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Sample records for microwave digestion procedures

  1. Rapid Microwave Digestion Procedures for the Elemental Analysis of Alloy and Slag Samples of Smelted Ocean Bed Polymetallic Nodules

    Directory of Open Access Journals (Sweden)

    Kumari Smita

    2013-01-01

    Full Text Available The use of microwave digester for digestion of alloy and slag samples of smelted ocean bed polymetallic nodules has permitted the complete digestion of samples, thereby replacing the tedious classical methods of digestion of samples. The digestion procedure includes two acid-closed digestions of samples in a microwave oven. Owing to the hazardous nature of perchloric acid, it was not used in developed digestion procedure. Digested sample solutions were analyzed for concentrations of various radicals and the effectiveness of the developed digestion methodology was tested using certified reference materials. It was found that the developed method is giving results comparable with that obtained from conventionally digested samples. In this digestion procedure, time required for digestion of samples was reduced to about 1 hour only from 8-9 hours of conventional digestion.

  2. A simultaneous, direct microwave/ultrasound-assisted digestion procedure for the determination of total Kjeldahl nitrogen.

    Science.gov (United States)

    Domini, Claudia; Vidal, Lorena; Cravotto, Giancarlo; Canals, Antonio

    2009-04-01

    Simultaneous direct irradiation with microwaves and ultrasound was used to determine total Kjeldahl nitrogen. The method involves chemical digestion in two steps, mineralization with sulfuric acid and oxidation with H(2)O(2). The most influential variables for the microwave/ultrasound (MW/US)-assisted digestion were optimized using tryptophan as the model substance. The optimum conditions were: H(2)SO(4) volume, 10 mL; H(2)O(2) volume, 5 mL; weight of sample, 0.05 g; MW power, 500 W; US power, 50 W; digestion time, 7 min (i.e., 5 min mineralization and 2 min oxidation). A modification of the classical Kjeldahl (Hach) method and an US-assisted digestion method were used for comparison. The latter was also optimized; the optimum conditions were: H(2)SO(4) volume, 10 mL; H(2)O(2) volume, 5 mL; sonication time with H(2)SO(4), 15 min; sonication time with H(2)O(2),10 min; US power, 50 W; weight of sample, 0.05 g. Five pure amino acids and two certified reference materials (NIST standard reference materials 1547 (peach leaves), and soil, NCS DC 73322) were analyzed to assess the accuracy of our new MW/US-assisted digestion method, that was successfully applied to five real samples. The significant reduction in digestion time (being 30 min and 25 min for classical Kjeldahl and US-assisted digestion methods, respectively) and consumption of reagents show that simultaneous and direct MW/US irradiation is a powerful and promising tool for low-pressure digestion of solid and liquid samples.

  3. Optimization of microwave assisted digestion procedure for the determination of zinc, copper and nickel in tea samples employing flame atomic absorption spectrometry.

    Science.gov (United States)

    Soylak, Mustafa; Tuzen, Mustafa; Souza, Anderson Santos; das Graças Andrade Korn, Maria; Ferreira, Sérgio Luis Costa

    2007-10-22

    The present paper describes the development of a microwave assisted digestion procedure for the determination of zinc, copper and nickel in tea samples employing flame atomic absorption spectrometry (FAAS). The optimization step was performed using a full factorial design (2(3)) involving the factors: composition of the acid mixture (CMA), microwave power (MP) and radiation time (RT). The experiments of this factorial were carried out using a certified reference material of tea GBW 07605 furnished by National Research Centre for Certified Reference Materials, China, being the metal recoveries considered as response. The relative standard deviations of the method were found below 8% for the three elements. The procedure proposed was used for the determination of copper, zinc and nickel in several samples of tea from Turkey. For 10 tea samples analyzed, the concentration achieved for copper, zinc and nickel varied at 6.4-13.1, 7.0-16.5 and 3.1-5.7 (microg g(-1)), respectively.

  4. Optimization of an open-focused microwave oven digestion procedure for determination of metals in diesel oil by inductively coupled plasma optical emission spectrometry.

    Science.gov (United States)

    Sant'Ana, Flavio W; Santelli, Ricardo E; Cassella, Alessandra R; Cassella, Ricardo J

    2007-10-01

    This work reports the optimization of a focused microwave assisted procedure for the wet acid dissolution of diesel oil in order to allow the determination of metals in the samples by inductively coupled plasma optical emission spectrometry (ICP-OES). The dissolution process was monitored by measuring residual carbon content (RCC), also by ICP-OES, in the final solutions obtained after application of digestion program. All experimental work was performed using a commercial sample of diesel oil containing 85.74+/-0.13% of carbon. The initial dissolution program comprised three steps: (i) carbonization with H(2)SO(4); (ii) oxidation with HNO(3) and (iii) final oxidation with H(2)O(2). During work it was verified that the first step played an important role on the dissolution process of this kind of sample. It is therefore, necessary to give a detailed optimization of such step. Employing the optimized conditions it was possible to digest 2.5 g of diesel oil with a 40 min-heating program. At these conditions, residual carbon content was always lower than 5%. Optimized methodology was applied in the determination of metals in three diesel oil samples by ICP-OES. Recovery tests were also performed by adding 10 microg of metals, as organic standards, to the samples before digestion. Recovery percentages always higher than 90% were obtained for the metals of interest (Al, Cu, Fe and Ni), except for Zn, which presented recoveries between 70 and 78%.

  5. Improved microwave-assisted wet digestion procedures for accurate Se determination in fish and shellfish by flow injection-hydride generation-atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Lavilla, I. [Departamento de Quimica Analitica y Alimentaria, Area de Quimica Analitica, Universidad de Vigo, Facultad de Ciencias (Quimica), As Lagoas - Marcosende s/n, 36310 Vigo (Spain); Gonzalez-Costas, J.M. [Departamento de Quimica Analitica y Alimentaria, Area de Quimica Analitica, Universidad de Vigo, Facultad de Ciencias (Quimica), As Lagoas - Marcosende s/n, 36310 Vigo (Spain); Bendicho, C. [Departamento de Quimica Analitica y Alimentaria, Area de Quimica Analitica, Universidad de Vigo, Facultad de Ciencias (Quimica), As Lagoas - Marcosende s/n, 36310 Vigo (Spain)]. E-mail: bendicho@uvigo.es

    2007-05-22

    Accurate determination of Se in biological samples, especially fish and shellfish, by hydride generation techniques has generally proven troublesome owing to the presence of organoselenium that cannot readily converted into inorganic selenium under usual oxidising conditions. Further improvements in the oxidation procedures are needed so as to obtain accurate concentration values when this type of samples is analyzed. Microwave-assisted wet digestion (MAWD) procedures of seafood based on HNO{sub 3} or the mixture HNO{sub 3}/H{sub 2}O{sub 2} and further thermal reduction of the Se(VI) formed to Se(IV) were evaluated. These procedures were as follows: (I) without H{sub 2}O{sub 2} and without heating to dryness; (II) without H{sub 2}O{sub 2} and with heating to dryness; (III) with H{sub 2}O{sub 2} and without heating to dryness; (IV) with H{sub 2}O{sub 2} and with heating to dryness. In general, low recoveries of selenium are obtained for several marine species (e.g., crustaceans and cephalopods), which may be ascribed to the presence of Se forms mainly associated with nonpolar proteins and lipids. Post-digestion UV irradiation proved very efficient since not only complete organoselenium decomposition was achieved but also the final step required for prereduction of Se(VI) into Se(IV) (i.e. heating at 90 deg. C for 30 min in 6 M HCl) could be avoided. With the MAWD/UV procedure, the use of strong oxidising agents (persuphate, etc.) or acids (e.g. perchloric acid) which are typically applied prior to Se determination by hydride generation techniques is overcome, and as a result, sample pre-treatment is significantly simplified. The method was successfully validated against CRM DOLT-2 (dogfish liver), CRM DORM-2 (dogfish muscle) and CRM TORT-2 (lobster hepatopancreas). Automated ultrasonic slurry sampling with electrothermal atomic absorption spectrometry was also applied for comparison. Total Se contents in ten seafood samples were established. Se levels ranged from 0

  6. Literature study of microwave-assisted digestion using electrothermal atomic absorption spectrometry.

    Science.gov (United States)

    Chakraborty, R; Das, A K; Cervera, M L; De La Guardia, M

    1996-05-01

    The literature on the use of microwave-assisted digestion procedures for subsequent sample analysis by means of electrothermal atomic absorption spectrometry (ETAAS) is reviewed. The literature survey reveals that this digestion technique has been applied mainly for biological materials. The elements most extensively determined by this method are cadmium and lead followed by copper, chromium, nickel and iron. The microwave digestion conditions, ETAAS furnace programmes and analytical details of the developed methodologies have been carefully revised.

  7. Rapid determination of total Kjeldahl nitrogen using microwave digestion.

    Science.gov (United States)

    Lo, K V; Wong, W T; Liao, P H

    2005-01-01

    A closed-vessel microwave digestion process for the determination of total Kjeldahl nitrogen (TKN) has been developed for sewage and wastewater. TKN values obtained from the microwave digestion method were in excellent agreement with those of the thermal digestion method. The accuracy of both analytical methods is comparable. In comparison to the conventional thermal digestion, the microwave method shortened the time required for complete digestion from 4 h to 25 min, and also decreased the maximum digestion temperature from 380 degrees C to 200 degrees C. This developed method may contribute to a significant reduction in sample digestion time, resulting in an increase in analytical throughput. The microwave digestion method developed in this study could be a rapid and efficient means for TKN determination for sewage wastewater and sludge.

  8. Comparison of three optimized digestion methods for rapid determination of chemical oxygen demand: Closed microwaves, open microwaves and ultrasound irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Domini, Claudia E. [Departamento de Quimica, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina); Hidalgo, Montserrat [Departamento de Quimica Analitica, Nutricion y Bromatologia, Universidad de Alicante, Apdo. 99, 03080 Alicante (Spain); Marken, Frank [Department of Chemistry, University of Bath, Bath BA2 7AY (United Kingdom); Canals, Antonio [Departamento de Quimica Analitica, Nutricion y Bromatologia, Universidad de Alicante, Apdo. 99, 03080 Alicante (Spain)]. E-mail: a.canals@ua.es

    2006-03-02

    In the present work, experimental design was used for the fast optimization of three kinds of sample digestion procedures with the final aim of obtaining the COD value of wastewater samples. The digestion methods evaluated were 'closed microwave-assisted' (CMWD), 'open microwave-assisted' (OMWD) and 'ultrasound-assisted' (USD). Classical digestion was used as reference method. The optimum values for the different variables studied in each method were: 90 psi pressure, 475 W power and 4 min irradiation time (CMWD); 150 deg. C temperature and 4 min irradiation time (OMWD); 90% of maximum nominal power (180 W), 0.9 s (s{sup -1}) cycles and 1 min irradiation time (USD). In all cases, interference concentration that produces a deviation of 10% in COD values is 13.4, 23.4, 21.1 and 2819 mg/L for S{sup 2-}, Fe{sup 2+}, NO{sub 2} {sup -} and Cl{sup -}, respectively. Under optimum conditions, the proposed digestion methods have been successfully applied, with the exception of pyridine, to several pure organic compounds and COD recoveries for 10 real wastewater samples were ranged between 88 and 104% of the values obtained with the classical (open reflux) method used as reference, with R.S.D. lower than 4% in most cases. Thus, the use of ultrasound energy for COD determination seems to be an interesting and promising alternative to conventional open reflux and microwave-assisted digestion methods used for the same purpose since the instrumentation is simpler, cheaper and safer and the digestion step faster than the ones used for the same purpose.

  9. Biogas recovery from microwave heated sludge by anaerobic digestion

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Biogas generated from sewage sludge,livestock waste,and food waste by anaerobic digestion is a valuable renewable energy resource.However,conventional anaerobic digestion is not an efficient process.A long hydraulic retention time and low biogas recovery rate hinder the applications of those resources.An effective pretreatment method to destroy sludge microbial cells has been one of the major concerns regarding improvement of the biogas production.This article focuses on the effects of microwave heating on sludge anaerobic digestion.Volatile suspended solid(VSS) and chemical organic demand solubilization of heated sludge were investigated.Microwave heating was found to be a rapid and efficient process for releasing organic substrates from sludge.The increase of organic dissolution ratio was not obvious when holding time was over 5 min with microwave heating.The effect of the VSS solubilization was primarily dependent on heating temperature.The highest value of VSS dissolving ratio,36.4%,was obtained at 170°C for 30 min.The COD dissolving ratio was about 25% at 170°C.Total organic carbon of treated sludge liquor was 1.98 and 2.73 g/L at 150°C and 170°C for 5 min,respectively.A biochemical methane potential(BMP) test of excess sludge and a mixture of primary and excess sludge demonstrated an increase in biogas production.The total biogas from microwave treated mixture sludge increased by 12.9% to 20.2% over control after 30 days of digestion.Biogas production was 11.1% to 25.9% higher for excess sludge than for untreated sludge.The VS removal ratios of mixture sludge and excess sludge were 12% and 11% higher,respectively,compared to the untreated sludge.

  10. Studying the effect of microwave heating on the digestion process and identification of proteins.

    Science.gov (United States)

    Devi, Shobha; Wu, Bo-Hung; Chu, Pei-Yu; Liu, Yue-Pei; Wu, Hsin-Lin; Ho, Yen-Peng

    2017-02-01

    The impact of microwave irradiation on the in-solution digestion processes and the detection limit of proteins are systematically studied. Kinetic processes of many peptides produced through the trypsin digestion of various proteins under microwave heating at 50°C were investigated with MALDI-MS. This study also examines the detection limits and digestion completeness of individual proteins under microwave heating at 50°C and at different time intervals (1, 5 and 30 min) using LC-MS. We conclude that if the peptides without missed cleavage dictate the detection limit, conventional digestion will lead to a better detection limit. The detection limit may not differ between the microwave and conventional heating if the peptides with missed cleavage sites and strong intensity are formed at the very early stage (i.e., less than 1 min) and are not further digested throughout the entire digestion process. The digestion of Escherichia coli lysate was compared under conventional and short time (microwave) conditions. The number of proteins identified under conventional heating exceeded that obtained from microwave heating over heating periods less than 5 min. The overall results show that the microwave-assisted digestion is not complete. Although the sequence coverage might be better, the detection limit might be worse than that under conventional heating. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Determination of toxic elements in coal by ICP-MS after digestion using microwave-induced combustion.

    Science.gov (United States)

    Antes, Fabiane G; Duarte, Fábio A; Mesko, Márcia F; Nunes, Matheus A G; Pereira, Vanda A; Müller, Edson I; Dressler, Valderi L; Flores, Erico M M

    2010-12-15

    A microwave-induced combustion (MIC) procedure was applied for coal digestion for subsequent determination of As, Cd and Pb by inductively coupled plasma mass spectrometry (ICP-MS) and Hg using cold vapor (CV) generation coupled to ICP-MS. Pellets of coal (500 mg) were combusted using 20 bar of oxygen and ammonium nitrate as aid for ignition. The use of nitric acid as absorbing solution (1.7, 3.5, 5.0, 7.0 and 14 mol L(-1)) was evaluated. For coal samples with higher ash content, better results were found using 7.0 mol L(-1) HNO(3) and an additional reflux step of 5 min after combustion step. For coal samples with ash content lower than 8%, 5.0 mol L(-1) nitric acid was suitable to the absorption of all analytes. Accuracy was evaluated using certified reference material (CRM) of coal and spikes. Agreement with certified values and recoveries was better than 95 and 97%, respectively, for all the analytes. For comparison of results, a procedure recommended by the American Society of Testing and Materials (ASTM) was used. Additionally, a conventional microwave-assisted digestion (MAD) in pressurized vessels was also performed. Using ASTM procedure, analyte losses were observed and a relatively long time was necessary for digestion (>6h). By comparison with MAD procedure, higher sample mass can be digested using MIC allowing better limits of detection. Additionally, the use of concentrated acids was not necessary that is an important aspect in order to obtain low blank levels and lower limits of detection, respectively. The residual carbon content in digests obtained by MAD and MIC was about 15% and <1%, respectively, showing the better digestion efficiency of MIC procedure. Using MIC it was possible to digest completely and simultaneously up to eight samples in only 25 min with relatively lower generation of laboratory effluents.

  12. [Determination of trace lead in traditional Chinese herbal medicine Astragalus by microwave digestion-CTAB enhancing-continual flow ingection hydride generation-ICP-AES].

    Science.gov (United States)

    Liu, Dong-Lian; Ke, Shao-Ying; Ye, Rong; Ding, Ming-Yu

    2007-11-01

    A new method using microwave digestion technique was developed for the determination of lead in Astragalus by CTAB enhancing-continual flow hydride generation-inductively coupled plasma atomic emission spectrometry (HG-ICP-AES). The experimental conditions of microwave digestion and hydride generation were optimized. This method shows a linear range of 0.23-800 microg x L(-1) and the correlation coefficient is 0.999 9. It is satisfactory to apply the microwave digestion procedure to the determination of Pb under the optimized conditions. The detection limit of the method is 0.23 microg x L(-1) and the RSD is 1.02%. The recovery obtained is 98.8%-100.1%. The results show that this method is rapid and simple with low environmental contamination and complete digestion of samples.

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

    Science.gov (United States)

    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.

  14. Partial microwave-assisted wet digestion of animal tissue using a baby-bottle sterilizer for analyte determination by inductively coupled plasma optical emission spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Matos, Wladiana O. [Grupo de Analise Instrumental Aplicada, Universidade Federal de Sao Carlos, Sao Carlos SP (Brazil); Grupo de Analise Instrumental Aplicada, Embrapa Pecuaria Sudeste, Sao Carlos, SP (Brazil)], E-mail: wladianamatos@yahoo.com.br; Menezes, Eveline A. [Grupo de Analise Instrumental Aplicada, Universidade Federal de Sao Carlos, Sao Carlos SP (Brazil); Grupo de Analise Instrumental Aplicada, Embrapa Pecuaria Sudeste, Sao Carlos, SP (Brazil); Gonzalez, Mario H. [Grupo de Analise Instrumental Aplicada, Universidade Federal de Sao Carlos, Sao Carlos SP (Brazil); Costa, Leticia M. [Departamento de Quimica-ICEx, Universidade Federal de Minas Gerais, Belo Horizonte MG (Brazil); Trevizan, Lilian C. [Centro de Energia Nuclear na Agricultura, Universidade de Sao Paulo, Piracicaba SP (Brazil); Nogueira, Ana Rita A. [Grupo de Analise Instrumental Aplicada, Embrapa Pecuaria Sudeste, Sao Carlos, SP (Brazil)

    2009-06-15

    A procedure for partial digestion of bovine tissue is proposed using polytetrafluoroethylene (PTFE) micro-vessels inside a baby-bottle sterilizer under microwave radiation for multi-element determination by inductively coupled plasma optical emission spectrometry (ICP OES). Samples were directly weighed in laboratory-made polytetrafluoroethylene vessels. Nitric acid and hydrogen peroxide were added to the uncovered vessels, which were positioned inside the baby-bottle sterilizer, containing 500 mL of water. The hydrogen peroxide volume was fixed at 100 {mu}L. The system was placed in a domestic microwave oven and partial digestion was carried out for the determination of Ca, Cu, Fe, Mg, Mn and Zn by inductively coupled plasma optical emission spectrometry. The single-vessel approach was used in the entire procedure, to minimize contamination in trace analysis. Better recoveries and lower residual carbon content (RCC) levels were obtained under the conditions established through a 2{sup 4-1} fractional factorial design: 650 W microwave power, 7 min digestion time, 50 {mu}L nitric acid and 50 mg sample mass. The digestion efficiency was ascertained according to the residual carbon content determined by inductively coupled plasma optical emission spectrometry. The accuracy of the proposed procedure was checked against two certified reference materials.

  15. Is microwave digestion using TFM vessels a suitable preparation method for Pt determination in biological samples by adsorptive cathodic stripping voltammetry?

    Science.gov (United States)

    Haus, Nadine; Eybe, Tanja; Zimmermann, Sonja; Sures, Bernd

    2009-03-02

    The occurrence of Pt in environmental matrices is increasing since the introduction of automobile catalytic converters. Given that Pt is bioavailable and causes biological effects in plants and animals, respective biomonitoring programs are in high demand. But the analytical methods for conducting such programs have not yet been sufficiently established. Therefore, a study was carried out to develop a microwave digestion of biological samples, which allows a rapid determination of Pt by adsorptive cathodic stripping voltammetry. A high pressure microwave system was used and the digestion was performed in HNO(3) and HCl. After digestion the HNO(3) was evaporated with a microwave assisted vacuum concentration set. The study resulted in a procedural detection limit of 37.5 ng L(-1) and a relative standard deviation of 18%. A recovery study resulted in a Pt loss below 5%. The microwave assisted evaporation of HNO(3) performed satisfactorily and up to 500 mL of the sample solution could be used for the voltammetric measurements without any effect on the peak heights. A direct comparison of Pt concentrations conducted after microwave digestion and digestion by high pressure ashing showed similar values. However, these promising results were not persistent throughout the repeated analysis using the same Teflon vessels. The vessels did not endure the harsh conditions and due to aging processes the Pt loss consistently increased until Pt determination in environmental relevant concentrations became impossible. Quartz vessels could not be employed as an alternative to the Teflon vessels, due to a lack of compatibility with the vacuum concentration system. Consequently, the results of this paper show that there is a need for further development of more resistant Teflon materials.

  16. Impacts of microwave pretreatments on the semi-continuous anaerobic digestion of dairy waste activated sludge

    Energy Technology Data Exchange (ETDEWEB)

    Uma Rani, R.; Adish Kumar, S. [Department of Civil Engineering, Regional Centre of Anna University, Tirunelveli 627 007, Tamil Nadu (India); Kaliappan, S. [Department of Civil Engineering, Ponjesly College of Engineering, Nagercoil 629 003, Tamil Nadu (India); Yeom, IckTae [Department of Civil and Environmental Engineering, Sungkyunkwan University (Korea, Republic of); Rajesh Banu, J., E-mail: rajeshces@gmail.com [Department of Civil Engineering, Regional Centre of Anna University, Tirunelveli 627 007, Tamil Nadu (India)

    2013-05-15

    Highlights: ► Microwave pretreatment of dairy WAS was studied. ► MW pretreatment at 70% intensity for 12 min, COD solubilization was 18.6%. ► Biogas production and SS reduction was 35% and 14% higher than control. ► In digester at 15 days SRT with medium OLR, SS and VS reduction was 67% and 64%. ► Biogas and methane production was 57% and 49% higher than control, in digesters. - Abstract: Microwave (MW) irradiation is one of the new and possible methods used for pretreating the sludge. Following its use in different fields, this MW irradiation method has proved to be more appropriate in the field of environmental research. In this paper, we focused on the effects of MW irradiation at different intensities on solubilization, biodegradation and anaerobic digestion of sludge from the dairy sludge. The changes in the soluble fractions of the organic matter, the biogas yield, the methane content in the biogas were used as control parameters for evaluating the efficiency of the MW pretreatment. Additionally, the energetic efficiency was also examined. In terms of an energetic aspect, the most economical pretreatment of sludge was at 70% intensity for 12 min irradiation time. At this, COD solubilization, SS reduction and biogas production were found to be 18.6%, 14% and 35% higher than the control, respectively. Not only the increase in biogas production was investigated, excluding protein and carbohydrate hydrolysis was also performed successfully by this microwave pretreatment even at low irradiation energy input. Also, experiments were carried out in semi continuous anaerobic digesters, with 3.5 L working volume. Combining microwave pretreatment with anaerobic digestion led to 67%, 64% and 57% of SS reduction, VS reduction and biogas production higher than the control, respectively.

  17. Determination of Pt from coke samples by ICP-MS after microwave assisted digestion and microwave assisted cloud point extraction

    Energy Technology Data Exchange (ETDEWEB)

    Niemela, M.; Huttunen, S.M.; Gornostayev, S.S.; Peramaki, P. [University of Oulu, Oulu (Finland). Dept. of Chemistry

    2009-09-15

    Platinum in coke samples was determined by inductively coupled plasma mass spectrometry (ICP-MS) after microwave-assisted sample digestion and temperature controlled microwave assisted cloud point extraction (MW-CPE). Interferences due to hafnium were successfully eliminated using MW-CPE with 2-MBT prior to the determination of platinum by ICP-MS. The validity of the method was studied by spike recovery tests and by analyzing certified reference material (BCR-723 street dust). The results obtained for platinum in the BCR-723 were generally in good agreement with the certified values. Furthermore, the preliminary platinum results obtained for coke sample by ICP-MS after MW-CPE were compared to those obtained by a reference method (NiS-Fire Assay preconcentration/Te coprecipitation and ICP-MS determination).

  18. 78 FR 4015 - Energy Conservation Program: Test Procedures for Microwave Ovens

    Science.gov (United States)

    2013-01-18

    ... RIN 1904-AB78 Energy Conservation Program: Test Procedures for Microwave Ovens AGENCY: Office of...) to amend the test procedures for microwave ovens. That SNOPR proposed amendments to the DOE test... measuring the standby mode and off mode energy use of products that combine a microwave oven with other...

  19. Enhancement of anaerobic digestion efficiency of wastewater sludge and olive waste: Synergistic effect of co-digestion and ultrasonic/microwave sludge pre-treatment.

    Science.gov (United States)

    Alagöz, B Aylin; Yenigün, Orhan; Erdinçler, Ayşen

    2015-12-01

    This study investigates the effect of ultrasonic and microwave pre-treatment on biogas production from the anaerobic co-digestion of olive pomace and wastewater sludges. It was found that co-digestion of wastewater sludge with olive pomace yielded around 0.21 L CH4/g VS added, whereas the maximum methane yields from the mono-digestion of olive pomace and un-pretreated wastewater sludges were 0.18 and 0.16L CH4/g VS added. In the same way, compared to mono-digestion of these substrates, co-digestion increased methane production by 17-31%. The microwave and ultrasonic pre-treatments applied to sludge samples prior to co-digestion process led to further increase in the methane production by 52% and 24%, respectively, compared to co-digestion with un-pretreated wastewater sludge. The highest biogas and methane yields were obtained from the co-digestion of 30 min microwave pre-treated wastewater sludges and olive pomace to be 0.46 L/g VS added and 0.32 L CH4/g VS added, respectively.

  20. EVALUATION OF HEAVY METALS CONTENT IN EDIBLE MUSHROOMS BY MICROWAVE DIGESTION AND FLAME ATOMIC ABSORPTION SPECTROMETRY

    OpenAIRE

    Cristiana Radulescu; Claudia Stihi; Valerica Gh. Cimpoca; Popescu, Ion V.; Gabriela Busuioc; Ana Irina Gheboianu

    2011-01-01

    The aim of this work was to determine the heavy metal (Cd, Cr, Ni, Pb, Mn, Zn, Fe and Cu) content of the fruiting bodies (cap and stipe) of four species (Amanita caesarea, Pleurotus ostreatus, Fistulina hepatica and Armillariella mellea) and their substrate, collected from forest sites in Dâmboviţa County, Romania. The elements were determined by Flame Atomic Absorption Spectrometry (FAAS) after microwave assisted digestion. From the same collecting point were taken n = 5 samples of young and...

  1. Analysis of Protein Amino Acids in Tobacco Using Microwave Digestion of Plant Material

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    Moldoveanu SC

    2014-12-01

    Full Text Available This paper describes a technique using microwave digestion and gas chromatography-mass spectrometry (GC-MS, which makes possible the analysis of protein amino acids in tobacco. The technique involves first the measurement of free amino acids, a hydrolysis using microwave digestion, and a measurement of total resulting amino acids. The content of protein amino acids is determined from the difference of total and free amino acids. The digestion is performed with aqueous 6 N HCl (with 1% phenol for two hours in a microwave at 120°C in sealed vials. The GC-MS analysis is performed after the amino acids are derivatized with N-methyl-N-(t-butyldimethylsilyltrifluoroacetamide (MTBSTFA. The technique provides reliable results with less than 10% relative standard deviation (RSD for most amino acids. Only the determination of very low level amino acids is affected by larger errors. The method provides results for free amino acids that are in very good agreement with those obtained by high performance liquid chromatography (HPLC, and also results for protein levels in tobacco in agreement with data previously reported in the literature. Results are given for several single grade tobaccos and for tobacco blends from four Kentucky reference cigarettes.

  2. Effect of microwave hydrolysis on transformation of steroidal hormones during anaerobic digestion of municipal sludge cake.

    Science.gov (United States)

    Hamid, Hanna; Eskicioglu, Cigdem

    2013-09-15

    Fate and removal of 16 steroidal (estrogenic, androgenic and progestogenic) hormones were studied during advanced anaerobic digestion of sludge cake using microwave (MW) pretreatment. Effect of pretreatment temperature (80, 120, 160 °C), operating temperature (mesophilic at 35 ± 2 °C, thermophilic at 55 ± 2 °C) and sludge retention time (SRT: 20, 10, 5 days) were studied employing eight lab-scale semi-continuously fed digesters. To determine the potential effect of MW hydrolysis, hormones were quantified in total (sorbed + soluble) and supernatant (soluble) phases of the digester influent and effluent streams. Seven of 16 hormones were above the method reporting limit (RL) in one or more of the samples. Hormone concentrations in total phase of un-pretreated (control) and pretreated digester feeds ranged in hormones from soluble and/or total phase. MW hydrolysis of the influent resulted in both release (from sludge matrix) and attenuation of hormones in the soluble phase. Accumulation of estrone (E1) as well as progesterone (Pr) and androstenedione (Ad) in most of the digesters indicated possible microbial transformations among the hormones. Compared to controls, all pretreated digesters had lower total hormone concentrations in their influent streams. At 20 days SRT, highest total removal (E1+E2+Ad +Pr) was observed for the thermophilic control digester (56%), followed by pretreated mesophilic digesters at 120 °C and 160 °C with around 48% efficiency. In terms of conventional performance parameters, relative (to control) improvements of MW pretreated digesters at a 5-d SRT ranged in 98-163% and 57-121%, for volatile solids removal and methane production, respectively.

  3. Characterization of undigested particulate material following microwave digestion of recycled document papers.

    Science.gov (United States)

    McGaw, Elizabeth A; Szymanski, David W; Smith, Ruth Waddell

    2009-09-01

    Recycled document paper was microwave digested in a solution of HNO(3) and H(2)O(2) prior to analysis by inductively coupled plasma mass spectrometry (ICP-MS) to determine the trace elemental concentrations within the paper. Undigested particulate material was observed and subsequently characterized as a mixture of kaolin (clay) and TiO(2) by Fourier transform infrared spectroscopy and X-ray diffraction spectroscopy. The effect of the particulate material on the elemental concentrations was then investigated. Paper samples were completely digested in hydrofluoric acid (HF) and element concentrations determined in the HF and HNO(3)/H(2)O digests were statistically compared using Student's t-test (95% confidence limit). Statistical differences in element concentrations between the two digests were observed for only four elements and there was no evidence of element adsorption by the particulate material. Hence, the HNO(3)/H(2)O(2) digestion proved sufficient to digest paper for ICP-MS analysis, eliminating the need to use the hazardous and corrosive HF matrix.

  4. Conductive heating and microwave hydrolysis under identical heating profiles for advanced anaerobic digestion of municipal sludge.

    Science.gov (United States)

    Mehdizadeh, Seyedeh Neda; Eskicioglu, Cigdem; Bobowski, Jake; Johnson, Thomas

    2013-09-15

    Microwave (2.45 GHz, 1200 W) and conventional heating (custom pressure vessel) pretreatments were applied to dewatered municipal waste sludge (18% total solids) using identical heating profiles that span a wide range of temperatures (80-160 °C). Fourteen lab-scale semi-continuous digesters were set up to optimize the energy (methane) output and sludge retention time (SRT) requirements of untreated (control) and thermally pretreated anaerobic digesters operated under mesophilic and thermophilic temperatures. Both pretreatment methods indicated that in the pretreatment range of 80-160 °C, temperature was a statistically significant factor (p-value heating, had no statistically significant effect (p-value >0.05) on sludge solubilization. With the exception of the control digesters at a 5-d SRT, all control and pretreated digesters achieved steady state at all three SRTs, corresponding to volumetric organic loading rates of 1.74-6.96 g chemical oxygen demand/L/d. At an SRT of 5 d, both mesophilic and thermophilic controls stopped producing biogas after 20 d of operation with total volatile fatty acids concentrations exceeding 1818 mg/L at pH <5.64 for mesophilic and 2853 mg/L at pH <7.02 for thermophilic controls, while the pretreated digesters continued producing biogas. Furthermore, relative (to control) organic removal efficiencies dramatically increased as SRT was shortened from 20 to 10 and then 5 d, indicating that the control digesters were challenged as the organic loading rate was increased. Energy analysis showed that, at an elevated temperature of 160 °C, the amount of methane recovered was not enough to compensate for the energy input. Among the digesters with positive net energy productions, control and pretreated digesters at 80 °C were more favorable at an SRT of 10 d.

  5. Microwave Assisted Alkali Pretreatment of Rice Straw for Enhancing Enzymatic Digestibility

    Directory of Open Access Journals (Sweden)

    Renu Singh

    2014-01-01

    Full Text Available Rapid industrialization, increasing energy demand, and climate change are the conditions that forced the researchers to develop a clean, efficient, renewable, and sustainable source of energy which has a potential to replace fossil fuels. Ethanol is one of the attractive and suitable renewable energy resources. In present study, effectiveness of microwave pretreatment in combination with sodium hydroxide (NaOH for increasing enzymatic hydrolysis of rice straw has been investigated and under optimum conditions obtained a maximum reducing sugar (1334.79 µg/mL through microwave assisted NaOH pretreatment. Chemical composition analysis and scanning electron microscope (SEM images showed that the removal of lignin, hemicellulose, and silicon content is more in microwave assisted NaOH pretreatment than the blank sample. X-ray diffraction (XRD analysis revealed that the crystallinity index of rice straw treated with microwave assisted alkali (54.55% is significantly high as compared to the blank (49.07%. Hence, the present study proves that microwave assisted alkali pretreatment can effectively enhance enzymatic digestibility of rice straw and it is feasible to convert rice straw for bioethanol production.

  6. Study on the Volatility of Cesium in Dry Ashing Pretreatment and Dissolution of Ash by Microwave Digestion System - 13331

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kwang-Soon; Lee, Chang Heon; Ahn, Hong-Joo; Park, Yong Joon; Song, Kyuseok [Nuclear Chemistry Research Division, Korea Atomic Energy Research Institute, Daedeok-daero 989-111, Yuseong-gu, Daejeon, 305-353 (Korea, Republic of)

    2013-07-01

    Based on the regulation of the activity concentration of Cs-137, Co-58, Co-60, Fe-55, Ni-59, Ni-63, Sr-90, Nb-94, and Tc-99, and the total alpha from the radioactive waste acceptance criteria, the measurement of the activity concentration of these nuclides in low and intermediate levels of radioactive waste such as in paper, cotton, vinyl and plastic samples was investigated. A dry ashing method was applied to obtain a concentration effect of the samples. Owing to the temperature dependence of the volatility for cesium, the temperature of 300 to 650 deg. C was examined. It was found that 450 deg. C is the optimum dry ashing temperature. After dry ashing, the produced ash was dissolved with HNO{sub 3}, HCl, and HF by a high-performance microwave digestion system. The ash sample, for the most part, was completely dissolved with 10 mL of HNO{sub 3}, 4 mL of HCl, and 0.25 mL of HF by a high-performance microwave digestion system using a nova high temperature rotor at 250 deg. C for 90 min until reaching 0.2 g. To confirm the reliability of cesium loss after the performance of the dry ashing procedure, a cesium standard solution for AAS and a Cs-137 standard solution for gamma spectrometry were added to a paper towel or a planchet of stainless steel, respectively. Cesium was measured by AAS, ICP-MS, and gamma spectrometry. The volatility of cesium did not occur until 450 deg. C ashing. (authors)

  7. [Analysis and comparison of trace elements of herba euphorbiae humifusae in different periods by microwave digestion-atomic absorption spectroscopy].

    Science.gov (United States)

    Xiong, Wei; Cai, Miao-zhen; Wang, Hong; Yu, Rui-peng; Cheng, Cun-gui

    2010-07-01

    Herba euphorbiae humifusae is the dried whole plant of Euphorbia humi fusa Willd. that belongs to euphorbiaceae. In the present paper, the microwave digestion procedure was used to digest herba euphorbiae humifusae collected in different periods, and then flame atomic absorption spectrometry (FAAS) was used to determine the contents of eight kinds of trace elements of herba euphorbiae humifusae in different periods, and the change in the contents of trace elements at different times was studied and analysed. The results showed that of all the trace elements of herba euphorbiae humifusae in different periods, element Fe was the highest in June, element K was in August at the highest level, element Mn reached the highest content in September, elements Na and Ca were dividedly at the highest content in October and November, and in December the highest content elements were Zn, Cu and Mg. In one word, the change of Na and Ca was jumping, while the change of Cu and Zn was comparatively mild. The results provide scientific basis for the time of collection of herba euphorbiae humifusae.

  8. 76 FR 65631 - Energy Conservation Program: Test Procedures for Microwave Ovens

    Science.gov (United States)

    2011-10-24

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY 10 CFR Part 430 RIN 1904-AC26 Energy Conservation Program: Test Procedures for Microwave Ovens AGENCY: Office... efficiency test procedure for microwave ovens under the Energy Policy and Conservation Act (EPCA). 75...

  9. 76 FR 72332 - Energy Conservation Program: Test Procedure for Microwave Ovens

    Science.gov (United States)

    2011-11-23

    ...-BT-TP-0011] RIN 1904-AB78 Energy Conservation Program: Test Procedure for Microwave Ovens AGENCY... 9, 2011, amending its test procedures for microwave ovens under the Energy Policy and Conservation... Secretary I. Background and Legal Authority Title III of the Energy Policy and Conservation Act (42...

  10. Digestion of plastic materials for the determination of toxic metals with a microwave oven for household use.

    Science.gov (United States)

    Sakurai, Hiroki; Noro, Junji; Kawase, Akira; Fujinami, Masanori; Oguma, Koichi

    2006-02-01

    A rapid sample-digestion method for the determination of toxic metals, cadmium, chromium, and lead, in polyethylene and polyvinyl chloride has been developed by using a microwave oven for household use. An appropriate amount of the sample taken in a PTFE decomposition vessel was mixed with nitric acid or nitric and sulfuric acids. The vessel was heated in a microwave oven by a predetermined operating program. The digested sample was diluted to a definite volume with water after evaporating most of the nitric acid. The precipitate, if formed, was filtered off by a membrane filter. The metals were determined by ICP-AES. The sample digestion required 5 min (for 20-mg sample) to 25 min (for 60-mg sample). The analytical results obtained for cadmium, chromium, and lead in a polyethylene certified reference material, BCR-680, digested with nitric acid, were in good agreement with the certified values.

  11. Ultrasound assisted biogas production from co-digestion of wastewater sludges and agricultural wastes: Comparison with microwave pre-treatment.

    Science.gov (United States)

    Aylin Alagöz, B; Yenigün, Orhan; Erdinçler, Ayşen

    2017-05-11

    This study investigates the effect of ultrasonication and microwave sludge disintegration/pre-treatment techniques on the anaerobic co-digestion efficiency of wastewater sludges with olive and grape pomaces. The effects of both co-digestion and sludge pre-treatment techniques were evaluated in terms of the organic removal efficiency and the biogas production. The "co-digestion" of wastewater sludge with both types of pomaces was revealed to be a much more efficient way for the biogas production compared to the single (mono) sludge digestion. The ultrasonication and microwave pre-treatments applied to the sludge samples caused to a further increase in biogas and methane yields. Based on applied specific energies, ultrasonication pre-treatment was found much more effective than microwave irradiation. The specific energy applied in microwave pre-treatment (87,000kj/kgTS) was almost 9 times higher than that of used in ultrasonication (10,000kj/kgTS), resulting only 10-15% increases in biogas/methane yield. Co-digestion of winery and olive industry residues with pre-treated wastewater sludges appears to be a suitable technique for waste management and energy production. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Microwave-assisted extraction and ultrasonic slurry sampling procedures for cobalt determination in geological samples by electrothermal atomic absorption spectroscopy.

    Science.gov (United States)

    Felipe-Sotelo, M; Carlosena, A; Fernández, E; López-Mahía, P; Muniategui, S; Prada, D

    2004-06-17

    Slurry sampling is compared to microwave-assisted acid digestion for cobalt determination in soil/sediment samples by electrothermal atomic absorption spectrometry (ETAAS). Furnace temperature programs and appropriate amounts of three chemical modifiers were optimised in order to get the highest signals and good separations between the atomic and background signals. Using nitric acid (0.5% (v/v)) as liquid medium, no chemical modifier was needed. The detection limit, based on integrated absorbance, was 0.04mugg(-1) for digests and slurries. Within-batch precision and analytical recoveries were satisfactory for both procedures. Accuracy was tested by analysing a reference soil and a sediment from IRMM. The methods were further compared employing a set of roadside soils and estuarine sediments. As no significant differences (95% confidence) were found, practical analytical properties were suggested in order to select one of them.

  13. Enhancement of thermophilic anaerobic digestion of thickened waste activated sludge by combined microwave and alkaline pretreatment

    Institute of Scientific and Technical Information of China (English)

    Yongzhi Chi; Yuyou Li; Xuening Fei; Shaopo Wang; Hongying Yun

    2011-01-01

    Pretreatment of thickened waste activated sludge (TWAS) by combined microwave and alkaline pretreatment (MAP) was studied to improve thermophilic anaerobic digestion efficiency.Uniform design was applied to determine the combination of target temperature (110-210℃),microwave holding time (1-51 min),and NaOH dose (0-2.5 g NaOH/g suspended solids (SS)) in terms of their effect on volatile suspended solids (VSS) solubilization.Maximum solubilization ratio (85.1%) of VSS was observed at 210℃ with 0.2 g-NaOH/g-SS and 35 min holding time.The effects of 12 different pretreatment methods were investigated in 28 thermophilic batch reactors by monitoring cumulative methane production (CMP).Improvements in methane production in the TWAS were directly related to the microwave and alkaline pretreatment of the sludge.The highest CMP was a 27% improvement over the control.In spite of the increase in soluble chemical oxygen demand concentration and the decrease in dewaterability of digested sludge,a semi-continuous thennophilic reactor fed with pretreated TWAS without neutralization (at 170℃ with 1 rain holding time and 0.05 g NaOH/g SS) was stable and functioned well,with volatile solid (VS) and total chemical oxygen demand (TCOD) reductions of 28% and 18%,respectively,which were higher than those of the control system.Additionally,methane yields (L@STP/g-CODadded,at standard temperature and pressure (STP) conditions of 0℃ and 101.325 kPa) and (L@STP/g VSadded) increased by 17% and 13%,respectively,compared to the control reactor.

  14. Optimization of microwave vacuum drying parameters for germinated lentils based on starch digestibility, antioxidant activity and total phenolic content

    Directory of Open Access Journals (Sweden)

    Robbarts Nongmaithem

    2017-04-01

    Full Text Available The aim of this study was to optimize the processing parameters of pulse mode microwave-vacuum drying of germinated green and red lentils (CDC Greenland and CDC Maxim and investigate the changes in their total phenolic content (TPC, total antioxidant activity (TAA and in-vitro starch digestibility (SD. The lentils were germinated for 5 days and dried by a pulse mode microwave-vacuum method, using 2 s to 8 s out of 10 s pulsed mode at 2000W microwave power and varying the vacuum pressure level between 15 and 45 kPa. In-vitro starch digestibility increased significantly with increased microwave power level. The TPC and TAA appeared to vary distinctively in the two varieties of selected lentils. Vacuum pressure levels did not significantly (p>0.05 affect any responses. Green lentils could be dried at 8 s microwave power and 45 kPa vacuum pressure and red lentils could be dried at 5.5 s microwave power and 42.19 kPa vacuum pressure. The microwave-vacuum drying showed great potential for the drying of germinated lentils.

  15. [Study of the elements determination method in animal fur by microwave digestion ICP-AES].

    Science.gov (United States)

    Hou, Tian-ping; Wang, Song-jun; Cao, Lin; Chang, Ping; Hou, Yue

    2008-08-01

    Considering the complex matrix of the sample, the animal fur is carried on to the sample pretreatment method studies specially. The microwave closed system has its unique merit: The microwave radiation has the very strong penetrability and the rapid in-depth heating function. After absorbing microwave the sample and the molecules of reactant may carry on the reaction in short time. But the microwave power is very weak, reaction consumes much time, the resolution is also incomplete. Besides the output excessively is high dispels in the pot the reagent differential pressure to increase the test solution to produce the storm rapidly to boil. As a result of those flaws, the minute step microwave heating digestion method is used to digest test specimen after treated by the acid pickling over night. In the experiment, the specialized microwave reactor is replaced by civil microwave; the microwave heating technology is adopted. According to the different characteristics of reagents, different allocated proportion and the test solution volume of nitric acid, hydrogen peroxide, hydrochloric acid and the water are tested separately. Meanwhile, in order to optimize the experimental condition, the different response power and respond time is also studied. At last, the experimental condition is determined: HNO3-H2O2-HCl-H2O acid system is chose(four reagent allocated proportions are 8:1:1:5); test specimen is heated up 10 minutes when the output is 150 W and 5 minutes when the output is 360 W continuously; carries on the test specimen airtight resolution processing animal fur by the sample. To guarantee the standard solution system is consistent with the biological sample substrate, the artificial simulation biology sample substrate is used to match law configuration standard solution; the ration the substrate element calcium is added. To eliminate disturbance of the sample complex substrate, the substrate match law, which reduces the substrate element disturbance is used

  16. Microwave-ultrasound combined reactor suitable for atmospheric sample preparation procedure of biological and chemical products

    NARCIS (Netherlands)

    Lagha, A.; Chemat, S.; Bartels, P.V.; Chemat, F.

    1999-01-01

    A compact apparatus in which a specific position can be irradiated by microwaves (MW) and ultrasound (US) simultaneously has been developed. The MW-US reactor has been designed for atmospheric pressure digestion and dissolution of biological and chemical products. The reactor can treat a range of th

  17. Microwave assisted digestion followed by ICP-MS for determination of trace metals in atmospheric and lake ecosystem.

    Science.gov (United States)

    Ahmed, Manan; Chin, Ying Hui; Guo, Xinxin; Zhao, Xing-Min

    2017-05-01

    The study of trace metals in the atmosphere and lake water is important due to their critical effects on humans, aquatic animals and the geochemical balance of ecosystems. The objective of this study was to investigate the concentration of trace metals in atmospheric and lake water samples during the rainy season (before and after precipitation) between November and December 2015. Typical methods of sample preparation for trace metal determination such as cloud point extraction, solid phase extraction and dispersive liquid-liquid micro-extraction are time-consuming and difficult to perform; therefore, there is a crucial need for development of more effective sample preparation procedure. A convection microwave assisted digestion procedure for extraction of trace metals was developed for use prior to inductively couple plasma-mass spectrometric determination. The result showed that metals like zinc (133.50-419.30μg/m(3)) and aluminum (53.58-378.93μg/m(3)) had higher concentrations in atmospheric samples as compared to lake samples before precipitation. On the other hand, the concentrations of zinc, aluminum, chromium and arsenic were significantly higher in lake samples after precipitation and lower in atmospheric samples. The relationship between physicochemical parameters (pH and turbidity) and heavy metal concentrations was investigated as well. Furthermore, enrichment factor analysis indicated that anthropogenic sources such as soil dust, biomass burning and fuel combustion influenced the metal concentrations in the atmosphere. Copyright © 2016. Published by Elsevier B.V.

  18. Evaluation of Acid Digestion Procedures to Estimate Mineral Contents in Materials from Animal Trials.

    Science.gov (United States)

    Palma, M N N; Rocha, G C; Valadares Filho, S C; Detmann, E

    2015-11-01

    Rigorously standardized laboratory protocols are essential for meaningful comparison of data from multiple sites. Considering that interactions of minerals with organic matrices may vary depending on the material nature, there could be peculiar demands for each material with respect to digestion procedure. Acid digestion procedures were evaluated using different nitric to perchloric acid ratios and one- or two-step digestion to estimate the concentration of calcium, phosphorus, magnesium, and zinc in samples of carcass, bone, excreta, concentrate, forage, and feces. Six procedures were evaluated: ratio of nitric to perchloric acid at 2:1, 3:1, and 4:1 v/v in a one- or two-step digestion. There were no direct or interaction effects (p>0.01) of nitric to perchloric acid ratio or number of digestion steps on magnesium and zinc contents. Calcium and phosphorus contents presented a significant (p0.01) calcium or phosphorus contents in carcass, excreta, concentrate, forage, and feces. Number of digestion steps did not affect mineral content (p>0.01). Estimated concentration of calcium, phosphorus, magnesium, and zinc in carcass, excreta, concentrated, forage, and feces samples can be performed using digestion solution of nitric to perchloric acid 4:1 v/v in a one-step digestion. However, samples of bones demand a stronger digestion solution to analyze the mineral contents, which is represented by an increased proportion of perchloric acid, being recommended a digestion solution of nitric to perchloric acid 2:1 v/v in a one-step digestion.

  19. An evaluation of microwave-assisted fusion and microwave-assisted acid digestion methods for determining elemental impurities in carbon nanostructures using inductively coupled plasma optical emission spectrometry

    KAUST Repository

    Patole, Shashikant P.

    2015-10-21

    It is common for as-prepared carbon nanotube (CNT) and graphene samples to contain remnants of the transition metals used to catalyze their growth; contamination may also leave other trace elemental impurities in the samples. Although a full quantification of impurities in as-prepared samples of carbon nanostructures is difficult, particularly when trace elements are intercalated or encapsulated within a protective layer of graphitic carbon, reliable information is essential for reasons such as quantifying the adulteration of physico-chemical properties of the materials and for evaluating environmental issues. Here, we introduce a microwave-based fusion method to degrade single- and double-walled CNTs and graphene nanoplatelets into a fusion flux thereby thoroughly leaching all metallic impurities. Subsequent dissolution of the fusion product in diluted hydrochloric and nitric acid allowed us to identify their trace elemental impurities using inductively coupled plasma optical emission spectrometry. Comparisons of the results from the proposed microwave-assisted fusion method against those of a more classical microwave-assisted acid digestion approach suggest complementarity between the two that ultimately could lead to a more reliable and less costly determination of trace elemental impurities in carbon nanostructured materials. Graphical abstract A method for the complete digestion of carbon nanostructures has been demonstrated. Photographs (on the left side) show zirconium crucibles containing SWCNTs with flux of Na2CO3 and K2CO3, before and after microwave fusion; (on the right side) the appearance of the final solutions containing dissolved samples, from microwave-assisted fusion and microwave-assisted acid digestion. These solutions were used for determining the trace elemental impurities by ICP‒OES.

  20. Determination of sodium in foods by flame atomic absorption spectrometry after microwave digestion: NMKL interlaboratory study.

    Science.gov (United States)

    Julshamn, Kaare; Lea, Per; Norli, Hilde Skaar

    2005-01-01

    Nine laboratories participated in an interlaboratory method performance (collaborative) study of a method for the determination of sodium in foods by flame atomic absorption spectrometry after wet digestion, using a microwave oven technique. Before the study, the laboratories were able to practice on samples with defined sodium levels (pretrial test). The method was tested on a total of 6 foods (broccoli, carrot, bread, saithe fillet, pork, and cheese) with sodium concentrations of 1480-8260 mg/kg. The materials were presented to the participants in the study as blind duplicates, and the participants were asked to perform single determinations for each sample. The repeatability relative standard deviations (RSDr) for sodium ranged from 1.9 to 6.5%. The reproducibility relative standard deviations (RSDR) ranged from 4.2 to 6.9%. The HorRat values ranged from 0.9 to 1.6.

  1. 40 CFR 136.3 - Identification of test procedures.

    Science.gov (United States)

    2010-07-01

    ....14 3 DCP See footnote 34 37. Nickel—Total,4 mg/L Digestion 4 followed by: AA direct aspiration 36... EPA Method 200.2 or an approved alternate procedure (e.g., CEM microwave digestion, which may be used..., “Precision and Recovery Statements for Methods for Measuring Metals.” 36 Microwave-assisted digestion may...

  2. The effects of post-persulfate-digestion procedures on total phosphorus analysis in water.

    Science.gov (United States)

    Zhou, Meifang; Struve, David M

    2004-11-01

    There are differences between the EPA Method 365 and the APHA-AWWA-WEF's Standard Method 4500 with respect to the post-digestion treatment procedures of the persulfate-digested water. The effects on total phosphorus analysis of different post-digestion treatment procedures, such as neutralization and reacidification, and shaking/settling, were investigated in this study using the total phosphorus measurements of water samples from the Everglades Round Robin (ERR) study and comparing the results with the ERR study. The effects of the insoluble particles or phosphorus adsorption/precipitation on/with Al and Fe hydroxides in different post-digestion treatment procedures adequately accounted for the differences between the most probable value and the higher or lower total phosphorus measurements reported in the ERR study. Based on the results of this investigation we recommend that a clearly defined set of digestion and post-digestion treatment procedures be adopted as the standard for total phosphorus analysis using the ascorbic acid method.

  3. Dissolution of fluoride complexes following microwave-assisted hydrofluoric acid digestion of marine sediments.

    Science.gov (United States)

    Muratli, Jesse M; McManus, James; Mix, Alan; Chase, Zanna

    2012-01-30

    Microwave-assisted, hydrofluoric acid digestion is an increasingly common tool for the preparation of marine sediment samples for analysis by a variety of spectrometric techniques. Here we report that analysis of terrigenous-dominated sediment samples occasionally results in anomalously low values for several elements, including Al, Ba, Ca, Mg, and Sr. Measured concentrations of these elements increased with time between sample preparation and sample analysis, reaching stable values after 8-29 days. This lag is explained by the formation and subsequent dissolution of poorly soluble fluoride phases during digestion. Other elements, such as Fe, Mn, and Ti, showed little or no lag and were quickly measurable at a stable value. Full re-dissolution of the least soluble fluorides, which incorporate Al and Mg, requires up to four weeks at room temperature, and this duration can vary among sedimentary matrices. This waiting time can be reduced to 6 days (or shorter) if the samples are heated to ≈ 60°C for 24h.

  4. Evaluation of single vs. staged mesophilic anaerobic digestion of kitchen waste with and without microwave pretreatment.

    Science.gov (United States)

    Shahriari, Haleh; Warith, Mostafa; Hamoda, Mohamed; Kennedy, Kevin

    2013-08-15

    Effects of single and dual stage (acidogenic-methanogenic) mesophilic anaerobic digestion (AD) of kitchen waste (KW) was evaluated at hydraulic retention times (HRTs) of 20, 15, 12 and 9 d with and without thermal microwave (MW) pretreatment (145 °C). Anaerobic acidification in terms of acid accumulation was superior compared to microaerophilic acidification. Maximum anaerobic acidification of KW was determined to occur with an HRT of 2 d which was then selected for the acidification stage. The dual stage AD system fed with untreated KW produced the maximum biogas and volatile solids (VS) stabilization efficiencies at the shortest HRT of 9 d. Conversely, for free liquid resulting from MW pretreatment of KW the two stage reactor at 20 d HRT produced three fold more methane compared with the untreated free liquid control. However, MW pretreatment and AD of the free liquid fraction only, was not a sustainable treatment option. For KW, staging of the AD process had a greater positive impact on waste stabilization and methane yield compared to single stage reactors or MW pretreatment. KW can be characterized as being a readily biodegradable solid waste; concomitantly it is recommended that digester staging without MW pretreatment be employed to maximize methane yield and production.

  5. [Determination of eight metal elements in Cichorium glandulosum Boiss et Huet by microwave digestion-FAAS].

    Science.gov (United States)

    Pei, Ling-Peng; Zhou, Xiao-Ying; Cui, Jian; Pang, Zong-Ran; Liu, Hong-Bing; Ge, Liang

    2009-12-01

    The Cichorium glandulosum Boiss et Huet is a traditional Uighur natural herbal medicine, but has not been analyzed and studied in terms of its metal elements. In the experiment, the Cichorium glandulosum Boiss et Huet powder was digested with HNO3 by microwave digestion before determination. The eight metal elements, potassium, nickel, calcium, magnesium, iron, manganese, copper and zinc, in Cichorium glandulosum Boiss et Huet were determined by FAAS. The working conditions, accuracy and precision of the method were studied. The linear correlations of standard curves are good (r = 0.999 1-0.999 9). The recovery (n = 6) is 92.25%-110.5%, and the RSD (n = 6) is 0.7%-3.88%. The results showed that there were comparatively rich metal elements, among which are comparatively high calcium (65.84 mg x g(-1)), iron (24.38 mg x g(-1)), magnesium (278.17 mg x g(-1)) and potassium (18.50 mg x g(-1)), in Cichorium glandulosum Boiss et Huet, and the contents of other elements are nickel of 0.004 38 mg x g(-1), manganese of 0.52 mg x g(-1), copper of 0.016 5 mg x g(-1) and zinc of 0.18 mg x g(-1). This provided useful data for discussing the relationship between the content of the metal elements in Cichorium glandulosum Boiss et Huet and its clinical application in cardiovascular and osteoporosis disease.

  6. Behavioral observations and operant procedures using microwaves as a heat source for young chicks

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, W.D.; McMillan, I.; Bate, L.A.; Otten, L.; Pei, D.C.

    1986-08-01

    Four trials, using operant conditioning procedures, were conducted to study the response of chicks, housed at 16 C, to microwave or infrared heat. Microwave power density was 26 mW/cm2 in Trial 1, 13 mW/cm2 in Trial 2, and 10 mW/cm2 in Trials 3 and 4. Chicks voluntarily demanded between 28 and 63% as much heat (min heat/hr) from microwave source as from infrared source at all power densities. There was no correlation, however, between the ratio of heat demanded and the power density used. There were no significant differences in growth between infrared- or microwave-heated chicks. It is evident from these studies that 8-day-old broiler chicks are capable of associating the performance of a task with a thermal reward provided by the microwaves. They are also able to utilize these microwaves through operant conditioning without any visible detrimental effect to their health or behavior.

  7. Rheological properties of sewage sludge during enhanced anaerobic digestion with microwave-H2O2 pretreatment.

    Science.gov (United States)

    Liu, Jibao; Yu, Dawei; Zhang, Jian; Yang, Min; Wang, Yawei; Wei, Yuansong; Tong, Juan

    2016-07-01

    The rheological behavior of sludge is of serious concern in anaerobic digestion. This study investigated the rheological properties of sewage sludge during enhanced anaerobic digestion with microwave-H2O2 pretreatment (MW-H2O2). The results showed that MW-H2O2 pretreatment resulted in the improvement of sludge flowability and weakening of its viscoelastic properties. Further positive effects on the rheological properties of digested sludge during anaerobic digestion were observed. The flowability was improved with a low level of apparent viscosity. The decrease of the consistency index and increase of the flow behavior index indicated that the strength of the inner structures and non-Newtonian flow characteristics of digested sludge weakened. Both the storage modulus (G') and loss modulus (G″) decreased, indicating that the viscoelastic behavior became weak. These effects were possibly attributed to the changes of the digested sludge micro-structures, such as extracellular polymeric substances (EPS). This study concluded that anaerobic digestion for treating sewage sludge combined with pretreatment is a more favorable option than single anaerobic digestion from the perspective of rheology.

  8. Atmospheric pressure microwave sample preparation procedure for the combined analysis of total phosphorus and kjeldahl nitrogen.

    Science.gov (United States)

    Collins, L W; Chalk, S J; Kingston, H M

    1996-08-01

    An atmospheric pressure microwave digestion method has been developed for the combined analysis of total phosphorus and Kjeldahl nitrogen in complex matrices. In comparison to the digestion steps in EPA Methods 365.4 (total phosphorus) and 351.x (Kjeldahl nitrogen), this method requires less time, eliminates the need for a catalyst, and reduces the toxicity of the waste significantly. It employs a microwave-assisted digestion step, using refluxing borosilicate glass vessels at atmospheric pressure. Traditionally, this method has a time-consuming sample preparation step and generates toxic waste through the use of heavy metal catalysts. These advantages are gained by the combination of a high boiling point acid (sulfuric acid) and the application of focused microwave irradiation, which enhances the digestion process by direct energy coupling. NIST standard reference materials 1572 (citrus leaves), 1577a (bovine liver), and 1566 (oyster tissue) and tryptophan were analyzed to validate the method. Phosphorus concentrations were determined by the colorimetric ascorbic acid method outlined in EPA Method 365.3. Kjeldahl nitrogen concentrations were determined using EPA Method 351.1. The results of the analyses showed good precision and are in excellent agreement with the NIST published values for both elements.

  9. A simple design for microwave assisted digestion vessel with low reagent consumption suitable for food and environmental samples

    Science.gov (United States)

    Gholami, Mehrdad; Behkami, Shima; Zain, Sharifuddin Md.; Bakirdere, Sezgin

    2016-11-01

    The objective of this work is to prepare a cost-effective, low reagent consumption and high performance polytetrafluoroethylene (PTFE) vessel that is capable to work in domestic microwave for digesting food and environmental samples. The designed vessel has a relatively thicker wall compared to that of commercial vessels. In this design, eight vessels are placed in an acrylonitrile butadiene styrene (ABS) holder to keep them safe and stable. This vessel needs only 2.0 mL of HNO3 and 1.0 mL H2O2 to digest 100 mg of biological sample. The performance of this design is then evaluated with an ICP-MS instrument in the analysis of the several NIST standard reference material of milk 1849a, rice flour 1568b, spinach leave 1570a and Peach Leaves 1547 in a domestic microwave oven with inverter technology. Outstanding agreement to (SRM) values are observed by using the suggested power to time microwave program, which simulates the reflux action occurring in this closed vessel. Taking into account the high cost of commercial microwave vessels and the volume of chemicals needed for various experiments (8–10 mL), this simple vessel is cost effective and suitable for digesting food and environmental samples.

  10. Determination of trace nickel in hydrogenated cottonseed oil by electrothermal atomic absorption spectrometry after microwave-assisted digestion.

    Science.gov (United States)

    Zhang, Gai

    2012-01-01

    Microwave digestion of hydrogenated cottonseed oil prior to trace nickel determination by electrothermal atomic absorption spectrometry (ETAAS) is proposed here for the first time. Currently, the methods outlined in U.S. Pharmacopeia 28 (USP28) or British Pharmacopeia (BP2003) are recommended as the official methods for analyzing nickel in hydrogenated cottonseed oil. With these methods the samples may be pre-treated by a silica or a platinum crucible. However, the samples were easily tarnished during sample pretreatment when using a silica crucible. In contrast, when using a platinum crucible, hydrogenated cottonseed oil acting as a reducing material may react with the platinum and destroy the crucible. The proposed microwave-assisted digestion avoided tarnishing of sample in the process of sample pretreatment and also reduced the cycle of analysis. The programs of microwave digestion and the parameters of ETAAS were optimized. The accuracy of the proposed method was investigated by analyzing real samples. The results were compared with the ones by pressurized-PTFE-bomb acid digestion and ones obtained by the U.S. Pharmacopeia 28 (USP28) method. The new method involves a relatively rapid matrix destruction technique compared with other present methods for the quantification of metals in oil.

  11. [Determination of trace elements in waste beer yeasts by ICP-MS with microwave digestion].

    Science.gov (United States)

    Cheng, Xian-zhong; Jin, Can; Zhang, Kai-cheng

    2008-10-01

    The waste beer yeast has rich nutritional compositions and is widely used in food, medical and forage industries. The security of the yeast plays an important role in everyone's daily life. But the yeast contanining microamount of lead, cadmium, chromium, arsenic and other harmful metals is endangering human health. A new method was developed for the direct determination of eight elements, namely copper, lead, zinc, iron, manganese, cadmium, chromium and arsenic in waste beer yeast by inductively coupled plasma-mass spectrometry (ICP-MS) with microwave digestion. The parameters of plasma system, mass system, vacuum system and spectrometer system were optimized. The spectral interferences were eliminated by selecting alternation analytical isotopes of 65Cu, 208Pb, 66Zn, 57Fe, 55Mn, 114Cd, 52Cr and 5As, and the internal standards of Rh was selected to compensate the drift of analytical signals. The samples were digested with concentrated nitric acid-hydrogen peroxide (2:1) mixed solution more rapidly and more effectively. The effects of the type of mixed acid , the volume of digesting solution, heating time, and heating power were investigated in detail. In the closed system, the complete digestion was performed using 4 mL HNO3 and 2mL H2O2 for 2.0 min at 0.5 MPa, 3 min at 1.0 MPa and 5 min at 1.5 MPa. The detection limits of these eight elements were 0.013-0.122 microg x L(-1). The relative standard deviation (RSD) was 0.94%-3.26% (n=9), and the addition standard recovery was 98.4%-102.6% for all elements. The proposed method has been applied to the determination of trace elements of Cu, Pb, Zn, Fe, Mn, Cd, Cr and As in waste beer yeast samples with satisfactory results. The determination results indicated that the content of trace elements of Cu, Pb, Cd and As in waste beer yeast samples are significantly low.

  12. Effect of Microwave and Ultrasonic Pretreatments on Biogas Production from Anaerobic Digestion of Palm Oil Mill Effleunt

    Directory of Open Access Journals (Sweden)

    N. Saifuddin

    2009-01-01

    Full Text Available Problem Statement: Oil palm production is a major agricultural industry in Malaysia. In 2006, palm oil mills in Malaysia produced more than 58 million tonnes of Palm Oil Mill Effluent (POME. Existing treatment in a series of open lagoons at high ambient temperatures, results in the uncontrolled production of methane and carbon dioxide, which are both green house gases (GHGs. With the increased worldwide concern on environmentally friendly production processes particularly the emission of methane, it is important to develop an alternative concept for POME treatment. This study elucidates the effects of pre-treatment of palm oil mill effluent by microwave irradiation and ultrasonic on anaerobic digestion. Approach: Effects of pre-treatment on sludge characterisation parameters were monitored. The Soluble Chemical Oxygen Demand (SCOD/total COD ratio and biodegradability of soluble organic matter increased significantly after both the pre-treatments which indicated an increase in disintegration of the floc structure of the sludge. Three identical bioreactors with working volume of 5 litres were used as anaerobic digesters at 32-35°C. The reactors were separately fed with pre-treated sludge (microwave, ultrasonic and combination of microwave and ultrasonic and control sludge at different Hydraulic Retention Times (HRT to check for the production of methane. Results: The maximum SCOD/TCOD ratio reached almost 29% after 30 min of ultrasonic treatment, while it was 45% after 7 min of microwave irradiation. The BOD5/SCOD ratio also increased after the pre-treatments suggesting the biodegradability of the soluble organic material increased during the treatment. It was observed that TVFA released was increased after both the treatments, with microwave treatment showing a higher yield of TVFA. Greatest enhancement in methane production was shown by the 3 min microwave plus 10 min ultrasonic treatment. Conclusion: The microwave in combination with

  13. Comparison of Dilution, Filtration, and Microwave Digestion Sample Pretreatments in Elemental Profiling of Wine by ICP-MS.

    Science.gov (United States)

    Godshaw, Joshua; Hopfer, Helene; Nelson, Jenny; Ebeler, Susan E

    2017-09-25

    Wine elemental composition varies by cultivar, geographic origin, viticultural and enological practices, and is often used for authenticity validation. Elemental analysis of wine by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is challenging due to the potential for non-spectral interferences and plasma instability arising from organic matrix components. Sample preparation mitigates these interferences, however, conflicting recommendations of best practices in ICP-MS analysis of wine have been reported. This study compared direct dilution, microwave-assisted acid digestion, and two filtration sample pretreatments, acidification prior to filtration and filtration followed by acidification, in elemental profiling of one white and three red table wines by ICP-MS. Of 43 monitored isotopes, 37 varied by sample preparation method, with significantly higher results of 17 isotopes in the microwave-digested samples. Both filtration treatments resulted in lower results for 11 isotopes compared to the other methods. Finally, isotope dilution determination of copper based on natural abundances and the (63)Cu:(65)Cu instrument response ratio agreed with external calibration and confirmed a significant sample preparation effect. Overall, microwave digestion did not compare favorably, and direct dilution was found to provide the best compromise between ease of use and result accuracy and precision, although all preparation strategies were able to differentiate the wines.

  14. Optimization of microwave pretreatment conditions to maximize methane production and methane yield in mesophilic anaerobic sludge digestion.

    Science.gov (United States)

    Park, W J; Ahn, J H

    2011-10-01

    The objective of this study was to find optimum microwave pretreatment conditions for methane production and methane yield in anaerobic sludge digestion. The sludge was pretreated using a laboratory-scale industrial microwave unit (2450 MHz frequency). Microwave temperature increase rate (TIR) (2.9-17.1 degrees C/min) and final temperature (FT) (52-108 degrees C) significantly affected solubilization, methane production, and methane yield. Solubilization degree (soluble chemical oxygen demand (COD)/total COD) in the pretreated sludge (3.3-14.7%) was clearly higher than that in the raw sludge (2.6%). Within the design boundaries, the optimum conditions for maximum methane production (2.02 L/L) were TIR = 9.1 degrees C/min and FT = 90 degrees C, and the optimum conditions for maximum methane yield (809 mL/g VS(removed)) were TIR 7.1 degrees C/min and FT = 92 degrees C.

  15. Determination of mercury in rice by cold vapor atomic fluorescence spectrometry after microwave-assisted digestion

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Maria Jose da [Department of Analytical Chemistry, Edificio de Investigacion, University of Valencia, 50 Dr. Moliner Street, E-46100 Burjassot, Valencia (Spain); Departamento de Quimica Fundamental, Universidade Federal de Pernambuco, Cidade Universitaria, 50740-550 Recife, PE (Brazil); Paim, Ana Paula S. [Departamento de Quimica Fundamental, Universidade Federal de Pernambuco, Cidade Universitaria, 50740-550 Recife, PE (Brazil); Pimentel, Maria Fernanda [Departamento de Engenharia Quimica, Universidade Federal de Pernambuco, Recife, PE (Brazil); Cervera, M. Luisa, E-mail: m.luisa.cervera@uv.es [Department of Analytical Chemistry, Edificio de Investigacion, University of Valencia, 50 Dr. Moliner Street, E-46100 Burjassot, Valencia (Spain); Guardia, Miguel de la [Department of Analytical Chemistry, Edificio de Investigacion, University of Valencia, 50 Dr. Moliner Street, E-46100 Burjassot, Valencia (Spain)

    2010-05-14

    A cold vapor atomic fluorescence spectrometry method (CV-AFS) has been developed for the determination of Hg in rice samples at a few ng g{sup -1} concentration level. The method is based on the previous digestion of samples in a microwave oven with HNO{sub 3} and H{sub 2}O{sub 2} followed by dilution with water containing KBr/KBrO{sub 3} and hydroxylamine and reduction with SnCl{sub 2} in HCl using external calibration. The matrix interferences and the effect of nitrogen oxide vapors have been evaluated and the method validated using a certified reference material. The limit of detection of the method was 0.9 ng g{sup -1} with a recovery percentage of 95 {+-} 4% at an added concentration of 5 ng g{sup -1}. The concentration level of Hg found in 24 natural rice samples from different origin ranged between 1.3 and 7.8 ng g{sup -1}.

