystallinity was obtained for the samples irradiated for longer duration of time (˜10-100 min). The theoretically computed electronic structure of the MFe2O4 (M: Ca, Zn, Mg) systems was respectively correlated with the experimental results obtained from their structural and photocatalytic characterization. The photocatalytic performance was found to be affected by surface area and crystallinity of the photocatalyst. The density functional theory (DFT) calculations of MFe2O4 lattices revealed that M-ion controllably affects the density of sates of the Fe-d orbitals near the Fermi level. Consequently they play an important role in determining the band-energetics and thus the visible light photocatalytic activity for methylene blue degradation.

  2. Rapid preparation of expanded graphite by microwave irradiation for the extraction of triazine herbicides in milk samples.

    PubMed

    Zhang, Fengshuang; Zhao, Qi; Yan, Xu; Li, Huiyu; Zhang, Ping; Wang, Long; Zhou, Tianyu; Li, Yi; Ding, Lan

    2016-04-15

    In this study, we proposed a rapid and efficient method for the preparation of the expanded graphite (EG). The exfoliation process was accelerated by microwave irradiation, and the preparation time was greatly shortened. The obtained EG was worm-like in shape and exhibits well exfoliated structure. It was successfully applied as solid-phase extraction (SPE) adsorbent to extract and clean up the triazine herbicides in milk, followed by liquid chromatography tandem mass spectrometry (LC-MS) analysis. The parameters affecting the performance of extraction and LC-MS analysis were evaluated. Under the optimal conditions, the detection limits of triazines are in the range of 0.03-0.12 ng mL(-1). At the spiked level (0.4 ng mL(-1)), the recoveries of triazines are in the range of 82.5±2.5% to 97.5±7.5%. The proposed method was successfully applied to determine six triazines in six milk samples. PMID:26617038

  3. Regioselective synthesis and ab initio calculations of fused heterocycles thermally and under microwave irradiation

    NASA Astrophysics Data System (ADS)

    Salem, Mostafa E.; Ahmed, Ashour A.; Shaaban, Mohamed R.; Shibl, Mohamed F.; Farag, Ahmad M.

    2015-09-01

    Pyrazolo[1,5-a]pyrimidine, triazolo[1,5-a]pyrimidine, and pyrimido[1,2-a]benzimidazole, pyrido[1,2-a]benzimidazole ring systems incorporating phenylsulfonyl moiety were synthesized via the reaction of 3-(N,N-dimethylamino)-1-(thiophen-2-yl)-2-(phenylsulfonyl)prop-2-en-1-one derivatives with the appropriate aminoazoles as 1,3-binucleophiles and 1H-benzimidazol-2-ylacetonitrile using conventional methods as well as microwave irradiation. The regioselectivity of the cyclocondensation reactions was confirmed both experimentally by alternative synthesis of reaction products and theoretically using ab initio quantum chemical calculations namely the Density Functional Theory (DFT). The theoretical work was carried out using the Becke, three parameter, Lee-Yang-Parr hybrid functional (B3LYP) combined with the 6-311++G(d,p) basis set. It was found that the final cyclocondensation reaction product depends mainly on the initial addition to the activated double bond by the nitrogen atom of the 1,3-binucleophiles that has the higher electron density.

  4. Microwave irradiation for shortening the processing time of samples of flagellated bacteria for scanning electron microscopy.

    PubMed

    Hernández-Chavarría, Francisco

    2004-01-01

    Microwave irradiation (MWI) has been applied to the development of rapid methods to process biological samples for scanning electron microscopy (SEM). In this paper we propose two simple and quick techniques for processing bacteria (Proteus mirabilis and Vibrio mimicus) for SEM using MWI. In the simplest methodology, the bacteria were placed on a cover-glass, air-dried, and submitted to conductivity stain. The reagent used for the conductivity stain was the mordant of a light microscopy staining method (10 ml of 5% carbolic acid solution, 2 g of tannic acid, and 10 ml of saturated aluminum sulfate 12-H2O). In the second method the samples were double fixed (glutaraldehyde and then osmium), submitted to conductivity stain, dehydrated through a series of ethanol solutions of increasing concentration, treated with hexamethyldisilazine (HMDS), and dried at 35 degrees C for 5 minutes. In both methods the steps from fixation to treatment with HMDS were done under MWI for 2 minutes in an ice-water bath, in order to dissipate the heat generated by the MWI. Although both techniques preserve bacterial morphology adequately, the latter, technique showed the best preservation, including the appearance of flagella, and that process was completed in less than 2 hours at temperatures of MWI between 4 to 5 degrees C. PMID:17061527

  5. An approach of ionic liquids/lithium salts based microwave irradiation pretreatment followed by ultrasound-microwave synergistic extraction for two coumarins preparation from Cortex fraxini.

    PubMed

    Liu, Zaizhi; Gu, Huiyan; Yang, Lei

    2015-10-23

    Ionic liquids/lithium salts solvent system was successfully introduced into the separation technique for the preparation of two coumarins (aesculin and aesculetin) from Cortex fraxini. Ionic liquids/lithium salts based microwave irradiation pretreatment followed by ultrasound-microwave synergy extraction (ILSMP-UMSE) procedure was developed and optimized for the sufficient extraction of these two analytes. Several variables which can potentially influence the extraction yields, including pretreatment time and temperature, [C4mim]Br concentration, LiAc content, ultrasound-microwave synergy extraction (UMSE) time, liquid-solid ratio, and UMSE power were optimized by Plackett-Burman design. Among seven variables, UMSE time, liquid-solid ratio, and UMSE power were the statistically significant variables and these three factors were further optimized by Box-Behnken design to predict optimal extraction conditions and find out operability ranges with maximum extraction yields. Under optimum operating conditions, ILSMP-UMSE showed higher extraction yields of two target compounds than those obtained by reference extraction solvents. Method validation studies also evidenced that ILSMP-UMSE is credible for the preparation of two coumarins from Cortex fraxini. This study is indicative of the proposed procedure that has huge application prospects for the preparation of natural products from plant materials. PMID:26411478

  6. Zero-resistance states in Hall bars at low microwave frequency irradiation

    SciTech Connect

    Iñarrea, J.

    2013-12-04

    We report on theoretical studies of recently discovered radiation-induced resistance oscillations and zero resistance states in Hall bars when the irradiation frequency is very low. In this situation the photon energy is much smaller than the spacing between the Landau levels and therefore interlevel transitions are excluded. We apply the radiation-driven electron orbit model concluding that the resistance suppression is a manifestation of “long-wavelength” resistance oscillations where only one complete oscillation is observed.

  7. Estimation of Radiofrequency Power Leakage from Microwave Ovens for Dosimetric Assessment at Nonionizing Radiation Exposure Levels

    PubMed Central

    Lopez-Iturri, Peio; de Miguel-Bilbao, Silvia; Aguirre, Erik; Azpilicueta, Leire; Falcone, Francisco; Ramos, Victoria

    2015-01-01

    The electromagnetic field leakage levels of nonionizing radiation from a microwave oven have been estimated within a complex indoor scenario. By employing a hybrid simulation technique, based on coupling full wave simulation with an in-house developed deterministic 3D ray launching code, estimations of the observed electric field values can be obtained for the complete indoor scenario. The microwave oven can be modeled as a time- and frequency-dependent radiating source, in which leakage, basically from the microwave oven door, is propagated along the complete indoor scenario interacting with all of the elements present in it. This method can be of aid in order to assess the impact of such devices on expected exposure levels, allowing adequate minimization strategies such as optimal location to be applied. PMID:25705676

  8. Estimation of radiofrequency power leakage from microwave ovens for dosimetric assessment at nonionizing radiation exposure levels.

    PubMed

    Lopez-Iturri, Peio; de Miguel-Bilbao, Silvia; Aguirre, Erik; Azpilicueta, Leire; Falcone, Francisco; Ramos, Victoria

    2015-01-01

    The electromagnetic field leakage levels of nonionizing radiation from a microwave oven have been estimated within a complex indoor scenario. By employing a hybrid simulation technique, based on coupling full wave simulation with an in-house developed deterministic 3D ray launching code, estimations of the observed electric field values can be obtained for the complete indoor scenario. The microwave oven can be modeled as a time- and frequency-dependent radiating source, in which leakage, basically from the microwave oven door, is propagated along the complete indoor scenario interacting with all of the elements present in it. This method can be of aid in order to assess the impact of such devices on expected exposure levels, allowing adequate minimization strategies such as optimal location to be applied. PMID:25705676

  9. Target detection using microwave irradiances from natural sources: A passive, local and global surveillance system

    NASA Astrophysics Data System (ADS)

    Stacey, J. M.

    1984-11-01

    Detection of metal objects on or near the Earth's surface was investigated using existing, passive, microwave sensors operating from Earth orbit. The range equations are derived from basic microwave principles and theories and the expressions are given explicitly to estimate the signal to noise ratio for detecting metal targets operating as bistatic scatterers. Actual measurements are made on a range of metal objects observed from orbit using existing passive microwave receiving systems. The details of the measurements and the results are tabulated and discussed. The advantages of a passive microwave sensor as it is applied to surveillance of metal objects as viewed from aerial platforms or from orbit, are examined.

  10. Photolysis of low concentration H2S under UV/VUV irradiation emitted from microwave discharge electrodeless lamps.

    PubMed

    Xia, Lan-Yan; Gu, Ding-Hong; Tan, Jing; Dong, Wen-Bo; Hou, Hui-Qi

    2008-04-01

    The photolysis of simulating low concentration of hydrogen sulfide malodorous gas was studied under UV irradiation emitted by self-made microwave discharge electrodeless lamps (i.e. microwave UV electrodeless mercury lamp (185/253.7 nm) and iodine lamp (178.3/180.1/183/184.4/187.6/206.2 nm)). Experiments results showed that the removal efficiency (eta H2S) of hydrogen sulfide was decreased with increasing initial H2S concentration and increased slightly with gas residence time; H2S removal efficiency was decreased dramatically with enlarged pipe diameter. Under the experimental conditions with pipe diameter of 36 mm, gas flow rate of 0.42 standard l s(-1), eta H2S was 52% with initial H2S concentration of 19.5 mg m(-3) by microwave mercury lamp, the absolute removal amount (ARA) was 4.30 microg s(-1), and energy yield (EY) was 77.3 mg kW h(-1); eta H2S was 56% with initial H2S concentration of 18.9 mg m(-3) by microwave iodine lamp, the ARA was 4.48 microg s(-1), and the EY was 80.5mg kW h(-1). The main photolysis product was confirmed to be SO4(2-) with IC. PMID:18334265

  11. Development of a Backbone Cyclic Peptide Library as Potential Antiparasitic Therapeutics Using Microwave Irradiation.

    PubMed

    Qvit, Nir; Kornfeld, Opher S

    2016-01-01

    Protein-protein interactions (PPIs) are intimately involved in almost all biological processes and are linked to many human diseases. Therefore, there is a major effort to target PPIs in basic research and in the pharmaceutical industry. Protein-protein interfaces are usually large, flat, and often lack pockets, complicating the discovery of small molecules that target such sites. Alternative targeting approaches using antibodies have limitations due to poor oral bioavailability, low cell-permeability, and production inefficiency. Using peptides to target PPI interfaces has several advantages. Peptides have higher conformational flexibility, increased selectivity, and are generally inexpensive. However, peptides have their own limitations including poor stability and inefficiency crossing cell membranes. To overcome such limitations, peptide cyclization can be performed. Cyclization has been demonstrated to improve peptide selectivity, metabolic stability, and bioavailability. However, predicting the bioactive conformation of a cyclic peptide is not trivial. To overcome this challenge, one attractive approach it to screen a focused library to screen in which all backbone cyclic peptides have the same primary sequence, but differ in parameters that influence their conformation, such as ring size and position. We describe a detailed protocol for synthesizing a library of backbone cyclic peptides targeting specific parasite PPIs. Using a rational design approach, we developed peptides derived from the scaffold protein Leishmania receptor for activated C-kinase (LACK). We hypothesized that sequences in LACK that are conserved in parasites, but not in the mammalian host homolog, may represent interaction sites for proteins that are critical for the parasites' viability. The cyclic peptides were synthesized using microwave irradiation to reduce reaction times and increase efficiency. Developing a library of backbone cyclic peptides with different ring sizes facilitates a

  12. Ultrafast in vivo microwave irradiation for enhanced metabolic stability of brain biopsy samples during HRMAS NMR analysis.

    PubMed

    Detour, J; Elbayed, K; Piotto, M; Moussallieh, F M; Nehlig, A; Namer, I J

    2011-09-30

    High resolution magic-angle spinning (HRMAS) NMR spectroscopy is a well established technique for ex vivo metabolite investigations but experimental factors such as ischemic delay or mechanical stress due to continuous spinning deserve further investigations. Cortical brain samples from rats that underwent ultrafast in vivo microwave irradiation (MWp group) were compared to similar samples that underwent standard nitrogen freezing with and without exposure to domestic microwaves (FN and FN+MWd groups). One dimensional (1)H HRMAS NMR spectra were acquired and 16 metabolites of interest were quantified. Within each group 3 samples underwent long lasting acquisition (up to 15 h). Statistically significant differences in metabolite concentrations were observed between groups for metabolites associated to post mortem biochemical changes and/or anaerobic glycolysis including several neurotransmitters. Spectral assessment over time showed a drastic reduction of biochemical variations in both MW groups. Only 2/16 metabolites exhibited significant signal variations after 15 h of continuous spinning and acquisition in the MWp group. This number increased to 10 in the FN group. We confirmed limited anaerobic metabolism and post mortem degradation after ultra fast in vivo MW irradiation. Furthermore, spectra obtained after MWp and MWd irradiation exhibited an extremely stable spectral pattern over extended periods of continuous acquisition. PMID:21803072

  13. Influences of doping Cr/Fe/Ta on the performance of Ni/CeO2 catalyst under microwave irradiation in dry reforming of CH4

    NASA Astrophysics Data System (ADS)

    Odedairo, Taiwo; Ma, Jun; Chen, Jiuling; Wang, Shaobin; Zhu, Zhonghua

    2016-01-01

    The structure of Ni/CeO2 catalyst with doping of Cr, Fe and Ta was investigated with XRD, N2 physisorption, XPS and HRTEM and the catalytic activity of the catalysts under microwave irradiation in dry reforming of methane was tested in a microwave reactor. The results show that the introduction of Cr and Ta to Ni/CeO2 can enhance the interaction between Ni and the support/promoter and inhibit the enlargement of NiO particles during the synthesis. The CH4 conversions in dry reforming on the catalysts follow the order: Ni/CeO2<2Fe-Ni<2Ta-Ni<2Cr-Ni. The superior performance of 2Ta-Ni and 2Cr-Ni may be attributed to the locally-heated Ni particles caused by the strong microwave absorption of the in-situ grown graphene attached on them under microwave irradiation.

  14. Dynamic microstructures and fractal characterization of cell wall disruption for microwave irradiation-assisted lipid extraction from wet microalgae.

    PubMed

    Cheng, Jun; Sun, Jing; Huang, Yun; Feng, Jia; Zhou, Junhu; Cen, Kefa

    2013-12-01

    To extract lipids from wet microalgae through cell disruption, the effects of microwave treatment on the dynamic cell wall microstructures were investigated. The fractal dimension of raw, untreated microalgal cells was 1.46. The disruption level of microalgal cell walls was enhanced when microwave treatment temperature increased from 80 to 120°C, resulting in an increase in microalgal cell fractal dimension from 1.61 to 1.91. The cell wall thickness and pore diameters in cell walls increased from 0.11 to 0.59 μm and from 0.005 to 0.18 μm, respectively, when microwave treatment time increased from 0 to 20 min. The outer pectin layers of cell walls gradually detached and the porosity of inner cellulose layers increased when microwave treatment time increased to 26 min. The initial point of disruption appeared at the maximum curvature (approximately 1.01×10(7) m(-1)) of cell walls. Numbers of short-chain and saturated lipids increased because of microwave electromagnetic effect. PMID:24152788

  15. PROCESS INTENSIFICATION: OXIDATION OF BENZYL ALCOHOL USING A CONTINUOUS ISOTHERMAL REACTOR UNDER MICROWAVE IRRADIATION

    EPA Science Inventory

    In the past two decades, several investigations have been carried out using microwave radiation for performing chemical transformations. These transformations have been largely performed in conventional batch reactors with limited mixing and heat transfer capabilities. The reacti...

  16. Facile synthesis of lead iodide nanostructures by microwave irradiation technique and their structural, morphological, photoluminescence and dielectric studies

    NASA Astrophysics Data System (ADS)

    Shkir, Mohd.; Yahia, I. S.; AlFaify, S.; Abutalib, M. M.; Muhammad, Shabbir

    2016-04-01

    Lead iodide (PbI2) nanostructures have been synthesized by co-precipitation, hydrothermal and rapidly by microwave irradiation techniques. SEM analysis indicated the formation of well aligned nanocrystals and nanorods of average diameter between 100 nm and 400 nm. The powder X-ray diffraction and FT-Raman spectroscopic analysis confirms the formation of a 2H-PbI2 polytypic predominantly. These studies also show that there is no extra phase due to impurity in the synthesized nanostructures. The optical energy band gap of nanostructures prepared by co-precipitation, hydrothermal and microwave irradiation techniques were found to be 2.283, 2.493, 2.542 eV and 2.331. 2.350, 2.375 eV calculated from UV-Vis absorption and diffuse reflectance data, respectively, which shows a clear blue shift in the wavelength due to confinement effect. Photoluminescence spectrum was recorded at different excitation wavelengths and shows clear blue shift in the emission peak which is due to the recombination of free excitons with band to band type transition and also may be due to confinement effect. Further the dielectric studies have been performed and a good enhancement in the dielectric constant has been observed due to small size of the fabricated nanostructures in comparison to bulk material.

  17. Morphological control and evolution of octahedral and truncated trisoctahedral Pt-Au alloy nanocrystals under microwave irradiation

    NASA Astrophysics Data System (ADS)

    Dai, Lei; Zhao, Yanxi; Chi, Quan; Liu, Hanfan; Li, Jinlin; Huang, Tao

    2014-08-01

    Uniform and well-defined truncated trisoctahedral and octahedral Pt-Au alloy nanocrystals were fabricated by co-reducing H2PtCl6-HAuCl4 with tetraethylene glycol (TEG) under microwave irradiation for only 140 s. Iodide ions were critical to the morphological control and evolution of Pt-Au alloy nanostructures. The as-prepared Pt-Au alloy nanocrystals exhibited efficient electrocatalytic activities.Uniform and well-defined truncated trisoctahedral and octahedral Pt-Au alloy nanocrystals were fabricated by co-reducing H2PtCl6-HAuCl4 with tetraethylene glycol (TEG) under microwave irradiation for only 140 s. Iodide ions were critical to the morphological control and evolution of Pt-Au alloy nanostructures. The as-prepared Pt-Au alloy nanocrystals exhibited efficient electrocatalytic activities. Electronic supplementary information (ESI) available: Experimental details; SEM, TEM and HAADF-STEM images, UV-vis absorbance spectra, XRD. See DOI: 10.1039/c4nr01864h

  18. Effects of dehulling, steam-cooking and microwave-irradiation on digestive value of white lupin (Lupinus albus) seed meal for rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar).