  16. EVALUATION OF HEAVY METALS CONTENT IN EDIBLE MUSHROOMS BY MICROWAVE DIGESTION AND FLAME ATOMIC ABSORPTION SPECTROMETRY

    Directory of Open Access Journals (Sweden)

    Cristiana Radulescu

    2011-05-01

    Full Text Available The aim of this work was to determine the heavy metal (Cd, Cr, Ni, Pb, Mn, Zn, Fe and Cu content of the fruiting bodies (cap and stipe of four species (Amanita caesarea, Pleurotus ostreatus, Fistulina hepatica and Armillariella mellea and their substrate, collected from forest sites in Dâmboviţa County, Romania. The elements were determined by Flame Atomic Absorption Spectrometry (FAAS after microwave assisted digestion. From the same collecting point were taken n = 5 samples of young and mature fruiting bodies of mushrooms and their substrate. The high concentrations of lead, chrome and cadmium (Pb: 0.25 – 1.89 mg.kg-1, Cr: 0.36 – 1.94 mg.kg-1, Cd: 0.23 – 1.13 mg.kg-1 for all collected wild edible mushrooms, were determined. These data were compared with maximum level for certain contaminants in foodstuffs established by the commission of the European Committees (EC No 466/2001. A quantitative evaluation of the relationship of element uptake by mushrooms from substrate was made by calculating the accumulation coefficient (Ka. The moderately acid pH value of soil influenced the accumulation of Zn and Cd inside of the studied species. The variation of heavy metals content between edible mushrooms species is dependent upon the ability of the species to extract elements from the substrate and on the selective uptake and deposition of metals in tissue.

  17. Application of microwave digestion/AAS in detecting crankshaft bearing knock.

    Science.gov (United States)

    Chen, Li-dan; Zhao, Yan-ru

    2014-06-01

    The present study was carried out to detect crankshaft bearing knock using atomic absorption spectrometry (AAS) in an innovative way. Lubricating oil of MAGOTAN 2.0 with mileage of 1000-28000Km and sampling interval of 1000Km changed into atomic vapor in the heat after digesting with microwave. Hollow --cathode lamp made of the same element with metal content under test would radiate characteristic radiation with certain wavelength. A part of atomic vapor was launched with ground state atom after heating with graphite furnace. Concentration-absorbance working curve was finished with standard series sample after absorbance was measured. Finally, element content under test in oil was obtained based on the work curve. Database of primary element (Cu and Pb) content of lubricating oil in the same engine with different mileage was established. Results showed that Cu, Pb content fluctuates with different mileage in a certain range. In practical engineering applications, primary metal content in lubricating oil of engine crankshaft bearing was measured and compared with content variation trend chart. This new method not only helps automobile maintenance personnel to diagnose crankshaft bearing knock under no-disintegration situation but also is benefit for reducing the maintenance cost of automobile greatly and improving diagnostic accuracy of crankshaft bearing knock.

  18. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; comparison of a nitric acid in-bottle digestion procedure to other whole-water digestion procedures

    Science.gov (United States)

    Garbarino, John R.; Hoffman, Gerald L.

    1999-01-01

    A hydrochloric acid in-bottle digestion procedure is used to partially digest wholewater samples prior to determining recoverable elements by various analytical methods. The use of hydrochloric acid is problematic for some methods of analysis because of spectral interference. The inbottle digestion procedure has been modified to eliminate such interference by using nitric acid instead of hydrochloric acid in the digestion. Implications of this modification are evaluated by comparing results for a series of synthetic whole-water samples. Results are also compared with those obtained by using U.S. Environmental Protection Agency (1994) (USEPA) Method 200.2 total-recoverable digestion procedure. Percentage yields that use the nitric acid inbottle digestion procedure are within 10 percent of the hydrochloric acid in-bottle yields for 25 of the 26 elements determined in two of the three synthetic whole-water samples tested. Differences in percentage yields for the third synthetic whole-water sample were greater than 10 percent for 16 of the 26 elements determined. The USEPA method was the most rigorous for solubilizing elements from particulate matter in all three synthetic whole-water samples. Nevertheless, the variability in the percentage yield by using the USEPA digestion procedure was generally greater than the in-bottle digestion procedure, presumably because of the difficulty in controlling the digestion conditions accurately.

  19. Manual of procedures for the operation of bench-scale anaerobic digesters

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, R.R.

    1978-12-01

    The successful operation of any laboratory-scale biological system is often a difficult and frustrating experience. This is especially true when dealing with the anaerobic digestion process. Because of the stringent environmental requirements associated with anaerobic digesters, efficient operation of bench-scale units requires rigid monitoring and control. The purpose of this manual is to present the methods and procedures which are followed in bench-scale anaerobic digestion studies at Pacific Northwest Laboratory (PNL). Among the topics discussed are operating parameters, a description of the experimental system, typical digestion substrates, operational procedures, analytical techniques, and safety considerations. The document serves as a technical guide to PNL personnel assigned to a U.S. Department of Energy sponsored program evaluating the effect of powdered activated carbon on the anaerobic digestio of sewage sludge. It should be noted that the methods described in this manual do not necessarily represent the best or only means of conducting the research. They are merely procedures that have been found to be successful at PNL. It is hoped that this information may be useful to other researchers who are contemplating or pursuing bench-scale studies of their own.

  20. A qualitative and quantitative evaluation of the peptide characteristics of microwave- and ultrasound-assisted digestion in discovery and targeted proteomic analyses.

    Science.gov (United States)

    Guo, Zhengguang; Cheng, Jie; Sun, Haidan; Sun, Wei

    2017-08-30

    Fast digestion methods can dramatically accelerate enzyme digestion and increase the throughput of proteomic analysis. However, the peptide characteristics of fast digestion methods and their performance in discovery and targeted proteomic analysis must be systematically evaluated. Three digestion methods, including overnight digestion, microwave-assisted protein enzymatic digestion (MAPED), and high-intensity focused ultrasonic-assisted enzymatic digestion (HIFUSAED), in trypsin or in trypsin/Lys-C were comprehensively compared in both discovery and targeted proteomics analysis using the HeLa cell proteome. In discovery proteomic analysis, the highest numbers of peptides and proteins were identified when the sample was digested via the MAPED method with trypsin/Lys-C. The fast digestion methods showed a higher mis-cleavage rate and a lower semi-tryptic rate than the overnight digestion method. In both label-free quantitative analysis and targeted proteomic analysis, both fully cleaved peptides (FCPs) and mis-cleaved peptides (MCPs) from the fast digestion methods and the overnight digestion method showed good reproducibility if they showed good abundance. When both the FCPs and MCPs were included in the analysis, the MAPED with trypsin/Lys-C method showed the best results for both discovery proteomic analysis and relative quantitative targeted proteomic analysis. These results will be beneficial for the application of fast digestion methods to proteomics. Copyright © 2017 John Wiley & Sons, Ltd.

  1. [Simultaneous determination of cobalt and nickel in catalyst by microwave digestion-dual wavelength equal absorption spectrophotometry].

    Science.gov (United States)

    Li, L; Zhang, J; Gao, C

    2001-08-01

    Catalyst samples are digested in a microwave digestion system. The optimum parameters for microwave digestion are selected. Cobalt and nickel in the mixture of Co2+ and Ni2+ with 4-(2-pyridylazo) resorcinol (PAR) can be determined simultaneously by dual-wavelength equal absorption spectrophotometry. By means of the combination of two methods, Co2+ and Ni2+ in catalyst can be determined rapidly, accurately, and contamination problems avoided. The linear ranges are 0-30 micrograms.25 mL-1 for Co2+ and 0-25 micrograms.25 mL-1 for Ni2+. The recoveries of Co2+ and Ni2+ in synthetic samples are between 98.2%-103.6% and between 97.9%-103.7%, respectively. The relative standard deviations of analytical results in catalyst samples are less than 2.2% for Co2+ and less than 1.8% for Ni2+, and relative errors are less than +/- 2.5% for Co2+ and Ni2+.

  2. Accelerating Cosmic Microwave Background map-making procedure through preconditioning

    CERN Document Server

    Szydlarski, Mikolaj; Stompor, Radek

    2014-01-01

    Estimation of the sky signal from sequences of time ordered data is one of the key steps in Cosmic Microwave Background (CMB) data analysis, commonly referred to as the map-making problem. Some of the most popular and general methods proposed for this problem involve solving generalised least squares (GLS) equations with non-diagonal noise weights given by a block-diagonal matrix with Toeplitz blocks. In this work we study new map-making solvers potentially suitable for applications to the largest anticipated data sets. They are based on iterative conjugate gradient (CG) approaches enhanced with novel, parallel, two-level preconditioners. We apply the proposed solvers to examples of simulated non-polarised and polarised CMB observations, and a set of idealised scanning strategies with sky coverage ranging from nearly a full sky down to small sky patches. We discuss in detail their implementation for massively parallel computational platforms and their performance for a broad range of parameters characterising...

  3. 77 FR 28805 - Energy Conservation Program: Test Procedures for Microwave Ovens

    Science.gov (United States)

    2012-05-16

    ... Parts 429 and 430 RIN 1904-AB78 Energy Conservation Program: Test Procedures for Microwave Ovens AGENCY.... Authority and Background Title III of the Energy Policy and Conservation Act (42 U.S.C. 6291, et seq... essentially of four parts: (1) Testing, (2) labeling, (3) Federal energy conservation standards, and...

  4. Determination of metal concentrations in certified plastic reference materials after small-size autoclave and microwave-assisted digestion followed with inductively coupled plasma optical emission spectrometry

    Science.gov (United States)

    Lehtimäki, Esa; Väisänen, Ari

    2017-01-01

    The digestion methods for the determination of As, Cd, Cr, Pb, Sb, Sn and Zn concentrations in plastic samples using microwave-assisted digestion (MW-AD) and small-size autoclave digestion was developed. The certified polyethylene, polypropylene, polyvinyl chloride and acrylonitrile butadiene styrene certified reference materials were used in order to find digestion method working properly for several sample matrices. Efficiency of the digestion methods was evaluated by analyzing the residual carbon in digests by TOC analyzer. MW-AD using a mixture of 7 mL of HNO3 and 3 mL of H2O2 as a digestion solution resulted in excellent recoveries for As, Cd, Pb, Sb and Zn, and were in the range of 92-107% for all the analytes except Pb in polyethylene material. Autoclave digestion using 5 mL of concentrated HNO3 as a digestion solution resulted in similar recoveries with the exception of a higher As recovery (98%). Tin recovery resulted in low level after both MW-AD and autoclave digestion. Autoclave digestion was further developed resulting in a partially open two-step digestion process especially for the determination of Sn and Cr. The method resulted in higher recoveries of Sn and Cr (87 and 76%) but with the lower concentration of easily volatile As, Cd and Sb.

  5. Procedural sedation and analgesia in children undergoing digestive endoscopic procedures - paediatrician or anaesthesiologist?

    Science.gov (United States)

    Bartkowska-Śniatkowska, Alicja; Rosada-Kurasińska, Jowita; Ignyś, Iwona; Grześkowiak, Małgorzata; Zielińska, Marzena; Bienert, Agnieszka

    2014-01-01

    Endoscopic procedures of the gastrointestinal tract were successfully introduced into paediatric practice in the 1970s. Recent expansive development has become useful for improvement of both diagnosis and treatment in many children with gastrointestinal diseases. Most of these procedures are performed under procedural sedation (PSA) knowing anatomical, physiological and psychological differences and requiring good experience from the paediatrician and anaesthesiologist. These principles help to provide the procedure safely and minimise adverse events, which are greater the smaller the child is. Procedural sedation and analgesia in healthy children can be performed by a paediatrician, but children with congenital defects and serious coexisting diseases (ASA ≥ III) and also during the usage of anaesthetics (e.g. propofol), should be managed by an anaesthesiologist.

  6. Procedural sedation and analgesia in children undergoing digestive endoscopic procedures – paediatrician or anaesthesiologist?

    Science.gov (United States)

    Rosada-Kurasińska, Jowita; Ignyś, Iwona; Grześkowiak, Małgorzata; Zielińska, Marzena; Bienert, Agnieszka

    2014-01-01

    Endoscopic procedures of the gastrointestinal tract were successfully introduced into paediatric practice in the 1970s. Recent expansive development has become useful for improvement of both diagnosis and treatment in many children with gastrointestinal diseases. Most of these procedures are performed under procedural sedation (PSA) knowing anatomical, physiological and psychological differences and requiring good experience from the paediatrician and anaesthesiologist. These principles help to provide the procedure safely and minimise adverse events, which are greater the smaller the child is. Procedural sedation and analgesia in healthy children can be performed by a paediatrician, but children with congenital defects and serious coexisting diseases (ASA ≥ III) and also during the usage of anaesthetics (e.g. propofol), should be managed by an anaesthesiologist. PMID:25061486

  7. [Determination of thirty three elements in lung cancer tissues of patients with lung cancer by microwave digestion-ICP-MS].

    Science.gov (United States)

    Zhang, Lin-Lin; Ma, Qian-Li; Huang, Yun-Chao; Wu, Guo-Ping; Wei, Fu-Sheng

    2009-12-01

    A method for determining 33 elements in lung tissues of patients with lung cancer was developed by using vacuum freeze-drying microwave digestion-ICP-MS. The lung tissue samples were treated by vacuum freeze-drying equipment. After microwave digestion in HNO3-H2O2 solution system, the samples were diluted with the method of constant volume. Under the optimized conditions the samples were analyzed by ICP-MS. The double internal standard elements Rh and Re were used to compensate for matrix suppression effect and sensitivity drift. The analytical results showed that the detection limits of the 33 elements were 0.01-0.45 ng x mL(-1). The national standard reference material GBW(E)080193 bovine liver was analyzed by the described method and the measured element values accorded with the standard values or the reference values. The relative standard deviation (RSD) of the method was 2.1%-14.3%. The recovery rates of the studied elements were 90.1%-117.5%. The contents of 33 elements in lung cancer tissues, paracancerous lung tissues and benign lung tissues of 6 patients with lung cancer were determined by the method. It was indicated that the method is rapid, simple and accurate for determining multi-elements in human lung tissue and other biological samples.

  8. [Determination of 11 kinds of inorganic elements in Cortex Spondiacis by microwave digestion/ICP-MS method].

    Science.gov (United States)

    Luo, Wen; Ma, Jin-Jing; Zhang, Long-Wang; Chen, Cong; Ye, Yan-Qing

    2012-09-01

    The present research aimed to establish a kind of simple and rapid method to detect metal elements in Cortex Spondiacis were determined by microwave digestion and inductively coupled plasma mass spectrometry (ICP-MS). The sample was digested with HNO3-H2O2 acids system. The operation would be simplified and the blank value would be decreased with the above acids systems. Instead of using concent rated acid, this experiment not only can leave out the process of drying or dilution and save time, and extend the life of the instrument, but also eliminates the errors of the inconsistency between digestion solutions and standard solutions. The experimental results showed that Cortex Spondiacis is rich in beneficial elements such as potassium, calcium, magnesium, iron, sodium, and nickel. And the content of harmful elements of the drug, such as mercury, lead, cadmi um and arsenic, is under the national rule, which have some medicinal value. Under the optimum working conditions of the instrument, the detection limits were all smaller than 0.052 1 microg x L(-1), the recovery ratios by standard addition were in the range of 90.8%-113.8% and the RSD was smaller than 5.10% for all elements. Precision and accuracy of determining results are satisfactory. This results are reliable. These results are reliable. The method can meet the need for simultaneity determination of high content element and trace element in Cortex Spondiacis.

  9. Green procedure with a green solvent for fats and oils' determination. Microwave-integrated Soxhlet using limonene followed by microwave Clevenger distillation.

    Science.gov (United States)

    Virot, Matthieu; Tomao, Valérie; Ginies, Christian; Visinoni, Franco; Chemat, Farid

    2008-07-04

    Here is described a green and original alternative procedure for fats and oils' determination in oleaginous seeds. Extractions were carried out using a by-product of the citrus industry as extraction solvent, namely d-limonene, instead of hazardous petroleum solvents such as n-hexane. The described method is achieved in two steps using microwave energy: at first, extractions are attained using microwave-integrated Soxhlet, followed by the elimination of the solvent from the medium using a microwave Clevenger distillation in the second step. Oils extracted from olive seeds were compared with both conventional Soxhlet and microwave-integrated Soxhlet extraction procedures performed with n-hexane in terms of qualitative and quantitative determination. No significant difference was obtained between each extract allowing us to conclude that the proposed method is effective and valuable.

  10. In vitro starch digestibility and predicted glycemic index of microwaved and conventionally baked pound cake.

    Science.gov (United States)

    Sánchez-Pardo, María Elena; Ortiz-Moreno, Alicia; Mora-Escobedo, Rosalva; Necoechea-Mondragón, Hugo

    2007-09-01

    The present study compares the effect of baking process (microwave vs conventional oven) on starch bioavailability in fresh pound cake crumbs and in crumbs from pound cake stored for 8 days. Proximal chemical analysis, resistant starch (RS), retrograded starch (RS3) and starch hydrolysis index (HI) were evaluated. The empirical formula suggested by Granfeldt was used to determine the predicted glycemic index (pGI). Pound cake, one of Mexico's major bread products, was selected for analysis because the quality defects often associated with microwave baking might be reduced with the use of high-fat, high-moisture, batted dough. Differences in product moisture, RS and RS3 were observed in fresh microwave-baked and conventionally baked pound cake. RS3 increased significantly in conventionally baked products stored for 8 days at room temperature, whereas no significantly changes in RS3 were observed in the microwaved product. HI values for freshly baked and stored microwaved product were 59 and 62%, respectively (P > 0.05), whereas the HI value for the conventionally baked product decreased significantly after 8 days of storage. A pound cake with the desired HI and GI characteristics might be obtained by adjusting the microwave baking process.

  11. Anaerobic digestion of organic fraction of municipal solid waste combining two pretreatment modalities, high temperature microwave and hydrogen peroxide.

    Science.gov (United States)

    Shahriari, Haleh; Warith, Mostafa; Hamoda, Mohamed; Kennedy, Kevin J

    2012-01-01

    In order to enhance anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW), pretreatment combining two modalities, microwave (MW) heating in presence or absence of hydrogen peroxide (H(2)O(2)) were investigated. The main pretreatment variables affecting the characteristics of the OFMSW were temperature (T) via MW irradiation and supplemental water additions of 20% and 30% (SWA20 and SW30). Subsequently, the focus of this study was to evaluate mesophilic batch AD performance in terms of biogas production, as well as changes in the characteristics of the OFMSW post digestion. A high MW induced temperature range (115-175°C) was applied, using sealed vessels and a bench scale MW unit equipped with temperature and pressure controls. Biochemical methane potential (BMP) tests were conducted on the whole OFMSW as well as the liquid fractions. The whole OFMSW pretreated at 115°C and 145°C showed 4-7% improvement in biogas production over untreated OFMSW (control). When pretreated at 175°C, biogas production decreased due to formation of refractory compounds, inhibiting the digestion. For the liquid fraction of OFMSW, the effect of pretreatment on the cumulative biogas production (CBP) was more pronounced for SWA20 at 145°C, with a 26% increase in biogas production after 8days of digestion, compared to the control. When considering the increased substrate availability in the liquid fraction after MW pretreatment, a 78% improvement in biogas production vs. the control was achieved. Combining MW and H(2)O(2) modalities did not have a positive impact on OFMSW stabilization and enhanced biogas production. In general, all samples pretreated with H(2)O(2) displayed a long lag phase and the CBP was usually lower than MW irradiated only samples. First order rate constant was calculated.

  12. Application of ICP-AES with Microwave Digestion to Detect Trace Elements in Oysters from Jiaozhou Bay, China

    Institute of Scientific and Technical Information of China (English)

    ZHENG Kang; YAN Cuiwei

    2011-01-01

    A Using ICP-AES with microwave digestion,we determined the concentrations of 16 trace elements in oysters from six sampling points in Jiaozhou Bay.The distributions of the wholesome elements Zn,Fe and Mn,and heavy metals such as As,Cd,Hg and Pb were studied.The oysters collected are all rich in the wholesome trace elements,and the oysters from Licun River have the highest concentrations of the three wholesome trace elements.The concentrations of heavy metals in oysters from Licun River are the highest and those from Hongdao are the lowest.Compared with the domestic and foreign sea-areas,the heavy metal contents in the oysters from Jiaozhou Bay are less in amount than those from some developed countries,and more than those in Southeast China.This implies that the Jiaozhou Bay's oysters have been polluted by the environment to some extent.

  13. Determination of cadmium by electrothermal atomic absorption spectrometry after microwave-assisted digestion of animal tissues and sewage sludges.

    Science.gov (United States)

    Chakraborty, R; Das, A K; Cervera, M L; De La Guardia, M

    1996-04-01

    The determination of cadmium in different sample types has been carried out by electrothermal atomization atomic absorption spectrometry with D(2)-background correction using a unpyrocoated graphite tube, after pressurized microwave-assisted digestion. Five chemical modifiers [(NH(4))(2)HPO(4), Pd(NO)(3))(2), Ni(NO(3))(2), thiourea and Triton X-100] have been assayed and nickel nitrate has been found to be most effective for an accurate determination of cadmium in mussel tissue, pig kidney and sewage sludge. The characteristic mass of the method is of the order of 1 pg and the limit of detection is lower than 0.1 ng/ml.

  14. An effective procedure for MNP-enhanced breast cancer microwave imaging.

    Science.gov (United States)

    Scapaticci, Rosa; Bellizzi, Gennaro; Catapano, Ilaria; Crocco, Lorenzo; Bucci, Ovidio Mario

    2014-04-01

    Magnetic nanoparticles-enhanced microwave imaging has been recently proposed to overcome the limitations of conventional microwave imaging methods for breast cancer monitoring. In this paper, we discuss how to tackle the linear inverse scattering problem underlying this novel technique in an effective way. In particular, our aim is to minimize the required a priori patient-specific information, avoid occurrence of false positives, and keep the computational burden low. By relying on an extensive numerical analysis in realistic conditions, we show that the method can provide accurate and reliable images without information on the inner structure of the inspected breast and with an only rough knowledge of its shape. Notably, this allows moving to an offline stage the computationally intensive part of the image formation procedure. In addition, we show how to appraise the total amount of magnetic contrast agent targeted in the tumor.

  15. Distribution of the elements in cotyledon, embryonic axis, and testa of peanut seeds obtained by ICP-MS with microwave acid digestion.

    Science.gov (United States)

    Zhu, Yanbei; Hioki, Akiharu; Chiba, Koichi

    2013-01-01

    Eighteen elements in the cotyledon, the embryonic axis, and the testa of peanut seeds were determined by inductively coupled plasma mass spectrometry (ICP-MS) after microwave acid digestion, while the gravimetric standard addition with internal standard was applied for the calibration of the elemental concentrations. The detection limit and the procedure blank value for each element were low enough to ensure the precise analysis of the elements, with a relative expanded uncertainty of less than 5%. The concentrations of the elements in peanut seed samples covered 6 orders of magnitude from approximately 0.01 mg kg(-1) of Co to approximately 7000 mg kg(-1) of K. The correlation coefficient factor was around 0.98 for the elemental concentrations in peanut seeds grown in Japan and those grown in China, indicating a good correlation. Most of the elements distributed in the cotyledon in large amounts because of the cotyledon's relatively high mass fraction. By contrast, Na, Ca, Fe, Co, Ni, Cu, Ga, Sr, Cd, and Ba were apparently enriched in the testa and the relative enrichment factor (REF) values of the elements were over 4. The relative enrichment of Mo, Fe, Zn and other elements was observed in the embryonic axis samples with REF values over 2. The relative enrichment of Cd in the testa of peanut seed indicates that about 15 to 25% of the Cd intake through peanut seeds could be effectively lowered by removal of the testa (roughly 2.5 to 3.5% of the peanut seed).

  16. Development of a microwave-assisted digestion method using ICP-OES to measure metals in gum deposits of internal combustion engines

    Energy Technology Data Exchange (ETDEWEB)

    Dantas, Allan N.S.; Costa, Rouse S.; Gouveia, Sandro T.; Lopes, Gisele S. [Departamento de Quimica Analitica e Fisico-Quimica, Universidade Federal do Ceara, Fortaleza, CE (Brazil)

    2010-11-15

    The heterogeneous nature of gum samples obtained from the deposits of internal combustion engines is the main difficulty in accurate determination of their metal content. A microwave-assisted digestion method was implemented using factorial experimental design. The optimization of this procedure was carried out by first evaluating the effects of variables on the response (i.e., the residual carbon content or RCC). The variables of maximum heating power, heating time and nitric acid volume were studied. The RCC response was measured by inductively coupled plasma optical emission spectrometry (ICP-OES). The time of maximum heating power was essential to obtain a desired RCC. The surface response was constructed with optimal conditions presented at 6 min and heating power of 700 W. Amounts of aluminum (Al), calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn) were determined in 26 gum samples by ICP-OES. Ca, Fe, Mg and Zn were found at mg g{sup -1} levels in the samples, while Al, Cu, Mn, Ni and Pb were found at mg kg{sup -1} levels. Principal component analysis (PCA) was used to establish a correlation between the gum samples and the different metal contents. Three distinct groups were separated according to the characteristics of the collected samples. (author)

  17. Determination of platinum in waste platinum-loaded carbon catalyst samples using microwave-assisted sample digestion and ICP-OES

    Science.gov (United States)

    Ma, Yinbiao; Wei, Xiaojuan

    2017-04-01

    A novel method for the determination of platinum in waste platinum-loaded carbon catalyst samples was established by inductively coupled plasma optical emission spectrometry after samples digested by microwave oven with aqua regia. Such experiment conditions were investigated as the influence of sample digestion methods, digestion time, digestion temperature and interfering ions on the determination. Under the optimized conditions, the linear range of calibration graph for Pt was 0 ˜ 200.00 mg L-1, and the recovery was 95.67% ˜ 104.29%. The relative standard deviation (RSDs) for Pt was 1.78 %. The proposed method was applied to determine the same samples with atomic absorption spectrometry with the results consistently, which is suitable for the determination of platinum in waste platinum-loaded carbon catalyst samples.

  18. Procedures for identifying infectious prions after passage through the digestive system of an avian species.

    Science.gov (United States)

    Fischer, Justin W; Nichols, Tracy A; Phillips, Gregory E; VerCauteren, Kurt C

    2013-11-06

    Infectious prion (PrP(Res)) material is likely the cause of fatal, neurodegenerative transmissible spongiform encephalopathy (TSE) diseases(1). Transmission of TSE diseases, such as chronic wasting disease (CWD), is presumed to be from animal to animal(2,3) as well as from environmental sources(4-6). Scavengers and carnivores have potential to translocate PrP(Res) material through consumption and excretion of CWD-contaminated carrion. Recent work has documented passage of PrP(Res) material through the digestive system of American crows (Corvus brachyrhynchos), a common North American scavenger(7). We describe procedures used to document passage of PrP(Res) material through American crows. Crows were gavaged with RML-strain mouse-adapted scrapie and their feces were collected 4 hr post gavage. Crow feces were then pooled and injected intraperitoneally into C57BL/6 mice. Mice were monitored daily until they expressed clinical signs of mouse scrapie and were thereafter euthanized. Asymptomatic mice were monitored until 365 days post inoculation. Western blot analysis was conducted to confirm disease status. Results revealed that prions remain infectious after traveling through the digestive system of crows and are present in the feces, causing disease in test mice.

  19. Microwave-assisted ultraviolet digestion of petroleum coke for the simultaneous determination of nickel, vanadium and sulfur by ICP-OES.

    Science.gov (United States)

    Oliveira, Jussiane S S; Picoloto, Rochele S; Bizzi, Cezar A; Mello, Paola A; Barin, Juliano S; Flores, Erico M M

    2015-11-01

    A method for the simultaneous determination of Ni, V and S in petroleum coke by inductively coupled plasma optical emission spectrometry (ICP-OES) after microwave-assisted ultraviolet digestion (MW-UV) in closed vessels was proposed. Digestion was performed using electrodeless discharge lamps positioned inside quartz vessels and turned on by microwave radiation. The following parameters were evaluated: HNO3 concentration (15 mL of 1, 4, 7, 10 or 14.4 mol L(-1)), volume of H2O2 (30%, 1 or 3 mL), sample mass (100, 250 or 500 mg) and heating time (40 or 60 min) with or without the use of UV lamps. Digestion efficiency was evaluated by the determination of the residual carbon content (RCC) in digests. Using UV lamps lower RCC was obtained and the combination of 4 mol L(-1) HNO3 with 3 mL of H2O2 and 60 min of heating allowed a suitable digestion of up to 500 mg of petroleum coke (RCCdigestion of petroleum coke by microwave-induced combustion) and with a certified reference material of petroleum coke was between 96 and 101%. The proposed method was considered as advantageous when compared to American Society for Testing and Materials method because it allowed the simultaneous determination of Ni, V and S with lower limit of detection (0.22, 0.12 and 8.7 µg g(-1) for Ni, V and S, respectively) avoiding the use of concentrated nitric acid and providing digests suitable for routine analysis by ICP-OES.

  20. 超声波辅助微波消解预处理测量污泥金属元素%Measuring Metal Elements in Sludge with Ultrasound-assisted Microwave Digestion Pretreatment

    Institute of Scientific and Technical Information of China (English)

    李洪波; 唐然; 周从直; 龙向宇

    2014-01-01

    By adopting laboratory sludge and sewage sludge as objects, a method and process of measuring metal elements with ultrasound-assisted microwave digestion pretreatment is researched. First, sludge flocs are dispered by ultrasound. Then they are pretreated by heat and disgested. Last mental elemeats are measured by using atomic absorption. The results show that the opti-mal conditions of ultrasonic treatment are 150 W in 3 min for 25 mL sludge, which can ensure well-distributed sampling in the fol-lowing procedure. Before microwave digestion, the suitable condition of heating pretreatment is 20 min at 90℃, the optimal acid of microwave digestion for laboratory sludge is 2 mL hydrogen peroxide with 4 mL anti aqua regia (or 4 mL aqua regia), while the opti-mal acid system of microwave digestion for actual sewage sludge is 1 mL hydrofluoric acid, 2 mL hydrogen peroxide and 4 mL aqua regia, of which the third digestion procedure is 20 min at 2.0 MPa. Ultrasound-assisted microwave digestion pretreatment has some advantages, such as saving acid, simplicity, high precision and accuracy, with which the relative standard deviation of measuring K, Ca, Mg, Fe in sludge is lower than 2.75%, and the recovery is 97.5%-102%.%以实验室污泥和污水厂污泥为研究对象,建立了超声波辅助微波消解预处理测量污泥金属元素的方法与程序。首先通过超声波分散污泥絮体,然后对污泥进行加热预处理和微波消除,最后采用火焰原子吸收法测量污泥中的金属元素。结果表明,150 W超声波作用于25 mL污泥3 min为超声波分散污泥的较优条件,能保证后续操作过程取样均匀。微波消解前适宜的加热预处理条件为90℃,20 min。实验室污泥微波消解的较优酸体系为2 mL双氧水+4 mL反王水(或4 mL王水);污水厂污泥微波消解的较优酸体系为1 mL氢氟酸+2 mL双氧水+4 mL王水,同时,第3阶段消解条件为压强2.0 MPa下消解20 min。超声

  1. Selection of Digestion Solution for Determining Zn in Soil by Microwave Digestion-FAAS%微波消解原子分光光度法测定土壤中锌含量消解液的筛选

    Institute of Scientific and Technical Information of China (English)

    耿昭克

    2016-01-01

    Objective] To select the optimal digestion solution for determining Zn in soil by microwave digestion – FAAS.[Methods] micro-wave digestion –FAAS was applied.Hydrochloric acid +nitric acid +hydrofluoric acid and hydrochloric acid +nitric acid +hydrogen per-oxide solution were taken as digestion solution separately.And comparative analysis experiment was carried.[Results] In the process of determi-ning Zn in soil by microwave digestion – FAAS, the digestion was complete when using hydrochloric acid +nitric acid +hydrofluoric acid as digestion solution, but the absorbance was abnormal and irregularity was high, leading to failure of the experiment; hydrochloric acid +nitric acid +hydrogen peroxide solution as the digestion solution could dissolve most Zn element in soil and satisfy the analysis requirement .[ Conclu-sion] Taking hydrochloric acid +nitric acid +hydrogen peroxide solution as the digestion solution meets requirement of analysis precision in determining the soil Zn content.%[目的]筛选微波消解原子分光光度法测定土壤中锌含量的最优消解液。[方法]采用微波消解原子分光光度法测定土壤中锌含量,分别用盐酸+硝酸+氢氟酸、盐酸+硝酸+双氧水作为消解液,对土壤样品进行微波消解,通过对比分析试验,优化合适的消解液。[结果]微波消解原子分光光度法测定土壤锌含量过程中,采用盐酸+硝酸+氢氟酸消解液,消解较为完全,但是吸光度异常、无规律偏高,导致试验失败;盐酸+硝酸+双氧水消解液,能溶解土壤中大部分锌元素,满足分析要求。[结论]采用盐酸+硝酸+双氧水作为消解液测定土壤锌含量满足分析精度要求。

  2. Digestión en horno de microondas para determinación de contenido de hierro y zinc totales en alimentos Microwave digestion for determination of iron and zinc content of total food

    Directory of Open Access Journals (Sweden)

    Paulina Silva Trejos

    2012-11-01

    Full Text Available En el presente estudio se optimizó el procedimiento de digestión de alimentos por medio de un horno de microondas, para cuantificar el hierro y el zinc totales en diferentes matrices por espectroscopía de absorción atómica. Se analizó la cantidad óptima de HNO3 concentrado al 65% para digerir determinada masa de muestra por evaluación del porcentaje de recuperación obtenido con diferente cantidad de HNO3. Los resultados no difieren de los obtenidos por los métodos recomendados oficialmente de digestión ácida en sistemas abiertos y de calcinación.In this study, the procedure was optimized digestion of food by means of a microwave oven, to quantify the total iron and zinc in different matrices by atomic absorption spectroscopy. We analyzed the optimal amount of 65% concentrated HNO3 to digest sample mass determined by evaluating the percent recover y obtained with different amounts of HNO3.The results are similar to those obtained by the methods recommended officially acid digestion in open systems and calcination.

  3. Effect of simultaneous cooling on microwave-assisted wet digestion of biological samples with diluted nitric acid and O{sub 2} pressure

    Energy Technology Data Exchange (ETDEWEB)

    Bizzi, Cezar A. [Departamento de Química, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul 97105-900 (Brazil); Nóbrega, Joaquim A. [Departamento de Química, Universidade Federal de São Carlos, São Carlos, São Paulo 13565-905 (Brazil); Barin, Juliano S. [Departamento de Tecnologia e Ciência dos Alimentos, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul 97105-900 (Brazil); Oliveira, Jussiane S.S.; Schmidt, Lucas; Mello, Paola A. [Departamento de Química, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul 97105-900 (Brazil); Flores, Erico M.M., E-mail: ericommf@gmail.br [Departamento de Química, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul 97105-900 (Brazil)

    2014-07-21

    Highlights: • Simultaneously cooling during microwave heating for improving digestion efficiency. • Maximum MW power delivered into cavity, improving the temperature in liquid phase. • Temperature gradient increases regeneration reaction of HNO{sub 3} in O{sub 2} rich atmosphere. • Digestion of several matrices using diluted HNO{sub 3} combined with O{sub 2} pressure. - Abstract: The present work evaluates the influence of vessel cooling simultaneously to microwave-assisted digestion performed in a closed system with diluted HNO{sub 3} under O{sub 2} pressure. The effect of outside air flow-rates (60–190 m{sup 3} h{sup −1}) used for cooling of digestion vessels was evaluated. An improvement in digestion efficiency caused by the reduction of HNO{sub 3} partial pressure was observed when using higher air flow-rate (190 m{sup 3} h{sup −1}), decreasing the residual carbon content for whole milk powder from 21.7 to 9.3% (lowest and highest air flow-rate, respectively). The use of high air flow-rate outside the digestion vessel resulted in a higher temperature gradient between liquid and gas phases inside the digestion vessel and improved the efficiency of sample digestion. Since a more pronounced temperature gradient was obtained, it contributed for increasing the condensation rate and thus allowed a reduction in the HNO{sub 3} partial pressure of the digestion vessel, which improved the regeneration of HNO{sub 3}. An air flow-rate of 190 m{sup 3} h{sup −1} was selected for digestion of animal fat, bovine liver, ground soybean, non fat milk powder, oregano leaves, potato starch and whole milk powder samples, and a standard reference material of apple leaves (NIST 1515), bovine liver (NIST 1577) and whole milk powder (NIST 8435) for further metals determination by inductively coupled plasma atomic emission spectroscopy (ICP-OES). Results were in agreement with certified values and no interferences caused by matrix effects during the determination step

  4. [Determination of trace heavy metal elements in cortex Phellodendron chinense by ICP-MS after microwave-assisted digestion].

    Science.gov (United States)

    Kou, Xing-Ming; Xu, Min; Gu, Yong-Zuo

    2007-06-01

    An inductively coupled plasma mass spectrometry (ICP-MS) for determination of the contents of 8 trace heavy metal elements in cortex Phellodendron chinense after microwave-assisted digestion of the sample has been developed. The accuracy of the method was evaluated by the analysis of corresponding trace heavy metal elements in standard reference materials (GBW 07604 and GBW 07605). By applying the proposed method, the contents of 8 trace heavy metal elements in cortex Phellodendron chinense cultivated in different areas (in Bazhong, Yibin and Yingjing, respectively) of Sichuan and different growth period (6, 8 and 10 years of samples from Yingjing) were determined. The relative standard deviation (RSD) is in the range of 3.2%-17.8% and the recoveries of standard addition are in the range of 70%-120%. The results of the study indicate that the proposed method has the advantages of simplicity, speediness and sensitivity. It is suitable for the determination of the contents of 8 trace heavy metal elements in cortex Phellodendron chinense. The results also show that the concentrations of 4 harmful trace heavy metal elements As, Cd, Hg and Pb in cortex Phellodendron chinense are all lower than the limits of Chinese Pharmacopoeia and Green Trade Standard for Importing and Exporting Medicinal Plant and Preparation. Therefore, the cortex Phellodendron chinense is fit for use as medicine and export.

  5. Evaluation of Trace Metal Content by ICP-MS Using Closed Vessel Microwave Digestion in Fresh Water Fish

    Directory of Open Access Journals (Sweden)

    Sreenivasa Rao Jarapala

    2014-01-01

    Full Text Available The objective of the present study was to investigate trace metal levels of different varieties of fresh water fish using Inductively Coupled Plasma Mass Spectrophotometer after microwave digestion (MD-ICPMS. Fish samples were collected from the outlets of twin cities of Hyderabad and Secunderabad. The trace metal content in different varieties of analyzed fish were ranged from 0.24 to 1.68 mg/kg for Chromium in Cyprinus carpio and Masto symbollon, 0.20 to 7.52 mg/kg for Manganese in Labeo rohita and Masto symbollon, 0.006 to 0.07 mg/kg for Cobalt in Rastrelliger kanagurta and Pampus argenteus, 0.31 to 2.24 mg/kg for Copper in Labeo rohita and Penaeus monodon, 3.25 to 14.56 mg/kg for Zinc in Cyprinus carpio and Macrobrachium rosenbergii, and 0.01 to 2.05 mg/kg for Selenium in Rastrelliger kanagurta and Pampus argenteus, respectively. Proximate composition data for the different fishes were also tabulated. Since the available data for different trace elements for fish is scanty, here an effort is made to present a precise data for the same as estimated on ICP-MS. Results were in accordance with recommended daily intake allowance by WHO/FAO.

  6. [Determination of trace elements in Lophatherum gracile brongn from different habitat by microwave digestion-atomic absorption spectroscopy].

    Science.gov (United States)

    Yuan, Ke; Xue, Yue-Qin; Gui, Ren-Yi; Sun, Su-Qin; Yin, Ming-Wen

    2010-03-01

    A method of microwave digestion technique was proposed to determine the content of Zn, Fe, Cu, Mn, K, Ca, Mg, Ni, Cd, Pb, Cr, Co, Al, Se and As in Lophatherum gracile brongn of different habitat by atomic absorption spectroscopy. The RSD of the method was between 1.23% and 3.32%, and the recovery rates obtained by standard addition method were between 95.8% and 104.20%. The results of the study indicate that the proposed method has the advantages of simplicity, speediness and sensitivity. It is suitable for the determination of the contents of metal elements in Lophatherum gracile brongn. The experimental results also indicated that different areas' Lophantherum gracile brongn had different trace elements content. The content of trace elements K, Mg, Ca, Fe and Mn beneficial to the human body was rich. The content of the heavy metal trace element Pb in Lophantherum gracile brongn of Hunan province was slightly high. The content of the heavy metal trace element Cu in Lophantherum gracile brongn of Guangdong province and Anhui province is also slightly higher. Beside, the contents of harmful trace heavy metal elements Cd, Cu, Cr, Pb and As in Lophatherum gracile brongn of different habitat are all lower than the limits of Chinese Pharmacopoeia and Green Trade Standard for Importing and Exporting Medicinal Plant and Preparation and National Food Sanitation Standard. These determination results provided the scientific data for further discussing the relationship between the content of trace elements in Lophantherum gracile brongn and the medicine efficacy.

  7. Comparison of three digestion techniques for the determination of lead in baby food; Etude comparative de trois procedes de mineralisation pour le dosage du plomb dans les denrees alimentaires pour bebes

    Energy Technology Data Exchange (ETDEWEB)

    Parmigiani, M.; Midio, A. [Sao Paulo Universidade, Setor de Toxicologia, Faculdade de Ciencias Farmaceuticas, Sao Paulo (Brazil)

    1997-03-01

    In this paper the results obtained using microwave, dry ashing and wet digestion procedures on baby food samples for the detection of lead are compared. The determination of the element was performed using a graphite furnace atomic absorption spectrometer. This study showed that of the three digestion procedures dry ashing produced the more precise results; wet ashing and microwave digestion exhibited the best recovery values for certified reference material (100% and 116% respectively). Microwave digestion offers advantages over the two conventional ashing techniques. (authors) 26 refs.

  8. Determination of total phosphorus-microwave digestive a mmonium molybdate spectrophotometric method%微波消解钼酸铵分光光度法测定水中总磷

    Institute of Scientific and Technical Information of China (English)

    俞丹梅

    2001-01-01

    Microwave digesting has been paid close attention as a new technology to process samples in advance. In this article,we discuss th e application of microwave digest to the determination of total phosphorus. C ompared with traditional digestion method,microwave digesting has high precision and a ccuracy,and especially,it saves time and power.%微波消解作为样品预处理的新技术已受到普 遍关 注,作者讨论了微波消解在总磷测定中的应用,该法较传统消解法省时、省电,具有良好的 精密度和准确度。

  9. Determination of several elements in duplicate meals from catering establishments using closed vessel microwave digestion with inductively coupled plasma mass spectrometry detection: estimation of daily dietary intake.

    Science.gov (United States)

    Noël, L; Leblanc, J C; Guérin, T

    2003-01-01

    An estimation of the dietary exposure of French consumers to 21 essential and non-essential mineral elements using duplicate meals (breakfast and lunch) purchased from catering establishments was investigated after digestion by a closed vessel microwave procedure and quantification by ICP-MS. Daily dietary exposure estimates for metals and minerals were compared with the Provisional Tolerable Weekly Intakes (PTWI), the Tolerable Daily Intake (TDI) or the Acceptable Daily Intakes (ADI), as established by the FAO/WHO to estimate the risk of toxicity, and the US Recommended Daily Allowances (US RDA) or the Estimate Safe & Adequate Daily Dietary Intakes (ESADDI). Moreover, comparisons were made with those from previous French studies as well as those from other countries. The estimated mean daily intakes were 11 microgram for lithium, 3.42 g for sodium, 192 mg for magnesium, 2.03 mg for aluminium, 3.64 g for potassium, 642 mg for calcium, 154 microgram for chromium, 12.3 mg for iron, 2.15 mg for manganese, 4 microgram for cobalt, 74 microgram for nickel, 925 microgram for copper, 10.2 mg for zinc, 147 microgram for arsenic, 66 microgram for selenium, 112 microgram for molybdenum, 3.6 microgram for cadmium, 2.32 mg for tin, 3 microgram for antimony, 9 microgram for mercury and 34 microgram for lead. For the non-essential (toxic) elements, aluminium, tin, antimony, cadmium, arsenic, mercury and lead, the daily intake estimates were far below tolerable limits; and similar or somewhat lower than their respective PTWI, ADI, TDI, ESADDI and US RDA for individual minerals and essential trace elements, with good agreement with other country studies. The performance of the multi-elemental ICP-MS technique was also evaluated.

  10. 77 FR 33106 - Energy Conservation Program: Test Procedure for Microwave Ovens

    Science.gov (United States)

    2012-06-05

    ... on a review of the cooking manuals and recipe books supplied with convection microwave ovens that a... books supplied with convection microwave ovens, DOE noted that a majority of the recipes that used... contained in the cooking manuals and recipe books supplied with convection microwave ovens. Based...

  11. [Determination of inorganic elements in five kinds of Mongolia medicines by high pressure sealed microwave digestion-ICP-AES].

    Science.gov (United States)

    Sagara; Zhaorigetu; Dong, Guo-Liang; Zhang, Jing-Xia

    2008-07-01

    Five kinds of Mongolia medicines, Eridun-Urile, Deduhonghuaqiweiwan, Tonglage-5, Uzhumu-7 and Geiwang-9 are digested with HNO3-HClO4 system by high pressure system-sealed Microwave Digestion. The 17 inorganic elements content of magnesium, aluminum, calcium, chromium, manganese, ferrum, cobalt, nickel, copper, zincum, arsenic, selenium, strontium, molybdenum, silver, cadmium, plumbum in the solution are determined by ICP-AES. The results are proved to be reliable by adding standard recovery experiment. The recovery is 97.48%-103.01% for Mg, 102.71%-105.60% for Al, 102.00%-105.53% for Ca, 98.78%-100.34% for Cr, 101.93%-104.65% for Mn, 100.34%-104.51% for Fe, 103.13%-105.46% for Co, 100.07%-103.22% for Ni, 97.25%-99.06% for Cu, 98.57%-100.10% for Zn, 102.35%-105.37% for As, 100.24%-104.59% for Se, 99.19%-102.70% for Sr, 103.35%-105.78% for Mo, 99.65%-101.32% for Ag, 102.73%-105.32% for Cd, and 104.76%-106.35% for Pb by this method. The relative standard deviation is less than 3.3% for all the elements. And the method has high accuracy and good precision The determination results indicate that the content of element in Five Kinds of Mongolia Medicines is 0-15 microg x g(-1) for Cd, Ag, As, Pb, Co, Ni, Cu; 15-100 microg x g(-1) for Mo, Se, Zn, Cr; 100-3 000 microg x g(-1) for Mn, Sr, Fe, Mg, Al; 3 000-8 000 microg x g(-1) for Ca. Among of the five kinds of mongolia medicines, the content of elements has great differences. The order is Ca > Mg > Al > Fe > Mn > Sr > Se > Zn > Mo > Cu > Pb > As >Cr > Ni > Co > Cd > Ag for Eridun-Urile; Ca > Al > Fe > Mg > Mn > Sr > Se > Mo > Zn > Ni > Cr > Cu > Pb > As > Co > Cd > Ag for Deduhonghuaqiweiwan; Ca > Fe > Mg > Al > Mn > Sr > Se > Zn > Mo > Cr > Ni > Cu > Pb > As > Co > Cd > Ag for Tonglage-5, Ca > Al > Mg > Fe > Sr > Mn > Se > Zn > Co > Mo > Cr > Cu > Pb > As > Ag > Ni > Cd for Uzhumu-7 and Mg > Ca > Al > Fe > Se > Mn > Zn > Sr > Mo > Cu > Cr > Pb >As > Ag > Co = Cd = Ni for Geiwang-9. The content of common elements Ca, Mg

  12. Use of microwave digestion for estimation of heavy metal content of soils in a geochemical survey.

    Science.gov (United States)

    McGrath, D

    1998-07-01

    A procedure for the rapid and safe analysis of soils with widely differing organic matter contents has been investigated and validated. Surface soils, totalling 295 and sampled on a grid basis, representing 22% of the land-base of the Republic of Ireland, have been analysed for cadmium, chromium, copper, nickel, lead and zinc. Soil concentrations of cadmium, chromium, lead and nickel exhibit patterns of regionalised elevation. Implications of this elevation are considered in relation to sewage sludge application to land, future requirement for baseline surveys and concerns over concentrations in food products.

  13. Low gas flow inductively coupled plasma optical emission spectrometry for the analysis of food samples after microwave digestion.

    Science.gov (United States)

    Nowak, Sascha; Gesell, Monika; Holtkamp, Michael; Scheffer, Andy; Sperling, Michael; Karst, Uwe; Buscher, Wolfgang

    2014-11-01

    In this work, the recently introduced low flow inductively coupled plasma optical emission spectrometry (ICP-OES) with a total argon consumption below 0.7 L/min is applied for the first time to the field of food analysis. One goal is the investigation of the performance of this low flow plasma compared to a conventional ICP-OES system when non-aqueous samples with a certain matrix are introduced into the system. For this purpose, arsenic is determined in three different kinds of fish samples. In addition several nutrients (K, Na, Mg, Ca) and trace metals (Co, Cu, Mn, Cd, Pb, Zn, Fe, and Ni) are determined in honey samples (acacia) after microwave digestion. The precision of the measurements is characterized by relative standard deviations (RSD) and compared to the corresponding precision values achieved using the conventional Fassel-type torch of the ICP. To prove the accuracy of the low flow ICP-OES method, the obtained data from honey samples are validated by a conventional ICP-OES. For the measurements concerning arsenic in fish, the low flow ICP-OES values are validated by conventional Fassel-type ICP-OES. Furthermore, a certified reference material was investigated with the low gas flow setup. Limits of detection (LOD), according to the 3σ criterion, were determined to be in the low microgram per liter range for all analytes. Recovery rates in the range of 96-106% were observed for the determined trace metal elements. It was proven that the low gas flow ICP-OES leads to results that are comparable with those obtained with the Fassel-type torch for the analysis of food samples.

  14. Influence of Continuous Flow Microwave Pre-Treatment on Anaerobic Digestion of Secondary Thickened Sludge for Sustainable Energy Recovery in Sewage Treatment Plant

    Science.gov (United States)

    Hephzibah, D.; Kumaran, P.; Saifuddin, N. M.

    2016-03-01

    This work elucidates the effects of pre-treatment of secondary thickened sludge (STS) for enhancement of biogas production that has great potential to generate energy for the utilization of the sewage treatment plant (STP) itself. Microwave pre-treatment has been adopted for this study. Experiment works have been designed and conducted to examine the effectiveness of continuous flow microwave pre-treatment on the solubility of STS, digestibility of STS and biogas production at a power level of 80 W for 5, 10 and 15 minutes. A few characteristics of the sewage sludge were monitored daily to identify the effect of pre-treatment on the sludge. The soluble chemical oxygen demand (SCOD)/total chemical oxygen demand (TCOD) ratio increased by 0.1, 1.0 and 1.8%, while the volatile fatty acids (VFA) concentration of the pre-treated sludge improved by 4.4, 5.1, 5.9% at the irradiation time of 5, 10 and 15 minutes, respectively at a microwave power level of 80 W. Besides that, the digestate also indicates that the pre-treated sludge undergoes efficient VS removal and TCOD removal after anaerobic digestion compared to the untreated sludge. Moreover, the biogas quantity increased by an average of 19.2, 24.1 and 32.2% in 5, 10 and 15 minutes irradiation time respectively compared to the untreated sludge. The additional quantity of biogas generated has shown a great potential for sustainable energy generation that can be utilized internally by the STP.

  15. In vitro starch digestibility and expected glycemic index of pound cakes baked in two-cycle microwave-toaster and conventional oven.

    Science.gov (United States)

    García-zaragoza, Francisco J; Sánchez-Pardo, María E; Ortiz-Moreno, Alicia; Bello-Pérez, Luis A

    2010-11-01

    Bread baking technology has an important effect on starch digestibility measured as its predicted glycemic index tested in vitro. The aim of this work was to evaluate the changes in predicted glycemic index of pound cake baked in a two-cycle microwave toaster and a conventional oven. The glycemic index was calculated from hydrolysis index values by the Granfeldt method. Non-significant differences (P > 0.05) were found in hydrolysis index (60.67 ± 3.96 for the product baked in microwave oven and 65.94 ± 4.09 for the product baked in conventional oven) and predicted glycemic index content (60.5 for product baked in microwave oven and 65 for the product baked in conventional oven) in freshly-baked samples. Results clearly demonstrate that the baking pound cake conventional process could be replicated using a two-cycle multifunction microwave oven, reducing the traditional baking time. Further research is required in order to achieve pound cake crumb uniformity.

  16. Identification procedures for the charge-controlled nonlinear noise model of microwave electron devices

    Science.gov (United States)

    Filicori, Fabio; Traverso, Pier Andrea; Florian, Corrado; Borgarino, Mattia

    2004-05-01

    The basic features of the recently proposed Charge-Controlled Non-linear Noise (CCNN) model for the prediction of low-to-high-frequency noise up-conversion in electron devices under large-signal RF operation are synthetically presented. It is shown that the different noise generation phenomena within the device can be described by four equivalent noise sources, which are connected at the ports of a "noiseless" device model and are non-linearly controlled by the time-varying instantaneous values of the intrinsic device voltages. For the empirical identification of the voltage-controlled equivalent noise sources, different possible characterization procedures, based not only on conventional low-frequency noise data, but also on different types of noise measurements carried out under large-signal RF operating conditions are discussed. As an example of application, the measurement-based identification of the CCNN model for a GaInP heterojunction bipolar microwave transistor is presented. Preliminary validation results show that the proposed model can describe with adequate accuracy not only the low-frequency noise of the HBT, but also its phase-noise performance in a prototype VCO implemented by using the same monolithic GaAs technology.

  17. Simultaneous determination of bromine and iodine in milk powder for adult and infant nutrition by plasma based techniques after digestion using microwave-induced combustion

    Energy Technology Data Exchange (ETDEWEB)

    Picoloto, Rochele S. [Núcleo de Química, Universidade Tecnológica Federal do Paraná, 85884-000 Medianeira, PR (Brazil); Doneda, Morgana [Departamento de Química, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS (Brazil); Flores, Eder L.M. [Núcleo de Química, Universidade Tecnológica Federal do Paraná, 85884-000 Medianeira, PR (Brazil); Mesko, Marcia F. [Centro de Ciências Químicas, Farmacêuticas e de Alimentos, Universidade Federal de Pelotas, 96010-610 Pelotas, RS (Brazil); Flores, Erico M.M. [Departamento de Química, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS (Brazil); Mello, Paola A., E-mail: paola.mello@ufsm.br [Departamento de Química, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS (Brazil)

    2015-05-01

    In this work, bromine and iodine determination in milk powder for adult and infant nutrition was performed by inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP-OES) after digestion by microwave-induced combustion (MIC). Contrarily to previous works using MIC, a higher sample mass was digested (700 mg). Water and ammonium hydroxide (10 to 100 mmol L{sup −1}) were investigated as absorbing solutions and accurate results were achieved using a 25 mmol L{sup −1} NH{sub 4}OH solution. Moreover, the high stability of analytes after digestion (up to 30 days) using this solution was observed. The accuracy of the proposed MIC method was evaluated using certified and reference materials of milk powder (NIST 1549 and NIST 8435). No statistical difference was observed between results obtained by MIC-ICP-MS and reference values. Results for samples were also compared with those obtained by ICP-OES and no statistical difference was observed. Microwave-assisted alkaline extraction (MW-AE) was also evaluated for milk powder using NH{sub 4}OH and tetramethylammonium hydroxide solutions. Solutions obtained after digestion by MIC (whole milk powder) presented low carbon content in digests (< 25 mg L{sup −1}) while solutions obtained after alkaline extraction presented up to 10,000 mg L{sup −1} of C. MIC method was preferable in view of the possibility of obtaining solutions with low carbon content even using a relatively high sample mass (up to 700 mg) avoiding additional dilution prior to ICP-MS analysis, thus allowing better detection limits. Limits of detection obtained by MIC-ICP-MS were 0.007 and 0.003 μg g{sup −1} for Br and I, respectively, while for MW-AE were 0.1 and 0.05 μg g{sup −1} respectively for Br and I. Among the main advantages of the proposed method are the use of diluted alkaline solutions that is in agreement with green analytical chemistry recommendations, the high stability of

  18. An Assessment of a Rapid Microwave Thawing Procedure for Frozen Red Blood Cells.

    Science.gov (United States)

    1992-08-01

    Restall CJ, Leonard PF, Taswell HF, Holaday RE. A microwave blood warmer: preliminary report. Anesthesia and Analgesia 4,5(5):625-628, 1967. 9. duPlessis...Leonard PF, Restall CJ, Taswell HF, Fairbanks VF. Microwave warming of bank blood. Anesthesia and Analgesia 50(2):302-305, 1971’ 12. Stapies PJ

  19. Simultaneous determination of bromine and iodine in milk powder for adult and infant nutrition by plasma based techniques after digestion using microwave-induced combustion

    Science.gov (United States)

    Picoloto, Rochele S.; Doneda, Morgana; Flores, Eder L. M.; Mesko, Marcia F.; Flores, Erico M. M.; Mello, Paola A.

    2015-05-01

    In this work, bromine and iodine determination in milk powder for adult and infant nutrition was performed by inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP-OES) after digestion by microwave-induced combustion (MIC). Contrarily to previous works using MIC, a higher sample mass was digested (700 mg). Water and ammonium hydroxide (10 to 100 mmol L- 1) were investigated as absorbing solutions and accurate results were achieved using a 25 mmol L- 1 NH4OH solution. Moreover, the high stability of analytes after digestion (up to 30 days) using this solution was observed. The accuracy of the proposed MIC method was evaluated using certified and reference materials of milk powder (NIST 1549 and NIST 8435). No statistical difference was observed between results obtained by MIC-ICP-MS and reference values. Results for samples were also compared with those obtained by ICP-OES and no statistical difference was observed. Microwave-assisted alkaline extraction (MW-AE) was also evaluated for milk powder using NH4OH and tetramethylammonium hydroxide solutions. Solutions obtained after digestion by MIC (whole milk powder) presented low carbon content in digests (< 25 mg L- 1) while solutions obtained after alkaline extraction presented up to 10,000 mg L- 1 of C. MIC method was preferable in view of the possibility of obtaining solutions with low carbon content even using a relatively high sample mass (up to 700 mg) avoiding additional dilution prior to ICP-MS analysis, thus allowing better detection limits. Limits of detection obtained by MIC-ICP-MS were 0.007 and 0.003 μg g- 1 for Br and I, respectively, while for MW-AE were 0.1 and 0.05 μg g- 1 respectively for Br and I. Among the main advantages of the proposed method are the use of diluted alkaline solutions that is in agreement with green analytical chemistry recommendations, the high stability of analytes in solution and the suitability of digests for

  20. Microwave irradiation induced changes in protein molecular structures of barley grains: relationship to changes in protein chemical profile, protein subfractions, and digestion in dairy cows.

    Science.gov (United States)

    Yan, Xiaogang; Khan, Nazir A; Zhang, Fangyu; Yang, Ling; Yu, Peiqiang

    2014-07-16

    The objectives of this study were to evaluate microwave irradiation (MIR) induced changes in crude protein (CP) subfraction profiles, ruminal CP degradation characteristics and intestinal digestibility of rumen undegraded protein (RUP), and protein molecular structures in barley (Hordeum vulgare) grains. Samples from hulled (n = 1) and hulless cultivars (n = 2) of barley, harvested from four replicate plots in two consecutive years, were evaluated. The samples were either kept as raw or irradiated in a microwave for 3 min (MIR3) or 5 min (MIR5). Compared to raw grains, MIR5 decreased the contents of rapidly degradable CP subfraction (from 45.22 to 6.36% CP) and the ruminal degradation rate (from 8.16 to 3.53%/h) of potentially degradable subfraction. As a consequence, the effective ruminal degradability of CP decreased (from 55.70 to 34.08% CP) and RUP supply (from 43.31 to 65.92% CP) to the postruminal tract increased. The MIR decreased the spectral intensities of amide 1, amide II, α-helix, and β-sheet and increased their ratios. The changes in protein spectral intensities were strongly correlated with the changes in CP subfractions and digestive kinetics. These results show that MIR for a short period (5 min) with a lower energy input can improve the nutritive value and utilization of CP in barely grains.

  1. Assessment of Aspartame Exposure Due to Consumption of Some Imported Chewing Gums by Microwave Digestion and High Performance Liquid Chromatography Analysis

    Directory of Open Access Journals (Sweden)

    Zohreh Rasouli

    2016-06-01

    Full Text Available Aspartame is a widely used artificial sweetener, the long-term safety of which has been controversial ever since it was accepted for human consumption. The main aim of this research is assessment of aspartame exposure due to consumption of some imported chewing gums during summer 2015 to Iran by microwave digestion and HPLC analysis. Thirty chewing gums from highly consumed imported ones were collected from retail market in Tehran. Closed vessel microwave digestion was employed for sample preparation using a three phase temperature program. An aliquot of 20 μL of prepared samples was injected into the HPLC column and the aspartame was detected at 254 nm with an on-line detector. Concentration of aspartame in chewing gum samples was between 1.9 and 30.5 μg/g with an average of 11.1 μg/g. In conclusion, despite of existing aspartame in 76.6 percent of samples, however the effective amount of this artificial sweetener is not as high as the levels that international legislations recommended for exposing due to chewing gum consumption.

  2. Accurate determination of sulfur in gasoline and related fuel samples using isotope dilution ICP-MS with direct sample injection and microwave-assisted digestion.

    Science.gov (United States)

    Heilmann, Jens; Boulyga, Sergei F; Heumann, Klaus G

    2004-09-01

    Inductively coupled plasma isotope-dilution mass spectrometry (ICP-IDMS) with direct injection of isotope-diluted samples into the plasma, using a direct injection high-efficiency nebulizer (DIHEN), was applied for accurate sulfur determinations in sulfur-free premium gasoline, gas oil, diesel fuel, and heating oil. For direct injection a micro-emulsion consisting of the corresponding organic sample and an aqueous 34S-enriched spike solution with additions of tetrahydronaphthalene and Triton X-100, was prepared. The ICP-MS parameters were optimized with respect to high sulfur ion intensities, low mass-bias values, and high precision of 32S/34S ratio measurements. For validation of the DIHEN-ICP-IDMS method two certified gas oil reference materials (BCR 107 and BCR 672) were analyzed. For comparison a wet-chemical ICP-IDMS method was applied with microwave-assisted digestion using decomposition of samples in a closed quartz vessel inserted into a normal microwave system. The results from both ICP-IDMS methods agree well with the certified values of the reference materials and also with each other for analyses of other samples. However, the standard deviation of DIHEN-ICP-IDMS was about a factor of two higher (5-6% RSD at concentration levels above 100 mircog g(-1)) compared with those of wet-chemical ICP-IDMS, mainly due to inhomogeneities of the micro-emulsion, which causes additional plasma instabilities. Detection limits of 4 and 18 microg g(-1) were obtained for ICP-IDMS in connection with microwave-assisted digestion and DIHEN-ICP-IDMS, respectively, with a sulfur background of the used Milli-Q water as the main limiting factor for both methods.

  3. Accurate determination of sulfur in gasoline and related fuel samples using isotope dilution ICP-MS with direct sample injection and microwave-assisted digestion

    Energy Technology Data Exchange (ETDEWEB)

    Heilmann, Jens; Boulyga, Sergei F.; Heumann, Klaus G. [Johannes Gutenberg-University, Institute of Inorganic Chemistry and Analytical Chemistry, Mainz (Germany)

    2004-09-01

    Inductively coupled plasma isotope-dilution mass spectrometry (ICP-IDMS) with direct injection of isotope-diluted samples into the plasma, using a direct injection high-efficiency nebulizer (DIHEN), was applied for accurate sulfur determinations in sulfur-free premium gasoline, gas oil, diesel fuel, and heating oil. For direct injection a micro-emulsion consisting of the corresponding organic sample and an aqueous {sup 34}S-enriched spike solution with additions of tetrahydronaphthalene and Triton X-100, was prepared. The ICP-MS parameters were optimized with respect to high sulfur ion intensities, low mass-bias values, and high precision of {sup 32}S/{sup 34}S ratio measurements. For validation of the DIHEN-ICP-IDMS method two certified gas oil reference materials (BCR 107 and BCR 672) were analyzed. For comparison a wet-chemical ICP-IDMS method was applied with microwave-assisted digestion using decomposition of samples in a closed quartz vessel inserted into a normal microwave system. The results from both ICP-IDMS methods agree well with the certified values of the reference materials and also with each other for analyses of other samples. However, the standard deviation of DIHEN-ICP-IDMS was about a factor of two higher (5-6% RSD at concentration levels above 100 {mu}g g{sup -1}) compared with those of wet-chemical ICP-IDMS, mainly due to inhomogeneities of the micro-emulsion, which causes additional plasma instabilities. Detection limits of 4 and 18 {mu}g g{sup -1} were obtained for ICP-IDMS in connection with microwave-assisted digestion and DIHEN-ICP-IDMS, respectively, with a sulfur background of the used Milli-Q water as the main limiting factor for both methods. (orig.)

  4. 微波消解-GFAAS法测定土壤中的总铅%Determination of Total Lead Contents in Soil by Microwave Digestion-GFAAS

    Institute of Scientific and Technical Information of China (English)

    马小宁; 姬勇

    2013-01-01

    研究了微波消解-GFAAS法测定土壤样品中总铅的方法.土壤样品加入HNO3+HF,经微波消解体系消解后,在恒温加热器上赶酸并除硅,石墨炉原子吸收光谱法(GFAAS)测定土壤样品中的总铅.测定数据经过与国标(GB/T 17141-1997)消解方法的比对,以及对不同土壤及土壤标准物质的测试.结果表明,两者无显著性差异,且此法重复性好,试剂用量少,安全易控制,结果可靠.%It studied a method of microwave digestion-GFAAS for the determination of total lead in soil. HNO3 and HF were added into the soil samples,the microwave digestion under the certain condition was conducted and in a constant temperature heater to drive acid and remove silicon, then total lead content in soil was determined by Graphite Furnace Atomic Absorption Spectrometric(GFAAS) method. Compared with the national standard (GB/T 17141-1997) digestion method ,and determined the different soil and soil standard substances, the results show that: the two methods have no significant difference. This method is well repeatable, with less reagent dosage, safe and easy to control and it is reliable.

  5. The direct determination of the forms of sulphur in coal using microwave digestion and i.c.p.-a.e.s. analysis

    Energy Technology Data Exchange (ETDEWEB)

    Laban, K.L.; Atkin, B.P. [University of Nottingham, Nottingham (United Kingdom). School of Chemical, Environmental and Mining Engineering

    2000-01-01

    A sequential digestion method is reported for the direct determination of sulphate, pyrite and organic sulphur concentrations in coals of either bituminous or sub-bituminous rank. A three stage extraction was developed, using acid digestion in a microwave oven. In the first stage, 5 M HCl is used to dissolve sulphate phases in the coal. Pyrite is then extracted from the stage 1 residue using 2 M HNO{sub 3}. The final stage, for the determination of organic sulphur, involves the use of concentrated HNO{sub 3}, HCl, HF and boric acid for the complete decomposition of residue that remains following stage 2. The extract solutions from each stage are rapidly analysed for sulphur using i.c.p.-a.e.s. The sums of the three forms of sulphur have shown consistent agreement with certified total sulphur data for most of the coals studied. This correlation, in addition to the good precision achieved by this technique, suggests that the sequential digestion method is reliable. Furthermore, significant timesavings are achievable over some of the standard techniques demonstrating the suitability of the method for routine analyses. 12 refs., 1 fig., 8 tabs.

  6. Determination of total lead in lipstick: development and validation of a microwave-assisted digestion, inductively coupled plasma-mass spectrometric method.

    Science.gov (United States)

    Hepp, Nancy M; Mindak, William R; Cheng, John

    2009-01-01

    Recent reports describing the presence of lead (Pb) in lipsticks have suggested that, under ordinary use, the potential amount of Pb exposure is harmful. To permit independent assessment of the Pb contamination, a method for determining total Pb in lipstick using microwave-assisted digestion and analysis employing inductively coupled plasma-mass spectrometry (ICP-MS) was developed and validated. Since lipsticks may contain fats, oils, pigments, dyes, and minerals, several reference materials (RM) were analyzed, including coal, wear metals in oil, organic Pb in oil, milk powder, and estuarine sediment. With the exception of the RM with mineral content (estuarine sediment), complete recovery of Pb from the RMs was obtained by simple nitric acid (HNO(3)) digestion. Complete recovery of Pb from estuarine sediment was achieved only when hydrofluoric acid (HF) was added to the digestion mix, followed by treatment with excess boric acid (H(3)BO(3)) to neutralize the HF and to dissolve insoluble fluorides. Commercial lipsticks were tested for total Pb by the validated method. The detection limit was estimated to be 0.04 microg Pb/g. The average value obtained for the lipsticks was 1.07 microg/g. Undigested material was present in some lipstick digests when only HNO(3) was used, and generally lower Pb values were obtained. All of the Pb levels found by the U.S. Food and Drug Administration (FDA) were within the range the agency would expect to find in lipsticks formulated with permitted color additives and other ingredients prepared under good manufacturing practice (GMP) conditions. This method will be useful for the FDA and industry in helping to ensure the safety of cosmetic products.

  7. Investigation on cleaning methods for chromium residue in microwave digestion tanks%微波消解罐铬残留清洗方法的探讨

    Institute of Scientific and Technical Information of China (English)

    张秉华; 吕卓; 马元斌; 邓颖鹏; 王嫦鹤; 刘海静

    2012-01-01

    Objective:To determine the best cleaning method for microwave digestion tanks. Methods; Five cleaning methods were selected to clean the digestion tank that had been used for different samples (with the chromium concentration of 0. 7,2. 7,4 and 40 mg · kg‐1 ). Trace chromium in the digestion tanks was analyzed by microwave digestion and graphite furnace atomic absorption spectrometry. Results; The chromium residue in the digested tanks can be cleaned by two cleaning methods as "soak for 1 h with hydrochloric acid solution(1→2) ,soak for 1 h with nitric acid solution(1→2) ,then wash three times with deionized water" and "soak for 8 -12 h with nitric acid solution (1 →5), wash three times with deionized water". Conclusion; The cleaning methods of " soak for 1 h with hydrochloric acid solution(1→2) ,soak for 1 h with nitric acid solution(1→2) ,then wash three times with deionized water" not only can save time but also ensure the accuracy of the post - experimental results, which can be used for microwave digestion tanks cleaning during chromium determination process.%目的:确定微波消解罐的最佳清洗方法.方法:分别选用5种清洗方法对消解了不同样品(铬浓度分别为0.7,2.7,4,40 mg·kg-1)的消解罐进行清洗,采用微波消解以原子吸收分光光度计对清洗后消解罐中残留铬的含量进行测定.结果:“盐酸溶液(1→2)浸泡1h,再用硝酸浸泡1h,去离子水清洗3遍”或“用硝酸溶液(1→5)浸泡8~12h,用去离子水清洗3遍”都可以将消解罐中残留的铬清洗干净.结论:“盐酸溶液(1→2)浸泡1h,再用硝酸溶液(1→2)浸泡Ih,去离子水清洗3遍”的清洗方法,既可以节约时间,又可以保证后期实验结果的准确性,可用于铬测定过程中微波消解罐的清洗.