    PubMed

    Saez, Patricio; Borquez, Aliro; Dantagnan, Patricio; Hernández, Adrián

    2015-01-01

    A digestibility trial was conducted to assess the effect of dehulling, steam-cooking and microwave-irradiation on the apparent digestibility of nutrients in white lupin (Lupinus albus) seed meal when fed to rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar). Six ingredients, whole lupin seed meal (LSM), dehulled LSM, dehulled LSM steam-cooked for 15 or 45 min (SC15 and SC45, respectively) and LSM microwave-irradiated at 375 or 750 W (MW375 and MW750, respectively), were evaluated for digestibility of dry matter, crude protein (CP), lipids, nitrogen-free extractives (NFE) and gross energy (GE). The diet-substitution approach was used (70% reference diet + 30% test ingredient). Faeces from each tank were collected using a settlement column. Dehulled LSM showed higher levels of proximate components (except for NFE and crude fibre), GE and phosphorus in comparison to whole LSM. Furthermore, SC15, SC45, MW375 and MW750 showed slight variations of chemical composition in comparison to dehulled LSM. Results from the digestibility trial indicated that dehulled LSM, SC15, SC45 and MW375 are suitable processing methods for the improvement of nutrients' apparent digestibility coefficient (ADC) in whole LSM. MW750 showed a lower ADC of nutrients (except for CP and lipids for rainbow trout) in comparison with MW350 for rainbow trout and Atlantic salmon, suggesting a heat damage of the ingredient when microwave-irradiation exceeded 350 W. PMID:25708530

  19. Effect of different fat level on microwave cooking properties of goat meat patties.

    PubMed

    Das, Arun K; Rajkumar, V

    2013-12-01

    The study was carried out to evaluate the effect of various fat levels on the cooking and sensory properties of goat meat patties cooked by microwave energy. Goat meat patties were prepared with refined vegetable oil to get fat level of 5, 10, 15 and 20%. Each patty was cooked in a microwave oven with full power (700 W) operating at 2450 MHz to an internal temperature of 75-80 °C. pH value of raw patties with 5% fat level were lower compared to patties with 10, 15 and 20% fat level. Fat level did not affect emulsion stability of batter but it decreased as fat level increased. Microwave cooking time decreased as fat levels increased. With an increase in fat contents, protein and moisture in raw patties decreased and in cooked meat patties with 5% fat had higher protein and moisture content than those with more fat. Patties with 5% level showed lower cooking loss than other fat level. Water activity of patties was affected by fat level and patties with 15 and 20% fat had lower water activity than patties with 5 and 10% fat. As fat level increased, shear force value decreased indicating soft texture. Subjective colour evaluation indicated that 5% patties were darker and redder than patties with more fat. Sensory analysis revealed that goat meat patties with 5 and 10% fat had less flavour and juicer than patties with 15 and 20% fat. Goat meat patties with 20% fat were the juiciest. Tenderness and oiliness increased significantly with an increase in fat level. Patties with 15% fat were rated higher overall palatability than others. PMID:24426036

  20. The Quality Characteristics of Salted Ground Pork Patties Containing Various Fat Levels by Microwave Cooking.

    PubMed

    Jeong, Jong Youn; Lim, Seung Taek; Kim, Cheon Jei

    2016-01-01

    This study was carried out to evaluate the effects of fat level on the microwave cooking properties of ground pork patties with NaCl (1.5%). Ground pork patties were processed from pork hams to achieve fat levels of 10%, 15%, 20%, and 25%, respectively. Each patty was cooked from a thawed state to 75℃ in a microwave oven at full power (700 W). After microwave cooking, protein content, moisture content, fat retention, and shear force values in patties decreased as fat level increased from 10 to 25%. As fat level increased, cooking time decreased but total cooking loss and drip loss were increased, whereas slight differences in diameter reduction and thickness of patties were observed. In raw patties, 10% fat patties had lower L* values and higher a* values compared to patties with more fat, but these differences were reduced when patties were cooked. Patties with 10% fat showed a more pink color on the surface and interior than patties with a higher fat content but more air pockets were noted in higher-fat patties. Higher-fat patties were more tender, juicy, and oily than lower-fat patties. PMID:27621696

  1. The Quality Characteristics of Salted Ground Pork Patties Containing Various Fat Levels by Microwave Cooking

    PubMed Central

    Jeong, Jong Youn; Lim, Seung Taek; Kim, Cheon Jei

    2016-01-01

    This study was carried out to evaluate the effects of fat level on the microwave cooking properties of ground pork patties with NaCl (1.5%). Ground pork patties were processed from pork hams to achieve fat levels of 10%, 15%, 20%, and 25%, respectively. Each patty was cooked from a thawed state to 75℃ in a microwave oven at full power (700 W). After microwave cooking, protein content, moisture content, fat retention, and shear force values in patties decreased as fat level increased from 10 to 25%. As fat level increased, cooking time decreased but total cooking loss and drip loss were increased, whereas slight differences in diameter reduction and thickness of patties were observed. In raw patties, 10% fat patties had lower L* values and higher a* values compared to patties with more fat, but these differences were reduced when patties were cooked. Patties with 10% fat showed a more pink color on the surface and interior than patties with a higher fat content but more air pockets were noted in higher-fat patties. Higher-fat patties were more tender, juicy, and oily than lower-fat patties. PMID:27621696

  2. Microwave power transmission system wherein level of transmitted power is controlled by reflections from receiver

    NASA Technical Reports Server (NTRS)

    Robinson, W. J., Jr. (Inventor)

    1974-01-01

    A microwave, wireless, power transmission system is described in which the transmitted power level is adjusted to correspond with power required at a remote receiving station. Deviations in power load produce an antenna impedance mismatch causing variations in energy reflected by the power receiving antenna employed by the receiving station. The variations in reflected energy are sensed by a receiving antenna at the transmitting station and used to control the output power of a power transmitter.

  3. Separation of ZnO from the Stainless Steelmaking Dust and Graphite Mixture by Microwave Irradiation

    NASA Astrophysics Data System (ADS)

    Zhou, Yun; Wu, Liushun; Wang, Jue; Wang, Haichuan; Dong, Yuanchi

    2015-04-01

    In this study, microwave was used to treat stainless steelmaking dust containing zinc oxide. The effects of heating time, carbon content and zinc oxide content on the removal efficiency of zinc oxide and the reduction efficiency of iron oxide were investigated. Experimental results show that, for the sample with 16% (mass percent, the same below) graphite heated for 10 minutes by 10 kW power microwave, the removal efficiency of zinc oxide is between 80% and 90% and the metallization ratio of iron oxide is between 40% and 60%; Initial zinc oxide content has a slight effect on the removal efficiency of zinc oxide. The results indicate microwave treatment is one of the feasible ways to process metallurgical solid waste containing the metal with low boiling point.

  4. Rapid and Efficient Functionalized Ionic Liquid-Catalyzed Aldol Condensation Reactions Associated with Microwave Irradiation

    PubMed Central

    Wang, Chang; Liu, Jing; Leng, Wenguang; Gao, Yanan

    2014-01-01

    Five quaternary ammonium ionic liquid (IL) and two tetrabutylphosphonium ILs were prepared and characterized. An environmentally benign and convenient functionalized ionic liquid catalytic system was thus explored in the aldol condensation reactions of aromatic aldehydes with acetone. The aldol reactions proceeded more efficiently through microwave-assisted heating than through conventional thermal heating. The yield of products obtained under microwave heating for 30 min was approximately 90%, and the ILs can be recovered and reused at least five times without apparent loss of activity. In addition, this catalytic system can be successfully extended to the Henry reactions. PMID:24445262

  5. Synergetic pretreatment of sewage sludge by microwave irradiation in presence of H2O2 for enhanced anaerobic digestion.

    PubMed

    Eskicioglu, Cigdem; Prorot, Audrey; Marin, Juan; Droste, Ronald L; Kennedy, Kevin J

    2008-11-01

    A microwave-enhanced advanced hydrogen peroxide oxidation process (MW/H(2)O(2)-AOP) was studied in order to investigate the synergetic effects of MW irradiation on H(2)O(2) treated waste activated sludges (WAS) in terms of mineralization (permanent stabilization), sludge disintegration/solubilization, and subsequent anaerobic biodegradation as well as dewaterability after digestion. Thickened WAS sample pretreated with 1gH(2)O(2)/g total solids (TS) lost 11-34% of its TS, total chemical oxygen demand (COD) and total biopolymers (humic acids, proteins and sugars) via advanced oxidation. In a temperature range of 60-120 degrees C, elevated MW temperatures (>80 degrees C) further increased the decomposition of H(2)O(2) into OH* radicals and enhanced both oxidation of COD and solubilization of particulate COD (>0.45 micron) of WAS indicating that a synergetic effect was observed when both H(2)O(2) and MW treatments were combined. However, at all temperatures tested, MW/H(2)O(2) treated samples had lower first-order mesophilic (33+/-2 degrees C) biodegradation rate constants and ultimate (after 32 days of digestion) methane yields (mL per gram sample) compared to control and MW irradiated WAS samples, indicating that synergistically (MW/H(2)O(2)-AOP) generated soluble organics were slower to biodegrade or more refractory than those generated during MW irradiation. PMID:18783812

  6. ‘Greener’ Chemical Syntheses Using Mechanochemical Mixing or Microwave and Ultrasound Irradiation

    EPA Science Inventory

    Various emerging ‘greener’ strategic pathways researched primarily in the author’s own laboratory are summarized. They include solvent-free mechanochemical methods and microwave (MW) exposure of neat reactants (undiluted) catalyzed by the surfaces of less-expensive and recyclabl...

  7. Rapid conversion of sorbitol to isosorbide in hydrophobic ionic liquids under microwave irradiation.

    PubMed

    Kamimura, Akio; Murata, Kengo; Tanaka, Yoshiki; Okagawa, Tomoki; Matsumoto, Hiroshi; Kaiso, Kouji; Yoshimoto, Makoto

    2014-12-01

    Sorbitol was effectively converted to isosorbide by treatment with [TMPA][NTf2 ] in the presence of catalytic amounts of TsOH under microwave heating at 180 °C. The reaction completed within 10 min and isosorbide was isolated to about 60%. Ionic liquids were readily recovered by an extraction treatment and reused several times. PMID:25223397

  8. Assessment of cochlear damage after microwave irradiation. Final report, 30 September 1985-17 February 1988

    SciTech Connect

    Bohne, B.A.; Gruner, M.M.; Bassen, H.I.

    1988-02-26

    The objective of this project was to determine whether or not excessive exposure to microwaves results in permanent damage to the inner ear. A group of 15 chinchillas was exposed for one hour to pulsed microwaves (1250 MHz) of 20 usec duration and 0.1-Hz repetition rate and an average power of 1 Watt. The specific absorption rate of various measurement sites in the head ranged from 2-8 Wkg. The exposures were done at the WRAIR Microwave Laboratory, Washington, D.C. Seven animals were sham-exposed for one hour using the same apparatus and sedation. For the sham exposures, the microwave equipment was powered but no radiation was delivered. The cochleas from 20 control chinchillas of the same age range as the animals in the study were available for comparison purposes. The controls had spent their entire lives in sound-treated animal quarters at Washington University in St. Louis, MO. The cochleas from all animals were processed for histological evaluation as plastic-embedded flat preparations. Some animals were processed less than 24 hour after their exposures; the rest were processed after a month or more of recovery. In each cochlea, the following quantitative data were obtained: the extent and pattern of degeneration in the sensory-cell populations; the number of missing pillar cells; the extent and location of degeneration of the stria vascularis and of the myelinated nerve fibers in the osseous spiral lamina.

  9. MICROWAVE IRRADIATION IN BENIGN SYNTHESIS OF ORGANIC MOLECULES, NOBLE NANOMETALS AND NANOCOMPOSITES

    EPA Science Inventory

    A brief historic account of reactions involving microwave (MW) exposure of neat reactants or catalyzed by mineral support surfaces, such as alumina, silica, clay, or their ‘doped’ versions, for the rapid one-pot assembly of heterocyclic compounds [1] from in situ generated reacti...

  10. MICROWAVE IRRADIATION IN BENIGN SYNTHESIS OF HETEROCYCLES, NOBLE NANOMETALS AND NANOCOMPOSITES

    EPA Science Inventory

    A brief historic account of reactions involving microwave (MW) exposure of neat reactants or catalyzed by mineral support surfaces, such as alumina, silica, clay, or their ‘doped’ versions, for the rapid one-pot assembly of heterocyclic compounds [1] from in situ generated reacti...

  11. GREENER ORGANIC SYNTHESES UNDER NON-TRADITIONAL CONDITIONS USING MICROWAVE AND ULTRASOUND IRRADIATION AND MECHANOCHEMICAL MIXING

    EPA Science Inventory

    Solvent-free mechanochemical methods that involve the use of hypervalent iodine reagents at room temperature are described for the synthesis of heterocyclic entities and conversion of ketones into -keto sulfones in high yields. A solvent-free approach that involves microwave (MW...

  12. SOLVENT-FREE REDUCTION OF AROMATIC NITRO COMPOUNDS WITH ALUMINA-SUPPORTED HYDRAZINE UNDER MICROWAVE IRRADIATION

    EPA Science Inventory

    In a solvent-free microwave-expedited process, aromatic nitro compounds are readily reduced to the corresponding amino compounds in good yield with hydrazine hydrate supported on alumina in presence of FeCl3, 6H2), Fe(III) oxide hydroxide or Fe(III) oxides.

  13. Expeditious synthesis of noble metal nanoparticles using Vitamin B12 under microwave irradiation

    EPA Science Inventory

    A greener synthesis protocol for noble nanometals is developed using vitamin B12 as a reducing and capping agent in conjunction with the use of microwaves. Successful assembly of nanoparticles or microparticles with varied shapes and sizes have been demonstrated. The synthesized ...

  14. BULK SYNTHESIS OF SILVER NANORODS IN POLY(ETHYLENE GLYCOL) USING MICROWAVE IRRADIATION

    EPA Science Inventory

    Microwave-assisted (MW), surfactantless, greener approach to bulk synthesis of silver nanorods employing poly (ethylene glycol) (PEG) is described. An aqueous solution of silver nitrate (AgNO-3,- 0.1 M, 4 mL) and 4 mL of PEG (molecular weight 300) were mixed at room temperature t...

  15. Soil microbial biomass carbon measurement using microwave irradiation: effects of soil water content, texture and temperature on microbial cell kill and C release

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fumigation-based methods of soil microbial biomass carbon (C) have been replaced in many labs by microwave (MW) irradiation-based methods to reduce hazardous chemical use. Sine the introduction of the MW method concerns have been raised about the use of water filled porosity (WFP) for water content...

  16. EFFECT OF POLY (ETHYLENE GLYCOL) ON THE FORMATION OF NANOSTRUCTURES: A FACILE SUSTAINABLE APPROACH FOR THE SYNTHESIS OF SILVER NANORODS USING MICROWAVE IRRADIATION

    EPA Science Inventory

    Bulk synthesis of silver nanorods employing poly (ethylene glycol) (PEG) under microwave irradiation is reported. The formation of nanorods or particulate morphology is dependent on the PEG concentration. This greener method uses no surfactants or reducing agents and employs a b...

  17. Total synthesis of protosappanin A and its derivatives via palladium catalyzed ortho C-H activation/C-C cyclization under microwave irradiation.

    PubMed

    Liu, Jiaqi; Zhou, Xuan; Wang, Chenglong; Fu, Wanyong; Chu, Wenyi; Sun, Zhizhong

    2016-04-14

    A total synthesis method for protosappanin A, which is a complex natural product with many biological activities, was developed with 6 linear steps. Dibenzo[b,d]oxepinones as the key intermediates of the synthetic route were prepared by a palladium-catalyzed ortho C-H activation/C-C cyclization under microwave irradiation. 25 derivatives of protosappanin A were obtained. PMID:26997503

  18. PHENOLIC CONTENT AND ANTIOXIDANT ACTIVITY OF SUPERCRITICAL CARBON DIOXIDE-TREATED AND AIR-CLASSIFIED OAT BRAN CONCENTRATE MICROWAVE-IRRADIATED IN WATER OR ETHANOL AT VARYING TEMPERATURES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oat bran concentrate (OBC) was defatted with supercritical carbon dioxide (SCD), then microwave-irradiated at 50, 100 or 150 deg C for 10 min in water, 50% or 100% ethanol, and extract pH, soluble solids, phenolic content and antioxidant activity were analyzed. OBC was air-classified into five frac...

  19. Elevation of serum 25-hydroxycalciferol levels in androgen-treated and ultraviolet-irradiated rats.

    PubMed

    Ohata, M; Sakagami, Y; Fujita, T

    1977-10-01

    Administration of 4-8 mg testosterone propionate significantly raised 25-hydroxycalciferol levels in the ultraviolet irradiated rats compared to the ultraviolet irradiated controls, but failed to influence serum 25-hydroxycalciferol levels in the non-irradiated animals. Estradiol benzoate and progesterone did not influence serum 25-hydroxycalciferol levels regardless of the ultraviolet irradiation. These findings implicate that testosterone enhances vitamin D biosynthesis induced by ultraviolet irradiation in rats, in accordance with the clinical observation that males often show higher levels of serum 25-hydroxycalciferol than females. PMID:303993

  20. Proton irradiation effects on advanced digital and microwave III-V components

    SciTech Connect

    Hash, G.L.; Schwank, J.R.; Shaneyfelt, M.R.; Sandoval, C.E.; Connors, M.P.; Sheridan, T.J.; Sexton, F.W.; Slayton, E.M.; Heise, J.A.; Foster, C.

    1994-09-01

    A wide range of advanced III-V components suitable for use in high-speed satellite communication systems were evaluated for displacement damage and single-event effects in high-energy, high-fluence proton environments. Transistors and integrated circuits (both digital and MMIC) were irradiated with protons at energies from 41 to 197 MeV and at fluences from 10{sup 10} to 2 {times} 10{sup 14} protons/cm{sup 2}. Large soft-error rates were measured for digital GaAs MESFET (3 {times} 10{sup {minus}5} errors/bit-day) and heterojunction bipolar circuits (10{sup {minus}5} errors/bit-day). No transient signals were detected from MMIC circuits. The largest degradation in transistor response caused by displacement damage was observed for 1.0-{mu}m depletion- and enhancement-mode MESFET transistors. Shorter gate length MESFET transistors and HEMT transistors exhibited less displacement-induced damage. These results show that memory-intensive GaAs digital circuits may result in significant system degradation due to single-event upset in natural and man-made space environments. However, displacement damage effects should not be a limiting factor for fluence levels up to 10{sup 14} protons/cm{sup 2} [equivalent to total doses in excess of 10 Mrad(GaAs)].

  1. Rapid photocatalytic destruction of pentachlorophenol in F-Si-comodified TiO(2) suspensions under microwave irradiation.

    PubMed

    Yang, Shaogui; Fu, Hongbo; Sun, Cheng; Gao, Zhanqi

    2009-01-30

    A novel photocatalysis material, F-Si-comodified TiO(2) (FST) powder, was synthesized by ultrasound-assisted hydrolysis. The prepared material was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-visible absorption spectroscopy, respectively. XRD analysis indicated that the phase of FST was pure anatase and Si atoms suppressed the growth of titania crystalline, XPS spectra showed that FST was composed of Ti, O, Si and F element, the band gap energy of FST calculated according to the spectrum of UV-vis absorption was 3.26 eV. The electron spin resonance (ESR) spin-trapping technique using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as the spin-trap reagent has been applied to detect free radical intermediates generated from FST. ESR results showed the concentration of the active species (OH) on FST is higher than those on F-doping TiO(2) (FT), Si-modifying TiO(2) (ST) and P25 titania. The degradation of pentachlorophenol (PCP) in the microwave-assisted photocatalysis (MAPC) process was faster than other processes including microwave-assisted direct photolysis (MADP), microwave process alone (MP) and dark process (DP). The photocatalytic activity of FST is much higher than that of ST, FT and P25 titania. It may be attributed to its strong capacity of absorption to the UV-vis irradiation and more hydroxyl radical on surface of FST. In MPAC process, 40 mg L(-1) PCP was completely degraded in 20 min and its corresponding mineralization efficiency was 71%, the pH of solutions decreased from 10.3 to 6.47 and the dechlorination was completed in 12 min. The intermediates products of PCP in MAPC process identified by GC/MS were trichlorophenols (TCP), tetrachlorophenols (TTCP) and tetrachlorocatechol (TTCC) and the possible mechanism of PCP degradation is proposed. PMID:18555596

  2. A Novel Method for Preparation of Gold NanoBipyramids Using Microwave Irradiation and Its Application in Immunosensors

    NASA Astrophysics Data System (ADS)

    Huynh, Trong Phat; Ngo, Vo Ke Thanh; Nguyen, Dang Giang; Nguyen, Hoang Phuong Uyen; Nghiem, Quoc Dat; Lam, Quang Vinh; Huynh, Thanh Dat

    2016-05-01

    Gold nanobipyramids (NBPs) have attracted attention for producing smart sensing devices as diagnostic tools in biotechnological and medical applications, because they show more advantageous plasmonic properties than comparable gold nanorods. Normally, NBPs were synthesized using seed-mediated growth process at room temperature. In this report, our group describes a method for synthesising of NBPs using microwave irradiation with ascorbic acid reduction and cetyltrimethylammonium bromide + silver nitrate (AgNO3) as capping agents. The advantages of this method are a highly effective approach to fast and uniform NBPs. The product was characterized by ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, and x-ray powder diffraction. As an application in quartz crystal microbalance immunosensors, NBPs is conjugated with the chloramphenicol antibodies for signal amplification to detect chloramphenicol residuals in the QCM system.

  3. Cu2ZnSnS4 nanoflakes prepared by one step microwave irradiation technique: Effect of Cu concentration

    NASA Astrophysics Data System (ADS)

    Kandare, S. P.; Dhole, S. D.; Bhoraskar, V. N.; Dahiwale, S. S.

    2016-05-01

    Cu2ZnSnS4 (CZTS) nanoflakes were synthesized in one step by microwave irradiation method. Controlling the secondary phases in Copper Zinc Tin Sulfide (CZTS) material is critical, but it is necessary to control secondary phases in order to achieve the high efficiency solar cells made from CZTS. In the recent years, CZTS has shown its growing importance in thin film photovoltaic application because of its favorable optical and electrical properties. In this work, a systematic study has been carried out by properly controlling the copper concentration to get the pure phase of CZTS. X-ray diffraction shows the CZTS kesterite structure. Optical band gap estimated from UV-Visible spectroscopy was around 1.37eV. Systematic Raman study reveals the suppression of Cu2S peak with variation in copper concentration which otherwise was not clear from XRD and UV-visible data.

  4. On the acid-base properties of microwave irradiated hydrotalcite-like compounds containing Zn2+ and Mn2+.

    PubMed

    Sampieri, Alvaro; Lima, Enrique

    2009-04-01

    Microwave irradiated lamellar double hydroxides containing different divalent metals (Mn2+, Zn2+, or Mg2+) were prepared with Al3+ as the trivalent metal. Samples containing Mn2+ and Zn2+ were unstable at 400 degrees C, leading to formation of mixed oxides and spinel phases. Acid-base properties of the samples were characterized by nitromethane and CO2 adsorption followed by FTIR spectroscopy. Decomposition of adsorbed nitromethane leads to isocyanate species that acts as probe molecules of acid-base sites at the surface. These properties determine the ability of materials to retain CO2. Indeed, whereas Mn-O sites are able to interact directly with CO2 molecules, Mg-O and Zn-O are able to form carbonate species as a result of the CO2 sorption. PMID:19231817

  5. Influence of the Polyvinyl Pyrrolidone Concentration on Particle Size and Dispersion of ZnS Nanoparticles Synthesized by Microwave Irradiation

    PubMed Central

    Soltani, Nayereh; Saion, Elias; Erfani, Maryam; Rezaee, Khadijeh; Bahmanrokh, Ghazaleh; Drummen, Gregor P. C.; Bahrami, Afarin; Hussein, Mohd Zobir

    2012-01-01

    Zinc sulfide semiconductor nanoparticles were synthesized in an aqueous solution of polyvinyl pyrrolidone via a simple microwave irradiation method. The effect of the polymer concentration and the type of sulfur source on the particle size and dispersion of the final ZnS nanoparticle product was carefully examined. Microwave heating generally occurs by two main mechanisms: dipolar polarization of water and ionic conduction of precursors. The introduction of the polymer affects the heating rate by restriction of the rotational motion of dipole molecules and immobilization of ions. Consequently, our results show that the presence of the polymer strongly affects the nucleation and growth rates of the ZnS nanoparticles and therefore determines the average particle size and the dispersion. Moreover, we found that PVP adsorbed on the surface of the ZnS nanoparticles by interaction of the C–N and C=O with the nanoparticle’s surface, thereby affording protection from agglomeration by steric hindrance. Generally, with increasing PVP concentration, mono-dispersed colloidal solutions were obtained and at the optimal PVP concentration (5%), sufficiently small size and narrow size distributions were obtained from both sodium sulfide and thioacetamide sulfur sources. Finally, the sulfur source directly influences the reaction mechanism and the final particle morphology, as well as the average size. PMID:23202906

  6. Improvement in gate bias stress instability of amorphous indium-gallium-zinc oxide thin-film transistors using microwave irradiation

    SciTech Connect

    Jo, Kwang-Won; Cho, Won-Ju

    2014-11-24

    In this study, we evaluated the effects of microwave irradiation (MWI) post-deposition-annealing (PDA) treatment on the gate bias stress instability of amorphous indium-gallium-zinc oxide thin-film transistors (a-IGZO TFTs) and compared the results with a conventional thermal annealing PDA treatment. The MWI-PDA-treated a-IGZO TFTs exhibited enhanced electrical performance as well as improved long-term stability with increasing microwave power. The positive turn-on voltage shift (ΔV{sub ON}) as a function of stress time with positive bias and varying temperature was precisely modeled on a stretched-exponential equation, suggesting that charge trapping is a dominant mechanism in the instability of MWI-PDA-treated a-IGZO TFTs. The characteristic trapping time and average effective barrier height for electron transport indicate that the MWI-PDA treatment effectively reduces the defects in a-IGZO TFTs, resulting in a superior resistance against gate bias stress.