  8. Improvement of microwave-assisted digestion of milk powder with diluted nitric acid using oxygen as auxiliary reagent

    Energy Technology Data Exchange (ETDEWEB)

    Bizzi, Cezar A. [Departamento de Quimica, Universidade Federal de Santa Maria, 97105-900, Santa Maria, RS (Brazil); Instituto Nacional de Ciencia e Tecnologia de Bioanalitica, Campinas, SP (Brazil); Barin, Juliano S. [Departamento de Tecnologia e Ciencia dos Alimentos, Universidade Federal de Santa Maria, 97105-900, Santa Maria, RS (Brazil); Garcia, Edivaldo E. [Departamento de Quimica, Universidade Estadual de Maringa, 87100-900, Maringa, PR (Brazil); Nobrega, Joaquim A. [Departamento de Quimica, Universidade Federal de Sao Carlos, 13565-905, Sao Carlos, SP (Brazil); Dressler, Valderi L. [Departamento de Quimica, Universidade Federal de Santa Maria, 97105-900, Santa Maria, RS (Brazil); Instituto Nacional de Ciencia e Tecnologia de Bioanalitica, Campinas, SP (Brazil); Flores, Erico M.M., E-mail: ericommf@gmail.com [Departamento de Quimica, Universidade Federal de Santa Maria, 97105-900, Santa Maria, RS (Brazil); Instituto Nacional de Ciencia e Tecnologia de Bioanalitica, Campinas, SP (Brazil)

    2011-05-15

    The feasibility of using diluted HNO{sub 3} solutions under oxygen pressure for decomposition of whole and non-fat milk powders and whey powder samples has been evaluated. Digestion efficiency was evaluated by determining the carbon content in solution (digests) and the determination of Ca, Cd, Cu, Fe, K, Mg, Mn, Mo, Na, Pb and Zn was performed by inductively coupled plasma optical emission spectrometry and Hg by chemical vapor generation coupled to inductively coupled plasma mass spectrometry. Samples (up to 500 mg) were digested using HNO{sub 3} solutions (1 to 14 mol L{sup -1}) and the effect of oxygen pressure was evaluated between 2.5 and 20 bar. It was possible to perform the digestion of 500 mg of milk powder using 2 mol L{sup -1} HNO{sub 3} with oxygen pressure ranging from 7.5 to 20 bar with resultant carbon content in digests lower than 1700 mg L{sup -1}. Using optimized conditions, less than 0.86 mL of concentrated nitric acid (14 mol L{sup -1}) was enough to digest 500 mg of sample. The accuracy was evaluated by determination of metal concentrations in certified reference materials, which presented an agreement better than 95% (Student's t test, P < 0.05) for all the analytes.

  9. 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).

    Science.gov (United States)

    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.

  10. Evaluation of cadmium in greenhouse soils and agricultural products of Jiroft (Iran) using microwave digestion prior to atomic absorption spectrometry determination.

    Science.gov (United States)

    Afzali, Daryoush; Fathirad, Fariba; Afzali, Zahra; Majdzadeh-Kermani, Seyed Mohammad Javad

    2015-03-01

    This study determines total levels of potentially toxic trace element, Cd (II) in Jiroft (Kerman, Iran) greenhouse soil and agricultural products that are grown in these greenhouses (tomatoes and cucumbers), and the comparison with soil outside of greenhouse using microwave digestion prior to flame atomic absorption spectrometry determination. The results show that the cadmium concentration in greenhouse soil is 0.9-1.9 mg kg(-1) and out of greenhouse is 0.4-1.0 mg kg(-1). Also, cadmium concentration range in tomatoes and cucumbers is about 0.07-0.40 mg kg(-1). The obtained results show that the concentration of this metal in greenhouse soil is higher than outside soil samples and is below the safe limit.

  11. Calibration and Verification Procedures at ARL for the Focus Microwaves Load Pull System

    Science.gov (United States)

    2006-11-01

    greater understanding of S-parameters, refer to the text by Pozar (1). In order to determine the performance of a device, it is necessary to have a...serve as a basic primer for this knowledge as it applies to our high frequency test configuration. 13 References 1. Pozar , D. M., Microwave

  12. 76 FR 12825 - Energy Conservation Program for Consumer Products: Test Procedure for Microwave Ovens

    Science.gov (United States)

    2011-03-09

    .... Department of Energy, Building Technologies Program, 6th Floor, 950 L'Enfant Plaza, SW., Washington, DC 20024... with or without thermal elements designed for surface browning of food and combination ovens. DOE..., including microwave ovens with or without thermal elements designed for surface browning of food. DOE...

  13. 78 FR 7939 - Energy Conservation Program: Test Procedures for Microwave Ovens (Active Mode)

    Science.gov (United States)

    2013-02-04

    ... Committee for Electrotechnical Standardization (CENELEC) conducted a round-robin testing program to evaluate...-robin test program. (AHAM, No. 18 at pp. 2-3; \\8\\ Whirlpool, No. 15 at p. 1) AHAM and Whirlpool..., whereas a hood fan used for cooling an over-the-range microwave oven is typically rated at 100-200 watts...

  14. Determination of mercury in hair by square-wave anodic stripping voltammetry at a rotating gold disk electrode after microwave digestion.

    Science.gov (United States)

    East, Gaston A; Marinho, Epitácio P

    2005-03-01

    A simple and reliable method for the determination of mercury in hair on a rotating gold disk electrode using subtractive anodic stripping voltammetry without removal of oxygen is reported. Voltammetric and microwave parameters were optimized to obtain the best analytical results. Parameters such as supporting electrolyte concentration, influence of chloride in the Hg peak, deposition potential, scan rate, accumulation time, rotation rate, square-wave amplitude, and electrode conditioning were studied. Pressurized microwave-assisted digestion of hair, suitable for the accurate voltammetric determination of Hg, was evaluated using six acid mixtures and several time-power programs. Under the optimized conditions, no interference by copper, cadmium, lead, nickel, manganese, iron, or zinc was found at concentrations corresponding to their occurrence in normal hair. A calibration plot between 6,67 and 46,69 microg/L was linear, with r(2) better than 0.999. The detection limit for a deposition time of 60 s at 254 g was calculated as 1.92 nM (3omega). Validation of the method was demonstrated with the use of a certified reference sample of hair. Eight real samples of hair (four unexposed children and four exposed persons) were also analyzed.

  15. Effect of HF addition on the microwave-assisted acid-digestion for the determination of metals in coal by inductively coupled plasma-atomic emission spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yan-Hua [Department of Environmental Science and Engineering, College of Urban Construction and Safety and Environmental Engineering, Nanjing University of Technology, No. 200 Zhongshan Beilu, Nanjing 210009, Jiangsu (China); Iwashita, A.; Nakajima, T.; Yamashita, H.; Takanashi, H.; Ohki, A. [Department of Bioengineering, Faculty of Engineering, Kagoshima University, 1-21-40, Korimoto, Kagoshima 890-0065 (Japan)

    2005-03-31

    The microwave-assisted acid-digestion for the determination of metals in coal by ICP-AES was investigated, especially focusing on the necessity of adding HF. By testing five certified reference materials, BCR-180, BCR-040, NIST-1632b, NIST-1632c, and SARM-20, it was found that the two-stage digestion without HF (HNO{sub 3}+H{sub 2}O{sub 2} was used) was very effective for the pretreatment of ICP-AES measurement. Both major metals (Al, Ca, Fe, and Mg) and minor or trace metals (Co, Cr, Cu, Mn, Ni, Pb, and Zn) in coal gave good recoveries for their certified or reference values. The possibility of 'HF-memory effect' was cancelled by the use of a set of vessels which had been never contacted with HF. Twenty-four Japanese standard coals (SS coals) were analyzed by the present method, and the concentrations of major metals measured by the present method provided very high accordance with those from the authentic JIS (Japanese Industrial Standard) method.

  16. Effect of HF addition on the microwave-assisted acid-digestion for the determination of metals in coal by inductively coupled plasma-atomic emission spectrometry.

    Science.gov (United States)

    Xu, Yan-Hua; Iwashita, Akira; Nakajima, Tsunenori; Yamashita, Hiroyuki; Takanashi, Hirokazu; Ohki, Akira

    2005-03-31

    The microwave-assisted acid-digestion for the determination of metals in coal by ICP-AES was investigated, especially focusing on the necessity of adding HF. By testing five certified reference materials, BCR-180, BCR-040, NIST-1632b, NIST-1632c, and SARM-20, it was found that the two-stage digestion without HF (HNO(3)+H(2)O(2) was used) was very effective for the pretreatment of ICP-AES measurement. Both major metals (Al, Ca, Fe, and Mg) and minor or trace metals (Co, Cr, Cu, Mn, Ni, Pb, and Zn) in coal gave good recoveries for their certified or reference values. The possibility of 'HF-memory effect' was cancelled by the use of a set of vessels which had been never contacted with HF. Twenty-four Japanese standard coals (SS coals) were analyzed by the present method, and the concentrations of major metals measured by the present method provided very high accordance with those from the authentic JIS (Japanese Industrial Standard) method.

  17. Determination of arsenic, cadmium, cobalt, chromium, lead, molybdenum, nickel, and selenium in fertilizers by microwave digestion and inductively coupled plasma-optical emission spectrometry detection: collaborative study.

    Science.gov (United States)

    Kane, Peter F; Hall, William L

    2006-01-01

    There is increasing regulatory interest in the non-nutritive metals content of fertilizer materials, but at present there is no consensus analytical method for acid digestion and instrument detection of those elements in fertilizer matrixes. This lack of method standardization has resulted in unacceptable variability of results between fertilizer laboratories performing metals analysis. A method has been developed using microwave digestion with nitric acid at 200 degrees C, followed by inductively coupled plasma-optical emission spectrometry instrument detection, for the elements arsenic, cadmium, cobalt, chromium, molybdenum, nickel, lead, and selenium. The method has been collaboratively studied, and statistical results are here reported. Fourteen collaborators were sent 62 sample materials in a blind duplicate design. Materials represented a broad cross section of fertilizer types, including phosphate ore, manufactured phosphate products, N-P-K blends, organic fertilizers, and micro-nutrient materials. As much as possible within the limit of the number of samples, materials were selected from different regions of the United States and the world. Limit of detection (LOD) was determined using synthetic fertilizers consisting of reagent grade chemicals with near zero levels of the non-nutritive elements, analyzed blindly. Samples with high iron content caused the most variability between laboratories. Most samples reasonably above LOD gave HorRat values within the range 0.5 to 2.0, indicating acceptable method performance according to AOAC guidelines for analyses in the mg/kg range. The method is recommended for AOAC Official First Action status.

  18. Evaluation of bromine and iodine content of milk whey proteins combining digestion by microwave-induced combustion and ICP-MS determination.

    Science.gov (United States)

    da Silva, Sabrina Vieira; Picoloto, Rochele Sogari; Flores, Erico Marlon Moraes; Wagner, Roger; Dos Santos Richards, Neila Silvia Pereira; Barin, Juliano Smanioto

    2016-01-01

    The bromine and iodine content of whey protein concentrate (WPC), hydrolysate (WPH), and isolate (WPI) was evaluated combining microwave-induced combustion (MIC) digestion with inductively coupled plasma mass spectrometry (ICP-MS) determination. MIC digestion allowed the decomposition of up to 500 mg of samples using diluted NH4OH solution (25 mmol L(-1)) for absorption of analytes, assuring the compatibility with ICP-MS determination. Accuracy was evaluated using milk powder certified reference material (NIST 8435) with good agreements for Br and I (102% and 105%, respectively). For Br and I, the limit of quantification obtained by ICP-MS was 7 and 281 times lower in comparison with ion chromatography determination, respectively. Iodine could be enriched in whey protein production and up to 70% of the tolerable upper intake level was found, thus revealing the need to monitor it in whey proteins. On the other hand, the concentration of Br was below its acceptable daily intake. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Assessment of microbial viability in municipal sludge following ultrasound and microwave pretreatments and resulting impacts on the efficiency of anaerobic sludge digestion.

    Science.gov (United States)

    Cella, Monica Angela; Akgul, Deniz; Eskicioglu, Cigdem

    2016-03-01

    A range of ultrasonication (US) and microwave irradiation (MW) sludge pretreatments were compared to determine the extent of cellular destruction in micro-organisms within secondary sludge and how this cellular destruction translated to anaerobic digestion (AD). Cellular lysis/inactivation was measured using two microbial viability assays, (1) Syto 16® Green and Sytox® Orange counter-assay to discern the integrity of cellular membranes and (2) a fluorescein diacetate assay to understand relative enzymatic activity. A range of MW intensities (2.17-6.48 kJ/g total solids or TS, coinciding temperatures of 60-160 °C) were selected for comparison via viability assays; a range of corresponding US intensities (2.37-27.71 kJ/g TS, coinciding sonication times of 10-60 min at different amplitudes) were also compared to this MW range. The MW pretreatment of thickened waste activated sludge (tWAS) caused fourfold to fivefold greater cell death than non-pretreated and US-pretreated tWAS. The greatest microbial destruction occurred at MW intensities greater than 2.62 kJ/g TS of sludge, after which increased energy input via MW did not appear to cause greater microbial death. In addition, the optimal MW pretreatment (80 °C, 2.62 kJ/g TS) and corresponding US pretreatment (10 min, 60 % amplitude, 2.37 kJ/g TS) were administered to the tWAS of a mixed sludge and fed to anaerobic digesters over sludge retention times (SRTs) of 20, 14, and 7 days to compare effects of feed pretreatment on AD efficiency. The digester utilizing MW-pretreated tWAS (80 °C, 2.62 kJ/g TS) had the greatest fecal coliform removal (73.4 and 69.8 % reduction, respectively), greatest solids removal (44.2 % TS reduction), and highest overall methane production (248.2 L CH4/kg volatile solids) at 14- and 7-day SRTs. However, despite the fourfold to fivefold increases in cell death upon pretreatment, improvements from the digester fed MW-pretreated sludge were marginal (i.e., increases in efficiency of less

  20. Effect of microwave pre-treatment of thickened waste activated sludge on biogas production from co-digestion of organic fraction of municipal solid waste, thickened waste activated sludge and municipal sludge.

    Science.gov (United States)

    Ara, E; Sartaj, M; Kennedy, K

    2014-12-01

    Anaerobic co-digestion of organic fraction of municipal solid waste, with thickened waste activated sludge and primary sludge has the potential to enhance biodegradation of solid waste, increase longevity of existing landfills and lead to more sustainable development by improving waste to energy production. This study reports on mesophilic batch and continuous studies using different concentrations and combinations (ratios) of organic fraction of municipal solid waste, thickened waste activated sludge (microwave pre-treated and untreated) and primary sludge to assess the potential for improved biodegradability and specific biogas production. Improvements in specific biogas production for batch assays, with concomitant improvements in total chemical oxygen demand and volatile solid removal, were obtained with organic fraction of municipal solid waste:thickened waste activated sludge:primary sludge mixtures at a ratio of 50:25:25 (with and without thickened waste activated sludge microwave pre-treatment). This combination was used for continuous digester studies. At 15 d hydraulic retention times, the co-digestion of organic fraction of municipal solid waste:organic fraction of municipal solid waste:primary sludge and organic fraction of municipal solid waste:thickened waste activated sludge microwave:primary sludge resulted in a 1.38- and 1.46-fold increase in biogas production and concomitant waste stabilisation when compared with thickened waste activated sludge:primary sludge (50:50) and thickened waste activated sludge microwave:primary sludge (50:50) digestion at the same hydraulic retention times and volumetric volatile solid loading rate, respectively. The digestion of organic fraction of municipal solid waste with primary sludge and thickened waste activated sludge provides beneficial effects that could be implemented at municipal wastewater treatment plants that are operating at loading rates of less than design capacity.

  1. 微波消解石墨炉原子吸收光谱法测定茶叶中镍%Determination of Nickel in Tea by Graphite Furnace Atomic Absorption Spectrometry with Microwave Digestion

    Institute of Scientific and Technical Information of China (English)

    郑国庚; 李美

    2011-01-01

    [目的]利用微波消解石墨炉原子吸收法测定茶叶中镍含量.[方法]分别从消解液和样品消解量方面进行消解条件的优化,以建立最适合的消解方法.[结果]茶叶样品以5 ml HNO3-2 ml H2O2 混合体系为消解液,坡度升温方式微波高压密闭消解结合石墨炉原子吸收光谱法测定,样品检出限为0.15 μg/g,回收率为97.8%,RSD为1.9%.[结论]该方法简单快速,效率高,劳动强度低,是进行茶叶中镍元素测定的高效方法.%[ Objective ] The study aimed to determine the nickel in tea by using the graphite furnace atomic absorption spectrometry (GFAAS) with microwave digestion. [ Method ] The digestion conditions were optimized separately from the digestion fluid and sample digestion quantity to establish the most appropriate digestion method. [ Result] When 5 ml HNO3 -2 ml H2O2 mixed system was taken as the digestion liquid for digesting the tea samples and the GFAAS combined with the microwave high-pressure airtight digestion under slope heating was used to determine the nickel in the tea samples, the sample detecting limit was 0. 15 μg/g, the recovery was 97.8% and the precise RSD was 1.9%.[ Conclusion ] This method was simple and rapid and had high efficiency and low labor strength, which was a efficient method for detemining nickel element in the tea.

  2. Determination of metal traces in lubricating oils by Aas and Icp-SFMS after microwave digestion; Determinacion de trazas metalicas en aceites lubricantes mediante EAA e ICP-SFMS despues de la digestion por microondas

    Energy Technology Data Exchange (ETDEWEB)

    Perez B, M. A.; Acosta L, C. E.; Hernandez M, H.; Romero G, E. T.; Lara A, N.; Kuri C, A., E-mail: manuel.perez@inin.gob.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2016-09-15

    The analysis of lubricating oils allows to monitor the operating conditions of the machines and equipment, their pollution levels, degradation and finally their wear and useful life, as well as to establish a preventive lubrication program as a technical diagnostic maintenance tool. The useful life of oil is the period of functional time has in the machine until the antioxidants are consumed, producing large changes in the physical (density and viscosity) and chemical properties of the base oil, resulting in a wear of the components that make up the machine. The present work includes a theoretical as well as analytical basis for determining the content of metallic elements (Ag, Al, Cu, Fe, Mg, Sn and Zn) at trace level in used lubricating oils. A simple and rapid method of analysis is proposed, consisting mainly of the pretreatment of the sample by acidic digestion with a microwave oven. Subsequently an open digestion in a heating plate is carried out to dryness and recovered with concentrated HNO{sub 3}. For the quantitative analysis two analytical techniques were used: flame atomic absorption spectroscopy (Aas) and magnetic sector mass spectrometry with inductively coupled plasma source (Icp-SFMS). In both cases, the proposed method offers a good linearity and sensitivity for each of the trace elements under study. The accuracy of the method expressed as relative standard deviation ranges from 1.4 to 2.3%. In relation to the accuracy measurement, an oil was also analyzed as a certified reference material (Conostan 500 mg/L), with the concentration of certified Mg, obtaining satisfactory results. (Author)

  3. Novel procedure for estimating endogenous losses and measurement of apparent and true digestibility of phosphorus by growing pigs.

    Science.gov (United States)

    Petersen, G I; Stein, H H

    2006-08-01

    An experiment was conducted to evaluate a novel procedure for estimating endogenous losses of P and for measuring the apparent total tract digestibility (ATTD) and true total tract digestibility (TTTD) of P in 5 inorganic P sources fed to growing pigs. The P sources were dicalcium phosphate (DCP), monocalcium phosphate (MCP) with 50% purity (MCP50), MCP with 70% purity (MCP70), MCP with 100% purity (MCP100), and monosodium phosphate (MSP). A gelatin-based, P-free basal diet was formulated and used to estimate endogenous losses of P. Five P-containing diets were formulated by adding 0.20% total P from each of the inorganic P sources to the basal diet. A seventh diet was formulated by adding 0.16% P from MCP70 to the basal diet. All diets were fed to 7 growing pigs in a 7 x 7 Latin square design, and urine and feces were collected during 5 d of each period. The endogenous loss of P was estimated as 139 +/- 18 mg/kg of DMI. The ATTD of P in MSP was greater (P DCP, MCP50, and MCP70 (91.9 vs. 81.5, 82.6, and 81.7%, respectively). In MSP, the TTTD of P was 98.2%. This value was greater (P DCP, MCP50, and MCP70 (88.4, 89.5, and 88.6%, respectively). The ATTD and the TTTD for MCP70 were similar in diets formulated to contain 0.16 and 0.20% total P. Results from the current experiment demonstrate that a P-free diet may be used to measure endogenous losses of P in pigs. By adding inorganic P sources to this diet, the ATTD of P can be directly measured and the TTTD of P may be calculated for each source of P.

  4. Synthesis of quinoxaline 1,4-di-n-oxide derivatives on solid support using room temperature and microwave-assisted solvent-free procedures

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Caro, Lilia C.; Sanchez-Sanchez, Mario; Bocanegra-Garcia, Virgilio; Rivera, Gildardo [Universidad Autonoma de Tamaulipas, Reynosa (Mexico). Dept. de Farmacia y Quimica Medicinal; Monge, Antonio [Universidad de Navarra, Pamplona (Spain). Centro de Investigacion en Farmacobiologia Aplicada. Unidad de Investigacion y Desarrollo de Medicamentos

    2011-07-01

    We describe the synthesis of 12 new ethyl and methyl quinoxaline-7-carboxylate 1,4-di-N-oxide derivatives on solid supports with room temperature and microwave-assisted solvent-free procedures. Results show that solid supports have good catalytic activity in the formation of quinoxaline 1,4-di-N-oxide derivatives. We found that florisil and montmorillonite KSF and K10 could be used as new, easily available, inexpensive alternatives of catalysts. Additionally, room temperature and microwave-irradiation solvent-free synthesis was more efficient than a conventional procedure (Beirut reaction), reducing reaction time and increasing yield. (author)

  5. Phytochemical analysis of Myrtus communis plant: Conventional versus microwave assisted-extraction procedures.

    Science.gov (United States)

    Bouaoudia-Madi, Nadia; Boulekbache-Makhlouf, Lila; Kadri, Nabil; Dahmoune, Farid; Remini, Hocine; Dairi, Sofiane; Oukhmanou-Bensidhoum, Sonia; Madani, Khodir

    2017-06-10

    Background Myrtle (Myrtus communis L) may constitute an interesting dietary source of health protective compounds. Microwave-assisted extraction (MAE) of total phenolic compounds (TPC) from myrtle leaf, stems, pericarp, and seeds was studied and the results were compared with those of the conventional method extraction (CME) in terms of extraction time. Methods Extraction yield/efficiency and antioxidant activity were measured using radical scavenging assay (DPPH•) and reducing power. Results The results show that the MAE was higher in terms of saving energy, extraction time (62 s) and extraction efficiency of bioactive compound compared to CME (2 h). Leaf presented the optimum content of total phenols (250 mg GAE.g-1 DW) and flavonoids (13.65 mg GAE.g-1 DW). However, the anthocyanin content was most important in pericarp extract (176.50±2.17 mg Cyd-3-glu g-1 DW). The antioxidant activity was important in all parts, mainly in leaves. The results indicated that appropriate microwave treatment could be an efficient process to phenolic compounds recovery and thus, better the antioxidant activity of myrtle extract. Conclusions Principal component analysis (PCA) applied to the experimental data shows that the distribution of the myrtle phenolic compounds depended on their plant part localization as well as the extraction method.

  6. 微波预处理对秸秆厌氧消化影响的研究%Efficiency of anaerobic digestion of straw pretreated with microwave energy

    Institute of Scientific and Technical Information of China (English)

    冯磊; 李润东; Bernhard Raninger; Martin J.Gehring

    2009-01-01

    以秸秆为研究对象,比较不同的微波强度预处理作用下对秸秆厌氧消化产气特性的影响,研究日产气量、pH值、甲烷气体浓度及生物降解率4个参数的变化趋势,结果表明:微波预处理对秸秆厌氧消化有明显效果,平均日产气量由未被预处理的6.21 mL/g VS上升到8.16 mL/g VS,上升了31.33%,达到最大日产气量时间由原来的第12 d,提前至第2~第7 d不等,最大日产气量由原来的23.43 mL/g Vs上升到43.49 mL/g VS;在360~900 w范围内,微波强度越大,反应的pH值下降越快,秸秆厌氧消化最大日产气量越提前;经过微波预处理的甲烷浓度平均浓度由原来的50%提高至62%左右.其生物能范围也由未处理前的17.58 MJ/m3提高至23.46 MJ/m3,物降解率由未预处理的44.12%,提高至71.55%.%This paper briefly introduces the characteristics of the generation of high-energy biogas through anaerobic digestion of straw pretreated with microwave energy.Experiments were conducted on the change trend of daily gas production,pH value,concentration of methane in the gas and biodegradation.The main conclusions are as follows:there was an obvious effect of pretreatment with microwave energy on the efficiency of anaerobic di6.21 mL/g VS to 8.16 mL/g VS,respectively.The maximum daily gas production increased from 23.43 mL/g VS to 43.49 mL/g VS,respectively,and started after 12 and 2 to 7 d,respectively.The extent of the effects of pretreatment depended on the intensity of the microwave exposure.With exposure to microwave radiation increasing from 360 to 900 W,both the pH value of the digestion slurry and the time to maximum daily gas production decreased.Also,the CH4 concentration in the biogas increased from 50%to 62%,which was equivalent to an increase in bio-energy yield from 17.58 MJ/m3 to 23.46 MJ/m3.Furthermore.the extent of mineralization increased from 44.12%to 71.55%.

  7. The Determination of Nickel in Nickel-base Alloys Using Microwave Digestion-spectrophotometry%探究微波消解-光度法测定镍基合金中镍

    Institute of Scientific and Technical Information of China (English)

    郭魏

    2015-01-01

    对微波消解溶解高温合金试样和使用光度法测定高温合金中镍含量进行了探究。微波消解节省了传统常压下溶样时间;光度法测定镍基合金中镍,保证了结果的准确度和精密度,比传统重量法和滴定法更简便。%Microwave dissolving high temperature alloy specimens and spectrophotometric determination of nickel content in the high temperature alloy are explored. Microwave digestion saves digestion time under traditional pressure, spectrophotometric determination of nickel in nickel base alloy ensures accuracy and precision of the re-sults. It is more simple compared to the traditional weight method and titration method.

  8. The Gravimetric Analysis of Nickel Using a Microwave Oven

    Science.gov (United States)

    Carmosini, Nadia; Ghoreshy, Sanaz; Koether, Marina C.

    1997-08-01

    The procedure for the gravimetric quantitative analysis of the percent of nickel in steel has been modified to include the use of a microwave oven. Experiments performed with the microwave oven gave an average recovery of 99.9+0.3% whereas the conventional method gave a value of 99.5+0.6%. The Ni(DMG)2 samples, which were digested and dried in the microwave oven, showed no physical difference indicating that there was no chemical modification of the precipitate due to the microwave radiation. The microwave oven proved to be very useful for time efficiency, not only for the digestion and heating of the steel ore, but also for the drying of the ore, the crucibles, and the Ni(DMG)2 precipitate. The most significant advantages occur with the cooling time. However, it is not suggested that the entire experiment be performed with the microwave since constant attention, which is required with the microwave drying method, is not necessary for the conventional oven method. Therefore, in order to be more time effective, thought should be given as to which part of the method should be performed with the microwave and which should be performed with the conventional oven.

  9. 微波消解-ICP-AES法测底泥中的铜、镍等金属元素%Microwave digestion ICP-AES measure Copper, nickel and other metal elements in sediment

    Institute of Scientific and Technical Information of China (English)

    唐兴伟

    2013-01-01

    Microwave digestion ICP -AES measure Copper , nickel and other metal elements in sedimentdetermined through experiments and spiked recoveries recoveries between 88 to 102%.%采用微波消解-ICP-AES法测定底泥中的铜、镍等金属元素。通过实验和加标回收率的测定,回收率在88~102%之间。

  10. [A new concept in digestive surgery: the computer assisted surgical procedure, from virtual reality to telemanipulation].

    Science.gov (United States)

    Marescaux, J; Clément, J M; Nord, M; Russier, Y; Tassetti, V; Mutter, D; Cotin, S; Ayache, N

    1997-11-01

    Surgical simulation increasingly appears to be an essential aspect of tomorrow's surgery. The development of a hepatic surgery simulator is an advanced concept calling for a new writing system which will transform the medical world: virtual reality. Virtual reality extends the perception of our five senses by representing more than the real state of things by the means of computer sciences and robotics. It consists of three concepts: immersion, navigation and interaction. Three reasons have led us to develop this simulator: the first is to provide the surgeon with a comprehensive visualisation of the organ. The second reason is to allow for planning and surgical simulation that could be compared with the detailed flight-plan for a commercial jet pilot. The third lies in the fact that virtual reality is an integrated part of the concept of computer assisted surgical procedure. The project consists of a sophisticated simulator which has to include five requirements: visual fidelity, interactivity, physical properties, physiological properties, sensory input and output. In this report we will describe how to get a realistic 3D model of the liver from bi-dimensional 2D medical images for anatomical and surgical training. The introduction of a tumor and the consequent planning and virtual resection is also described, as are force feedback and real-time interaction.

  11. Determination of borax in yuba by inductively coupled plasma atomic emission spectrometry with microwave digestion%微波消解-等离子体发射光谱法测定腐竹中硼砂

    Institute of Scientific and Technical Information of China (English)

    黄子伟; 王世平; 汤大鹏

    2012-01-01

    The dielectric assisted microwave digestion conditions were selected by orthogonal design, the experimental design was used to investigate the effect of four parameters: microwave power, mixed acid ratio, mixed acid volume and digestion time. And the borax in Yuba was determination with Inductively Coupled Plasma Atomic Emission Spectrometry after microwave digestion. The detection limit of the method was 0.4 mg/kg, the recoveries were in the rang of 91.2%~103.9%, and relative standard deviations were less than 2%.%采用正交试验设计优化介质辅助微波消解样品的条件,以电感耦合等离子体发射光谱法(ICP-AES)测定腐竹中硼砂。考察了微波消解功率、混合酸的比例、混合酸用量、试样消解时间4个因素在不同水平条件下对仪器响应值的影响。在优化了微波消解条件下测定实际样品,方法检出限为0.4mg/kg,加标回收率为91.2%~103.9%,相对标准偏差〈2%。

  12. Development and Optimization of a Flocculation Procedure for Improved Solid-Liquid Separation of Digested Biomass

    Energy Technology Data Exchange (ETDEWEB)

    Patton, Caroline; Lischeske, James J.; Sievers, David A.

    2015-11-03

    One viable treatment method for conversion of lignocellulosic biomass to biofuels begins with saccharification (thermochemical pretreatment and enzymatic hydrolysis), followed by fermentation or catalytic upgrading to fuels such as ethanol, butanol, or other hydrocarbons. The post-hydrolysis slurry is typically 4-8 percent insoluble solids, predominantly consisting of lignin. Suspended solids are known to inhibit fermentation as well as poison catalysts and obstruct flow in catalyst beds. Thus a solid-liquid separation following enzymatic hydrolysis would be highly favorable for process economics, however the material is not easily separated by filtration or gravimetric methods. Use of a polyacrylamide flocculant to bind the suspended particles in a corn stover hydrolyzate slurry into larger flocs (1-2mm diameter) has been found to be extremely helpful in improving separation. Recent and ongoing research on novel pretreatment methods yields hydrolyzate material with diverse characteristics. Therefore, we need a thorough understanding of rapid and successful flocculation design in order to quickly achieve process design goals. In this study potential indicators of flocculation performance were investigated in order to develop a rapid analysis method for flocculation procedure in the context of a novel hydrolyzate material. Flocculation conditions were optimized on flocculant type and loading, pH, and mixing time. Filtration flux of the hydrolyzate slurry was improved 170-fold using a cationic polyacrylamide flocculant with a dosing of approximately 22 mg flocculant/g insoluble solids at an approximate pH of 3. With cake washing, sugar recovery exceeded 90 percent with asymptotic yield at 15 L wash water/kg insoluble solids.

  13. Use of natural zeolite at different doses and dosage procedures in batch and continuous anaerobic digestion of synthetic and swine wastes

    Energy Technology Data Exchange (ETDEWEB)

    Montalvo, S. [Centro de Estudio de Tecnologias Energeticas Renovables (CETER), Instituto Superior Politecnico Jose Antonio Echeverria (ISPJAE), Avenida 127 s/n, CUJAE, Marianao, Ciudad de la Habana (Cuba); Guerrero, L. [Departamento de Procesos Quimicos, Biotecnologicos y Ambientales, Universidad Tecnica Federico Santa Maria, Valparaiso (Chile); Borja, R.; Travieso, L.; Sanchez, E. [Instituto de la Grasa, CSIC, Avda Padre Garcia Tejero 4, 41012, Sevilla (Spain); Diaz, F. [Facultad de Ingenieria Quimica, ISPJAE, Avenida 127 s/n, CUJAE, Marianao, Ciudad de la Habana (Cuba)

    2006-05-15

    The aim of the present work was to study the behavior of conventional digesters working while adding natural zeolite to the anaerobic treatment of swine wastes. High nitrogen concentrations (3g/l) were also applied when synthetic media was used as feed in anaerobic reactors operating in batch mode. Three sets of experiments were carried out. The first experiment was carried out in batch mode, in order to find the most appropriate zeolite doses for the digester operation. One gram per litre of zeolite was found to be the dose that produced the best reactor performance. The second experiment was carried out using three reactors operating with swine wastes at three different hydraulic retention times (HRT): 10, 20 and 30 days. From this experiment, an HRT of 20 days was selected for the following continuous experiments. For the third experiment, the digesters operated in four different ways using synthetic waste and a zeolite dose of 1g/l, with different procedures for zeolite addition: (1) not adding natural zeolite; (2) adding zeolite at the start-up of anaerobic digestion; (3) adding natural zeolite at the start-up of the anaerobic digestion and again when the steady-state was reached; (4) adding natural zeolite on a daily basis. Finally, from these results, a fourth experiment was carried out using swine waste and the same zeolite doses and digesters, operating: (1) without adding natural zeolite; (2) adding natural zeolite at the start-up of the digestion; (3) adding natural zeolite on a daily basis. It was found that the application of natural zeolite allowed for a 17-20% increase in organic matter removal with respect to the experiments carried out where natural zeolite was not added. A daily methane production increase of 11.1-30.8% with respect to the reactors working where no natural zeolite was added. The daily addition of zeolite with the influent fed to the digesters was found to be the most appropriate procedure for dosage of this material on the basis

  14. Impact of microwave pre-treatment on the batch anaerobic digestion of two-phase olive mill solid residue: a kinetic approach

    Directory of Open Access Journals (Sweden)

    B. Rincón

    2016-12-01

    Full Text Available The effect of a microwave (MW pre-treatment on two-phase olive mill solid residue (OMSR or alperujo with a view to enhancing its anaerobic digestibility was studied. The MW pre-treatment was carried out at a power of 800 W and at a targeted temperature of 50 °C using different heating rates and holding times. The following specific energies were applied: 4377 kJ·kg TS-1 (MW1, 4830 kJ·kg TS-1 (MW2, 7170 kJ·kg TS-1 (MW3 and 7660 kJ·kg TS-1 (MW4. The maximum methane yield, 395±1 mL CH4·g VSadded-1, was obtained for MW4. The effect of the pre-treatment on the kinetics of the process was also studied. The methane production curves generated during the batch tests showed a first exponential stage and a second sigmoidal stage for all the cases studied. In the first stage, the kinetic constant for the pre-treatment MW1 was 54.8% higher than that obtained for untreated OMSR.

  15. [Determination of 8 trace elements in mantle muscle and cuttlebone of Sepiella maindroni by ICP-MS using microwave digestion for sample preparation].

    Science.gov (United States)

    Wu, Chang-Wen; Chi, Chang-Feng; He, Guang-Yuan; Xu, Mei-Ying

    2009-12-01

    An inductively coupled plasma mass spectrometry (ICP-MS) for determination of the contents of 8 trace elements in mantle muscle and cuttlebone of Sepiella maindroni after microwave digestion of the sample has been developed. Satisfactory linearity of working curves for the 8 elements was obtained, giving all their correlation coefficients over 0.997 3. The precision of measurement ranges from 2.4% to 8.7% in terms of relative standard deviation. The recoveries and the limits of detection are in the range of 96.5%-106.3% and 0.002-0.032 microg x L(-1), respectively. It was indicated that the proposed method had the advantages of simplicity, speediness and sensitivity. The results showed that the mantle muscle and cuttlebone of Sepiella maindroni contained rich trace elements Zn and Cu, but the contents of Cd and As are higher than the limits of Chinese Pharmacopoeia, Green Trade Standard for Importing and Exporting Medicinal Plant and Preparation and U.S. Food and Drug Standard. Furthermore, our study provides new scientific foundation for the quality control, culture, general application, resource utilization and exporting of Sepiella maindroni.

  16. Chemically coupled microwave and ultrasonic pre-hydrolysis of pulp and paper mill waste-activated sludge: effect on sludge solubilisation and anaerobic digestion.

    Science.gov (United States)

    Tyagi, Vinay Kumar; Lo, Shang-Lien; Rajpal, Ankur

    2014-05-01

    The effects of alkali-enhanced microwave (MW; 50-175 °C) and ultrasonic (US) (0.75 W/mL, 15-60 min) pretreatments, on solubilisation and subsequent anaerobic digestion efficiency of pulp and paper mill waste-activated sludge, were investigated. Improvements in total chemical oxygen demand and volatile suspended solids (VSS) solubilisation were limited to 33 and 39 % in MW pretreatment only (175 °C). It reached 78 and 66 % in combined MW-alkali pretreatment (pH 12 + 175 °C), respectively. Similarly, chemical oxygen demand and VSS solubilisation were 58 and 37 % in US pretreatment alone (60 min) and it improved by 66 and 49 % after US-alkali pretreatment (pH 12 + 60 min), respectively. The biogas yield for US 60 min-alkali (pH 12)-pretreated sludge was significantly improved by 47 and 20 % over the control and US 60 reactors, respectively. The biogas generation for MW (150 °C)-alkali (pH 12)-pretreated sludge was only 6.3 % higher than control; however, it was 8.3 % lower than the MW (150 °C) reactor, which was due to the inhibition of anaerobic activity under harsh thermal-alkali treatment condition.

  17. Determination of minor and trace elements in aromatic spices by micro-wave assisted digestion and inductively coupled plasma-mass spectrometry.

    Science.gov (United States)

    Khan, Naeem; Choi, Ji Yeon; Nho, Eun Yeong; Jamila, Nargis; Habte, Girum; Hong, Joon Ho; Hwang, In Min; Kim, Kyong Su

    2014-09-01

    This study aimed at analyzing the concentrations of 23 minor and trace elements in aromatic spices by inductively coupled plasma-mass spectrometry (ICP-MS), after wet digestion by microwave system. The analytical method was validated by linearity, detection limits, precision, accuracy and recovery experiments, obtaining satisfactory values in all cases. Results indicated the presence of variable amounts of both minor and trace elements in the selected aromatic spices. Manganese was high in cinnamon (879.8 μg/g) followed by cardamom (758.1 μg/g) and clove (649.9 μg/g), strontium and zinc were high in ajwain (489.9 μg/g and 84.95 μg/g, respectively), while copper was high in mango powder (77.68 μg/g). On the whole some of the minor and essential trace elements were found to have good nutritional contribution in accordance to RDA. The levels of toxic trace elements, including As, Cd, and Pb were very low and did not found to pose any threat to consumers.

  18. Determination of 14 Elements in the Body Fluid and Hair of Lung Cancer Patients by Microwave Digestion with ICP-MS

    Directory of Open Access Journals (Sweden)

    Linlin DOU

    2010-08-01

    Full Text Available Background and objective The trace element contents in the body fluid and hair are the important monitoring indicators for many diseases. The analysis of the trace element contents in the samples of lung cancer patients is helpful to the early diagnosis and treatment effectiveness evaluation to the patients. The aim of this study is to develop an ICPMS method for the determination of Cr, Fe, Mn, Al, Cd, Cu, Zn, Ni, Se, Pb, Ca, Mg, Sr, P in the body fluid and hair of lung cancer patients. Methods Samples of body fluid and hair from lung cancer patients were digested with microwave and 14 trace elements were determined with inductively coupled plasma mass spectrometry. Results GBW09101 standard reference material of human hair was used to validate the accuracy of the established method, and the results indicated that there is no obvious difference between the measured values and the references values. Forty-eight samples from 16 lung cancer patients were analyzed with the established method, and several generalizations were discovered. Conclusion The established method can be used for the multielement simultaneous determination of the samples of lung cancer patients, which are helpful to the diagnosis and treatment of the lung cancer.

  19. Investigation of Trace Element Content in the Seeds, Pulp, and Peel of Mashui Oranges Using Microwave Digestion and ICP-MS Analysis.

    Science.gov (United States)

    Chen, Lingyun; Shen, Mei; Ma, Ande; Han, Weili

    2017-06-16

    Fresh Mashui orange samples were pretreated with microwave digestion using an HNO3-H2O2 system. The levels of Mg, K, Ca, Fe, Mn, Cu, Zn, As, Cd, and Pb in the seeds, pulp, and peel were then determined using inductively coupled plasma mass spectrometry (ICP-MS) combined with collision cell technology (CCT) and kinetic energy discrimination (KED). The standard curve coefficient of determinations of the ten tested elements were between 0.9995 and 0.9999. The instrument detection limit was between 0.112 ng/L and 3.05 ng/mL. The method detection limit was between 0.0281 and 763 ng/g. The average recovery rate was between 85.0 and 117%. The current results showed that Mashui oranges are rich in three elements, namely Mg, K, and Ca. The concentrations of K and Ca were significantly higher than that of Mg in the peel. The content of K was the highest in the seeds. Fe, Mn, Cu, and Zn had the second highest concentrations, and Fe was the highest in the seeds, while Cu was the lowest in the peel. As, Cd, and Pb (hazardous elements) had the lowest concentrations of all the tested elements.

  20. Rapid and simultaneous determination of essential minerals and trace elements in human milk by improved flame atomic absorption spectroscopy (FAAS) with microwave digestion.

    Science.gov (United States)

    Luo, Yang; Zhang, Bo; Chen, Ming; Wang, Jue; Zhang, Xue; Gao, Wei-Yin; Huang, Jun-Fu; Fu, Wei-Ling

    2010-09-08

    A method for the simultaneous and economical determination of many trace elements in human milk is developed. Two multi-element hollow cathode lamps (HCLs) were used instead of single-element HCLs to improve the sample throughput of flame atomic absorption spectroscopy (FAAS). The microwave digestion of milk is optimized prior to detection, and the performance characteristics of the improved analysis method are identified. Clinical samples are detected by both FAAS and inductively coupled plasma-optical emission spectroscopy (ICP-OES) for methodology evaluation. Results reveal that the proposed FAAS with multi-element HCLs could determine six essential minerals and trace elements within 15 min. This method provides a linear analytical range of 0.01-10 mg L(-1). For Ca, Cu, Fe, Mg, Mn, and Zn, the limits of determination are 1.5, 3, 1.8, 2.2, 2.1, and 1.3 microg L(-1), respectively. The mean relative standard deviations (RSDs) of intra- and interassays are lower than 7%. Excellent operational characteristics of rapidity, simplicity, and economy make the proposed method a promising one for the quantification of trace elements in human milk in clinics of underdeveloped areas.

  1. Optimization of microwave processing procedure of semen raphani by uniform-design%均匀设计优选莱菔子微波炮制工艺

    Institute of Scientific and Technical Information of China (English)

    李彦博; 孙静

    2011-01-01

    目的 优选莱菔子微波炮制的最佳工艺.方法 以微波火力和加热时间为变量,采用均匀实验设计,以外观性状、水溶性浸出物、醇溶性浸出物、脂肪油和芥子碱硫氰酸盐含量为考察指标.结果 莱菔子微波炮制的最佳工艺为微波大火力,加热3 min.结论 微波法炮制莱菔子合理、稳定、可行.%Objective To select the best microwave processing procedure of semen raphani. Methods The u-niform-design was used with the variables of microwave power and heating time, on the basis of the indexes of macro-scopical character, water-soluble extractives, ethanol-soluble extractives, fatty oil content and Sinapine thiocyanate content. Results The best microwave process of semen raphani was strong microwave power and heating for 3 min. Conclusion The Microwave processing procedure of semen raphani is proved to be reasonable, stable and feasible.

  2. Evaluation of digestion procedures in Kjeldahl method to quantify total nitrogen in analyses applied to animal nutrition

    Directory of Open Access Journals (Sweden)

    Tadeu Eder da Silva

    2016-01-01

    Full Text Available The effects of the salt-to-metal catalyst ratio and amount of digestion mixture on total nitrogen content in different materials using the Kjeldahl method were evaluated. Four samples with low nitrogen contents and four samples with high nitrogen contents were analyzed. The study evaluated two ratios of salt (sodium sulfate to metal catalyst (copper sulfate in the digestion mixture (10:1 and 20:1 and three amounts of digestion mixture per sample (1.0, 1.5, and 2.0 g 200 mg-1. There was an interaction between low-nitrogen material and amount of digestion mixture on nitrogen contents. Samples of cattle feces and corn presented higher nitrogen content when 1.5 and 2.0 g of digestion mixture were used. The high-nitrogen materials presented higher nitrogen contents when 2.0 g of the digestion mixture was used. However, there was an interaction between high-nitrogen material and the ratio of the digestion mixture components. The cattle carcass sample showed higher nitrogen content when the 20:1 ratio was used. The digestion mixture amount in the Kjeldahl method must be 2.0 g with a salt-to-metal catalyst ratio of 20:1 when samples of approximately 200 mg are analyzed.

  3. Microwave-assisted versus conventional decomposition procedures applied to a ceramic potsherd standard reference material by inductively coupled plasma atomic emission spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Papadopoulou, D.N.; Zachariadis, G.A.; Anthemidis, A.N.; Tsirliganis, N.C.; Stratis, J.A

    2004-03-03

    Inductively coupled plasma atomic emission spectrometry (ICP-AES) is a powerful, sensitive analytical technique with numerous applications in chemical characterization including that of ancient pottery, mainly due to its multi-element character, and the relatively short time required for the analysis. A critical step in characterization studies of ancient pottery is the selection of a suitable decomposition procedure for the ceramic matrix. The current work presents the results of a comparative study of six decomposition procedures applied on a standard ceramic potsherd reference material, SARM 69. The investigated decomposition procedures included three microwave-assisted decomposition procedures, one wet decomposition (WD) procedure by conventional heating, one combined microwave-assisted and conventional heating WD procedure, and one fusion procedure. Chemical analysis was carried out by ICP-AES. Five major (Si, Al, Fe, Ca, Mg), three minor (Mn, Ba, Ti) and two trace (Cu, Co) elements were determined and compared with their certified values. Quantitation was performed at two different spectral lines for each element and multi-element matrix-matched calibration standards were used. The recovery values for the six decomposition procedures ranged between 75 and 110% with a few notable exceptions. Data were processed statistically in order to evaluate the investigated decomposition procedures in terms of recovery, accuracy and precision, and eventually select the most appropriate one for ancient pottery analysis.

  4. Accelerating the cosmic microwave background map-making procedure through preconditioning

    Science.gov (United States)

    Szydlarski, M.; Grigori, L.; Stompor, R.

    2014-12-01

    Estimation of the sky signal from sequences of time ordered data is one of the key steps in cosmic microwave background (CMB) data analysis, commonly referred to as the map-making problem. Some of the most popular and general methods proposed for this problem involve solving generalised least-squares (GLS) equations with non-diagonal noise weights given by a block-diagonal matrix with Toeplitz blocks. In this work, we study new map-making solvers potentially suitable for applications to the largest anticipated data sets. They are based on iterative conjugate gradient (CG) approaches enhanced with novel, parallel, two-level preconditioners. We apply the proposed solvers to examples of simulated non-polarised and polarised CMB observations and a set of idealised scanning strategies with sky coverage ranging from a nearly full sky down to small sky patches. We discuss their implementation for massively parallel computational platforms and their performance for a broad range of parameters that characterise the simulated data sets in detail. We find that our best new solver can outperform carefully optimised standard solvers used today by a factor of as much as five in terms of the convergence rate and a factor of up to four in terms of the time to solution, without significantly increasing the memory consumption and the volume of inter-processor communication. The performance of the new algorithms is also found to be more stable and robust and less dependent on specific characteristics of the analysed data set. We therefore conclude that the proposed approaches are well suited to address successfully challenges posed by new and forthcoming CMB data sets.

  5. Bioparticles coated with an ionic liquid for the pre-concentration of rare earth elements from microwave-digested tea samples and the subsequent quantification by ETV-ICP-OES† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c6ay02189a Click here for additional data file.

    Science.gov (United States)

    Hosseinzadegan, Sara; Nischkauer, Winfried; Bica, Katharina

    2016-01-01

    An analytical procedure for straight-forward quantification of rare earth elements (REEs) in tea was developed. The method consists of three steps: first, dry tea powder is converted into an aqueous sample solution using a microwave-assisted digestion procedure. Then, the REEs are retained on newly designed sorbent particles and are thus effectively extracted from the sample digest. Then, the REE-loaded sorbent material is introduced into the furnace of an electro-thermal vaporization (ETV) unit. There, the core of the particles is pyrolyzed and removed in a first temperature step. Then, the REE analytes are swiftly evaporated at high temperatures, and subsequently analyzed by ICP-OES. The advantages of the method proposed here are as follows: extraction of REEs is accomplished via “dispersed particle extraction”; this avoids typical shortcomings of conventional solid-phase extraction. The analysis via ETV allows separation of the sorbent particles from the analytes in time. Thus, detrimental effects of plasma-loading are circumvented. The method was shown to provide satisfactory detection limits of typically 50 ng g–1 in the dry tea samples (3 s criterion). The method was validated by means of spike recovery experiments, and applied to the analysis of ten different tea samples from China, Japan and India, as sold in European markets.

  6. Processing effects on susceptibility of starch to digestion in some dietary starch sources.

    Science.gov (United States)

    Niba, Lorraine L

    2003-01-01

    Maize flour, potato flour, cocoyam flour, plantain flour, yam flour, and rice flour were assayed for starch digestibility by an established enzymatic procedure. These were either autoclaved, microwaved, or parboiled and then freeze-dried. Freeze-dried samples were stored for 10 days either below freezing or at ambient temperature. Parameters assessed were readily digestible starch (RDS), slowly digestible starch (SDS), and total starch (TS). Data was analyzed by t-test (P plantain flour to 68.4 g/100 g in rice flour. Autoclaving resulted in reduced TS levels insome flours. Moist heat processing and the post-process storage temperature therefore result in significant changes in starch susceptibility to enzymic digestion. This information will be useful in developing food processing and storage procedures that modify starch resistance to digestion in order to optimize its nutritional quality and to enhance the physiological benefits.

  7. The determination of trace element concentrations in fly ash samples using ultrasound-assisted digestion followed with inductively coupled plasma optical emission spectrometry.

    Science.gov (United States)

    Ilander, Aki; Väisänen, Ari

    2009-08-01

    A method of ultrasound-assisted digestion followed by inductively coupled plasma optical emission spectrometry (ICP-OES) used for the determination of trace element (chromium, copper, lead, nickel, vanadium and zinc) concentrations in fly ash samples was developed. All the measurements were performed in robust plasma conditions. Ultrasound-assisted digestion procedures using digestion solutions of aqua regia and hydrofluoric acid (HF) resulted in recovery rates of over 80% for all the analyte elements. Ultrasound-assisted two-step digestion with digestion solutions of 6mL of HNO(3) (Step 1) and 3mL of HNO(3)+3mL of HF (Step 2) resulted in recovery rates of over 92% for all the analyte elements with one exception, chromium, which had a recovery of about 85%. The analysis of SRM 1633b showed that the two-step ultrasound-assisted digestion method developed resulted in chromium, copper, nickel and zinc concentrations higher than the microwave digestion method standardized by the United States Environmental Protection Agency (USEPA method 3052). This is the very first time when a digestion method using ultrasound resulted in higher efficiency than microwave (USEPA method 3052) for chromium and nickel in very hard to dissolve samples. The major advantages of the ultrasound-assisted digestion over microwave digestion is the high treatment rate (about 30 samples simultaneously with a sonication time of 18min) and the possibility to use new sample vessels without a significant increase in costs.

  8. Identification of protein SUMOylation sites by mass spectrometry using combined microwave-assisted aspartic acid cleavage and tryptic digestion

    Science.gov (United States)

    Osula, Omoruyi; Swatkoski, Stephen; Cotter, Robert J.

    2012-01-01

    SUMO (Small-Ubiquitin-like MOdifier) is a post-translational modifier of protein substrates at lysine residues that conjugates to proteins in response to various changes in the cell. As a result of SUMO modification, marked changes in transcription regulation, DNA repair, subcellular localization, and mitosis, among other cellular processes, are known to occur. However, while the identification of ubiquitylation sites by mass spectrometry is aided in part by the presence of a small di-amino acid GlyGly “tag” that remains on lysine residues following tryptic digestion, SUMOylation poses a particular challenge as the absence of a basic residue near to the SUMO C-terminus results in a significant 27 or 32 amino acid sequence branch conjugated to the substrate peptide. MS/MS analyses of these branch peptides generally reveal abundant fragment ions resulting from cleavage of the SUMO tail, but which obscure those needed for characterizing the target peptide sequence. Other approaches for identifying SUMO substrates exist and include overexpression of the SUMO isoforms using an N-terminal histidine tag, as well as site-directed mutagenesis of the C-terminal end of the SUMO sequence. Here, we employ combined enzymatic/chemical approaches which serve to shorten the SUMO tag, and thus help to simplify SUMO spectra, making interpretation of mass spectra and location of the SUMOylation site easier. As described in this report, we demonstrate a method for identifying SUMOylation sites using three commercially available SUMO- modified isoforms, and by employing acid-only and acid/trypsin cleavage strategies. These approaches were carried out using MALDI-TOF and LC/MS instrumentation, along with CID and ETD fragmentation. PMID:22576878

  9. Microwave digestion polarography for determining seven trace elements in Salvia Miltiorrhiza Root and compound Salvia Miltiorrhiza Root injection simultaneously

    Institute of Scientific and Technical Information of China (English)

    HUANG Yi; ZHANG Tai-ming; GAO Juan; LIANG Yi-zeng

    2007-01-01

    The sensitive second derivative waves of Cu(Ⅱ), Pb( Ⅱ ), Cd( Ⅱ ), Ni( Ⅱ ), Zn( Ⅱ ), Fe( Ⅱ ) and Mn( Ⅱ ), forming in the substrate solution (pH=9.26) consisting of ammonia, ammonium chlorid, gelatin and ascorbic acid were researched. The peak potentials of the polarographic waves of the seven ions are at about -0.48, -0.63, -0.79, -1.04, -1.28, -1.44 and -1.60 V respectively. Combining with microwave, technique, a new method for the simultaneous determination of the seven trace elements in Chinese traditional medicine was developed. The method is easy to operate, rapid, simple and convenient. When the signal-to-noise rate equals 3, the detection limits of Cu, Pb, Cd, Ni, Zn, Fe and Mn are 4.2 × 10-3, 5.3 × 10-3, 2.1 × 10-3, 5.8 × 10-4, 3.0 × 10-3,7.7 × 10-4 and 1.1 × 10-3 μg/mL respectively. Well linear relationships exist between the concentrations and the peak currents when Cu, Pb, Cd, Ni, Zn, Fe and Mn concentrations are within 8.5× 10-3-10, 9.7×10-3-10, 4.5×10 3-10, 1.2× 10-3-10, 6.4× 10-3-10,1.5 × 10-3-10 and 2.8 × 10-3-10 μg/mL, respectively. The method has been used to the simultaneous determination of the seven trace elements in Salvia Miltiorrhiza Root and compound Salvia Miltiorrhiza Root injection, the relative standard deviations(RSDs) of the Cu, Pb, Cd, Ni, Zn, Fe and Mn in the two medicines are 3.9% and 5.8%, 4.0% and 4.1%, 4.3% and 5.7%, 4.9% and 5.3%, 4.4% and 4,7%, 3.5% and 4.0%, 0.51% and 2.8%, respectively; the comparisons of the determination results with the values obtained by the standard method indicate that the presented method has very well veracity.

  10. A generic and systematic procedure to derive a simplified model from the Anaerobic Digestion Model No. 1 (ADM1)

    OpenAIRE

    Ficara, E.; Leva, A.; Harmand, Jérôme

    2015-01-01

    The Anaerobic Digestion Model No.1 (ADM1) developed by the IWA Task Group for mathematical modelling of anaerobic digestion processes (Batstone et al. (2001) [1]) is a structural model which describes the main biochemical and physicochemical processes. For such purposes, other models have been proposed to describe anaerobic processes with a reduced set of parameters, state variables and processes. Among them, the Anaerobic Model No. 2 (AM2) proposed by Bernard et al. (2001) [2] which describe...

  11. 微波消解--FAAS测定佛手中的微量元素%Determination of Microelements in Bergamot by Microwave Digestion-FAAS

    Institute of Scientific and Technical Information of China (English)

    秦书芝; 赵成国; 张瑶; 夏婷; 肖洪彬

    2014-01-01

    目的:测定佛手中锌(Zn)、铜(Cu)、锰(Mn)、铁(Fe)4种微量元素的含量。方法:采用微波消解法处理佛手,利用火焰原子吸收法对佛手中Zn、Cu、Mn、Fe 4种微量元素含量进行测定分析。结果:佛手中Zn、Cu、Mn、Fe含量分别为23.33、4.51、12.13、138.54μg/g。结论:火焰原子吸收光谱法简单、准确,方法加标回收率在98.9%~101.3%,相对标准偏差(RSD)在0.38%~1.06%之间。%Objective:To determine the contents of Zn, Cu, Mn and Fe contained in bergamot. Methods:Berg-amot was dealt by microwave digestion method, the contents of Zn, Cu, Mn and Fe contained in bergamot were de-termined and analyzed by flame atomic absorption method(FAAS). Results:The contents of Zn, Cu, Mn and Fe con-tained in bergamot were 23.33, 4.51, 12.13 and 138.54μg/g respectively. Conclusion:The method is simple and ac-curate, the recovery rate of the method is over the range of 98.9%to 101.3%, and RSD over the range of 0.38%to 1.06%.

  12. 微波消解-分光光度法测定农用粉煤灰中的硼%Determination of Boron in Fly Ash for Agricultural Use by Microwave Digestion-Spectrophotometry

    Institute of Scientific and Technical Information of China (English)

    徐玉宏; 张静; 王静媛; 邓晓蓓

    2009-01-01

    研究了分光光度法测定农用粉煤灰中硼时样品的微波消解方法,建立了合理的分析步骤.试验结果表明:微波完全消解粉煤灰仅需25 min,相对标准偏差5.8% ~ 7.3%,其方法的加标回收率为94% ~ 109%.结果表明,微波消解-分光光度法是测定粉煤灰中硼的一种快速、准确且低环境污染的方法.%Digestion of fly ash for agricultural use by heating with microwave was studied for the spectrophotometric method of boron determination, and the effective analysis approach was established. The results showed that: The sample could be digested completely in 25 minutes, the relative standard deviation ranged from 5.38% to 7.3% and the recovery from 94% to 109%. It proves that microwave digestion-spectrophotometric method for determining boron in fly ash is rapid, accurate and less environmental contamination method.

  13. Improvement of AOAC Official Method 984.27 for the determination of nine nutritional elements in food products by Inductively coupled plasma-atomic emission spectroscopy after microwave digestion: single-laboratory validation and ring trial.

    Science.gov (United States)

    Poitevin, Eric; Nicolas, Marine; Graveleau, Laetitia; Richoz, Janique; Andrey, Daniel; Monard, Florence

    2009-01-01

    A single-laboratory validation (SLV) and a ring trial (RT) were undertaken to determine nine nutritional elements in food products by inductively coupled plasma-atomic emission spectroscopy in order to improve and update AOAC Official Method 984.27. The improvements involved optimized microwave digestion, selected analytical lines, internal standardization, and ion buffering. Simultaneous determination of nine elements (calcium, copper, iron, potassium, magnesium, manganese, sodium, phosphorus, and zinc) was made in food products. Sample digestion was performed through wet digestion of food samples by microwave technology with either closed or open vessel systems. Validation was performed to characterize the method for selectivity, sensitivity, linearity, accuracy, precision, recovery, ruggedness, and uncertainty. The robustness and efficiency of this method was proved through a successful internal RT using experienced food industry laboratories. Performance characteristics are reported for 13 certified and in-house reference materials, populating the AOAC triangle food sectors, which fulfilled AOAC criteria and recommendations for accuracy (trueness, recovery, and z-scores) and precision (repeatability and reproducibility RSD and HorRat values) regarding SLV and RT. This multielemental method is cost-efficient, time-saving, accurate, and fit-for-purpose according to ISO 17025 Norm and AOAC acceptability criteria, and is proposed as an improved version of AOAC Official Method 984.27 for fortified food products, including infant formula.

  14. Evaluation of microwave and ultrasound extraction procedures for arsenic speciation in bivalve mollusks by liquid chromatography–inductively coupled plasma-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Clarissa M.M.; Nunes, Matheus A.G. [Departamento de Química, Universidade Federal de Santa Maria, Santa Maria, RS (Brazil); Barbosa, Isa S.; Santos, Gabriel L. [Instituto de Química, Universidade Federal da Bahia, Salvador, BA (Brazil); Peso-Aguiar, Marlene C. [Instituto de Biologia, Universidade Federal da Bahia, Salvador, BA (Brazil); Korn, Maria G.A. [Instituto de Química, Universidade Federal da Bahia, Salvador, BA (Brazil); Flores, Erico M.M. [Departamento de Química, Universidade Federal de Santa Maria, Santa Maria, RS (Brazil); Dressler, Valderi L., E-mail: vdressler@gmail.com [Departamento de Química, Universidade Federal de Santa Maria, Santa Maria, RS (Brazil)

    2013-08-01

    Liquid chromatography–inductively coupled plasma-mass spectrometry (LC–ICP-MS) was used for arsenic speciation analysis in tissues of bivalve mollusks (Anomalocardia brasiliana sp. and Macoma constricta sp.). Microwave and ultrasound radiation, combined with different extraction conditions (solvent, sample amount, time, and temperature), were evaluated for As-species extraction from the mollusks' tissues. Accuracy, extraction efficiency, and the stability of As species were evaluated by analyzing certified reference materials (DORM-2, dogfish muscle; BCR-627, tuna fish tissue; and SRM 1566b, oyster tissue) and analyte recovery tests. The best conditions were found to be microwave-assisted extraction using 200 mg of samples and water at 80 °C for 6 min. The agreement of As-species concentration in samples ranged from 97% to 102%. Arsenobetaine (AsB) was the main species present in bivalve mollusk tissues, while monomethylarsonic acid (MMA) and arsenate (As(V)) were below the limit of quantification (0.001 and 0.003 μg g{sup −1}, respectively). Two unidentified As species also were detected and quantified. The sum of the As-species concentration was in agreement (90 to 104%), with the total As content determined by ICP-MS after sample digestion. - Highlights: • Method development for As speciation analysis by LC–ICP-MS • Evaluation of microwave and ultrasonic radiation for sample preparation • Investigation on As species content in mollusks.

  15. Impact of a yogurt matrix and cell microencapsulation on the survival of Lactobacillus reuteri in three in vitro gastric digestion procedures.

    Science.gov (United States)

    Champagne, C P; Raymond, Y; Guertin, N; Martoni, C J; Jones, M L; Mainville, I; Arcand, Y

    2015-01-01

    The goal of this study was to assess the interaction between microencapsulation and a yogurt food matrix on the survival of Lactobacillus reuteri NCIMB 30242 in four different in vitro systems that simulate a gastric environment. The four systems were: United States Pharmacopeia (USP) solutions, a static two-step (STS) procedure which included simulated food ingredients, a constantly dynamic digestion procedure (IViDiS), as well a multi-step dynamic digestion scheme (S'IViDiS). The pH profiles of the various procedures varied between systems with acidity levels being: USP > STS > IViDiS = S'IVIDiS. Addition of a food matrix increased the pH in all systems except for the USP methodology. Microencapsulation in alginate-based gels was effective in protecting the cells in model solutions when no food ingredients were present. The stability of the probiotic culture in the in vitro gastric environments was enhanced when (1) yoghurt or simulated food ingredient were present in the medium in sufficient quantity, (2) pH was higher. The procedure-comparison data of this study will be helpful in interpreting the literature with respect to viable counts of probiotics obtained from different static or dynamic in vitro gastric systems.

  16. Determination of Cadmium Content in Leather Products by Microwave Digestion and ICP-MS%微波消解ICP-MS测定皮革制品中镉含量

    Institute of Scientific and Technical Information of China (English)

    郑锦文

    2014-01-01

    This paper tells the determination of cadmium content in leather goods by using microwave di-gestion and ICP-MS. Reasons for the difference results between the isotopes of cadmium in 111 and 114 Cd content are guarantee reagent hydrogen peroxide which is used in the microwave digestion. Hydrogen peroxide contains 300-700 ng/mL tin, which increases the background of the curve, and contributes differ-ently to the content of cadmium isotopes in leather products; In order to get same testing result of 111 Cd and 114 Cd content in leather products, no hydrogen peroxide by only nitric acid should be used in mi-crowave digestions.%讲述了用微波消解ICP-MS测定皮革制品中镉含量时,镉的同位素111Cd与114Cd测定结果出现差异的原因:是微波消解时使用了2 mL优级纯的过氧化氢,过氧化氢中锡元素的本底含量高,含300~700 ng/mL,对皮革制品中镉的贡献不一;解决111Cd与114Cd测定结果的差异的方法:微波消解时可不使用过氧化氢,只用硝酸进行微波消解处理。

  17. Determination of Nine Elements in Chicken by ICP-AES with Microwave Digestion%微波消解-电感耦合等离子发射光谱测定鸡肉中9种元素

    Institute of Scientific and Technical Information of China (English)

    张洁; 陈玎玎; 祁克宗; 徐艳秋

    2012-01-01

    建立微波消解-电感耦合等离子发射光谱测定鸡肉中Ca、Fe、Zn、Se、Ni、Mn、Cu、Pb、灿九种元素的方法。测定结果表明,此方法的检出限为0.0004-0.0069mg/L,相对标准偏差O扛3)为0.72%-4.10%,回收率为80.0%-107.1%。同时研究微波消解试剂的种类和加入量、微波消解升温程序对测定结果的影响;并且将微波消解与干灰化法、湿法消解进行比较,结果显示,经微波消解后,测得多种元素的值显著性高于干法灰化、湿法消解(P〈0.05)。%A method was established to determine calcium, ferrum, zinc, selenium, nickel, manganese, copper, lead and arsenic in chicken using microwave digestion followed by inductively coupled plasma-atomic emission spectrometry (ICP- AES). The limit of detection of this method was 0.4-6.9 ng/mL, and the precision (RSD) for three replicate determinations ranged from 0.72% to 4.10%. Average recoveries of 9 elements in chicken reference material and commercial chicken varied from 80.0% and 107.1%. The effects of digestion agent type and dosage and programmed heating on results of determination were investigated. Significantly higher results of determination were obtained with microwave digestion when compared with dry ashing and wet digestion (P〈0.05).

  18. 利用微波消解-无银催化法检测水中化学需氧量%Detection of chemical oxygen demand (CODcr) in water with silver-free catalyst by microwave digestion method

    Institute of Scientific and Technical Information of China (English)

    薛文平; 刘文伟; 黄德智; 元世勇

    2011-01-01

    研究了采用微波消解-无银催化测定CODCr的新方法,并探讨了该方法测定CODCr时样品消解条件对检测结果的影响;实验还采用硫酸锰、硫酸镍、硫酸铜、硫酸镁、硫酸铁分别作催化剂,微波加热快速消解后测定CODCr,同时与国家标准方法测定结果进行比较,确定了最佳催化剂、最佳投加量和消解时间.对比结果表明:当试样体积为5 mL时,O.250 mol/L K2 Cr2O7的用量为5 mL,硫酸锰催化剂用量为3 mg,微波消解时间仅为3 min,检测结果最佳.该方法具有快速准确、节约试剂、降低耗电成本等优点.%This paper studied a new method for determining CODcr with silver-free catalyst by microwave digestion method and discussed the influences of digestion conditions on the detection results.This experiment used manganese sulfate, nickel sulfate, cupric sulfate, magnesium sulfate and ferric sulfate as catalyst respectively, and determined CODcr after microwave fast digestion.By comparing the obtained CODcr value with that determined by the national standard method, the optimal catalyst, dosage and digestion time was determined.Comparative results showed that: when the volume of the sample was 5 mL, the volume of 0.250 mol/L K2Cr2O7 was 5 mL, the amount of manganese sulfate catalyst was 3 mg and the microwave digestion time was 3 min, the results were the best.The method was quick, accurate, low consumption of reagent and power.

  19. Arsenic speciation in rice by capillary electrophoresis/inductively coupled plasma mass spectrometry: enzyme-assisted water-phase microwave digestion.

    Science.gov (United States)

    Qu, Haiou; Mudalige, Thilak K; Linder, Sean W

    2015-04-01

    We report an analytical methodology for the quantification of common arsenic species in rice and rice cereal using capillary electrophoresis coupled with inductively coupled plasma mass spectrometry (CE-ICPMS). An enzyme (i.e., α-amylase)-assisted water-phase microwave extraction procedure was used to extract four common arsenic species, including dimethylarsinic acid (DMA), monomethylarsonic acid (MMA), arsenite [As(III)], and arsenate [As(V)] from the rice matrices. The addition of the enzyme α-amylase during the extraction process was necessary to reduce the sample viscosity, which subsequently increased the injection volume and enhanced the signal response. o-Arsanilic acid (o-ASA) was added to the sample solution as a mobility marker and internal standard. The obtained repeatability [i.e., relative standard deviation (RSD %)] of the four arsenic analytes of interest was less than 1.23% for elution time and 2.91% for peak area. The detection limits were determined to be 0.15-0.27 ng g(-1). Rice standard reference materials SRM 1568b and CRM 7503-a were used to validate this method. The quantitative concentrations of each organic arsenic and summed inorganic arsenic were found within 5% difference of the certified values of the two reference materials.