  7. Highly efficient, quick and green synthesis of biarlys with chitosan supported catalyst using microwave irradiation in the absence of solvent.

    PubMed

    Baran, Talat; Açıksöz, Eda; Menteş, Ayfer

    2016-05-20

    The aim of this study was to develop a quick reaction that had high activity with a small amount of catalyst, which could be an eco-friendly alternative technique for the synthesis of biarlys in Suzuki coupling reactions. First, a novel chitosan Schiff base supported Pd(II) catalyst was synthesized, and its structure was illuminated with FTIR, (1)H NMR, (13)C NMR, TG/DTG, SEM/EDAX, XRD, ICP-OES, UV-vis, magnetic moment, and molar conductivity techniques. Subsequently, the catalytic activity of the catalyst was tested in Suzuki CC reactions under microwave irradiation using a solvent-free reaction condition. The catalytic tests showed an excellent activity with a small load of the catalyst (0.02mol%) in 4min. The catalyst showed seven runs without loss of activity, and high values of turnover numbers (TON) and turnover frequency (TOF) were obtained. The novel biopolymer supported Pd(II) catalyst provided much faster reaction times, higher yields, and reusability under microwave heating compared to classic heating methods. PMID:26917390

  8. Simultaneous retrievals of cloud optical depth and droplet concentration from solar irradiance and microwave liquid water path

    NASA Astrophysics Data System (ADS)

    Boers, Reinout

    1997-12-01

    A 20-month time series of continuous observations of microwave radiation and solar irradiance was used to estimate the cloud optical depth and droplet number concentration at the Cape Grim Baseline Air Pollution Station, Tasmania, (40°41'S, 144°41'E). The data were selected by wind directions. When the air was from "baseline" origin, i.e., it had travelled over long oceanic distances and was mostly devoid of anthropogenic influences, the retrieved droplet concentration and optical depth were lower than when the air was from "nonbaseline" i.e., continental origin. Therefore the observed variation in cloud microphysical properties reflects the difference between the natural background conditions over the Southern Ocean and continental conditions with elevated droplet counts. Under baseline conditions the retrieved cloud optical depth exhibits a weak but perceptible seasonal cycle that has been previously observed from satellite data with a minimum in the austral winter, and a maximum in the austral summer. The results demonstrate that routine retrievals of cloud microphysical properties are possible using only a pyranometer and a microwave liquid water radiometer.

  9. Preparation of starch-poly-glutamic acid graft copolymers by microwave irradiation and the characterization of their properties.

    PubMed

    Xu, Jingyuan; Krietemeyer, Elizabeth F; Finkenstadt, Victoria L; Solaiman, Daniel; Ashby, Richard D; Garcia, Rafael A

    2016-04-20

    Graft copolymers of waxy maize starch and poly-γ-glutamic acid (PGA) were produced in an aqueous solution using microwave irradiation. The microwave reaction conditions were optimized with regard to temperature and pH. The temperature of 180°C and pH7.0 were the best reaction conditions resulting in a PGA graft of 0.45% based on nitrogen analysis. The average graft content and graft efficiency for the starch-PGA graft copolymer prepared at 180°C and pH7.0 were 4.20% and 2.73%, respectively. The starch-PGA graft copolymer produced at 180°C and pH7.0 could absorb more than 20 times its own weight amount of water and form a gel. The preliminary rheology study revealed that the starch-PGA graft copolymer gel exhibited viscoelastic solid behavior while the control sample of waxy starch showed viscoelastic liquid behavior. PMID:26876849

  10. Effect of low-level laser irradiating point on immunity

    NASA Astrophysics Data System (ADS)

    Cai, ChangSong; Qi, Qiong-fang; Xin, Jiang

    1993-03-01

    This paper reports that cellular immune function was observed when He-Ne laser was used to irradiate `zusanli' point in rats using various power, time, and periods. The indicator was a lymphocyte transformation test (LTT) by MTT colorimetric analysis. The best irradiating condition was determined, the effect and both virtues and defects of the laser were compared with those of electropuncture. The results show (1) LTT was enhanced in the group of laser irradiating point, but LTT was not enhanced in non-point (t' test, P < 0.01). (2) Lower power -- 2 mW or 5 mW of irradiating for 15 - 20 min, was better; 10 mW or 20 mW of irradiating for 10 - 15 min was suitable. Prolonged irradiating time did not enhance the immune function of the rats. On the contrary, immune function was inhibited. (3) A 7-day period of irradiating was best (once a day, 10 mW for 10 min). Enhanced LTT was not seen when irradiation days were added (SNK, P > 0.05). (4) Laser irradiation point and electropuncture were compared with vehicle control, LTT in the former two groups was enhanced significantly (ANOVA, P < 0.01), and laser irradiating point and electropuncture had the same effect (SNK, P > 0.05). The data suggest that laser irradiating point was able to enhance cell immunity and the enhancement of LTT had a point specific characteristic. The best condition of laser irradiating point was 2 mW for 15 - 20 min, and 10 mW or 20 mW for 10 - 15 min. The best period was 7-day irradiation. The results show laser irradiating the point may activate the main and collateral channels system, then modify the immune function of the body. Our observations provide experimental evidence for proper clinical application of laser irradiating points. The paper theoretically discusses and analyzes the experiment results in detail.

  11. Phase Transformation of VO2 Nanoparticles Assisted by Microwave Heating

    PubMed Central

    Sikong, Lek.

    2014-01-01

    The microwave assisted synthesis nowadays attracts a great deal of attention. Monoclinic phase VO2 (M) was prepared from NH4VO3 and H2C2O4 · 2H2O by a rapid microwave assisted technique. The synthesis parameters, microwave irradiation time, microwave power, and calcinations temperature were systematically varied and their influences on the structure and morphology were evaluated. The microwave power level has been carried out in range 180–600 W. TEM analysis demonstrated nanosized samples. The structural and morphological properties were measured using XRD, TEM, and thermal analyses. The variations of vanadium phase led to thermochromic properties. PMID:24688438

  12. Desilication of ZSM-5 zeolites for mesoporosity development using microwave irradiation

    SciTech Connect

    Hasan, Zubair; Jun, Jong Won; Kim, Chul-Ung; Jeong, Kwang-Eun; Jeong, Soon-Yong; Jhung, Sung Hwa

    2015-01-15

    Highlights: • Microwaves have beneficial effects on desilication of zeolites. • Produced mesopores with microwaves have narrow pore-size distribution. • Advantages and disadvantages of various desilicating agents were also reported. - Abstract: Mesoporous ZSM-5 zeolite was obtained by desilication in alkaline solutions with microwave (MW) and conventional electric (CE) heating under hydrothermal conditions. Both methods were effective in the production of mesoporous zeolites; however, MW was more efficient than CE as it led to well-defined mesopores with relatively small sizes and a narrow size distribution within a short treatment time. Moreover, the mesoporous ZSM-5 obtained through this method was effective in producing less bulky products from an acid-catalyzed reaction, specifically the butylation of phenol. Finally, various bases were found to have advantages and disadvantages in desilication. NaOH was the most reactive; however, macroporosity could develop easily under a severe condition. Ammonia water was weakly reactive; however, it could be used to precisely control the pore architecture, and no ion exchange is needed for acid catalysis. Organic amines such as ethylenediamine can also be used in desilication.

  13. [Spectroscopic study on CdS nanoparticles prepared by microwave irradiation].

    PubMed

    Cheng, Wei-qing; Liu, Di; Yan, Zheng-yu

    2008-06-01

    CdS nanoparticles capped by mercaptoacetic acid have been successfully synthesized by microwave method employing thioacetamide as sulfur source, which was proved to be a simple, rapid and specific mothod compared with traditional synthetical methods, such as precipitation, sol-gel, solvo-thermal method and so on. The concrete procedure synthesizing CdS nanoparticles was as follows: Cd(NO3)2 (40 mL, 5 mmol c L(-1)) was titrated with mercaptoacetic acid to pH 2.0, resulting in a turbid blue solution. NaOH (0.1 mol x L(-1)) was then added dropwise until the pH was 7 and the solution was again colorless. While quickly stirring the solution, 40 mL of 5 mmol x L(-1) CH3CSNH2 was added. Subsequently, the solution was adjusted to pH 9.0 and placed in a microwave oven for 25 min with power 30% (it means that if microwave works in a 30 s regime, it works 6 s, and does not work 24 s. This is some kind of pulse regime, but the totalpower is still 100%). This kind of nanoparticles were water-soluble and symmetrical. The diameter of CdS nanoparticles which have a spherical morphology was determined to be 12 nm by transmission electron microscopy(TEM), which posess perfect uniforminty. According to literatures report, there are two kinds of emission peak: one is edge-emission peak, and the other is surface blemish emission. In contrast to edge-emission peak, the surface blemish emission shows red shift on fluorescence spectra. In the present paper, the prominent peak of CdS QDs fluorescence spectrum was located at 490 nm, the humpbacked peak caused by surface blemish of CdS nanoparticles was located at 565 nm. However, the surface blemish emission was unconspicuous, thus we can conclude that the synthetical CdS QDs possesses excellent luminescence capability and favorable structure. The size and absorption and fluorescence spectra of CdS nanoparticles at different microwave power, pH value, reaction time and different sulfur source were investigated. The result showed that the

  14. Restraint chair with rowing-like movement for exposing exercising nonhuman primates to microwave irradiation

    SciTech Connect

    Knepton, J.; Ezell, C.; de Lorge, J.

    1983-04-20

    Design and construction of a Styrofoam exercise restraint chair is described for use with rhesus monkeys exposed to microwaves. Monkeys usually learn the rowing-like motion of the device within five 1-hour conditioning sessions. Radiation intensity measure of the chair and an example animal experiment demonstrated the chair's suitability for bioelectromagnetic studies. Results of a series of base-line behavioral sessions demonstrated concomitant exercise work load effects on colonic temperature, heart rate, correct response rate, and post-reinforcement pause time. With additional instrumentation, detection of minute disturbances of integrated psychological and physiological mechanisms by unusual environmental factors may be possible.

  15. Study of deep level characteristics in the neutrons irradiated Si structures by combining pulsed and steady-state spectroscopy techniques

    NASA Astrophysics Data System (ADS)

    Gaubas, E.; Kalendra, V.; Ceponis, T.; Uleckas, A.; Tekorius, A.; Vaitkus, J.; Velicka, A.

    2012-11-01

    The standard methods, such as capacitance deep level transient spectroscopy (C-DLTS) and thermally stimulated current (TSC) techniques are unsuitable for the analysis of heavily irradiated devices. In this work, therefore, several steady-state and pulsed techniques have been combined to comprehensively evaluate parameters of radiation defects and functional characteristics of the irradiated Si pin detectors. In order to understand defects created by radiation and evaluate their evolution with fluence, C-DLTS and TSC techniques have been employed to make a baseline identification of the radiation induced traps after irradiation with a rather small neutron fluence of 1012 cm-2. The steady-state photo-ionization spectroscopy (PIS) technique has been involved to correlate thermal- and photo- activation energies for definite radiation defects. A contactless technique for simultaneous measurements of the carrier lifetime and the parameters of deep levels based on microwave probed pulsed photo-conductivity (MW-PC) spectroscopy has been applied to correlate carrier capture cross-sections and densities of the identified different radiation defects. A technique for spectroscopy of deep levels in junction structures (BELIV) based on measurements of barrier capacitance charging current transient changes due to additional spectrally resolved pulsed illumination has been applied to evaluate the functional characteristics of the irradiated diodes. Pulsed spectroscopic measurements were implemented by combining the analysis of generation current and of barrier capacitance charging transients modified by a single fs pulse of illumination generated by an optical parametric oscillator of varied wavelength in the range from 0.5 to 10 μm. Several deep levels with activation energy in the range of 0.18-0.8 eV have been resolved from spectral analysis in the samples of Si grown by magnetic field applied Czochralski (MCz) technology.

  16. The effect of non-contact heating (microwave irradiation) and contact heating (annealing process) on properties and performance of polyethersulfone nanofiltration membranes

    NASA Astrophysics Data System (ADS)

    Mansourpanah, Y.; Madaeni, S. S.; Rahimpour, A.; Farhadian, A.

    2009-07-01

    In this work the effect of microwave irradiation on morphology and performance of polyethersulfone (PES) membranes was investigated. The membranes were prepared with 20 wt.% of PES by phase inversion method. N, N-dimethylformamide (DMF) and mixture of water and ethyl alcohol (90/10 vol.%) were employed as solvent and coagulant respectively. Polyvinylpirrolidone (PVP) with the concentration of 2 wt.% was selected as pore former. The effects of irradiation time (10, 30, 60, 90, 120 s) and microwave power (180, 360, 720 and 900 W) on structure and performance of membranes were studied. Increasing the irradiation time and power caused variation in permeate flux and ion rejection. Moreover, the effects of annealing processes (60, 70, 80 °C) were studied. Transmembrane pressure was selected around 1.5 MPa for all experiments. Scanning electron microscope (SEM) and atomic force microscope (AFM) were employed to describe the surface morphology of the prepared membranes. The effect of microwave irradiation time in different power revealed alterations in membrane surface morphology and AFM images represented that surface parameters (such as surface roughness) have been changed. The membrane exhibited moderate rejection (47%) and low permeate flux (4.5 kg/m 2 h) at 80 °C for NaCl solution. The SEM images indicate that the dense skin layer is formed at 80 °C annealing.

  17. GROWTH AND DEVELOPMENT OF MICE OFFSPRING AFTER IRRADIATION IN UTERO WITH 2,450-MHZ MICROWAVES

    EPA Science Inventory

    Mice offspring irradiated in utero with 2,450-MHz radio-frequency (RF) radiation at 0 or 28 mW/cm. sq. (whole-body averaged specific absorption rate = 0 or 16.5 W/kg) for 100 minutes daily on days 6 through 17 of gestation were evaluated for maturation and development on days 1, ...

  18. Hydrophilic and blue fluorescent N-doped carbon dots from tartaric acid and various alkylol amines under microwave irradiation

    NASA Astrophysics Data System (ADS)

    Xu, Minghan; Xu, Shusheng; Yang, Zhi; Shu, Mengjun; He, Guili; Huang, Da; Zhang, Liling; Li, Li; Cui, Daxiang; Zhang, Yafei

    2015-09-01

    The desired control of particle size, doping element composition, and surface structure of carbon dots (CDs) are vital for understanding the fluorescence mechanism and exploring their potential applications. Herein, nitrogen-doped CDs (N-doped CDs) have been synthesized with tartaric acid and various alkylol amines (monoethanolamine, biethanolamine and triethanolamine) under microwave irradiation. A systematic investigation was performed to characterize the N-doped CDs. It is found that with increasing nitrogen proportion, the fluorescent quantum yield and lifetime of N-doped CDs increases, whereas cell toxicity decreases. In other words, N-doped CDs synthesized by tartaric acid and monoethanolamine have the highest nitrogen content, the highest fluorescent quantum yield, the longest lifetime and the lowest cell toxicity. A corresponding mechanism has been proposed. Moreover, as-synthesized N-doped CDs have been applied for selectively detecting the Fe3+ ion and writing letters as a fluorescent ink.The desired control of particle size, doping element composition, and surface structure of carbon dots (CDs) are vital for understanding the fluorescence mechanism and exploring their potential applications. Herein, nitrogen-doped CDs (N-doped CDs) have been synthesized with tartaric acid and various alkylol amines (monoethanolamine, biethanolamine and triethanolamine) under microwave irradiation. A systematic investigation was performed to characterize the N-doped CDs. It is found that with increasing nitrogen proportion, the fluorescent quantum yield and lifetime of N-doped CDs increases, whereas cell toxicity decreases. In other words, N-doped CDs synthesized by tartaric acid and monoethanolamine have the highest nitrogen content, the highest fluorescent quantum yield, the longest lifetime and the lowest cell toxicity. A corresponding mechanism has been proposed. Moreover, as-synthesized N-doped CDs have been applied for selectively detecting the Fe3+ ion and writing

  19. Pyrolysis of oil palm empty fruit bunch biomass pellets using multimode microwave irradiation.

    PubMed

    Salema, Arshad Adam; Ani, Farid Nasir

    2012-12-01

    Oil palm empty fruit bunch pellets were subjected to pyrolysis in a multimode microwave (MW) system (1 kW and 2.45 GHz frequency) with and without the MW absorber, activated carbon. The ratio of biomass to MW absorber not only affected the temperature profiles of the EFB but also pyrolysis products such as bio-oil, char, and gas. The highest bio-oil yield of about 21 wt.% was obtained with 25% MW absorber. The bio-oil consisted of phenolic compounds of about 60-70 area% as detected by GC-MS and confirmed by FT-IR analysis. Ball lightning (plasma arc) occurred due to residual palm oil in the EFB biomass without using an MW absorber. The bio-char can be utilized as potential alternative fuel because of its heating value (25 MJ/kg). PMID:23026320

  20. SOLVENT-FREE CHEMICAL TRANSFORMATIONS USING MICROWAVE IRRADIATION. 32ND ACS CENTRAL REGIONAL MEETING, MAY 16-19, 2000, ABSTRACTS & PROGRAM, NORTHERN KENTUCKY CONVENTION CENTER, COVINGTON, KY. AMERICAN CHEMICAL SOCIETY, 1999, P. 121.

    EPA Science Inventory

    Microwave-expedited solvent-free synthetic processes will be described that involve the exposure of neat reactants to microwave (MW) irradiation in the presence of supported reagents or catalysts on minineral oxides. Recent developments will be presented on the synthetic utility...

  1. Fast transmethylation of total lipids in dried blood by microwave irradiation and its application to a population study.

    PubMed

    Lin, Yu Hong; Hanson, Jennifer A; Strandjord, Sarah E; Salem, Nicholas M; Dretsch, Michael N; Haub, Mark D; Hibbeln, Joseph R

    2014-08-01

    A methodology combining finger-pricked blood sampling, microwave accelerated fatty acid assay, fast gas chromatography data acquisition, and automated data processing was developed, evaluated and applied to a population study. Finger-pricked blood was collected on filter paper previously impregnated with 0.05 mg of the antioxidant butylated hydroxytoluene and air-dried at room temperature. Transmethylation was accelerated by microwave irradiation in an explosion-proof multimode microwave reaction system. The chemical procedure was based on a one-step direct transmethylation procedure catalyzed by acetyl chloride. The short-term stability of PUFA in blood dried on filter paper and storage at room temperature was examined using venous blood. The recoveries ranged from 97 to 101 % for the categorized fatty acids as well as the ratios of n-6 to n-3 PUFA and the n-3 % highly unsaturated fatty acid. Specifically, recoveries were 99, 98, 97, and 97 % for linoleic acid (18:2n-6), arachidonic acid (ARA), α-linolenic acid (ALA), and docosahexaenoic acid (DHA), respectively. The mol% (mean ± SD, 95 % confidence interval) of fatty acid composition in subjects from the population study was determined as 36.2 ± 3.8 (35.8, 36.7), 23.2 ± 3.0 (22.8, 23.5), 36.8 ± 3.5 (36.4, 37.2) and 3.79 ± 1.0 (3.68, 3.91) for the saturated, monounsaturated, n-6 and n-3 PUFA, respectively. Individually, the mean mol% (95 % CI) was 22.6 (22.3, 22.9) for 18:2n-6, 9.5 (9.3, 9.7) for ARA, 0.51 (0.49, 0.53) for ALA, 0.42 (0.38, 0.47) for eicosapentaenoic acid (EPA), and 1.67 (1.61, 1.73) for DHA. This methodology provides an accelerated yet high-efficiency, chemically safe, and temperature-controlled transmethylation, with diverse laboratory applications including population studies. PMID:24986160

  2. Fast Transmethylation of Total Lipids in Dried Blood by Microwave Irradiation and its Application to a Population Study

    PubMed Central

    Lin, Yu Hong; Hanson, Jennifer A.; Strandjord, Sarah E.; Salem, Nicholas M.; Dretsch, Michael N.; Haub, Mark D.; Hibbeln, Joseph R.

    2014-01-01

    A methodology combining finger-pricked blood sampling, microwave accelerated fatty acid assay, fast gas chromatography data acquisition, and automated data processing was developed, evaluated and applied to a population study. Finger-pricked blood was collected on filter paper previously impregnated with 0.05 mg of the antioxidant butylated hydroxytoluene and air-dried at room temperature. Transmethylation was accelerated by microwave irradiation in an explosion-proof multimode microwave reaction system. The chemical procedure was based on a one-step direct transmethylation procedure catalyzed by acetyl chloride. The short-term stability of PUFA in blood dried on filter paper and stored overnight at room temperature was examined using venous blood. The recoveries ranged from 97–101 % for the categorized fatty acids as well as the ratios of n-6 to n-3 PUFA and the n-3% highly unsaturated fatty acid. Specifically, recoveries were 99, 98, 97, and 97 % for linoleic acid (18:2n-6), arachidonic acid (ARA), α-linolenic acid (ALA), and docosahexaenoic acid (DHA), respectively. The mol% (mean ± SD, 95% confidence interval) of fatty acid composition in subjects from the population study was determined as 36.2±3.8 (35.8, 36.7), 23.2±3.0 (22.8, 23.5), 36.8±3.5 (36.4, 37.2) and 3.79±1.0 (3.68, 3.91) for the saturated, monounsaturated, n-6 and n-3 PUFA, respectively. Individually, the mean mol% (95% CI) was 22.6 (22.3, 22.9) for 18:2n-6, 9.5 (9.3, 9.7) for ARA, 0.51 (0.49, 0.53) for ALA, 0.42 (0.38, 0.47) for eicosapentaenoic acid (EPA), and 1.67 (1.61, 1.73) for DHA. This methodology provides an accelerated yet high-efficiency, chemically safe, and temperature-controlled transmethylation, with diverse laboratory applications including population studies. PMID:24986160

  3. Preparation of Pd supported on La(Sr)-Mn-O Perovskite by microwave Irradiation Method and Its Catalytic Performances for the Methane Combustion

    PubMed Central

    Wang, Wei; Yuan, Fulong; Niu, Xiaoyu; Zhu, Yujun

    2016-01-01

    In this work, a series of palladium supported on the La0.8Sr0.2MnO3.15 perovskite catalysts (Pd/LSM-x) with different Pd loading were prepared by microwave irradiation processing plus incipient wetness impregnation method and characterized by XRD, TEM, H2-TPR and XPS. These catalysts were evaluated on the lean CH4 combustion. The results show that the Pd/LSM-x samples prepared by microwave irradiation processing possess relative higher surface areas than LSM catalyst. The addition of Pd to the LSM leads to the increase in the oxygen vacancy content and the enhancement in the mobility of lattice oxygen which play an important role on the methane combustion. The Pd/LSM-3 catalysts with 4.2wt% Pd loading exhibited the best performance for CH4 combustion that temperature for 10% and 90% of CH4 conversion is 315 and 520 °C. PMID:26781628

  4. Preparation of Pd supported on La(Sr)-Mn-O Perovskite by microwave Irradiation Method and Its Catalytic Performances for the Methane Combustion

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Yuan, Fulong; Niu, Xiaoyu; Zhu, Yujun

    2016-01-01

    In this work, a series of palladium supported on the La0.8Sr0.2MnO3.15 perovskite catalysts (Pd/LSM-x) with different Pd loading were prepared by microwave irradiation processing plus incipient wetness impregnation method and characterized by XRD, TEM, H2-TPR and XPS. These catalysts were evaluated on the lean CH4 combustion. The results show that the Pd/LSM-x samples prepared by microwave irradiation processing possess relative higher surface areas than LSM catalyst. The addition of Pd to the LSM leads to the increase in the oxygen vacancy content and the enhancement in the mobility of lattice oxygen which play an important role on the methane combustion. The Pd/LSM-3 catalysts with 4.2wt% Pd loading exhibited the best performance for CH4 combustion that temperature for 10% and 90% of CH4 conversion is 315 and 520 °C.

  5. Preparation of Pd supported on La(Sr)-Mn-O Perovskite by microwave Irradiation Method and Its Catalytic Performances for the Methane Combustion.

    PubMed

    Wang, Wei; Yuan, Fulong; Niu, Xiaoyu; Zhu, Yujun

    2016-01-01

    In this work, a series of palladium supported on the La0.8Sr0.2MnO3.15 perovskite catalysts (Pd/LSM-x) with different Pd loading were prepared by microwave irradiation processing plus incipient wetness impregnation method and characterized by XRD, TEM, H2-TPR and XPS. These catalysts were evaluated on the lean CH4 combustion. The results show that the Pd/LSM-x samples prepared by microwave irradiation processing possess relative higher surface areas than LSM catalyst. The addition of Pd to the LSM leads to the increase in the oxygen vacancy content and the enhancement in the mobility of lattice oxygen which play an important role on the methane combustion. The Pd/LSM-3 catalysts with 4.2wt% Pd loading exhibited the best performance for CH4 combustion that temperature for 10% and 90% of CH4 conversion is 315 and 520 °C. PMID:26781628

  6. Coherent interaction with two-level fluctuators using near field scanning microwave microscopy

    NASA Astrophysics Data System (ADS)

    de Graaf, S. E.; Danilov, A. V.; Kubatkin, S. E.

    2015-11-01

    Near field Scanning Microwave Microscopy (NSMM) is a scanning probe technique that non-invasively can obtain material properties on the nano-scale at microwave frequencies. While focus has been on developing room-temperature systems it was recently shown that this technique can potentially reach the quantum regime, opening up for applications in materials science and device characterization in solid state quantum information processing. In this paper we theoretically investigate this new regime of NSMM. Specifically we show that interaction between a resonant NSMM probe and certain types of two-level systems become possible when the NSMM probe operates in the (sub-) single photon regime, and we expect a high signal-to-noise ratio if operated under the right conditions. This would allow to detect single atomic material defects with energy splittings in the GHz range with nano-scale resolution, provided that individual defects in the material under study are well enough separated. We estimate that this condition is fulfilled for materials with loss tangents below tan δ ˜ 10-3 which holds for materials used in today’s quantum circuits and devices where typically tan δ < 10-5. We also propose several extensions to a resonant NSMM that could improve sensitivity and functionality also for microscopes operating in a high power regime.

  7. Coherent interaction with two-level fluctuators using near field scanning microwave microscopy

    PubMed Central

    de Graaf, S. E.; Danilov, A. V.; Kubatkin, S. E.

    2015-01-01

    Near field Scanning Microwave Microscopy (NSMM) is a scanning probe technique that non-invasively can obtain material properties on the nano-scale at microwave frequencies. While focus has been on developing room-temperature systems it was recently shown that this technique can potentially reach the quantum regime, opening up for applications in materials science and device characterization in solid state quantum information processing. In this paper we theoretically investigate this new regime of NSMM. Specifically we show that interaction between a resonant NSMM probe and certain types of two-level systems become possible when the NSMM probe operates in the (sub-) single photon regime, and we expect a high signal-to-noise ratio if operated under the right conditions. This would allow to detect single atomic material defects with energy splittings in the GHz range with nano-scale resolution, provided that individual defects in the material under study are well enough separated. We estimate that this condition is fulfilled for materials with loss tangents below tan δ ∼ 10−3 which holds for materials used in today’s quantum circuits and devices where typically tan δ < 10−5. We also propose several extensions to a resonant NSMM that could improve sensitivity and functionality also for microscopes operating in a high power regime. PMID:26597218

  8. Coherent interaction with two-level fluctuators using near field scanning microwave microscopy.

    PubMed

    de Graaf, S E; Danilov, A V; Kubatkin, S E

    2015-01-01

    Near field Scanning Microwave Microscopy (NSMM) is a scanning probe technique that non-invasively can obtain material properties on the nano-scale at microwave frequencies. While focus has been on developing room-temperature systems it was recently shown that this technique can potentially reach the quantum regime, opening up for applications in materials science and device characterization in solid state quantum information processing. In this paper we theoretically investigate this new regime of NSMM. Specifically we show that interaction between a resonant NSMM probe and certain types of two-level systems become possible when the NSMM probe operates in the (sub-) single photon regime, and we expect a high signal-to-noise ratio if operated under the right conditions. This would allow to detect single atomic material defects with energy splittings in the GHz range with nano-scale resolution, provided that individual defects in the material under study are well enough separated. We estimate that this condition is fulfilled for materials with loss tangents below tan δ ∼ 10(-3) which holds for materials used in today's quantum circuits and devices where typically tan δ < 10(-5). We also propose several extensions to a resonant NSMM that could improve sensitivity and functionality also for microscopes operating in a high power regime. PMID:26597218

  9. Synthesis of Ketones through Microwave Irradiation Promoted Metal-Free Alkylation of Aldehydes by Activation of C(sp(3))-H Bond.

    PubMed

    Zhang, Xinying; Wang, Zhangxin; Fan, Xuesen; Wang, Jianji

    2015-11-01

    In this paper, a novel methodology for the synthesis of ketones via microwave irradiation promoted direct alkylation of aldehydes by activation of the inert C(sp(3))-H bond has been developed. Notably, the reactions were accomplished under metal-free conditions and used commercially available aldehydes and cycloalkanes as substrates without prefunctionalization. By using this novel method, an alternative synthetic approach toward the key intermediates for the preparation of the pharmaceutically valuable oxaspiroketone derivatives was successfully established. PMID:26457376

  10. Irradiation creep in austenitic and ferritic steels irradiated in a tailored neutron spectrum to induce fusion reactor levels of helium

    SciTech Connect

    Grossbeck, M.L.; Gibson, L.T.; Jitsukawa, S.

    1996-04-01

    Six austenitic stainless steels and two ferritic alloys were irradiated sequentially in two research reactors where the neutron spectrum was tailored to produce a He production rate typical of a fusion device. Irradiation began in the Oak Ridge Research Reactor where an atomic displacement level of 7.4 dpa was achieved and was then transferred to the High Flux Isotope Reactor for the remainder of the irradiation to a total displacement level of 19 dpa. Temperatures of 60 and 330{degree}C are reported on. At 330{degree}C irradiation creep was found to be linear in stress and fluence with rates in the range of 1.7 - 5.5 x 10{sup -4}% MPa{sup -1} dpa{sup -1}. Annealed and cold-worked materials exhibited similar creep rates. There is some indication that austenitic alloys with TiC or TiO precipitates had a slightly higher irradiation creep rate than those without. The ferritic alloys HT-9 and Fe-16Cr had irradiatoin creep rates about 0.5 x 10{sup -4}% MPa{sup -1} dpa{sup -1}. No meaningful data could be obtained from the tubes irradiated at 60{degree}C because of damage to the tubes.

  11. Synthesis of Visible-Light-Responsive Cu and N-Codoped AC/TiO2 Photocatalyst Through Microwave Irradiation

    NASA Astrophysics Data System (ADS)

    Tian, Fei; Wu, Zhansheng; Yan, Yujun; Ye, Bang-Ce; Liu, Dandan

    2016-06-01

    N-Cu-activated carbon (AC)/TiO2 nanoparticles were prepared by the sol-gel technique through microwave irradiation to modify the visible-light response of TiO2. Their structure, surface chemical composition, and optical absorption properties were characterized. The results showed that the codoped particles had a higher surface area and smaller particle size than pure AC/TiO2 and monodoped AC/TiO2. X-ray photoelectron spectroscopy of N-Cu-AC/TiO2 showed that Cu atoms replaced Ti atom sites, whereas N atoms occupied the O atom sites and interstitial sites in the TiO2 lattice, which changed the electric and band-gap structures of the photocatalyst. N or Cu monodoping of AC/TiO2 reduced the energy band gap of TiO2 from 2.86 eV to 2.81 or 2.61 eV, respectively. In (N, Cu)-codoped AC/TiO2, N and Cu were incorporated into the TiO2 framework and narrowed the band gap of TiO2 to 2.47 eV, causing a large red shift and enhancing visible-light utilization efficiency. Photocatalytic activities were further examined by formaldehyde degradation under visible-light irradiation. N-Cu-AC/TiO2 was found to have the highest activity (ca. 94.4 % formaldehyde degradation efficiency) and to be easily recyclable. These results show an important and innovative method of improving AC/TiO2 activity by modifying the nonmetallic and metallic species.

  12. Synthesis of Visible-Light-Responsive Cu and N-Codoped AC/TiO2 Photocatalyst Through Microwave Irradiation.

    PubMed

    Tian, Fei; Wu, Zhansheng; Yan, Yujun; Ye, Bang-Ce; Liu, Dandan

    2016-12-01

    N-Cu-activated carbon (AC)/TiO2 nanoparticles were prepared by the sol-gel technique through microwave irradiation to modify the visible-light response of TiO2. Their structure, surface chemical composition, and optical absorption properties were characterized. The results showed that the codoped particles had a higher surface area and smaller particle size than pure AC/TiO2 and monodoped AC/TiO2. X-ray photoelectron spectroscopy of N-Cu-AC/TiO2 showed that Cu atoms replaced Ti atom sites, whereas N atoms occupied the O atom sites and interstitial sites in the TiO2 lattice, which changed the electric and band-gap structures of the photocatalyst. N or Cu monodoping of AC/TiO2 reduced the energy band gap of TiO2 from 2.86 eV to 2.81 or 2.61 eV, respectively. In (N, Cu)-codoped AC/TiO2, N and Cu were incorporated into the TiO2 framework and narrowed the band gap of TiO2 to 2.47 eV, causing a large red shift and enhancing visible-light utilization efficiency. Photocatalytic activities were further examined by formaldehyde degradation under visible-light irradiation. N-Cu-AC/TiO2 was found to have the highest activity (ca. 94.4 % formaldehyde degradation efficiency) and to be easily recyclable. These results show an important and innovative method of improving AC/TiO2 activity by modifying the nonmetallic and metallic species. PMID:27295260

  13. A critical assessment of the specific role of microwave irradiation in the synthesis of ZnO micro- and nanostructured materials.

    PubMed

    Baghbanzadeh, Mostafa; Skapin, Srečo D; Orel, Zorica Crnjak; Kappe, C Oliver

    2012-04-27

    A rapid, microwave-assisted hydrothermal method has been developed to access ultrafine ZnO hexagonal microrods of about 3-4 μm in length and 200-300 nm in width by using a 1:5 zinc nitrate/urea precursor system. The size and morphology of these ZnO materials can be influenced by subtle changes in precursor concentration, solvent system, and reaction temperature. Optimized conditions involve the use of a 1:3 water/ethylene glycol solvent system and 10 min microwave heating at 150 °C in a dedicated single-mode microwave reactor with internal temperature control. Carefully executed control experiments ensuring identical heating and cooling profiles, stirring rates, and reactor geometries have demonstrated that for these preparations of ZnO microrods no differences between conventional and microwave dielectric heating are observed. The resulting ZnO microrods exhibited the same crystal phase, primary crystallite size, shape, and size distribution regardless of the heating mode. Similar results were obtained for the ultrafast preparation of ZnO nanoparticles with diameters of approximately 20 nm, synthesized by means of a nonaqueous sol-gel process at 200 °C from a Zn(acac)(2) (acac=acetylacetonate) precursor in benzyl alcohol. The specific role of microwave irradiation in enhancing these nanomaterial syntheses can thus be attributed to a purely thermal effect as a result of higher reaction temperatures, more rapid heating, and a better control of process parameters. PMID:22454084

  14. Cranial irradiation regulates CREB-BDNF signaling and variant BDNF transcript levels in the mouse hippocampus.

    PubMed

    Son, Yeonghoon; Yang, Miyoung; Kang, Sohi; Lee, Sueun; Kim, Jinwook; Kim, Juhwan; Park, Seri; Kim, Joong-Sun; Jo, Sung-Kee; Jung, Uhee; Shin, Taekyun; Kim, Sung-Ho; Wang, Hongbing; Moon, Changjong

    2015-05-01

    The brain can be exposed to ionizing radiation in various ways, and such irradiation can trigger adverse effects, particularly on learning and memory. However, the precise mechanisms of cognitive impairments induced by cranial irradiation remain unknown. In the hippocampus, brain-derived neurotrophic factor (BDNF) plays roles in neurogenesis, neuronal survival, neuronal differentiation, and synaptic plasticity. The significance of BDNF transcript variants in these contexts is becoming clearer. In the present study, both object recognition memory and contextual fear conditioning task performance in adult C57BL/6 mice were assessed 1 month after a single exposure to cranial irradiation (10 Gy) to evaluate hippocampus-related behavioral dysfunction following such irradiation. Furthermore, changes in the levels of BDNF, the cAMP-response element binding protein (CREB) phosphorylation, and BDNF transcript variants were measured in the hippocampus 1 month after cranial irradiation. On object recognition memory and contextual fear conditioning tasks, mice evaluated 1 month after irradiation exhibited significant memory deficits compared to sham-irradiated controls, but no apparent change was evident in locomotor activity. Both phosphorylated CREB and BDNF protein levels were significantly downregulated after irradiation of the hippocampus. Moreover, the levels of mRNAs encoding common BDNF transcripts, and exons IIC, III, IV, VII, VIII, and IXA, were significantly downregulated after irradiation. The reductions in CREB phosphorylation and BDNF expression induced by differential regulation of BDNF hippocampal exon transcripts may be associated with the memory deficits evident in mice after cranial irradiation. PMID:25792232

  15. Novel synthesis of holey reduced graphene oxide (HRGO) by microwave irradiation method for anode in lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Alsharaeh, Edreese; Ahmed, Faheem; Aldawsari, Yazeed; Khasawneh, Majdi; Abuhimd, Hatem; Alshahrani, Mohammad

    2016-07-01

    In this work, holey reduced graphene oxide (HRGO) was synthesized by the deposition of silver (Ag) nanoparticles onto the reduced graphene oxide (RGO) sheets followed by nitric acid treatment to remove Ag nanoparticles by microwave irradiation to form a porous structure. The HRGO were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), ultra violet-visible spectroscopy (UV-Vis), thermogravimetric analysis (TGA), and Raman spectroscopy. These novel HRGO exhibited high rate capability with excellent cycling stability as an anode material for lithium-ion batteries. The results have shown an excellent electrochemical response in terms of charge/discharge capacity (423 mAh/g at 100 mA/g). The cyclic performance was also exceptional as a high reversible capacity (400 mAh/g at 100 mA/g) was retained for 100 charge/discharge cycles. This fascinating electrochemical performance can be ascribed to their specific porous structure (2–5 nm pores) and high surface area (457 m2/g), providing numerous active sites for Li+ insertion, high electrical conductivity, low charge-transfer resistance across the electrolyte–electrode interface, and improved structural stability against the local volume change during Li+ insertion–extraction. Such electrodes are envisioned to be mass scalable with relatively simple and low-cost fabrication procedures, thereby providing a clear pathway toward commercialization.

  16. A novel combined pretreatment of ball milling and microwave irradiation for enhancing enzymatic hydrolysis of microcrystalline cellulose.

    PubMed

    Peng, Huadong; Li, Hongqiang; Luo, Hao; Xu, Jian

    2013-02-01

    Microcrystalline cellulose (MCC) was performed as a mode substrate to investigate its potential ability of bioconversion in a novel combined pretreatment of ball milling (BM) and/or microwave irradiation (MWI). The variation of structure characteristics of MCC before/after pretreatment were investigated, including crystallinity index (CrI), size of crystal (S(C)), specific surface area (SSA) and degree of polymerization (DP). Their correlation with the rate of enzymatic hydrolysis was differentiated by an optimized equation which indicated the rate of hydrolysis was much more sensitive to CrI than SSA and DP. To achieve the same or higher glucose yield of BM for 3h and 6h, BM for 1h with MWI for 20min could save 54.8% and 77.40% energy consumption, respectively. Moreover, chemicals were not required in this process. It is concluded that the combination of BM and short time MWI is an environment-friendly, economical and effective approach to treat biomass. PMID:23306114

  17. Novel synthesis of holey reduced graphene oxide (HRGO) by microwave irradiation method for anode in lithium-ion batteries.

    PubMed

    Alsharaeh, Edreese; Ahmed, Faheem; Aldawsari, Yazeed; Khasawneh, Majdi; Abuhimd, Hatem; Alshahrani, Mohammad

    2016-01-01

    In this work, holey reduced graphene oxide (HRGO) was synthesized by the deposition of silver (Ag) nanoparticles onto the reduced graphene oxide (RGO) sheets followed by nitric acid treatment to remove Ag nanoparticles by microwave irradiation to form a porous structure. The HRGO were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), ultra violet-visible spectroscopy (UV-Vis), thermogravimetric analysis (TGA), and Raman spectroscopy. These novel HRGO exhibited high rate capability with excellent cycling stability as an anode material for lithium-ion batteries. The results have shown an excellent electrochemical response in terms of charge/discharge capacity (423 mAh/g at 100 mA/g). The cyclic performance was also exceptional as a high reversible capacity (400 mAh/g at 100 mA/g) was retained for 100 charge/discharge cycles. This fascinating electrochemical performance can be ascribed to their specific porous structure (2-5 nm pores) and high surface area (457 m(2)/g), providing numerous active sites for Li(+) insertion, high electrical conductivity, low charge-transfer resistance across the electrolyte-electrode interface, and improved structural stability against the local volume change during Li(+) insertion-extraction. Such electrodes are envisioned to be mass scalable with relatively simple and low-cost fabrication procedures, thereby providing a clear pathway toward commercialization. PMID:27457356

  18. Performance improvement of the resistive memory properties of InGaZnO thin films by using microwave irradiation

    NASA Astrophysics Data System (ADS)

    Hwang, Yeong-Hyeon; An, Ho-Myoung; Cho, Won-Ju

    2014-01-01

    Microwave irradiation (MWI) at low temperature was employed in resistive random access memory (ReRAM) fabrication with InGaZnO (IGZO) thin-films as a switching medium, and the resistive switching behaviors were compared with conventional thermal annealing (CTA) process. A surface roughness of the MWI-treated IGZO layer is smoother than that of the CTA-treated layer. An electrical conduction mechanism of the MWI-treated device is similar to that of the pristine device, whereas the CTA device exhibits a different mechanism. After MWI treatment, the current ON/OFF ratio of IGZO ReRAMs significantly increased from 0.49 × 101 to 1.16 × 102, which was ascribed to the reduction in the OFF current. Further, the enlarged ON/OFF resistance window allowed sufficient data retention of >10 years at 85 °C. Owing to its smoother surface for stable resistive switching, low thermal budget, and process simplicity, MWI has great potential for metal-oxide ReRAMs in transparent and flexible system-on-panel applications.