  20. The Levels of Trace Elements in Honey and Molasses Samples That Were Determined by ICP-OES After Microwave Digestion Method.

    Science.gov (United States)

    Altundag, Huseyin; Bina, Emel; Altıntıg, Esra

    2016-04-01

    The aim of this study is determining the amount of Al, Cu, Fe, Mn, Ni, Pb and Zn in samples of molasses and honey which were gathered from the Sakarya and Istanbul regions. In this study, trace elements in 8 honey and 20 molasses samples with different botanic features were evaluated. The sample preparation phase was performed via wet decomposition method and microwave digestion system. The accuracy of the method was checked by the standard reference material; tea leaves (INCY-TL-1) and NIST-SRM 1515-apple. The concentrations of essential trace elements (TEs) were observed in the range of 1.61 ± 0.01-287.03 ± 1.07; 0.21 ± 0.01-11.04 ± 0.12; 0.35 ± 0.03-21.71 ± 0.02 and 1.19 ± 0.01-60.90 ± 1.09 μg g(-1) for iron, copper, manganese and zinc ions, respectively, while the toxic element contents were observed in the range of 0.82 ± 0.17-3.06 ± 0.03; 0.04 ± 0.05-1.96 ± 0.03 and 0.62 ± 0.01-120.52 ± 0.10 μg g(-1) for lead, nickel and aluminum ions, respectively. The concentrations of basic TEs iron, copper, manganese and zinc were determined as 3.87 ± 0.04-16.76 ± 0.06; 0.45 ± 0.03-2.15 ± 0.01; 0.13 ± 0.01-15.02 ± 0.14 and 0.80 ± 0.09-12.03 ± 0.19 for honey samples. Also, toxic metal, lead, nickel and aluminum values in the honey samples were determined as 1.21 ± 0.12-2.46 ± 0.21; 0.28 ± 0.14-0.88 ± 0.43 and 2.11 ± 0.02-8.04 ± 0.08. A comparison between gathered data and literature values has performed and it is determined that such findings are suitable with the literature.

  1. Environmental biomonitoring of essential and toxic elements in human scalp hair using accelerated microwave-assisted sample digestion and inductively coupled plasma optical emission spectroscopy.

    Science.gov (United States)

    Kumakli, Hope; Duncan, A'ja V; McDaniel, Kiara; Mehari, Tsdale F; Stephenson, Jamira; Maple, Lareisha; Crawford, Zaria; Macemore, Calvin L; Babyak, Carol M; Fakayode, Sayo O

    2017-05-01

    Human scalp hair samples were collected and used to assess exposure to toxic elements and essential elements in the state of North Carolina, USA using accelerated microwave assisted acid digestion and inductively coupled plasma optical emission spectroscopy (ICP-OES). The figures-of-merit of the ICP-OES were appropriate for elemental analysis in scalp hair with detection limits as low as 0.0001 mg/L for Cd, good linearity (R(2) > 0.9978), and percent recoveries that ranged from 96 to 106% for laboratory-fortified-blanks and 88-112% for sample spike recovery study. The concentrations of essential elements in scalp hair were larger than those of toxic elements, with Ca having the highest average concentration (3080 μg/g, s = 14,500, n = 194). Some of the maximum concentrations observed for As (65 μg/g), Ni (331 μg/g), Cd (2.96 μg/g), and Cr (84.6 μg/g) in individual samples were concerning, however. Samples were statistically analyzed to determine the influence of race, gender, smoking habits, or age on the elemental concentrations in scalp hair. Higher concentrations of essential elements were observed in the scalp hair of Caucasians, females, and non-smokers, and the differences were often significant at a 90% confidence level. Several pairs of essential elements, for example Ca-K, Ca-Mg, and Ca-Zn, were strongly correlated in Caucasian hair but uncorrelated in African-American hair. Similarly, essential elements were strongly correlated in female hair but weakly correlated in male hair. Toxic element pairs (As-Cd, As-Se, Pb-As, and Se-Cd) were strongly correlated in the hair of smokers but uncorrelated in that of non-smokers, suggesting that cigarette smoke is a common source of toxic elements in humans. Published by Elsevier Ltd.

  2. Study on high pressure sealed microwave digestion method of copper concentrate samples%铜精矿样品的高压密封微波消解方法研究

    Institute of Scientific and Technical Information of China (English)

    杨丽飞; 苏明跃; 郭芬

    2011-01-01

    A high pressure sealed microwave digestion technique was studied for composition analysis in copper concentrate samples. According to their mineral composition and phase structure,the copper concentrate samples with high content of organic matters, silicon and metallic oxide were used for testing. The experimental content included types and dosage of digestion reagent, the conditions to fully digest the sample, etc. A high pressure sealed microwave digestion method based on the experimental results was established, which was applicable for the chemical composition analysis of copper concentrate. By the complete digestion test of copper concentrate samples with different mineral composition and phase structure, we proved the applicability of this method. The copper concentrate was digested by this method. Then, arsenic, mercury, lead and cadmium were determined by ICP-AES, and fluorine in testing solution was determined by fluorine ion selective electrode method. The analytical results were consistent with those obtained by national standard method.%研究了采用高压密封微波消解技术消解用于成分分析的铜精矿样品的方法.依据铜精矿矿物组成、物相结构,分别选取了有机物含量高、硅含量高和金属氧化物含量高的样品进行试验,试验内容包括消解试剂种类和用量选择,样品完全消解的条件等.根据研究结果建立了适于铜精矿化学成分分析的高压密封微波消解方法.通过对不同矿物组分、不同物相结构的铜精矿样品的完全消解验证实验,证明了该消解方法的实用性.采用该方法消解铜精矿,然后用ICP-AES法检测试液中砷、汞、铅、镉和氟离子选择电极法检测试液中氟,分析结果与国家标准方法的测定结果一致.

  3. Rapid high-performance sample digestion of base metal ores using high-intensity infrared radiation with determination by nitrogen-based microwave plasma optical spectrometry

    Directory of Open Access Journals (Sweden)

    Yong Wang

    2016-03-01

    Full Text Available Infrared sample digestion technology has been rapidly developed in recent years and its application and digestion performance on a variety of ores of base metals was assessed in this study, using a 6-channel infrared digester. Digestion times of 10 min or less were achieved for all base metal ores investigated, including oxides, sulfides, and silicates of Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Ti, W, and Zn. Performance criteria for all samples were excellent, reflected in z values of less than 2 in all cases. Various acid digestion methods were developed for the selected ore samples under high intensity infrared radiation and delivered virtually complete recoveries of all of the elements of interest. Chromite, the notoriously refractory chromium ore was digested within 10 min and gave 100% recovery of chromium. These digestions were accomplished without resorting to perchloric acid and, for most sample types, without hydrofluoric acid, significantly improving the workplace safety for analysts. Between-channel variation of the analyte recoveries from the 6-channel unit were generally below 2%, suggesting that the digestion methods developed with this platform provide reproducible results to meet various sample preparation demands. The high speed and analyte recovery of these digestions makes this methodology especially attractive for prospectors and developers who demand rapid and reliable results from exploration samples.

  4. Element analysis and characteristic identification of non-fumigated and sulfur-fumigated Fritillaria thunbergii Miq. using microwave digestion-inductively coupled plasma atomic emission spectrometry combined with Fourier transform infrared spectrometry

    Directory of Open Access Journals (Sweden)

    Yajing Lou

    2014-01-01

    Full Text Available Background: Sulfur-fumigation may induce chemical transformation of traditional Chinese medicines leading to harmful effects following patient ingestion. For quality control, it is urgently needed to develop a reliable and efficient method for sulfur-fumigation identification. Materials and Methods: The spectrochemical identification of non-fumigated and sulfur-fumigated Fritillaria thunbergii Miq. was carried out to evaluate inorganic elements and organic components. The concentrations of 12 elements, including Zn, Mn, Cu, Fe, Li, Mg, Sr, Pb, As, Cd, Hg, and S of samples were determined by microwave digestion - inductively coupled plasma atomic emission spectrometry (ICP-AES. Meanwhile, Fourier transform infrared spectrometry (FTIR was used for the study of chemical group characteristic reactions after sulfur-fumigation. Results: The concentrations of Fe, Mg, Hg, and S elements showed significant differences between non-fumigated and sulfur-fumigated Fritillaria thunbergii Miq. The characteristic stretching vibrations of some groups in FTIR spectra, such as -OH, -S = O and -S-O, provided the identification basis for the discrimination of non-fumigated and sulfur-fumigated Fritillaria thunbergii Miq. Conclusion: The application of microwave digestion - ICP-AES was successfully used in combination with FTIR to authenticate and evaluate the quality of medicinal Fritillaria thunbergii Miq. Further applications of this technique should be explored.

  5. 微波消解-石墨炉原子吸收光谱法测定儿童发铅%Microwave digestion-graphite furnace atomic absorption spectrometry for the determination of lead in children's hair

    Institute of Scientific and Technical Information of China (English)

    陈宇鸿; 沈仁富

    2012-01-01

    目的:建立发中铅的微波消解-石墨炉原子吸收光谱测定法.方法:样品经微波消解后,石墨炉原子吸收光谱法测定.结果:方法标准曲线相关系数为0.9996,相对标准偏差1.15% ~2.16%,回收率为94.4% ~ 102%.结论:该法准确、灵敏,是高效、快速、实用的测定发中铅的方法.%Objective: To establish microwave digestion - graphite furnace atomic absorption spectrometry for the determination of lead in children's hair. Methods:The samples were digested with microwave oven and determined by graphite furnace atomic absorption spectrometry. Results: The correlation coefficient of the metod was 0. 9996 with RSDs of 1. 15% ~2. 16% and average recoveries of 94.4% ~ 102%. Conclusion: The method is accurate,precisive and sensitive, it is suitable for the determination of lead in hair.

  6. Element analysis and characteristic identification of non-fumigated and sulfur-fumigated Fritillaria thunbergii Miq. using microwave digestion-inductively coupled plasma atomic emission spectrometry combined with Fourier transform infrared spectrometry

    Science.gov (United States)

    Lou, Yajing; Cai, Hao; Liu, Xiao; Tu, Sicong; Pei, Ke; Zhao, Yingying; Cao, Gang; Li, Songlin; Qin, Kunming; Cai, Baochang

    2014-01-01

    Background: Sulfur-fumigation may induce chemical transformation of traditional Chinese medicines leading to harmful effects following patient ingestion. For quality control, it is urgently needed to develop a reliable and efficient method for sulfur-fumigation identification. Materials and Methods: The spectrochemical identification of non-fumigated and sulfur-fumigated Fritillaria thunbergii Miq. was carried out to evaluate inorganic elements and organic components. The concentrations of 12 elements, including Zn, Mn, Cu, Fe, Li, Mg, Sr, Pb, As, Cd, Hg, and S of samples were determined by microwave digestion - inductively coupled plasma atomic emission spectrometry (ICP-AES). Meanwhile, Fourier transform infrared spectrometry (FTIR) was used for the study of chemical group characteristic reactions after sulfur-fumigation. Results: The concentrations of Fe, Mg, Hg, and S elements showed significant differences between non-fumigated and sulfur-fumigated Fritillaria thunbergii Miq. The characteristic stretching vibrations of some groups in FTIR spectra, such as -OH, -S = O and -S-O, provided the identification basis for the discrimination of non-fumigated and sulfur-fumigated Fritillaria thunbergii Miq. Conclusion: The application of microwave digestion - ICP-AES was successfully used in combination with FTIR to authenticate and evaluate the quality of medicinal Fritillaria thunbergii Miq. Further applications of this technique should be explored. PMID:24914306

  7. Determination of the Content of Zinc and Copper in Sewage Sludge by Microwave Digestion-atomic Absorption Method%微波消解-原子吸收法测定污泥中的铜、锌含量

    Institute of Scientific and Technical Information of China (English)

    任旭锋; 王长智; 李娇英

    2015-01-01

    参考环境标准》固体废物镍铜的测定》和》固体废物铅锌隔的测定》优化了原子吸收仪工作参数和微波消解条件,建立了微波消解-原子吸收法测定太阳能电池行业废水处理后污泥中的铜和锌元素的分析方法,方法的检出限范围为0.001~0.009 mg/L,方法加标回收率93.3%~109%,相对标准偏差RSD均小于5%。%An analysis method as microwave digestion-atomic absorption spectroscopy ( ADAAS) was established for the determination of copper and zinc in the sludge from the treatment of solar cell industry wastewater.With reference to the environmental standards of Determination of Nickel and Copper Solid Waste and Determination of Lead, Zinc and Cadmium Solid Waste, the microwave digestion conditions as well as the operating parameters of atomic absorption spectrometer were optimized.The detection limit of this method was in the range of 0.001 ~0.009 mg/L.The relative standard deviation ( RSD) was less than 5%and recoveries were 93.3%~109.0%.

  8. "In situ" extraction of essential oils by use of Dean-Stark glassware and a Vigreux column inside a microwave oven: a procedure for teaching green analytical chemistry.

    Science.gov (United States)

    Chemat, Farid; Perino-Issartier, Sandrine; Petitcolas, Emmanuel; Fernandez, Xavier

    2012-08-01

    One of the principal objectives of sustainable and green processing development remains the dissemination and teaching of green chemistry in colleges, high schools, and academic laboratories. This paper describes simple glassware that illustrates the phenomenon of extraction in a conventional microwave oven as energy source and a process for green analytical chemistry. Simple glassware comprising a Dean-Stark apparatus (for extraction of aromatic plant material and recovery of essential oils and distilled water) and a Vigreux column (as an air-cooled condenser inside the microwave oven) was designed as an in-situ extraction vessel inside a microwave oven. The efficiency of this experiment was validated for extraction of essential oils from 30 g fresh orange peel, a by-product in the production of orange juice. Every laboratory throughout the world can use this equipment. The microwave power is 100 W and the irradiation time 15 min. The method is performed at atmospheric pressure without added solvent or water and furnishes essential oils similar to those obtained by conventional hydro or steam distillation. By use of GC-MS, 22 compounds in orange peel were separated and identified; the main compounds were limonene (72.1%), β-pinene (8.4%), and γ-terpinene (6.9%). This procedure is appropriate for the teaching laboratory, does not require any special microwave equipment, and enables the students to learn the skills of extraction, and chromatographic and spectroscopic analysis. They are also exposed to a dramatic visual example of rapid, sustainable, and green extraction of an essential oil, and are introduced to successful sustainable and green analytical chemistry.

  9. Measurement of Trace Element in Tartary Buckwheat by Flame Atomic Absorption Spectrometry with Microwave Digestion%微波消解火焰原子吸收法测定苦荞中的微量元素

    Institute of Scientific and Technical Information of China (English)

    陈燕芹

    2011-01-01

    [目的]采用微波消解火焰原子吸收法测定苦荞中的微量元素.[方法]用HNO3+H2O2对苦养样品进行微波消解处理,采用火焰原子吸收光谱法测定苦荞消解液中的Fe、Cu、Zn、Mn、Mg的含量.[结果]苦荞中Mg的含量较高;各元素的回收率为94.8%~101.5%,结果满意.[结论]该法简便、快速、准确,有良好的重现性,能满足日常分析检测的需要.%[Objective] The research aimed to measure the trace element in Tartary buckwheat by the flame atomic absorption spectrometry with microwave digestion. [ Method] Tartary buckwheat sample was carried out the microwave digestion by HNO, + H20,. The flame atomic absorption spectrometry was used to measure the contents of Fe,Cu,Zn,Mn and Mg in the digestion solution of Tartary buckwheat. [Result] Mg content was higher in Tartary buckwheat. The recovery ratio of each element was during 94.8% -101.5% ,and the result was satisfactory.[Conclusion] The method was simple,convenient,quick and accurate. It had the good repeatability and could satisfy the requirement of routine analysis and detection.

  10. A novel methodology for rapid digestion of rare earth element ores and determination by microwave plasma-atomic emission spectrometry and dynamic reaction cell-inductively coupled plasma-mass spectrometry.

    Science.gov (United States)

    Helmeczi, Erick; Wang, Yong; Brindle, Ian D

    2016-11-01

    Short-wavelength infrared radiation has been successfully applied to accelerate the acid digestion of refractory rare-earth ore samples. Determinations were achieved with microwave plasma-atomic emission spectrometry (MP-AES) and dynamic reaction cell - inductively coupled plasma-mass spectrometry (DRC-ICP-MS). The digestion method developed was able to tackle high iron-oxide and silicate matrices using only phosphoric acid in a time frame of only 8min, and did not require perchloric or hydrofluoric acid. Additionally, excellent recoveries and reproducibilities of the rare earth elements, as well as uranium and thorium, were achieved. Digestions of the certified reference materials OREAS-465 and REE-1, with radically different mineralogies, delivered results that mirror those obtained by fusion processes. For the rare-earth CRM OKA-2, whose REE data are provisional, experimental data for the rare-earth elements were generally higher than the provisional values, often exceeding z-values of +2. Determined values for Th and U in this reference material, for which certified values are available, were in excellent agreement. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Determination of cobalt, nickel, iron, niobium, tantalum, vanadium and chrome in tungsten-based hard alloy by microwave digestion-inductively coupled plasma atomic emission spectrometry%微波消解-电感耦合等离子体原子发射光谱法测定钨基硬质合金中钴镍铁铌钽钒铬

    Institute of Scientific and Technical Information of China (English)

    成勇; 彭慧仙; 袁金红; 胡金荣

    2013-01-01

    以硝酸和磷酸(V(HNO3)∶V(H3PO4)=5∶1)作为消解试剂,采取高压密闭微波加热方法对钨钴或钨镍类钨基硬质合金样品进行消解,消解液用水定容后直接以电感耦合等离子体原子发射光谱法(ICP-AES)测定0.005%~10% Co、Ni和0.005%~1% Fe、Nb、Ta、V、Cr、Mo的含量.考察了消解试剂中的硝酸和磷酸量对试样消解的影响以及微波控制参数等最佳消解条件,建立了微波消解-无机试剂络合基体钨的样品消解方法,从而避免了因钨酸沉淀析出而导致部分待测元素损失和使用有机络合剂对光谱测定的干扰影响.实验结果表明:采用以5 min升温至130℃并保持5 min,再以5 min升温至190℃并保持15 min的消解程序,样品的消解效果较好.试验通过优选元素分析谱线,基体匹配和同步背景校正法消除了高钨基体的影响和光谱干扰,确保了方法的可靠性.背景等效浓度值从5 μg/L (Nb)至18 μg/L(Fc),元素检出限从4 μg/L (Nb)至13 μg/L (Fe).方法用于钨基硬质合金样品中上述合金或杂质元素的测定,RSD<3%,加标回收率在97%~104%之间,测定结果与国家标准方法检测结果对照一致.%The tungsten-based hard alloy samples (such as tungsten-cobalt and tungsten-nickel) were digested by high pressure closed microwave heating method using nitric acid-phosphoric acid (V(HNO3) : V(H3PO4)=5 :1) as digestion reagent. After dilution with water, the content of Co, Ni (0.005%-10%), Fe, Nb, Ta, V, Cr and Mo (0. 005%-l%) in digestion solution was directly determined by microwave digestion-inductively coupled plasma atomic emission spectrometry (ICP-AES). The effect of nitric acid and phosphoric acid concentration on sample digestion was investigated. The optimal digestion conditions such as microwave control parameters were studied. The sample digestion method by microwave digestion was established. The matrix tungsten was complexed with inorganic reagents

  12. Evaluation of an ultrasonic acid digestion procedure for total heavy metals determination in environmental and biological samples

    Energy Technology Data Exchange (ETDEWEB)

    Kazi, Tasneem G. [Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan)], E-mail: tgkazi@yahoo.com; Jamali, Mohammad K. [Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan)], E-mail: mkhanjamali@yahoo.com; Arain, Mohammad B. [Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan)], E-mail: bilal_ku2004@yahoo.com; Afridi, Hassan I. [Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan)], E-mail: hassanimranafridi@yahoo.com; Jalbani, Nusrat [Pakistan Council for Scientific and Industrial Research, University Road, Karachi 75280 (Pakistan)], E-mail: nusratjalbani_21@yahoo.com; Sarfraz, Raja A. [Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan)], E-mail: rajaadilsarfraz@gmail.com; Ansari, Rehana [Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan)], E-mail: rehana_ansari_57@yahoo.com

    2009-01-30

    In this study, a sample preparation method based on ultrasonic assisted acid digestion (UAD) has been evaluated for total heavy metals (Cd, Cr, Ni and Pb) determination in different environmental (soil, sediment and sewage sludge), and biological (fish muscles, vegetables and grains) samples, using electrothermal atomic absorption spectrometry (ETAAS). The investigated parameters influencing UAD such as presonication time, sonication time, temperature of ultrasonic bath, and different acid mixtures were fully optimized, whereas power was maintained constant at 100% of nominal power of ultrasonic bath. Six different sets of above parameters were applied on six certified reference materials (CRMs) having different matrices. The accuracy of the method was also tested by comparing the results with those obtained from conventional hot plate assisted acid digestion method on same CRMs. Analytical results for HMs by both methods showed no significant difference at 95% confidence limit (p < 0.05). Recoveries of HMs ranging from 96.2% to 102% and 96.3% to 98.6% were obtained from biological and environmental samples, respectively. The average relative standard deviation of UAD method varied between 3.5% and 8.2%, depending on the analyte.

  13. Competition between bound and free peptides in an ELISA-based procedure that assays peptides derived from protein digests

    Directory of Open Access Journals (Sweden)

    Pace Umberto

    2006-05-01

    Full Text Available Abstract Background We describe an ELISA-based method that can be used to identify and quantitate proteins in biological samples. In this method, peptides in solution, derived from proteolytic digests of the sample, compete with substrate-attached synthetic peptides for antibodies, also in solution, generated against the chosen peptides. The peptides used for the ELISA are chosen on the basis of their being (i products of the proteolytic (e.g. tryptic digestion of the protein to be identified and (ii unique to the target protein, as far as one can know from the published sequences. Results In this paper we describe the competition assay and we define the optimal conditions for the most effective assay. We have performed an analysis of the kinetics of interaction between the four components of the assay: the plastic substratum to which the peptide is bound, the bound peptide itself, the competing added peptide, and the antibody that is specific for the peptide and we compare the results of theoretical simulations to the actual data in some model systems. Conclusion The data suggest that the peptides bind to the plastic substratum in more than one conformation and that, once bound, the peptide displays different affinities for the antibody, depending on how it has bound to the plate

  14. Fate of antibiotic resistance genes and its drivers during anaerobic co-digestion of food waste and sewage sludge based on microwave pretreatment.

    Science.gov (United States)

    Zhang, Junya; Chen, Meixue; Sui, Qianwen; Wang, Rui; Tong, Juan; Wei, Yuansong

    2016-10-01

    In this study, anaerobic digestion of mono-SS, MW-SS:FW and SS:MW-FW was investigated to understand the fate of ARGs and its drivers. Anaerobic digestion was effective for the reduction of metal resistance genes (MRGs), and could reduce the abundance of blaOXA-1, sulI and tetG, while sulII in co-digestion and blaTEM and ereA only in MW-SS. ARGs reduction could be partly attributed to the reduction of co-selective pressure from heavy metals reflected by MRGs. However, the abundance of mefA/E, ermB, ermF, tetM and tetX increased significantly. Anaerobic co-digestion, especially for MW-SS, could reduce total ARGs abundance compared with mono-SS, and evolution of bacterial community was the main driver for the fate of ARGs.

  15. Determination of Chromium in Shellfish Using Microwave Digestion and Graphite Furnace Atomic Absorption Spectrometer with Zeeman Correction%微波消解-塞曼石墨炉原子吸收光谱法检测贝类中的铬

    Institute of Scientific and Technical Information of China (English)

    顾捷; 刘琴; 祝银; 王范盛; 方旭波

    2014-01-01

    In this paper, the method for determining chromium in shellfish is studied using Microwave Digestion and Graphite Furnace Atomic Absorption Spectrometry (GF-AAS) with Zeeman correction. The results of analysis demonstrate that by Microwave Digestion, the samples are digested evenly and completely. When chromium working curve is linear within the range of 0.00~15.00μg·L-1, it is found that chromium concentration can be described by a smooth curve with the correlation coefficient r=1.0000. Based on this working curve, the results of Sinonovacula constricta can be determined. Comparing Tegillarca granosa with Mussel in their recovery rates, it is found that the latter can reach as high as 82%~95%. Moreover, the accuracy and precision of this method are also tested with the national standard substance (Laminaria japonica Aresch and Mussel). It shows that the errors of the results fall within the permissible range. The relative standard deviations were 2.93%and 2.54%. To conclude, with high sensibility, high quality and simple procedure, the Microwave Digestion and Graphite Furnace Atomic Absorption Spectrometry (GF-AAS) equipped with Zeeman correction, is suitable for determination of chromium in shellfish samples.%建立了分析贝类样品中铬含量的微波消解-塞曼石墨炉原子吸收光谱法,并对样品前处理方法和检测条件进行探讨.实验结果表明,利用微波消解进行前处理的样品溶样均匀,样品消解完全.石墨炉铬工作曲线浓度范围设定在0.00~15.00μg·L-1之间时,铬浓度与其吸光值呈良好的曲线关系,得出的新合理一元二次方程相关系数r=1.0000.同时对3种贝类样品进行平行测定和加标回收率测定,平行性好,加标回收率保持在82%~95%.并利用国家标准物质海带和贻贝成份分析标准物质进行质量控制,得到的测定值在标准证书的允许误差范围内,相对标准偏差分别为2.93%和2.54%.表明该方法具有操作简

  16. Determination of lead in tea leaf by Microwave digestion HG -AFS%微波消解-氢化物发生原子荧光光谱法测茶叶中铅

    Institute of Scientific and Technical Information of China (English)

    韩英

    2012-01-01

    Objective: To determine lead level in tea leaf by microwave digestion - Hydride generation atomic fluorescence spectrometry. Methods: The test samples were treated with microwave digestion. Then under hydro-chloric acid medium, hydride was generated by reaction of digested samples and potassium borohydride to get atomic lead. Results: The samples were digested completely. The recovery of the method was 88% ~ 107% , the detection limits of the instrument and the method were 0. 29 μg/L and 0. 15 μg/L respectively, the linear range was 0 μg/L -50 μg/L (r >0. 999) , and the RSD was 0. 97% ~3.6% . Conclusion: The method had the advantages of sim-pleness, stability, harmlessness, high sensitivity and low detection limit, without tall order for instruments and staff, only a single - channel or dual - channel atomic fluorescence spectrometer was available.%目的:建立茶叶中铅含量的微波消解-氢化物发生原子荧光光谱法.方法:试样采用微波消解技术消解,研究了在盐酸介质下与硼氢化钾生成氢化物在电热原子化器中产生荧光光谱的行为,并对各种分析条件进行优化和探讨.结果:样品消解完全彻底,加铅标准10μg/L,回收率88%~107%,仪器检出限为0.29 μg/L,方法检出限为0.15μg/g,线性范围为0μg/L~ 50 μg/L,r>0.999,RSD为0.97%~3.6%.结论:本法简便、稳定、危害小、灵敏度高、检出限低,对仪器、人员均无过高要求,只需一台单道或双道原子荧光光度计即可.

  17. Simultaneous determination of Se, trace elements and major elements in Se-rich rice by dynamic reaction cell inductively coupled plasma mass spectrometry (DRC-ICP-MS) after microwave digestion.

    Science.gov (United States)

    Wei, Yi Hua; Zhang, Jin Yan; Zhang, Da Wen; Luo, Lin Guang; Tu, Tian Hua

    2014-09-15

    A quick and accurate method was devised to determine Se, As, Ba, Ca, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sr and Zn in Se-rich rice samples by microwave digestion and inductively coupled plasma-mass spectrometry (ICP-MS). Spectral interferences on Se were eliminated using methane as a reaction gas in the dynamic reaction cell (DRC). Rhodium was used as an internal standard to compensate for sample matrix effects. A rice-certified reference material (CRM) (GBW 10010) was used to verify the accuracy of the method. The method detection limits were 0.001-0.03 mg/kg, analyte recoveries were 85-108% and precisions (RSDs) ranged from 2.1% to 5.8%. Correlation analysis showed that the Se concentrations in the Se-rich rice samples correlated well with the Cu concentrations (r=0.53, p<0.05).

  18. Determination of Beryllium in Soil and Sediment by GFAAS with Microwave Digestion%微波消解石墨炉原子吸收法测定土壤和沉积物中的铍

    Institute of Scientific and Technical Information of China (English)

    任兰; 杨正标

    2012-01-01

    Beryllium concentrations in soils and sediments were determined by GFAAS with microwave digestion using palladium chloride as matrix modifier.Conditions of microwave digestion were optimized to remove coexisting element interference in the determination.Calibration curves of the method exhibited linearity in a range between 0 μg/L and 4.00 μg/L.Detection limit was 0.01 μg/g ( sample quality 0.200 0 g,sample solution volume 50 mL) .The RSD of duplicated samples ranged from 3.5% to 6.7% .Spiked recoveries of samples ranged from 84.0% to 113%.%以氯化钯为基体改进剂,采用微波消解石墨炉原子吸收法测定土壤和沉积物中的铍,优化了微波消解条件,考察了共存元素对测定的干扰.方法在0 μg/L~4.00 μg/L范围内线性良好,检出限为0.01μg/g(以取样质量0.2000 g、定容体积50 mL计),标准样品平行测定的RSD为3.5%~6.7%,实际样品的加标回收率为84.0%~ 113%.

  19. [ENDOSCOPIC RETROGRADE CHOLANGIO PANCREATOGRAPHY(ERCP): EXPERIENCE IN 902 PROCEDURES AT THE ENDOSCOPY DIGESTIVE CENTRE OF "ARZOBISPO LOAYZA" HOSPITAL

    Science.gov (United States)

    Vargas Cardenas, Gloria; Astete Benavides, Magdalena

    1997-01-01

    On 1997, the Digestive Endoscopy Centre of "Arzobispo Loayza" Hospital was created with the cooperation of JICA (Japan International Cooperation Agency). 902 ERCP were regularly performed from 1985 to August 1997. 902 tests were reviewed and 831 cases were left after excluding 16 ampulloma cases, 15 cannulated or insufficient cases and 40 cases dealing only with pancreatic duct cannulation. The population is examined according to sex, age and diagnosis, establishing a relation among these three variables. Results showed that most of ERCP were made to women (3:1) with Choledocal Lithiasis (C.L.) and cholecistectomy antecedents, a greater frequency was observed in 56-65 year old women. In males, it was more frequent in people older than 65 years, they also had predominance of choledocal lithiasis, but malignant neoplasia of the biliary duct ranked in the third place. The highest incidence of C.L. with cholecistectomy antecedents suggests the performance of an appropriate evaluation of the biliary duct before surgery.

  20. Determination of Cobalt in Soil by Microwave Digestion and Graphite Furnace Atomic Absorption%微波消解-石墨炉原子吸收法测定土壤中钴

    Institute of Scientific and Technical Information of China (English)

    刁小冬

    2014-01-01

    Microwave digestion and graphite furnace atomic absorption were applied to test cobalt in soil.The soil sample with palladium nitrate as matrix modifier was treated by microwave.The standard soil sample was used.The results showed that the accuracy and precision of the method can reach the quality control standard.The method al-so can meet the environmental monitoring requirements since its recovery rate has achieved 94.4%~104.8%.%以硝酸钯为基体改进剂,采用微波消解土壤样品,石墨炉原子吸收法测定土壤中钴。对标准土样的测定结果表明,方法的准确度和精密度符合分析测试质量控制要求,方法的加标回收率为94.4%~104.8%,能够满足环境监测分析的要求。

  1. Simultaneous Determination of 13 Elementals in Aquatic Products by Microwave Digestion-ICP/MS%微波消解-ICP/MS法同时测定水产品中13种元素

    Institute of Scientific and Technical Information of China (English)

    袁静; 王亚林; 汤洁

    2013-01-01

    A method was developed to simultaneously determine 13 elementals by microwave digestion -ICP/MS in aquatic products with Cesium and Indium as internal standards .HNO3 -H2 O2 was used to digest the samples.The method detection limits of the 13 elementals ranged from 0.05 ng/g to 0.064 μg/g and the RSDs of 4 parallel determination were less than 5%. The spiked recoveries of silver carp were between 81%and 117%.%用硝酸-双氧水体系微波消解,以In、Sc为内标,采用电感耦合等离子体质谱法( ICP/MS)同时测定水产品中V、Cr、Co、Ni、Cu、Zn、As、Se、Cd、Sb、Ba、Tl、Pb等13种元素。各元素的检出限在0.05 ng/g~0.064μg/g之间,样品平行测定4次的RSD<5%,鲢鱼样品的加标回收率在81%~117%之间。

  2. Application of laparoscopy in the combined surgical procedures of gynecological and digestive disorders in obese women: a retrospective cohort study.

    Science.gov (United States)

    Wang, Haibo; Zhou, Ailing; Fan, Min; Li, Ping; Qi, Shengwei; Gao, Licai; Li, Xiujuan; Zhao, Jinrong

    2015-04-01

    Laparoscopy surgery has been widely used for many decades and combined laparoscopic procedures have become favorable choices for concomitant pathologies in the abdomen. However, the type of combination procedures and their safety in obese women have not been well elucidated in obese women. Here we retrospectively reported 147 obese women underwent combined laparoscopic gynecological surgery and cholecystectomy/appendicectomy in our hospital from January 2003 to December 2011. Of the total number of patients (n = 147), various laparoscopic gynecological surgeries were combined with laparoscopic cholecystectomy in 93 patients, and were combined with laparoscopic appendectomy in the rest 54 patients. Patients' ages ranged from 24 to 55 years with an average of 33 years. Our results showed that combined procedures caused various operative time and blood loss, with no difference considering the time to resume oral intake and length of hospital stay. Intraoperative complications occurred in a total of 7 patients (4.8%). None of the patients suffered from major complications after laparoscopic surgery, and minor postoperative complications occurred in 30 patients (20.4%). The follow-up period ranged from 6 to 24 months (average, 18.5 months). None of the patients developed complications during follow-up, except that one patient suffered from colporrhagia. Our results further suggest that the combined abdominal laparoscopic procedures of gynecologic and general surgery are safe and economic choices for obese women, and benefit patients in many ways including lesser pain, shorter hospital stays and earlier recovery. Copyright © 2015 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

  3. Determination of Five Heavy Metals (Cu, Pb, As, Cd, Hg) in Folium Microcotis by Microwave Digestion with Inductively Coupled Plasma Mass Spectrometry%微波消解/ICP-MS法测定布渣叶中5种重金属的含量

    Institute of Scientific and Technical Information of China (English)

    卢鹏; 陈浩桉; 隆颖; 杨立伟; 叶文才; 江仁望

    2011-01-01

    Objective To assay the contents of 5 heavy metals of copper(Cu) , arsenic 1 (As) , cadmium(Cd), hydrargyrum (Hg), plumbum (Pb) in Folium Microcotis by microwave digestion with inductively coupled plasma mass spectrometry(ICP-MS). Methods With germanium(72Ge) , indium(115In) and bismuth(209Bi) as the internal standard substance, the contents of the 5 heavy metals of Cu, Pb, Hg, As and Cd were detected with ICP-MS simultaneously after the samples of Folium Microcotis was treated by microwave digestion. The national standard substance of orange leaves(GBW10020) was used to estimate the accuracy of method. Results For all of the analyzed heavy metals, the correlation coefficient of the calibration curves was over 0.9990, RSD were in the range of 1.1 %~11.6 %, and the recovery rates of the procedure were 97.9 %~108.9 %. Conclusion This method is accurate, convenient, and rapid with high sensitivity, and can be applied to assay the five heavy metals of Cu, Cd, Hg, Pb, As in Folium Microcotis.%目的 采用微波消解电感耦合等离子体质谱(ICP- MS)法测定布渣叶药材中铜(Cu)、铅(Pb)、汞(Hg)、砷(As)、镉(Cd)五种重金属的含量.方法布渣叶经微波消解后,以锗(72Ge)、铟(115In)、铋(209Bi)作为内标物质,用ICP- MS法同时测定样品中Cu、Pb、Hg、As、Cd五种重金属元素的含量.用国家一级标准物质柑橘叶(GBW 10020)评价方法的准确性.结果对于所测元素,校准曲线相关系数r>0.9990回收率为97.9%~108.9%,RSD值在1.1%~11.6%.结论该方法简便、快速、灵敏度高,适合于布渣叶中五种重金属的含量测定.

  4. Analytical Quality Control of Determination of Lead in Urine by Microwave Digestion and Inductively Coupled Plasma Mass Spectrometry%微波消解-电感耦合等离子体质谱法测定尿中铅的分析质量控制

    Institute of Scientific and Technical Information of China (English)

    殷忠

    2012-01-01

    [Objective]To implement analytical quality control and predict analysis error of lead determination in urine by microwave digestion and inductively coupled plasma mass spectrometry (ICP-MS), so as to investigate the laboratory lead testing and quality control capability, and to enhance the accuracy and comparability of laboratory testing results. [ Methods ] According to the water laboratory analytical quality control (AQC/WATER) procedure for precision and accuracy of trace elements, the analysis was processed. [ Results ] Total standard deviation of every solution was less than 5% (W) of the concentration, and confidence limit of total average rate of recovery (R/d=1.03) was in allowable range. The testing result of the blind samples was satisfactory. [ Conclusion ] The laboratory analysis error of lead determination in urine by microwave digestion and ICP-MS can be controlled in the permitted range.%[目的]通过对微波消解的电感耦合等离子体质谱法测定尿中铅,实施分析质量控制和进行分析误差预测,了解实验室铅检测能力和质量控制能力,提高实验室检测结果的准确性和可比性. [方法]按水质分析评价微量元素精密度和准确度中的实验室内部质量控制工作程序进行. [结果]各种溶液测定的总标准差(S1)均小于其浓度的5%,总平均回收率可信限(R/d=1.03)在允许范围内,质控考核结果为满意. [结论]用微波消解的电感耦合等离子体质谱法测定尿中铅,实验室分析误差可控制在容许值内.

  5. Virtual reality, augmented reality, and robotics applied to digestive operative procedures: from in vivo animal preclinical studies to clinical use

    Science.gov (United States)

    Soler, Luc; Marescaux, Jacques

    2006-04-01

    Technological innovations of the 20 th century provided medicine and surgery with new tools, among which virtual reality and robotics belong to the most revolutionary ones. Our work aims at setting up new techniques for detection, 3D delineation and 4D time follow-up of small abdominal lesions from standard mecial images (CT scsan, MRI). It also aims at developing innovative systems making tumor resection or treatment easier with the use of augmented reality and robotized systems, increasing gesture precision. It also permits a realtime great distance connection between practitioners so they can share a same 3D reconstructed patient and interact on a same patient, virtually before the intervention and for real during the surgical procedure thanks to a telesurgical robot. In preclinical studies, our first results obtained from a micro-CT scanner show that these technologies provide an efficient and precise 3D modeling of anatomical and pathological structures of rats and mice. In clinical studies, our first results show the possibility to improve the therapeutic choice thanks to a better detection and and representation of the patient before performing the surgical gesture. They also show the efficiency of augmented reality that provides virtual transparency of the patient in real time during the operative procedure. In the near future, through the exploitation of these systems, surgeons will program and check on the virtual patient clone an optimal procedure without errors, which will be replayed on the real patient by the robot under surgeon control. This medical dream is today about to become reality.

  6. Determination of Metal Elements in Different Parts of Papaya by Flame Atomic Absorption Spectrometry with Microwave Digestion%微波消解-FAAS测定番木瓜不同部位的金属元素含量

    Institute of Scientific and Technical Information of China (English)

    袁竹连

    2013-01-01

    In order to explore the contents of metal elements in the papaya pulp,peel and seed, flame atomic absorption spectrometry (FAAS) method was used for determination of K,Na,Ca, Mg,Cu,Fe and Zn in the three parts of papaya. In addition, the digesting conditions were optimized. The results showed that under the optimized microwave digestion conditions and FAAS method, the samples were digested quickly and completely, there was a good linear relation between the concentration of the metal element standards and the absorbance value,the correlation coefficient was 0. 995 7 — 0. 999 9, the detection limit was 0. 002 — 0. 131, the recovery rate was 98. 30% —101. 67% and RSD was 0. 20%-4. 12%(n = 6). So microwave digestion-FAAS was a fast good detection method with complete digestion,less interference and stable measurement results. There were more K,Ca,Mg and less Cu,Fe,Zn in the three parts of papaya; there were more K,Mg,Cu,Zn,Fe in papaya peel and seed than in pulp,so papaya peel and seed had more advantage of development in food and medicine.%为探讨番木瓜果肉、果皮、瓜籽中金属元素的含量,采用微波消解-FAAS法测定了番木瓜3个部位的K、Na、Ca、Mg、Cu、Fe、Zn共7种金属元素的含量,并对微波消解条件进行了优化.结果显示,在优化的微波消解条件下,样品消解完全、速度快、效果好,FAAS测定的各金属元素质量浓度与吸光度均呈良好的线性关系,相关系数r为0.995 7~0.999 9,检出限为0.002~0.131,回收率为98.30%~101.67%,RSD为0.20%~4.12%(n=6),说明测定方法可靠,结果稳定;番木瓜3个部位均含有较高的K、Ca、Mg,但Cu、Fe、Zn含量均较低,与番木瓜果肉相比,番木瓜果皮和瓜籽中K、Mg、Cu、Zn、Fe含量较高,食品和药品开发优势更突出.

  7. 微波消解-火焰原子吸收光谱法测定食品中痕量镍%Determination of Trace Nickel in Foods by Microwave Digestion Followed by FAAS

    Institute of Scientific and Technical Information of China (English)

    赵丽杰; 赵丽萍; 李良; 杨旭鹏; 陈宏; 刘永宏

    2012-01-01

    A microwave digestion-flame atomic absorbance spectrometry (FAAS) method was developed to determine trace nickel in foods. The optimal microwave digestion conditions were established as follow: concentrated nitric acid-hydrogen peroxide (4:1, V/V) as digestion solution, digestion time 15 min, and digestion pressure 1.5 MPa. Meanwhile, the optimal solvent medium, activator and instrumental conditions were determined. When present in pH 4.7 acetic acid-sodium acetate buffer, activated by NP-10, the relationship between absorbance and nickel concentration over the range of 3.1 ×10.6 4.8×10-4 g/L as detected under optimized instrumental conditions obeyed Beer's law. The detection wavelength was set at 232.6 nm. The limit of detection of this method was 3.1×10-6 g/L. The maximum precision RSD for 5 replicate determinations of nickel in cereal grains was 4.2% and average spike recoveries ranged from 95.1% to 106.4%. Compared with the method of GB/T 5009.138-2003, the maximum relative error was not higher than 5.8%.%建立微波消解-火焰原子吸收光谱法测定食品中痕量镍的新方法。通过微波消解条件优化,确定最佳消解条件为浓硝酸.双氧水(4:1,V/V)为消解液,1.5MPa消解15min。通过实验介质、活化剂、仪器操作条件的考察,确定最佳分析条件。在pH4.7的醋酸.醋酸钠介质中及NP-10活化下,在仪器的最佳操作条件下,镍在3.1×10-6~4.8×10-4g/L范围内,吸光度与镍质量浓度遵循比尔定律。该方法的测定波长为232.6nm,检出限为3.1×10-6g/L。所建方法用于食品中痕量镍的测定,最大相对标准偏差为4.2%,加标回收率为95.1%~106.4%,所建方法与GB/T5009.138-2003《食品中镍的测定》进行对比,方法相对误差不高于5.8%。

  8. [A new concept in surgery of the digestive tract: surgical procedure assisted by computer, from virtual reality to telemanipulation].

    Science.gov (United States)

    Marescaux, J; Clément, J M; Vix, M; Russier, Y; Tassetti, V; Mutter, D; Cotin, S; Ayache, N

    1998-02-01

    Surgical simulation increasingly appears to be an essential aspect of tomorrow's surgery. The development of a hepatic surgery simulator is an advanced concept calling for a new writing system which will transform the medical world: virtual reality. Virtual reality extends the perception of our five senses by representing more than the real state of things by the means of computer sciences and robotics. It consists of three concepts: immersion, navigation and interaction. Three reasons have led us to develop this simulator: the first is to provide the surgeon with a comprehensive visualisation of the organ. The second reasons is to allow for planning and surgical simulation that could be compared with the detailed flight-plan for a commercial jet pilot. The third lies in the fact that virtual reality is an integrated part of the concept of computer assisted surgical procedure. The project consists of a sophisticated simulator which must include five requirements: a) visual fidelity, b) interactivity, c) physical properties, d) physiological properties, e) sensory input and output. In this report we describe how to obtain a realistic 3D model of the liver from bi-dimensional 2D medical images for anatomical and surgical training. The introduction of a tumor and the consequent planning and virtual resection is also described, as are force feedback and real-time interaction.

  9. Preparation of regenerated immobilized enzyme reactor and application in microwave assisted digestion%磁性可再生性固定化酶制备及其在微波辅助蛋白酶解中的应用

    Institute of Scientific and Technical Information of China (English)

    韦美苹; 庞玉凤; 陈正毅; 苏日辉; 杜甫佑; 阮贵华

    2014-01-01

    将磁性可再生性固定化酶应用于微波辅助蛋白酶解。包覆了 SiO2的 Fe3 O4磁性粒子(Fe3 O4@mSiO2)表面经3-(2,3-环氧丙氧)丙基三甲氧基硅烷偶联剂(GLYMO)与亚氨基二乙酸(IDA)反应的产物(GLYMO-IDA)修饰,加入Cu2+形成金属螯合配体后利用Cu2+与木瓜蛋白酶作用固定木瓜蛋白酶。在优化条件下,获得的固定化酶酶活为1158.8 U,酶活保留率达44.1%。所获得的固定化木瓜蛋白酶具有易再生、再生后酶活稳定的特点。再生5次后酶活平均值为1014 U,再生率达88%。HPLC分析表明,微波辅助结合固定化可再生酶可用于黑蚂蚁蛋白的快速酶解,获得的色谱图轮廓与自由酶酶解结果相似。酶解过程快,多肽丰富且易与底物分离,表明可再生固定化酶结合微波辅助有助于蛋白的酶解与多肽的制备。%The magnetic regenerated immobilized papain is applied for microwave assisted enzymatic digestion (MAED).Fe3O4 magnetic nanoparticles were coated with SiO2by sol-gel method and Fe3O4@ mSiO2 were formed and then modified by the reaction products of 3-Glycidyloxy propyl trimethoxy silane coupling agent (GLYMO)and iminodiacetic acid (IDA).After Cu2+was chelated on the Fe3 O4@mSiO2-GLYMO-IDA,the papain was immobilized on.In optimized conditions,the activity of the immobilized papain was 1 158.8 U and the rate of remained activity of papain was 44.1%.After five times of regeneration,the average activity of the immobilized papain was 1 014 U and regeneration rate was about 88%.Coupled with MAED,the immobilized papain was applied for black ants protein digestion.The HPLC analysis shows that during 30 min,the digestion product from immobilized papain MAED could be easily separated from the substrate and its responding HPLC profiles were similar to the product from free papain digestion,reflecting that the digestion speed of black ants protein with immobilized papain was fast and

  10. Determination of Aluminum Content in Flour Food by Microwave Digestion Spectrophotometry%微波消解-分光光度法测定米面食品中的铝含量

    Institute of Scientific and Technical Information of China (English)

    陈建津; 陈嘉敏; 张志强

    2016-01-01

    Objective: To investigate the harmful substances in foods determination of aluminium, construction and application of spectrophotometry. Methods: The chrome azurol S as chromogenic agent, construct the microwave digestion for sample pretreatment, on the color of the best reaction condition clearly; and rice lfour, dough and bread as test samples for verification of precision and accuracy. Results: Wavelength range 620 nm, acetic acid sodium acetate buffer 8 mL signiifcantly color time 20 min for the best experimental conditions;standard curve was linear over the range, r = 0.998 5. Rice lfour, dough and bread in the aluminum content of RSD respectively 2.5%, 1.3% and 3.4%, the recovery of standard addition of aluminum content rate between 90.5%- 102.0%. Conclusion: With high sensitivity and reproducibility by microwave digestion spectrophotometry, is can be used for the determination of aluminum in lfour food.%目的:探讨米面食品有害物质铝测定中,分光光度法的构建及应用效果。方法:采用铬天青S作为显色剂,构建微波消解对样品进行前处理,对显色反应最佳条件进行明确;并取米粉、油条和馒头作为试验样品,进行精确度和准确度验证。结果:波长范围为620 nm,乙酸乙酸钠缓冲液8 mL,显色时间20 min为最佳实验条件;标准曲线线性范围为0.5~6μg,r=0.9985;米粉、油条和馒头中铝含量RSD分别为2.5%、1.3%、3.4%;铝含量的加标回收率为90.5%~102.0%。结论:微波消解-分光光度法具有较高灵敏性和重现性,是可用于米面食品中铝的测定。

  11. Determination of Arsenic in Matricaria chamomilla L.by microwave digestion-atomic fluorescence spectrometry%微波消解-原子荧光光谱法测定洋甘菊中砷的含量

    Institute of Scientific and Technical Information of China (English)

    辛禄德; 李强; 王建玲; 劳斐; 田树革

    2014-01-01

    Objective To develop an atomic fluorescence spectrometric method for the determination of Ar-senic in Matricaria chamomilla L.Methods Sample was digested with microwave digestion system.The Arsenic was directly analyzed by atomic fluorescence spectrometry,and the methodology of the study was investigated.Results The content of arsenic within the range of 0-10.0 μg/L the correlative coefficient of the calibration curves was over 0.999 3,the average recovery was 100.81% with RSD of 2.59% (n =6). Conclusion The method is convenient,stable,less harmful and highly sensitive.%目的:建立洋甘菊中砷含量的原子荧光光谱检测方法。方法采用微波消解样品,通过原子荧光光谱法测定洋甘菊中砷含量,并进行了方法学考察。结果砷在0~10.0μg/L (r =0.9993)范围内峰面积与浓度呈良好线性关系,平均加样回收率为100.81%,RSD=2.59%(n =6)。结论该测量方法简便、稳定、危害小、灵敏度高。

  12. 2013年云南省市售乳及乳制品中铬测定方法的改进及结果分析%Determination of chromium in milk and dairy products by microwave digestion-graphite furnace atomic absorption in 2013

    Institute of Scientific and Technical Information of China (English)

    梁孟军; 祁立辉; 王秋波

    2015-01-01

    Objective To establish a detecting method for the determination of chromium in milk and dairy products by microwave digestion-graphite furnace atomic absorption.MethodUsing dry digestion methods and microwave digestion to process sample detected by graphite furnace atomic absorption and compared two treatment methods for recovery.ResultThe precision of this method is 2.17%;the repeatability is 4.58% for dry digestion and 4.35% for microwave digestion r;the recovery of dry digestion was 70.35% ~89.08%,an average of 81.78%;the recovery of microwave digestion was 85.96%~101.43%,an average of 94.35%.And the con-tents of chromium in milk and dairy products of 273 samples were measured by this method. Conclusionthe method is fast,accurate, reproducible,high recovery rate,low acid consumption and safety,and it is the preferred method for detection of chromium in milk and dairy products.%目的:改进乳及乳制品中铬的微波消解-石墨炉原子吸收分析方法。方法:采用干法消解和微波消解法对样品进行消解处理,采用石墨炉原子吸收法进行检测分析,比较两种处理方法的回收率。结果:方法的精密度为2.17%,重复性干法为4.58%,微波消解的为4.35%;干法消解回收率为70.35%~89.08%,平均81.78%;微波消解的回收率为85.96%~101.43%,平均94.35%。并用建立的方法检测273件市售乳及乳制品中铬的含量。结论:方法具有快速、精密度高、重复性好、回收率高、酸消耗少、安全等特点,是检测乳及乳制品中铬的首选方法。

  13. Matrix-assisted laser desorption-ionization mass spectrometry peptide mass fingerprinting for proteome analysis: identification efficiency after on-blot or in-gel digestion with and without desalting procedures.

    Science.gov (United States)

    Lamer, S; Jungblut, P R

    2001-03-10

    In theory, peptide mass fingerprinting by matrix assisted laser desorption-ionization mass spectrometry (MALDI-MS) has the potential to identify all of the proteins detected by silver staining on gels. In practice, if the genome of the organism investigated is completely sequenced, using current techniques, all proteins stained by Coomassie Brilliant Blue can be identified. This loss of identification sensitivity of ten to hundred-fold is caused by loss of peptides by surface contacts. Therefore, we performed digestion and transfer of peptides in the lower microl range and reduced the number of steps. The peptide mix obtained from in-gel or on-blot digestion was analyzed directly after digestion or after concentration on POROS R2 beads. Eight protein spots of a 2-DE gel from Mycobacterium bovis BCG were identified using these four preparation procedures for MALDI-MS. Overall, on-blot digestion was as effective as in-gel digestion. Whereas higher signal intensities resulted after concentration, hydrophilic peptides are better detected by direct measurement of the peptide mix without POROS R2 concentration.

  14. Influence of chemical and mineralogical properties of organic amendments on the selection of an adequate analytical procedure for trace elements determination.

    Science.gov (United States)

    García-Delgado, C; Cala, V; Eymar, E

    2012-01-15

    Six digestion procedures were tested to improve extraction methods for determination of trace elements in various organic amendments with high inorganic fractions. These procedures were tested in terms of pH, CaCO(3), organic matter, elemental analysis, BCR sequential extraction and X-ray diffraction analysis. Aqua regia extraction (ISO 11466), total digestion HF-HNO(3)-HClO(4) and four microwave-assisted digestions (i.e., HNO(3), HCl-HNO(3), HNO(3)-HF and HCl-HNO(3)-HF) were used. The effect of acid mixtures on microwave-assisted digestion of mineral fractions was assessed by Si and Al analysis and X-ray diffraction in the solid residues obtained. Microwave HF acid mixtures obtained highest trace element recoveries for all tested metals except Al. CaF(2) and CaAlF(5) precipitates were also detected using X-ray diffraction in the residues after microwave digestions with HF acid mixtures of amendments with high calcium content. A decision flowchart was suggested to determine the best acid mixture according to the amendment and the metals to be analyzed.

  15. Microwave power coupler for a superconducting multiple-cell cavity for accelerator application and its testing procedures

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jianjian [Illinois Inst. of Technology, Chicago, IL (United States)

    2008-12-01

    Superconducting cavity resonators offer the advantage of high field intensity for a given input power, making them an attractive contender for particle accelerator applications. Power coupling into a superconducting cavity employed in a particle accelerator requires unique provisions to maintain high vacuum and cryogenic temperature on the cavity side, while operating with ambient conditions on the source side. Components introduced to fulfill mechanical requirements must show negligible obstruction of the propagation of the microwave with absence of critical locations that may give rise to electron multipaction, leading to a multiple section design, instead of an aperture, a probe, or a loop structure as found in conventional cavities. A coaxial power coupler for a superconducting multiple-cell cavity at 3.9 GHz has been developed. The cavity is intended to be employed as an accelerator to provide enhanced electron beam quality in a free-electron laser in Hamburg (FLASH) user facility. The design of the coupler called for two windows to sustain high vacuum in the cavity and two bellows to accommodate mechanical dimensional changes resulting from cryogenics. Suppression of multipacting was accomplished by the choice of conductor dimensions and materials with low second yield coefficients. Prior to integration with the cavity, the coupler was tested for intrinsic properties in a back-to-back configuration and conditioned for high-power operation with increasing power input. Maximum incident power was measured to be 61 kW. When integrated with the superconducting cavity, a loaded quality factor of 9 x 10 5 was measured by transient method. Coupler return loss and insertion loss were estimated to be around -21 dB and -0.2 dB, respectively.

  16. Below and above boiling point comparison of microwave irradiation and conductive heating for municipal sludge digestion under identical heating/cooling profiles.

    Science.gov (United States)

    Hosseini Koupaie, E; Eskicioglu, C

    2015-01-01

    This research provides a comprehensive comparison between microwave (MW) and conductive heating (CH) sludge pretreatments under identical heating/cooling profiles at below and above boiling point temperatures. Previous comparison studies were constrained to an uncontrolled or a single heating rate due to lack of a CH equipment simulating MW under identical thermal profiles. In this research, a novel custom-built pressure-sealed vessel which could simulate MW pretreatment under identical heating/cooling profiles was used for CH pretreatment. No statistically significant difference was proven between MW and CH pretreatments in terms of sludge solubilization, anaerobic biogas yield and organics biodegradation rate (p-value>0.05), while statistically significant effects of temperature and heating rate were observed (p-valueheating/cooling rates) was controlled.

  17. 微波消解/AAS法测定分子筛中的镍含量%Determination of nickel in molecular sieve catalyst by microwave digestion-atomic absorption spectrometry

    Institute of Scientific and Technical Information of China (English)

    陈震; 贾隽涵; 王宸宸; 王永娟; 易玉峰; 丁福臣

    2016-01-01

    分子筛催化剂以及含有金属钨的催化剂在一般的微波消解体系下难以被消解。探索了以浓HCl、浓HCl+H2 O2、浓HNO3+H2 O2、王水、浓H2 SO4+H2 O2、浓H2 SO4+浓HNO3、浓H3 PO4为消解体系,消解含金属钨的分子筛催化剂。找到了一种能在短时间内既能消解分子筛催化剂又可以消解含金属钨的浓H3 PO4消解体系。并通过原子吸收光谱法和分光光度法对催化剂中的镍含量进行了测量。该方法样品用量少、省时、省酸、操作简单、环境污染小。%Molecular sieve catalysts and catalysts containing tungsten are difficult to be dissolved by mi -crowave in routine acidic digestion system .Acidic digestion system of concentrated hydrochloric acid ,con-centrated hydrochloric acid and hydrogen peroxide mixture ,concentrated nitric acid and hydrogen perox-ide mixture,nitrohydrochloric acid,concentrated sulphuric acid and hydrogen peroxide mixture ,concen-trated sulphuric acid and concentrated nitric acid mixture ,concentrated phosphoric acid were used to dis-solve molecular sieve catalysts containing tungsten by microwave .Concentrated phosphoric acid was found to be the suitable digestion system to dissolve the molecular sieve catalyst containing tungsten in a short period of time .The nickel content in the catalyst was measured by atomic absorption spectrometry and spectrophotometry.The method has the advantage of less sample needed ,high-speed,less acid needed, simplicity of operation and little of environmental pollution .

  18. Development of sample preparation method for auxin analysis in plants by vacuum microwave-assisted extraction combined with molecularly imprinted clean-up procedure.

    Science.gov (United States)

    Hu, Yuling; Li, Yuanwen; Zhang, Yi; Li, Gongke; Chen, Yueqin

    2011-04-01

    A novel sample preparation method for auxin analysis in plant samples was developed by vacuum microwave-assisted extraction (VMAE) followed by molecularly imprinted clean-up procedure. The method was based on two steps. In the first one, conventional solvent extraction was replaced by VMAE for extraction of auxins from plant tissues. This step provided efficient extraction of 3-indole acetic acid (IAA) from plant with dramatically decreased extraction time, furthermore prevented auxins from degradation by creating a reduced oxygen environment under vacuum condition. In the second step, the raw extract of VMAE was further subjected to a clean-up procedure by magnetic molecularly imprinted polymer (MIP) beads. Owing to the high molecular recognition ability of the magnetic MIP beads for IAA and 3-indole-butyric acid (IBA), the two target auxins in plants can be selectively enriched and the interfering substance can be eliminated by dealing with a magnetic separation procedure. Both the VMAE and the molecularly imprinted clean-up conditions were investigated. The proposed sample preparation method was coupled with high-performance liquid chromatogram and fluorescence detection for determination of IAA and IBA in peas and rice. The detection limits obtained for IAA and IBA were 0.47 and 1.6 ng/mL and the relative standard deviation were 2.3% and 2.1%, respectively. The IAA contents in pea seeds, pea embryo, pea roots and rice seeds were determined. The recoveries were ranged from 70.0% to 85.6%. The proposed method was also applied to investigate the developmental profiles of IAA concentration in pea seeds and rice seeds during seed germination.

  19. 微波消解 ICP-OES/ICP-MS测定鳄梨中微量元素%Determination of Trace Elements in Avocado by ICP-OES and ICP-MS with Microwave Digestion

    Institute of Scientific and Technical Information of China (English)

    陈嘉勋; 陈建平; 钟宇强; 张飞; 梁洁怡; 舒永红

    2015-01-01

    A method for determination of trace elements in avocado was reported first time.22 elements such as boron were determined by ICP-OES and ICP-MS with microwave digestion and HNO 3-H2 O2 mixed acid.This method was simple and rapid for use.The RSDs ( n=7 ) for every element were all less than 5% and recoveries were among 90%~110%.The analytical results for Certified Reference Material ( GBW 10047 ) were approving.%首次报道了鳄梨中微量元素的含量分析方法。采用HNO3-H2 O2混合酸,经微波消解进行样品前处理,电感耦合等离子体光谱( ICP-OES)和电感耦合等离子体质谱法( ICP-MS)测定其中B等22种微量元素。该方法简便、快速,各元素测定的相对标准偏差小于5%(RSD, n=7),样品加标回收率在90%~110%之间,用于国家一级标准物质胡萝卜(GBW10047)分析,结果满意。

  20. Determination of free amino acids and 18 elements in freeze-dried strawberry and blueberry fruit using an Amino Acid Analyzer and ICP-MS with micro-wave digestion.

    Science.gov (United States)

    Zhang, Hua; Wang, Zhen-Yu; Yang, Xin; Zhao, Hai-Tian; Zhang, Ying-Chun; Dong, Ai-Jun; Jing, Jing; Wang, Jing

    2014-03-15

    The objective of this study was to investigate the level of 18 trace elements of two freeze-dried samples from the Blueberry (Vaccinium corymbosum) and the Strawberry (Fragaria × Ananassa). The total free amino acid composition in the blueberry and strawberry was determined by an Amino Acid Analyzer. Eleven free amino acids were found in both berries. The trace elements in each dried fruit sample were determined by ICP-MS with microwave digestion. The linearity range of the standard curves was 0-1250.0 μg L(-1) (Mg, P, K, Ca),while in all cases, except for B, Na, Al, Cr, Mn, Fe, Ni, Cu, Zn, Se, Cd, Pb, Ge and As, which was 125.0 μg mL(-1), all related coefficients were above 0.9999; recovery was in the range of 79.0-106.8%. Minor concentrations of nutritional elements were found in each freeze-dried berry. In sum, the toxic trace element analysis found the content of toxic trace elements in each freeze-dried berry sample was safe for human consumption and that the overall quality of the blueberry surpassed that of the strawberry. The results certify that the two freeze-dried berries have potential for human consumption in value-added products and have a certain theoretical and practical significance.

  1. 微波消解塞曼石墨炉原子吸收法测定大米中微量镍%A Determination of Trace Nickel in Rice by Microwave Digestion And Graphite Furnace AtomicAbsorption Spectrometry

    Institute of Scientific and Technical Information of China (English)

    袁友明; 姚晶晶; 路磊; 陶宁丽

    2014-01-01

    利用微波消解技术处理样品,用塞曼石墨炉原子吸收法测定了大米中的镍,该方法具有简便、快速、结果准确可靠的优点。测定结果表明:镍的浓度在0~25μg/L范围线性良好,相关系数0.9991,镍的加标回收率为97.3%~104.2%;测定结果的相对标准偏差为1.9%,检出限为0.152μg/L。%This article adopts microwave digestion technology to process the sample and uses graphite furnace atomic absorption spectrometry to determine the trace Nickel in rice .The proposed method is proved to be rapid ,simple and accurate .The test results show that the linear range of Nickel is 0-25μg/L with a correlation coefficient of 0 .9991 . T he adding standard recovery is in the range of 97 .3% - 104 .2% , the RSD is 1 .9 ﹪ , and detection limit is 0 .152μg/L .

  2. 微波消解ICP-AES法测定绞股蓝中微量元素%Determination of trace elements in gynostemma pentaphylla by microwave digestion and ICP-AES

    Institute of Scientific and Technical Information of China (English)

    席晓岚; 季宇飞; 曾广铭; 徐红; 李明炬

    2009-01-01

    The trace elements of Cu,Fe,Mn,Co,Zn,Cr,Mg,Ga,Sr and Ca in the Chinese herbal medicine gynostemma pentaphylla were determined by the method of microwave digestion of samples,inductively coupled plasma atomic emission spectrometry (ICP-AES). At the optimum working conditions of the equipment,the recovery of elements is 87% -117% and the relative standard deviation (RSD) is less than 5. 91%. This research result has certain pracitcal interests in the study of the relationship between cardiovascular disease and trace elements in Chinese herbal medicine.%采用微波消解样品,电感耦合等离子体-原子发射光谱法(ICP-AES)测定了中药材绞股蓝中Cu、Fe、Mn、Co、Zn、Cr、Mg、Ga、Sr、Ca等微量元素的含量.在最佳仪器工作条件下,各元素的加标回收率在87%~117%,相对标准偏差RSD<5.91%,分析结果对中药材中的微量元素与心血管疾病关系的研究具有一定的实际意义.

  3. Wheat bran reduces concentrations of digestible, metabolizable, and net energy in diets fed to pigs, but energy values in wheat bran determined by the difference procedure are not different from values estimated from a linear regression procedure.

    Science.gov (United States)

    Jaworski, N W; Liu, D W; Li, D F; Stein, H H

    2016-07-01

    An experiment was conducted to determine effects on DE, ME, and NE for growing pigs of adding 15 or 30% wheat bran to a corn-soybean meal diet and to compare values for DE, ME, and NE calculated using the difference procedure with values obtained using linear regression. Eighteen barrows (54.4 ± 4.3 kg initial BW) were individually housed in metabolism crates. The experiment had 3 diets and 6 replicate pigs per diet. The control diet contained corn, soybean meal, and no wheat bran. Two additional diets were formulated by mixing 15 or 30% wheat bran with 85 or 70% of the control diet, respectively. The experimental period lasted 15 d. During the initial 7 d, pigs were adapted to their experimental diets and housed in metabolism crates and fed 573 kcal ME/kg BW per day. On d 8, metabolism crates with the pigs were moved into open-circuit respiration chambers for measurement of O consumption and CO and CH production. The feeding level was the same as in the adaptation period, and feces and urine were collected during this period. On d 13 and 14, pigs were fed 225 kcal ME/kg BW per day, and pigs were then fasted for 24 h to obtain fasting heat production. Results of the experiment indicated that the apparent total tract digestibility of DM, GE, crude fiber, ADF, and NDF linearly decreased ( ≤ 0.05) as wheat bran inclusion increased in the diets. The daily O consumption and CO and CH production by pigs fed increasing concentrations of wheat bran linearly decreased ( ≤ 0.05), resulting in a linear decrease ( ≤ 0.05) in heat production. The DE (3,454, 3,257, and 3,161 kcal/kg for diets containing 0, 15, and 30% wheat bran, respectively for diets containing 0, 15, and 30% wheat bran, respectively), ME (3,400, 3,209, and 3,091 kcal/kg for diets containing 0, 15, and 30% wheat bran, respectively), and NE (1,808, 1,575, and 1,458 kcal/kg for diets containing 0, 15, and 30% wheat bran, respectively) of diets decreased (linear, ≤ 0.05) as wheat bran inclusion increased

  4. Microwave engineering

    CERN Document Server

    Pozar, David M

    2012-01-01

    The 4th edition of this classic text provides a thorough coverage of RF and microwave engineering concepts, starting from fundamental principles of electrical engineering, with applications to microwave circuits and devices of practical importance.  Coverage includes microwave network analysis, impedance matching, directional couplers and hybrids, microwave filters, ferrite devices, noise, nonlinear effects, and the design of microwave oscillators, amplifiers, and mixers. Material on microwave and RF systems includes wireless communications, radar, radiometry, and radiation hazards. A large

  5. Microwave Digestion of Hair Samples in Closed Vessels for the Determinations of Copper and Iron by Derivative Flame Atomic Absorption Spectrometry using Flow-injection Technique%微波溶样-流动注射-导数火焰原子吸收光谱测定人发中的铜和铁

    Institute of Scientific and Technical Information of China (English)

    陈兰菊; 郑连义; 孙汉文

    2002-01-01

      本文以微波消解人发样,利用流动注射-导数火焰原子吸收法测定其中微量铜、铁的含量。微波溶样技术具有快捷、污染小、损失少、消化完全等优点;流动注射进样技术可以克服常规火焰原子吸收法耗样量大和基体干扰严重的缺点;导数技术应用于火焰原子吸收可提高方法的灵敏度和信号的选择性。微波溶样、流动注射与导数技术相结合应用于火焰原子吸收成功地测定了人发中的微量铜和铁。%  A new method was presented for the determinations of copper and iron in hair samples,which was based on the technique of microwave digestion in closed vessels,flow-injection and derivative flame atomic absorption spectrometry. The technique of microwave digestion is convenient, little of pollution, less in loss, and complete digestion. The flaws that sampling is large and matrix interference is serious in conventional flame atomic absorption spectrometry(FAAS) were overcome by flow-injection sampling technique. The sensitivity and signal selectivity were enhanced when derivative technique was used. This new method that derivative flame atomic absorption spectrometry combined with microwave digestion and flow-injection technique is simple and rapid with satisfactory results for determination of copper and iron in hair.

  6. Immobilization of trypsin on graphene oxide for microwave-assisted on-plate proteolysis combined with MALDI-MS analysis.

    Science.gov (United States)

    Xu, Guobin; Chen, Xiaoyi; Hu, Jianhua; Yang, Pengyuan; Yang, Dong; Wei, Liming

    2012-06-21

    With an ultra-high surface area and abundant functional groups, graphene oxide (GO) provides an ideal substrate for the immobilization of trypsin. We demonstrated that trypsin could be immobilized on GO sheets assisted by polymers as molecular spacers to maintain the activity of the enzyme. And with the trypsin-linked GO as the enzyme immobilization probe, a novel microwave-assisted on-plate digestion method has been developed with subsequent analysis by MALDI-MS. The feasibility and performance of the digestion approach were demonstrated by the proteolysis of standard proteins. The results show that this novel approach substantially accelerated proteolysis and reduced the time required for traditional procedures involving on-plate enzymatic digestion and sample preparation prior to MALDI-MS analysis. The novel digestion approach is simple and efficient, offering great promise for high throughput protein identification.