  19. One pot synthesis, structural and spectral analysis of some symmetrical curcumin analogues catalyzed by calcium oxide under microwave irradiation

    NASA Astrophysics Data System (ADS)

    Elavarasan, S.; Bhakiaraj, D.; Chellakili, B.; Elavarasan, T.; Gopalakrishnan, M.

    2012-11-01

    A series of sixteen number of curcumin analogues have been synthesized under microwave irradiation using calcium oxide as a catalyst. The synthesized compounds have been characterized using FT-IR, MS, elemental analysis, 1H and 13C NMR spectroscopic techniques. The UV-Vis absorption studies for these compounds have been studied in order to provide the electronic transitions taking place in the molecule. When compared to the curcumin ((1E,4Z,6E)-5-hydroxy-1,7-bis(4-hydroxy-3-methoxyphenyl)hepta-1,4,6-trien-3-one), the absorption maxima, λmax for all the synthesized curcumin analogues with a variety of substituents gets blue shifted i.e., hypsochromic shift was observed. This shift may be assigned to the change of dipole moment within the solvated molecule. Theoretical calculations regarding the optimization of the synthesized molecules, electronic properties like highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) and mapped electron density surface diagrams were done. The geometrical energy, dipole moments and heat of formation values have also been calculated using the ArgusLab package by AM1 semi-empirical method.

  20. Microwave irradiated Ni-MnOx/C as an electrocatalyst for methanol oxidation in KOH solution for fuel cell application

    NASA Astrophysics Data System (ADS)

    Hameed, R. M. Abdel

    2015-12-01

    Ni-MnOx/C electrocatalyst was synthesized by the reduction of nickel precursor salt on MnOx/C powder using NaBH4 and the deposition process was motivated with the aid of microwave irradiation. Finer nickel nanoparticles were detected in Ni-MnOx/C using transmission electron microscopy with a lower particle size of 4.5 nm compared to 6 nm in Ni/C. Cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy (EIS) were applied to study the electrocatalytic activity of Ni-MnOx/C for methanol oxidation in 0.5 M KOH solution. The presence of 7.5 wt.% MnOx in Ni-MnOx/C enhanced the oxidation current density by 1.43 times. The catalytic rate constant of methanol oxidation at Ni-MnOx/C was calculated as 3.26 × 103 cm3 mol-1 s-1. An appreciable shift in the maximum frequency at the transition from the resistive to capacitive regions to a higher value in Bode plots of Ni-MnOx/C was shown when compared to Ni/C. It was accompanied by lowered phase angle values. The lowered Warburg impedance value (W) of Ni-MnOx/C at 400 mV confirmed the faster methanol diffusion rate at its surface.

  1. Influence of cetyltrimethylammonium bromide on the morphology of AWO 4 (A = Ca, Sr) prepared by cyclic microwave irradiation

    NASA Astrophysics Data System (ADS)

    Thongtem, Titipun; Kaowphong, Sulawan; Thongtem, Somchai

    2008-09-01

    AWO 4 (A = Ca, Sr) was prepared from metal salts [Ca(NO 3) 2·4H 2O or Sr(NO 3) 2], Na 2WO 4·2H 2O and different moles of cetyltrimethylammonium bromide (CTAB) in water by cyclic microwave irradiation. The structure of AWO 4 was characterized by X-ray diffraction (XRD) and selected area electron diffraction (SAED). Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) revealed the presence of nanoparticles in clusters with different morphologies; spheres, peaches with notches, dumb-bells and bundles, influenced by CTAB. Six Raman vibrational peaks of scheelite structure were detected at 908, 835, 793, 399, 332 and 210 cm -1 for CaWO 4 and 917, 833, 795, 372, 336 and 192 cm -1 for SrWO 4, which are assigned as ν1(A g), ν3(B g), ν3(E g), ν4(B g), ν2(A g) and νf.r.(A g), respectively. Fourier transform infrared (FTIR) spectra provided the evidence of W-O stretching vibration in [WO 4] 2- tetrahedrons at 793 cm -1 for CaWO 4 and 807 cm -1 for SrWO 4. The peaks of photoluminescence (PL) spectra were at 428-434 nm for CaWO 4, and 447-451 nm for SrWO 4.

  2. Novel synthesis of holey reduced graphene oxide (HRGO) by microwave irradiation method for anode in lithium-ion batteries

    PubMed Central

    Alsharaeh, Edreese; Ahmed, Faheem; Aldawsari, Yazeed; Khasawneh, Majdi; Abuhimd, Hatem; Alshahrani, Mohammad

    2016-01-01

    In this work, holey reduced graphene oxide (HRGO) was synthesized by the deposition of silver (Ag) nanoparticles onto the reduced graphene oxide (RGO) sheets followed by nitric acid treatment to remove Ag nanoparticles by microwave irradiation to form a porous structure. The HRGO were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), ultra violet-visible spectroscopy (UV-Vis), thermogravimetric analysis (TGA), and Raman spectroscopy. These novel HRGO exhibited high rate capability with excellent cycling stability as an anode material for lithium-ion batteries. The results have shown an excellent electrochemical response in terms of charge/discharge capacity (423 mAh/g at 100 mA/g). The cyclic performance was also exceptional as a high reversible capacity (400 mAh/g at 100 mA/g) was retained for 100 charge/discharge cycles. This fascinating electrochemical performance can be ascribed to their specific porous structure (2–5 nm pores) and high surface area (457 m2/g), providing numerous active sites for Li+ insertion, high electrical conductivity, low charge-transfer resistance across the electrolyte–electrode interface, and improved structural stability against the local volume change during Li+ insertion–extraction. Such electrodes are envisioned to be mass scalable with relatively simple and low-cost fabrication procedures, thereby providing a clear pathway toward commercialization. PMID:27457356

  3. Highly Sensitive Ethanol Sensor Based on Au-Decorated SnO2 Nanoparticles Synthesized Through Precipitation and Microwave Irradiation

    NASA Astrophysics Data System (ADS)

    Li, Yan; Zhao, Fang-Xian; Lian, Xiao-Xue; Zou, Yun-Ling; Wang, Qiong; Zhou, Qing-Jun

    2016-06-01

    Gold (Au)-decorated SnO2 nanoparticles (NPs) were synthesized through a precipitation and microwave irradiation process. The as-prepared products were characterized by x-ray diffraction and scanning electron microscopy. The results indicated that the as-prepared products consisted of nanometer-scale tetragonal crystalline SnO2 and face-centered cubic gold metal NPs. The gas sensing measurements showed that the sensor based on Au-decorated SnO2 NPs exhibited an extremely high response (239.5) toward 500-ppm ethanol at a relatively low working temperature (220°C). In addition, the response and recovery times of this sensor to ethanol were 1 s and 31 s, respectively. The excellent gas sensing performance of the synthesized NPs in terms of high response, fast response-recovery, superior selectivity, and good stability was attributed to the small nanometer size of the particles, Schottky barrier, and Au NP catalysis. Finally, we demonstrated that our Au-decorated SnO2 NPs could be a potential candidate for use in highly sensitive and selective gas sensors for ethanol.

  4. Synthesis and characterization of wires-like ZnO structures grown on a graphite support by microwave irradiation

    NASA Astrophysics Data System (ADS)

    Mora-Hernández, J. M.; Arce-Estrada, E. M.; Zarazúa-Villalobos, L.; Estrada-Flores, M.; Medina-Flores, J.; Reza-San Germán, C.

    2015-09-01

    Wires-like ZnO structures supported on graphite plates were synthesized by a microwave-assisted method using zinc oxide as precursor which was previously obtained from a chemical oxidation of zinc nitrate hexahydrate. Characterization was made by X-ray diffraction, scanning and high resolution transmission electron microscopy. X-ray diffraction results revealed that homemade ZnO showed the same diffraction peaks as its commercial counterpart, all reflections corresponds to a ZnO wurtzite hexagonal phase. After an irradiation process done at 2.45 GHz and an output power of 1200 W for 7 min, homemade ZnO showed a morphological transformation which can be appreciated in SEM micrographs resulting in the formation of the wires-like ZnO structures; these ones present a broadness between 150 to 200 nm and a variable length from 0.4 to 5 μm. Moreover, energy dispersive spectroscopy reveals that these structures present an entirely elemental zinc oxide composition. Wires-like ZnO structures use carbon plates as a support medium to perform their oriented growing. Finally, high resolution transmission electron microscopy showed that wires-like ZnO structures presents a crystalline arrangement with an interplanar distance of 2.4 Å corresponding to a preferential crystallographic orientation (101).

  5. Sewage sludge pretreatment by microwave irradiation combined with activated carbon fibre at alkaline pH for anaerobic digestion.

    PubMed

    Sun, Dedong; Guo, Sixiao; Ma, Nina; Wang, Guowen; Ma, Chun; Hao, Jun; Xue, Mang; Zhang, Xinxin

    2016-01-01

    This research focuses on the effects of microwave-assisted activated carbon fibre (ACF) (MW-ACF) treatment on sewage sludge at alkaline pH. The disintegration and biodegradability of sewage sludge were studied. It was found that the MW-ACF process at alkaline pH provided a rapid and efficient process to disrupt the microbial cells in the sludge. The results suggested that when irradiated at 800 W MW for 110 s with a dose of 1.0 g ACF/g solid concentration (SS) at pH 10.5, the MW-ACF pretreatment achieved 55% SS disintegration, 23% greater than the value of MW alone (32%). The concentration of total nitrogen, total phosphorus, supernatant soluble chemical oxygen demand, protein, and polysaccharide increased by 60%, 144%, 145%, 74%, and 77%, respectively. An increase in biogas production by 63.7% was achieved after 20 days of anaerobic digestion (AD), compared to the control. The results indicated that the MW-ACF pretreatment process at alkaline pH provides novel sludge management options in disintegration of sewage sludge for further AD. PMID:27332832

  6. Surfactant free rapid synthesis of hydroxyapatite nanorods by a microwave irradiation method for the treatment of bone infection

    NASA Astrophysics Data System (ADS)

    Vani, R.; Bharathi Raja, Subramaniya; Sridevi, T. S.; Savithri, K.; Niranjali Devaraj, S.; Girija, E. K.; Thamizhavel, A.; Narayana Kalkura, S.

    2011-07-01

    Mesoporous nanocrystalline hydroxyapatite (nHAp) rods of size 40-75 nm long and 25 nm wide (resembling bone mineral) were synthesized under microwave irradiation without using any surfactants or modifiers. The surface area and average pore size of the nHAp were found to be 32 m2 g - 1 and 4 nm, respectively. Rifampicin (RIF) and ciprofloxacin (CPF) loaded nHAp displayed an initial burst followed by controlled release (zero order kinetics). Combination of CPF and RIF loaded nHAp showed enhanced bacterial growth inhibition against Staphylococcus aureus (S aureus), Staphylococcus epidermidis (S epidermidis) and Escherichia coli (E coli) compared to individual agent loaded nHAp and pure nHAp. In addition, decreased bacterial adhesion (90%) was observed on the surface of CPF plus RIF loaded nHAp. The biocompatibility test toward MG63 cells infected with micro-organisms showed better cell viability and alkaline phosphatase activity (ALP) for the combination of CPF and RIF loaded nHAp. The influence on cell viability of infected MG63 cells was attributed to the simultaneous and controlled release of CPF and RIF from nHAp, which prevented the emergence of subpopulations that were resistant to each other. Hence, apart from the issue of the rapid synthesis of nHAp without surfactants or modifiers, the simultaneous and controlled release of dual drugs from nHAp would be a simple, non-toxic and cost-effective method to treat bone infections.

  7. Effect of extracorporeal ultraviolet blood irradiation on blood cholesterol level

    NASA Astrophysics Data System (ADS)

    Zalesskaya, G. A.; Laskina, O. V.; Mitkovskaya, N. P.; Kirkovsky, V. V.

    2012-07-01

    We have studied the effect of extracorporeal ultraviolet blood irradiation on cholesterol metabolism in patients with cardiovascular diseases. We have carried out a comprehensive analysis of the spectral characteristics of blood and plasma, gas-exchange and oximetry parameters, and the results of a complete blood count and chemistry panel before and after UV blood irradiation. We have assessed the changes in concentrations of cholesterols (total cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides) in the blood of the patients in response to a five-day course of UV blood irradiation. The changes in the spectral characteristics of blood and plasma, the chemistry panel, the gas composition, and the fractional hemoglobin composition initiated by absorption of UV radiation are used to discuss the molecular mechanisms for the effect of therapeutic doses of UV radiation on blood cholesterols.

  8. Afferent mechanisms of microwave-induced biological effects. Final report, June 1980-August 1987

    SciTech Connect

    Lai, H.; Horita, A.; Chou, C.K.; Guy, A.W.

    1987-08-12

    Effects of low-level microwave irradiation on neurological function were investigated in the rat. Results can be summarized in the following statements: (1) acute exposure effects the response of an animal to psychoactive drugs and changes cholinergic activity in the brain; (2) effects of microwaves are classically conditionable to environmental cues after repeated exposure. Tolerance can also develop after repeated exposure; and (3) endogenous opioids play a mediating role in certain neurological effects of microwaves. These data further our understanding on the neurological effects of microwave exposure and may have important implications in certain occupational situations in which repeated exposure to low-level microwaves is unavoidable.

  9. Circuit-level simulation of transistor lasers and its application to modelling of microwave photonic links

    NASA Astrophysics Data System (ADS)

    Iezekiel, Stavros; Christou, Andreas

    2015-03-01

    Equivalent circuit models of a transistor laser are used to investigate the suitability of this relatively new device for analog microwave photonic links. The three-terminal nature of the device enables transistor-based circuit design techniques to be applied to optoelectronic transmitter design. To this end, we investigate the application of balanced microwave amplifier topologies in order to enable low-noise links to be realized with reduced intermodulation distortion and improved RF impedance matching compared to conventional microwave photonic links.

  10. Microwave-assisted combustion synthesis of Ag/ZnO nanocomposites and their photocatalytic activities under ultraviolet and visible-light irradiation

    SciTech Connect

    Zhang, Dafeng; Pu, Xipeng; Li, Huaiyong; Yu, Young Moon; Shim, Jae Jeong; Cai, Peiqing; Kim, Sun Il; Seo, Hyo Jin

    2015-01-15

    Highlights: • Ag/ZnO nanocomposites were synthesized by a microwave-assisted combustion method. • Ag/ZnO nanocomposites exhibited improved photocatalytic activities under UV irradiation. • Poorer photocatalytic performances were obtained under visible-light irradiation. - Abstract: Ag/ZnO nanocomposites were synthesized by a rapid one-step microwave-assisted combustion method. The as-synthesized samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, photoluminescence and ultraviolet–visible spectrophotometry. XRD results showed that hexagonal ZnO and cubic Ag were obtained. Ag nanoparticles were chemically attached on the surface of ZnO. The decrease in the energy band gap of Ag/ZnO nanocomposites and the photoluminescence quenching were observed while the Ag content was increased. Furthermore, the introduction of Ag nanoparticles leads to significantly improved photocatalytic activities in the case of ultraviolet irradiation, but in the case of visible-light irradiation opposite results were obtained. The corresponding mechanism was discussed in detail.

  11. Effects of ionic conduction on hydrothermal hydrolysis of corn starch and crystalline cellulose induced by microwave irradiation.

    PubMed

    Tsubaki, Shuntaro; Oono, Kiriyo; Onda, Ayumu; Yanagisawa, Kazumichi; Mitani, Tomohiko; Azuma, Jun-ichi

    2016-02-10

    This study investigated the effects of ionic conduction of electrolytes under microwave field to facilitate hydrothermal hydrolysis of corn starch and crystalline cellulose (Avicel), typical model biomass substrates. Addition of 0.1M NaCl was effective to improve reducing sugar yield by 1.61-fold at unit energy (kJ) level. Although Avicel cellulose was highly recalcitrant to hydrothermal hydrolysis, addition of 0.1M MgCl2 improved reducing sugar yield by 6.94-fold at unit energy (kJ). Dielectric measurement of the mixture of corn starch/water/electrolyte revealed that ionic conduction of electrolytes were strongly involved in facilitating hydrothermal hydrolysis of polysaccharides. PMID:26686168

  12. Control of spontaneous emission from a microwave-field-coupled three-level{Lambda}-type atom in photonic crystals

    SciTech Connect

    Jiang, X. Q.; Zhang, B.; Sun, X. D.; Lu, Z. W.

    2011-05-15

    The spontaneous emission spectrum of a three-level {Lambda}-type atom driven by a microwave field was studied. For the two transitions coupled to the same modified reservoir, we discussed the influence of photonic band gap and Rabi frequency of the microwave field on the emission spectrum. The emission spectrum is given for different locations of the upper band-edge frequency. With the transition frequencies moving from outside the band gap to inside, the number of peaks decreases in the emission spectrum and the multipeak structure of spectral line is finally replaced by a strong non-Lorentzian shape. With increase of the Rabi frequency of the microwave field, we find the spectral line changes from a multipeak structure to a two-peak structure, originating from the inhibition of spontaneous emission for the corresponding decay channel.

  13. Foliar anatomical and morphological variation in Nothofagus pumilio seedlings under controlled irradiance and soil moisture levels.

    PubMed

    Ivancich, Horacio S; Lencinas, María V; Pastur, Guillermo J Martínez; Esteban, Rosina M Soler; Hernández, Luis; Lindstrom, Ivone

    2012-05-01

    Foliar anatomy and morphology are strongly related to physiological performance; therefore, phenotypic plasticity in leaves to variations in environmental conditions, such as irradiance and soil moisture availability, can be related to growth rate and survivorship, mainly during critical growth phases, such as establishment. The aim of this work was to analyze changes in the foliar internal anatomy (tissue proportions and cell dimensions) and external morphology (leaf length, width and area) of Nothofagus pumilio (Poepp. et Endl.) Krasser seedlings growing in a greenhouse under controlled irradiance (three levels) and soil moisture (two levels) during one growing season (measured three times), and to relate them to physiological traits. Three irradiance levels (4, 26 and 64% of the natural incident light) and two soil moisture levels (40 and 80% soil capacity) were evaluated during November, January and March. Internal foliar anatomy of seedlings was analyzed using digital photographs of histological cuttings, while leaf gross morphology was measured using digital calipers and image analysis software. Most internal anatomical variables presented significant differences under different irradiance levels during the growing season, but differences were not detected between soil moisture levels. Palisade parenchyma was the tissue most sensitive to irradiance levels, and high irradiance levels (64% natural incident light) produced greater values in most of the internal anatomical variables than lower irradiance levels (4-24% natural incident light). Complementarily, larger leaves were observed in medium and low irradiance levels, as well as under low soil moisture levels (40% soil capacity). The relationship of main results with some eco-physiological traits was discussed. Foliar internal anatomical and external morphological plasticity allows quick acclimation of seedlings to environmental changes (e.g., during harvesting). These results can be used to propose new

  14. Fabrication of high-performance ultra-thin-body SnO{sub 2} thin-film transistors using microwave-irradiation post-deposition annealing

    SciTech Connect

    Jo, Kwang-Won; Moon, Sung-Wan; Cho, Won-Ju

    2015-01-26

    We report on the fabrication of high-performance ultra-thin-body (UTB) SnO{sub 2} thin-film transistors (TFTs) using microwave-irradiation post-deposition annealing (PDA) at a low process temperature (<100 °C). We confirm that the electrical characteristics of SnO{sub 2} TFTs become drastically enhanced below a body thickness of 10 nm. The microwave-annealed UTB SnO{sub 2} TFTs with a thickness of 5 nm exhibited increased optical transmittance, as well as remarkable transfer characteristics: a high mobility of 35.4 cm{sup 2} V{sup −1} s{sup −1}, a drain current on/off ratio of 4.5 × 10{sup 7}, a steep subthreshold gate voltage swing of 623 mV/dec, and a clear enhancement-mode behavior. Additionally, the microwave-annealed SnO{sub 2} TFTs exhibited a better positive gate-bias stress/negative gate-bias stress immunity than thermally annealed SnO{sub 2} TFTs. Therefore, the thickness of the UTB SnO{sub 2} TFTs, as well as the microwave-annealing process, are both shown to be essential for transparent and flexible display technology.

  15. Dynamics of a three-level V-type atom driven by a cavity photon and microwave field

    NASA Astrophysics Data System (ADS)

    Yan-Li, Xue; Shi-Deng, Zhu; Ju, Liu; Ting-Hui, Xiao; Bao-Hua, Feng; Zhi-Yuan, Li

    2016-04-01

    We discuss the dynamics of a three-level V-type atom driven simultaneously by a cavity photon and microwave field by examining the atomic population evolution. Owing to the coupling effect of the cavity photon, periodical oscillation of the population between the two upper states and the ground state takes place, which is the well-known vacuum Rabi oscillation. Meanwhile, the population exchange between the upmost level and the middle level can occur due to the driving action of the external microwave field. The general dynamic behavior is the superposition of a fast and a slow periodical oscillation under the cooperative and competitive effect of the cavity photon and the microwave field. Numerical results demonstrate that the time evolution of the population is strongly dependent on the atom–cavity coupling coefficient g and Rabi frequency Ω e that reflects the intensity of the external microwave field. By modulating the two parameters g and Ω e, a large number of population transfer behaviors can be achieved. Project supported by the National Natural Science Foundation of China (Grant Nos. 11434017 and 11374357) and the National Basics Research Program of China (Grant No. 2013CB632704).

  16. Central nervous system transplantation benefited by low-level laser irradiation

    NASA Astrophysics Data System (ADS)

    Rochkind, S.; Lubart, Rachel; Wollman, Yoram; Simantov, Rabi; Nissan, Moshe; Barr-Nea, Lilian

    1990-06-01

    Effect of low-level laser irradiation on the central nervous system transplantation is reported. Ernbryonal brain allografts were transplanted into the brain of 20 adult rats and peripheral nerve graft transplanted into the severely injured spinal cord of 16 dogs. The operated wound of 10 rats and 8 dogs were exposed daily for 21 days to lowpower laser irradiation CW HeNe laser (35 mW, 632.8 run, energy density of 30 J/cm2 at each point for rats and 70 J/cm2 at each point for dogs). This study shows that (i) the low-level laser irradiation prevents extensive glial scar formation (a limiting factor in CNS regeneration) between embryonal transplants and host brain; (ii) Dogs made paraplegic by spinal cord injury were able to walk 3-6 months later. Recovery of these dogs was effected by the implantation of a fragment of autologous sciatic nerve at the site of injury and subsequently exposing the dogs to low-level laser irradiation. The effect of laser irradiation on the embryonal nerve cells grown in tissue culture was also observed. We found that low-level laser irradiation induced intensive migration of neurites outward of the aggregates 15-22 The results of the present study and our previous investigations suggest that low-level laser irradiation is a novel tool for treatment of peripheral and central nervous system injuries.

  17. Towards microwave imaging of single two-level defects in dielectric materials

    NASA Astrophysics Data System (ADS)

    de Graaf, Sebastian; Danilov, Andrey; Tzalenchuk, Alexander; Kubatkin, Sergey

    Two-level fluctuators (TLF) are a major source of decoherence in quantum devices and significant effort is invested towards better understanding and eliminating these types of material defects. Here we propose that a near-field scanning microwave microscope (NSMM) can be used to image individual two-level defects on the nano-scale, provided that such a microscope operates in the right regime. Not only would such a 'coherent' NSMM be able to obtain nano-scale spatial distributions of defects and their locations within dielectric materials, it would also be able to determine the relative orientation of the TLF dipole with respect to the dielectric crystal, giving vital information about the nature of the TLF. We theoretically describe the operation and capabilities of a 'coherent' NSMM and show that individual defects can be imaged in dielectric materials with low enough loss tangent, such as sapphire and silicon dioxide, relevant for solid state quantum technologies. We describe the requirements for constructing such an NSMM and report on our recent progress in setting up this technology.

  18. Level crossing analysis of cosmic microwave background radiation: a method for detecting cosmic strings

    SciTech Connect

    Movahed, M. Sadegh; Khosravi, Shahram E-mail: khosravi@ipm.ir

    2011-03-01

    In this paper we study the footprint of cosmic string as the topological defects in the very early universe on the cosmic microwave background radiation. We develop the method of level crossing analysis in the context of the well-known Kaiser-Stebbins phenomenon for exploring the signature of cosmic strings. We simulate a Gaussian map by using the best fit parameter given by WMAP-7 and then superimpose cosmic strings effects on it as an incoherent and active fluctuations. In order to investigate the capability of our method to detect the cosmic strings for the various values of tension, Gμ, a simulated pure Gaussian map is compared with that of including cosmic strings. Based on the level crossing analysis, the superimposed cosmic string with Gμ∼>4 × 10{sup −9} in the simulated map without instrumental noise and the resolution R = 1' could be detected. In the presence of anticipated instrumental noise the lower bound increases just up to Gμ∼>5.8 × 10{sup −9}.

  19. Microwave short-pulse bed-level detector. Annual report, January 1-December 31, 1981

    SciTech Connect

    Balanis, C.A.; Delauder, D.M.

    1981-01-01

    A short-pulse microwave system for measuring the bed-level within a fluidized-bed combustor, has been designed, built, and laboratory tested on static beds. The system is a short-pulse radar which operates in the frequency region of 6.75 to 10.95 GHz as a time-domain measurement system. Laboratory measurements of static bed-levels, for smooth and corrugated surfaces of metal plates and limestone sand, agree to an average of 2.0% of the actual heights. Additionally, the system was tested with a dielectric thermal protector, which did not compromise the accuracy of the measurements. Analytical models have been formulated to provide insight into the operation of the system on a wide range of simulated targets without the necessity of performing expensive and difficult laboratory experiments. Two formulations have been used to describe electromagnetic scattering by a rough surface as a function of frequency: the space harmonic model and the physical optics model. A reconstruction technique has been devised which uses the scattering models and the spectrum of the transmitted pulse to synthesize the reflected pulse. The data generated by the models compare well to previously published data and to experimental results.

  20. Acute UV irradiation increases heparan sulfate proteoglycan levels in human skin.

    PubMed

    Jung, Ji-Yong; Oh, Jang-Hee; Kim, Yeon Kyung; Shin, Mi Hee; Lee, Dayae; Chung, Jin Ho

    2012-03-01

    Glycosaminoglycans are important structural components in the skin and exist as various proteoglycan forms, except hyaluronic acid. Heparan sulfate (HS), one of the glycosaminoglycans, is composed of repeated disaccharide units, which are glucuronic acids linked to an N-acetyl-glucosamine or its sulfated forms. To investigate acute ultraviolet (UV)-induced changes of HS and HS proteoglycans (HSPGs), changes in levels of HS and several HSPGs in male human buttock skin were examined by immunohistochemistry and real-time quantitative polymerase chain reaction (qPCR) after 2 minimal erythema doses (MED) of UV irradiation (each n = 4-7). HS staining revealed that 2 MED of UV irradiation increased its expression, and staining for perlecan, syndecan-1, syndecan-4, CD44v3, and CD44 showed that UV irradiation increased their protein levels. However, analysis by real-time qPCR showed that UV irradiation did not change mRNA levels of CD44 and agrin, and decreased perlecan and syndecan-4 mRNA levels, while increased syndecan-1 mRNA level. As HS-synthesizing or -degrading enzymes, exostosin-1 and heparanase mRNA levels were increased, but exostosin-2 was decreased by UV irradiation. UV-induced matrix metalloproteinase-1 expression was confirmed for proper experimental conditions. Acute UV irradiation increases HS and HSPG levels in human skin, but their increase may not be mediated through their transcriptional regulation. PMID:22379342

  1. Level-crossing enhancement of the microwave ionization of highly excited hydrogen atoms

    SciTech Connect

    Bayfield, J.E.; Luie, S.Y.

    1993-05-01

    For quasi one-dimensional atoms, we have observed oscillatory ionization probability as a function of microwave field strength, well below the threshold for classical chaos. This occurs within the microwave/Kepler frequency ratio rage 0.45-0.56. A Landau-Zener model modified to include ionizations of one quasienergy eigenstate can fit the data, there are Stuckelberg oscillations arising from occurring during the rise and fall of pulse. Varying the principal quantum number of the atom reveals a large degree of classical scaling, indicating that the quasienergy states involved are largely semiclassical. Observable changes in the data can result from a 0.2% change in microwave frequency.

  2. Development, Test, and Evaluation of Microwave Radar Water Level (MWWL) Sensors' Wave Measurement Capability

    NASA Astrophysics Data System (ADS)

    Iyer, S. K.; Heitsenrether, R.

    2015-12-01

    Waves can have a significant impact on many coastal operations including navigational safety, recreation, and even the economy. Despite this, as of 2009, there were only 181 in situ real-time wave observation networks nationwide (IOOS 2009). There has recently been interest in adding real-time wave measurement systems to already existing NOAA Center for Operational Oceanographic Products and Services (CO-OPS) stations. Several steps have already been taken in order to achieve this, such as integrating information from existing wave measurement buoys and initial testing of multiple different wave measurement systems (Heitsenrether et al. 2012). Since wave observations can be derived from high frequency water level changes, we will investigate water level sensors' capability to measure waves. Recently, CO-OPS has been transitioning to new microwave radar water level (MWWL) sensors which have higher resolution and theoretically a greater potential wave measurement capability than the acoustic sensors in stilling wells. In this study, we analyze the wave measurement capability of MWWL sensors at two high energy wave environments, Duck, NC and La Jolla, CA, and compare results to two "reference" sensors (A Nortek acoustic waves and currents profiler (AWAC) at Duck and a single point pressure sensor at La Jolla). A summary of results from the two field test sites will be presented, including comparisons of wave energy spectra, significant wave height, and peak period measured by the test MWWL sensors and both reference AWAC and pressure sensors. In addition, relationships between MWWL versus reference wave sensor differences and specific wave conditions will be discussed. Initial results from spectral analysis and the calculation of bulk wave parameters indicate that MWWL sensors set to the "NoFilter" processing setting can produce wave measurements capability that compare well to the two reference sensors. These results support continued development to enable the

  3. Controllable microwave three-wave mixing via a single three-level superconducting quantum circuit.

    PubMed

    Liu, Yu-xi; Sun, Hui-Chen; Peng, Z H; Miranowicz, Adam; Tsai, J S; Nori, Franco

    2014-01-01

    Three-wave mixing in second-order nonlinear optical processes cannot occur in atomic systems due to the electric-dipole selection rules. In contrast, we demonstrate that second-order nonlinear processes can occur in a superconducting quantum circuit (i.e., a superconducting artificial atom) when the inversion symmetry of the potential energy is broken by simply changing the applied magnetic flux. In particular, we show that difference- and sum-frequencies (and second harmonics) can be generated in the microwave regime in a controllable manner by using a single three-level superconducting flux quantum circuit (SFQC). For our proposed parameters, the frequency tunability of this circuit can be achieved in the range of about 17 GHz for the sum-frequency generation, and around 42 GHz (or 26 GHz) for the difference-frequency generation. Our proposal provides a simple method to generate second-order nonlinear processes within current experimental parameters of SFQCs. PMID:25487352

  4. Selective oxidation of rhodinol to citral using H{sub 2}O{sub 2}-platinum black system under microwave irradiation

    SciTech Connect

    Chong, D. J. W.; Latip, J.; Hasbullah, S. A.; Sastrohamidjojo, H.

    2014-09-03

    The oxidation method utilising H{sub 2}O{sub 2}-Pt black system was successfully adapted in the oxidation of rhodinol which is a mixture form of geraniol and citronellol. This green oxidation found to be selectively converted geraniol to citral using conventional method. The implementation of microwave irradiation (175 Watt, 90°C, 30 mins) and a higher molar of H{sub 2}O{sub 2} further improved the conversion rate (72.6%) and selectivity (81%) as compared to the conventional method.

  5. Expression of fas protein on CD4+T cells irradiated by low level He-Ne

    NASA Astrophysics Data System (ADS)

    Nie, Fan; Zhu, Jing; Zhang, Hui-Guo

    2005-07-01

    Objective: To investigate the influence on the Expression of Fas protein on CD4+ T cells irradiated by low level He-Ne laser in the cases of psoriasis. Methods:the expression of CD4+ T Fas protein was determined in the casee of psoriasis(n=5) pre and post-low level laser irradiation(30 min、60min and 120min)by flow cytometry as compared withthe control(n=5). Results:In the cases of psoriasis,the expression of CD4+T FAS protein 21.4+/-3.1% was increased significantly than that of control group 16.8+/-2.1% pre-irradiation, p<0.05in the control,there is no difference between pre and post- irradiation,p>0.05in the cases , the expression of CD4+T Fas protein wae positively corelated to the irradiation times, when the energy density arrived to 22.92J/cm2(60 minutes)and 45.84J/cm2(120minutes), the expression of CD4+ T Fas protein was increased significantly as compared with pre-irradiation,p<0.05.Conclusion: The expression of CD4+T Fas protein may be increased by low level He-Ne laser irradiation ,the uncontrolled status of apoptosis could be corrected.

  6. Scalable Microwave Addressing of Trapped Ion Qubits at Fault-tolerant Error Levels

    NASA Astrophysics Data System (ADS)

    Prado Lopes Aude Craik, Diana; Linke, Norbert; Allcock, David; Harty, Thomas; Sepiol, Martin; Stacey, Derek; Steane, Andrew; Lucas, David

    2015-05-01

    We present results obtained with a two-zone, scalable prototype surface-electrode ion trap for storing and individually addressing memory qubits. The trap has 4 integrated microwave electrodes per zone, designed to provide enough degrees of freedom for independent, parallel control of the microwave field amplitude, phase and polarization at each ion. In a demonstration experiment, we use two trap electrodes, one in each zone, to drive Rabi flops in a Calcium-43 ion trapped in the zone we wish to address, while nulling the microwave field in the neighbor zone. We measure Rabi frequency ratios between the addressed and nulled zones of up to 1400, implying that spin-flip errors of order 10-6 are achievable. We also demonstrate polarization control of the microwave field by selectively driving one of two near-degenerate transitions out of the qubit states, one of which is driven by σ+ polarization and the other by σ- polarization. We null the σ+ component of the microwave field at the ion and measure a Rabi frequency ratio of ~ 350 between the σ- and σ+ transitions. Finally, a new design concept for scalable microwave surface-electrode ion traps is presented and progress on the next-generation prototype is reported. This work is supported by the US Army Research Office, EPSRC (UK) and the UK National Quantum Technologies Programme.

  7. New type of B-periodic magneto-oscillations in a two-dimensional electron system induced by microwave irradiation.

    PubMed

    Kukushkin, I V; Akimov, M Yu; Smet, J H; Mikhailov, S A; von Klitzing, K; Aleiner, I L; Falko, V I

    2004-06-11

    We observe a new type of magneto-oscillations in the photovoltage and the longitudinal resistance of a two-dimensional electron system. The oscillations are induced by microwave radiation and are periodic in magnetic field. The period is determined by the microwave frequency, the electron density, and the distance between potential probes. The phenomenon is accounted for by interference of coherently excited edge magnetoplasmons in the contact regions and offers perspectives for developing new tunable microwave and terahertz detection schemes and spectroscopic techniques. PMID:15245184

  8. Optimization of bio-diesel production from soybean and wastes of cooked oil: combining dielectric microwave irradiation and a SrO catalyst.

    PubMed

    Koberg, Miri; Abu-Much, Riam; Gedanken, Aharon

    2011-01-01

    This work offers an optimized method in the transesterification of pristine (soybean) oil and cooked oil to bio-diesel, based on microwave dielectric irradiation as a driving force for the transesterification reaction and SrO as a catalyst. This combination has demonstrated excellent catalytic activity and stability. The transesterification was carried out with and without stirring. According to 1H NMR spectroscopy and TLC results, this combination accelerates the reaction (to less than 60 s), maintaining a very high conversion (99%) and high efficiency. The catalytic activity of SrO under atmospheric pressure in the presence of air and under the argon atmosphere is demonstrated. The optimum conversion of cooked oil (99.8%) is achieved under MW irradiation of 1100 W output with magnetic stirring after only 10 s. The optimum method decreases the cost of bio-diesel production and has the potential for industrial application in the transesterification of cooked oil to bio-diesel. PMID:20833538

  9. An experimental model to determine the level of antibiotics in irradiated tissues

    SciTech Connect

    Cruz, N.I.; Ariyan, S.; Miniter, P.; Andriole, V.T.

    1984-05-01

    An experimental study was designed using male Sprague-Dawley rats treated with a single dose of 1800 rads to an area of skin and soft tissue of the back measuring 2 X 3 cm. This dose was estimated to produce changes equivalent to 6000 rads in divided doses over 6 weeks. At intervals of 5, 10, and 15 weeks after irradiation, punch biopsies were taken from both irradiation, and nonirradiated skin areas of each animal 30 minutes after the intraperitoneal administration of gentamicin. Skin homogenates were prepared, and the antibiotic levels in these samples were determined by a bacterial growth inhibition assay. The antibiotic levels were found to be equal (16.1 +/- 6 micrograms/ml vs. 16.0 +/- 5 micrograms/ml) in both irradiated and nonirradiated skin at 5 weeks after radiation. However, at 10 and 15 weeks after radiation, the antibiotic levels had dropped to 9.9 +/- 3 micrograms/ml in irradiated skin compared with 14.1 +/- 4 micrograms/ml in normal skin (p less than 0.001) and with 5.4 micrograms/ml in irradiated skin vs. 11.8 +/- 5 micrograms/ml in nonirradiated skin (p less than 0.001), respectively. Results demonstrate that in spite of adequate gentamicin levels in the circulation and nonirradiated tissue in rats, gentamicin has a decreasing ability to diffuse into irradiated tissues with increasing intervals after therapeutic doses of radiation.

  10. Single microwave-photon detector using an artificial Λ-type three-level system.

    PubMed

    Inomata, Kunihiro; Lin, Zhirong; Koshino, Kazuki; Oliver, William D; Tsai, Jaw-Shen; Yamamoto, Tsuyoshi; Nakamura, Yasunobu

    2016-01-01

    Single-photon detection is a requisite technique in quantum-optics experiments in both the optical and the microwave domains. However, the energy of microwave quanta are four to five orders of magnitude less than their optical counterpart, making the efficient detection of single microwave photons extremely challenging. Here we demonstrate the detection of a single microwave photon propagating through a waveguide. The detector is implemented with an impedance-matched artificial Λ system comprising the dressed states of a driven superconducting qubit coupled to a microwave resonator. Each signal photon deterministically induces a Raman transition in the Λ system and excites the qubit. The subsequent dispersive readout of the qubit produces a discrete 'click'. We attain a high single-photon-detection efficiency of 0.66±0.06 with a low dark-count probability of 0.014±0.001 and a reset time of ∼400 ns. This detector can be exploited for various applications in quantum sensing, quantum communication and quantum information processing. PMID:27453153

  11. Single microwave-photon detector using an artificial Λ-type three-level system

    NASA Astrophysics Data System (ADS)

    Inomata, Kunihiro; Lin, Zhirong; Koshino, Kazuki; Oliver, William D.; Tsai, Jaw-Shen; Yamamoto, Tsuyoshi; Nakamura, Yasunobu

    2016-07-01

    Single-photon detection is a requisite technique in quantum-optics experiments in both the optical and the microwave domains. However, the energy of microwave quanta are four to five orders of magnitude less than their optical counterpart, making the efficient detection of single microwave photons extremely challenging. Here we demonstrate the detection of a single microwave photon propagating through a waveguide. The detector is implemented with an impedance-matched artificial Λ system comprising the dressed states of a driven superconducting qubit coupled to a microwave resonator. Each signal photon deterministically induces a Raman transition in the Λ system and excites the qubit. The subsequent dispersive readout of the qubit produces a discrete `click'. We attain a high single-photon-detection efficiency of 0.66+/-0.06 with a low dark-count probability of 0.014+/-0.001 and a reset time of ~400 ns. This detector can be exploited for various applications in quantum sensing, quantum communication and quantum information processing.

  12. Single microwave-photon detector using an artificial Λ-type three-level system

    PubMed Central

    Inomata, Kunihiro; Lin, Zhirong; Koshino, Kazuki; Oliver, William D.; Tsai, Jaw-Shen; Yamamoto, Tsuyoshi; Nakamura, Yasunobu

    2016-01-01

    Single-photon detection is a requisite technique in quantum-optics experiments in both the optical and the microwave domains. However, the energy of microwave quanta are four to five orders of magnitude less than their optical counterpart, making the efficient detection of single microwave photons extremely challenging. Here we demonstrate the detection of a single microwave photon propagating through a waveguide. The detector is implemented with an impedance-matched artificial Λ system comprising the dressed states of a driven superconducting qubit coupled to a microwave resonator. Each signal photon deterministically induces a Raman transition in the Λ system and excites the qubit. The subsequent dispersive readout of the qubit produces a discrete ‘click'. We attain a high single-photon-detection efficiency of 0.66±0.06 with a low dark-count probability of 0.014±0.001 and a reset time of ∼400 ns. This detector can be exploited for various applications in quantum sensing, quantum communication and quantum information processing. PMID:27453153

  13. Conversion of fructose and glucose into 5-hydroxymethylfurfural with lignin-derived carbonaceous catalyst under microwave irradiation in dimethyl sulfoxide-ionic liquid mixtures.

    PubMed

    Guo, Feng; Fang, Zhen; Zhou, Tie-Jun

    2012-05-01

    5-Hydroxymethylfurfural (5-HMF) was successfully produced by the dehydration of fructose and glucose using lignin-derived solid acid catalyst in DMSO-[BMIM][Cl] (dimethyl sulfoxide and 1-butyl-3-methylimidazolium chloride) mixtures. Six solid acid catalysts were synthesized by carbonization and sulfonation of raw biomass materials, i.e., glucose, fructose, cellulose, lignin, bamboo and Jatropha hulls. It was found that lignin-derived solid acid catalyst (LCC) was the most active one in the dehydration of sugars. LCC coupled with microwave irradiation was used for the 5-HMF production, 84% 5-HMF yield with 98% fructose conversion rate was achieved at 110°C for 10 min. Furthermore, 99% glucose was converted with 68% 5-HMF yield under severer condition (160°C for 50 min). LCC was recycled for five times, 5-HMF yield declined only 7%. Use of LCC combined with DMSO-[BMIM][Cl] solution and microwave irradiation is a novel method for the effective production of 5-HMF. PMID:22429401

  14. Biodiesel production from lipids in wet microalgae with microwave irradiation and bio-crude production from algal residue through hydrothermal liquefaction.

    PubMed

    Cheng, Jun; Huang, Rui; Yu, Tao; Li, Tao; Zhou, Junhu; Cen, Kefa

    2014-01-01

    A cogeneration process of biodiesel and bio-crude was proposed to make full use of wet microalgae biomass. High-grade biodiesel was first produced from lipids in wet microalgae through extraction and transesterification with microwave irradiation. Then, low-grade bio-crude was produced from proteins and carbohydrates in the algal residue through hydrothermal liquefaction. The total yield (40.19%) and the total energy recovery (67.73%) of the cogenerated biodiesel and bio-crude were almost equal to those of the bio-oil obtained from raw microalgae through direct hydrothermal liquefaction. Upon microwave irradiation, proteins were partially hydrolyzed and the hydrolysates were apt for deaminization under the hydrothermal condition of the algal residue. Hence, the total remaining nitrogen (16.02%) in the cogenerated biodiesel and bio-crude was lower than that (27.06%) in the bio-oil. The cogeneration process prevented lipids and proteins from reacting to produce low-grade amides and other long-chain nitrogen compounds during the direct hydrothermal liquefaction of microalgae. PMID:24183493

  15. Nano-composite of poly(L-lactide) and halloysite nanotubes surface-grafted with L-lactide oligomer under microwave irradiation.