  7. Digestão de óleo lubrificante encapsulado em forno de microondas com radiação focalizada por adição de amostra ao reagente pré-aquecido

    Directory of Open Access Journals (Sweden)

    Flavia A. Bressani

    2006-12-01

    Full Text Available The applicability of the recently proposed procedure based on gradual sample addition to microwave-assisted pre-heated concentrated acid is limited by the sample viscosity. In this work, lubricating oil samples with high viscosity were encapsulated and manually added to the microwave-assisted pre-heated concentrated digestion mixture. The procedure was applied for determination of Al, Ca, Cr, Cu, Fe, Mg, Ni, P, Pb, Si, Sn, Sr, V, W, and Zn in lubricating oil by inductively coupled plasma optical emission spectrometry (ICP OES. Determined and certified values for Ca, Mg, P, and Zn in lubricating oil were in agreement at a 95% confidence level.

  8. Simultaneous Determination of 14 Inorganic Elements in Chimonanthus Praecox by ICP-OES with Microwave Digestion%微波消解-ICP-OES法同时测定腊梅花中的14种无机元素

    Institute of Scientific and Technical Information of China (English)

    张玲帆; 张文清; 夏玮; 刘鑫; 陶卫; 张磊

    2014-01-01

    采用微波消解法(6 mL HNO3和1 mL H2O2)对腊梅花样品进行前处理,优化了实验条件,建立了电感耦合等离子体发射光谱仪(ICP-OES)同时测定腊梅花样品中14种无机元素的方法。实验结果表明:腊梅花中K的含量高达2.47%;Ca、Mg的含量分别为0.30%和0.18%;Fe、Al、Na、Zn、Cu、Mn、Ba、B、Ni、Pb、Cr的含量为微量。待测元素的方法检出限为0.23 mg/kg~1.4 mg/kg;加标回收率在96.1%~110.0%之间,相对标准偏差小于4%。%The method for determination of 14 inorganic elements in Chimonanthus praecox by inductively coupled plasma optical emission spectrometry (ICP-OES) was researched. The Chimonanthus praecox samples were digested by closed-vessel microwave (6 mL HNO3 and 1 mL H2O2)digestion system. The condition of instrument was optimized. The experimental results showed that the content of Potassium was as high as 2.47%;Calcium,Magnesium were 0.30 % and 0.18 %, respectively; Iron, Aluminium, Copper, Zinc, Sodium, Manganese, Barium, Boron, Nickel, Lead and Chromium were trace levels. The detection limit of method for elements was in range of 0.23 mg/kg-1.4 mg/kg, the recovery was from 96.1 % to 110.0 %, and the relative standard deviation was less than 4%.

  9. Determination of Trace Elements in Quinoa by Microwave Digestion and ICP-OES%微波消解-ICP-OES法测定藜麦中的微量元素∗

    Institute of Scientific and Technical Information of China (English)

    邓文聪; 王妮; 付治国; 范建凤

    2016-01-01

    建立了电感耦合等离子体发射光谱法( ICP-OES)测定藜麦皮、带皮藜麦、去皮藜麦中微量元素含量测定的分析方法。采用HNO3+HCl混合酸为消解体系,用微波消解法对藜麦皮、带皮藜麦、去皮藜麦样品进行前处理, ICP-OES法测定其中Mn、 Cu、 K、 Ca、 Fe、 Zn、 Mg的含量。结果表明:藜麦皮、带皮藜麦、去皮藜麦中含有大量的人体必需的微量元素,藜麦皮中微量元素的含量大于去皮藜麦中的含量。对照GBW08503B-小麦成分分析标准, Mg、 K、 Ca在带皮藜麦、藜麦皮、去皮藜麦中的含量远远高于其在小麦中的含量, Mn、 Fe、 Zn的含量与小麦中的接近,而Cu的含量略低于其小麦中的含量。该方法操作简便、准确,可用于藜麦中微量元素含量的测定。%A method was established for the determination of trace elements content in quinoa oatmeal, the quinoa with skin and peeled quinoa by inductively coupled plasma Atomic emission spectrometry ( ICP-OES) . The sample was digested with HNO3+HCl mixed system by microwave digestion pre-treatment. The contents of seven elements ( Mn, Cu, K, Ca, Fe, Zn and Mg) were determined by ICP-OES. Results showed that quinoa oatmeal, the quinoa with skin and peeled quinoa rich in essential trace elements and quinoa oatmeal was greater than the content of trace elements than the peeled quinoa. Compared with GBW08503B-wheat ingredients analysis standard, the contents of Mg, K and Ca in quinoa oatmeal, the quinoa with skin and peeled quinoa were much higher than that of wheat, the contents of Mn, Fe and Zn closed to wheat, and the content of Cu was slightly lower than that of wheat. The method is simple and accurate, can perform simultaneous multi-elements determination of trace elements in quinoa.

  10. Microwave Ovens

    Science.gov (United States)

    ... ovens heat food using microwaves, a form of electromagnetic radiation similar to radio waves. Microwaves have three characteristics ... that their microwave oven products meet the strict radiation safety standard ... if your microwave oven has damage to its door hinges, latches, or seals, or ...

  11. Anaerobic digestion of straw after microwave pretreatment with acid%酸解微波预处理对秸秆厌氧消化的促进作用

    Institute of Scientific and Technical Information of China (English)

    冯磊; 李润东; 李延吉

    2009-01-01

    以秸秆为研究对象,比较微波酸化预处理作用下对秸秆厌氧消化产气特性的影响,实验中研究甲烷产生速率、pH值、甲烷气体体积分数及生物降解率4个参数的变化趋势,结果表明:①微波酸化预处理对秸秆厌氧消化有明显效果,累计产甲烷气量由未被预处理的186.1mL·g~(-1)上升到245.4~303.4 mL·g~(-1)(以有机物质计),达到最大甲烷产生速率时间由原来的第12d.提前至4-11d不等,最大甲烷产生速率由原来的14.11mL·g~(-1)·d~(-1)上升到18.64~33.19 mL·g~(-1)·d~(-1);②经过微波酸化预处理的甲烷体积分数由原来的52.1%提高至64.5%左右,其生物能范围也由未处理前的19.71 MJ·m~(-3)提高至24.41 MJ·m~(-3),物料降解率由未预处理的44.1%.提高至64.25%.%High-energy biogas was generated through anaerobic digestion of straw pretreated with acid and microwave energy. In laboratory experiments, the pH, gas production rate and concentration of methane in the gas were monitored. The main conclusions are: ① There was an obvious effect of microwave acidification pretreatment on the efficiency of anaerobic digestion of the straw. The average accumulated gas production from non-pretreated and pretreated straw amounted to 186. 1 and 245. 4 ~ 303. 4 mL · g~(-1), respectively, a significant increase after pretreatment. The maximum daily gas production was also increased to 14. 11 and 18.64 to 33. 19 mL·g~(-1)·d~(-1) , respectively, and was reached after a distinctly shorter period of time ( 12 d for non-treated straw, but 4 to 11 d for the pretreated straw) . ② The CH_4 concentration in the biogas increased from 52. 1 % to 64. 5% , which is equivalent to an increase in bio - energy yield from 19. 71 to 24. 41 MJ·m~(-3). Furthermore, the extent of mineralization was increased from 44. 1% to 64. 25% .

  12. Microwave digestion-Graphite Furnace Atomic Absorption Spectrometry of the arsenic content in tissue paper%微波消解-石墨炉原子吸收法测定纸巾纸中砷含量

    Institute of Scientific and Technical Information of China (English)

    陈智飞; 李达光; 易碧华

    2015-01-01

    To establish a method for determination of arsenic content in tissue paper by graphite furnace atomic absorption spectrometry.Using microwave digestion of smple,with matrix modifier of nickel nitrate,determination of arsenic by graph⁃ite furnace atomic absorption spectrometry. The results showed that the determination,a regression equation is Y=0.0025X+0.0004,correlation coefficient r=0.9996. The detection limit is 0.12 ug/L,the recovery is 95.8%~100.3%,the relative standard deviation is 2.37%. The method is rapid,accurate,high sensitivity,suitable for detection of arsenic content in tis⁃sue paper.%建立了石墨炉原子吸收光谱法测定纸巾纸中砷含量的方法。采用微波消解技术处理样品,加入基体改进剂硝酸镍,应用石墨炉原子吸收光谱法测定砷。结果表明,测定一次回归方程为Y=0.0025X+0.0004,相关系数r=0.9996。检出限为0.12 ug/L,回收率为95.8%~100.3%,相对标准偏差为2.37%。该方法具有快速、准确、灵敏度高等优点,适用于纸巾纸中砷含量的检测。

  13. 微波消解ICP-MS测定猪肉中9种金属元素%Determination of 9 Kinds of Metal Elements in Pork Muscle by Microwave Digestion and ICP-MS

    Institute of Scientific and Technical Information of China (English)

    李爱军; 郑百芹; 庞学良; 董李学; 张鑫; 周鑫; 汤思凝; 项爱丽

    2015-01-01

    对采用微波消解ICP-MS测定猪肉中砷、镉、铅、镍、铬、铜、汞、锑和锌9种金属元素的含量进行了研究。结果表明,方法测定的线性范围在0~50 ng/mL,检出限为1.2~22.5 ng/mL,精密度在0.28%~4.39%之间,猪肉样品添加回收率为81.5%~112.6%。该方法操作简便、快速、准确,大大提高了检测时效。%In this paper, we introduced the determination of 9 kinds of metal elements, arsenic, cadmium, lead, nickel, chromium, copper, mercury, antimony and zinc in pork muscle, by microwave digestion and ICP-MS. The linear range of standard curve was from 0 to 50 ng/mL, the detection limit was within the range of 1. 2~22.5 ng/mL, and the precision of the method was 0.28%~4.39%. All the recovery rates in meat were between 81.5% and 112. 6%. The method we used in this paper was simple, rapid and accurate, which may greatly improve the detection time and efficiency.

  14. Determination of 20 elements in Foeniculum vulgare Mill by microwave digestion and ICP-AES%微波辅助消解ICP-AES法测定小茴香中20种元素

    Institute of Scientific and Technical Information of China (English)

    陈燕芹; 刘红

    2014-01-01

    采用微波消解法处理小茴香样品,电感耦合等离子体发射光谱( ICP-AES)测定其中Na、K、Sr、Ca、Mg、P、As、Zn、Pb、Co、Cd、Ni、Ba、Fe、Mn、Cr、Cu、Al、Ti 和 B 20种常量和微量元素的含量。20种元素的检出限为0.00002~0.00468μg·mL-1,回收率为89.50%~107.89%,相对标准偏差( RSD)均小6%。结果显示,小茴香果实及其嫩叶中除含有人体必需的常量元素K,Na,Ca,Mg,P外,还含有Fe、Zn、Mn、Cr、Co等必需的微量元素和其他元素Ti、B、Ni、Al、Sr、Ba等。%The contents of 20 elements of Na,K,Sr,Ca,Mg,P,As,Zn,Pb,Co,Cd,Ni,Ba,Fe,Mn,Cr,Cu,Al,Ti and B in Foenicu-lum vulgare Mill were determined by ICP-AES,and the samples were pretreated by microwave digestion method. The detection limits were 0. 00002~0. 00468 μg·mL-1 ,and the recovery rates were 89. 50% ~107. 89%,the precisions were less than 6%. Five mac-roelements,K,Na,Ca,Mg and P,five essential microelements,Fe,Zn,Mn,Cr and Co,and seven other elements,Ti,B,Ni,Al,Sr and Ba were detected in all samples.

  15. 微波消解-ICP-AES法测定回汉族人群血清中的微量元素%Determination of serum trace elements of Hui and Han ethnic by ICP-AES after microwave digestion

    Institute of Scientific and Technical Information of China (English)

    李玲; 樊学敏; 靳雅男; 赵燚

    2014-01-01

    The concentration of serum mineral elements of rural residents in Ningxia was determined by ICP-AES in this work. Microwave digestion was used for sample decomposition. By this way, RSD≤3. 5%and the average recoveries were in the range of 90%-117%. The method is simple,rapid,sensitive and accurate for the determination of various elements in the same ser-um. The results show that,there are significant difference between Hui ethnic group and Han ethnic group in 14 elements(P<0. 05) . At the same time,the reasons which caused differences were explained.%本文测定了宁夏农村地区回汉族人群血清中Li、Co、Cd、Ga、Ba、Sr、Cu、Zn、Fe、Al、Se、Sn、B、Mn、Cr、Ni、Pb、Ca、K、Mg、Na、P、S的含量。采用微波消解对样品进行了前处理,使用电感耦合等离子体原子发射光谱法( ICP-AES)进行测定。该方法的RSD≤3.5%,样品加标回收率为90%~117%。该法简便、快速、灵敏、准确,可用于血清中多种元素含量的同时测定。研究结果表明,K、Fe、Cu、Mn、Ni、Ga、Al、Se、Pb、S、Cd、Cr、Sr、Ca这14种元素含量在回族和汉族之间存在着显著性差异(P<0.05),探讨了产生上述差异的原因。

  16. Microwave imaging

    CERN Document Server

    Pastorino, Matteo

    2010-01-01

    An introduction to the most relevant theoretical and algorithmic aspects of modern microwave imaging approaches Microwave imaging-a technique used in sensing a given scene by means of interrogating microwaves-has recently proven its usefulness in providing excellent diagnostic capabilities in several areas, including civil and industrial engineering, nondestructive testing and evaluation, geophysical prospecting, and biomedical engineering. Microwave Imaging offers comprehensive descriptions of the most important techniques so far proposed for short-range microwave imaging-in

  17. Fast Decomposition Procedure of Solid Samples by Lithium Borates Fusion Employing Salicylic Acid.

    Science.gov (United States)

    Trdin, Miha; Nečemer, Marijan; Benedik, Ljudmila

    2017-03-07

    A new fast decomposition procedure for solid samples was developed. In this study, we investigated decomposition of samples by lithium borates fusion in combination with salicylic acid. The method described shortens the time required for the sample to be digested and loaded to a resin to up to 2 h, and it was especially suitable for alpha spectrometry measurements in emergency situations. Additionally, the method results in high radiochemical recoveries and when compared to other digestion methods (classical digestion utilizing mineral acids, microwave digestion, and lithium borates fusion in combination with polyethylene glycol (PEG)) gives comparable activity concentration values. The method used was applied to various reference materials with inorganic and organic matrices as well as widely varying amounts of uranium radioisotopes content. The results obtained were compared with reference and literature values and show that the proposed method can be successfully implemented on various types of samples.

  18. Effects of different modified diets on growth, digestive enzyme activities and muscle compositions in juvenile Siamese fighting fish (Betta splendens Regan, 1910)

    OpenAIRE

    Thongprajukaew, Karun; Kovitvadhi, Uthaiwan; Kovitvadhi, Satit; Somsueb, Pisamai; Torrissen, Krisna Rungruangsak

    2011-01-01

    The effects of four modified diets (gamma-irradiated, microwave-irradiated, probiotic-supplemented and carbohydrase-supplemented diets) were studied on digestive enzyme specific activities and growth performance quality of juvenile Siamese fighting fish (Betta splendens Regan, 1910) during 2 weeks of critical and intensive rearing period. The modified procedures did not change biochemical compositions and gross energy of diets, but generally resulted in relatively higher in vitro ...

  19. Micro-scaled high-throughput digestion of plant tissue samples for multi-elemental analysis

    Directory of Open Access Journals (Sweden)

    Husted Søren

    2009-09-01

    Full Text Available Abstract Background Quantitative multi-elemental analysis by inductively coupled plasma (ICP spectrometry depends on a complete digestion of solid samples. However, fast and thorough sample digestion is a challenging analytical task which constitutes a bottleneck in modern multi-elemental analysis. Additional obstacles may be that sample quantities are limited and elemental concentrations low. In such cases, digestion in small volumes with minimum dilution and contamination is required in order to obtain high accuracy data. Results We have developed a micro-scaled microwave digestion procedure and optimized it for accurate elemental profiling of plant materials (1-20 mg dry weight. A commercially available 64-position rotor with 5 ml disposable glass vials, originally designed for microwave-based parallel organic synthesis, was used as a platform for the digestion. The novel micro-scaled method was successfully validated by the use of various certified reference materials (CRM with matrices rich in starch, lipid or protein. When the micro-scaled digestion procedure was applied on single rice grains or small batches of Arabidopsis seeds (1 mg, corresponding to approximately 50 seeds, the obtained elemental profiles closely matched those obtained by conventional analysis using digestion in large volume vessels. Accumulated elemental contents derived from separate analyses of rice grain fractions (aleurone, embryo and endosperm closely matched the total content obtained by analysis of the whole rice grain. Conclusion A high-throughput micro-scaled method has been developed which enables digestion of small quantities of plant samples for subsequent elemental profiling by ICP-spectrometry. The method constitutes a valuable tool for screening of mutants and transformants. In addition, the method facilitates studies of the distribution of essential trace elements between and within plant organs which is relevant for, e.g., breeding programmes aiming at

  20. Protein digestibility of ruminant feeds by the three-step procedure Digestibilidade da proteína de alimentos utilizados na alimentação de ruminantes pelo método das três etapas

    Directory of Open Access Journals (Sweden)

    Norberto Mario Rodíguez

    2007-12-01

    Full Text Available The three-step procedure was used to evaluate ruminal degradable and undegradable protein of soybean meal (SM, sorghum grain (SG, cottonseed (CT, corn silage (CS and tomato byproduct (TBP. Feeds were initially incubated in rumen of fistulated steers for 16 h. After that, 15mg of nitrogen were submitted to acid pepsin, for one hour, and alkaline pepsin for 24 h. The SM and CT showed 97 and 93% total protein digestibility, which is the major portion available in the rumen (94 and 92% respectively. The SG protein showed the lowest digestibility (73% followed by TBP and CS that had 72 and 73% total protein digestibility. It was concluded that SM and CT showed high protein digestibility, however the most portion was degraded in the rumen and that besides the high lignin proportion, the TBP was the one which supplied more available intestinal protein.Avaliaram-se as proporções de proteína degradável e não-degradável no rúmen do farelo de soja (FS, sorgo grão (SG, caroço de algodão (CA, silagem de milho (SM e do resíduo industrial de tomate (RIT pelo método das três etapas. Os alimentos foram inicialmente incubados por 16h no rúmen de bovinos fistulados. Posteriormente, uma quantidade que continha 15mg de nitrogênio foi submetida à digestão em pepsina ácida por uma hora e em pancreatina alcalina por 24h. O FS e o CA apresentaram 97 e 93% de digestibilidade da PB, estando a maior parte desse nitrogênio disponível no rúmen (94 e 92% respectivamente. A proteína do SG apresentou o menor valor de digestibilidade (64%, sendo seguida pelo RIT e pela SM, que apresentaram 72 e 73% de proteína total digestível. Concluiuse que o FS e o CA apresentaram elevada digestibilidade da proteína, entretanto, a maior parte do desaparecimento ocorreu no rúmen. Apesar da elevada proporção de proteína indigestível, o RIT foi o alimento que mais disponibilizou proteína para ser digerida no intestino.

  1. Microwave Photonics

    OpenAIRE

    Seeds, A.J.; Liu, C. P.; T. Ismail; Fice, M. J.; Pozzi, F; Steed, R. J.; Rouvalis, E.; Renaud, C.C.

    2010-01-01

    Microwave photonics is the use of photonic techniques for the generation, transmission, processing and reception of signals having spectral components at microwave frequencies. This tutorial reviews the technologies used and gives applications examples.

  2. Comparison of sample digestion techniques for the determination of trace and residual catalyst metal content in single-wall carbon nanotubes by inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Grinberg, Patricia, E-mail: patricia.grinberg@nrc.ca [Measurement Science and Standards, National Research Council Canada, Ottawa (Canada); Sturgeon, Ralph E. [Measurement Science and Standards, National Research Council Canada, Ottawa (Canada); Diehl, Liange de O.; Bizzi, Cezar A. [Measurement Science and Standards, National Research Council Canada, Ottawa (Canada); Chemistry Department, Universidade Federal de Santa Maria, Santa Maria (Brazil); Flores, Erico M.M. [Chemistry Department, Universidade Federal de Santa Maria, Santa Maria (Brazil)

    2015-03-01

    A single-wall carbon nanotube material produced by laser ablation of renewable biochar in the presence of Ni and Co catalyst was characterized for residual catalyst (Co and Ni) as well as trace metal impurity content (Fe, Mo, Cr, Pb and Hg) by isotope dilution ICP-MS following sample digestion. Several matrix destruction procedures were evaluated, including a multi-step microwave-assisted acid digestion, dry ashing at 450 °C and microwave-induced combustion with oxygen. Results were benchmarked against those derived from neutron activation analysis and also supported by solid sampling continuum source GF-AAS for several of the elements. Although laborious to execute, the multi-step microwave-assisted acid digestion proved to be most reliable for recovery of the majority of the analytes, although content of Cr remained biased low for each approach, likely due to its presence as refractory carbide. - Highlights: • Determination of trace and residual catalyst metal content in Single-Wall Carbon Nanotubes by Inductively Coupled Plasma Mass Spectrometry. • Comparative study of digestion methodology combined with high precision isotope dilution ICP-MS for quantitation of elements of toxicologic relevance. • Results were benchmarked against those derived from neutron activation analysis and also supported by solid sampling continuum source GF-AAS for several of the elements.

  3. Simultaneous Determination of Arsenic and Mercury in PM2.5 by Microwave Digestion-AFS%微波消解-原子荧光法同时测定PM2.5中砷、汞含量

    Institute of Scientific and Technical Information of China (English)

    欧阳开

    2013-01-01

    Microwave digestion and atom fluorescence spectrometry were used to determine arsenic and mercury in PM2.5. The results showed that the best fluorescence intensity in simultaneous determination of arsenic and mercury was acquired as reductant KBH4 mass fraction was 2%and HCl volume fraction was 4%. The method detection limit of arsenic and mercury were 0.027, 0.006μg/L respectively. The recovery of the blank spike samples was 95.3%-101.7%for As and 96.0%-106.0% for Hg. The recovery of the spike samples were 95.0%-103.5%, 93.3%-110.0% for As and Hg, respectively. The method has high accuracy and low detection limit, it is suitable for the determination of arsenic and mercury in PM2.5.%采用微波消解-原子荧光法测定PM2.5中砷、汞含量。实验结果表明,当还原剂硼氢化钾的质量分数为2%、溶液介质酸度为4%(体积分数)盐酸时,同时测定砷、汞可获得最佳的荧光值。砷、汞测定的检出限分别为0.027,0.006μg/L,空白滤膜的加标回收率分别为95.3%~101.7%,96.0%~106.0%,样品的加标回收率分别为95.0%~103.5%,93.3%~110.0%。该法检出限低,准确度高,适用于环境空气PM2.5中砷、汞含量的测定。

  4. 微波消解-离子色谱法测定面制品中磷酸盐含量%Determination of phosphate in wheat flour products by microwave digestion -ion chromatography

    Institute of Scientific and Technical Information of China (English)

    杨笑; 陈波

    2014-01-01

    为建立用微波消解进行样品前处理,离子色谱法测定面制品中的磷酸盐含量的检测方法。用离子色谱带电导检测器进行分离测定,色谱柱为 IonPac AS19(4×250 mm),35 mmol /L 氢氧化钾为淋洗液,流速为1.0 mL/min。结果表明加标回收率在97.0%~115.0%范围,相对标准偏差均小于0.5%,在1.0~50.0 mg/L 范围呈现良好的线性关系,回归系数大于0.999。该法具有操作简便、分析快速、准确等优点,能满足面制品中磷酸盐含量检测要求。%Phosphate in wheat flour products,which was pretreated by microwave digestion technique, was determined by ion chromatography equipped with a conductivity detector.The chromatographic col-umn was IonPac AS19(4 ×250 mm)and the mobile phase was 35 mmol /L KOH solution at a flow rate of 1.0 mL/min.The result showed that the recovery rate for this method was 97.0%~115.0% and the rel-ative standard deviation was less than 0.5% .The linear regression coefficientwas higher than 0.999 within the concentration range of 1.0 ~50.0 mg/L.As a simple and rapid testing,this method showed satisfied accuracy and was suitable for the determination of phosphate in wheat flour products.

  5. Determination of Arsenic and Antimony in Leather by Atomic Fluorescence Spectrometry with Microwave Digestion%微波消解—原子荧光光谱法同时测定皮革中的砷和锑

    Institute of Scientific and Technical Information of China (English)

    吕小园; 陈新焕; 肖家勇; 刘正华; 陈练; 杨万彪; 黄红; 张志荣

    2012-01-01

    建立了皮革及其制品中砷和锑的微波消解-原子荧光光谱测定方法,方法准确、灵敏,快速.在优化的试验条件下,砷浓度在0.5~150 ng/mL范围内成线性关系,相关系数r=0.9995,检出限为0.22 ng/mL,回收率为99.4%~104.2%:锑浓度在0.5~ 120 ng/mL范围内成线性关系,相关系数r=0.9998,检出限为0.16 ng/mL,回收率为101.1%~106.7%.相对标准偏差(n=5)均小于5%.方法应用于皮革及其制品中砷和锑的测定,结果满意.%An accurate, sensitive and quick method for determination of arsenic and antimony in leather by atomic fluorescence spectrometry with microwave digestion was developed in this paper. Under the optimized condition, the result of arsenic showed that the linear range was 0.5 - 150 ng/mL(r =0. 9995), the limit of detection was 0. 22 ng/mL, and the average recoveries in leather ranged form 99. 4% to 104. 2% . The linear range of antimony was 0. 5 ~ 120 ng/mL( r = 0.9998) , the limit of detection was 0. 16 ng/mL, the average recoveries ranged form 101. 1% tol06.7%. TheRSD(n=5) were all lower than 5%. It has been applied to routine determination of arsenic and antimony in leather with satisfactory results.

  6. Determination of Metallic Element in Soybean Coat by Fermentation-Microwave Digestion-Microwave after Semi-Ashing Plasma Torch Atomic Emission Spectrometry%半灰化-微波消解-MPT-AES测定大豆皮中的金属元素

    Institute of Scientific and Technical Information of China (English)

    李秀萍; 赵荣祥; 李丽华; 张金生

    2011-01-01

    Soybean coat samples were digested by H202-HNO3 solution after semi-ashing in a closed microwave system and the determination of iron,nickel,magnesium,calcium zinc and copper in soybean coat has been performed hy MPT-AES. Experimental conditions were optimized and established. The effects of acid concentration and coexisting ions( K, Na, Fe,Ni ,Al,Zn, M g,Ca)on determination of iron,nickel,magnesium,calcium zinc and copper were investigated. The results showed that the detection limits of iron, nickel, magnesium, calcium, zinc and copper were 22.94,7.55,0.36,0.92,16.27 and 2. 1 ng ·mL -1 , respectively. The RSD was no more than 3.2% , it showed the adopted method had good precision. The linear ranges of iron,nickel,magnesium,calcium, zinc and copper were 0-12, 0-12, 0-35, 0-32, 0-7 and 0-12 μg · mL-1, respectively. The recoveries were 96.8% -101.3% ,98.4% -103.7% , 95.9% -99.6% , 96.3% -103.5% , 99.8% -103.5% and 97.6%-105.3% , respectively. Compared with conventional test methods, MPT combined with half ash and microwave digestion samples was efficient with high accuracy and repeatability and applicable to sample analysis.%采用半灰化HNO3-H2O2消解大豆皮,微波等离子体矩原子发射光谱(MPT-AES)测定其中铁、镍、镁、钙、锌和铜的含量,同时详细考察了测定各金属元素的最佳试验条件以及介质酸和共存离子的影响.结果表明:测定铁、镍、镁、钙、锌、铜的检出限分别为22.94、7.55、0.36、0.92、16.27、2.1 ng·mL-1,RSD小于3.2%,说明方法精密度较高,线性范围分别为0~12、0~12、0~35、0~32、0~7、0~12μg·mL-1,加标回收率分别为96.8%~101.3%、98.4%~103.7%、95.9%~99.6%、96.3%~103.5%、99.8%~103.5%、97.6%~105.3%.与常规试验方法相比,MPT-AES法与半灰化和微波消解处理样品相结合具有快速、准确性和重复性高的特点,适用于样品分析.

  7. Digestive Diseases

    Science.gov (United States)

    ... Celiac Disease Bowel Control Problems (Fecal Incontinence) Gas Lactose Intolerance Diarrhea Diverticulosis & Diverticulitis Acid Reflux (GER & GERD) More Digestive Disease Topics Children and Teens Acid Reflux (GER & GERD) in Infants Acid Reflux (GER & GERD) in Children & Teens Chronic ...

  8. Raman, infrared and XPS study of bamboo phytoliths after chemical digestion.

    Science.gov (United States)

    Watling, Kym M; Parr, Jeff F; Rintoul, Llew; Brown, Christopher L; Sullivan, Leigh A

    2011-10-01

    Raman, infrared and X-ray photoelectron spectroscopies have been used to examine the effect of various chemical digestion methods on the composition of bamboo phytoliths. Intact bilobate phytoliths, suitable for interrogation by Raman microprobe analysis, were isolated by a microwave wet ashing technique using hydrogen peroxide with nitric and hydrochloric acids. The occluded phytolith carbon presented evidence of cellulose, lignin and carboxylic acids. Nitrate from the nitric acid used in the digestion was observed in homogenized samples of the isolated phytoliths; in addition to nitrogen of plant origin occluded within the phytolith, which was observed as amine nitrogen and ammonia. Intact bilobate phytoliths were not observed following an exothermic hydrogen peroxide/sulfuric acid digest, suggesting that these structures ruptured during this digestion procedure. The silicate network was significantly altered during isolation using the exothermic hydrogen peroxide/sulfuric digest, with surface hydroxyls undergoing condensation to form a SiO(3) ring structure. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. Determination Trace of Cadmium in Leather Products and Textiles by Graphite Furnace Atomic Absorption Spectrometry with Microwave Digestion%微波消解-石墨炉原子吸收光谱法测定皮革制品及纺织品中痕量镉

    Institute of Scientific and Technical Information of China (English)

    邓小文; 卫佳欢; 蒋小良; 黄钧; 徐正华

    2013-01-01

      研究建立了微波消解-石墨炉原子吸收光谱法测定皮革制品及纺织品中痕量镉的检验方法.样品经微波消解后,以硝酸镍为基体改进剂,试验了石墨炉原子吸收法测定镉的最佳仪器条件.在选定的最优测试条件下,镉的检出限为0.025滋g/L,样品加标回收率为96.5%~105.5%,相对标准偏差小于4.4%.用于皮革制品及纺织品中痕量镉的测定,结果满意.%A method for the determination of trace amounts of cadmium in leather products and textiles by graphite furnace atomic absorption spectrometry with microwave digestion was developed. The samples were digested by microwave. The optimal instrument conditions were established by nickel nitrate as matrix modifier. The detection limit of cadmium was 0.025 μg·L-1, and the recoveries range was 96.5%-105.5%, with relative standard deviation (RSD) below 4.4 %. The method can be used in the determination of trace amounts of cadmium in leather products and textiles with satisfactory results.

  10. Status of the membrane procedure - Possible applications to waste water digestion; Stand der Technik von Membranverfahren. Einsatzmoeglichkeiten bei der Vergaerung von Abwaessern

    Energy Technology Data Exchange (ETDEWEB)

    Engeli, H.; Edelmann, W.

    2001-07-01

    In waste water with low organic loadings anaerobic microorganisms are working at a low efficiency. The plant's energy balance becomes negative because a big need of process energy to warm up the 'unproductive' water is created. This can be dealt with by concentrating the waste waters my means of membrane systems. Separation of slightly loaded flows into purified permeate and digestible concentrate may therefore increase the potential of digestion in industrial waste water significantly. As a basis for this report the following connections were used: congresses and exhibitions, personal contacts with people and companies who work and have published in this field as well as data base research. According to the technical standard the different processes of nano filtration, ultrafiltration and reverse osmosis are used to purify industrial or domestic waste water. Therefore, the majority of classic suppliers of waste water technology offer membrane systems. The membrane bio-reactors belong to the typical systems used. In this system the biomass is separated and retained by a membrane. Due to this combination the volume of the reactor can be reduced and the grade of degradation increased. Simultaneously a permeate is produced which can reach the quality of the desired effluent and which can be re-used manifold. Additional concentration of weakly loaded waste water to be used in a subsequent digestion can reduce energy consumption. Due to the fact that mainly the technical feasibility of the membrane technology was emphasised, some further evaluation in regard of energy consumption and cost has to be made. (author)

  11. 47 CFR Appendix I to Subpart E of... - A Procedure for Calculating PCS Signal Levels at Microwave Receivers (Appendix E of the...

    Science.gov (United States)

    2010-10-01

    ... at Microwave Receivers (Appendix E of the Memorandum Opinion and Order) I Appendix I to Subpart E of... PERSONAL COMMUNICATIONS SERVICES Broadband PCS Pt. 24, Subpt. E, App. I Appendix I to Subpart E of Part 24... station and the characteristics of each receiver, i.e., adjacent channel susceptibility, antenna...

  12. Green and solvent-free procedure for microwave-assisted synthesis of 2,4,6-triarylpyridines catalysed using MgAl2O4 nanocrystals

    Indian Academy of Sciences (India)

    Javad Safari; Soheila Gandomi-Ravandi; Mahmoud Borjian Borujeni

    2013-09-01

    Design and development of a heterogeneous nanocatalyst for condensation reaction of acetophenone derivatives, aromatic aldehydes, and ammonium acetate to yield 2,4,6-triarylpyridines followed by microwave irradiation is described. Nanocrystalline MgAl2O4 as a novel heterogeneous recyclable catalyst shows high activity for the above reaction. In addition, the easily recoverable nanosized catalysts showed good reusability.

  13. Design Procedure for Compact Folded Waveguide Filters

    DEFF Research Database (Denmark)

    Dong, Yunfeng; Johansen, Tom Keinicke; Zhurbenko, Vitaliy;

    Waveguide filters are widely used in communication systems due to low losses and high power handling capabilities. One drawback of the conventional waveguide filters is their large size, especially for low-frequency and high-order realizations. It has been shown that the footprint of conventional...... waveguide resonators can be reduced to one quarter by folding the electric and magnetic fields inside the cavity (J. S. Hong, Microwave Symposium Digest, 2004, Vol. 1, pp. 213-216). This paper presents a novel systematic procedure for designing compact low-loss bandpass filters by using folded waveguide...... resonators. As a design example, a scaled version of a filter specified for a TETRA (Terrestrial Trunked Radio) system has been considered. The folded waveguide filter is designed to fulfil specific requirements, and the design procedure can be easily applied to other folded waveguide filter designs...

  14. Voltammetric and liquid chromatographic identification of organic products of microwave-assisted wet ashing of biological samples

    Energy Technology Data Exchange (ETDEWEB)

    Pratt, K.W.; Kingston, H.M.; MacCrehan, W.A.; Kock, W.F.

    1988-10-01

    Residual organic species in nitric acid digest of freeze-dried bovine liver (NBS SRM 1577a) have been identified by use of voltammetry, liquid chromatography, spectrophotometry, and classical chemical tests. Data from these techniques show that major products of microwave-assisted dissolution by nitric acid include o-, m-, and p-nitrobenzoic acids (NBA). In addition to these compounds, other organic species present in these digests irreversibly complex copper, but not zinc, and result in low values for copper by polarography. The NBAs and these other organic species are all eliminated by refluxing the nitric acid digest in perchloric acid at atmospheric pressure. Polarographic results obtained for copper following treatment with perchloric acid agree with the certified value. The use of voltammetry in the evaluation of wet ashing procedures is discussed.

  15. Simultaneous determination of arsenic, cadmium, calcium, chromium, cobalt, copper, iron, lead, magnesium, manganese, molybdenum, nickel, selenium, and zinc in fertilizers by microwave acid digestion and inductively coupled plasma-optical emission spectrometry detection: single-laboratory validation of a modification and extension of AOAC 2006.03.

    Science.gov (United States)

    Webb, Sharon; Bartos, James; Boles, Rhonda; Hasty, Elaine; Thuotte, Ethel; Thiex, Nancy J

    2014-01-01

    A single-laboratory validation study was conducted for the simultaneous determination of arsenic, cadmium, calcium, cobalt, copper, chromium, iron, lead, magnesium, manganese, molybdenum, nickel, selenium, and zinc in all major types of commercial fertilizer products by microwave digestion and inductively coupled plasma-optical emission spectroscopy analysis. This validation study proposes an extension and modification of AOAC 2006.03. The extension is the inclusion of calcium, copper, iron, magnesium, manganese, and zinc, and the modification is incorporation of hydrochloric acid in the digestion system. This dual acid digestion utilizes both hydrochloric and nitric acids in a 3 to 9 mL volume ratio/100 mL. In addition to 15 of the 30 original validation materials used in the 2006.03 collaborative study, National Institute of Standards and Technology Standard Reference Material 695 and Magruder 2009-06 were incorporated as accuracy materials. The main benefits of this proposed method are a significant increase in laboratory efficiency when compared to the use of both AOAC Methods 965.09 and 2006.03 to achieve the same objective and an enhanced recovery of several metals.

  16. Microwave circulator design

    CERN Document Server

    Linkhart, Douglas K

    2014-01-01

    Circulator design has advanced significantly since the first edition of this book was published 25 years ago. The objective of this second edition is to present theory, information, and design procedures that will enable microwave engineers and technicians to design and build circulators successfully. This resource contains a discussion of the various units used in the circulator design computations, as well as covers the theory of operation. This book presents numerous applications, giving microwave engineers new ideas about how to solve problems using circulators. Design examples are provided, which demonstrate how to apply the information to real-world design tasks.

  17. Microwave Microscope

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Makes ultra-high-resolution field measurements. The Microwave Microscope (MWM) has been used in support of several NRL experimental programs involving sea...

  18. Determination of arsenic and mercury in the rice by microwave digestion-atomic fluorescence spectrometry%大米中砷和汞的微波消解-原子荧光光谱测定法

    Institute of Scientific and Technical Information of China (English)

    李树雄; 张荣

    2012-01-01

    目的 建立双道原子荧光光谱法同时测定大米中的砷和汞的方法.方法 采用微波消解法处理大米样品,以原子荧光光谱法同时测定其中的砷和汞.结果 砷和汞的检出限分别为0.0044、0.039 μg/L;砷、汞标准溶液分别在1.0 ~20.0和0.10 ~1.20 μg/L范围内线性良好,其相关系数分别为0.9995、0.9992;精密度RSD:测定含2.0 μg/L砷和0.4 μg/L汞的混合标准溶液的RSD分别为2.12% 、4.59%.样品加标回收率:砷92.2% ~96.8%,汞90.3% ~92.1%.结论 该方法灵敏度、准确度高,操作方便快速,具有较低的检出限,能满足同时测定大米中砷和汞含量的测定工作.%[Objective ] To establish the method for simultaneous determination of trace arsenic and mercury in rice by dual-channel atomic fluorescence spectrometry. [Methods] The rice samples was digested by microwave, then the trace arsenic and mercury were simultaneously determined by Atomic fluorescence spectrometry. [ Results] The detection limits were 0.004 4 (μg/L for arsenic and 0.039 (μg/L for mercury; there was a linear relationship between 1.0-20.0 μg/L of arsenic standard solution, 0.10-1.20 (μg/L of mercury standard solution. The correlation coefficients were 0.999 5 for arsenic and 0.999 2 for mercury. The precision RSD was 2.12% for 2.0 μg/L arsenic mixed standard solution, and 4.59% for 0.4 μg/L mercury mixed standard solution. The recoveries were 92.2%-96.8% for arsenic and 90.3%-92.1% for mercury. [Conclusion]This method is very sensitive, with high accuracy, easy and fast. It has lower detecting limit, and can determine the content of Arsenic and Mercury in rice simultaneously

  19. Determination of 16 Rare Earth Elements in Banana by Microwave Digestion and ICP-MS%微波消解ICP-MS法结合同时测定香蕉中的16种稀土元素含量

    Institute of Scientific and Technical Information of China (English)

    范稚莉; 范稚莲; 闫飞燕; 莫磊兴; 王天顺; 廖洁; 牙禹; 范业赓

    2013-01-01

    [Objective] This study aimed to investigate the residues of rare earth ele-ments in Guangxi banana from banana-producing area with application of rare earth fertilizers and evaluate the safety of using rare earth fertilizers in banana production. [Method] HNO3+H2O2 mixed acid system with high pressure airtight microwave di-gestion sample pretreatment method and ICP-MS technology were used, to establish a determination method of 16 rare earth elements in banana samples, including Sc45, Y89, La139, Ce140, Pr141, Sm147, Eu153, Gb157, Tb159, Nd144, Dy163, Ho165, Er166, Tm169, Yb172 and Lu175. [Result] Different standard curves present-ed good linearity. Detection limit of the instrument was 0.002-0.01 μg/L; detection limit of the method was 0.1-0.6 μg/kg; recovery rate of standard addition was 94.5%-116%; relative standard deviation was 2.02%-14.21%. [Conclusion] This method has many advantages, such as simple mass spectrogram, high sensitivity and high selectivity, accurate quantification, high precision and accuracy, simple operation, high reproducibility and high recovery rate, which is suitable for the detection of rare earth elements in banana and other fruits, with certain theoretical and applicable val-ue for guiding banana production and high-efficient planting.%[目的]旨在了解广西香蕉产区施用稀土农用肥的稀土元素残留情况,指导香蕉生产,评价稀土农用肥的安全性。[方法]采用ICP-MS等离子体质谱法和使用HNO3+H2O2混酸体系高压密闭微波前处理样品联合技术,建立测定香蕉样品中16种稀土元素(Sc45,Y89,La139,Ce140, Pr141,Sm147,Eu153,Gb157,Tb159,Nd144, Dy163,Ho165,Er166,Tm169,Yb172,Lu175)含量的方法。[结果]各曲线呈良好线性关系,仪器检出限为0.002~0.01μg/L,方法检出限为0.1~0.6μg/kg,加标回收率为94.5%~116%,相对标准偏差为2.02%~14.21%。[结论]该方法质谱图简单,选择性和灵敏度好,定量准确,

  20. Digestibilidade da matéria seca de silagens de milho e de suplementos concentrados determinada por procedimentos in vitro Dry matter digestibility of corn silages and concentrates determined by in vitro procedures

    Directory of Open Access Journals (Sweden)

    F.C.F. Lopes

    2010-10-01

    Full Text Available Compararam-se os valores de digestibilidade in vitro da matéria seca (DIVMS de quatro silagens de milho e de seis concentrados (três proteicos e três energéticos, determinados pelo método de dois estádios realizados em tubos individuais ou em equipamento automatizado de fermentação, e avaliou-se a ocorrência de efeito associativo na digestão de alimentos destas três classes incubadas em um mesmo jarro de fermentação da incubadora in vitro, ou em jarros diferentes contendo a mesma classe de alimentos. Utilizou-se delineamento inteiramente ao acaso, em esquema fatorial 3 x 3 (procedimentos in vitro x classes de alimentos. Os valores de DIVMS determinados pelo método dos tubos foram mais próximos dos relatados na literatura e menores (P0,05 nos valores de DIVMS dos concentrados e das silagens de milho incubados no mesmo jarro de fermentação da incubadora ou, separadamente por alimento, em jarros diferentes.The values of in vitro dry matter digestibility (IVDMD of four corn silages and six concentrates (three proteic and three energetics were determined by the two-stage technique that utilizes individual digestion tubes and by an automatic equipment of fermentation (filter bag technique. It was also evaluated the associative effect on digestion of these three food classes when incubated in the same fermentation jar of the "in vitro incubator" and when in different vessels containing the same class of foods. The experimental design was completely randomized in a 3 x 3 factorial arrangement (in vitro procedures x food classes. The IVDMD values determined in tubes were closer to those found in the literature and lower (P0.05 in IVDMD of concentrates and silages when incubated together in the same fermentation jar or separated by food classes in separated jars.

  1. Microwave-Accelerated Organic Reactions

    Institute of Scientific and Technical Information of China (English)

    LU; TaJung

    2001-01-01

    The use of microwave technology in accelerating organic reactions has received intense attention leading to immense growth recently. Accordingly, we have been interested in improving the efficacy of organic processes by microwave irradiation. Here we report our results on the microwave assisted 1,3-dipolar cycloaddition reaction of nitrile oxides with allylic alcohols, the cleavage reaction of 1,3-diketones under alkaline conditions, and the formation of carbamates from isocyanates with alcohols. The reactions carried out under microwave irradiation, in general, required considerably less reaction time and afforded the desired products in higher yields than those under classical conditions. In all the cases we have studied, the procedures are simplified, the purity of the products are higher, and the cost of reaction is greatly reduced employing microwave.  ……

  2. Microwave-Accelerated Organic Reactions

    Institute of Scientific and Technical Information of China (English)

    LU TaJung

    2001-01-01

    @@ The use of microwave technology in accelerating organic reactions has received intense attention leading to immense growth recently. Accordingly, we have been interested in improving the efficacy of organic processes by microwave irradiation. Here we report our results on the microwave assisted 1,3-dipolar cycloaddition reaction of nitrile oxides with allylic alcohols, the cleavage reaction of 1,3-diketones under alkaline conditions, and the formation of carbamates from isocyanates with alcohols. The reactions carried out under microwave irradiation, in general, required considerably less reaction time and afforded the desired products in higher yields than those under classical conditions. In all the cases we have studied, the procedures are simplified, the purity of the products are higher, and the cost of reaction is greatly reduced employing microwave.

  3. Simultaneous determination of cobalt and nickel in alloy steel by microwave digestion-dual wavelength equal absorption spectrophotometry%微波消解-双波长等吸收分光光度法同时测定合金钢中钴和镍

    Institute of Scientific and Technical Information of China (English)

    李丽华; 张金生; 尹学博; 高昌录

    2001-01-01

    研究并确定了微波消解合金钢的最佳条件,应用双波长等吸收方法解决了PAR-Co2+,Ni2+体系中Co2+,Ni2+同时测定问题。测定了标准合成样品中的Co2+和Ni2+,其回收率分别在98.2%~103.6%和97.9%~103.7%之间。对多种合金钢样品中Co2+和Ni2+进行测定,钴和镍的相对标准偏差分别≤1.00%和≤1.10%;相对误差分别≤±2.5%和≤±2.0%,均优于常压消解合金钢样品所得结果。采用本法测定合金钢中钴和镍,快速、准确、样品损失少、酸用量少,并大大降低环境污染。%In this paper, alloy steel samples are digested in the sealed vessel by the microwave digestion system. The optimum parameters for microwave digestion are studied and selected. Cobalt and nickel in the colored system of Co2+ and Ni2+ 4-(2-pyridylazo) resorcinol (PAR) can be determined simultaneously by dual-wavelength equal absorption spectrophotometry. The recoveries of Co2+ and Ni2+ in synthetic samples are within 98.2%-103.6% and within 97.9%-103.7%, respectively. The relative standard deviations of analytical results in alloy steel are less than 1.00% for Co2+ and less than 1.10% for Ni2+, and relative errors are less than ±2.5% for Co2+ and less than ±2.0% for Ni2+. These results are all less than those of digestion in atmosphere. The experimental results show that the method is rapid, precise, and less contaminative.

  4. Comparison of different procedures to stabilize biogas formation after process failure in a thermophilic waste digestion system: influence of aggregate formation on process stability.

    Science.gov (United States)

    Kleyböcker, A; Liebrich, M; Kasina, M; Kraume, M; Wittmaier, M; Würdemann, H

    2012-06-01

    Following a process failure in a full-scale biogas reactor, different counter measures were undertaken to stabilize the process of biogas formation, including the reduction of the organic loading rate, the addition of sodium hydroxide (NaOH), and the introduction of calcium oxide (CaO). Corresponding to the results of the process recovery in the full-scale digester, laboratory experiments showed that CaO was more capable of stabilizing the process than NaOH. While both additives were able to raise the pH to a neutral milieu (pH>7.0), the formation of aggregates was observed particularly when CaO was used as the additive. Scanning electron microscopy investigations revealed calcium phosphate compounds in the core of the aggregates. Phosphate seemed to be released by phosphorus-accumulating organisms, when volatile fatty acids accumulated. The calcium, which was charged by the CaO addition, formed insoluble salts with long chain fatty acids, and caused the precipitation of calcium phosphate compounds. These aggregates were surrounded by a white layer of carbon rich organic matter, probably consisting of volatile fatty acids. Thus, during the process recovery with CaO, the decrease in the amount of accumulated acids in the liquid phase was likely enabled by (1) the formation of insoluble calcium salts with long chain fatty acids, (2) the adsorption of volatile fatty acids by the precipitates, (3) the acid uptake by phosphorus-accumulating organisms and (4) the degradation of volatile fatty acids in the aggregates. Furthermore, this mechanism enabled a stable process performance after re-activation of biogas production. In contrast, during the counter measure with NaOH aggregate formation was only minor resulting in a rapid process failure subsequent the increase of the organic loading rate.

  5. 微波辅助消解 ICP-MS 测定香菜根、茎、叶中8种微量元素%Determination of 8 Trace EIements in Coriander by Microwave Digestion and ICP-MS

    Institute of Scientific and Technical Information of China (English)

    邢志霞

    2015-01-01

    Objective:To establish a method for simultaneous analysis of Fe,Mn,Zn,Mg,Ca,Cd, Cu,Pb in coriander by microwave digestion and ICP-MS.Methods:With Ge,In,Bi,Sc as internal standard elements,the sample solution is analyzed by ICP-MS after microwave digestion,and the content of elements is calculated.Results:The correlation coefficient of calibration curves is over 0.9997,the recovery rates are 98.2% ~ 102.3% in leaf,98.1% ~ 105.7% in root and 97.8% ~103.7% in stem,and its RSDs are all lower than 3%.Conclusion:The method is sensitive,reliable, stable,rapid,which is feasible to quality management in coriander.%目的:采用微波消解-电感耦合等离子体质谱法测定香菜根、茎、叶中 Fe,Mn,Zn,Mg,Ca,Cd,Cu, Pb 8种元素含量。方法:样品微波消解,选择 Ge,In,Bi,Sc 为内标元素,采用 ICM-MS 测定上述元素。结果:8种元素相关系数 r>0.9997,叶回收率98.2%~102.3%,根回收率98.1%~105.7%,茎回收率97.8%~103.7%,RSD 值均<3%。结论:该方法灵敏、可靠、稳定、快捷,可用于香菜的质量控制。

  6. Determination of Trace Cadmium in Food Packaging Paper Materials by Graphite Furnace Atomic Absorption Spectrometry with Microwave Digestion%微波消解-石墨炉原子吸收光谱法测定纸质食品包装材料中的痕量镉

    Institute of Scientific and Technical Information of China (English)

    苏淑坛; 卫佳欢; 蒋小良; 黄钧

    2013-01-01

    A method for the determination of trace amount of cadmium in food packaging paper materials by graphite furnace atomic absorption spectrometry with microwave digestion was developed.The samples were digested by microwave and the optimal instrument conditions were established by nickel nitrate as matrix modifier.Concentration of cadmium was linear with peak area in the range of 0-10 μ g/L with regression coefficient of 0.999 7.The detection limit of cadmium was 0.025 μ g / L.The method was used in the determination of trace cadmium in food packaging paper materials,the recoveries ranged from 96.0% to 105.5% with relative standard deviation not more than 4.4 %(n=10).%建立了微波消解-石墨炉原子吸收光谱法测定纸质食品包装材料中痕量镉的检验方法.样品经微波消解后,以硝酸镍为基体改进剂,试验确定了石墨炉原子吸收法测定镉的最佳仪器条件.镉的质量浓度在0~10 μg/L与吸收峰面积呈良好的线性关系,线性相关系数r=0.9997,检出限为0.025μg/L.将该法用于纸质食品包装材料中痕量镉的测定,并进行加标回收试验,回收率为96.0%~105.5%,相对标准偏差不大于4.4%(n=10).

  7. Microwave-assisted Extraction of Rutin and Quercetin from Flos Sophorae

    Institute of Scientific and Technical Information of China (English)

    LI Min-jing; YOU Jing-yan; YAO Shuang; DING Lan; LIU Zhong-ying; ZHANG Han-qi

    2004-01-01

    Three microwave-assisted extraction(MAE) procedures were studied. The first procedure was household microwave oven dynamic extraction(HMODE). The second procedure was special microwave oven bath extraction(SMOBE). The third procedure was microwave resonant cavity dynamic extraction(MRCDE). The results obtained by the three microwave-assisted extraction procedures were compared with those obtained by using traditional Soxhlet extraction. The results indicate that the MAE not only took a shorter time, but also simplified the procedure, and made the extraction a higher yield. At the same time the results obtained by the three MAE procedures were also compared with each other.

  8. Microwave Measurements

    CERN Document Server

    Skinner, A D

    2007-01-01

    The IET has organised training courses on microwave measurements since 1983, at which experts have lectured on modern developments. Their lecture notes were first published in book form in 1985 and then again in 1989, and they have proved popular for many years with a readership beyond those who attended the courses. The purpose of this third edition of the lecture notes is to bring the latest techniques in microwave measurements to this wider audience. The book begins with a survey of the theory of current microwave circuits and continues with a description of the techniques for the measureme

  9. Microwave photonics

    CERN Document Server

    Lee, Chi H

    2006-01-01

    Wireless, optical, and electronic networks continue to converge, prompting heavy research into the interface between microwave electronics, ultrafast optics, and photonic technologies. New developments arrive nearly as fast as the photons under investigation, and their commercial impact depends on the ability to stay abreast of new findings, techniques, and technologies. Presenting a broad yet in-depth survey, Microwave Photonics examines the major advances that are affecting new applications in this rapidly expanding field.This book reviews important achievements made in microwave photonics o

  10. Intensified Microwave-Assisted N-Acylation Procedure - Synthesis and Activity Evaluation of TRPC3 Channel Agonists with a 1,3-Dihydro-2H-benzo[d]imidazol-2-one Core.

    Science.gov (United States)

    de la Cruz, Gema Guedes; Svobodova, Barbora; Lichtenegger, Michaela; Tiapko, Oleksandra; Groschner, Klaus; Glasnov, Toma

    2017-04-01

    Upon controlled microwave heating and using cyanuric chloride as a coupling reagent, an efficient amidation procedure for the synthesis of 1,3-dihydro-2H-benzo[d]imidazol-2-one-based agonists of TRPC3/6 ion channels has been developed. Compared to the few conventional protocols, a drastic reduction in processing time from ca. 2 days down to 10 minutes was achieved accompanied by significantly improved product yields. The robustness of the method was confirmed by 18 additional examples including aromatic, aliphatic, and heterocyclic amines and acids. The obtained agonists were screened for biological activity at 1 μM concentration and few structure-activity relations have been established.

  11. Intensified Microwave-Assisted N-Acylation Procedure – Synthesis and Activity Evaluation of TRPC3 Channel Agonists with a 1,3-Dihydro-2H-benzo[d]imidazol-2-one Core

    Science.gov (United States)

    de la Cruz, Gema Guedes; Svobodova, Barbora; Lichtenegger, Michaela; Tiapko, Oleksandra; Groschner, Klaus; Glasnov, Toma

    2017-01-01

    Upon controlled microwave heating and using cyanuric chloride as a coupling reagent, an efficient amidation procedure for the synthesis of 1,3-dihydro-2H-benzo[d]imidazol-2-one-based agonists of TRPC3/6 ion channels has been developed. Compared to the few conventional protocols, a drastic reduction in processing time from ca. 2 days down to 10 minutes was achieved accompanied by significantly improved product yields. The robustness of the method was confirmed by 18 additional examples including aromatic, aliphatic, and heterocyclic amines and acids. The obtained agonists were screened for biological activity at 1 μM concentration and few structure–activity relations have been established. PMID:28413263

  12. Microwave generator

    Science.gov (United States)

    Kwan, T.J.T.; Snell, C.M.

    1987-03-31

    A microwave generator is provided for generating microwaves substantially from virtual cathode oscillation. Electrons are emitted from a cathode and accelerated to an anode which is spaced apart from the cathode. The anode has an annular slit there through effective to form the virtual cathode. The anode is at least one range thickness relative to electrons reflecting from the virtual cathode. A magnet is provided to produce an optimum magnetic field having the field strength effective to form an annular beam from the emitted electrons in substantial alignment with the annular anode slit. The magnetic field, however, does permit the reflected electrons to axially diverge from the annular beam. The reflected electrons are absorbed by the anode in returning to the real cathode, such that substantially no reflexing electrons occur. The resulting microwaves are produced with a single dominant mode and are substantially monochromatic relative to conventional virtual cathode microwave generators. 6 figs.

  13. Continuous determination of lead, cadmium and nickel in imitation jewelries by flame atomic absorption spectrometry with microwave-assisted digestion%微波消解-原子吸收光谱法连续测定仿真饰品中铅镉镍含量

    Institute of Scientific and Technical Information of China (English)

    黄宗平; 黄丽; 蓝光琳; 林伟靖; 赖添岳; 董清木; 王鸿辉

    2012-01-01

    采用HNO3-HF-HC1酸体系消解样品,火焰原子吸收光谱法连续测定非金属材质仿真饰品中的铅、镉和镍.优化了仪器工作参数和消解条件,进行了共存离子的干扰试验.方法检出限分别为铅5.7 mg/kg、镉0.3 mg/kg、镍3.5 mg/kg.实际样品测定的相对标准偏差(n=6)为1.6% ~ 5.2%,回收率为86.0%~105.8%.%Continuous determination of trace amounts of lead, cadmium and nickel in nonmetal materials of imitation jewelries was developed by FAAS with microwave assisted HNO3-HF-HCl digestion. The working parameters and digestive conditions were optimized. The effects of concomitant ions and precisions were studied. The method detection limits were 5.7, 0. 3 and 3. 5 mg/kg for Pb, Cd and Ni, respectively. The practical samples were determined, the RSDs were 1. 6% ~ 5. 2% ( n = 6) , and the recoveries of the above elements ranged from 86. 0% to 105. 8%.

  14. Microwave photonics

    CERN Document Server

    Lee, Chi H

    2013-01-01

    Microwave photonics continues to see rapid growth. The integration of optical fiber and wireless networks has become a commercial reality and is becoming increasingly pervasive. Such hybrid technology will lead to many innovative applications, including backhaul solutions for mobile networks and ultrabroadband wireless networks that can provide users with very high bandwidth services. Microwave Photonics, Second Edition systematically introduces important technologies and applications in this emerging field. It also reviews recent advances in micro- and millimeter-wavelength and terahertz-freq

  15. 微波消解-高分辨连续光源原子吸收光谱法测定锁阳和韭菜籽中的重金属元素含量%Determination of Heavy Metal Elements in Cynomorium and Leek Seeds by High Resolution Continuum Source Atomic Absorption Spectrometry with Microwave Digestion

    Institute of Scientific and Technical Information of China (English)

    胡玥; 丁玉竹; 高旭东; 李西波; 邵士俊

    2016-01-01

    The contents of heavy metals ( Cu, Pb, Cd, Cr, As, Hg) in Chinese herbal medicines ( cynomorium and leek seeds) were tested using microwave digestion-high resolution continuum source atomic absorption spectrometry ( HR-CS AAS) . The samples were digested by microwave digestion, and methods were developed for the determination of the contents of Cu by flame atomic absorption spectrometry, Pb, Cd and Cr by graphite furnace atomic absorption spectrometry, As and Hg by hydride generation atomic absorption spectrometry, respectively. The recoveries were 95. 61% ~100. 1%, the relative standard deviations ( RSDs) were 0. 8% ~3. 3%, and the correlation coefficients of R2 were 0. 999. The results showed that the contents of the above-mentioned heavy metal elements in cynomorium and leek seeds were all lower than the permitted values in the standard of “medicinal plants and preparation of green import industry standard” and National food safety standard “limited quantity of pollutants in food”. The established method are simple, rapid, accurate and reliable, and are successfully applied to analyze the contents of heavy metal elements in Chinese herbal medicines.%利用微波消解-高分辨连续光源原子吸收光谱法测定锁阳、韭菜籽两种中药材中铜( Cu)、铅( Pb)、镉( Cd)、铬( Cr)、砷( As)和汞( Hg)的含量.采用微波消解进行样品前处理,火焰原子吸收法测定其中的Cu含量,石墨炉原子吸收法测定Pb、Cd和Cr含量,氢化物发生原子吸收法测定As、Hg含量.方法线性关系良好,相关系数R2大于0.999,加标回收率为95.61%~100.1%,RSD为0.8%~3.3%,测得锁阳和韭菜籽中Cu、Pb、Cd、Cr、As和Hg的含量值均低于《药用植物及制剂进口绿色行业标准》和食品安全国家标准《食品中污染物限量》( GB2762-2012)中规定的限量指标.方法分析速率快、干扰少、精密度高,适用于中药材中重金属含量的测定.

  16. Anaerobic Digestion.

    Science.gov (United States)

    Liebetrau, Jan; Sträuber, Heike; Kretzschmar, Jörg; Denysenko, Velina; Nelles, Michael

    2017-04-09

    The term anaerobic digestion usually refers to the microbial conversion of organic material to biogas, which mainly consists of methane and carbon dioxide. The technical application of the naturally-occurring process is used to provide a renewable energy carrier and - as the substrate is often waste material - to reduce the organic matter content of the substrate prior to disposal.Applications can be found in sewage sludge treatment, the treatment of industrial and municipal solid wastes and wastewaters (including landfill gas utilization), and the conversion of agricultural residues and energy crops.For biorefinery concepts, the anaerobic digestion (AD) process is, on the one hand, an option to treat organic residues from other production processes. Concomitant effects are the reduction of organic carbon within the treated substance, the conversion of nitrogen and sulfur components, and the production of an energy-rich gas - the biogas. On the other hand, the multistep conversion of complex organic material offers the possibility of interrupting the conversion chain and locking out intermediates for utilization as basic material within the chemical industry.

  17. 微波消解-双浊点萃取 ICP -MS 测定地球化学样品中的痕量铂钯钌铑%Determination of Pt,Pd,Ru,Rh in Geochemical Samples by ICP-MS with Microwave Digestion and Dual-cloud Point Extraction

    Institute of Scientific and Technical Information of China (English)

    沈宇; 张尼; 高小红; 李展; 李日升; 郑建斌

    2016-01-01

    Traditional cloud point extraction methods commonly enrich elements in the viscous surfactant. However,the viscosity of the solution will adversely affect the detection signal of the plasma.Harmful agents such as methanol are usually adopted as a thinner to reduce the viscosity of the organic phase,but the organic component affects the stability of the plasma,and organic absorption on the injection tube will enhance elemental memory effect.These disadvantages limit the widespread application of Inductively Coupled Plasma-Mass Spectrometry (ICP-MS)in cloud point extraction.A method to determine Pt,Pd,Ru, Rh in geochemical samples by ICP-MS based dual-cloud point extraction has been established,and is reported in this paper.After the microwave digestion procedure,first cloud point extraction is performed on the sample solution using DDTP as the sequestrant and Triton X-114 as the surfactant.HNO3 is added into the organic phase,and second cloud point extraction is performed by heating so that Pt,Pd,Ru,Rh enter the water phase from the organic phase. Enrichment factors are 45,33,18,35,and detection limits are 0.05,0.02,0.10 and 0.03 μg/L for Pt,Pd,Ru and Rh,respectively.The proposed method succeeds in the simultaneous enrichment of trace platinum group elements in complex matrix geochemical samples,improving the stability of the ICP-MS measurement.%传统浊点萃取技术是将待测元素富集在黏稠的表面活性剂相中,溶液的黏度会对等离子体检测信号产生影响,通常使用甲醇作为稀释剂降低有机相黏度,有机成分也对等离子体的稳定性产生影响,同时有机物在进样管路上的吸附还会提高待测元素的记忆效应,因而限制了 ICP -MS 在浊点萃取中的应用。本文建立了双浊点萃取技术 ICP -MS 测定地球化学样品中铂钯钌铑的分析方法。样品用微波消解处理后,以DDTP 为螯合剂,Triton X -114为表面活性剂,对消解溶液第一次浊点萃取

  18. The As removal from arsenopyrite-bearing mine waste by microwave

    Science.gov (United States)

    Kim, Hyun Soo; Myung, Eun Ji; Hack Lim, Dae; Kim, Bong Ju; Park, Cheon Young

    2016-04-01

    Penalties incurred by miners for arsenic in concentrates have increased significantly because the removal and disposal of arsenic is difficult and costly for smelters and because the environmental challenges are increasing worldwide. Typically miners incur penalties on arsenic in concentrates above 0.2% As with smelter rejection limits of 0.5%. Therefore, finding an effective solution for removing As during primary mining activities is necessary to avoid penalty. The aim of this study was to investigate the As removal from mine waste using microwave process. The mine waste samples were characterized by chemical and XRD analysis. To determine of As removal from the microwave experiments, aqua regia digestion was performed according to Korean environmental standard method(KESM) and the As removal effect were evaluated using the standard EPA toxicity characteristic leaching procedure(TCLP, EPA 1311 method). The result of mineralogical character for mine waste using XRD was detected arsenopyrite, pyrite, chalcopyrite, pyrrhotite and quartz. The chemical analysis of As, Pb, Zn contents in the mine waste measured 13,896.0, 896.1 and 1,054.6 mg/kg, respectively. The As removal of experiments was conducted to examine the effects of microwave exposure time(1~15min). The results showed that the As removal in mine waste (exposure time = 10min) was 92.90%, and the temperature of mine waste by microwave heating was 886℃. The TCLP leaching of treated mine waste by microwave measured values were below the EPA's current regulatory threshold(As, Pb, Zn : 5 mg/L). The optimum condition of microwave exposure for As removal from arsenopyrite-bearing mine waste was obtained at 800W, 2450MHz, 10min. Acknowledgment : This work was supported by the Energy and Resources Engineering Program Grant funded by the Ministry of Trade, Industry and Energy, Korea

  19. Robust regulation of anaerobic digestion processes.

    Science.gov (United States)

    Mailleret, L; Bernard, O; Steyer, J P

    2003-01-01

    This paper deals with the problem of controlling anaerobic digestion processes. A two-step (i.e. acidogenesis-methanization) mass balance model is considered for a 1 m3 fixed bed digester treating industrial wine distillery wastewater. The control law aims at regulating the organic pollution level while avoiding washout of biomass. To this end, a simple output feedback controller is considered which regulates a variable strongly related to the Chemical Oxygen Demand (COD). Numerical simulations assuming noisy measurements first illustrate the robustness of this control procedure. Then, the regulating procedure is implemented on the considered anaerobic digestion process in order to validate and demonstrate its efficiency in real life experiments.

  20. An appraisal of conventional, microwave and ultrasound BCR extraction methods for the analysis of metals in sediments of Pančevo, Serbia

    Directory of Open Access Journals (Sweden)

    Relić D.

    2013-04-01

    Full Text Available We use conventional, microwave and ultrasound assisted sequential extraction, of defined time and power, techniques for extractions of Cd, Cu, Cr, Ni, Pb and Zn in sediments and certified material. We did not change the conditions of extractions through steps, cause we what to see is there difference in extraction results for the certified material and sediments. We use lower powers and time from microwave and ultrasound extraction in order to avoid additional heating and boiling of the samples. Steps 1–3 of the BCR (Community Bureau of Reference, excluding the hydrogen peroxide digestion in step 3, were completed in 16 h in the conventional, in 120 s with 90 W power of microwave and in 30 min of 42 kHz of an ultrasonic frequency. Digestion of organic matter with hydrogen peroxide was performed the same for all techniques. The fourth step, the pseudo-total content, was performed the same on samples remaining after performing the extraction of the previous three phases either conventionally, microwave-assisted or with ultrasound. The precision and accuracy of the proposed procedures were evaluated using a certified reference material BCR701. Acceptable accuracy for most of the metals was observed for all three steps of BCR protocol applying a 16 h total shaking period. Metals were determined with an acceptable accuracy after the pseudo-total step; expect Cr. Results obtained after the application of different techniques on sediments were comparable with ANOVA test for the 95 % of confidence level.

  1. Industrial scale microwave processing of tomato juice using a novel continuous microwave system.

    Science.gov (United States)

    Stratakos, Alexandros Ch; Delgado-Pando, Gonzalo; Linton, Mark; Patterson, Margaret F; Koidis, Anastasios

    2016-01-01

    This study evaluated the effect of an industrial scale continuous flow microwave volumetric heating system in comparison to conventional commercial scale pasteurisation for the processing of tomato juice in terms of physicochemical properties, microbial characteristics and antioxidant capacity. The effect against oxidative stress in Caco-2 cells, after in vitro digestion was also investigated. Physicochemical and colour characteristics of juices were very similar between technologies and during storage. Both conventional and microwave pasteurisation inactivated microorganisms and kept them in low levels throughout storage. ABTS[Symbol: see text](+) values, but not ORAC, were higher for the microwave pasteurised juice at day 0 however no significant differences between juices were observed during storage. Juice processed with the microwave system showed an increased cytoprotective effect against H2O2 induced oxidation in Caco-2 cells. Organoleptic analysis revealed that the two tomato juices were very similar. The continuous microwave volumetric heating system appears to be a viable alternative to conventional pasteurisation.

  2. Application of Microwave Irradiation to Rapid Organic Inclusion Complex

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ Microwave irradiation has been used in chemical laboratories for moisture analysis and wet asking procedures of biological and geological materials for a number of years [1]. More recently the microwave irradiation also widely used for rapid organic synthesis [2]. However, there have not yet been any reports concerning the ultilisatioin of microwave ovens in the routine organic inclusion complex regularly in chemical research.

  3. Ordered mesoporous silica: microwave synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Fantini, M.C.A. [IF-USP, CP 66318, 05315-970, Sao Paulo, SP (Brazil)]. E-mail: mfantini@if.usp.br; Matos, J.R. [IQ-USP, CP 26077, 05599-970, Sao Paulo, SP (Brazil); Silva, L.C. Cides da [IQ-USP, CP 26077, 05599-970, Sao Paulo, SP (Brazil); Mercuri, L.P. [IQSC-USP, CP 780, 13560-970, Sao Carlos, SP (Brazil); Chiereci, G.O. [IQSC-USP, CP 780, 13560-970, Sao Carlos, SP (Brazil); Celer, E.B. [Department of Chemistry, Kent State University, Kent, OH 44240 (United States); Jaroniec, M. [Department of Chemistry, Kent State University, Kent, OH 44240 (United States)

    2004-09-25

    Ordered mesoporous silicas, FDU-1, synthesized by using triblock copolymer, EO{sub 39}BO{sub 47}EO{sub 39}, as template were hydrothermally treated in a microwave oven at 373 K for different periods of time. The structural and morphological properties of these silicas were investigated by X-ray diffraction and nitrogen adsorption and compared with those for the FDU-1 samples prepared by conventional hydrothermal treatment at 373 K. All samples were calcined at 813 K in N{sub 2} and air. This procedure succeeded in producing ordered cage-like mesoporous structures even after 15 min of the microwave treatment. The best sample was obtained after 60 min of the microwave treatment, which is reflected by narrow pore size distribution, uniform pore size entrances and thick mesopore walls. Longer time of the microwave treatment increased nonuniformity of the pore entrance sizes as evidenced by changes in the hysteresis loops of nitrogen adsorption isotherms.