    PubMed

    Luo, Bing-Hong; Hsu, Chung-En; Li, Jian-Hua; Zhao, Liang-Feng; Liu, Ming-Xian; Wang, Xiao-Ying; Zhou, Chang-Ren

    2013-04-01

    In order to improve the bonding between halloysite nanotubes (HNTs) and poly(L-lactide) (PLLA), and hence to increase the mechanical properties of HNTs/PLLA nano-composite, HNTs were surface-grafted with PLLA under microwave irradiation and then blended with PLLA matrix. The optimal conditions for grafting polymerization are: irradiation time of 30 min, microwave power of 30 W and reaction temperature of 130 degrees C. The structure and properties of the surface-grafted HNTs (g-HNTs) were characterized by Fourier transformation infrared (FTIR), thermal gravimetric analysis (TGA), X-ray diffraction (XRD) and dynamic light scattering (DLS). Nano-composites of g-HNTs/PLLA and non-grafted HNTs/PLLA were subsequently evaluated in terms of crystallinity, dispersion, interfacial interaction, mechanical performance and cytocompatibility by polarized optical microscopy (POM), field scanning electron microscope (FESM), tensile testing and cell culture experiment. Results show that the grafted PLLA chains on the surfaces of HNTs, as inter-tying molecules, played an important role in improving the adhesive strength between the nanotubes and the polymer matrix. The enhanced interaction among g-HNTs and PLLA matrix resulted in a better tensile strength and modulus compared to the pristine PLLA and HNTs/PLLA. Cell culture results indicated that g-HNTs promoted both adhesion and proliferation of M3T3 fibroblasts on the g-HNTs/PLLA composite film. PMID:23621025

  16. Microwave heating for production of a glass bonded ceramic high-level waste form.

    SciTech Connect

    O'Holleran, T. P.

    2002-07-30

    Argonne National Laboratory has developed a ceramic waste form to immobilize the salt waste from electrometallurgical treatment of spent nuclear fuel. The process is being scaled up to produce bodies of 100 Kg or greater. With conventional heating, heat transfer through the starting powder mixture necessitates long process times. Coupling of 2.45 GHz radiation to the starting powders has been demonstrated. The radiation couples most strongly to the salt occluded zeolite powder. The results of these experiments suggest that this ceramic waste form could be produced using microwave heating alone, or by using microwave heating to augment conventional heating.

  17. Feasibility Study on a Microwave-Based Sensor for Measuring Hydration Level Using Human Skin Models

    PubMed Central

    Brendtke, Rico; Wiehl, Michael; Groeber, Florian; Schwarz, Thomas; Walles, Heike; Hansmann, Jan

    2016-01-01

    Tissue dehydration results in three major types of exsiccosis—hyper-, hypo-, or isonatraemia. All three types entail alterations of salt concentrations leading to impaired biochemical processes, and can finally cause severe morbidity. The aim of our study was to demonstrate the feasibility of a microwave-based sensor technology for the non-invasive measurement of the hydration status. Electromagnetic waves at high frequencies interact with molecules, especially water. Hence, if a sample contains free water molecules, this can be detected in a reflected microwave signal. To develop the sensor system, human three-dimensional skin equivalents were instituted as a standardized test platform mimicking reproducible exsiccosis scenarios. Therefore, skin equivalents with a specific hydration and density of matrix components were generated and microwave measurements were performed. Hydration-specific spectra allowed deriving the hydration state of the skin models. A further advantage of the skin equivalents was the characterization of the impact of distinct skin components on the measured signals to investigate mechanisms of signal generation. The results demonstrate the feasibility of a non-invasive microwave-based hydration sensor technology. The sensor bears potential to be integrated in a wearable medical device for personal health monitoring. PMID:27046226

  18. Feasibility Study on a Microwave-Based Sensor for Measuring Hydration Level Using Human Skin Models.

    PubMed

    Brendtke, Rico; Wiehl, Michael; Groeber, Florian; Schwarz, Thomas; Walles, Heike; Hansmann, Jan

    2016-01-01

    Tissue dehydration results in three major types of exsiccosis--hyper-, hypo-, or isonatraemia. All three types entail alterations of salt concentrations leading to impaired biochemical processes, and can finally cause severe morbidity. The aim of our study was to demonstrate the feasibility of a microwave-based sensor technology for the non-invasive measurement of the hydration status. Electromagnetic waves at high frequencies interact with molecules, especially water. Hence, if a sample contains free water molecules, this can be detected in a reflected microwave signal. To develop the sensor system, human three-dimensional skin equivalents were instituted as a standardized test platform mimicking reproducible exsiccosis scenarios. Therefore, skin equivalents with a specific hydration and density of matrix components were generated and microwave measurements were performed. Hydration-specific spectra allowed deriving the hydration state of the skin models. A further advantage of the skin equivalents was the characterization of the impact of distinct skin components on the measured signals to investigate mechanisms of signal generation. The results demonstrate the feasibility of a non-invasive microwave-based hydration sensor technology. The sensor bears potential to be integrated in a wearable medical device for personal health monitoring. PMID:27046226

  19. Variation in cyclic nucleotide levels and lysosomal enzyme activities in the irradiated rat

    SciTech Connect

    Trocha, P.J.; Catravas, G.N.

    1980-09-01

    Whole-body irradiation of rats causes not only a release of hydrolases from the lysosomes but also fluctuations in the cyclic nucleotide levels in spleen and liver tissues. Significant increases in lysosomal enzyme activities were further observed in spleen following radiation treatment. At 3 to 6 hr after rats were exposed to ..gamma.. radiation, transient increases in both cGMP and cAMP levels were accompanied with the release of ..beta..-glucuronidase and acid phosphatase enzymes from lysosomes in liver and spleen tissues. A second transitory release and activation of lysosomal hydrolases and an increase in cAMP levels occurred between 2 and 5 days after irradiation in spleen but not in liver. On Days 7 and 8, there was a third release of lysosomal hydrolases and a slight increase in the spleen cAMP concentration before they returned to near-control values. Cyclic GMP levels in the spleen decreased on the third day after irradiation, remained suppressed until Day 9, and then increased to levels higher than normal physiological values. The liver cGMP concentration remained unchanged between 9 hr and 11 days after irradiation.

  20. Color-Controlled Ag Nanoparticles and Nanorods within Confined Mesopores: Microwave-Assisted Rapid Synthesis and Application in Plasmonic Catalysis under Visible-Light Irradiation.

    PubMed

    Mori, Kohsuke; Verma, Priyanka; Hayashi, Ryunosuke; Fuku, Kojirou; Yamashita, Hiromi

    2015-08-10

    Color-controlled spherical Ag nanoparticles (NPs) and nanorods, with features that originate from their particle sizes and morphologies, can be synthesized within the mesoporous structure of SBA-15 by the rapid and uniform microwave (MW)-assisted alcohol reduction method in the absence or presence of surface-modifying organic ligands. The obtained several Ag catalysts exhibit different catalytic activities in the H2 production from ammonia borane (NH3 BH3 , AB) under dark conditions, and higher catalytic activity is observed by smaller yellow Ag NPs in spherical form. The catalytic activities are specifically enhanced under the light irradiation for all Ag catalysts. In particular, under light irradiation, the blue Ag nanorod shows a maximum enhancement of more than twice that observed in the dark. It should be noted that the order of increasing catalytic performance is in close agreement with the order of absorption intensity owing to the Ag localized surface plasmon resonance (LSPR) at irradiation light wavelength. Upon consideration of infrared thermal effect, wavelength dependence on catalytic activity, and effect of radical scavengers, it can be concluded that the dehydrogenation of AB is promoted by change of charge density of the Ag NP surface derived from LSPR. The LSPR-enhanced catalytic activity can be further realized in the tandem reaction consisting of dehydrogenation of AB and hydrogenation of 4-nitrophenol, in which a similar tendency in the enhancement of catalytic activity is observed. PMID:26178067

  1. Tandem Copper-Catalyzed Propargylation/Alkyne Azacyclization/Isomerization Reaction under Microwave Irradiation: Synthesis of Fully Substituted Pyrroles.

    PubMed

    Zhang, Xiao-Yan; Yang, Zhi-Wei; Chen, Zhongzhu; Wang, Jun; Yang, Dong-Lin; Shen, Ze; Hu, Li-Li; Xie, Jian-Wu; Zhang, Jin; Cui, Hai-Lei

    2016-03-01

    A copper-catalyzed and microwave-assisted synthesis of fully substituted pyrroles has been developed. A series of pentasubstituted pyrroles, especially α-arylpyrroles, could be obtained in moderate to good yields (up to 93%) through a tandem propargylation/alkyne azacyclization/isomerization sequence from readily available β-enamino compounds and propargyl acetates. PMID:26872395

  2. Monitoring PAI-1 and VEGF Levels in 6 Human Squamous Cell Carcinoma Xenografts During Fractionated Irradiation

    SciTech Connect

    Bayer, Christine; Kielow, Achim; Schilling, Daniela; Maftei, Constantin-Alin; Zips, Daniel; Yaromina, Ala; Baumann, Michael; Molls, Michael; Multhoff, Gabriele

    2012-11-01

    Purpose: Previous studies have shown that the plasminogen activator inhibitor type-1 (PAI-1) and vascular endothelial growth factor (VEGF) are regulated by hypoxia and irradiation and are involved in neoangiogenesis. The aim of this study was to determine in vivo whether changes in PAI-1 and VEGF during fractionated irradiation could predict for radiation resistance. Methods and Materials: Six xenografted tumor lines from human squamous cell carcinomas (HSCC) of the head and neck were irradiated with 0, 3, 5, 10, and 15 daily fractions of 2 Gy. The PAI-1 and VEGF antigen levels in tumor lysates were determined by enzyme-linked immunosorbent assay kits. The amounts of PAI-1 and VEGF were compared with the dose to cure 50% of tumors (TCD{sub 50}). Colocalization of PAI-1, pimonidazole (hypoxia), CD31 (endothelium), and Hoechst 33342 (perfusion) was examined by immunofluorescence. Results: Human PAI-1 and VEGF (hVEGF) expression levels were induced by fractionated irradiation in UT-SCC-15, UT-SCC-14, and UT-SCC-5 tumors, and mouse VEGF (msVEGF) was induced only in UT-SCC-5 tumors. High hVEGF levels were significantly associated with radiation sensitivity after 5 fractions (P=.021), and high msVEGF levels were significantly associated with radiation resistance after 10 fractions (P=.007). PAI-1 staining was observed in the extracellular matrix, the cytoplasm of fibroblast-like stroma cells, and individual tumor cells at all doses of irradiation. Colocalization studies showed PAI-1 staining close to microvessels. Conclusions: These results indicate that the concentration of tumor-specific and host-specific VEGF during fractionated irradiation could provide considerably divergent information for the outcome of radiation therapy.

  3. Microwave-assisted methanolysis of green coffee oil.

    PubMed

    Oigman, S S; de Souza, R O M A; Dos Santos Júnior, H M; Hovell, A M C; Hamerski, L; Rezende, C M

    2012-09-15

    Optimisation of a microwave-assisted methanolysis was performed to obtain cafestol and kahweol directly from green coffee oil (Coffea arabica). A two-factor (the methanolysis period and temperature), three-level, factorial experimental design (3(2)) was adopted. The methanolysis procedure was performed under microwave irradiation, using closed vessel and accurate fast responding internal fibre-optic temperature probe. The effects on the responses were measured by HPLC. After 3 min of microwave irradiation (hold time) at 100°C, with 500 mg of green coffee oil, a yield higher than 99% was obtained. The yield of this reaction is 26% after 2h when working under conventional heating. The methods described in the literature lead to long reaction times, poor yields and formation of side products. The microwave-assisted technique proved to be faster, avoided undesired side products and gave better conversion, when compared to conventional heating process. PMID:23107719

  4. Effects of intermittent flow and irradiance level on back reef Porites corals at elevated seawater temperatures

    USGS Publications Warehouse

    Smith, L.W.; Birkeland, C.

    2007-01-01

    Corals inhabiting shallow back reef habitats are often simultaneously exposed to elevated seawater temperatures and high irradiance levels, conditions known to cause coral bleaching. Water flow in many tropical back reef systems is tidally influenced, resulting in semi-diurnal or diurnal flow patterns. Controlled experiments were conducted to test effects of semi-diurnally intermittent water flow on photoinhibition and bleaching of the corals Porites lobata and P. cylindrica kept at elevated seawater temperatures and different irradiance levels. All coral colonies were collected from a shallow back reef pool on Ofu Island, American Samoa. In the high irradiance experiments, photoinhibition and bleaching were less for both species in the intermittent high-low flow treatment than in the constant low flow treatment. In the low irradiance experiments, there were no differences in photoinhibition or bleaching for either species between the flow treatments, despite continuously elevated seawater temperatures. These results suggest that intermittent flow associated with semi-diurnal tides, and low irradiances caused by turbidity or shading, may reduce photoinhibition and bleaching of back reef corals during warming events. ?? 2006 Elsevier B.V. All rights reserved.

  5. Identification of low level gamma-irradiation of meats by high sensitivity comet assay

    NASA Astrophysics Data System (ADS)

    Miyahara, Makoto; Saito, Akiko; Ito, Hitoshi; Toyoda, Masatake

    2002-03-01

    The detection of low levels of irradiation in meats (pork, beef, and chicken) using the new comet assay was investigated in order to assess the capability of the procedure. The new assay includes a process that improves its sensitivity to irradiation and a novel evaluation system for each slide (influence score and comet-type distribution). Samples used were purchased at retailers and were irradiated at 0.5 and 2kGy at 0°C. The samples were processed to obtain comets. Slides were evaluated by typing comets, calculating the influence score and analyzing the comet-type distribution chart of shown on the slide. Influence scores of beef, pork, and chicken at 0kGy were 287(SD=8.0), 305 (SD=12.9), and 320 (SD=21.0), respectively. Those at 500Gy, were 305 (SD=5.3), 347 (SD=10.6), and 364 (12.6), respectively. Irradiation levels in food were successfully determined. Sensitivity to irradiation differed among samples (chicken>pork>beef).

  6. Low-level He-Ne laser in intravascular irradiation treatment of schizophrenia

    NASA Astrophysics Data System (ADS)

    Zhou, Yu-Xue; Fu, Zheng-Hua

    1998-11-01

    Intravascular low level He-Ne laser irradiation is a new therapy developed in recent years. In our hospital it was applied in the treatment and observation of 220 cases of schizophrenia, among which certain effect was achieved and about which the detail was collated and elaborated.

  7. Research of epidermal cellular vegetal cycle of intravascular low level laser irradiation in treatment of psoriasis

    NASA Astrophysics Data System (ADS)

    Zhu, Jing; Bao, Xiaoqing; Zhang, Mei-Jue

    2005-07-01

    Objective: To research epidermal cellular vegetal cycle and the difference of DNA content between pre and post Intravascular Low Level Laser Irradiation treatment of psoriasis. Method: 15 patients suffered from psoriasis were treated by intravascular low level laser irradiation (output power: 4-5mw, 1 hour per day, a course of treatment is 10 days). We checked the different DNA content of epidermal cell between pre and post treatment of psoriasis and 8 natural human. Then the percentage of each phase among the whole cellular cycle was calculated and the statistical analysis was made. Results: The mean value of G1/S phase is obviously down while G2+M phase increased obviously. T test P<0.05.The related statistical analysis showed significant difference between pre and post treatments. Conclusions: The Intravascular Low Level Laser Irradiation (ILLLI) in treatment of psoriasis is effective according to the research of epidermal cellular vegetal cycle and the difference DNA content of Intravascular Low Level Laser Irradiation between pre and post treatment of psoriasis

  8. Differential effects of UV irradiation on nuclear retinoid receptor levels in cultured keratinocytes and melanocytes.

    PubMed

    Andersson, Eva; Rosdahl, Inger; Törmä, Hans; Vahlquist, Anders

    2003-10-01

    A major risk factor for skin cancer is UV irradiation, which not only damages DNA and other photosensitive compounds like vitamin A, but may also perturb cellular signaling, e.g. via the retinoid receptor system believed to be important for cancer protection. We used cultured normal human keratinocytes and melanocytes to examine the effects of UV irradiation on the expression of the predominant retinoid receptors in the human skin (RARalpha, RARgamma and RXRalpha) and the AP-1 protein c-Jun; mRNA levels were studied by real-time PCR and protein levels by Western blot. In keratinocytes, a single dose of UVB (50 mJ/cm2) caused a rapid drop in the expression of all three receptors (mRNA levels minus 35-50% after 4 h; protein levels minus 20-45% after 8 h), which was followed over the next 40 h by a variable response, leading to full normalization for RARalpha only. In contrast, the levels of c-Jun did not change significantly after UV exposure. In melanocytes, UVB caused a similar drop of the retinoid receptor levels as in keratinocytes but this was soon followed by an increased expression leading to a complete normalization of all receptor levels within 1-3 days. The c-Jun levels in melanocytes increased 1 day after UV exposure and remained high (plus 50%) thereafter. In both cell types, a approximately 3-fold increase in apoptosis (measured by DNA fragmentation) was observed 8-48 h after UVB irradiation. In conclusion, a depletion of vitamin A and retinoid receptors by UV irradiation, together with unchanged or even increased c-Jun levels, might seriously interfere with retinoid signaling and thus promote future tumor development, especially in keratinocytes. PMID:14705796

  9. Effects of Altered Levels of Extracellular Superoxide Dismutase and Irradiation on Hippocampal Neurogenesis in Female Mice

    SciTech Connect

    Zou, Yani; Leu, David; Chui, Jennifer; Fike, John R.; Huang, Ting-Ting

    2013-11-15

    Purpose: Altered levels of extracellular superoxide dismutase (EC-SOD) and cranial irradiation have been shown to affect hippocampal neurogenesis. However, previous studies were only conducted in male mice, and it was not clear if there was a difference between males and females. Therefore, female mice were studied and the results compared with those generated in male mice from an earlier study. Methods and Materials: Female wild-type, EC-SOD-null (KO), and EC-SOD bigenic mice with neuronal-specific expression of EC-SOD (OE) were subjected to a single dose of 5-Gy gamma rays to the head at 8 weeks of age. Progenitor cell proliferation, differentiation, and long-term survival of newborn neurons were determined. Results: Similar to results from male mice, EC-SOD deficiency and irradiation both resulted in significant reductions in mature newborn neurons in female mice. EC-SOD deficiency reduced long-term survival of newborn neurons whereas irradiation reduced progenitor cell proliferation. Overexpression of EC-SOD corrected the negative impacts from EC-SOD deficiency and irradiation and normalized the production of newborn neurons in OE mice. Expression of neurotrophic factors brain-derived neurotrophic factor and neurotrophin-3 were significantly reduced by irradiation in wild-type mice, but the levels were not changed in KO and OE mice even though both cohorts started out with a lower baseline level. Conclusion: In terms of hippocampal neurogenesis, EC-SOD deficiency and irradiation have the same overall effects in males and females at the age the studies were conducted.

  10. An Evaluation of Fracture Toughness of Vinyl Ester Composites Cured under Microwave Conditions

    NASA Astrophysics Data System (ADS)

    Ku, H.; Chan, W. L.; Trada, M.; Baddeley, D.

    2007-12-01

    under ambient conditions. Higher power microwaves, 540 and 720 W with shorter duration of exposure are used to cure the composites. Short-bar method of fracture toughness measurement was used to perform the tests. Plastic (PVC) re-usable molds were designed and manufactured for producing the test samples. The results show that the fracture toughness of specimens cured by microwave conditions are generally higher than those cured under ambient conditions, provided the power level and duration of microwave irradiation are properly and optimally selected.

  11. Prostate specific antigen levels after definitive irradiation for carcinoma of the prostate

    SciTech Connect

    Schellhammer, P.F.; Schlossberg, S.M.; el-Mahdi, A.M.; Wright, G.L.; Brassil, D.N. )

    1991-05-01

    Prostate specific antigen (PSA) levels were determined in 78 patients judged clinically to be free of disease at intervals of 36 or more months (range 38 to 186 months, median 87 months) after completion of irradiation therapy by 125-iodine implantation or external beam radiation. Of this select group of patients 38% had undetectable serum PSA levels (0.5 ng./ml. or less) and 38% had PSA levels that were within normal limits (4.0 ng./ml. or less). All stages and grades were represented. Undetectable PSA levels were only rarely found (3%) in patients with carcinoma of the prostate before treatment. In 24 of these 78 patients a negative biopsy of the irradiated prostate had been obtained 18 to 42 months after treatment. When the PSA level was drawn, which ranged from 7 to 16 years after treatment, an equal percentage of these biopsied patients had either an undetectable, normal or elevated level. Irradiation is able to decrease PSA to undetectable levels in some patients with prostatic carcinoma. Whether this reflects suppression of marker production alone or, more importantly, ablation of prostate cancer producing that marker remains to be determined.

  12. Elevation of blood levels of zinc protoporphyrin in mice following whole-body irradiation

    SciTech Connect

    Walden, T.L. Jr.

    1983-01-01

    Elevation of zinc protoporphyrin (ZPP) levels in the blood has served as an indicator of lead poisoning and iron deficiency anemia for many years. The author has discovered that sublethal doses of whole body irradiation with X-rays also elevates ZPP two- to three-fold over normal levels. The ZPP level does not begin to increase until days 12 to 14 post-irradiation and peaks between days 18 to 20 before returning to normal levels between days 28 to 35. Increasing the radiation dose delays the onset of the rise in ZPP but does not affect the magnitude of the elevation. At lethal doses, ZPP elevation is not observed. Neither of the two previously described mechanisms which cause elevations of ZPP, namely iron deficiency and inhibition of ferrochelatase, are responsible for the radiation induced elevation of ZPP. The elevation of ZPP appears to be correlated with the recovery of the hematopoietic system from radiation injury.