  4. Extraction of Dihydroquercetin from Larix gmelinii with Ultrasound-Assisted and Microwave-Assisted Alternant Digestion

    Directory of Open Access Journals (Sweden)

    Yuangang Zu

    2012-07-01

    Full Text Available An ultrasound and microwave assisted alternant extraction method (UMAE was applied for extracting dihydroquercetin (DHQ from Larix gmelinii wood. This investigation was conducted using 60% ethanol as solvent, 1:12 solid to liquid ratio, and 3 h soaking time. The optimum treatment time was ultrasound 40 min, microwave 20 min, respectively, and the extraction was performed once. Under the optimized conditions, satisfactory extraction yield of the target analyte was obtained. Relative to ultrasound-assisted or microwave-assisted method, the proposed approach provides higher extraction yield. The effect of DHQ of different concentrations and synthetic antioxidants on oxidative stability in soy bean oil stored for 20 days at different temperatures (25 °C and 60 °C was compared. DHQ was more effective in restraining soy bean oil oxidation, and a dose-response relationship was observed. The antioxidant activity of DHQ was a little stronger than that of BHA and BHT. Soy bean oil supplemented with 0.08 mg/g DHQ exhibited favorable antioxidant effects and is preferable for effectively avoiding oxidation. The L. gmelinii wood samples before and after extraction were characterized by scanning electron microscopy. The results showed that the UMAE method is a simple and efficient technique for sample preparation.

  5. Engineering Digestion: Multiscale Processes of Food Digestion.

    Science.gov (United States)

    Bornhorst, Gail M; Gouseti, Ourania; Wickham, Martin S J; Bakalis, Serafim

    2016-03-01

    Food digestion is a complex, multiscale process that has recently become of interest to the food industry due to the developing links between food and health or disease. Food digestion can be studied by using either in vitro or in vivo models, each having certain advantages or disadvantages. The recent interest in food digestion has resulted in a large number of studies in this area, yet few have provided an in-depth, quantitative description of digestion processes. To provide a framework to develop these quantitative comparisons, a summary is given here between digestion processes and parallel unit operations in the food and chemical industry. Characterization parameters and phenomena are suggested for each step of digestion. In addition to the quantitative characterization of digestion processes, the multiscale aspect of digestion must also be considered. In both food systems and the gastrointestinal tract, multiple length scales are involved in food breakdown, mixing, absorption. These different length scales influence digestion processes independently as well as through interrelated mechanisms. To facilitate optimized development of functional food products, a multiscale, engineering approach may be taken to describe food digestion processes. A framework for this approach is described in this review, as well as examples that demonstrate the importance of process characterization as well as the multiple, interrelated length scales in the digestion process. © 2016 Institute of Food Technologists®

  6. Simultaneous Determination of 7 Trace Elements in Meat and Meat Products by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) with Microwave Digestion%微波消解-电感耦合等离子体质谱法同时测定肉及肉制品中7种痕量元素

    Institute of Scientific and Technical Information of China (English)

    吴春敏; 夏静; 李强; 张岩

    2015-01-01

    A method for the simultaneous determination of 7 trace elements (lead, arsenic, cadmium, chromium, selenium, mercury, and nickel) in meat and meat products by inductively coupled plasma mass spectrometry (ICP-MS) with microwave digestion was established. Samples were pretreated by microwave digestion and determined by ICP-MS with rhodium (Rh) as the internal standard. The microwave digestion conditions and the instrumental parameters were optimized. It was found that the instrumental signal drift and matrix effect could be overcome by using the internal standard method. The developed standard curve was linear in the range of 0 to 20 ng/mL, with a correlation coefficient of more than 0.999. The recoveries of the analytes in spiked samples ranged from 89.4% to 98.9% and the precision expressed as relative standard deviation was less than 5%. The limits of detection for the trace elements were all lower than those stipulated in the Chinese national standards. The proposed method was rapid, accurate, reliable, sensitive and suitable for simultaneous multi-element analysis of meat and meat products.%建立采用电感耦合等离子体质谱法对肉及肉制品中铅、砷、镉、铬、硒、汞、镍7种痕量元素同时检测的方法。用微波消解仪对肉及肉制品进行前处理,以铑作为内标,经电感耦合等离子体质谱仪针对7种痕量元素进行测定。优化微波消解条件以及电感耦合等离子体质谱仪器测定条件。结果表明:内标法能克服仪器信号漂移及样品基体效应的影响。标准曲线的线性范围在0~20 ng/mL,回归方程的相关系数均大于0.999,各元素的加标回收率在89.4%~98.9%之间,相对标准偏差小于5%,检出限均低于国标方法中所规定的方法检出限。该方法具有快速、准确、可靠、灵敏度高及多元素同时分析等优点,可以满足批量肉及肉制品中铅、砷、铬、镉、硒、镍、汞检验和测定。

  7. Atmospheric Pressure Microwave Assisted Heterogeneous Catalytic Reactions

    Directory of Open Access Journals (Sweden)

    Farid Chemat

    2007-07-01

    Full Text Available The purpose of the study was to investigate microwave selective heatingphenomena and their impact on heterogeneous chemical reactions. We also present a toolwhich will help microwave chemists to answer to such questions as “My reaction yields90% after 7 days at reflux; is it possible to obtain the same yield after a few minutes undermicrowaves?” and to have an approximation of their reactions when conducted undermicrowaves with different heterogeneous procedures. This model predicting reactionkinetics and yields under microwave heating is based on the Arrhenius equation, inagreement with experimental data and procedures.

  8. Comparative study on conventional, ultrasonication and microwave assisted extraction of γ-oryzanol from rice bran

    National Research Council Canada - National Science Library

    Kumar, Pramod; Yadav, Devbrat; Kumar, Pradyuman; Panesar, Paramjeet Singh; Bunkar, Durga Shankar; Mishra, Diwaker; Chopra, H K

    2016-01-01

    In present study, conventional, ultrasonic and microwave assisted extraction methods were compared with the aim of optimizing best fitting solvent and method, solvent concentration and digestion time for high yield of γ...

  9. Mercury speciation by high-performance liquid chromatography atomic fluorescence spectrometry using an integrated microwave/UV interface. Optimization of a single step procedure for the simultaneous photo-oxidation of mercury species and photo-generation of Hg0

    Science.gov (United States)

    de Quadros, Daiane P. C.; Campanella, Beatrice; Onor, Massimo; Bramanti, Emilia; Borges, Daniel L. G.; D'Ulivo, Alessandro

    2014-11-01

    We described the hyphenation of photo-induced chemical vapor generation with high performance liquid chromatography-atomic fluorescence spectrometry (HPLC-AFS) for the quantification of inorganic mercury, methylmercury (MeHg) and ethylmercury (EtHg). In the developed procedure, formic acid in mobile phase was used for the photodecomposition of organomercury compounds and reduction of Hg2 + to mercury vapor under microwave/ultraviolet (MW/UV) irradiation. We optimized the proposed method studying the influence of several operating parameters, including the type of organic acid and its concentration, MW power, composition of HPLC mobile phase and catalytic action of TiO2 nanoparticles. Under the optimized conditions, the limits of detection were 0.15, 0.15 and 0.35 μg L- 1 for inorganic mercury, MeHg and EtHg, respectively. The developed method was validated by determination of the main analytical figures of merit and applied to the analysis of three certified reference materials. The online interfacing of liquid chromatography with photochemical-vapor generation-atomic fluorescence for mercury determination is simple, environmentally friendly, and represents an attractive alternative to the conventional tetrahydroborate (THB) system.

  10. Microwave-Assisted Rapid Enzymatic Synthesis of Nucleic Acids.

    Science.gov (United States)

    Hari Das, Rakha; Ahirwar, Rajesh; Kumar, Saroj; Nahar, Pradip

    2016-07-02

    Herein we report microwave-induced enhancement of the reactions catalyzed by Escherichia coli DNA polymerase I and avian myeloblastosis virus-reverse transcriptase. The reactions induced by microwaves result in a highly selective synthesis of nucleic acids in 10-50 seconds. In contrast, same reactions failed to give desired reaction products when carried out in the same time periods, but without microwave irradiation. Each of the reactions was carried out for different duration of microwave exposure time to find the optimum reaction time. The products produced by the respective enzyme upon microwave irradiation of the reaction mixtures were identical to that produced by the conventional procedures. As the microwave-assisted reactions are rapid, microwave could be a useful alternative to the conventional and time consuming procedures of enzymatic synthesis of nucleic acids.

  11. Determination of nickel in biological materials after microwave dissolution using inductively coupled plasma atomic emission spectrometry with prior extraction into butan-1-ol.

    Science.gov (United States)

    Vereda Alonso, E; García de Torres, A; Cano Pavón, J M

    1992-07-01

    A sensitive procedure has been developed for the determination of ultratrace amounts of nickel in biological materials by inductively coupled plasma atomic emission spectrometry after extraction of the nickel ion into butan-1-ol by using 1,5-bis(di-2-pyridylmethylene)thiocarbonohydrazide as the extracting reagent. Fast, efficient and complete sample digestion is achieved by an HNO3-HCl poly(tetrafluoroethylene) bomb dissolution technique using microwave heating. Results obtained for eleven certified reference materials agreed with the certified values.

  12. Engineering Digestion: Multiscale Processes of Food Digestion

    OpenAIRE

    Bornhorst, GM; Gouseti, O.; Wickham, MSJ; Bakalis, S.

    2016-01-01

    © 2016 Institute of Food Technologists®. Food digestion is a complex, multiscale process that has recently become of interest to the food industry due to the developing links between food and health or disease. Food digestion can be studied by using either in vitro or in vivo models, each having certain advantages or disadvantages. The recent interest in food digestion has resulted in a large number of studies in this area, yet few have provided an in-depth, quantitative description of digest...

  13. Determination of Trace Elements in Pomegranate Peel and Pomegranate Seed by Inductively Coupled Plasma-Atomic Emission Spectrometry with Microwave Digestion%微波消解-等离子体原子发射光谱法测定石榴皮和石榴籽中微量元素

    Institute of Scientific and Technical Information of China (English)

    吴佳; 解成喜

    2012-01-01

    采用微波消解样品,电感耦合等离子体原子发射光谱法(ICP-AES)测定了石榴皮和石榴籽中K、Ca、Mg、Fe、A1、Cu、Zn、Mn、Na、Li、P、S12种微量元素的含量.在最佳仪器工作条件下,各元素的加标回收率为91.8%~103.1%,相对标准偏差(RSD)为0.70%~2.68%.实验结果可为石榴皮和石榴籽中微量元素与其药效的相关性提供科学依据.%The trace elements of K,Ca,Mg,Fe, Al,Cu,Zn,Mn,Na,Li,P and S in the pomegranate peel and pomegranate seed were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) with microwave digestion. Under the optimal working conditions of the equipment, the element recoveries of standard addition are 91. 8% ~ 103. l%,and the relative standard deviations (RSDs) are 0. 70%~2. 68%.

  14. 利用土壤干燥箱主动干燥-微波消解-原子吸收分光光度法测定土壤中的重金属%Determination of Heavy Metal in Soil through Active Drying of Soil Drying Oven,Microwave Digestion and Atomic Absorption Spectrophotometry

    Institute of Scientific and Technical Information of China (English)

    张健美; 吴春妍; 许卫娟

    2012-01-01

    The heavy metal in a large amount of soil sample could be determined in a short time by drying the soil with M280685 soil drying oven,microwave digestion and atomic absorption spectrophotometry.The qualified rate of the parallel double-sample testing by this method and the quality-controlled samples can both reach the requirements of Technical Specification for Soil Environmental Monitoring(HJ/T166-2004).%利用M280685土壤干燥箱干燥土壤、微波消解、原子吸收分光光度法,在短时间内完成大量土壤样品中重金属的测定。利用该法测定土壤中的重金属平行双样测定合格率,质控样品均能达到土壤环境监测技术规范(HJ/T166-2004)相应的要求。

  15. Anaerobic Digestion: Process

    DEFF Research Database (Denmark)

    Angelidaki, Irini; Batstone, Damien J.

    2011-01-01

    Organic waste may degrade anaerobically in nature as well as in engineered systems. The latter is called anaerobic digestion or biogasification. Anaerobic digestion produces two main outputs: An energy-rich gas called biogas and an effluent. The effluent, which may be a solid as well as liquid...... with very little dry matter may also be called a digest. The digest should not be termed compost unless it specifically has been composted in an aerated step. This chapter describes the basic processes of anaerobic digestion. Chapter 9.5 describes the anaerobic treatment technologies, and Chapter 9.......6 addresses the mass balances and environmental aspects of anaerobic digestion....

  16. Preparation of shrimp waste as aqua feedstuff: a study of physicochemical properties and in vitro digestibility

    Directory of Open Access Journals (Sweden)

    Karun Thongprajukeaw

    2014-12-01

    Full Text Available The effects of different preparation methods (boiling, microwave irradiation, oven-drying, soaking, and sun-drying for improving the protein quality of shrimp waste (SW when used as aqua feedstuff were observed. The findings from this study indicate that microwave irradiation maintained both the chemical composition and total carotenoid concentration of the SW. This method controlled the appropriate physicochemical characteristics thus promoting proteolytic digestion, as indicated by measurement of changes in pH, water solubility, microstructures, and thermal transition. The protein digestibility based on the use of digestive enzymes from Nile tilapia (Oreochromis niloticus also increased after preparation with microwave irradiation. Based on this study, improvement in the protein quality in SW may be achieved by microwave irradiation and this method may be used as an alternative method for preparing aqua feedstuff.

  17. Microwave power engineering applications

    CERN Document Server

    Okress, Ernest C

    2013-01-01

    Microwave Power Engineering, Volume 2: Applications introduces the electronics technology of microwave power and its applications. This technology emphasizes microwave electronics for direct power utilization and transmission purposes. This volume presents the accomplishments with respect to components, systems, and applications and their prevailing limitations in the light of knowledge of the microwave power technology. The applications discussed include the microwave heating and other processes of materials, which utilize the magnetron predominantly. Other applications include microwave ioni

  18. Advances in microwaves 8

    CERN Document Server

    Young, Leo

    2013-01-01

    Advances in Microwaves, Volume 8 covers the developments in the study of microwaves. The book discusses the circuit forms for microwave integrated circuits; the analysis of microstrip transmission lines; and the use of lumped elements in microwave integrated circuits. The text also describes the microwave properties of ferrimagnetic materials, as well as their interaction with electromagnetic waves propagating in bounded waveguiding structures. The integration techniques useful at high frequencies; material technology for microwave integrated circuits; specific requirements on technology for d

  19. ICP-AES Determination of 10 Metal Elements in Nickel Concentrate with Microwave Assisted Sample Digestion%微波消解样品-电感耦合等离子体原子发射光谱法测定镍精矿中10种金属元素

    Institute of Scientific and Technical Information of China (English)

    秦立俊; 王恒; 王雪婷; 王通胜; 姜郁; 夏新媛; 郑光煜; 窦维伟

    2012-01-01

    Ten elements,i.e.,Al,Ca,Co,Cr,Cu,Mn,Mg,Ni,Pb and Zn,in nickel concentrate were determined simultaneously by ICP-AES with microwave assisted sample digestion.0.200 0 g of the sample in a digestion vessel was mixed with 2 mL of HCl,6 mL of HNO3 and 1 mL of HF successively;after covering the vessel tightly,the sample was digested in microwave digestor under the pre-set programe.Analytical spectral lines of 308.215 nm(for Al),317.933 nm(for Ca),228.616 nm(for Co),267.716 nm(for Cr),324.745 nm(for Cu),279.079 nm(for Mg),257.610 nm(for Mn),220.353 nm(for Pb),206.200 nm(for Zn) and 231.604 nm(for Ni) were chosen for the analysis.Matrix effect was compensated by the matching method in preparation of calibration curves.The proposed method was applied to the analysis of a CRM(GBW 07283) and a sample of nickel concentrate.The results of the elements found in the CRM by the present method were in consistency with the certified values,while the results of elements found in the concentrate sample were checked quite well with the results obtained by the GB methods.Values of recovery found were in the range of 95.8%-103.1% with RSD′s(n=6) less than 4.5%.%采用微波消解样品-电感耦合等离子体原子发射光谱法同时测定镍精矿样品中铝、钙、钴、铬、铜、锰、镁、镍、铅、锌等10种金属元素的含量。0.200 0g试样置于消解罐中,先后加入盐酸2mL、硝酸6mL及氢氟酸1mL,密闭罐盖按设定的微波消解程序进行消解。试验选择铝、钙、钴、铬、铜、镁、锰、铅、锌和镍的分析线分别为308.215,317.933,228.616,267.716,324.745,279.079,257.610,220.353,206.200,231.604nm,配制工作曲线时采用基体匹配的方法消除基体干扰。方法用于镍钴矿标准样品(GBW 07283)和镍精矿实际样品的分析,此方法的测定值与认定值及国标方法的测定值相一致。方法的回收率在95.8%~103.1%之间,相对标准偏差(n=6

  20. 人血和尿中锡的高压微波络合消解氢化物发生-原子荧光测定法%Determination of tin in human blood and urine with high-pressure microwave digestion and complexing ligand and hydride generation-atomic fluorescence spectrometry

    Institute of Scientific and Technical Information of China (English)

    陈峰; 谢超

    2013-01-01

    Objective To establish the hydride generation-atomic fluorescence spectrometric method for the determination of tin in human blood and urine with high-pressure microwave digestion and complexing ligand.Methods Human blood and urine samples were digested by using high-pressure microwave.Then complexing ligand 1% EDTA,5 ml 150 g/L thiourea and ascorbic acid were added to mask the interfering ions such as nickel,iron,arsenic,selenium and etc.Tin concentration was determined with hydride-generation atomic fluorescence spectrometric method with sodium borohydride as the reductant in 2% sulphuric acid media.Results The linear range of tin was 10-100 μg/ml,the regression equations and correlation coefficients in blood and urine were y=9.391 1 x-16.312,r=0.999 7,y=8.244 7x-27.849 6,r=0.998 2,respectively.The limits of detection of tin in blood and urine were 0.090,0.020 μg/L respectively.The relative standard derivation of this method was 1.4%-6.1%.The rates of recovery were between 98.1% and 101.8%.Conclusion This method presents many advantages,such as completed sample digestion,rapid,less matrix disturbance,accurate,sensitive and is applicable to the determination of tin in blood and urine in grass-roots units.%目的 建立人血、尿中锡的高压微波络合消解氢化物发生-原子荧光测定法.方法 利用高压微波络合消解已加入1% EDTA溶液的人血和尿液,在样品测定液中加入150 g/L硫脲-抗坏血酸5ml来掩蔽镍、铁、砷、硒等干扰离子;以2%硫酸作为介质,以2%的硼氢化钠溶液作为还原剂,采用氢化物发生-原子荧光法测定锡浓度.结果 在10~100 μg/ml的线性范围内,血中锡所得回归方程为y=9.391 1x-16.312,r=0.999 7;尿中锡所得回归方程为y=8.244 7x-27.849 6,r=0.998 2.血、尿中锡的检出限分别为0.090、0.020 μg/L.该方法的RSD为1.4%~6.1%,回收率在98.1%~101.8%之间.结论 该方法样品消解完全,测定时间短,待测元素

  1. Problems Digesting Dairy Products?

    Science.gov (United States)

    ... Consumers Home For Consumers Consumer Updates Problems Digesting Dairy Products? Share Tweet Linkedin Pin it More sharing ... the natural sugar found in milk and other dairy products. People who cannot digest lactose have a ...

  2. Acceleration of Organic Reactions Using Microwave

    Institute of Scientific and Technical Information of China (English)

    Lu Ta-Jung

    2004-01-01

    The use of microwave technology in accelerating organic reactions has received intense attention leading to immense growth recently. Accordingly, we have been interested in improving the efficacy of organic processes by microwave irradiation. Here we report our results on the microwave assisted direct amide formation from carboxylic acid and amine, the hydrolysis of biopolymers, and nucleophilic aromatic substitution reaction. The reactions carried out under microwave irradiation, in general, required considerably less reaction time and afforded the desired products in higher yields than those under classical conditions. In all the cases we have studied, the procedures are simplified, the purity of the products are higher, and the cost of reaction is greatly reduced employing microwave.

  3. Digestibility of sorghum proteins.

    OpenAIRE

    Axtell, J D; Kirleis, A. W.; Hassen, M M; D'Croz Mason, N; Mertz, E T; Munck, L.

    1981-01-01

    Published information indicates that rice, maize, and wheat proteins are much more digestible in children than sorghum proteins are (66-81% compared with 46%). However, this digestibility difference cannot be demonstrated with the weanling rat, which gave digestibility values of 80% for cooked and 85% for uncooked sorghum gruels. Therefore, a search was made for a laboratory system sensitive to the digestibility differences between sorghum and other cereals. We found that porcine pepsin in vi...

  4. Determination of Anthocyanins in Purple Sweet Potato by Microwave Digestion and Visible Spectrophotometric%微波消解-可见分光光度法测定紫甘薯中花青素

    Institute of Scientific and Technical Information of China (English)

    陈长应

    2016-01-01

    讨论紫甘薯中花青素的微波辅助提取及可见分光光度法定量检测方法。结果表明:在520 nm下测定样品中花青素的吸光度,相对标准偏差为5.26%(n=6),加标平均回收率为97.8%,最低检测浓度为0.835μg/mL。该方法简便准确,可用于紫甘薯中花青素含量的测定。%This article discuses the microwave-assisted extraction of anthocyanin from purple sweet potato and the way to quantitatively detect anthocyanin under visible spectrophotometer measure system. The result demonstrates that the determination of absrbance of anthocyanins in the sample at the 520 nm , the relative standard deviation is 5.26%(n=6), average recovery at the spiked level is 97.8%,the minimum detectable concentration of anthocyanin is 0.835 μg/mL. The present invention provides a quick easy way to quantitatively detect anthocyanin in purple sweet potatoes.

  5. [Digestion-flame atomic absorption spectroscopy].

    Science.gov (United States)

    Xu, Liang; Hu, Jian-Guo; Liu, Rui-Ping; Wang, Zhi-Min; Narenhua

    2008-01-01

    A microwave digestion-flame atomic absorption spectroscopy (FAAS) method was developed for the determination of metal elements Na, Zn, Cu, Fe, Mn, Ca and Mg in Mongolian patents. The instrument parameters for the determination were optimized, and the appropriate digestion solvent was selected. The recovery of the method was between 95.8% and 104.3%, and the RSD was between 1.6% and 4.2%. The accuracy and precision of the method was tested by comparing the values obtained from the determination of the standard sample, bush twigs and leaves (GSV-1) by this method with the reference values of GSV-1. The determination results were found to be basically consistent with the reference values. The microwave digestion technique was applied to process the samples, and the experimental results showed that compared to the traditional wet method, the present method has the merits of simplicity, saving agents, rapidness, and non-polluting. The method was accurate and reliable, and could be used to determine the contents of seven kinds of metal elements in mongolian patents.

  6. 微波消解-电感耦合等离子体发射光谱法测定合质金中的铱%Determination of Ir by microwave digestion-ICP-AES in alloy gold

    Institute of Scientific and Technical Information of China (English)

    孙福红; 侯辉南

    2014-01-01

    建立了铅试金富集-微波消解-电感耦合等离子体原子发射光谱仪测定合质金中铱的分析方法,确定了样品溶解方法和测试条件。该方法精密度和准确度的验证实验结果表明,测定铱的相对标准偏差(RSD)小于4.90%,加入标准物质回收率为97.44%~99.62%,分析结果准确可靠。%The paper established a determination method of Ir in alloy gold by lead assay enrichment-mircowave digestion-ICP-AES and settled sample dissolution method and test conditions.The precision and accuracy verifica-tion results show that RSD is kept below 4 .90%and the recovery rate with addition of standard substance is between 97 .44 %and 99 .62 %.

  7. Anaerobic Digestion: Process

    DEFF Research Database (Denmark)

    Angelidaki, Irini; Batstone, Damien J.

    2011-01-01

    Organic waste may degrade anaerobically in nature as well as in engineered systems. The latter is called anaerobic digestion or biogasification. Anaerobic digestion produces two main outputs: An energy-rich gas called biogas and an effluent. The effluent, which may be a solid as well as liquid...... with very little dry matter may also be called a digest. The digest should not be termed compost unless it specifically has been composted in an aerated step. This chapter describes the basic processes of anaerobic digestion. Chapter 9.5 describes the anaerobic treatment technologies, and Chapter 9...

  8. Analysis of Selenium in Blood of Patients with Lung Cancer by Microwave Digestion-Atomic Fluorescence Spectrometry%微波消解-原子荧光光谱法分析肺癌患者全血中硒

    Institute of Scientific and Technical Information of China (English)

    董琳; 张欣欣; 王继灵; 吴桂平; 杨庆斌

    2014-01-01

    目的:探讨肺癌患者血样中硒含量的变化。方法采集肺癌组和对照组血样,用硝酸、过氧化氢混合液微波消解样品,采用原子荧光光谱法测定血样中硒的含量。结果肺癌组和对照组硒平均质量浓度分别为0.087、0.123 mg/L。结论肺癌患者血样硒含量明显降低,缺硒可能是导致肺癌高发的重要因素。%Objective The paper investigates the change of the selenium content in the blood samples of patients with lung cancer .Methods The writer applies miscible liquids of nitric acid and hydrogen peroxide to the digestion of the collected blood samples from lung cancer group and the control group , using atomic fluorescence spectrometry to determine the content of selenium in blood samples .Results The average content of selenium in the lung cancer group and control group in average content of selenium are 0.087 mg/L and 0.123 mg/L respectively .Conclusion The content of selenium significantly lowered in the blood samples collected from patients with lung cancer .Selenium deficiency may be an important factor leading to high incidence of lung cancer .

  9. Effect of Microwave Modified Bamboo Charcoal Particles on Immune Performance and Digestive Absorption Function of Experimentally Induced Diarrhea Rats%微波改性竹炭颗粒对实验性腹泻大鼠免疫性能和消化吸收功能的影响

    Institute of Scientific and Technical Information of China (English)

    王建辉; 刘永乐; 李赤翎; 刘冬敏; 尹欣欣; 李艳; 王群辉

    2012-01-01

    In order to investigate the effect of bamboo charcoal particles on immune performance and digestive absorption function of experimentally induced diarrhea rata, microwave activated bamboo charcoal particles (MABCP) was added into their diets at 0.05% ,0.10% ,and 0.15% to conduct a 7-day feeding trials. Microwave activation significantly enhanced the specific surface area and adsorption performance of bamboo charcoal panicles. When MABCP were added into the rat diet,diarrhea rate was significantly reduced (P 0.05). Intestinal mitochondrial NADH dedydrogenase,H+-ATPase and succinate dehydrogenase activities were increased ( P < 0. 05) and MDA content was decreased significantly (P < 0.05). The results indicated that MABCP could improve immune performance,enhance the small intestinal absorption function,decrease radical production and maintain/ameliorate cellular oxidative phosphorylation level;the comparatively optimal dietary level of MABCF was 0.05%.%旨以研究活性竹炭颗粒(MABCP)对实验性腹泻大鼠免疫性能和消化吸收功能的影响,在大鼠饲粮中分别添加0.05,0.10,0.15%的经KOH微波活化处理的竹炭颗粒,对模型大鼠进行为期一周的饲养试验.研究发现:经KOH微波活化的竹炭颗粒,比表面积与吸附性能大幅增强,其能显著降低腹泻大鼠稀便率(P<0.05),有效增加胸腺和脾脏指数(P<0.05);显著提高腹泻大鼠血清D-木糖含量(P<0.05),但对消化酶如淀粉酶活性无显著影响(P>0.05);肠道线粒体琥珀酸脱氢酶、NADH脱氢酶、H+-ATP酶活性显著增强(P<0.05),MDA生成量显著降低(P<0.05).试验表明MABCP可提高体积免疫性能,改善小肠吸收功能,减少肠道自由基生成,有效维持或改善细胞氧化磷酸化水平,其中以低剂量添加效果更为明显.

  10. Practical microwave electron devices

    CERN Document Server

    Meurant, Gerard

    2013-01-01

    Practical Microwave Electron Devices provides an understanding of microwave electron devices and their applications. All areas of microwave electron devices are covered. These include microwave solid-state devices, including popular microwave transistors and both passive and active diodes; quantum electron devices; thermionic devices (including relativistic thermionic devices); and ferrimagnetic electron devices. The design of each of these devices is discussed as well as their applications, including oscillation, amplification, switching, modulation, demodulation, and parametric interactions.

  11. Determination of Lead in Tea Garden Soil by Hydride Generation Atomic Fluorescence Spectrometry with Microwave Digestion%微波消解-氢化物发生原子荧光光谱法测定茶园土壤中的铅

    Institute of Scientific and Technical Information of China (English)

    凤海元; 时晓露; 黄勤

    2013-01-01

    样品用王水微波消解浸提,氢化物发生-原子荧光光谱法测定茶园土壤中痕量铅的含量.对样品浸取方法、实验条件、增感剂和共存元素进行了条件实验.结果表明,王水微波消解浸取,铅浸出量最大,减少了试剂用量和环境污染;铁氰化钾-盐酸羟胺体系有显著的增感作用,铁氰化钾在配制溶液时用米糠除去试剂中可能存在的铅,降低了空白;钴、锌、砷、镉等共存离子不干扰铅的测定,通过加入邻菲啰啉-硫氰酸钠消除铁和铜的干扰,提高了铅的回收率.方法检出限为0.65 μg/L,精密度(RSD,n=10)为1.89%,回收率在86.8% ~ 110.4%之间.用土壤标准物质验证,测定值与标准值相符,方法快速准确,适合于大批量样品的分析检测.%The microwave digestion system with aqua regia was developed for the determination of trace lead in tea garden soil using Hydride Generation-Atomic Fluorescence Spectrometry ( HG-AFS). The leaching methods, experimental conditions, booster and coexisting element were optimized. The largest amount of lead was leached out by microwave digestion with aqua regia, which has the advantages of less usage of reagent and less environmental pollution. An appropriate amount of potassium ferricyanide and hydroxylamine hydrochloride improved the hydride generation efficiency of Pb. The lead blank was reduced significantly when Potassium ferricyanide solution was treated with rice husk to remove Pb in the reagent. It was found that Co, Zn, As, and Cd did not interfere with the determination of lead. The addition of 1,10-phenanthroline monohydrate and sodium hydrosulfide could effectively eliminate the interferences from Fe and Cu, which improved the recovery rate of lead. The limit of detection was 0. 65 μg/L and the precision was 1. 89% (n = 10) with recoveries of 86. 8% - 110. 4% for Pb. The reliability of the method has been tested by determination of Pb in the Soils Standard Reference

  12. 微波消解-电感耦合等离子体质谱法快速鉴别巧克力中可可脂来源%Identification of the source of cocoa butter in chocolate by inductively coupled plasma-mass spectrometry with microwave digestion

    Institute of Scientific and Technical Information of China (English)

    宋晓华; 杨丽君; 张玉春; 崔凤杰; 时文春; 李金洺; 张迎康; 梁颖淑

    2016-01-01

    目的:采用微波消解-电感耦合等离子体质谱法(ICP-MS)快速鉴别巧克力中的可可脂来源。方法分别准确称取巧克力和代可可脂巧克力及可可原材料0.5000 g,加入5 mL浓硝酸经微波消解后定容至50 mL,上机检测铜离子含量。结果铜元素在添加水平为0.10、0.15 mg/kg的回收率为90.52%~100.83%,方法精密度1.4%,方法检出限为0.5 mg/kg。巧克力中铜元素含量大小关系:可可固形物50%以上>可可固形物50%以下>代可可脂巧克力。巧克力中可可固形物含量在85%以上铜元素含量和可可固形物和可可粉中的铜元素含量相当。结论通过ICP-MS法快速检测巧克力中的铜元素可以简单便捷地鉴别巧克力中可可脂来源属性。%ABSTRACT:Objective To rapid identification of the source of cocoa butter in chocolate by inductively coupled plasma-mass spectrometry (ICP-MS) with microwave digestion. Methods The chocolate, cocoa butter chocolate and cocoa raw materials were accurately took 0.5000 g, respectively, added 5 mL concentrated nitric acid for microwave digestion and fixed capacity to 50 mL. The content of copper was analyzed. Results The recoveries of the method with the spiked levels of 0.10 and 0.15 mg/kg were 90.52%~100.83%, the relative standard deviation (RSD) was less than 1.4%, and the detection limit was 0.5 mg/kg. The order of content of Cu in chocolate were as follows:cocoa solids above 50%>cocoa solids below 50%>cocoa butter replacers. The content of Cu in chocolate with cocoa solids above 85%was comparable to the Cu content in cocoa solids and cocoa powder. Conclusion The proposed method is feasible to identify the source of cocoa butter in chocolate simply and conveniently.

  13. 微波消解-电感耦合等离子体质谱法快速鉴别巧克力中可可脂来源%Identification of the source of cocoa butter in chocolate by inductively coupled plasma-mass spectrometry with microwave digestion

    Institute of Scientific and Technical Information of China (English)

    宋晓华; 杨丽君; 张玉春; 崔凤杰; 时文春; 李金洺; 张迎康; 梁颖淑

    2016-01-01

    Objective To rapid identification of the source of cocoa butter in chocolate by inductively coupled plasma-mass spectrometry (ICP-MS) with microwave digestion.MethodsThe chocolate, cocoa butter chocolate and cocoa raw materials were accurately took 0.5000 g, respectively, added 5 mL concentrated nitric acid for microwave digestion and fixed capacity to 50 mL. The content of copper was analyzed.Results The recoveries of the method with the spiked levels of 0.10 and 0.15 mg/kg were 90.52%~100.83%, the relative standard deviation (RSD) was less than 1.4%, and the detection limit was 0.5 mg/kg.The order of content of Cu in chocolate were as follows: cocoa solids above 50%> cocoa solids below 50%>cocoa butterreplacers. The content of Cu in chocolate with cocoa solids above85% was comparable to the Cu content in cocoa solids and cocoa powder.ConclusionThe proposed method is feasible to identify the source of cocoa butter in chocolate simply and conveniently.%目的:采用微波消解-电感耦合等离子体质谱法(ICP-MS)快速鉴别巧克力中的可可脂来源。方法分别准确称取巧克力和代可可脂巧克力及可可原材料0.5000 g,加入5 mL浓硝酸经微波消解后定容至50 mL,上机检测铜离子含量。结果铜元素在添加水平为0.10、0.15 mg/kg的回收率为90.52%~100.83%,方法精密度1.4%,方法检出限为0.5 mg/kg。巧克力中铜元素含量大小关系:可可固形物50%以上>可可固形物50%以下>代可可脂巧克力。巧克力中可可固形物含量在85%以上铜元素含量和可可固形物和可可粉中的铜元素含量相当。结论通过ICP-MS法快速检测巧克力中的铜元素可以简单便捷地鉴别巧克力中可可脂来源属性。

  14. 微波消解—碰撞反应池技术电感耦合等离子体质谱法测定食品中的铅%Determination of lead in foods by inductively coupled plasma mass spectrometry based on collided reaction cell technology after microwave digestion

    Institute of Scientific and Technical Information of China (English)

    殷忠; 周彬; 汪思顺

    2013-01-01

    OBJECTIVE To establish a method for determination of lead in foods by inductively coupled plasma mass spectrometry based on collided reaction cell technology after microwave digestion.METHODS After microwave digestion,the samples were directly determined by inductively coupled plasma mass spectrometry based on collided reaction cell technology.Internal standard element of Thallium (204TI) was used to correct matrix interference and signal drifting,high-performance Xs interface was used to reduce non-mass spectrum interferences,and the collided reaction cell technology (CCT mode) was used to eliminate mass spectrum interferences.RESULTS The optimal linear range of the method was 0-40μg/L with a correlation coefficient of 0.999 8.The detection limit of the method,the lowest quantitative limit,the relative standard deviation and the recovery rate were 0.000 5 mg/kg,0.001 7 mg/kg,1.1%-3.8% and 93.3%-104.0%,respectively.CONCLUSION The method is sensitive,accurate,simple and fast.There is no significant difference between the results from the method and graphic furnace atomic absorption spectrometry and is suitable for analysis of lead in foods.%目的 建立食品中铅的微波消解—碰撞反应池技术电感耦合等离子体质谱法.方法 样品经微波消化后直接用碰撞反应池电感技术的耦合等离子体质谱仪(ICP-MS)进行测定.用铊(204TI)内标校正基体干扰和漂移,用高性能Xs接口降低非质谱干扰,用碰撞反应池技术(CCT模式)消除质谱干扰.结果 方法的标准曲线线性范围为0~40μg/L,相关系数为0.999 8.方法检出限为0.000 5mg/kg,最低检出浓度为0.001 7 mg/kg,相对标准偏差为1.1%~3.8%,回收率为93.3%~104.0%.结论 本方法灵敏、准确,操作简便、快速,对样品的测定结果与石墨炉原子吸收光度法之间无显著性差异,能用于食品中铅的准确测定.

  15. 微波消解-碰撞反应池技术电感耦合等离子体质谱法测定食品总砷的方法研究%Methodology research on determination of total arsenic in foods by inductively coupled plasma mass spectrometry based on collided reaction cell technology with microwave digestion

    Institute of Scientific and Technical Information of China (English)

    殷忠

    2013-01-01

    Objective To establish a method for determination of total arsenic in foods by inductively coupled plasma mass spectrometry based on collided reaction cell technology with microwave digestion and provide a new reliable method for accurate quantitative analysis of total arsenic in foods.Methods After microwave digestion,the samples were directly determined by inductively coupled plasma mass spectrometry based on collided reaction cell technology.Internal standard element of Yttrium(89Y) was used to correct matrix interference and signal drifting,high-performance Xs interface was used to reduce non-mass spectrum interferences,and the collided reaction cell technology (CCT mode) was used to eliminate mass spectrum interferences.Meanwhile,arsenic measurement results were compared with the arbitral method.Results The optima 1 linear range of the method standard curve was 0-40 μg/L with a correlation coefficient of 0.9998.The detection limit of the method,the lowest quantitative limit,the relative standard deviation and the recovery rate were 0.0025 mg/kg,0.082 mg/kg,1.5%-4.2% and 95.0%-105.0%,respectively.The detection results of the three standard reference materials were satisfactory.Compared with the arbitral method,there was no obvious difference (P < 0.05).Conclusions The method not only has lower detection limit,but also is simple,fast and more accurate.The results are consistent with those by arbitral method,and the new method is available for accurate quantitative analysis of total arsenic in foods.%目的 建立测定食品总砷的微波消解-碰撞反应池技术电感耦合等离子体质谱法,为食品总砷的准确定量提供新的方法.方法 样品经微波消化后直接用碰撞反应池电感技术的耦合等离子体质谱仪(ICP-MS)进行测定分析.用钇(89Y)内标校正基体干扰和漂移,用高性能Xs接口降低非质谱干扰,用碰撞反应池技术(CCT模式)消除质谱干扰.同时,将砷的测定结果

  16. Determination of Thirty Three Elements in Lung Cancer Tissues of Patients with Lung Cancer by Microwave Digestion-ICP-MS%微波消解-ICP-MS法测定肺癌患者肺组织中33种元素

    Institute of Scientific and Technical Information of China (English)

    张霖琳; 马千里; 黄云超; 吴国平; 魏复盛

    2009-01-01

    A method for determining 33 elements in lung tissues of patients with lung cancer was developed by using vacuum freeze-drying microwave digestion-ICP-MS. The lung tissue samples were treated by vacuum freeze-drying equipment. After mi-crowave digestion in HNO_3-H_2O_2 solution system, the samples were diluted with the method of constant volume. Under the op-timized conditions the samples were analyzed by ICP-MS. The double internal standard elements Rh and Re were used to com-pensate for matrix suppression effect and sensitivity drift. The analytical results showed that the detection limits of the 33 ele-ments were 0. 01-0.45 ng·mL~(-1).The national standard reference material GBW(E)080193 bovine liver was analyzed by the de-scribed method and the measured element values accorded with the standard values or the reference values. The relative standard deviation (RSD) of the method was 2. 1%-14. 3%. The recovery rates of the studied elements were 90. 1%-117. 5%. The con-tents of 33 elements in lung cancer tissues, paracancerous lung tissues and benign lung tissues of 6 patients with lung cancer were determined by the method. It was indicated that the method is rapid, simple and accurate for determining multi-elements in hu-man lung tissue and other biological samples.%建立了冷冻干燥微波消解ICP-MS法测定肺癌患者肺组织中33种元素的方法.样品经真空冷冻干燥,采用纯化硝酸-过氧化氧体系微波消解,稀释定容后用ICP-MS对溶液进行元素的测定,在优化仪器工作参数后,以铑(Rh)和铼(Re)双内标进行校正.测定结果表明,元素榆出限为0.01~0.45 ng·mL~(-1),测定了国家标准物质GBw(E)080193牛肝中的元素,测定值与标准值或参考值一致,元素精密度(RSD)为2.1%~14.3%,回收率为90.1%~117.5%.用该法测定了6例肺癌患者的肿癌、痛旁和正常组织中33种元素的含量.所建立的方法快速、简便、准确,适于肺组织等生物样品中多种元素的测定.

  17. 微波消解-氢化物原子荧光光谱法测定粤东地区海产品中砷的研究%Determination of Arsenic in Seafood by Hydride Generation-atomic Fluorescence Spectrometry Combined with Microwave Oven Digestion

    Institute of Scientific and Technical Information of China (English)

    蔡龙飞; 徐春秀; 张应钦; 邱新红

    2011-01-01

    [目的]建立一种测定海产品中微量砷的有效方法.[方法]采用微波消解-氢化物原子荧光光谱法测定了粤东地区海产品中砷的含量.[结果]砷在1.0~50.0μg/L范围内线性关系良好,相关系数为0.995,方法的检出限为0.02107μg/L,相对标准偏差为0.932%.部分海产品的含砷量超过国家标准,其超标原因可能与沿海地区的工业污染有关.[结论]该方法试剂用量少、污染小、简便、快速、准确,适于各类海产品中砷含量的检测.%[Objective] The aim was to establish an effective determination method of arsenic in seafood. [Method] Contents of arsenic in seafood samples from eastern Guangdong area were determined by hydride generation-atomic fluorescence spectrometry combined with microwave oven digestion. [Result] The linear range for detection of arsenic was 1.0- 50.0 μg/L, which showed a good linear relationship,and its correlation coefficient was 0.995. The detection limit and relative standard deviation were 0.021 07 μg/L and 0.932% .respectively. Contents of arsenic in some seafood samples were more than the national standard,which could be caused by industrial pollution in coastal areas. [Conclusion] The method is simple,rapid and accurate,so it is applied to the determination of arsenic in seafood samples.

  18. 微波消解-铋膜/Nation修饰电极溶出伏安法测定鳗鱼中的镉含量%Determination of Cadmium in Eel by Microwave Digestion Followed by Stripping Voltammetry on Bismuth/Nation Modified Electrode

    Institute of Scientific and Technical Information of China (English)

    李静; 李红波; 范大和; 王伟

    2011-01-01

    A stripping voltammetric method based on microwave digestion was developed for determining cadmium in eel on a bismuth/nafion modified electrode. Oxidation yield a well-defined square wave peak for Cd^2+ at about - 0.85 V. Nation concentration, bismuth film thickness, buffer solution pH, deposition potential accumulation time and other potential interference factors were investigated. A linear relationship was found between peak area and cadmium concentration over the range of 4.0 to 14.0 μg/L with a correlation coefficient of 0.9964. The limit of detection of the method was 0.2 μg/L. The sensor was highly sensitive and effective to detect cadmium even in the presence of several excess potential interference ions.%运用铋膜/Nation修饰电极耦合微波消解技术测定鳗鱼中的Cd^2+。Cd^2+在-0.85V处出现清晰的方波氧化峰。Nafion、铋膜的厚度、缓冲液的pH值、富集电位、富集时间及可能干扰物质的影响因素进行考察。Cd^2+在4.0~14.0μg/L质量浓度范围内线性关系,线性相关性系数为0.9964,检出限为0.2ug/L。结果表明,该传感器在过量的干扰离子存在条件下,表现出超灵敏性和有效性。

  19. 微波消解-电感耦合等离子体质谱法测定湿基草莓中 15 种微量稀土元素%Determination of 15 Trace Rare Earth Elements in the Fresh Strawberries by Inductively Coupled Plasma-Mass Spectrometry With Microwave Digestion

    Institute of Scientific and Technical Information of China (English)

    杨威

    2016-01-01

    The microwave digestion method was used to decompose the sample, and then 15 trace rare earth elements in the fresh strawberries were determined by inductively coupled plasma-mass spectrometry. The results show that correlation coefficient (r) of the method is between 0.999 5 ~ 1.000 0, recoveries of the method are between 94.2%~106.4%, the precision (RSD%) is less than 6.92%. The method has simple process, high accuracy and precision, the detection limit can meet the requirements, so it is suitable for the determination of trace determination of rare earth elements in the fresh strawberries.%应用微波消解进行样品前处理,电感耦合等离子体质谱法测定湿基草莓中的 15 种微量稀土元素.试验结果表明,该方法相关系数(r)在 0.999 5~1.000 0 之间,方法回收率在 94.2%~106.4%之间,方法精密度(RSD%)低于 6.92%.该方法具有前处理过程简单、引入干扰少、准确度、精密度、检出限满足要求,同时具有线性范围广、测试速度快等特点,适合湿基草莓样品中微量稀土元素的测定.

  20. Application of Microwave Irradiation to Rapid Organic Inclusion Complex

    Institute of Scientific and Technical Information of China (English)

    Yan; Xiaohua

    2001-01-01

    Microwave irradiation has been used in chemical laboratories for moisture analysis and wet asking procedures of biological and geological materials for a number of years [1]. More recently the microwave irradiation also widely used for rapid organic synthesis [2]. However, there have not yet been any reports concerning the ultilisatioin of microwave ovens in the routine organic inclusion complex regularly in chemical research.  ……

  1. 微波消解海泥中BaP的浊点萃取-同步荧光分析%Microwave Digestion Assisted Cloud Point Extraction-Synchronous fluorescence of Benzo (a)pyrene in Ocean Sediments

    Institute of Scientific and Technical Information of China (English)

    翁文婷; 陈桂友; 郑燕玉

    2014-01-01

    建立一种微波消解辅助浊点萃取-同步荧光法测定海洋沉积物中的3,4-苯并(a)芘的新方法.通过加入TritonX-114,采用浊点萃取法对微波消解后的海洋污泥样品中痕量苯并(a)芘进行浓缩萃取,并结合灵敏的同步荧光法测定其含量.探讨影响苯并(a)芘萃取效果的因素,研究发现:最佳波长差为23 nm 时,苯并(a)芘乙醇溶液在384 nm处有一明显的同步荧光峰,BaP的浓度在0.01~0.2 ppm 范围内与荧光峰强度呈良好的线性关系,线性方程为I=1.35+701.77C(ppm),相关系数为0.9998,方法检出限为2.16 ppb.对照传统的甲苯溶剂超声波萃取法的实验结果,该方法具有线性范围宽、检出限低10倍、操作安全无毒的优点.%A new method synchronous fluorescence for the determination of trace 3 ,4-Benzo (a)pyrene (BaP)in Ocean Sediments was proposed by cloud point extracting which assisted with microwave di-gestion.The cloud point extraction method is adopted for marine sludge sample by using 5%(V/V) tritonX-114 solution with assistance of ultrasound,and the trace benzo(a)pyrene was extracted into nonaqueous phase,combined with the sensitivity of synchronous fluorescence method to measure its content in order to explore influence of benzo(a)pyrene extraction effect factors.The study found that fluorescence spectra BaP alcoholic solution has a strong and sharp synchronous fluorescence peak at 384 nm with optimal △λ=23 nm.The relative fluorescence peak intensity and the concentration of BaP show a good linear relationship in range of 0.01~0.2 ppm,linear equation I=1.35+701.77C(ppm) with the correlation coefficient r=0.999 8,the detection of the melamine limits to 2.16 ppb(3 S/K). Contrast to the experimental results of traditional liquid-liquid extraction method with toluene sol-vent,this method has the advantages of high sensitivity,low detection limit and safe non-toxic operat-ing.

  2. Determination of 11 Kinds of Inorganic Elements in Cortex Spondiacis by Microwave Digestion/ICP-MS Method%微波消解-ICP-MS测定傣药嘎哩啰树皮中的11种无机元素

    Institute of Scientific and Technical Information of China (English)

    罗雯; 马金晶; 张龙旺; 陈聪; 叶艳青

    2012-01-01

    The present research aimed to establish a kind of simple and rapid method to detect metal elements in Cortex Spondiacis were determined by microwave digestion and inductively coupled plasma mass spectrometry (ICP-MS). The sample was digested with HNO3-H2O2 acids system. The operation would be simplified and the blank value would be decreased with the above acids systems. Instead of using concent rated acid, this experiment not only can leave out the process of drying or dilution and save time, and extend the life of the instrument, but also eliminates the errors of the inconsistency between digestion solutions and standard solutions. The experimental results showed that Cortex Spondiacis is rich in beneficial elements such as potassium, calcium, magnesium, iron, sodium, and nickel. And the content of harmful elements of the drug, such as mercury, lead, cadmium and arsenic, is under the national rule, which have some medicinal value. Under the optimum working conditions of the instrument, the detection limits were all smaller than 0. 052 1 μg · L‐1, the recovery ratios by standard addition were in the range of 90. 8%~113. 8% and the RSD was smaller than 5. 10% for all elements. Precision and accuracy of determining results are satisfactory. This results are reliable. These results are reliable. The method can meet the need for simultaneity determination of high content element and trace element in Cortex Spondiacis.%建立快速而简便的微波消解-电感耦合等离子体质谱(ICP-MS)法测定傣药嘎哩啰树皮中砷、铅、汞、镉、镍、硒、钙、镁、铁、钾、钠11种无机元素的含量.采用HNO3-H2O2酸溶体系对样品进行消解,以便简化操作,降低空白值.实验避免采用浓酸,可省去赶酸或稀释的步骤,节省时间,延长仪器使用寿命,消除样品溶液与标准溶液酸度之间的误差.实验结果表明,嘎哩啰树皮中富含对人体有利的钾、钙、镁、铁、钠、镍,其有害元素汞、铅

  3. Develpoment of a procedure for the determination of chromium in samples of urine and serum by neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Buettner, I. (Hamburg Univ. (Germany). Inst. for Inorganic and Applied Chemistry); Hamm, V. (Hamburg Univ. (Germany). Inst. for Inorganic and Applied Chemistry); Knoechel, A. (Hamburg Univ. (Germany). Inst. for Inorganic and Applied Chemistry); Sen Gupta, R. (Hamburg Univ. (Germany). Inst. for Inorganic and Applied Chemistry)

    1993-06-01

    Since the mid-fifties the possibility of a causal relationship between deficient chromium and insulin metabolism and the manifestation of certain varieties of diabetes mellitus has been presumed. The determination of the chromium status under pathophysiological conditions may be helpful for the study of this problem. For these purposes an analytical procedure as reference system was developed which allows the determination of chromium in biological matrices down to the concentration of 0.33 ng/ml. It is based on NAA and is used in the framework of a commonly used procedure based on GF-AAS. For its application blood and urine samples are freeze-dried and irradiated. After wet digestion with HNO[sub 3] in a microwave combustion system chromium is separated for measurement from the matrix nuclides with the help of the ion-exchanger Cellex-P. THe individual steps of the procedure were evaluated by means of tracer experiments. (orig.)

  4. Digestive system; Appareil digestif

    Energy Technology Data Exchange (ETDEWEB)

    Moureau-Zabotto, L.; Touboul, E.; Lerouge, D.; Deniaud-Alexandre, E.; Grahek, D.; Foulquier, J.N.; Petegnief, Y.; Gres, B.; El Balaa, H.; Keraudy, K.; Servagi-Vernat, S.S.; Lorchel, F.L.; Crehange, G.C.; Miny, J.M.; Bosset, J.F.B.; Mineur, L.; Chastel, D.; Combescure, C.; Guillot, N.; Garcia, R.; Reboul, F.; Huguet, F.; Andre, T.; Hammel, P.; Artru, P.; Balosso, J.; Ruszniewski, P.; Touboul, E.; Gramont, A. de; Louvet, C.; Moretti, L.; Meert, N.; Magne, N.; Daisne, J.F.; Berben, D.; Bral, S.; Alen, R.; Van Cleef, A.; Florescu, C.; Henry-Amar, M.; Jacob, J.; Ollivier, J.M.; Gallais, M.P.; Guillois, J.M.; Vie, B.; Tournier-Rangeard, L.; Mercier, M.; Gerard, J.P.; Ducreux, M.; Lemanski, C.; Francois, E.; Giovannini, M.; Cvitkovic, F.; Mirabel, X.; Peiffert, D

    2005-11-15

    Seven articles concern the digestive system cancer, mixing of images, toxicity of the chemoradiotherapy, comparison of dosimetry tools, pancreas cancer, rectum cancer, treated by chemoradiotherapy. (N.C.)

  5. Anaerobic Digestion and its Applications

    Science.gov (United States)

    Anaerobic digestion is a natural biological process. The initials "AD" may refer to the process of anaerobic digestion, or the built systems of anaerobic digesters. While there are many kinds of digesters, the biology is basically the same for all. Anaerobic digesters are built...

  6. Anaerobic Digestion and its Applications

    Science.gov (United States)

    Anaerobic digestion is a natural biological process. The initials "AD" may refer to the process of anaerobic digestion, or the built systems of anaerobic digesters. While there are many kinds of digesters, the biology is basically the same for all. Anaerobic digesters are built...

  7. Microwave-Assisted Synthesis of "N"-Phenylsuccinimide

    Science.gov (United States)

    Shell, Thomas A.; Shell, Jennifer R.; Poole, Kathleen A.; Guetzloff, Thomas F.

    2011-01-01

    A microwave-assisted synthesis of "N"-phenylsuccinimide has been developed for the second-semester organic teaching laboratory. Utilizing this procedure, "N"-phenylsuccinimide can be synthesized in moderate yields (40-60%) by heating a mixture of aniline and succinic anhydride in a domestic microwave oven for four minutes. This technique reduces…

  8. RESEARCH ON MICROWAVE HUMIDITY TESTING OF CERAMIC PRODUCTS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This paper analyses the principle of microwave humidity testing. According to the problems in the production procedure of ceramic products, a microwave humidity testing system is designed and analyzed for its advantages. Furthermore, the system has been applied to the production line that produces ceramic products and the testing results are also satisfying.

  9. Microwave accelerated solvent-free synthesis of flavanones

    Energy Technology Data Exchange (ETDEWEB)

    Sagrera, Gabriel J. [Universidad de la Republica, Montevideo (Uruguay). Facultad de Ciencias. Dept. de Quimica Organica]. E-mail: gseoane@fq.edu.uy; Seoane, Gustavo A. [Universidad de la Republica, Montevideo (Uruguay). Facultad de Quimica

    2005-07-15

    Microwave irradiation of chalcones under solvent-free conditions resulted in a 'green-chemistry' procedure for the preparation of flavanones in very good yields. Using an unmodified household microwave oven, different mineral supports and catalysts were tested. By irradiation of chalcones with 30% TFA over silica gel, eleven known flavanones and five new compounds were prepared in high yields. (author)

  10. Microwave combustion and sintering without isostatic pressure

    Energy Technology Data Exchange (ETDEWEB)

    Ebadian, M.A.

    1998-01-01

    In recent years interest has grown rapidly in the application of microwave energy to the processing of ceramics, composites, polymers, and other materials. Advances in the understanding of microwave/materials interactions will facilitate the production of new ceramic materials with superior mechanical properties. One application of particular interest is the use of microwave energy for the mobilization of uranium for subsequent redeposition. Phase III (FY98) will focus on the microwave assisted chemical vapor infiltration tests for mobilization and redeposition of radioactive species in the mixed sludge waste. Uranium hexachloride and uranium (IV) borohydride are volatile compounds for which the chemical vapor infiltration procedure might be developed for the separation of uranium. Microwave heating characterized by an inverse temperature profile within a preformed ceramic matrix will be utilized for CVI using a carrier gas. Matrix deposition is expected to commence from the inside of the sample where the highest temperature is present. The preform matrix materials, which include aluminosilicate based ceramics and silicon carbide based ceramics, are all amenable to extreme volume reduction, densification, and vitrification. Important parameters of microwave sintering such as frequency, power requirement, soaking temperature, and holding time will be investigated to optimize process conditions for the volatilization of uranyl species using a reactive carrier gas in a microwave chamber.

  11. Microwave Breast Imaging Techniques

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy; Rubæk, Tonny

    2010-01-01

    This paper outlines the applicability of microwave radiation for breast cancer detection. Microwave imaging systems are categorized based on their hardware architecture. The advantages and disadvantages of various imaging techniques are discussed. The fundamental tradeoffs are indicated between v...

  12. Microwave Breast Imaging Techniques

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy; Rubæk, Tonny

    2010-01-01

    This paper outlines the applicability of microwave radiation for breast cancer detection. Microwave imaging systems are categorized based on their hardware architecture. The advantages and disadvantages of various imaging techniques are discussed. The fundamental tradeoffs are indicated between...

  13. Advances in microwaves 7

    CERN Document Server

    Young, Leo

    2013-01-01

    Advances in Microwaves, Volume 7 covers the developments in the study of microwaves. The book discusses the effect of surface roughness on the propagation of the TEM mode, as well as the voltage breakdown of microwave antennas. The text also describes the theory and design considerations of single slotted-waveguide linear arrays and the techniques and theories that led to the achievement of wide bandwidths and ultralow noise temperatures for communication applications. The book will prove invaluable to microwave engineers.

  14. Metacomprehension. ERIC Digest.

    Science.gov (United States)

    Standiford, Sally N.

    Intended for administrators and policymakers as well as teachers, this digest explores the nature of students' metacomprehension, or their awareness of their own understanding, and the implications of this awareness for reading instruction. After defining metacomprehension, the digest discusses why this awareness is important to the learning…

  15. Modelling grass digestibility

    NARCIS (Netherlands)

    Groot, J.C.J.

    1999-01-01

    Grass digestibility is determined by the rate of plant development, mass of plant organs (leaf blades, leaf sheaths and stem internodes) and composition of organs. The development of an integrating model for grass digestibility necessitates the quantification of developmental characteristics of plan

  16. Perspectives for anaerobic digestion

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær

    2003-01-01

    to the soil. Anaerobic digestion (AD) is one way of achieving this goal and it will furthermore, reduce energy consumption or may even be net energy producing. This chapter aims at provide a basic understanding of the world in which anaerobic digestion is operating today. The newest process developments...

  17. 微波消解-原子吸收测定柠檬中的 Cu、Zn、Fe 的含量%Microwave Digestion-Detection of Cu,Zn and Fe through Atomic Absorption

    Institute of Scientific and Technical Information of China (English)

    李兴华

    2015-01-01

    This experiment aims to ,using flame atomic absorption spectrometry ,determine through specific ab-sorption procedure the contents of copper , zinc, iron in different parts of lemons when the best atomic absorp-tion spectrometer works.The findings suggest that contents of Cu ,Zn and Fe are respectively 0.709μg/kg,1. 244μg/kg and 14.312μg/kg in lemon juice,0.787μg/kg,2.430μg/kg and 12.971μg/kg in lemon peel,and 3.384μg/kg,5.948μg/kg and 29.773μg/kg in lemon seeds.The experiment provides reference for the safety control of lemon as one of our advantageous fruit resources .%实验对柠檬果实不同部位按照特定的消解程序进行消解,铜、锌、铁三种元素在最佳原子吸收光谱仪工作条件下,采用火焰原子吸收光谱法对其含量进行测定。柠檬果实中,不同部位中铜、锌、铁含量分别为柠檬果汁:0.709μg/kg,1.244μg/kg,14.312μg/kg;柠檬果皮:0.787μg/kg,2.430μg/kg、12.971μg/kg;柠檬籽:3.384μg/kg,5.948μg/kg,29.773μg/kg。实验所建立的柠檬重金属含量测定方法可为四川省优势资源果蔬柠檬的质量安全奠定基础。

  18. Microwave Radiometer (MWR) Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Morris, VR

    2006-08-01

    The Microwave Radiometer (MWR) provides time-series measurements of column-integrated amounts of water vapor and liquid water. The instrument itself is essentially a sensitive microwave receiver. That is, it is tuned to measure the microwave emissions of the vapor and liquid water molecules in the atmosphere at specific frequencies.

  19. Nonlinearities in Microwave Superconductivity

    OpenAIRE

    Ledenyov, Dimitri O.; Ledenyov, Viktor O.

    2012-01-01

    The research is focused on the modeling of nonlinear properties of High Temperature Superconducting (HTS) thin films, using Bardeen, Cooper, Schrieffer and Lumped Element Circuit theories, with purpose to enhance microwave power handling capabilities of microwave filters and optimize design of microwave circuits in micro- and nano- electronics.

  20. [Anaerobic digestion of lignocellulosic biomass with animal digestion mechanisms].

    Science.gov (United States)

    Wu, Hao; Zhang, Pan-Yue; Guo, Jian-Bin; Wu, Yong-Jie

    2013-02-01

    Lignocellulosic material is the most abundant renewable resource in the earth. Herbivores and wood-eating insects are highly effective in the digestion of plant cellulose, while anaerobic digestion process simulating animal alimentary tract still remains inefficient. The digestion mechanisms of herbivores and wood-eating insects and the development of anaerobic digestion processes of lignocellulose were reviewed for better understanding of animal digestion mechanisms and their application in design and operation of the anaerobic digestion reactor. Highly effective digestion of lignocellulosic materials in animal digestive system results from the synergistic effect of various digestive enzymes and a series of physical and biochemical reactions. Microbial fermentation system is strongly supported by powerful pretreatment, such as rumination of ruminants, cellulase catalysis and alkali treatment in digestive tract of wood-eating insects. Oxygen concentration gradient along the digestive tract may stimulate the hydrolytic activity of some microorganisms. In addition, the excellent arrangement of solid retention time, digesta flow and end product discharge enhance the animal digestion of wood cellulose. Although anaerobic digestion processes inoculated with rumen microorganisms based rumen digestion mechanisms were developed to treat lignocellulose, the fermentation was more greatly limited by the environmental conditions in the anaerobic digestion reactors than that in rumen or hindgut. Therefore, the anaerobic digestion processes simulating animal digestion mechanisms can effectively enhance the degradation of wood cellulose and other organic solid wastes.

  1. Topology optimization of microwave waveguide filters

    DEFF Research Database (Denmark)

    Aage, Niels; Johansen, Villads Egede

    2017-01-01

    We present a density based topology optimization approach for the design of metallic microwave insert filters. A two-phase optimization procedure is proposed in which we, starting from a uniform design, first optimize to obtain a set of spectral varying resonators followed by a band gap optimizat......We present a density based topology optimization approach for the design of metallic microwave insert filters. A two-phase optimization procedure is proposed in which we, starting from a uniform design, first optimize to obtain a set of spectral varying resonators followed by a band gap...... little resemblance to standard filter layouts and hence the proposed design method offers a new design tool in microwave engineering....

  2. Color sensing under microwaves

    Science.gov (United States)

    Choudhury, Debesh

    2013-09-01

    Inspired by recent results of artificial color due to Caulfield, we carry out intuitive experimental investigations on color sensing under microwave illumination. Experiemnts have been carried out using a Gunn diode as the microwave source and a microwave diode as a detector. More precise experimental studies have also been carried out utilizing a vector network analyzer. Preliminary results of the experiments validate the feasibility of sensing and discriminating otherwise visual colors under microwave illumination. Caulfield's presumption possibly paves the way for artificial color perception using microwaves.

  3. Microwave-assisted rapid characterization of lipase selectivities.

    Science.gov (United States)

    Bradoo, Sapna; Rathi, Pooja; Saxena, R K; Gupta, Rani

    2002-04-18

    A rapid screening procedure for characterization of lipase selectivities using microwaves was developed. The rate of reaction of various commercial lipases (porcine pancreas, Mucor miehei, Candida rugosa, Pseudomonas cepacia) as well as lipases from laboratory isolates-Bacillus stearothermophilus and Burkholderia cepacia RGP-10 for triolein hydrolysis was 7- to 12-fold higher in a microwave oven as compared to that by pH stat. The esterification of sucrose/methanol and ascorbic acid with different fatty acids was also achieved within 30 s in a microwave using porcine pancreas, B. stearothermophilus SB-1 and B. cepacia RGP-10 lipases. The relative rates and selectivity of the lipases both for hydrolytic and synthesis reactions remains unaltered. However, the rate of reaction was dynamically enhanced when exposed to microwaves. Microwave-assisted enzyme catalysis can become an attractive procedure for rapid characterization of large number of enzyme samples and substrates, which otherwise is a cumbersome and time-consuming exercise.

  4. Determination of Nb and Ta in Nb-Ta Ore by Inductively Coupled Plasma-Optical Emission Spectrometry with a Combined Microwave Digestion Hydrofluoric Acid-resistant System%微波消解-耐氢氟酸系统电感耦合等离子体发射光谱法测定铌钽矿中的铌和钽

    Institute of Scientific and Technical Information of China (English)

    马生凤; 温宏利; 李冰; 王蕾; 朱云

    2016-01-01

    Niobium and tantalum in hydrofluoric acid can form a stable solution,and thus the Nb and Ta content of Nb-Ta ore can be determined accurately by Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) with a hydrofluoric acid resistant system.The determination method described in this paper for Nb and Ta in Nb-Ta ore,uses the microwave digestion mode of modular small tank and multiple digestion tank assembly (70 tank /group),and hydrofluoric acid resistant system of ICP-OES.This method shortens the dissolution time from 48 h to 1 h.By using a hydrofluoric acid medium the hydrolysis of high-level Nb and Ta in low acid concentration media is avoided.The detection limits of this method are 5.58 μg/g for Nb and 5.87 μg/g for Ta.The result of Nb-Ta concentrate with 19% Nb2 O5 and 27% Ta2 O5 is consistent with that acquired by the alkali fusion method and can be used to determine both high-grade and low-grade Nb-Ta ore with 42 μg/g -19% of Nb2 O5 and 86 μg/g -27%of Ta2 O5 .The main advantage of this method is to accurately determine Nb and Ta in high-grade Nb-Ta ore.%铌、钽在氢氟酸介质中能够形成稳定的溶液,使用耐氢氟酸进样系统的电感耦合等离子体发射光谱(ICP -OES)有利于提高分析的准确性。本文采用模块化的小罐型、多罐体组合(70罐/组)酸溶罐体的微波消解溶样模式,结合 ICP -OES 仪器的耐氢氟酸进样系统,建立了测定铌钽矿中铌、钽的分析方法。本方法加快了酸溶的溶样速度,溶样时间从原来的48 h 减少至1 h,且在氢氟酸介质中测定避免了高含量铌、钽在低酸度介质中容易水解的影响。方法检出限为铌5.58μg/g,钽5.87μg/g。本方法应用于测定铌钽精矿(19%Nb2 O5,27%Ta2 O5)的分析结果与碱熔方法一致,能够测定 Nb2 O5含量在42μg/g ~19%和 Ta2 O5含量在86μg/g ~27%高低品位的铌钽矿,尤其对于铌、钽在百分含量以上的铌钽矿具有优势。

  5. Determination of Eight Metal Elements in Cichorium glandulosum Boiss et Huet by Microwave Digestion-FAAS%用微波消解法-FAAS测定民族药腺毛菊苣根中八种金属元素的含量

    Institute of Scientific and Technical Information of China (English)

    裴凌鹏; 周晓英; 崔箭; 庞宗然; 刘宏炳; 葛亮

    2009-01-01

    The Cichorium glandulosum Boiss et Huet is a traditional Uighur natural herbal medicine, but has not been analyzed and studied in terms of its metal elements. In the experiment, the Cichorium glandulosum Boiss et Huet powder was digested with HNO_3 by microwave digestion before determination. The eight metal elements, potassium, nickel, calcium, magnesium, iron, manganese, copper and zinc, in Cichorium glandulosum Boiss et Huet were determined by FAAS. The working conditions, accuracy and precision of the method were studied. The linear correlations of standard curves are good (r=0. 999 1-0. 999 9). The recovery (n=6) is 92. 25%-110. 5%, and the RSD (n=6) is 0. 7%-3.88%. The results showed that there were compara-tively rich metal elements, among which are comparatively high calcium (65.84 mg·g~(-1) ), iron (24.38 mg·g~(-1) ), magnesium (278. 17 mg·g~(-1)) and potassium (18. 50 mg·g~(-1)), in Cichorium glandulosum Boiss et Huet, and the contents of other ele-ments are nickel of 0. 004 38 mg·g~(-1), manganese of 0. 52 mg·g~(-1), copper of 0. 016 5 mg·g~(-1) and zinc of 0. 18 mg·g~(-1).This provided useful data for discussing the relationship between the content of the metal elements in Cichorium glandulosumBoiss et Huet and its clinical application in cardiovascular and osteoporosis disease.%腺毛菊苣是新疆维吾尔族传统习用药材,但其药物中有效微量、常量元素成分尚未进行过分析研究.试验采用HNO_3作为消解液,利用微波消解的方法处理样品,原子吸收分光光度法测定维吾尔药材菊苣根中钾(K)、镍(Ni)、钙(Ca)、镁(Mg)、铁(Fe)、锰(Mn)、铜(Cu)和锌(Zn)八种微量、常量元素的含量,精密度和回收率较好,回收率控制在92.25%~110.5%之间,相对标准偏差RSD≤3.88%.结果显示新疆菊苣中Mg,Ca,Fe,K等人体所需的必须微量元素含量十分丰富,特别是Mg和Ca含量较高,分别达到278.17和65.84 mg·g~1.其他元素中Mg和Zn含量

  6. 微波消解-原子荧光法测定染毒小鼠体内汞的分布∗%Study on Hg distribution in different tissues of rats by hydride generation atomic fluorescence spectroscopy with microwave digestion

    Institute of Scientific and Technical Information of China (English)

    王梅; 龙军标; 杨冰仪; 徐英; 陈浩峰; 邹志辉

    2013-01-01

    The concentrations of mercury in brain, testis, spleen, liver, kidney and blood were measured by AFS with microwave digestion after rats were injected intraperitoneally with different doses of mercury chloride. The results showed mercury concentrations in brain, testis, spleen, liver and kidney were significantly correlated to administrated dose and statistically higher than those in the control group (P < 0. 05). And the accumulated quantity of mercury in target organs decreased in order of kidney, liver, spleen, testis, and brain. Total mercury concentrations of whole blood and total mercury in various organs were statistically significantly correlated (P < 0. 01). The detection limit was 0. 002 μg·L - 1 , and the recovery tested by adding standards ranged from 92. 1% to 108. 5% . The method was simple and high sensitivity, which provided a basis for study of concentrations of mercury in different tissues of biologies.%  小鼠经腹腔注射氯化汞(HgCl2)染毒后,采用微波消解-原子荧光法研究汞在小鼠全血、脑、睾丸、脾、肝脏以及肾脏的分布情况.结果表明,方法的检出限为0.002μg·L -1,加标回收率为92.12%—108.46%.该方法操作简便,灵敏度高,检出限低,线性范围宽,可作为生物体内汞含量的测定方法.汞在染毒小鼠血和各脏器中含量随染汞剂量的增加而明显增加,与对照组相比差异有统计学意义(P <0.05);小鼠体内总汞绝大部分蓄积在肾脏内,其次是肝脏,然后是脾、睾丸、脑;全血的总汞含量与肾脏、肝脏、脾、睾丸、脑的总汞含量有相关性.

  7. 微波消解-ICP-MS法同时测定鱼油类保健食品中6种微量元素%Determination of six kinds of trace elements in fish oil health food by microwave digestion-ICP-MS method

    Institute of Scientific and Technical Information of China (English)

    李俊婕; 李启艳; 于海英; 林钰镓; 王小兵

    2016-01-01

    Objective To establish an ICP-MS method for the determination of aluminum,cadmium,total chromium, copper,zinc and nickel in fish oil health food.Methods Samples were determinated by microwave digestion and inductively coupled plasma atomic emission spectrometry.Results The calibration curve of 6 elements were linear in the concentration range of 0~100 mg·L-1.Standard addition recovery rates were 98.8%~103.4% on average,the RSDs of precisions were in 1.6%~2.8%,the RSDs of repeatabilities were in 0.66%~4.91%.Conclusion This method was simple,rapid and accurate for the determination of fish oil health food in 6 elements,and can provide technical support for the national health food su-pervision,testing and risk monitoring.%目的:建立微波消解电感耦合等离子体质谱法同时测定鱼油类保健食品中铝、镉、总铬、铜、锌、镍的含量。方法采用微波消解法处理样品,电感耦合等离子体质谱法测定。结果6种元素中在0~100 mg·L-1范围内,线性关系良好。平均加样回收率在98.8%~105.2%之间,精密度RSD在1.6%~2.8%,重复性RSD在0.66%~4.91%。结论本方法简便快速准确,可用于鱼油中6种微量元素的测定,为国家保健食品监督抽验和风险监测工作提供技术支持。

  8. Determination of phosplorus, nickel, copper, titanium and vanadium in ferromanganese by microwave digestion-inductively coupled plasma atomic emission soectrometry%微波消解—电感耦合等离子体发射光谱法测定锰铁中磷镍铜钛钒

    Institute of Scientific and Technical Information of China (English)

    赵容超; 李海平; 杨大蔚; 井婷婷

    2012-01-01

    锰铁样品经微波消解后,选择327.395、231.604、177.434、334.941、309.310 nm波长的光谱线分别作为铜、镍、磷、钛、钒的分析线,用电感耦合等离子体发射光谱法测定了锰铁样品中铜、镍、磷、钛、钒含量.基体锰产生的基体效应可以通过基体匹配的方法消除,基体铁对测定没有影响.方法用于测定锰铁标样,测定值与认定值一致;用于测定锰铁试样,测定结果的相对标准偏差在0.2%0~3.6%o之间,加标回收率为97%~103%.方法可以用于中、高、低碳锰铁中铜、镍、磷、钛、钒的测定.%After pretreatment with microwave digestion and selection of spectral lines at the wavelength of 327. 395,231. 604,177. 434,334. 941 and 309. 310 nm as the analytical line of copper, nickel, phosphorus, titanium and vanadium, respectively, the content of copper, nickel, phosphorus, titanium and vanadium in ferromanganese sample was determined by inductively coupled plasma atomic e-mission spectrometry. The matrix effect produced by matrix manganese could be eliminated by matrix matching while the matrix iron did not have influence on the determination. When the method was applied to determine ferromanganese certified reference materials, the determination results were the same as the certified values. When it was applied to determine ferromanganese actual samples, relative standard deviations of the determination results were between 0. 2% and 3. 6% and recoveries were between 97% and 103%. The method could be used to determine copper, nickel, phosphorus, titanium and vanadium in the medium, high and low-carbon ferromanganese.

  9. Determination of lead, arsenic, cadmium, chromium, nickel in sea products by inductively coupled plasma mass spectrometry with microwave digestion%微波消解-电感耦合等离子体质谱测定水产品中铅、砷、镉、铬、镍含量

    Institute of Scientific and Technical Information of China (English)

    解楠; 曹程明; 徐红斌; 葛宇

    2011-01-01

    Inductively coupled plasma mass spectrometry (ICP-MS) with microwave digestion was applied to determine lead,arsenic,cadmium,chromium and nickel in sea products.The linear ranged of the method was from 0 to 200ng/mL,and linear correlation factors for each element were good(r>0.9995).The detection limits were between 0.012 to 0.091 ng/mL Precision was fine,and RSD was lower than 5%,and recoveries of sea products samples were in the range of 86.1%~115.5%.The results showed close agreement with the reference values in three standard reference materials of GBW08571 ,GBW08521 ,GBW07605( GSV-4).lt indicated that the method was simple,sensitive,accurate and short of analytical cycle,which could meet the demand for the determining heavy metal elements in sea products.%研究了同时准确测定的水产品中铅、砷、镉、铬、镍元素方法.采用微波消解仪对样品进行前处理、电感耦合等离子体质谱测定5种元素含量.实验表明,所有元素标准曲线的线性范围均在0~200ng/mL之间,线性方程相关系数(r)均大于0.9995,检出限为0.012~0.091ng/mL,RSD<5%,加标回收率在86.1%~115.5%之间,并以标准物质GBW08571、GBW08521、GBW07605(GSV-4)对方法进行了评价,各元素测定值均在标准值范围之内.该方法具有简单、快速、灵敏、准确的优点,能够对水产品中的重金属元素进行测定.

  10. High brightness microwave lamp

    Science.gov (United States)

    Kirkpatrick, Douglas A.; Dolan, James T.; MacLennan, Donald A.; Turner, Brian P.; Simpson, James E.

    2003-09-09

    An electrodeless microwave discharge lamp includes a source of microwave energy, a microwave cavity, a structure configured to transmit the microwave energy from the source to the microwave cavity, a bulb disposed within the microwave cavity, the bulb including a discharge forming fill which emits light when excited by the microwave energy, and a reflector disposed within the microwave cavity, wherein the reflector defines a reflective cavity which encompasses the bulb within its volume and has an inside surface area which is sufficiently less than an inside surface area of the microwave cavity. A portion of the reflector may define a light emitting aperture which extends from a position closely spaced to the bulb to a light transmissive end of the microwave cavity. Preferably, at least a portion of the reflector is spaced from a wall of the microwave cavity. The lamp may be substantially sealed from environmental contamination. The cavity may include a dielectric material is a sufficient amount to require a reduction in the size of the cavity to support the desired resonant mode.

  11. Avaliação da digestibilidade de nutrientes, em bovinos, de alguns alimentos concentrados pela técnica de três estádios Evaluation of intestinal digestibility of different concentrate feeds using an in vitro three-step enzymatic procedure

    Directory of Open Access Journals (Sweden)

    Fernando Henrique Brussi Beran

    2007-02-01

    Full Text Available Este trabalho foi realizado com o objetivo de determinar a digestibilidade de componentes nutricionais não-degradados no rúmen por meio da técnica de três estádios. Foram avaliados oito alimentos concentrados: grão de girassol integral (GI, torta de girassol com uma (TG1x e com duas passagens pela prensa (TG2x, grão de soja integral (SI e parcialmente desengordurado (SD, farelo de soja (FS, farelo de gérmen de milho desengordurado (GM e concentrado comercial (CC com 36% de PB. Os alimentos foram incubados no rúmen de bovinos por 33, 20 e 12 horas, correspondendo a taxas de passagens de 3, 5 e 8%/h, respectivamente. Os resíduos não-degradados no rúmen foram submetidos à digestão com solução de pepsina com pH 1,9 durante 1 hora e, posteriormente, em solução de pancreatina com pH 7,8 durante 24 horas, ambas a 38ºC. Nos resíduos desta incubação, foram determinados a MS, MO e os teores de nitrogênio total. A digestibilidade intestinal in vitro da MS não degradada no rúmen, considerando taxa de passagem de 5%/h, variou de 7,88 a 37,72%, sendo que o CC e a SI apresentaram as maiores digestibilidades. A digestibilidade da PB não-degradada no rúmen variou de 13,67 a 81,76% para mesma taxa de passagem. O GI apresentou a menor e o CC e o FS as maiores digestibilidades da PB. A digestibilidade da MO variou de 7,93 a 37,14% para a mesma taxa de passagem, sendo que o GI foi o menos digestível e o CC e a SI, os mais digestíveis. Os menores valores para a proteína digestível não degradável no rúmen (PNDR D, em g/kgMS, foram obtidos nas tortas de girassol com uma ou duas passagens, sugerindo que estes alimentos não devem ser empregados quando se deseja maiores teores de PNDR D.The objective of this trial was to determine the intestinal digestibility of nutrients using an in vitro three-step enzymatic procedure. Eight concentrate feeds were evaluated: whole sunflower (WSF, mechanically pressed sunflower cake (SFC1x; one press

  12. Analytical Chemistry Laboratory (ACL) procedure compendium. Volume 2, Sample preparation methods

    Energy Technology Data Exchange (ETDEWEB)

    1993-08-01

    This volume contains the interim change notice for sample preparation methods. Covered are: acid digestion for metals analysis, fusion of Hanford tank waste solids, water leach of sludges/soils/other solids, extraction procedure toxicity (simulate leach in landfill), sample preparation for gamma spectroscopy, acid digestion for radiochemical analysis, leach preparation of solids for free cyanide analysis, aqueous leach of solids for anion analysis, microwave digestion of glasses and slurries for ICP/MS, toxicity characteristic leaching extraction for inorganics, leach/dissolution of activated metal for radiochemical analysis, extraction of single-shell tank (SST) samples for semi-VOC analysis, preparation and cleanup of hydrocarbon- containing samples for VOC and semi-VOC analysis, receiving of waste tank samples in onsite transfer cask, receipt and inspection of SST samples, receipt and extrusion of core samples at 325A shielded facility, cleaning and shipping of waste tank samplers, homogenization of solutions/slurries/sludges, and test sample preparation for bioassay quality control program.

  13. Steam Digest 2001

    Energy Technology Data Exchange (ETDEWEB)

    2002-01-01

    Steam Digest 2001 chronicles BestPractices Program's contributions to the industrial trade press for 2001, and presents articles that cover technical, financial and managerial aspects of steam optimization.

  14. Protein digestion in ruminants

    African Journals Online (AJOL)

    protein nitrogen (NPN) in the rumen, the effect of digestible energy on the rate and .... Fahey, 1982) and inhibitors of amino acid deamination. (Chalupa & Scott, 1976). ... the omasum, although both urea and ammonia may be absorbed (0,9 gld.

  15. Restriction endonucleases digesting DNA in PCR buffer

    Institute of Scientific and Technical Information of China (English)

    LIU Xue-dong; ZHENG Dong; ZHOU Yan-na; MAO Wei-wei; MA Jian-zhang

    2005-01-01

    Six commonly used restriction endonucleases (Res) (Acc I, Ban II, EcoR I, Hind III, Sac I, Sca I) were tested for their ability to directly digest DNA completely in the Polymerase Chain Reaction (PCR) buffers. The results showed that: with the requirement for additional magnesium supplemented as activator, Res, except EcoR I appeared star activity, completely digested unmethylated lambda DNA after overnight incubation in PCR buffer and functioned as equally well as in recommended Restriction Enzyme Buffer provided with each enzyme; all Res tested completely digested PCR products in PCR buffer, it implied digestion of PCR products may often be performed directly in the PCR tube without the requirement for any precipitation or purification steps; and the concentration of MgCl2 from 2.5 mmol·L-1 to 10 mmol·L-1 did not significantly affect activity of Res in PCR buffer. This simplified method for RE digestion of PCR products could have applications in restriction fragment length polymorphism (RFLP) analysis and single-stranded conformational polymorphism (SSCP) analysis of large PCR products. However, usage of this procedure for cloning applications needs further data.

  16. 微波消解-电感耦合等离子体质谱法测定人乳中24种矿物质含量%Determination of 24 minerals in human milk by inductively coupled plasma mass spectrometry with microwave digestion

    Institute of Scientific and Technical Information of China (English)

    孙忠清; 岳兵; 杨振宇; 李筱薇; 吴永宁; 荫士安

    2013-01-01

    Objective To determine the levels of 24 minerals in human milk by inductively coupled plasma mass spectrometry with microwave digestion.Methods The samples were digested by microwave.The contents of minerals were determined by inductively coupled plasma mass spectrometry.The standard reference minerals of 1849a and 1568a from National Institute of Science and Technology were used for quality control.The accuracy and reproduability for this method were evaluated with mix standards and 1849a and 1568a standard reference materals.Results The ranges of the levels of sodium,magnesium,phosphorus,potassium,calcium,aluminum,chromium,arsenic,selenium,iron,zinc,manganese,copper,molybdenum,vanadium,cobalt,nickel,gallium,cadmium,silver,strontium,cesium,barium,lead in human milk was 34.97-415.83mg/kg,19.00-39.52mg/kg,102.13-274.53mg/kg,351.19-713.99mg/kg,180.08-349.64mg/kg,0.06-0.44mg/kg,0.9-7.37μg/kg,0.92-2.72μg/kg,0.20-21.15μg/kg,0.10-0.70mg/kg,0.56-3.25mg/kg,3.00-16.12μg/kg,62.16-591.69μg/kg,0.02-6.91 μg/kg,5.99-13.70μg/kg,0.07-2.11μg/kg,0.77-209.26μg/kg,0.005-0.28 μg/kg,0.02-0.23 μg/kg,0.02-0.71 μg/kg,36.89-132.26 μg/kg,0.01-4.72 μg/kg,0.83-28.16μg/kg,2.5-5.3μg/kg,respectively.The levels of minerals in human milk in present study were consisted with other similar studies.Conclusion The experiment examined the levels of minerals in human milk satisfactorily.The method has high accuracy and good reproducibility,which could be used for understanding the levels of minerals in human milk.%目的 用微波消解-电感耦合等离子体质谱法测定人乳中24种矿物质,以评价人乳的矿物质水平.方法 样品经微波消解后,用电感耦合等离子质谱仪测定24种元素.以加标实验和美国NIST的标准参考物质1849a、1568a考察方法的准确性与重现性.结果 本实验检测的人乳中钠、镁、磷、钾、钙、铝、铬、砷、硒、铁、锌、锰、铜、钼、钒、钴、镍、镓、镉、银、锶、铯、

  17. Research on determination of selenium in foods by inductively coupled plasma mass spectrometry based on collided reaction cell technology with microwave digestion%微波消解-碰撞反应池技术电感耦合等离子体质谱法测定粮食中硒的方法研究

    Institute of Scientific and Technical Information of China (English)

    殷忠

    2012-01-01

    目的 建立测定粮食硒的微波消解-碰撞反应池技术电感耦合等离子体质谱法,为准确定量粮食含硒量提供新的可靠方法.方法 样品经微波消化后直接采用碰撞反应池电感技术结合耦合等离子体质谱仪(ICP-MS)进行测定.用锆(90Zr)内标校正基体干扰和漂移,用高性能Xs接口降低非质谱干扰,用碰撞反应池技术(CRCT模式)消除质谱干扰.结果 方法的标准曲线最佳线性范围为0 ~ 100 μg/L,相关系数为0.999 8.方法检出限0.002 5 mg/kg,最低检出浓度为0.007 5 mg/kg,相对标准偏差1.6% ~4.5%,回收率为94.0% ~ 104.0%.对3个标准参考物质小麦粉(GBW08503)、大米(GBW10010)、小麦(GBW10011)的测定值(0.059、0.073、0.048 mg/kg)均在标准值(0.049±0.014) mg/kg、(0.061±0.015) mg/kg、(0.053±0.007) mg/kg范围内,分析结果令人满意.结论 本法不仅检出限低、操作简便、快速,同时又有良好的重复性、较高的回收率,对样品的测定结果与仲裁法(氢化物原子荧光法)一致,能用于粮食硒的准确测定.%Objective To establish a new and reliable method for the accurate determination of selenium (Se) contents in foods by inductively coupled plasma mass spectrometry based on collided reaction cell technology with microwave digestion. Methods After microwave digestion, samples were directly determined by inductively coupled plasma mass spectrometry based on collided reaction cell technology. Internal standard element of zirconium ( Zr) was used to correct matrix interferences and signal drifting, high-performance Xs ( X sensitive) interface was used to reduce non-mass spectrum interferences, and the collided reaction cell technology ( CRCT mode) was used to eliminate mass spectrum interferences. Results The optimal linear range of the standard curve was 0 - 100 u,g/L with a correlation coefficient of 0.999 8. The detection limit, the lowest quantitative limit, the relative standard deviation and

  18. Digestive ripening of nanoparticles

    Science.gov (United States)

    Irzhak, V. I.

    2017-08-01

    A relatively new method of regulating the size distribution function of nanoparticles—digestive ripening— was described. A hypothetical mechanism of dissolution of nanoparticles was proposed. It includes the effect of the ligand layer on the internal stability of the nanoparticle nucleus: the change in the structure of the ligand layer caused by a decrease in the nanoparticle size determines the kinetics of digestive ripening.

  19. Immobilization of trypsin onto multifunctional meso-/macroporous core-shell microspheres: A new platform for rapid enzymatic digestion

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Gong [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Changchun 130022 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Chen, Ping [Key Laboratory of Marine Bioresources and Ecology, College of Life Science, Shenzhen University, Shenzhen 518060 (China); Wang, Zhi-Gang; Sui, Xiao-Jing [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Changchun 130022 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Ji-Lin, E-mail: zjl@ciac.ac.cn [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Changchun 130022 (China); Ni, Jia-Zuan [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Changchun 130022 (China); Key Laboratory of Marine Bioresources and Ecology, College of Life Science, Shenzhen University, Shenzhen 518060 (China)

    2014-02-17

    Graphical abstract: -- Highlights: •A novel microwave-assisted tryptic digestion system. •Characterization with SEM, TEM, EDX, XRD, and FT-IR. •The meso-/macroporous shell structure withthe high affinity and loading capacity of trypsin. •Decrease of digestion time up to less than 1 min. •MALDI-MS and nanoLC-MS analysis with database identification. -- Abstract: A simple, fast, efficient, and reusable microwave-assisted tryptic digestion system which was constructed by immobilization of trypsin onto porous core-shell Fe{sub 3}O{sub 4}@fTiO{sub 2} microspheres has been developed. The nanostructure with magnetic core and titania shell has multiple pore sizes (2.4 and 15.0 nm), high pore volume (0.25 cm{sup 3} g{sup −1}), and large surface area (50.45 m{sup 2} g{sup −1}). For the proteins, the system can realize fast and efficient microwave-assisted tryptic digestion. Various standard proteins (e.g., cytochrome c (cyt-c), myoglobin (MYO), β-lactoglobulin (β-LG), and bovine serum albumin (BSA)) used can be digested in 45 s under microwave radiation, and they can be confidently identified by mass spectrometry (MS) analysis; even the concentration of substrate is as low as 5 ng μL{sup −1}. Furthermore, the system for the 45 s microwave-assisted tryptic digestion is still effective after the trypsin-immobilized microspheres have been reused for 5 times. Importantly, 1715 unique proteins from 10 μg mouse brain proteins can be identified with high confidence after treatment of 45 s microwave-assisted tryptic digestion.

  20. Using your microwave oven. Lesson 6, Microwave oven management

    OpenAIRE

    Woodard, Janice Emelie, 1929-

    1984-01-01

    Discusses cooking and reheating foods in microwave ovens, and adapting conventional recipes for the microwave. Revised Includes the publication: Adapting conventional recipes to microwave cooking : fact sheet 84 by Janice Woodard, Rebecca Lovingood, R.H. Trice.

  1. Using your microwave oven. Lesson 6, Microwave oven management

    OpenAIRE

    Woodard, Janice Emelie, 1929-

    1984-01-01

    Discusses cooking and reheating foods in microwave ovens, and adapting conventional recipes for the microwave. Revised Includes the publication: Adapting conventional recipes to microwave cooking : fact sheet 84 by Janice Woodard, Rebecca Lovingood, R.H. Trice.

  2. Anti-nutritional Factors and Ruminal Dry Matter and Crude Protein Degradability of Gamma and Microwave Irradiated Native Rapeseed

    Directory of Open Access Journals (Sweden)

    sayyed roohollah ebrahimimahmoudabad

    2016-08-01

    Full Text Available Introduction Native rapeseed (NRS is planted in some parts of Iran because of climatic condition. The consumption of NRS in animal nutrition is limited by anti-nutritional such as phytic acid and glucosinolate. Moreover, the protein of NRS is highly degraded by rumen microorganisms. Several processing methods have been used to enhance the nutritive value of whole oilseeds, including extrusion, roasting, toasting and Jet-Sploding. However, most heat processing methods adversely affect protein digestibility in the small intestine. Recently, other processing methods such as processing by gamma and microwave irradiation have been noticed. Therefore, this research was carried out to evaluate the effects of gamma irradiation (15, 30 and 45 kGy and microwave irradiation (800 W for 2, 4 and 6 min on ruminal dry matter (DM and crude protein (CP degradability, in vitro CP digestibility, anti-nutritional factors (glucosinolate and phytic acid and chemical composition of NRS. Materials and Methods Chemical composition (DM, CP, EE and Ash of untreated and irradiated NRS was determined by AOAC methods. Then, sufficient water was added to the sample to increase the moisture content to 250 g/kg. Gamma irradiation was completed by using a cobalt-60 irradiator at 20 ºC. The dose rate determined by Fricke dosimetry was 0.36 Gy/s. Another three samples (500 g each were subjected to microwave irradiation at a power of 800 W for 2, 4 and 6 min. Phytic acid and glucosinolate contents of untreated and irradiated samples were determined by standard methods. Degradation kinetics of DM or CP were determined according to in situ procedure. Six grams of untreated or irradiated NRS were incubated in the rumen of three ruminally fistulated Taleshi bulls for 0, 2, 4, 8, 16, 24 and 48 h. Bags were placed in the rumen just before the bulls were offered their first meal. After retrieval from the rumen, bags were thoroughly washed with tap water until the rinsing water was clear

  3. Topology optimization of microwave waveguide filters

    CERN Document Server

    Aage, Niels

    2016-01-01

    We present a density based topology optimization approach for the design of metallic microwave insert filters. A two-phase optimization procedure is proposed in which we, starting from a uniform design, first optimize to obtain a set of spectral varying resonators followed by a band gap optimization for the desired filter characteristics. This is illustrated through numerical experiments and comparison to a standard band pass filter design. It is seen that the carefully optimized topologies can sharpen the filter characteristics and improve performance. Furthermore, the obtained designs share little resemblance to standard filter layouts and hence the proposed design method offers a new design tool in microwave engineering.

  4. Microwave and RF engineering

    CERN Document Server

    Sorrentino, Roberto

    2010-01-01

    An essential text for both students and professionals, combining detailed theory with clear practical guidance This outstanding book explores a large spectrum of topics within microwave and radio frequency (RF) engineering, encompassing electromagnetic theory, microwave circuits and components. It provides thorough descriptions of the most common microwave test instruments and advises on semiconductor device modelling. With examples taken from the authors' own experience, this book also covers:network and signal theory;electronic technology with guided electromagnetic pr

  5. Advanced microwave processing concepts

    Energy Technology Data Exchange (ETDEWEB)

    Lauf, R.J.; McMillan, A.D.; Paulauskas, F.L. [Oak Ridge National Lab., TN (United States)

    1997-04-01

    The purpose of this work is to explore the feasibility of several advanced microwave processing concepts to develop new energy-efficient materials and processes. The project includes two tasks: (1) commercialization of the variable-frequency microwave furnace; and (2) microwave curing of polymeric materials. The variable frequency microwave furnace, whose initial conception and design was funded by the AIM Materials Program, allows the authors, for the first time, to conduct microwave processing studies over a wide frequency range. This novel design uses a high-power traveling wave tube (TWT) originally developed for electronic warfare. By using this microwave source, one can not only select individual microwave frequencies for particular experiments, but also achieve uniform power densities over a large area by the superposition of many different frequencies. Microwave curing of various thermoset resins will be studied because it holds the potential of in-situ curing of continuous-fiber composites for strong, lightweight components or in-situ curing of adhesives, including metal-to-metal. Microwave heating can shorten curing times, provided issues of scaleup, uniformity, and thermal management can be adequately addressed.

  6. Advanced microwave processing concepts

    Energy Technology Data Exchange (ETDEWEB)

    Lauf, R.J.; McMillan, A.D.; Paulauskas, F.L. [Oak Ridge National Laboratory, TN (United States)

    1995-05-01

    The purpose of this work is to explore the feasibility of several advanced microwave processing concepts to develop new energy-efficient materials and processes. The project includes two tasks: (1) commercialization of the variable-frequency microwave furnace; and (2) microwave curing of polymer composites. The variable frequency microwave furnace, whose initial conception and design was funded by the AIC Materials Program, will allow us, for the first time, to conduct microwave processing studies over a wide frequency range. This novel design uses a high-power traveling wave tube (TWT) originally developed for electronic warfare. By using this microwave source, one can not only select individual microwave frequencies for particular experiments, but also achieve uniform power densities over a large area by the superposition of many different frequencies. Microwave curing of thermoset resins will be studied because it hold the potential of in-situ curing of continuous-fiber composites for strong, lightweight components. Microwave heating can shorten curing times, provided issues of scaleup, uniformity, and thermal management can be adequately addressed.

  7. Advances in microwaves 3

    CERN Document Server

    Young, Leo

    2013-01-01

    Advances in Microwaves, Volume 3 covers the advances and applications of microwave signal transmission and Gunn devices. This volume contains six chapters and begins with descriptions of ground-station antennas for space communications. The succeeding chapters deal with beam waveguides, which offer interesting possibilities for transmitting microwave energy, as well as with parallel or tubular beams from antenna apertures. A chapter discusses the electron transfer mechanism and the velocity-field characteristics, with a particular emphasis on the microwave properties of Gunn oscillators. The l

  8. Laboratory intercomparison of marine particulate digestions including Piranha: a novel chemical method for dissolution of polyethersulfone filters

    National Research Council Canada - National Science Library

    Ohnemus, Daniel C; Auro, Maureen E; Sherrell, Robert M; Lagerström, Maria; Morton, Peter L; Twining, Benjamin S; Rauschenberg, Sara; Lam, Phoebe J

    2014-01-01

    .... In preparation for these analyses, we conducted a four laboratory intercomparison exercise to determine our degree of intercalibration and to examine how several total digestion procedures perform...

  9. Artificial color perception using microwaves

    CERN Document Server

    Choudhury, Debesh

    2013-01-01

    We report the feasibility of artificial color perception under microwave illumination using a standard microwave source and an antenna. We have sensed transmitted microwave power through color objects and have distinguished the colors by analyzing the sensed transmitted power. Experiments are carried out using a Gunn diode as the microwave source, some colored liquids as the objects and a microwave diode as the detector. Results are presented which open up an unusual but new way of perceiving colors using microwaves.

  10. Polymorph-dependent titanium dioxide nanoparticle dissolution in acidic and alkali digestions

    Science.gov (United States)

    Multiple polymorphs (anatase, brookite and rutile) of titanium dioxide nanoparticles (TiO2-NPs) with variable structures were quantified in environmental matrices via microwave-based hydrofluoric (HF) and nitric (HNO3) mixed acid digestion and muffle furnace (MF)-based potassium ...

  11. NOVEL MICROWAVE FILTER DESIGN TECHNIQUES.

    Science.gov (United States)

    ELECTROMAGNETIC WAVE FILTERS, MICROWAVE FREQUENCY, PHASE SHIFT CIRCUITS, BANDPASS FILTERS, TUNED CIRCUITS, NETWORKS, IMPEDANCE MATCHING , LOW PASS FILTERS, MULTIPLEXING, MICROWAVE EQUIPMENT, WAVEGUIDE FILTERS, WAVEGUIDE COUPLERS.

  12. The Vocational-Technical Resource Consortia Serving Business and Industry in Ohio. Digest of Study: Operational Procedures for Successful Vocational-Technical Resource Consortia in Serving Business and Industry in Ohio.

    Science.gov (United States)

    Frasier, James E.; Stanton, William

    This publication reports the development of the vocational-technical resource consortia in Ohio and identifies the operational procedures associated with successful programs. Five exemplary consortia were studied in some depth; however, data were obtained from all of the 23 consortia in the state. The research indicates that the consortium is an…

  13. Evaluation of lubricating oil preparation procedures for the determination of Al, Ba, Mo, Si and V by high-resolution continuum source FAAS.

    Science.gov (United States)

    Amorim Filho, Volnei Resta; Gomes Neto, José Anchieta

    2009-01-01

    Microwave-assisted acid decomposition and oil-in-water emulsification were evaluated as sample pretreatment procedures to determine Al, Ba, Mo, Si and V in lubricating oils by high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS). Average recoveries of Al, Ba and V in oil digests (107, 103 and 101%) were close to those obtained for emulsions prepared in kerosene medium (94, 113 and 95%). Average recoveries for Mo were close to 105 and 46% for emulsions and digests, respectively. Improved average recoveries (101%) were obtained for Mo in digests using the analyte addition technique. Silicon was successfully quantified only in digested samples. Limits of quantification for Al, Ba, Mo and V were 1.4, 31.5, 1.5 and 11.4-fold lower than those obtained by line-source FAAS. Enhanced sensitivity, multi-elemental capability, and high sample throughput are among the main advantages of HR-CS FAAS in comparison with the line-source FAAS technique.

  14. 矿物药朱砂加工流程中可溶性重金属含量的仿生提取-ICP-OES测定方法%Determination method of soluble heavy metals in mineral medicine cinnabaris in process of production and processing by ICP-OES with bionic extraction and microwave digestion technology

    Institute of Scientific and Technical Information of China (English)

    蒋秋桃; 曾丽; 马杰; 李文莉; 丁野; 李洁

    2016-01-01

    收集朱砂生产加工工艺流程中不同工艺点的样品,采用仿生提取−电感耦合等离子体发射原子光谱法(仿生提取-ICP-OES法)对朱砂样品中可溶性重金属含量进行测定。研究结果表明:仿生提取-ICP-OES法能满足13种重金属同时检测要求,13种重金属线性范围均在0.1~1000.0μg/L之间,线性相关系数为0.9901~1.0000,检出限为0.0893~16.0414μg/L;该方法重复性相对标准偏差DRS均小于10.0%,精密度的DRS均小于7.1%,加样回收率为83.0%~117.5%,满足检测要求;在工艺流程中,朱砂的可溶性重金属含量呈逐步降低趋势,参照《药用植物及制剂进出口绿色行业标准》的限量标准,仅有H-5的Cd超出标准及H-3,H-4和H-5样品的Pb超出标准;仿生提取-ICP-OES法简单、快速,准确性及精度高,能够通过同时检测朱砂加工工艺过程中13种可溶性重金属含量检测,为实时监控朱砂加工工艺质量提供参考依据,有助于完善并确定最佳的朱砂生产加工流程。%Cinnabar samples with different processes in production and processing process were collected. Soluble heavy metals in cinnabaris were determined in the process of production and processing by inductively coupled plasma-optical emission spectrometry(ICP-OES) with bionic extraction and microwave digestion technology. The results show that 13 kinds of elements have excellent linearity over the range of 0.1−1 000.0 μg/L with a correlation coefficient of 0.990 1−1.000 0. Limits of detection are in the range of 0.089 3−16.041 4μg/L. Relative standard deviation DRS of the repeatability is less than 10.0%. DRS of precision is lower than 7.1%. Spike recoveries in the range of 83.0%−117.5%are obtained. In the process, the content of soluble heavy metals’ gradually reduces. With reference to green trade standards of importing&exporting medicinal plants&preparations, none of the samples surpass the legal limit for

  15. Determination of five kinds of trace elements in hogwash oil by microwave digestion-atomic absorption spectrometry%微波消解-原子吸收光谱法测定地沟油中5种微量元素

    Institute of Scientific and Technical Information of China (English)

    陈少永; 陶兆林; 张翊; 薛洪宝

    2015-01-01

    Objective:To explore the differences of five kinds of trace elements between edible cooking oil and hogwash oil. Methods:Different kinds of 5 parts edible oil and 1 part homemade lard oil,3 parts old cooking oil and 3 parts hogwash oil were collected. In each sample,0. 3 ~ 0. 4 g was weighed accurately. The samples were digested into a solution for determination by microwave. The contents of copper( Cu) ,zinc( Zn) ,manganese( Mn) ,lead( Pb) and iron( Fe) were determined by atomic absorption spectrometry. Results:In the experimental concentration range,the recovery rate was between 97. 6% to 102. 4%,the relative average deviation was 0. 6% to 2. 5%. The contents of 5 kinds of trace elements in old cooking oil were similar to soybean oil,and there had no differences of Cu,Zn,Mn and Pb contents between the edible oil and hogwash oil,whereas Fe content in old cooking oil and hogwash oil was higher than that in the edible oil(P<0. 01). Conclusions:There had no statistical differences of elements Cu,Zn,Mn and Pb contents between the edible oil and hogwash oil. Fe content was increased in hogwash oil,which may be due to the long-term exposure to the iron products when the hogwash oil was refined and transported.%目的::探讨地沟油与食用油中5种微量元素之间的差别。方法:选取不同种类的食用油5份和自制猪油1份(均称食用油),收集地沟油和煎炸老油各3份,准确称取各样品0.3~0.4 g,采用微波消解法制成可供测定的溶液,用原子吸收光谱法测定铜(Cu)、锌(Zn)、锰(Mn)、铅(Pb)和铁(Fe)的含量。结果:在实验选定浓度范围内,5种微量元素回收率为97.6%~102.4%,相对标准偏差为0.6%~2.5%。煎炸老油中5种微量元素的含量和大豆油相近;6种食用油中Cu、Zn、Mn和Pb的含量与地沟油差别不大;地沟油和煎炸老油中Fe的含量比6种食用油高(P<0.01)。结论:地沟油中Cu、Zn、Mn、Pb元素含量与食用油的含量差别不大,而Fe元素含

  16. The Cosmic Microwave Background

    OpenAIRE

    Silk, Joseph

    2002-01-01

    This set of lectures provides an overview of the basic theory and phenomenology of the cosmic microwave background. Topics include a brief historical review; the physics of temperature and polarization fluctuations; acoustic oscillations of the primordial plasma; the space of inflationary cosmological models; current and potential constraints on these models from the microwave background; and constraints on inflation.

  17. Microwave Enhanced Reactive Distillation

    NARCIS (Netherlands)

    Altman, E.

    2011-01-01

    The application of electromagnetic irradiation in form of microwaves (MW) has gathered the attention of the scientific community in recent years. MW used as an alternative energy source for chemical syntheses (microwave chemistry) can provide clear advantages over conventional heating methods in ter

  18. Incrust technology. Procedure for production of animal feeds encapsulated in a digestible shell. Phase 1. User economy; Fremgangsmaede for produktion af foder indkapslet i en fordoejelig skal. Fase 1. Brugeroekonomi

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-12-01

    More than 120 million tons animal feeds are produced within the European Union a year Denmark alone produces more than 6 million tons. Current industrial production of animal feeds implies different problems. This project aims at reducing or removing the following problems: Odour nuisances; Bacterium, especially salmonella; Nutrition, especially preservation of the animal feeds' natural elements; Energy, especially reduction of carbon dioxide emission; Independence of raw materials composition; Improved hygienic storage of the finished product. During the project a new method for production of animal feeds encapsulated in a digestible shell (feeding blocks) has been developed. Extruded feeding stuff is lead from an extruder to a common die, in which a shell pipe is formed vertically. Shape, diameter, and pipe thickness can be changed by adjustment of a set of nozzles. The shell pipe is lead to a cutter that shortens and closes one end. The shell pipe is now filled with the core product (feed mixture) from a feeder with a dosing screw. The quantity can be adjusted to the size of the feeding block by changing the number of the dosing screw's revolutions and the rotation speed. When the core product has been dosed into the shell pipe a shortening device shortens and closes the open end of the feeding block. The shortening device can be regulated so that make the feeding block form a line that is broken later in the process. If necessary a conveyor belt with condensate ventilation takes a number of feeding blocks in a line to a marker. Marks on the feeding blocks can be made with either a laser printer or an ink jet printer. (BA)

  19. Incrust technology. Procedure for production of animal feeds encapsulated in a digestible shell. Phase 4.0. Labelling; Incrust Technology. Fremgangsmaede for produktion af foder indkapslet i en fordoejelig skal. Fase 4.0. Maerkning

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-12-01

    More than 120 million tons animal feeds are produced within the European Union a year Denmark alone produces more than 6 million tons. Current industrial production of animal feeds implies different problems. This project aims at reducing or removing the following problems: Odour nuisances; Bacterium, especially salmonella; Nutrition, especially preservation of the animal feeds' natural elements; Energy, especially reduction of carbon dioxide emission; Independence of raw materials composition; Improved hygienic storage of the finished product. During the project a new method for production of animal feeds encapsulated in a digestible shell (feeding blocks) has been developed. Extruded feeding stuff is lead from an extruder to a common die, in which a shell pipe is formed vertically. Shape, diameter, and pipe thickness can be changed by adjustment of a set of nozzles. The shell pipe is lead to a cutter that shortens and closes one end. The shell pipe is now filled with the core product (feed mixture) from a feeder with a dosing screw. The quantity can be adjusted to the size of the feeding block by changing the number of the dosing screw's revolutions and the rotation speed. When the core product has been dosed into the shell pipe a shortening device shortens and closes the open end of the feeding block. The shortening device can be regulated so that make the feeding block form a line that is broken later in the process. If necessary a conveyor belt with condensate ventilation takes a number of feeding blocks in a line to a marker. Marks on the feeding blocks can be made with either a laser printer or an ink jet printer. (BA)

  20. Incrust technology. Procedure for production of fodder enclosed in a digestible shell. Processing plant - Plant construction; Incrust technology. Fremgangsmaede for produktion af foder indkapslet i en fordoejelig skal. Procesanlaeg - Anlaegsopbygning

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-12-01

    More than 120 million tons animal feeds are produced within the European Union a year Denmark alone produces more than 6 million tons. Current industrial production of animal feeds implies different problems. This project aims at reducing or removing the following problems: Odour nuisances; Bacterium, especially salmonella; Nutrition, especially preservation of the animal feeds' natural elements; Energy, especially reduction of carbon dioxide emission; Independence of raw materials composition; Improved hygienic storage of the finished product. During the project a new method for production of animal feeds encapsulated in a digestible shell (feeding blocks) has been developed. Extruded feeding stuff is lead from an extruder to a common die, in which a shell pipe is formed vertically. Shape, diameter, and pipe thickness can be changed by adjustment of a set of nozzles. The shell pipe is lead to a cutter that shortens and closes one end. The shell pipe is now filled with the core product (feed mixture) from a feeder with a dosing screw. The quantity can be adjusted to the size of the feeding block by changing the number of the dosing screw's revolutions and the rotation speed. When the core product has been dosed into the shell pipe a shortening device shortens and closes the open end of the feeding block. The shortening device can be regulated so that make the feeding block form a line that is broken later in the process. If necessary a conveyor belt with condensate ventilation takes a number of feeding blocks in a line to a marker. Marks on the feeding blocks can be made with either a laser printer or an ink jet printer. (BA)

  1. Incrust technology. Procedure for production of animal feeds encapsulated in a digestible shell. Phase 3.0. Shortening device; Incrust Technology. Fremgangsmaede for produktion af foder indkapslet i en fordoejelig skal. Fase 3.0. Afkorter

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-09-01

    More than 120 million tons animal feeds are produced within the European Union a year Denmark alone produces more than 6 million tons. Current industrial production of animal feeds implies different problems. This project aims at reducing or removing the following problems: Odour nuisances; Bacterium, especially salmonella; Nutrition, especially preservation of the animal feeds' natural elements; Energy, especially reduction of carbon dioxide emission; Independence of raw materials composition; Improved hygienic storage of the finished product. During the project a new method for production of animal feeds encapsulated in a digestible shell (feeding blocks) has been developed. Extruded feeding stuff is lead from an extruder to a common die, in which a shell pipe is formed vertically. Shape, diameter, and pipe thickness can be changed by adjustment of a set of nozzles. The shell pipe is lead to a cutter that shortens and closes one end. The shell pipe is now filled with the core product (feed mixture) from a feeder with a dosing screw. The quantity can be adjusted to the size of the feeding block by changing the number of the dosing screw's revolutions and the rotation speed. When the core product has been dosed into the shell pipe a shortening device shortens and closes the open end of the feeding block. The shortening device can be regulated so that make the feeding block form a line that is broken later in the process. If necessary a conveyor belt with condensate ventilation takes a number of feeding blocks in a line to a marker. Marks on the feeding blocks can be made with either a laser printer or an ink jet printer. (BA)

  2. Incrust technology. Procedure for production of animal feeds encapsulated in a digestible shell. Phase 2.2. Centre feeding; Incrust technology. Fremgangsmaede for produktion af foder indkapslet i en fordoejelig skal. Fase 2.2. Centerfoedning

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-10-01

    More than 120 million tons animal feeds are produced within the European Union a year Denmark alone produces more than 6 million tons. Current industrial production of animal feeds implies different problems. This project aims at reducing or removing the following problems: Odour nuisances; Bacterium, especially salmonella; Nutrition, especially preservation of the animal feeds' natural elements; Energy, especially reduction of carbon dioxide emission; Independence of raw materials composition; Improved hygienic storage of the finished product. During the project a new method for production of animal feeds encapsulated in a digestible shell (feeding blocks) has been developed. Extruded feeding stuff is lead from an extruder to a common die, in which a shell pipe is formed vertically. Shape, diameter, and pipe thickness can be changed by adjustment of a set of nozzles. The shell pipe is lead to a cutter that shortens and closes one end. The shell pipe is now filled with the core product (feed mixture) from a feeder with a dosing screw. The quantity can be adjusted to the size of the feeding block by changing the number of the dosing screw's revolutions and the rotation speed. When the core product has been dosed into the shell pipe a shortening device shortens and closes the open end of the feeding block. The shortening device can be regulated so that make the feeding block form a line that is broken later in the process. If necessary a conveyor belt with condensate ventilation takes a number of feeding blocks in a line to a marker. Marks on the feeding blocks can be made with either a laser printer or an ink jet printer. (BA)

  3. Application of Intermittent Microwave Irradiation to Western Blot Analysis.

    Science.gov (United States)

    Liu, Yu-Ting; Toyokuni, Shinya

    2015-01-01

    We established a shortened protocol for Western blot analysis using intermittent microwave irradiation. With this method, the procedure is completed within 1 h after applying the primary antibody, and thus greatly saves time. This procedure appears to be applicable to any antibody based on our experience of several years.

  4. Enhancing solubilisation and methane production kinetic of switchgrass by microwave pretreatment.

    Science.gov (United States)

    Jackowiak, D; Frigon, J C; Ribeiro, T; Pauss, A; Guiot, S

    2011-02-01

    This study investigated the effects of microwave pretreatment of switchgrass in order to enhance its anaerobic digestibility. Response surface analysis was applied to screen the effects of temperature and time of microwave pretreatment on matter solubilisation. The composite design showed that only temperature had a significant effect on solubilisation level. Then the effects of the microwave pretreatment were correlated to the pretreatment temperature. The sCOD/tCOD ratio was equal to 9.4% at 90°C and increased until 13.8% at 180°C. The BMP assays of 42 days showed that microwave pretreatment induced no change on the ultimate volume of methane but had an interesting effect on the reaction kinetic. Indeed, the time required to reach 80% of ultimate volume CH(4) is reduced by 4.5 days at 150°C using the microwave pretreatment.

  5. Clinical Application of Stents in Digestive Diseases

    Institute of Scientific and Technical Information of China (English)

    GUAN Yongsong

    2002-01-01

    Objective To evaluate clinical application of therapeutic stenting of digestive diseases as a new approach from conventional management. Methods 115 cases of disorders in digestive system were managed with stents clinically, 148 procedures of intervention in all. The cases were suffering from portal hypertension of cirrhosis, post - operative esophageal stricture, Stricture resulted from esophageal carcinoma, Buddi - Chari syndrome, narrowing of superior mesentery arteries and biliary tract, etc. All had had the strictured or obliterated original natural tube lumen been dilated or recanalized under the guidance of monitoring of the fluoroscope before the stent placement except those receiving TIPS needing the creation of an artificial passage within the liver to place the stent. Results Therapeutic stenting achieves clinical effects completely different from conventional internal medicine and surgery such as portal hypertension by cirrhosis with esophageal varices, megalospleen, ascites improved; jaundis relived then resided and liver function improved and appetite better in postoperative stricture of bile duct; ascites and edema of lower limbs resided in Buddi - Chari syndrom; intestininal distention disappeared, appetite and digestive function improved in stricture in superior mesentery artery; and no dysphagia and easy food intake, appetite improved in patients of stricture of postoperative esophagus and stricture resulted from esophageal carcinoma. Conclusion Therapeutic stenting is clinically unique, dramatically effective, with minor risks and worthy promoting in the management of certain digestive disorders.

  6. Steam Digest Volume IV

    Energy Technology Data Exchange (ETDEWEB)

    None

    2004-07-01

    This edition of the Steam Digest is a compendium of 2003 articles on the technical and financial benefits of steam efficiency, presented by the stakeholders of the U.S. Department of Energy's BestPractices Steam effort.

  7. Bibliotherapy. ERIC Digest.

    Science.gov (United States)

    Abdullah, Mardziah Hayati

    This digest suggests that bibliotherapy is a potentially powerful method for school teachers and counselors to use on many levels and in every school grade. It begins with a brief review of the history of bibliotherapy; continues with a discussion of some approaches to bibliotherapy (interactive, clinical, and developmental); then addresses the…

  8. Anaerobic digestion without biogas?

    NARCIS (Netherlands)

    Kleerebezem, R.; Joosse, B.; Rozendaal, R.; Van Loosdrecht, M.C.M.

    2015-01-01

    Anaerobic digestion for the production of methane containing biogas is the classic example of a resource recovery process that combines stabilization of particulate organic matter or wastewater treatment with the production of a valuable end-product. Attractive features of the process include the pr

  9. The anaerobic digestion process

    Energy Technology Data Exchange (ETDEWEB)

    Rivard, C.J. [National Renewable Energy Lab., Golden, CO (United States); Boone, D.R. [Oregon Graduate Inst., Portland, OR (United States)

    1996-01-01

    The microbial process of converting organic matter into methane and carbon dioxide is so complex that anaerobic digesters have long been treated as {open_quotes}black boxes.{close_quotes} Research into this process during the past few decades has gradually unraveled this complexity, but many questions remain. The major biochemical reactions for forming methane by methanogens are largely understood, and evolutionary studies indicate that these microbes are as different from bacteria as they are from plants and animals. In anaerobic digesters, methanogens are at the terminus of a metabolic web, in which the reactions of myriads of other microbes produce a very limited range of compounds - mainly acetate, hydrogen, and formate - on which the methanogens grow and from which they form methane. {open_quotes}Interspecies hydrogen-transfer{close_quotes} and {open_quotes}interspecies formate-transfer{close_quotes} are major mechanisms by which methanogens obtain their substrates and by which volatile fatty acids are degraded. Present understanding of these reactions and other complex interactions among the bacteria involved in anaerobic digestion is only now to the point where anaerobic digesters need no longer be treated as black boxes.

  10. Anaerobic digestion without biogas?

    NARCIS (Netherlands)

    Kleerebezem, R.; Joosse, B.; Rozendaal, R.; Van Loosdrecht, M.C.M.

    2015-01-01

    Anaerobic digestion for the production of methane containing biogas is the classic example of a resource recovery process that combines stabilization of particulate organic matter or wastewater treatment with the production of a valuable end-product. Attractive features of the process include the

  11. Anaerobic digestion without biogas?

    NARCIS (Netherlands)

    Kleerebezem, R.; Joosse, B.; Rozendaal, R.; Van Loosdrecht, M.C.M.

    2015-01-01

    Anaerobic digestion for the production of methane containing biogas is the classic example of a resource recovery process that combines stabilization of particulate organic matter or wastewater treatment with the production of a valuable end-product. Attractive features of the process include the pr

  12. Influência de métodos de digestão e massa de amostra na recuperação de nutrientes em resíduos orgânicos Influence of digestion method and sample mass on the recovery of nutrients in organic residues

    Directory of Open Access Journals (Sweden)

    Leônidas Carrijo Azevedo Melo

    2008-01-01

    Full Text Available The influence of nitric-perchloric, aqua regia, dry ashing and microwave digestion methods, in combination with 100 and 200 mg of sample, on the characterization and recovery of nutrients in samples of sludge sewage, poultry, swine, quail and bovine manures, organic compost, organic substrate and humic material were studied. Nitric-perchloric digestion with 200 mg samples recovered the higher nutrient contents. The nitric-perchloric method recovered also low levels of K. Dry ashing caused S volatilization and microwave digestion produced dark color extracts and this impaired S determination. Aqua regia recovered the lowest contents of nutrients in the organic residues evaluated.

  13. The microwave absorption of ceramic-cup microwave ion source

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    An experiment system of ceramic-cup microwave ion source has been built here. Its microwave absorption efficiency as a function of the magnetic field and the pressure is presented. When the microwave incident power is 300~500W the microwave absorption efficiencies are more than 90% if the system is optimized and the magnetic field at the microwave window is 0.095T.

  14. Gold Nanoparticle Microwave Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Krantz, Kelsie E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Christian, Jonathan H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Coopersmith, Kaitlin [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Washington, II, Aaron L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Murph, Simona H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-07-27

    At the nanometer scale, numerous compounds display different properties than those found in bulk material that can prove useful in areas such as medicinal chemistry. Gold nanoparticles, for example, display promise in newly developed hyperthermia therapies for cancer treatment. Currently, gold nanoparticle synthesis is performed via the hot injection technique which has large variability in final particle size and a longer reaction time. One underdeveloped area by which these particles could be produced is through microwave synthesis. To initiate heating, microwaves agitate polar molecules creating a vibration that gives off the heat energy needed. Previous studies have used microwaves for gold nanoparticle synthesis; however, polar solvents were used that partially absorbed incident microwaves, leading to partial thermal heating of the sample rather than taking full advantage of the microwave to solely heat the gold nanoparticle precursors in a non-polar solution. Through this project, microwaves were utilized as the sole heat source, and non-polar solvents were used to explore the effects of microwave heating only as pertains to the precursor material. Our findings show that the use of non-polar solvents allows for more rapid heating as compared to polar solvents, and a reduction in reaction time from 10 minutes to 1 minute; this maximizes the efficiency of the reaction, and allows for reproducibility in the size/shape of the fabricated nanoparticles.

  15. Gold Nanoparticle Microwave Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Krantz, Kelsie E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Christian, Jonathan H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Coopersmith, Kaitlin [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Washington, II, Aaron L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Murph, Simona H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-07-27

    At the nanometer scale, numerous compounds display different properties than those found in bulk material that can prove useful in areas such as medicinal chemistry. Gold nanoparticles, for example, display promise in newly developed hyperthermia therapies for cancer treatment. Currently, gold nanoparticle synthesis is performed via the hot injection technique which has large variability in final particle size and a longer reaction time. One underdeveloped area by which these particles could be produced is through microwave synthesis. To initiate heating, microwaves agitate polar molecules creating a vibration that gives off the heat energy needed. Previous studies have used microwaves for gold nanoparticle synthesis; however polar solvents were used that partially absorbed incident microwaves, leading to partial thermal heating of the sample rather than taking full advantage of the microwave to solely heat the gold nanoparticle precursors in a non-polar solution. Through this project, microwaves were utilized as the sole heat source, and non-polar solvents were used to explore the effects of microwave heating only as pertains to the precursor material. Our findings show that the use of non-polar solvents allows for more rapid heating as compared to polar solvents, a reduction in reaction time from 10 minutes to 1 minute, maximizes the efficiency of the reaction, and allows for reproducibility in the size/shape of the fabricated nanoparticles.

  16. Microwave-assisted isomerisation of lactose to lactulose and Maillard conjugation of lactulose and lactose with whey proteins and peptides.

    Science.gov (United States)

    Nooshkam, Majid; Madadlou, Ashkan

    2016-06-01

    Lactose was isomerised to lactulose by microwave heating and purified by a methanolic procedure to a product with approximately 72% lactulose content. Afterwards, lactose and the lactulose-rich product (PLu) were conjugated with either whey protein isolate (WPI) or its antioxidant hydrolysate (WPH) through microwaving. Lactose had a higher Maillard reactivity than PLu, and WPH was more reactive than WPI. The browning intensity of WPI-sugar systems was however higher than that of WPH-sugar pairs. Atomic force microscopy showed larger (up to ≈103 nm) particles for WPI-PLu conjugates compared to WPH-PLu counterparts (up to ≈39 nm). The Maillard conjugation progressively increased the radical-scavenging activity of WPI/WPH-sugar pairs with increasing conjugation time and improved the foaming properties of WPI and WPH. The WPI/WPH-sugar conjugates showed higher solubility and emulsification index than unreacted counterpart pairs. For native WPI, β-lactoglobulin was not degraded by in vitro gastric digestion, whereas for WPH-PLu conjugates degraded completely.

  17. Phosphorus and heavy metal extraction from wastewater treatment plant sludges using microwaves for generation of exceptional quality biosolids.

    Science.gov (United States)

    Danesh, Paymon; Hong, Seung M; Moon, Kyong W; Park, Jae K

    2008-09-01

    The objectives of this study were to evaluate the amount of phosphorus and metals in sludge that can be released into solution by microwave irradiation when applied to sludge before anaerobic digestion and determine the effectiveness of subsequent lime precipitation. The fraction of phosphorus in the soluble form increased to 23 to 28% for thickened sludge and to 31 to 38% for unthickened sludge, after raising temperatures by microwave heating to 50 to 70 degrees C. Microwave irradiation also caused the release of arsenic, molybdenum, nickel, and selenium into solution to 33, 15, 13, and 28% for thickened sludge and 63, 61, 37, and 27% for unthickened sludge, respectively. Microwave irradiation has been found to destruct pathogens in sludge to meet Class A biosolids requirements. Therefore, the reduction of phosphorus and metals in biosolids using microwave heating is economically attractive when considered as a secondary benefit to the use of microwave heating to generate Class A biosolids.

  18. Artificial color perception using microwaves

    OpenAIRE

    Choudhury, Debesh; Caulfield, H. John

    2013-01-01

    We report the feasibility of artificial color perception under microwave illumination using a standard microwave source and an antenna. We have sensed transmitted microwave power through color objects and have distinguished the colors by analyzing the sensed transmitted power. Experiments are carried out using a Gunn diode as the microwave source, some colored liquids as the objects and a microwave diode as the detector. Results are presented which open up an unusual but new way of perceiving...

  19. Advances in microwaves 4

    CERN Document Server

    Young, Leo

    2013-01-01

    Advances in Microwaves, Volume 4 covers some innovations in the devices and applications of microwaves. This volume contains three chapters and begins with a discussion of the application of microwave phasers and time delay elements as beam steering elements in array radars. The next chapter provides first an overview of the technical aspects and different types of millimeter waveguides, followed by a survey of their application to railroads. The last chapter examines the general mode of conversion properties of nonuniform waveguides, such as waveguide tapers, using converted Maxwell's equatio

  20. Integrated microwave photonics

    CERN Document Server

    Marpaung, David; Heideman, Rene; Leinse, Arne; Sales, Salvador; Capmany, Jose

    2012-01-01

    Microwave photonics (MWP) is an emerging field in which radio frequency (RF) signals are generated, distributed, processed and analyzed using the strength of photonic techniques. It is a technology that enables various functionalities which are not feasible to achieve only in the microwave domain. A particular aspect that recently gains significant interests is the use of photonic integrated circuit (PIC) technology in the MWP field for enhanced functionalities and robustness as well as the reduction of size, weight, cost and power consumption. This article reviews the recent advances in this emerging field which is dubbed as integrated microwave photonics. Key integrated MWP technologies are reviewed and the prospective of the field is discussed.

  1. Advances in microwaves

    CERN Document Server

    Young, Leo

    1967-01-01

    Advances in Microwaves, Volume 2 focuses on the developments in microwave solid-state devices and circuits. This volume contains six chapters that also describe the design and applications of diplexers and multiplexers. The first chapter deals with the parameters of the tunnel diode, oscillators, amplifiers and frequency converter, followed by a simple physical description and the basic operating principles of the solid state devices currently capable of generating coherent microwave power, including transistors, harmonic generators, and tunnel, avalanche transit time, and diodes. The next ch

  2. The Microwave Hall Effect

    OpenAIRE

    2015-01-01

    This paper describes a simple microwave apparatus to measure the Hall effect in semiconductor wafers. The advantage of this technique is that it does not require contacts on the sample or the use of a resonant cavity. Our method consists of placing the semiconductor wafer into a slot cut in an X-band (8 - 12 GHz) waveguide series tee, injecting microwave power into the two opposite arms of the tee, and measuring the microwave output at the third arm. A magnetic field applied perpendicular to ...

  3. Monolithic microwave integrated circuits

    Science.gov (United States)

    Pucel, R. A.

    Monolithic microwave integrated circuits (MMICs), a new microwave technology which is expected to exert a profound influence on microwave circuit designs for future military systems as well as for the commercial and consumer markets, is discussed. The book contains an historical discussion followed by a comprehensive review presenting the current status in the field. The general topics of the volume are: design considerations, materials and processing considerations, monolithic circuit applications, and CAD, measurement, and packaging techniques. All phases of MMIC technology are covered, from design to testing.

  4. Food microstructure and starch digestion.

    Science.gov (United States)

    Singh, Jaspreet; Kaur, Lovedeep; Singh, Harjinder

    2013-01-01

    Microstructural characteristics of starch-based natural foods such as parenchyma or cotyledon cell shape, cell size and composition, and cell wall composition play a key role in influencing the starch digestibility during gastrointestinal digestion. The stability of cell wall components and the arrangement of starch granules in the cells may affect the free access of amylolytic enzymes during digestion. Commonly used food processing techniques such as thermal processing, extrusion cooking, and post-cooking refrigerated storage alter the physical state of starch (gelatinization, retrogradation, etc.) and its digestibility. Rheological characteristics (viscosity) of food affect the water availability during starch hydrolysis and, consequently, the absorption of digested carbohydrates in the gastrointestinal tract. The nonstarch ingredients and other constituents present in food matrix, such as proteins and lipids interact with starch during processing, which leads to an alteration in the overall starch digestibility and physicochemical characteristics of digesta. Starch digestibility can be controlled by critically manipulating the food microstructure, processing techniques, and food composition.

  5. Tail regeneration affects the digestive performance of a Mediterranean lizard

    Science.gov (United States)

    Sagonas, Kostas; Karambotsi, Niki; Bletsa, Aristoula; Reppa, Aikaterini; Pafilis, Panayiotis; Valakos, Efstratios D.

    2017-04-01

    In caudal autotomy, lizards shed their tail to escape from an attacking predator. Since the tail serves multiple functions, caudal regeneration is of pivotal importance. However, it is a demanding procedure that requires substantial energy and nutrients. Therefore, lizards have to increase energy income to fuel the extraordinary requirements of the regenerating tail. We presumed that autotomized lizards would adjust their digestion to acquire this additional energy. To clarify the effects of tail regeneration on digestion, we compared the digestive performance before autotomy, during regeneration, and after its completion. Tail regeneration indeed increased gut passage time but did not affect digestive performance in a uniform pattern: though protein income was maximized, lipid and sugar acquisition remained stable. This divergence in proteins may be attributed to their particular role in tail reconstruction, as they are the main building blocks for tissue formation.

  6. Microwave Service Towers

    Data.gov (United States)

    Department of Homeland Security — This file is an extract of the Universal Licensing System (ULS) licensed by the Wireless Telecommunications Bureau (WTB). It consists of Microwave Transmitters (see...

  7. Microwave Radiometer Profiler

    Data.gov (United States)

    Oak Ridge National Laboratory — The microwave radiometer profiler (MWRP) provides vertical profiles of temperature, humidity, and cloud liquid water content as a function of height or pressure at...

  8. Microwave Oven Observations.

    Science.gov (United States)

    Sumrall, William J.; Richardson, Denise; Yan, Yuan

    1998-01-01

    Explains a series of laboratory activities which employ a microwave oven to help students understand word problems that relate to states of matter, collect data, and calculate and compare electrical costs to heat energy costs. (DDR)

  9. Microwave Oven Observations.

    Science.gov (United States)

    Sumrall, William J.; Richardson, Denise; Yan, Yuan

    1998-01-01

    Explains a series of laboratory activities which employ a microwave oven to help students understand word problems that relate to states of matter, collect data, and calculate and compare electrical costs to heat energy costs. (DDR)

  10. Microwave Radiometer - high frequency

    Data.gov (United States)

    Oak Ridge National Laboratory — The Microwave Radiometer-High Frequency (MWRHF) provides time-series measurements of brightness temperatures from two channels centered at 90 and 150 GHz. These two...

  11. Microwave workshop for Windows

    Directory of Open Access Journals (Sweden)

    Colin White

    1995-12-01

    Full Text Available A suite of three programs has been developed to support the teaching of microwave theory and design. A secondary function of the package is to support microwave engineers by providing a library of utilities to assist their design function. All three programs were written in Visual Basic and are aimed at supporting both tutor-directed and student-centred learning methodologies. The development team consisted of three final-year degree students.

  12. Microwave system engineering principles

    CERN Document Server

    Raff, Samuel J

    1977-01-01

    Microwave System Engineering Principles focuses on the calculus, differential equations, and transforms of microwave systems. This book discusses the basic nature and principles that can be derived from thermal noise; statistical concepts and binomial distribution; incoherent signal processing; basic properties of antennas; and beam widths and useful approximations. The fundamentals of propagation; LaPlace's Equation and Transmission Line (TEM) waves; interfaces between homogeneous media; modulation, bandwidth, and noise; and communications satellites are also deliberated in this text. This bo

  13. Anaerobic Digestion Foaming Causes

    OpenAIRE

    Ganidi, Nafsika

    2008-01-01

    Anaerobic digestion foaming has been encountered in several sewage treatment plants in the UK. Foaming has raised major concerns for the water utilities due to significant impacts on process efficiency and operational costs. Several foaming causes have been suggested over the past few years by researchers. However, the supporting experimental information is limited and in some cases site specific. The present report aimed to provide a better understanding of the anaerobic di...

  14. Optimal acid digestion for multi-element analysis of different waste matrices

    DEFF Research Database (Denmark)

    Götze, Ramona; Astrup, Thomas Fruergaard

    in the Paper & Cardboard matrix and for 10 elements in the Composite matrix. The ranking procedure points to different methods to be the most optimal digestion methods in the tested waste matrices. The recovery rates can vary by more than 90% among the tested digestion methods depending on the individual...

  15. Characterization method of dielectric properties of free falling drops in a microwave processing cavity and its application in microwave internal gelation

    Science.gov (United States)

    Cabanes-Sempere, M.; Catalá-Civera, J. M.; Peñaranda-Foix, F. L.; Cozzo, C.; Vaucher, S.; Pouchon, M. A.

    2013-09-01

    Microwave internal gelation (MIG) is a chemical process proposed for the production of nuclear particle fuel. The internal gelation reaction is triggered by a temperature increase of aqueous droplets falling by gravity by means of non-contact microwave heating. Due to the short residence time of a solution droplet in a microwave heating cavity, a detailed knowledge of the interaction between microwaves and chemical solution (shaped in small drops) is required. This paper describes a procedure that enables the measurement of the dielectric properties of aqueous droplets that freely fall through a microwave cavity. These measurements provide the information to determine the optimal values of the parameters (such as frequency and power) that dictate the heating of such a material under microwaves.

  16. Monitoring digestibility of forages for herbivores: a new application for an old approach

    Science.gov (United States)

    VanSomeren, LIndsey L.; Barboza, Perry S.; Thompson, Daniel P.; Gustine, David D.

    2015-01-01

    Ruminant populations are often limited by how well individuals are able to acquire nutrients for growth, maintenance, and reproduction. Nutrient supply to the animal is dictated by the concentration of nutrients in feeds and the efficiency of digesting those nutrients (i.e., digestibility). Many different methods have been used to measure digestibility of forages for wild herbivores, all of which rely on collecting rumen fluid from animals or incubation within animals. Animal-based methods can provide useful estimates, but the approach is limited by the expense of fistulated animals, wide variation in digestibility among animals, and contamination from endogenous and microbial sources that impairs the estimation of nutrient digestibility. We tested an in vitro method using a two-stage procedure using purified enzymes. The first stage, a 6 h acid–pepsin treatment, was followed by a combined 72 h amylase–cellulase or amylase–Viscozyme treatment. We then validated our estimates using in sacco and in vivo methods to digest samples of the same forages. In vitro estimates of dry matter (DM) digestibility were correlated with estimates of in sacco and in vivo DM digestibility (both P < 0.01). The in vitro procedure using Viscozyme (r2 = 0.77) was more precise than the in vitro procedure using cellulase (r2 = 0.59). Both procedures can be used to predict in sacco digestibility after correcting for the biases of each method. We used the in vitro method to measure digestibility of nitrogen (N; 0.07–0.95 g/g), which declined to zero as total N content declined below 0.03–0.06 g/g of DM. The in vitro method is well suited to monitoring forage quality over multiple years because it is reproducible, can be used with minimal investment by other laboratories without animal facilities, and can measure digestibility of individual nutrients such as N.

  17. Microwave assisted alkaline pretreatment to enhance enzymatic saccharification of catalpa sawdust.

    Science.gov (United States)

    Jin, Shuguang; Zhang, Guangming; Zhang, Panyue; Li, Fan; Wang, Siqi; Fan, Shiyang; Zhou, Shuqiong

    2016-12-01

    Catalpa sawdust, a promising biofuel production biomass, was pretreated by microwave-water, -NaOH, and -Ca(OH)2 to enhance enzymatic digestibility. After 48h enzymatic hydrolysis, microwave-Ca(OH)2 pretreated sample showed the highest reducing sugar yield. The content of hemicellulose and lignin in catalpa sawdust decreased after microwave-alkali pretreatment. SEM observation showed that the catalpa sawdust surface with microwave-Ca(OH)2 pretreatment suffered the most serious erosion. Crystallinity index of catalpa sawdust increased after all three kinds of pretreatment. The optimum conditions of microwave-Ca(OH)2 pretreatment were particle size of 40mesh, Ca(OH)2 dosage of 2.25% (w/v), microwave power of 400W, pretreatment time of 6min, enzyme loading of 175FPU/g, and hydrolysis time of 96h, and the reducing sugar yield of microwave-Ca(OH)2 pretreated catalpa sawdust reached 402.73mg/g, which increased by 682.15% compared with that of raw catalpa sawdust. The catalpa sawdust with microwave-Ca(OH)2 pretreatment is promising for biofuel production with great potential.

  18. Microwave synthesis of Titanium Dioxide nanotubes for use in water treatment

    CSIR Research Space (South Africa)

    Sikhwivhilu, L

    2010-09-01

    Full Text Available during hydrothermal processing2,3. In our study, TiO2 nanostructures are synthesised using conventional heating and microwave-assisted hydrothermal procedure. The effects of heating on the size, shape and crystallinity of materials are studied. Microwave...

  19. Economic viability of anaerobic digestion

    Energy Technology Data Exchange (ETDEWEB)

    Wellinger, A. [INFOENERGIE, Ettenhausen (Switzerland)

    1996-01-01

    The industrial application of anaerobic digestion is a relatively new, yet proven waste treatment technology. Anaerobic digestion reduces and upgrades organic waste, and is a good way to control air pollution as it reduces methane and nitrous gas emissions. For environmental and energy considerations, anaerobic digestion is a nearly perfect waste treatment process. However, its economic viability is still in question. A number of parameters - type of waste (solid or liquid), digester system, facility size, product quality and end use, environmental requirements, cost of alternative treatments (including labor), and interest rates - define the investment and operating costs of an anaerobic digestion facility. Therefore, identical facilities that treat the same amount and type of waste may, depending on location, legislation, and end product characteristics, reveal radically different costs. A good approach for evaluating the economics of anaerobic digestion is to compare it to treatment techniques such as aeration or conventional sewage treatment (for industrial wastewater), or composting and incineration (for solid organic waste). For example, the cost (per ton of waste) of in-vessel composting with biofilters is somewhat higher than that of anaerobic digestion, but the investment costs 1 1/2 to 2 times more than either composting or anaerobic digestion. Two distinct advantages of anaerobic digestion are: (1) it requires less land than either composting or incinerating, which translates into lower costs and milder environmental and community impacts (especially in densely populated areas); and (2) it produces net energy, which can be used to operate the facility or sold to nearby industries.

  20. Digestive health in pregnancy.

    Science.gov (United States)

    Kenyon, Charlotte

    2014-10-01

    Women experience the physiological changes of pregnancy in a variety of ways. Changes in pregnancy are associated with changing hormone levels. These hormonal changes have an impact on all body systems. Midwives need to have an understanding of the changes so that they can enable women to manage their digestive health effectively. The midwife needs to be vigilant in history taking to understand the woman's experiences and to be able to offer appropriate support and advice. There are a number of conventional and alternative treatments that can help to prevent and alleviate symptoms. This article will consider the impact on the gastro-intestinal system and how changes can be managed.

  1. Anomalous Microwave Emission

    CERN Document Server

    Kogut, A J

    1999-01-01

    Improved knowledge of diffuse Galactic emission is important to maximize the scientific return from scheduled CMB anisotropy missions. Cross-correlation of microwave maps with maps of the far-IR dust continuum show a ubiquitous microwave emission component whose spatial distribution is traced by far-IR dust emission. The spectral index of this emission, beta_{radio} = -2.2 (+0.5 -0.7) is suggestive of free-free emission but does not preclude other candidates. Comparison of H-alpha and microwave results show that both data sets have positive correlations with the far-IR dust emission. Microwave data, however, are consistently brighter than can be explained solely from free-free emission traced by H-alpha. This ``anomalous'' microwave emission can be explained as electric dipole radiation from small spinning dust grains. The anomalous component at 53 GHz is 2.5 times as bright as the free-free emission traced by H-alpha, providing an approximate normalization for models with significant spinning dust emission.

  2. Microwave engineering concepts and fundamentals

    CERN Document Server

    Khan, Ahmad Shahid

    2014-01-01

    Detailing the active and passive aspects of microwaves, Microwave Engineering: Concepts and Fundamentals covers everything from wave propagation to reflection and refraction, guided waves, and transmission lines, providing a comprehensive understanding of the underlying principles at the core of microwave engineering. This encyclopedic text not only encompasses nearly all facets of microwave engineering, but also gives all topics—including microwave generation, measurement, and processing—equal emphasis. Packed with illustrations to aid in comprehension, the book: •Describes the mathematical theory of waveguides and ferrite devices, devoting an entire chapter to the Smith chart and its applications •Discusses different types of microwave components, antennas, tubes, transistors, diodes, and parametric devices •Examines various attributes of cavity resonators, semiconductor and RF/microwave devices, and microwave integrated circuits •Addresses scattering parameters and their properties, as well a...