  13. Long-lived frequency shifts observed in a magnetic resonance force microscope experiment following microwave irradiation of a nitroxide spin probe

    SciTech Connect

    Chen, Lei; Longenecker, Jonilyn G.; Moore, Eric W.; Marohn, John A.

    2013-04-01

    We introduce a spin-modulation protocol for force-gradient detection of magnetic resonance that enables the real-time readout of longitudinal magnetization in an electron spin resonance experiment involving fast-relaxing spins. We applied this method to observe a prompt change in longitudinal magnetization following the microwave irradiation of a nitroxide-doped perdeuterated polystyrene film having an electron spin-lattice relaxation time of T{sub 1}{approx}1ms. The protocol allowed us to discover a large, long-lived cantilever frequency shift. Based on its magnitude, lifetime, and field dependence, we tentatively attribute this persistent signal to deuteron spin magnetization created via transfer of polarization from nitroxide spins.

  14. Generation of xylooligosaccharides from microwave irradiated agroresidues using recombinant thermo-alkali-stable endoxylanase of the polyextremophilic bacterium Bacillus halodurans expressed in Pichia pastoris.

    PubMed

    Kumar, Vikash; Satyanarayana, T

    2015-03-01

    The recombinant Pichia pastoris harboring the endoxylanase gene (TSEV1xyl) of Bacillus halodurans TSEV1 yielded a high titer of extracellular xylanase (502±23 U ml(-1)) on induction with methanol. The purified recombinant xylanase (TSEV1xyl) displayed optimal activity at 80°C and pH 9.0. The glycosylated recombinant xylanase exhibited higher thermostability (T1/2 of 45 min at 80°C) than the native enzyme (T1/2 of 35 min at 80°C). The agroresidues subjected to pretreatment (soaking in alkali followed by microwave irradiation) liberated xylooligosaccharides (XOS) upon hydrolysis with the recombinant xylanase. The removal of unhydrolyzed agroresidues, xylanase and xylose from the hydrolysate by two-step ultrafiltration led to the purification of XOS as confirmed by TLC as well as HPLC analysis. PMID:25553569

  15. Screening of lipases for the synthesis of xylitol monoesters by chemoenzymatic esterification and the potential of microwave and ultrasound irradiations to enhance the reaction rate.

    PubMed

    Rufino, Alessandra R; Biaggio, Francisco C; Santos, Julio C; de Castro, Heizir F

    2010-07-01

    Lipases from different sources, Pseudomonas fluorescens (AK lipase), Burkholderia cepacia (PS lipase), Penicillium camembertii (lipase G) and Porcine pancreas lipase (PPL), previously immobilized on epoxy SiO(2)-PVA, were screened for the synthesis of xylitol monoesters by esterification of the protected xylitol using oleic acid as acyl donor group. Among all immobilized derivatives, the highest esterification yield was achieved by P. camembertii lipase, showing to be attractive alternative to bulk chemical routes to satisfy increasing commercial demands. Further experiments were performed to determine the influence of fatty acids chain size on the reaction yield and the feasibility of using non-conventional heating systems (microwave and ultrasound irradiations) to enhance the reaction rate. PMID:20420851

  16. Direct preparation of Cu2ZnSnSe4 films by microwave irradiation and its dependence on the Sn/(Sn + Zn) ratio

    NASA Astrophysics Data System (ADS)

    Kaigawa, Ryuji; Hashimoto, Shintaro; Irago, Tomoki; Klenk, Reiner

    2015-08-01

    Cu2ZnSnSe4 (CZTSe) films with various Sn/(Sn + Zn) ratios were directly prepared on metallic Ti foils by microwave irradiation and their properties were investigated. The Sn/(Sn + Zn) ratio and Cu/(Sn + Zn) ratio of the precursor could be preserved by using a sealed container filled with 0.15 atm of Ar. Single-phase CZTSe crystals with a kesterite (stannite) structure and without by-products were observed with Sn/(Sn + Zn) ratios between 0.4 and 0.6. The hole densities of the Cu-Zn-Sn-Se films are minimal (<1017/cm3) with Sn/(Sn + Zn) ratios ranging from 0.5 to 0.6.

  17. Effect of different sulphur precursors on morphology and band-gap on the formation of Cu2ZnSnS4 (CZTS) particles with microwave irradiation

    NASA Astrophysics Data System (ADS)

    Patro, Bharati; Vijaylakshmi, S.; Sharma, Pratibha

    2016-05-01

    Cu2ZnSnS4 (CZTS) is a promising semiconductor material for ecological cost effective thin film Photovoltaic (PV) devices. As it contains earth abundant and non-toxic elements, it has the advantages over commercially available CIGS and CdTe thin film PV devices. In the present work, the pure phase Cu2ZnSnS4 particles were successfully synthesised with microwave irradiation. The morphology and phase study was carried out for the samples prepared with two different sulphur precursors viz. thiourea and thioacetamide (TAA). CZTS particles with thiourea as sulphur precursor are more crystalline than CZTS particles with TAA. The band gap of 1.654eV and 1.713eV were calculated for the samples prepared with thiourea and TAA respectively.

  18. Testing zinc chloride as a new catalyst for direct synthesis of cellulose di- and tri-acetate in a solvent free system under microwave irradiation.

    PubMed

    El Nemr, Ahmed; Ragab, Safaa; El Sikaily, Amany

    2016-10-20

    This research demonstrates the effect of ZnCl2 as a catalyst on the esterification of commercial cotton cellulose using acetic anhydride in order to obtain di- and tri-cellulose acetates under microwave irradiation. It was discovered that microwave irradiation significantly increased the yield and reduced the reaction time. It was found that the maximum yield for cellulose triacetates was 95.83% under the reaction conditions that were as follows: 3min reaction time, 200mg of ZnCl2 catalyst and 20ml of Ac2O for 5g cellulose. However, the cellulose acetate obtained in this manner had the highest DS (2.87). The cellulose di-acetate was produced with the maximum yield of 89.97% and with the highest DS (2.69) using 25ml Ac2O, 200mg of ZnCl2 for 5g cellulose and in 3min reaction time. The effect of some factors such as the amount of used catalyst, the quantity of acetic acid anhydride and the reaction time of the esterification process have been investigated. The production of di- and tri-cellulose acetate and the degree of substitution were confirmed using Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR). The thermal stability was investigated using thermo gravimetric analysis (TGA), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The molecular weight and the degree of polymerization were obtained using Gel Permeation Chromatography (GPC). The analysis confirmed the successful synthesis of di- and tri-cellulose acetate without degradation during the reaction; these results were found to be in contrast to some recent studies. The present study reveals that ZnCl2 is a new catalyst; it is effective as well as inexpensive and is a low toxicity catalyst for usage in cellulose esterification. PMID:27474655

  19. Polyacrylonitrile-based fiber modified with thiosemicarbazide by microwave irradiation and its adsorption behavior for Cd(II) and Pb(II).

    PubMed

    Deng, Sheng; Wang, Peng; Zhang, Guangshan; Dou, Yuan

    2016-04-15

    A novel thiosemicarbazide modified adsorbent (PAN(MW)-TSC) based on polyacrylonitrile fiber was successfully synthesized under microwave irradiation, which was applied for the uptake of Cd(II) and Pb(II) from aqueous solution subsequently. Microwave irradiation method is a new approach to achieve the modification and it turns out that just a 30min process is enough for the anchoring of functional groups in the fiber matrix. The surface characterization was performed by fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) elemental analysis (EA) and thermogravimetric analysis (TGA), indicating that the modification was successfully accomplished. Batch adsorption experiments including equilibrium isotherms, kinetics and the effects of pH and temperature on the adsorption of Cd(II) and Pb(II) were systematically studied. Among three kinetic models, the pseudo-second-order kinetic model provides the best correlation for the process. The nonlinear resolution of the Langmuir isotherm equation has been found to show the closest fit to the equilibrium date. Thermodynamic parameters, involving △G, △H and △S were also calculated from graphical interpretation of the experimental data, which suggest that metal ions adsorption onto PAN(MW)-TSC fibers is spontaneous and exothermic. Regeneration of PAN(MW)-TSC fibers loaded with metal ions was efficiently done with 0.5M HNO3, by which the investigated adsorbent could be used reproductively for five times with a small decrease in sorption capacity. The feasible preparation of PAN(MW)-TSC fibers with high adsorption capacities opens a new perspective in the potential application for wastewater treatment. PMID:26775107

  20. Low-level laser therapy on skeletal muscle inflammation: evaluation of irradiation parameters

    NASA Astrophysics Data System (ADS)

    Mantineo, Matías; Pinheiro, João P.; Morgado, António M.

    2014-09-01

    We evaluated the effect of different irradiation parameters in low-level laser therapy (LLLT) for treating inflammation induced in the gastrocnemius muscle of rats through cytokines concentration in systemic blood and analysis of muscle tissue. We used continuous (830 and 980 nm) and pulsed illuminations (830 nm). Animals were divided into five groups per wavelength (10, 20, 30, 40, and 50 mW), and a control group. LLLT was applied during 5 days with a constant irradiation time and area. TNF-α, IL-1β, IL-2, and IL-6 cytokines were quantified by ELISA. Inflammatory cells were counted using microscopy. Identical methodology was used with pulsed illumination. Average power (40 mW) and duty cycle were kept constant (80%) at five frequencies (5, 25, 50, 100, and 200 Hz). For continuous irradiation, treatment effects occurred for all doses, with a reduction of TNF-α, IL-1β, and IL-6 cytokines and inflammatory cells. Continuous irradiation at 830 nm was more effective, a result explained by the action spectrum of cytochrome c oxidase (CCO). Best results were obtained for 40 mW, with data suggesting a biphasic dose response. Pulsed wave irradiation was only effective for higher frequencies, a result that might be related to the rate constants of the CCO internal electron transfer process.

  1. Low-level Ga-Al-As laser irradiation enhances osteoblast proliferation through activation of Hedgehog signaling pathway

    NASA Astrophysics Data System (ADS)

    Li, Qiushi; Qu, Zhou; Chen, Yingxin; Liu, Shujie; Zhou, Yanmin

    2014-12-01

    Low-level laser irradiation has been reported to promote bone formation, but the molecular mechanism is still unclear. Hedgehog signaling pathway has been reported to play an important role in promoting bone formation. The aim of the present study was to examine whether low-level Ga-Al-As laser (808 nm) irradiation could have an effect on Hedgehog signaling pathway during osteoblast proliferation in vitro. Mouse osteoblastic cell line MC3T3-E1 was cultured in vitro. The cultures after laser irradiation (3.75J/cm2) were treated with recombinant N-terminals Sonic Hedgehog (N-Shh)or Hedgehog inhibitor cyclopamine (cy). The experiment was divided into 4 group, group 1:laser irradiation, group 2: laser irradiation and N-Shh, group 3: laser irradiation and cy, group 4:control with no laser irradiation. On day 1,2 and 3,cell proliferation was determined by cell counting, Cell Counting Kit-8.On 12 h and 24 h, cell cycle was detected by flow cytometry. Proliferation activity of laser irradiation and N-Shh group was remarkably increased compared with those of laser irradiation group. Proliferation activity of laser irradiation and cy group was remarkably decreased compared with those of laser irradiation group, however proliferation activity of laser irradiation and cy group was remarkably increased compared with those of control group. These results suggest that low-level Ga-Al-As laser irradiation activate Hedgehog signaling pathway during osteoblast proliferation in vitro. Hedgehog signaling pathway is one of the signaling pathways by which low-level Ga-Al-As laser irradiation regulates osteoblast proliferation.

  2. Calorimetry study of microwave absorption of some solid materials.

    PubMed

    He, Chun Lin; Ma, Shao Jian; Su, Xiu Juan; Chen, Yan Qing; Liang, Yu Shi

    2013-01-01

    In practice, the dielectric constant of a material varies the applied frequency the material composition, particle size, purity, temperature, physical state (solid or liquid), and moisture content. All of these parameters might change during processing, therefore, it is difficult to predict how well a material will absorb microwave energy in a given process. When the temperature is measured by a digital thermometer, it could not accurately reflect the true temperature of the bulk materials, especially for mixed materials. Thus, in this paper we measured the microwave absorption characteristics of different materials by calorimetry. The microwave power levels, irradiation times, and masses of the materials were varied. It was difficult to predict the microwave energy absorption characteristics of reagent-grade inorganic compounds based on their color, metallic cation, or water stoichiometry. CuO, MnO2, Fe3O4, and MnSO4 x H2O (Taishan) strongly absorbed microwave energy. Most of the remaining inorganic compounds were poor absorbers, with silica hardly absorbing any microwave energy. Carbon-based materials had significantly different microwave absorption characteristics. Activated carbon and coke were especially sensitive to microwaves, but different types of coal were poor absorbers. The jamesonite concentrate absorbed microwave energy strongly, while the zinc concentrate was a poor absorber. PMID:24779227

  3. Microwave studies of collision-induced transitions between rotational levels. VIII. Collisions between NH/sub 3/ and polar molecules

    SciTech Connect

    Fabris, A.R.; Oka, T.

    1983-03-15

    The technique of four-level microwave double resonance has been applied to the study of rotation-inversion transitions of NH/sub 3/ induced by collisions with various polar molecules. H/sub 2/O, D/sub 2/O, CH/sub 3/OH, CH/sub 3/X and CHX/sub 3/ (X = F, Cl, Br, I), NO, CO, and OCS were used as collision partners. The values of eta = ..delta..I/I observed for many four-level systems which are connected by dipole-type transitions (..delta..J = +- 1, ..delta..K = 0, parity +bold-arrow-left-right-) are given and qualitatively explained taking into account the long-range dipole--dipole interaction and the pattern of rotational energy levels of the collision partners.

  4. High-resolution tri-level process by downstream-microwave rf-biased etching

    NASA Astrophysics Data System (ADS)

    Rangelow, Ivo W.

    1991-03-01

    In this paper we discuss some properties of a novel dry etching system for high resolution transfer of e-beam generated pattern for a viable submicron lithography. In order to achieve pattern transfer by an e-beam lithography a tn-layer system has been used. The submicron pattern which has been generated in a 300 nm PBS-layer (imaging layer) was transfered into a 300 nm anorganic intermediate layer (Si3N4) by RIE with a CHF3-plasma. The underlayer of 1 micron polyimid was etched in a microwave downstream RF-biased etching system developed by Plasma Technology Ltd (UK). E-beam lithography generated structures of 75 nm size with very low image size bias were etched in Si3N4. After patterning in the polyimid layer structures with very high aspect ratio (10) could be achieved. It was observed that anisotropy is enhanced by crack-products that originate from the microwave downstream oxygen plasma and the CHF3+CH4 mixture in the space between the parallel-plate electrodes.

  5. Therapeutic and diagnostic set for irradiation the cell lines in low level laser therapy

    NASA Astrophysics Data System (ADS)

    Gryko, Lukasz; Zajac, Andrzej; Gilewski, Marian; Szymanska, Justyna; Goralczyk, Krzysztof

    2014-05-01

    In the paper is presented optoelectronic diagnostic set for standardization the biostimulation procedures performed on cell lines. The basic functional components of the therapeutic set are two digitally controlled illuminators. They are composed of the sets of semiconductor emitters - medium power laser diodes and high power LEDs emitting radiation in wide spectral range from 600 nm to 1000 nm. Emitters are coupled with applicator by fibre optic and optical systems that provides uniform irradiation of vessel with cell culture samples. Integrated spectrometer and optical power meter allow to control the energy and spectral parameters of electromagnetic radiation during the Low Level Light Therapy procedure. Dedicated power supplies and digital controlling system allow independent power of each emitter . It was developed active temperature stabilization system to thermal adjust spectral line of emitted radiation to more efficient association with absorption spectra of biological acceptors. Using the set to controlled irradiation and allowing to measure absorption spectrum of biological medium it is possible to carry out objective assessment the impact of the exposure parameters on the state cells subjected to Low Level Light Therapy. That procedure allows comparing the biological response of cell lines after irradiation with radiation of variable spectral and energetic parameters. Researches were carried out on vascular endothelial cell lines. Cells proliferations after irradiation of LEDs: 645 nm, 680 nm, 740 nm, 780 nm, 830 nm, 870 nm, 890 nm, 970 nm and lasers 650 nm and 830 nm were examined.

  6. Spectral shape deformation in inverse spin Hall voltage in Y{sub 3}Fe{sub 5}O{sub 12}|Pt bilayers at high microwave power levels

    SciTech Connect

    Lustikova, J. Shiomi, Y.; Handa, Y.; Saitoh, E.

    2015-02-21

    We report on the deformation of microwave absorption spectra and of the inverse spin Hall voltage signals in thin film bilayers of yttrium iron garnet (YIG) and platinum at high microwave power levels in a 9.45-GHz TE{sub 011} cavity. As the microwave power increases from 0.15 to 200 mW, the resonance field shifts to higher values, and the initially Lorentzian spectra of the microwave absorption intensity as well as the inverse spin Hall voltage signals become asymmetric. The contributions from opening of the magnetization precession cone and heating of YIG cannot well reproduce the data. Control measurements of inverse spin Hall voltages on thin-film YIG|Pt systems with a range of line widths underscore the role of spin-wave excitations in spectral deformation.

  7. Rapid synthesis of flower-like Cu2O architectures in ionic liquids by the assistance of microwave irradiation with high photochemical activity.

    PubMed

    Li, Shi-Kuo; Guo, Xuan; Wang, Yang; Huang, Fang-Zhi; Shen, Yu-Hua; Wang, Xue-Mei; Xie, An-Jian

    2011-07-01

    A novel and facile protocol for the rapid synthesis of flower-like Cu(2)O architectures is reported in the presence of ionic liquid 1-n-butyl-3-methyl imidazolium tetrafluoroborate ([BMIM]BF(4)) with the assistance of microwave irradiation. The hierarchical structures are assembled from many thin nanosheets with tunable sizes by adjusting the amount of [BMIM]BF(4) in the reaction solution. Noticeably, the flower-like Cu(2)O architectures present a high surface area of 65.77 cm(2) g(-1) with a band gap of about 2.25 eV, and exhibit high and stable photochemical activity for the reduction of Cr(VI) to Cr(III) under visible light irradiation. A reasonable model of an absorption and diffusion-limited aggregation process is proposed for explaining the possible formation mechanism of the flower-like Cu(2)O. The approach described in this study provides a feasible and rapid method to synthesize flower-like Cu(2)O with a hierarchical structure that is ready for application in the fields of photocatalytic hazard pollutants. PMID:21625672

  8. Impact of proton irradiation on deep level states in n-GaN

    SciTech Connect

    Zhang, Z.; Arehart, A. R.; Cinkilic, E.; Ringel, S. A.; Chen, J.; Zhang, E. X.; Fleetwood, D. M.; Schrimpf, R. D.; McSkimming, B.; Speck, J. S.

    2013-07-22

    Deep levels in 1.8 MeV proton irradiated n-type GaN were systematically characterized using deep level transient spectroscopies and deep level optical spectroscopies. The impacts of proton irradiation on the introduction and evolution of those deep states were revealed as a function of proton fluences up to 1.1 × 10{sup 13} cm{sup −2}. The proton irradiation introduced two traps with activation energies of E{sub C} - 0.13 eV and 0.16 eV, and a monotonic increase in the concentration for most of the pre-existing traps, though the increase rates were different for each trap, suggesting different physical sources and/or configurations for these states. Through lighted capacitance voltage measurements, the deep levels at E{sub C} - 1.25 eV, 2.50 eV, and 3.25 eV were identified as being the source of systematic carrier removal in proton-damaged n-GaN as a function of proton fluence.

  9. Effects of low-level chronic irradiation on radiosensitivity of mammals: modeling and experimental studies

    NASA Astrophysics Data System (ADS)

    Smirnova, O. A.; Yonezawa, M.

    Effects of low dose rate chronic irradiation on radiosensitivity of mammals mice are studied by experimental and modeling methods Own and reference experiments show that priming chronic low-level short-term and long-term exposures to radiation induce respectively elevated radiosensitivity and lowered radiosensitivity radioresistance in mice The manifestation of these radiosensitization and radioprotection effects are respectively increased and decreased mortality of preirradiated specimens after challenge acute irradiation in comparison with those for previously unexposed ones Taking into account that the reason of the animal death in the experiments was the hematopoietic syndrome the biophysical models of the critical body system hematopoiesis are used to simulate the dynamics of the major hematopoietic lines in mice exposed to challenge acute irradiation following the chronic one Juxtaposition of the modeling results obtained and the relevant experimental data shows that the radiosensitization effect of chronic low-level short-term less than 1 month preirradiation on mice is due to increased radiosensitivity of lymphopoietic granulocytopoietic and erythropoietic systems accompanied by increased or close to the normal level radiosensitivity of thrombocytopoietic system which are induced by the above-indicated exposure In turn the radioprotection effect of chronic low-level long-term more than 1 month preirradiation on mice is caused by decreased radiosensitivity radioresistance of the granulocytopoietic system which

  10. Molten salt-supported polycondensation of optically active diacid monomers with an aromatic thiazole-bearing diamine using microwave irradiation

    PubMed Central

    Mallakpour, Shadpour; Zadehnazari, Amin

    2013-01-01

    Microwave heating was used to prepare optically active thiazole-bearing poly(amide-imide)s. Polymerization reactions were carried out in the molten tetrabutylammonium bromide as a green molten salt medium and triphenyl phosphite as the homogenizer. Structural elucidation of the compounds was performed by Fourier transform infrared and NMR spectroscopic data and elemental analysis results. The polymeric samples were readily soluble in various organic solvents, forming low-colored and flexible thin films via solution casting. They showed high thermal stability with decomposition temperature being above 360 °C. They were assembled randomly in a nanoscale size. PMID:25685498