  3. Highlights of pancreatobiliary endoscopy in international digestive endoscopy network 2012: how much has it advanced?

    Science.gov (United States)

    Dong, Seok Ho

    2012-09-01

    The pancreatobiliary organ is composed of one of the most complicated structures and complex physiological functions among other digestive organs in our body. This is why endoscopic procedure in pancreaticobiliary system requires rather complicated techniques. In International Digestive Endoscopy Network (IDEN) 2012, many interesting pancreatobiliay endoscopy related topics were presented. Basic procedures like endoscopic papillary balloon dilation (EPBD), advanced techniques like endoscopic necrosectomy, prevention and management of post-ERCP pancreatitis, and spyglass system are reviewed in this highlight summary.

  4. Cosmic Microwave Background Mapping

    Science.gov (United States)

    Verkhodanov, O. V.; Doroshkevich, A. G.

    2012-03-01

    The last decade of research in cosmology was connected with the ambitious experiments including space and ground base observations. Among the most impressive results of these investigations are the measurements of the cosmic microwave background (CMB) radiation like WMAP* and Planck. Exactly from the CMB studies, we have started the epoch of the precision cosmology when generally the values of cosmological parameters have been known and present research is devoted to improvement of the precision. These achievements are connected with both the creation of the new facilities in millimeter and submillimeter astronomy (e.g., satellites, receivers, antennas, computers) and development of the methods for the CMB data analysis. Actually, the process of data analysis contains several technical stages including 1. Registration of time-ordered data (TOD) 2. Pixelization of the CMB data - map preparation 3. Component separation 4. Map statistics analysis 5. Map - spherical harmonics transformation 6. C(l)-spectrum calculation and spectrum statistics analysis 7. Cosmological parameters estimation Starting from the cosmic background explorer (COBE) experiment using the so-called Quadrilateralized Sky Cube Projection (see [1-3]), the problem of the whole sky CMB pixelization has attracted great interest and many such schemes were developed. Let us note however that accurate pixelization of the CMB data on the sphere is very important but not the final step of analysis. Usually, the next step implies the determination of the coefficients of the spherical harmonic decomposition of the CMB signal for both anisotropy and polarization. This means that some of the pixelization schemes provide a very accurate map but are inconvenient for further decomposition. This also means that the choice of suitable pixelization schemes depends upon the general goals of the investigation. In this review, we consider several of the most popular sky map pixelization schemes and link them with the

  5. High power microwaves

    CERN Document Server

    Benford, James; Schamiloglu, Edl

    2016-01-01

    Following in the footsteps of its popular predecessors, High Power Microwaves, Third Edition continues to provide a wide-angle, integrated view of the field of high power microwaves (HPMs). This third edition includes significant updates in every chapter as well as a new chapter on beamless systems that covers nonlinear transmission lines. Written by an experimentalist, a theorist, and an applied theorist, respectively, the book offers complementary perspectives on different source types. The authors address: * How HPM relates historically and technically to the conventional microwave field * The possible applications for HPM and the key criteria that HPM devices have to meet in order to be applied * How high power sources work, including their performance capabilities and limitations * The broad fundamental issues to be addressed in the future for a wide variety of source types The book is accessible to several audiences. Researchers currently in the field can widen their understanding of HPM. Present or pot...

  6. Microwave-assisted Chemical Transformations

    Science.gov (United States)

    In recent years, there has been a considerable interest in developing sustainable chemistries utilizing green chemistry principles. Since the first published report in 1986 by Gedye and Giguere on microwave assisted synthesis in household microwave ovens, the use of microwaves as...

  7. Physics of the Microwave Oven

    Science.gov (United States)

    Vollmer, Michael

    2004-01-01

    This is the first of two articles about the physics of microwave ovens. This article deals with the generation of microwaves in the oven and includes the operation of the magnetrons, waveguides and standing waves in resonant cavities. It then considers the absorption of microwaves by foods, discussing the dielectric relaxation of water,…

  8. Physics of the Microwave Oven

    Science.gov (United States)

    Vollmer, Michael

    2004-01-01

    This is the first of two articles about the physics of microwave ovens. This article deals with the generation of microwaves in the oven and includes the operation of the magnetrons, waveguides and standing waves in resonant cavities. It then considers the absorption of microwaves by foods, discussing the dielectric relaxation of water,…

  9. A microwave powered sensor assembly for microwave ovens

    DEFF Research Database (Denmark)

    2016-01-01

    The present invention relates to a microwave powered sensor assembly for micro- wave ovens. The microwave powered sensor assembly comprises a microwave antenna for generating an RF antenna signal in response to microwave radiation at a predetermined excitation frequency. A dc power supply circuit...... of the microwave powered sensor assembly is operatively coupled to the RF antenna signal for extracting energy from the RF antenna signal and produce a power supply voltage. A sensor is connected to the power supply voltage and configured to measure a physical or chemical property of a food item under heating...

  10. Microwave-assisted convenient synthesis of N-arylpyrrolidines in water

    Institute of Scientific and Technical Information of China (English)

    Hong Bo Li; Wu Liang; Lang Liu; Kai Chen; Yi Wu

    2011-01-01

    An efficient and clean synthesis of N-arylpyrrolidines from arylamines and 1,4-dimesyloxybutane was developed using microwave irradiation in an aqueous potassium carbonate medium without any catalyst. The procedure is rapid, simple and convenient.

  11. TEM and EELS studies of microwave-irradiation synthesis of bimetallic platinum nanocatalysts

    CSIR Research Space (South Africa)

    Mathe, NR

    2014-01-01

    Full Text Available Microwave-irradiation (MW) synthesis of nanostructured materials provides for the synthesis of metal nanoparticles, using fast and uniform heating rates. This procedure affords better control of the shape and size of the nanoparticles when compared...

  12. Microwave Tissue Soldering for Immediate Wound Closure

    Science.gov (United States)

    Arndt, G. Dickey; Ngo, Phong H.; Phan, Chau T.; Byerly, Diane; Dusl, John; Sognier, Marguerite A.; Carl, James

    2011-01-01

    A novel approach for the immediate sealing of traumatic wounds is under development. A portable microwave generator and handheld antenna are used to seal wounds, binding the edges of the wound together using a biodegradable protein sealant or solder. This method could be used for repairing wounds in emergency settings by restoring the wound surface to its original strength within minutes. This technique could also be utilized for surgical purposes involving solid visceral organs (i.e., liver, spleen, and kidney) that currently do not respond well to ordinary surgical procedures. A miniaturized microwave generator and a handheld antenna are used to deliver microwave energy to the protein solder, which is applied to the wound. The antenna can be of several alternative designs optimized for placement either in contact with or in proximity to the protein solder covering the wound. In either case, optimization of the design includes the matching of impedances to maximize the energy delivered to the protein solder and wound at a chosen frequency. For certain applications, an antenna could be designed that would emit power only when it is in direct contact with the wound. The optimum frequency or frequencies for a specific application would depend on the required depth of penetration of the microwave energy. In fact, a computational simulation for each specific application could be performed, which would then match the characteristics of the antenna with the protein solder and tissue to best effect wound closure. An additional area of interest with potential benefit that remains to be validated is whether microwave energy can effectively kill bacteria in and around the wound. Thus, this may be an efficient method for simultaneously sterilizing and closing wounds.

  13. Microwave Frequency Polarizers

    Science.gov (United States)

    Ha, Vien The; Mirel, Paul; Kogut, Alan J.

    2013-01-01

    This article describes the fabrication and analysis of microwave frequency polarizing grids. The grids are designed to measure polarization from the cosmic microwave background. It is effective in the range of 500 to 1500 micron wavelength. It is cryogenic compatible and highly robust to high load impacts. Each grid is fabricated using an array of different assembly processes which vary in the types of tension mechanisms to the shape and size of the grids. We provide a comprehensive study on the analysis of the grids' wire heights, diameters, and spacing.

  14. Microwave Discharge Ion Sources

    CERN Document Server

    Celona, L

    2013-01-01

    This chapter describes the basic principles, design features and characteristics of microwave discharge ion sources. A suitable source for the production of intense beams for high-power accelerators must satisfy the requirements of high brightness, stability and reliability. The 2.45 GHz off-resonance microwave discharge sources are ideal devices to generate the required beams, as they produce multimilliampere beams of protons, deuterons and singly charged ions. A description of different technical designs will be given, analysing their performance, with particular attention being paid to the quality of the beam, especially in terms of its emittance.

  15. Fundamentals of microwave photonics

    CERN Document Server

    Urick, V J; McKinney , Jason D

    2015-01-01

    A comprehensive resource to designing andconstructing analog photonic links capable of high RFperformanceFundamentals of Microwave Photonics provides acomprehensive description of analog optical links from basicprinciples to applications.  The book is organized into fourparts. The first begins with a historical perspective of microwavephotonics, listing the advantages of fiber optic links anddelineating analog vs. digital links. The second section coversbasic principles associated with microwave photonics in both the RFand optical domains.  The third focuses on analog modulationformats-starti

  16. Microwave Assisted Drug Delivery

    DEFF Research Database (Denmark)

    Jónasson, Sævar Þór; Zhurbenko, Vitaliy; Johansen, Tom Keinicke

    2014-01-01

    In this work, the microwave radiation is adopted for remote activation of pharmaceutical drug capsules inside the human body in order to release drugs at a pre-determined time and location. An array of controllable transmitting sources is used to produce a constructive interference at a certain...... focus point inside the body, where the drugs are then released from the specially designed capsules. An experimental setup for microwave activation has been developed and tested on a body phantom that emulates the human torso. A design of sensitive receiving structures for integration with a drug...

  17. Microwave Assisted Drug Delivery

    DEFF Research Database (Denmark)

    Jónasson, Sævar Þór; Zhurbenko, Vitaliy; Johansen, Tom Keinicke

    2014-01-01

    In this work, the microwave radiation is adopted for remote activation of pharmaceutical drug capsules inside the human body in order to release drugs at a pre-determined time and location. An array of controllable transmitting sources is used to produce a constructive interference at a certain...... focus point inside the body, where the drugs are then released from the specially designed capsules. An experimental setup for microwave activation has been developed and tested on a body phantom that emulates the human torso. A design of sensitive receiving structures for integration with a drug...

  18. EDITORIAL: Microwave Moisture Measurements

    Science.gov (United States)

    Kaatze, Udo; Kupfer, Klaus; Hübner, Christof

    2007-04-01

    Microwave moisture measurements refer to a methodology by which the water content of materials is non-invasively determined using electromagnetic fields of radio and microwave frequencies. Being the omnipresent liquid on our planet, water occurs as a component in most materials and often exercises a significant influence on their properties. Precise measurements of the water content are thus extremely useful in pure sciences, particularly in biochemistry and biophysics. They are likewise important in many agricultural, technical and industrial fields. Applications are broad and diverse, and include the quality assessment of foodstuffs, the determination of water content in paper, cardboard and textile production, the monitoring of moisture in sands, gravels, soils and constructions, as well as the measurement of water admixtures to coal and crude oil in reservoirs and in pipelines. Microwave moisture measurements and evaluations require insights in various disciplines, such as materials science, dielectrics, the physical chemistry of water, electrodynamics and microwave techniques. The cooperation of experts from the different fields of science is thus necessary for the efficient development of this complex discipline. In order to advance cooperation the Workshop on Electromagnetic Wave Interaction with Water and Moist Substances was held in 1993 in Atlanta. It initiated a series of international conferences, of which the last one was held in 2005 in Weimar. The meeting brought together 130 scientists and engineers from all over the world. This special issue presents a collection of some selected papers that were given at the event. The papers cover most topics of the conference, featuring dielectric properties of aqueous materials, electromagnetic wave interactions, measurement methods and sensors, and various applications. The special issue is dedicated to Dr Andrzej W Kraszewski, who died in July 2006 after a distinguished career of 48 years in the research of

  19. Understanding microwave vessel contamination by chloride species.

    Science.gov (United States)

    Recchia, Sandro; Spanu, Davide; Bianchi, Davide; Dossi, Carlo; Pozzi, Andrea; Monticelli, Damiano

    2016-10-01

    Microwaves are widely used to assist digestion, general sample treatment and synthesis. The use of aqua regia is extensively adopted for the closed vessel mineralization of samples prior to trace element detection, leading to the contamination of microwave vessels by chlorine containing species. The latter are entrapped in the polymeric matrix of the vessels, leading to memory effects that are difficult to remove, among which the risk of silver incomplete recoveries by removal of the sparingly soluble chloride is the predominant one. In the present paper, we determined by mass spectrometry that hydrogen chloride is the species entrapped in the polymeric matrix and responsible for vessel contamination. Moreover, several decontamination treatments were considered to assess their efficiency, demonstrating that several cleaning cycles with water, nitric acid or silver nitrate in nitric acid were inefficient in removing chloride contamination (contamination reduction around 90%). Better results (≈95% decrease) were achieved by a single decontamination step in alkaline environment (sodium hydroxide or ammonia). Finally, a thermal treatment in a common laboratory oven (i.e. without vacuum and ventilation) was tested: a one hour heating at 150°C leads to a 98.5% decontamination, a figure higher than the ones obtained by wet treatments which requires comparable time. The latter treatment is a major advancement with respect to existing treatments as it avoids the need of a vacuum oven for at least 17h as presently proposed in the literature.

  20. Systematic distortion in cosmic microwave background maps

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    To minimize instrumentally the induced systematic errors,cosmic microwave background(CMB)anisotropy experiments measure temperature differences across the sky using pairs of horn antennas, temperature map is recovered from temperature difference obtained in sky survey through a map-making procedure.To inspect and calibrate residual systematic errors in the recovered temperature maps is important as most previous studies of cosmology are based on these maps.By analyzing pixel-ring coupling and latitude dependence of CMB temperatures,we find notable systematic devia- tion from CMB Gaussianity in released Wilkinson Microwave Anisotropy Probe(WMAP)maps.The detected deviation cannot be explained by the best-fit LCDM cosmological model at a confidence level above 99%and cannot be ignored for a precision cosmology study.

  1. Modelling of two-stage anaerobic digestion using the IWA Anaerobic Digestion Model No. 1 (ADM1).

    Science.gov (United States)

    Blumensaat, F; Keller, J

    2005-01-01

    The aim of the study presented was to implement a process model to simulate the dynamic behaviour of a pilot-scale process for anaerobic two-stage digestion of sewage sludge. The model implemented was initiated to support experimental investigations of the anaerobic two-stage digestion process. The model concept implemented in the simulation software package MATLAB/Simulink is a derivative of the IWA Anaerobic Digestion Model No.1 (ADM1) that has been developed by the IWA task group for mathematical modelling of anaerobic processes. In the present study the original model concept has been adapted and applied to replicate a two-stage digestion process. Testing procedures, including balance checks and 'benchmarking' tests were carried out to verify the accuracy of the implementation. These combined measures ensured a faultless model implementation without numerical inconsistencies. Parameters for both, the thermophilic and the mesophilic process stage, have been estimated successfully using data from lab-scale experiments described in literature. Due to the high number of parameters in the structured model, it was necessary to develop a customised procedure that limited the range of parameters to be estimated. The accuracy of the optimised parameter sets has been assessed against experimental data from pilot-scale experiments. Under these conditions, the model predicted reasonably well the dynamic behaviour of a two-stage digestion process in pilot scale.

  2. Testing in Literature. ERIC Digest.

    Science.gov (United States)

    Purves, Alan C.

    Pointing out that student testing in literature should take into account each school's philosophy concerning the literature curriculum, this digest explores the broad domain of literature study and looks at specific objectives and outcomes in literature testing. The digest discusses answers to the following questions: (1) Where are the broad…

  3. Anaerobic digestion of solid material

    DEFF Research Database (Denmark)

    Vavilin, V.A.; Lokshina, L.Y.; Flotats, X.

    2007-01-01

    A new multidimensional (3 and 2D) anaerobic digestion model for cylindrical reactor with non-uniform influent concentration distributions was developed to study the way in which mixing intensity affects the efficiency of continuous-flow anaerobic digestion. Batch experiments reported and simulate...

  4. Foaming in manure based digesters

    DEFF Research Database (Denmark)

    Kougias, Panagiotis; Boe, Kanokwan; Angelidaki, Irini

    2012-01-01

    Anaerobic digestion foaming is one of the major problems that occasionally occurred in the Danish full-scale biogas plants, affecting negatively the overall digestion process. The foam is typically formatted in the main biogas reactor or in the pre-storage tank and the entrapped solids in the foam...... cause severe operational problems, such as blockage of mixing devices, and collapse of pumps. Furthermore, the foaming problem is linked with economic consequences for biogas plants, due to income losses derived from the reduced biogas production, extra labour work and additional maintenance costs....... Moreover, foaming presents adverse environmental impacts owing to the overflowing of the pre-storage or digester tanks. So far, there has never been thoroughly investigation of foaming problem in manure-based digester, which is the main anaerobic digestion applied in Denmark. The purpose of the present...

  5. Mercury speciation by high-performance liquid chromatography atomic fluorescence spectrometry using an integrated microwave/UV interface. Optimization of a single step procedure for the simultaneous photo-oxidation of mercury species and photo-generation of Hg{sup 0}

    Energy Technology Data Exchange (ETDEWEB)

    Quadros, Daiane P.C. de [Departamento de Química, Universidade Federal de Santa Catarina, 88040-970 Florianópolis, SC (Brazil); Campanella, Beatrice; Onor, Massimo; Bramanti, Emilia [National Research Council of Italy, C.N.R., Instituto di Chimica dei Composti Organo Metallici – ICCOM – UOS Pisa, Area della Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy); Borges, Daniel L.G. [Departamento de Química, Universidade Federal de Santa Catarina, 88040-970 Florianópolis, SC (Brazil); D' Ulivo, Alessandro, E-mail: dulivo@pi.iccom.cnr.it [National Research Council of Italy, C.N.R., Instituto di Chimica dei Composti Organo Metallici – ICCOM – UOS Pisa, Area della Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy)

    2014-11-01

    We described the hyphenation of photo-induced chemical vapor generation with high performance liquid chromatography–atomic fluorescence spectrometry (HPLC–AFS) for the quantification of inorganic mercury, methylmercury (MeHg) and ethylmercury (EtHg). In the developed procedure, formic acid in mobile phase was used for the photodecomposition of organomercury compounds and reduction of Hg{sup 2+} to mercury vapor under microwave/ultraviolet (MW/UV) irradiation. We optimized the proposed method studying the influence of several operating parameters, including the type of organic acid and its concentration, MW power, composition of HPLC mobile phase and catalytic action of TiO{sub 2} nanoparticles. Under the optimized conditions, the limits of detection were 0.15, 0.15 and 0.35 μg L{sup −1} for inorganic mercury, MeHg and EtHg, respectively. The developed method was validated by determination of the main analytical figures of merit and applied to the analysis of three certified reference materials. The online interfacing of liquid chromatography with photochemical-vapor generation–atomic fluorescence for mercury determination is simple, environmentally friendly, and represents an attractive alternative to the conventional tetrahydroborate (THB) system. - Highlights: • Inorganic and organic mercury were determined by photochemical vapor generation using a MW/UV photochemical reactor. • The optimized procedure has been applied to the speciation of Hg(II), MeHg and EtHg coupling HPLC with PVG–AFS. • The proposed method is simple, sensitive, and is established for mercury determination in biological materials.

  6. Microwave Radiation Hazards

    Directory of Open Access Journals (Sweden)

    G. Subrahmanian

    1973-07-01

    Full Text Available Excessive exposure to microwave radiation could lead to biological damage. The criteria for maximum permissible exposure limits derived from experiments by several countries are discussed. Recommendations made for safety of operating personnel based on a recent protection survey are also presented.

  7. Leakage of Microwave Ovens

    Science.gov (United States)

    Abdul-Razzaq, W.; Bushey, R.; Winn, G.

    2011-01-01

    Physics is essential for students who want to succeed in science and engineering. Excitement and interest in the content matter contribute to enhancing this success. We have developed a laboratory experiment that takes advantage of microwave ovens to demonstrate important physical concepts and increase interest in physics. This experiment…

  8. Leakage of Microwave Ovens

    Science.gov (United States)

    Abdul-Razzaq, W.; Bushey, R.; Winn, G.

    2011-01-01

    Physics is essential for students who want to succeed in science and engineering. Excitement and interest in the content matter contribute to enhancing this success. We have developed a laboratory experiment that takes advantage of microwave ovens to demonstrate important physical concepts and increase interest in physics. This experiment…

  9. Invisible to Microwaves

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Scientists can't yet make an invisibility cloak like the one that Harry Potter uses.But,for the first time,they've constructed a simple cloaking(1)d__that makes itself and something placed inside it invisible to microwaves.

  10. Assessing the agricultural reuse of the digestate from microalgae anaerobic digestion and co-digestion with sewage sludge.

    Science.gov (United States)

    Solé-Bundó, Maria; Cucina, Mirko; Folch, Montserrat; Tàpias, Josefina; Gigliotti, Giovanni; Garfí, Marianna; Ferrer, Ivet

    2017-05-15

    Microalgae anaerobic digestion produces biogas along with a digestate that may be reused in agriculture. However, the properties of this digestate for agricultural reuse have yet to be determined. The aim of this study was to characterise digestates from different microalgae anaerobic digestion processes (i.e. digestion of untreated microalgae, thermally pretreated microalgae and thermally pretreated microalgae in co-digestion with primary sludge). The main parameters evaluated were organic matter, macronutrients and heavy metals content, hygenisation, potential phytotoxicity and organic matter stabilisation. According to the results, all microalgae digestates presented suitable organic matter and macronutrients, especially organic and ammonium nitrogen, for agricultural soils amendment. However, the thermally pretreated microalgae digestate was the least stabilised digestate in comparison with untreated microalgae and co-digestion digestates. In vivo bioassays demonstrated that the digestates did not show residual phytotoxicity when properly diluted, being the co-digestion digestate the one which presented less phytotoxicity. Heavy metals contents resulted far below the threshold established by the European legislation on sludge spreading. Moreover, low presence of E. coli was observed in all digestates. Therefore, agricultural reuse of thermally pretreated microalgae and primary sludge co-digestate through irrigation emerges a suitable strategy to recycle nutrients from wastewater. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. A New Method for Determination of Arsenic and Mercury in Copper Concentrates: By High pressure airproof Microwave Digestion,Sequential Injection,Hydride Generation,and Atomic Fluorescence Spectrometry%一种检测铜精矿中砷和汞含量的新方法——高压密封微波消解-顺序注射-氢化物发生-原子荧光光谱法

    Institute of Scientific and Technical Information of China (English)

    苏明跃; 杨丽飞; 郭芬

    2011-01-01

    利用高压密封微波消解和顺序注射-氢化物发生-原子荧光光谱两项技术建立了检测铜精矿中砷、汞含量的新方法,并通过试验确定了适宜的检测条件.研究结果表明:本方法对砷的检出限为0.02μg/L,对汞的检出限为0.05μg/L;检测铜精矿中砷、汞的含量时,砷、汞的回收率分别为94.3%~107.0%和91.0%~102.0%,检测结果相对标准偏差分别在0.93%~1.97%之间和3.11%~8.07%之间,并且检测结果与认定值和国家标准方法测定值一致.%A new method for the determinations of arsenic content and mercury content in copper concentrates was founded by adopting two processes of high pressure-airproof microwave digestion and the sequential injection-hydride generation -atomic fluorescence spectrometry. Through tests, the optimum conditions for detection were determined. The tests resuits indicated that the detection limit of arsenic was 0.02 μg/L and the detection limit of mercury was 0.05 μg/L by this method. While detecting arsenic and mercury content in copper concentrate, it is found that the arsenic and mercury recovery rates reached 94.3% ~ 107.0% and 91.0% ~ 102.0% respectively with relative standard of deviation between 0.93% ~1.97% for arsenic and 3.11% ~ 8.07% for mercury. Also, these detecting results are in good agreement with the certified values and the values by the national standard method.

  12. Direct current plasma emission spectrometric determination of major, minor and trace elements in microwave oven acid leachates of powdered whole coal samples

    Energy Technology Data Exchange (ETDEWEB)

    Fadda, S. [CNR, Cagliari (Italy)

    2005-07-01

    Major concentrations of Al{sub 2}O{sub 3}, Fe{sub 2}O{sub 3}, MgO, CaO, Na{sub 2}O and K{sub 2}O, minor levels of TiO{sub 2}, P{sub 2}O{sub 5} and thirty petrologically, geochemically and environmentally significant trace elements have been determined in microwave oven acid leachates of whole powdered coal samples by direct current plasma-atomic emission spectrometry (DCP-AES). A single sample preparation procedure was suitable for all the determinations with no additional dilution step for major elements solution. Dried samples (0.5 g) were treated in low-pressure PFA digestion vessels with HF/HCl/HNO{sub 3}/HClO{sub 4} acids to quantitatively extract the analytes from the bulk material, while leaving the major part of organic matrix as a residue. To evaluate the accuracy of the microwave oven-DCP method a suite of eight certified coal reference materials of differing rank, were analysed with good agreement with the certified and/or available published data. Results are presented for the uncertified major oxides in the AR series reference materials.

  13. Microwave dissolution of plant tissue and the subsequent determination of trace lanthanide and actinide elements by inductively coupled plasma-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Alvarado, J.S.; Neal, T.J.; Smith, L.L.; Erickson, M.D.

    1997-08-01

    Recently there has been much concern with the ability of plants to uptake heavy metals from their surroundings. With the development of instrumental techniques with low detection limits such as inductively coupled plasma-mass spectrometry (ICP-MS), attention is shifting toward achieving faster and more elegant ways of oxidizing the organic material inherent in environmental samples. Closed-vessel microwave dissolution was compared with conventional methods for the determination of concentrations of cerium, samarium, europium, terbium, uranium and thorium in a series of samples from the National Institute of Standards and Technology and from fields in Idaho. The ICP-MS technique exhibited detection limits in parts-per-trillion and linear calibration plots over three orders of magnitude for the elements under study. The results obtained by using nitric acid and hydrogen peroxide in a microwave digestion system for the analysis of reference materials showed close agreement with the accepted values. These values were compared with results obtained from dry- and wet-ashing procedures. The findings from an experiment comparing radiometric techniques for the determination of actinide elements to ICP-MS are reported.

  14. An ultrasound-assisted digestion method for the determination of toxic element concentrations in ash samples by inductively coupled plasma optical emission spectrometry.

    Science.gov (United States)

    Ilander, Aki; Väisänen, Ari

    2007-10-29

    A method of ultrasound-assisted digestion followed by inductively coupled plasma optical emission spectrometry (ICP-OES) used for the determination of toxic element concentrations (arsenic, barium, cobalt, copper, lead, nickel, strontium, vanadium and zinc) in ash samples was developed. All the measurements were performed in robust plasma conditions which were tested by measuring the Mg(II) 280.270 nm/Mg(I) 285.213 nm line intensity ratios. The highest line intensity ratios were observed when a nebulizer gas flow of 0.6 L min(-1), auxiliary gas flow of 0.2 L min(-1) and plasma power of 1400 W were used for radially viewed plasma. The analysis of SRM 1633b showed that the ultrasound-assisted method developed is highly comparable with the microwave digestion method standardized by the United States Environmental Protection Agency (EPA-3052). The ultrasound-assisted digestion with a digestion solution of aqua regia and hydrofluoric acid (HF) resulted in recovery rates of over 81%. One exception is arsenic which resulted in recoveries of about 60% only; however, it could be digested with good recovery (>90%) using a digestion solution of 5 mL of water and 5 mL of aqua regia. The major advantage of the ultrasound-assisted digestion over microwave digestion is the high treatment rate (30 samples simultaneously with a sonication time of 18 min).

  15. Analysis of digester design concepts

    Energy Technology Data Exchange (ETDEWEB)

    Ashare, E.; Wilson, E. H.

    1979-01-29

    Engineering economic analyses were performed on various digester design concepts to determine the relative performance for various biomass feedstocks. A comprehensive literature survey describing the state-of-the-art of the various digestion designs is included. The digester designs included in the analyses are CSTR, plug flow, batch, CSTR in series, multi-stage digestion and biomethanation. Other process options investigated included pretreatment processes such as shredding, degritting, and chemical pretreatment, and post-digestion processes, such as dewatering and gas purification. The biomass sources considered include feedlot manure, rice straw, and bagasse. The results of the analysis indicate that the most economical (on a unit gas cost basis) digester design concept is the plug flow reactor. This conclusion results from this system providing a high gas production rate combined with a low capital hole-in-the-ground digester design concept. The costs determined in this analysis do not include any credits or penalties for feedstock or by-products, but present the costs only for conversion of biomass to methane. The batch land-fill type digester design was shown to have a unit gas cost comparable to that for a conventional stirred tank digester, with the potential of reducing the cost if a land-fill site were available for a lower cost per unit volume. The use of chemical pretreatment resulted in a higher unit gas cost, primarily due to the cost of pretreatment chemical. A sensitivity analysis indicated that the use of chemical pretreatment could improve the economics provided a process could be developed which utilized either less pretreatment chemical or a less costly chemical. The use of other process options resulted in higher unit gas costs. These options should only be used when necessary for proper process performance, or to result in production of a valuable by-product.

  16. Transurethral microwave thermotherapy for benign prostatic hyperplasia

    Directory of Open Access Journals (Sweden)

    Rubeinstein Jonathan N.

    2003-01-01

    Full Text Available Transurethral resection of the prostate (TURP remains the gold standard for treatment of benign prostatic hyperplasia (BPH. In general, while this procedure is safe, patients require a spinal, epidural, or general anesthesia and often several days of hospital stay; the potential morbidity and mortality limits the use of TURP in high-risk patients. Pharmacotherapy has been recommended as a first-line therapy for all patients with mild to moderate symptoms. Patients are oftentimes enthusiastic if they are offered a one-time method to treat lower urinary tract symptoms secondary to BPH, provided that the method offers reduced risk and allows an efficacy equal to that of medical therapy. One such method is transurethral microwave thermotherapy (TUMT. TUMT involves the insertion of a specially designed urinary catheter with a microwave antenna, which heats the prostate and destroys hyperplastic prostate tissue. TUMT allows the avoidance of general or regional anesthesia, and results in minimal blood loss and fluid absorption. In this review, the authors discussed the current indications and outcome of TUMT, including the history of the procedure, the mechanism of action, the indications for TUMT, the pre-operative considerations, the patient selection, the results in terms of efficacy, by comparing TUMT vs. Sham, TUMT vs. Alpha-blocker and TUMT vs. TURP. Finally, the complications are presented, as well as other uses and future directions of the procedure. The authors concluded that TUMT is a safe and effective minimally invasive alternative to treatment of symptomatic BPH.

  17. An enzyme complex increases in vitro dry matter digestibility of corn and wheat in pigs.

    Science.gov (United States)

    Park, Kyu Ree; Park, Chan Sol; Kim, Beob Gyun

    2016-01-01

    Two experiments were conducted to determine the effects of enzyme complex on in vitro dry matter (DM) digestibility for feed ingredients. The objective of experiment 1 was to screen feed ingredients that can be effective substrates for an enzyme complex, mainly consisted of β-pentosanase, β-glucanase and α-amylase, using in vitro digestibility methods. In experiment 1, the test ingredients were three grain sources (barley, corn and wheat) and six protein supplements (canola meal, copra expellers, cottonseed meal, distillers dried grains with solubles, palm kernel expellers and soybean meal). In vitro ileal and total tract digestibility (IVID and IVTTD, respectively) of DM for test ingredients were determined. In vitro digestibility methods consisted of two- or three-step procedure simulating in vivo digestion in the pig gastrointestinal tracts with or without enzyme complex. As the enzyme complex added, the IVID of DM for corn and wheat increased (p vitro digestibility of the fractions (starch, germ, hull and gluten) that maximally respond to the enzyme complex in experiment 2. The IVID of DM for corn starch, germ and hull increased (p vitro DM digestibility of corn and wheat, and the digestibility increments of corn are mainly attributed to the increased digestibility of corn starch.

  18. INEXPENSIVE, OFF THE SHELF HYBRID MICROWAVE SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Walters, T; Paul Burket, P; John Scogin, J

    2007-06-21

    A hybrid-heating microwave oven provides the energy to heat small 10-gram samples of spent metal tritide storage bed material to release tenaciously held decay product {sup 3}He. Complete mass balance procedures require direct measurement of added or produced gases on a tritide bed, and over 1100 C is necessary to release deep trapped {sup 3}He. The decomposition of non-radioactive CaCO{sub 3} and the quantitative measurement of CO{sub 2} within 3% of stoichiometry demonstrate the capabilities of the apparatus to capture generated (released) gases.

  19. Implementing Livestock Anaerobic Digestion Projects

    Science.gov (United States)

    Page provides information to help make an informed decision about installing an anaerobic digester. Is it a good match for a farm’s organic waste, project financing, development guidelines and permit requirements?

  20. Anaerobic digestion of pulp and paper mill wastewater and sludge.

    Science.gov (United States)

    Meyer, Torsten; Edwards, Elizabeth A

    2014-11-15

    sludge) and primary sludge is still in its infancy. Current research is mainly focused on developing efficient pretreatment methods that enable fast hydrolysis of complex organic matter, shorter sludge residence times and as a consequence, smaller sludge digesters. Previous experimental studies indicate that the anaerobic digestibility of non-pretreated biosludge from pulp and paper mills varies widely, with volatile solids (VS) removal rates of 21-55% and specific methane yields ranging between 40 and 200 mL g(-1) VS fed. Pretreatment can increase the digestibility to some extent, however in almost all reported cases, the specific methane yield of pretreated biosludge did not exceed 200 mL g(-1) VS fed. Increases in specific methane yield mostly range between 0 and 90% compared to non-pretreated biosludge, whereas larger improvements were usually achieved with more difficult-to-digest biosludge. Thermal treatment and microwave treatment are two of the more effective methods. The heat required for the elevated temperatures applied in both methods may be provided from surplus heat that is often available at pulp and paper mills. Given the large variability in specific methane yield of non-pretreated biosludge, future research should focus on the links between anaerobic digestibility and sludge properties. Research should also involve mill-derived primary sludge. Although biosludge has been the main target in previous studies, primary sludge often constitutes the bulk of mill-generated sludge, and co-digestion of a mixture between both types of sludge may become practical. The few laboratory studies that have included mill primary sludge indicate that, similar to biosludge, the digestibility can range widely. Long-term studies should be conducted to explore the potential of microbial adaptation to lignocellulosic material which can constitute more than half of the organic matter in pulp and paper mill sludge.

  1. The Cosmic Microwave Background

    Directory of Open Access Journals (Sweden)

    Jones Aled

    1998-01-01

    Full Text Available We present a brief review of current theory and observations of the cosmic microwave background (CMB. New predictions for cosmological defect theories and an overview of the inflationary theory are discussed. Recent results from various observations of the anisotropies of the microwave background are described and a summary of the proposed experiments is presented. A new analysis technique based on Bayesian statistics that can be used to reconstruct the underlying sky fluctuations is summarised. Current CMB data is used to set some preliminary constraints on the values of fundamental cosmological parameters $Omega$ and $H_circ$ using the maximum likelihood technique. In addition, secondary anisotropies due to the Sunyaev-Zel'dovich effect are described.

  2. Nuclear Regulatory Commission information digest

    Energy Technology Data Exchange (ETDEWEB)

    None,

    1990-03-01

    The Nuclear Regulatory Commission information digest provides summary information regarding the US Nuclear Regulatory Commission, its regulatory responsibilities, and areas licensed by the commission. This is an annual publication for the general use of the NRC Staff and is available to the public. The digest is divided into two parts: the first presents an overview of the US Nuclear Regulatory Commission and the second provides data on NRC commercial nuclear reactor licensees and commercial nuclear power reactors worldwide.

  3. Microwave Processing of Materials

    Science.gov (United States)

    1994-01-01

    Pennsylvania: Materials Research Society. Wagner, C., and W. Schottky. 1930. Zeitschrift fuer Physikalische Chemie. BL11:163. Walkiewicz, J. W., A. E. Clark...Science and Engineering. 66:468--469. Bloch, F. 1928. Zeitschrift fuer Physik. 52:555. Boch, P., N. Lequeux and P. Piluso. 1992. Reaction Sintering...Frankel, J. 1926. Zeitschrift fuer Physik. 35:652. Fukushima, H., T. Yamaka, and M. Matsui. 1990. Microwave Heating of Ceramics and its Application to

  4. SUNIST Microwave Power System

    Institute of Scientific and Technical Information of China (English)

    Feng Songlin; Yang Xuanzong; Feng Chunhua; Wang Long; Rao Jun; Feng Kecheng

    2005-01-01

    Experiments on the start-up and formation of spherical tokamak plasmas by electron cyclotron heating alone without ohmic heating and electrode discharge assisted electron cyclotron wave current start-up will be carried out on the SUNIST (Sino United Spherical Tokamak) device.The 2.45 GHz/100 kW/30 ms microwave power system and 1000 V/50 A power supply for electrode discharge are ready for experiments with non-inductive current drive.

  5. Microwave Multicomponent Synthesis

    Directory of Open Access Journals (Sweden)

    Helmut M. Hügel

    2009-12-01

    Full Text Available In the manner that very important research is often performed by multidisciplinary research teams, the applications of multicomponent reactions involving the combination of multiple starting materials with different functional groups leading to the higher efficiency and environmentally friendly construction of multifunctional/complex target molecules is growing in importance. This review will explore the advances and advantages in microwave multicomponent synthesis (MMS that have been achieved over the last five years.

  6. Application of Anaerobic Digestion Model No. 1 for simulating anaerobic mesophilic sludge digestion

    Energy Technology Data Exchange (ETDEWEB)

    Mendes, Carlos, E-mail: carllosmendez@gmail.com; Esquerre, Karla, E-mail: karlaesquerre@ufba.br; Matos Queiroz, Luciano, E-mail: lmqueiroz@ufba.br

    2015-01-15

    Highlights: • The behavior of a anaerobic reactor was evaluated through modeling. • Parametric sensitivity analysis was used to select most sensitive of the ADM1. • The results indicate that the ADM1 was able to predict the experimental results. • Organic load rate above of 35 kg/m{sup 3} day affects the performance of the process. - Abstract: Improving anaerobic digestion of sewage sludge by monitoring common indicators such as volatile fatty acids (VFAs), gas composition and pH is a suitable solution for better sludge management. Modeling is an important tool to assess and to predict process performance. The present study focuses on the application of the Anaerobic Digestion Model No. 1 (ADM1) to simulate the dynamic behavior of a reactor fed with sewage sludge under mesophilic conditions. Parametric sensitivity analysis is used to select the most sensitive ADM1 parameters for estimation using a numerical procedure while other parameters are applied without any modification to the original values presented in the ADM1 report. The results indicate that the ADM1 model after parameter estimation was able to predict the experimental results of effluent acetate, propionate, composites and biogas flows and pH with reasonable accuracy. The simulation of the effect of organic shock loading clearly showed that an organic shock loading rate above of 35 kg/m{sup 3} day affects the performance of the reactor. The results demonstrate that simulations can be helpful to support decisions on predicting the anaerobic digestion process of sewage sludge.

  7. Laboratory to pilot scale: Microwave extraction for polyphenols lettuce.

    Science.gov (United States)

    Périno, Sandrine; Pierson, Jean T; Ruiz, Karine; Cravotto, Giancarlo; Chemat, Farid

    2016-08-01

    Microwave hydrodiffusion and gravity (MHG) technique has been applied to pilot-scale solvent-free microwave extraction (SFME) of polyphenols from Lettuce sativa. Following the dictates of green extraction and with the aim to save time and energy, the lab-scale knowledge on SFME was exploited for the development of a pilot-scale process. The investigation entailed the optimization of all main parameters (temperature, time, extracted water volume, etc.) and we showed that the polyphenols composition profile under SFME was similar to the classic methods though a bit lower in total content. The energy consumption in the optimized procedure (30min) was 1W/g of fresh matrix.

  8. Starch digestion capacity of poultry.

    Science.gov (United States)

    Svihus, B

    2014-09-01

    Starch is quantitatively the most important nutrient in poultry diets and will to a large extent be present as intact starch granules due to very limited extent of gelatinization during pelleting. Although native starch is difficult to digest due to a semi-crystalline structure, even fast-growing broiler chickens appears to be able to digest this starch more or less completely during passage through the jejunum. However, reduced starch digestibility has been observed, particularly in pelleted diets containing large quantities of wheat. Although properties of the starch granule such as size and components on the granule surface may affect digestibility, the entrapment of starch granules in cell walls and a protein matrix may be even more important factors impeding starch digestion. In that case, this and the fact that amylase secretion is normally very high in poultry may explain the lack of convincing effects of exogenous α-amylase added to the diet. However, few well-designed experiments assessing mechanisms of starch digestion and the effect of α-amylase supplementation have been carried out, and thus more research is needed in this important area.

  9. Comprehensive utilization of digested residue

    Energy Technology Data Exchange (ETDEWEB)

    Reizhi Shen [Soil and Fertilizer Inst. of Shanghai Academy of Agricultural Sciences (China)

    2000-07-01

    The application history of biogas technology in China covers almost one century. Until the 1980's, people's attention not only focused on the benefit of biogas as people's daily fuel, but also on the comprehensive utilization of digested residues. People are more and more interested in these methods of comprehensive utilization, which has led to many research projects on, among others, ''digested effluent as feed additive for pigs'', ''digested sludge for growing mushroom'', and ''digested effluent as pesticide''. Not only are biogas fermentation, organic waste such as animal manure, crop straw, distillery wastewater and the wastewater from slaughter houses converted to biogas, but also digested residues are very useful with a lot of ''potential value'' and ''special functions'', which will bring far more benefits than biogas alone. Some progress on the comprehensive utilization of digested residues in the past ten years is summarized below. (orig.)

  10. Microwave sterilization method and apparatus

    OpenAIRE

    V. N. Vasilenko; Minuhin, V. V.; Podorozhnyak, A. A.; Trubaev, S. I.

    1995-01-01

    Experience of industrially developed countries in utilization of microwave radiation has been analyzed. Apparatus for realization of microwave method of sterilization has been designed. A number of experiments for the estimation of bactericidal, sporacidal, and virusidal properties of microwave radiation action has been carried out in 3 to 13 cm wavelength band. B. Lycheniform shtumm G., B. Subtilis ATTC 6633, E. Coli ATTC 25922 and bacterial virus FX 174 were used as test microbes. Effect of...

  11. Introduction to Microwave Linear [Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Whittum, David H

    1999-01-04

    The elements of microwave linear accelerators are introduced starting with the principles of acceleration and accelerating structures. Considerations for microwave structure modeling and design are developed from an elementary point of view. Basic elements of microwave electronics are described for application to the accelerator circuit and instrumentation. Concepts of beam physics are explored together with examples of common beamline instruments. Charged particle optics and lattice diagnostics are introduced. Considerations for fixed-target and colliding-beam experimentation are summarized.

  12. Microwave-Assisted Olefin Metathesis

    Science.gov (United States)

    Nicks, François; Borguet, Yannick; Sauvage, Xavier; Bicchielli, Dario; Delfosse, Sébastien; Delaude, Lionel; Demonceau, Albert

    Since the first reports on the use of microwave irradiation to accelerate organic chemical transformations, a plethora of papers have been published in this field. In most examples, microwave heating has been shown to dramatically reduce reaction times, increase product yields, and enhance product purity by reducing unwanted side reactions compared to conventional heating methods. The present contribution aims at illustrating the advantages of this technology in olefin metathesis and, when data are available, at comparing microwave-heated and conventionally heated experiments

  13. Determination of total iodine in serum and urine samples by ion chromatography with pulsed amperometric detection - studies on analyte loss, optimization of sample preparation procedures, and validation of analytical method.

    Science.gov (United States)

    Błażewicz, Anna; Klatka, Maria; Dolliver, Wojciech; Kocjan, Ryszard

    2014-07-01

    A fast, accurate and precise ion chromatography method with pulsed amperometric detection was applied to evaluate a variety of parameters affecting the determination of total iodine in serum and urine of 81 subjects, including 56 obese and 25 healthy Polish children. The sample pretreatment methods were carried out in a closed system and with the assistance of microwaves. Both alkaline and acidic digestion procedures were developed and optimized to find the simplest combination of reagents and the appropriate parameters for digestion that would allow for the fastest, least time consuming and most cost-effective way of analysis. A good correlation between the certified and the measured concentrations was achieved. The best recoveries (96.8% for urine and 98.8% for serum samples) were achieved using 1ml of 25% tetramethylammonium hydroxide solution within 6min for 0.1ml of serum/urine samples. Using 0.5ml of 65% nitric acid solution the best recovery (95.3%) was obtained when 7min of effective digestion time was used. Freeze-thaw stability and long-term stability were checked. After 24 weeks 14.7% loss of iodine in urine, and 10.9% in serum samples occurred. For urine samples, better correlation (R(2)=0.9891) of various sample preparation procedures (alkaline digestion and application of OnGuard RP cartidges) was obtained. Significantly lower iodide content was found in samples taken from obese children. Serum iodine content in obese children was markedly variable in comparison with the healthy group, whereas the difference was less evident when urine samples were analyzed. The mean content in serum was 59.12±8.86μg/L, and in urine 98.26±25.93 for obese children when samples were prepared by the use of optimized alkaline digestion reinforced by microwaves. In healthy children the mean content in serum was 82.58±6.01μg/L, and in urine 145.76±31.44μg/L.

  14. Numerical modeling of microwave heating

    Directory of Open Access Journals (Sweden)

    Shukla A.K.

    2010-01-01

    Full Text Available The present study compares the temperature distribution within cylindrical samples heated in microwave furnace with those achieved in radiatively-heated (conventional furnace. Using a two-dimensional finite difference approach the thermal profiles were simulated for cylinders of varying radii (0.65, 6.5, and 65 cm and physical properties. The influence of susceptor-assisted microwave heating was also modeled for the same. The simulation results reveal differences in the heating behavior of samples in microwaves. The efficacy of microwave heating depends on the sample size and its thermal conductivity.

  15. The Microwave SQUID Multiplexer

    Science.gov (United States)

    Mates, John Arthur Benson

    2011-12-01

    This thesis describes a multiplexer of Superconducting Quantum Interference Devices (SQUIDs) with low-noise, ultra-low power dissipation, and great scalability. The multiplexer circuit measures the magnetic flux in a large number of unshunted rf SQUIDs by coupling each SQUID to a superconducting microwave resonator tuned to a unique resonance frequency and driving the resonators from a common feedline. A superposition of microwave tones measures each SQUID simultaneously using only two coaxial cables between the cryogenic device and room temperature. This multiplexer will enable the instrumentation of arrays with hundreds of thousands of low-temperature detectors for new applications in cosmology, materials analysis, and nuclear non-proliferation. The driving application of the Microwave SQUID Multiplexer is the readout of large arrays of superconducting transition-edge sensors, by some figures of merit the most sensitive detectors of electromagnetic signals over a span of more than nine orders of magnitude in energy, from 40 GHz microwaves to 200 keV gamma rays. Modern transition-edge sensors have noise-equivalent power as low as 10-20 W / Hz1/2 and energy resolution as good as 2 eV at 6 keV. These per-pixel sensitivities approach theoretical limits set by the underlying signals, motivating a rapid increase in pixel count to access new science. Compelling applications, like the non-destructive assay of nuclear material for treaty verification or the search for primordial gravity waves from inflation use arrays of these detectors to increase collection area or tile a focal plane. We developed three generations of SQUID multiplexers, optimizing the first for flux noise 0.17 muPhi0 / Hz1/2, the second for input current noise 19 pA / Hz1/2, and the last for practical multiplexing of large arrays of cosmic microwave background polarimeters based on transition-edge sensors. Using the last design we demonstrated multiplexed readout of prototype polarimeters with the

  16. Non-Ionizing Radiation Used in Microwave Ovens

    Science.gov (United States)

    ... in Microwave Ovens Non-Ionizing Radiation Used in Microwave Ovens Explore the interactive, virtual community of RadTown USA ! ... learn more About Non-Ionizing Radiation Used in Microwave Ovens Microwave Oven. Microwave ovens use electromagnetic waves that ...

  17. Influence of digestion methods on the recovery of Iron, Zinc, Nickel, Chromium, Cadmium and Lead contents in 11 organic residues

    Directory of Open Access Journals (Sweden)

    Thalita Fernanda Abbruzzini

    2014-02-01

    Full Text Available There are currently many devices and techniques to quantify trace elements (TEs in various matrices, but their efficacy is dependent on the digestion methods (DMs employed in the opening of such matrices which, although "organic", present inorganic components which are difficult to solubilize. This study was carried out to evaluate the recovery of Fe, Zn, Cr, Ni, Cd and Pb contents in samples of composts and cattle, horse, chicken, quail, and swine manures, as well as in sewage sludges and peat. The DMs employed were acid digestion in microwaves with HNO3 (EPA 3051A; nitric-perchloric digestion with HNO3 + HClO4 in a digestion block (NP; dry ashing in a muffle furnace and solubilization of residual ash in nitric acid (MDA; digestion by using aqua regia solution (HCl:HNO3 in the digestion block (AR; and acid digestion with HCl and HNO3 + H2O2 (EPA 3050. The dry ashing method led to the greatest recovery of Cd in organic residues, but the EPA 3050 protocol can be an alternative method for the same purpose. The dry ashing should not be employed to determine the concentration of Cr, Fe, Ni, Pb and Zn in the residues. Higher Cr and Fe contents are recovered when NP and EPA 3050 are employed in the opening of organic matrices. For most of the residues analyzed, AR is the most effective method for recovering Ni. Microwave-assisted digestion methods (EPA3051 and 3050 led to the highest recovery of Pb. The choice of the DM that provides maximum recovery of Zn depends on the organic residue and trace element analyzed.

  18. Microwave Plasma System: PVA Tepla 300

    Data.gov (United States)

    Federal Laboratory Consortium — Description: CORAL Name: Microwave Asher A tool using microwave oxygen plasma to remove organics on the surfaces Specifications / Capabilities: Frequency: 2.45 GHz...

  19. Anaerobic digestion and co-digestion of slaughterhouse wastes

    Directory of Open Access Journals (Sweden)

    Sonia Castellucci

    2013-09-01

    Full Text Available The use of renewable energy is becoming increasingly necessary in order to address the global warming problem and, as a consequence, has become an high priority for many countries. Biomass is a clean and renewable energy source with growing potential to replace conventional fossil fuels. Among biomass, residual and waste ones represent a great resource for energy generation since they permit both to eliminate a possible waste and to produce energy. In the present work, the case of slaughterhouse wastes (SHWs has been investigated. Anaerobic digestion is nowadays considered as one of the most important and sustainable conversion technology exploiting organic matter and biodegradable wastes. Biogas results from this bio-chemical process and mainly consists of methane and carbon dioxide, leading to produce thermal energy and/or electricity. In this paper, the European Regulations on animal by-products (ABPs are described, and some previous study on anaerobic digestion and co-digestion of ABPs - more precisely SHWs - are considered and compared in order to fix a starting point for future tests on their co-digestion in a micro-scale pilot digester. This is to define optimal feed ratio values which ensure an increasing content of methane in the outgoing biogas.

  20. The European Microwave Week 2008 and its Microwave Conferences

    NARCIS (Netherlands)

    Hoogeboom, P.; Van Vliet, F.

    2009-01-01

    Under the auspices of the European Microwave Association (EuMA) the 11th annual European Microwave Week was organized in the Amsterdam RAI Congress Centre, The Netherlands, 27-31 October 2008. This major event consisted this year of five conferences, an exhibition, and various side events. The 38th

  1. An Ant Colony Optimization Algorithm for Microwave Corrugated Filters Design

    Directory of Open Access Journals (Sweden)

    Ivan A. Mantilla-Gaviria

    2013-01-01

    Full Text Available A practical and useful application of the Ant Colony Optimization (ACO method for microwave corrugated filter design is shown. The classical, general purpose ACO method is adapted to deal with the microwave filter design problem. The design strategy used in this paper is an iterative procedure based on the use of an optimization method along with an electromagnetic simulator. The designs of high-pass and band-pass microwave rectangular waveguide filters working in the C-band and X-band, respectively, for communication applications, are shown. The average convergence performance of the ACO method is characterized by means of Monte Carlo simulations and compared with that obtained with the well-known Genetic Algorithm (GA. The overall performance, for the simulations presented herein, of the ACO is found to be better than that of the GA.

  2. Research Relative to High Spatial Resolution Passive Microwave Sounding Systems

    Science.gov (United States)

    Staelin, D. H.; Rosenkranz, P. W.

    1984-01-01

    Methods to obtain high resolution passive microwave weather observations, and understanding of their probable impact on numerical weather prediction accuracy were investigated. The development of synthetic aperture concepts for geosynchronous passive microwave sounders were studied. The effects of clouds, precipitation, surface phenomena, and atmospheric thermal fine structure on a scale of several kilometers were examined. High resolution passive microwave sounders (e.g., AMSU) with an increased number of channels will produce initialization data for numerical weather prediction (NWP) models with both increased spatial resolution and coverage. The development of statistical models for error growth in high resolution primitive equation NWP models which permit the consequences of various observing system alternatives, including sensors and assimilation times and procedures is discussed. A high resolution three dimensional primitive equation NWP model to determine parameters in an error growth model similar to that formulated by Lorenz, but with more degrees of freedom is utilized.

  3. Development and optimization of a standard method for extraction of microplastics in mussels by enzyme digestion of soft tissues.

    Science.gov (United States)

    Catarino, Ana I; Thompson, Richard; Sanderson, William; Henry, Theodore B

    2017-04-01

    The authors compared procedures for digestion of mussel soft tissues and extraction of microplastics. Complete tissue digestion was achieved with 1M NaOH, 35% HNO3 , and protease at 9.6 UHb/mL (unit hemoglobin per mL); but use of HNO3 caused unacceptable destruction of some microplastics. Recovery of microplastics spiked into mussels was similar (93 ± 10%) for NaOH and enzyme digestions. The authors recommend use of industrial enzymes based on digestion efficiency, microplastic recovery, and avoidance of caustic chemicals. Environ Toxicol Chem 2017;36:947-951. © 2016 SETAC.

  4. Non-decoloured In-gel Digestion of Coomassie Blue-stained Proteins

    Institute of Scientific and Technical Information of China (English)

    ZHANG Guo-an; BAO Hui-min; FAN Hui-zhi; YANG Peng-yuan

    2003-01-01

    A simplified method is presented for tryptic digestion of Coomassie brilliant blue(CBB)-stained proteins in polyacrylamide gels. Compared with conventional methods, the proposed method does not require a removal of the dye before digestion, and is thus faster and saves a lot of labor. The resulted digest can be analyzed by either RPLC/ESIMS or MALDI MS for identification of the protein in a conventional way. Model studies with bovine serum albumin(BSA) showed that 50 ng of the protein could be routinely identified. The simplified procedure displays a tendency to produce more incompletely cleaved peptides, which is favorable for improving the sequence coverage.

  5. Molecular hydrogelators of peptoid-peptide conjugates with superior stability against enzyme digestion

    Science.gov (United States)

    Wu, Zhidan; Tan, Ming; Chen, Xuemei; Yang, Zhimou; Wang, Ling

    2012-05-01

    We report on molecular hydrogelators based on peptoid-peptide conjugates with good biocompatibility to different cells and superior stability against proteinase K digestion.We report on molecular hydrogelators based on peptoid-peptide conjugates with good biocompatibility to different cells and superior stability against proteinase K digestion. Electronic supplementary information (ESI) available: Synthesis and characterization of gelators, dynamic strain sweep, cell viability, and procedure to determine the stability of compounds against proteinase K digestion. See DOI: 10.1039/c2nr30408b

  6. [Current state of digestive system robotic surgery in the light of evidence based medicine].

    Science.gov (United States)

    Ortiz Oshiro, Elena; Fernández-Represa, Jesús Alvarez

    2009-03-01

    The incorporation of robotics in minimally invasive surgery has had mixed reception in the different fields of digestive surgery. Nowadays we are exposed to a continuous stream of publications on robotic approach techniques and outcomes, which do not always provide objective criteria and whose value, through scientific evidence analysis, is sometimes arguable. With the aim of shedding light on current knowledge on digestive robotic surgery and giving an update of its possibilities, the authors analyse the abundant literature available on the different digestive robotic surgery procedures, and sum up their own experience.

  7. Microwave Sterilization in School Microbiology.

    Science.gov (United States)

    Wynn, Brian; Dixon, Angela

    1988-01-01

    Described are two investigations carried out in a high school biology department using a domestic microwave oven to compare the relative attributes of the autoclave and microwave oven in school use. Discussed are equipment, methods, and results of each investigation. (Author/CW)

  8. PROGRAMMING THE MICROWAVE-OVEN

    NARCIS (Netherlands)

    KOK, LP; VISSER, PE; BOON, ME

    1994-01-01

    Microwaves can be used to stimulate chemical bonding, diffusion of reagents into and out of the specimen, and coagulation processes in preparatory techniques. Temperature plays an important role in these processes. There are several ways of controlling the temperature of microwave-exposed tissue, fl

  9. More Experiments with Microwave Ovens

    Science.gov (United States)

    Vollmer, Michael; Mollmann, Klaus-Peter; Karstadt, Detlef

    2004-01-01

    Microwave ovens can be used to perform exciting demonstrations that illustrate a variety of physics topics. Experiments discussed here show superheating, visualize the inhomogeneous heating that takes place in a microwave and also show how to use a mobile phone to detect radiation leaking from the oven. Finally eggs can give some spectacular…

  10. More Experiments with Microwave Ovens

    Science.gov (United States)

    Vollmer, Michael; Mollmann, Klaus-Peter; Karstadt, Detlef

    2004-01-01

    Microwave ovens can be used to perform exciting demonstrations that illustrate a variety of physics topics. Experiments discussed here show superheating, visualize the inhomogeneous heating that takes place in a microwave and also show how to use a mobile phone to detect radiation leaking from the oven. Finally eggs can give some spectacular…

  11. PROGRAMMING THE MICROWAVE-OVEN

    NARCIS (Netherlands)

    KOK, LP; VISSER, PE; BOON, ME

    1994-01-01

    Microwaves can be used to stimulate chemical bonding, diffusion of reagents into and out of the specimen, and coagulation processes in preparatory techniques. Temperature plays an important role in these processes. There are several ways of controlling the temperature of microwave-exposed tissue,

  12. Digestão fotoquímica, assistida por microondas, de águas naturais: aplicação em estudos de partição e especiação do cobre

    Directory of Open Access Journals (Sweden)

    Sodré Fernando F.

    2004-01-01

    Full Text Available The efficiency of a new procedure for the digestion of natural waters, based on a microwave-activated photochemical reactor was evaluated in this work. Fluorescence spectra showed a 99% reduction in the emission of a 40 mg L-1 humic acid solution after 15 min of UV irradiation. In the presence of H2O2, only 3 min were necessary to accomplish a reduction of almost 100% in the emission and 6 min to reduce the concentration of dissolved organic carbon by 95%. The copper recovery from synthetic samples containing commercial humic acid, from soil suspensions, as well as from natural waters varied between 91.5 and 106.6%. The digestion of dissolved and unfiltered samples was successfully accomplished in 6 and 12 min, respectively. No contaminations or sample losses were observed. Results of copper speciation in natural waters showed that this metal is predominantly bound to natural ligands. Only 3-6% of the total recoverable copper is present in the labile form.

  13. The Distribution of Macro- and Micronutrients in Maize Within Separated Digestate Fertilizing (Digestate Fibre and Digestate Luquor: Field Trial

    Directory of Open Access Journals (Sweden)

    Kodymová Jana

    2016-12-01

    Full Text Available Along with the current increase in the number of biogas plants, huge amounts of digestate, i.e. waste products, are being generated. The common practice in the Czech Republic is to plough the digestate into the land. In our field trial, we compared the fertilizing effects of standard fertilizers applied in the Czech Republic with digestate as the only fertilizer (e.g. digestate fibre and digestate liquor in real agricultural conditions to find out whether a comparable amount of nitrogen is used in accordance with European legislation. The impact of separated digestate fibre and separated liquor on the soil fertility and quality was observed on the basis of the distribution of macro- and micronutrients in maize. The evaluation of growth increments in maize suggests that the fertilizing effects of digestate liquor or digestate fibre do not match the standard fertilizer in agriculture, but especially digestate liquor is comparable with other mineral fertilizers. Our field trial also shows that digestate liquor is a better fertilizer than digestate fibre, which may be explained by more appropriate ratios of available nutrients in digestate liquor. Digestate fibre may be recommended mainly for the aeration of clayey soil, but is not sustainable as fertilizer.

  14. Microwave Imaging of Human Forearms: Pilot Study and Image Enhancement

    Directory of Open Access Journals (Sweden)

    Colin Gilmore

    2013-01-01

    Full Text Available We present a pilot study using a microwave tomography system in which we image the forearms of 5 adult male and female volunteers between the ages of 30 and 48. Microwave scattering data were collected at 0.8 to 1.2 GHz with 24 transmitting and receiving antennas located in a matching fluid of deionized water and table salt. Inversion of the microwave data was performed with a balanced version of the multiplicative-regularized contrast source inversion algorithm formulated using the finite-element method (FEM-CSI. T1-weighted MRI images of each volunteer’s forearm were also collected in the same plane as the microwave scattering experiment. Initial “blind” imaging results from the utilized inversion algorithm show that the image quality is dependent on the thickness of the arm’s peripheral adipose tissue layer; thicker layers of adipose tissue lead to poorer overall image quality. Due to the exible nature of the FEM-CSI algorithm used, prior information can be readily incorporated into the microwave imaging inversion process. We show that by introducing prior information into the FEM-CSI algorithm the internal anatomical features of all the arms are resolved, significantly improving the images. The prior information was estimated manually from the blind inversions using an ad hoc procedure.

  15. Passive Microwave Components and Antennas

    DEFF Research Database (Denmark)

    State-of-the-art microwave systems always require higher performance and lower cost microwave components. Constantly growing demands and performance requirements of industrial and scientific applications often make employing traditionally designed components impractical. For that reason, the design...... and development process remains a great challenge today. This problem motivated intensive research efforts in microwave design and technology, which is responsible for a great number of recently appeared alternative approaches to analysis and design of microwave components and antennas. This book highlights...... techniques. Modelling and computations in electromagnetics is a quite fast-growing research area. The recent interest in this field is caused by the increased demand for designing complex microwave components, modeling electromagnetic materials, and rapid increase in computational power for calculation...

  16. Passive Microwave Components and Antennas

    DEFF Research Database (Denmark)

    techniques. Modelling and computations in electromagnetics is a quite fast-growing research area. The recent interest in this field is caused by the increased demand for designing complex microwave components, modeling electromagnetic materials, and rapid increase in computational power for calculation......State-of-the-art microwave systems always require higher performance and lower cost microwave components. Constantly growing demands and performance requirements of industrial and scientific applications often make employing traditionally designed components impractical. For that reason, the design...... and development process remains a great challenge today. This problem motivated intensive research efforts in microwave design and technology, which is responsible for a great number of recently appeared alternative approaches to analysis and design of microwave components and antennas. This book highlights...

  17. Microwave plasma combustion of coal

    Energy Technology Data Exchange (ETDEWEB)

    P.M. Kanilo; V.I. Kazantsev; N.I. Rasyuk; K. Schuenemann; D.M. Vavriv [Institute of Machine Building Problems of the National Academy of Sciences of Ukraine, Kharkov (Ukraine)

    2003-01-01

    Microwave plasma is studied as an alternative to oil or gas fuel for ignition and stabilisation of burning of lean coal. The study is performed on an experimental set-up, which includes a burner with a microwave plasma generator, coal and air supply systems, and measurement equipment. Power and thermochemical characteristics of the coal-plasma interaction have been measured and analysed. The obtained results indicate an essential intensification of ignition and combustion processes in the microwave burner compared to those in conventional burners. In particular, it has been demonstrated that the microwave energy consumption is only about 10% of the required expenditure of oil or gas, measured in heat equivalent. A design of an industrial microwave-plasma burner is proposed. Prospects of such burner for applications at industrial boilers of power plants are discussed. 6 refs., 4 figs., 2 tabs.

  18. 微波消解-耐氢氟酸系统进样电感耦合等离子体发射光谱法测定锰矿中铝磷镁铁锌镍%Determination of aluminum, phosphorus, magnesium, iron, zinc and nickel in manganese ore by inductively coupled plasma atomic emission spectrometry with hydrofluoric add resistant sampling system after microwave digestion

    Institute of Scientific and Technical Information of China (English)

    邓全道; 许光; 林冠春; 刘建发; 刘灵芝

    2011-01-01

    采用混合酸作溶剂微波消解试样,样液定客后,直接用耐氢氟酸进样系统(Duo HF KIT)进样,电感耦合等离子体发射光谱法(ICP-AES)测定锰矿石试液中的铝、磷、镁、铁、锌、镍,避免因为引入硼酸掩蔽氟离子而带来的基体干扰,缩短了检测时间.测定时选择波长为369.152 nm{85}、186.942 nm{481}、280.270 nm{120}、240.488 nm{140}、213.856 nm{457}和341.476 nm{99}光谱线分别作为Al、P、Mg、Fe、Zn、Ni分析线,采用基体匹配方法来消除锰的基体效应.本法已测定国家锰矿标准物质中铝、磷、镁、铁、锌、镍,并与国标方法测定结果相比对,分析结果与认定值及国标方法的测定值相符,且重复性好.各元素的加标回收率为94%~107%,测定结果的相对标准偏差(RSD,n=12)小于1.1%.%The samples were dissolved by microwave digestion using mixed acid as solvent. After dilution, the aluminum, phosphorus, magnesium, iron, zinc and nickel in manganese ore were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) using hydrofluoric acid resistant sampling system (Duo HF KIT). The matrix effect of boric acid introduced for masking fluorine ion was prevented , and the detection time was shortened. The spectral lines for Al, P, Mg, Fe, Zn and Ni were 369. 152 nm{ 85 } , 186. 942 nm{ 481 } , 280. 270 nm{120} , 240. 488 nm {140} , 213. 856 nm {457} and 341. 476 nm {99}, respectively. The matrix effect of manganese was eliminated by matrix matching method. The proposed method had been applied to the determination of aluminum, phosphorus, magnesium, iron, zinc and nickel in certified reference materials of manganese ore. The determination results were compared with those obtained by national standard method. It was found that the analytical results were consistent with the certified values and those obtained by national standard method. Moreover, the repeatability was good. The recoveries of elements were 94%-107

  19. Response surface optimization of microwave-assisted extraction for HPLC-fluorescence determination of puerarin and daidz

    Institute of Scientific and Technical Information of China (English)

    Ying-Kun Liu; E Yan; Han-Ying Zhan; Zhi-Qi Zhang

    2011-01-01

    Microwave-assisted extraction was optimized with response surface methodology for HPLC-fluorescence determination of puerarin and daidzein in Radix Puerariae thomsonii.The optimized extraction procedure was achieved by soaking the sample with 70% methanol

  20. Iodine Catalyzed Microwave-Assisted Synthesis of 14-Aryl(Alkyl)-14H-dibenzo[a,j]xanthenes

    Institute of Scientific and Technical Information of China (English)

    DING,Fei-Qing; AN,Li-Tao; ZOU,Jian-Ping

    2007-01-01

    A straightforward and effective procedure for the synthesis of 14-aryl(alkyl)-14H-dibenzo[a,j]xanthenes was described using a catalytic amount of molecular iodine under microwave irradiation to afford the corresponding xanthenes in good yields.

  1. Determination of multi-walled carbon nanotube bioaccumulation in earthworms measured by a microwave-based detection technique

    Science.gov (United States)

    Reliable quantification techniques for carbon nanotubes (CNTs) are limited. In this study, a new procedure was developed for quantifying multi-walled carbon nanotubes (MWNTs) in earthworms (Eisenia fetida) based on freeze drying and microwave-induced heating. Specifically, earthw...

  2. Determination of multi-walled carbon nanotube bioaccumulation in earthworms measured by a microwave-based detection technique

    Science.gov (United States)

    Reliable quantification techniques for carbon nanotubes (CNTs) are limited. In this study, a new procedure was developed for quantifying multi-walled carbon nanotubes (MWNTs) in earthworms (Eisenia fetida) based on freeze drying and microwave-induced heating. Specifically, earthw...

  3. A convenient catalyst system for microwave accelerated cross-coupling of a range of aryl boronic acids with aryl chlorides

    Directory of Open Access Journals (Sweden)

    Milton Edward J

    2007-05-01

    Full Text Available Abstract A convenient microwave accelerated cross-coupling procedure between aryl chlorides with a range of boronic acids has been developed. An explanation for the low reactivity of highly fluorinated boronic acids in Suzuki coupling is provided.

  4. Quality indicators in digestive endoscopy: introduction to structure, process, and outcome common indicators.

    Science.gov (United States)

    López-Picazo, Julio; Alberca de Las Parras, Fernando; Sánchez Del Río, Antonio; Pérez Romero, Shirley; León Molina, Joaquín; Júdez, Francisco Javier

    2017-06-01

    The general goal of the project wherein this paper is framed is the proposal of useful quality and safety procedures and indicators to facilitate quality improvement in digestive endoscopy units. This initial offspring sets forth procedures and indicators common to all digestive endoscopy procedures. First, a diagram of pre- and post-digestive endoscopy steps was developed. A group of health care quality and/or endoscopy experts under the auspices of the Sociedad Española de Patología Digestiva (Spanish Society of Digestive Diseases) carried out a qualitative review of the literature regarding the search for quality indicators in endoscopic procedures. Then, a paired analysis was used for the selection of literature references and their subsequent review. Twenty indicators were identified, including seven for structure, eleven for process (five pre-procedure, three intra-procedure, three post-procedure), and two for outcome. Quality of evidence was analyzed for each indicator using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) classification.

  5. Biochemical methane potential tests of different autoclaved and microwaved lignocellulosic organic fractions of municipal solid waste.

    Science.gov (United States)

    Pecorini, Isabella; Baldi, Francesco; Carnevale, Ennio Antonio; Corti, Andrea

    2016-10-01

    The aim of this research was to enhance the anaerobic biodegradability and methane production of two synthetic Organic Fractions of Municipal Solid Waste with different lignocellulosic contents by assessing microwave and autoclave pre-treatments. Biochemical Methane Potential assays were performed for 21days. Changes in the soluble fractions of the organic matter (measured by soluble chemical oxygen demand, carbohydrates and proteins), the first order hydrolysis constant kh and the cumulated methane production at 21days were used to evaluate the efficiency of microwaving and autoclaving pretreatments on substrates solubilization and anaerobic digestion. Microwave treatment led to a methane production increase of 8.5% for both the tested organic fractions while autoclave treatment had an increase ranging from 1.0% to 4.4%. Results showed an increase of the soluble fraction after pre-treatments for both the synthetic organic fractions. Soluble chemical oxygen demand observed significant increases for pretreated substrates (up to 219.8%). In this regard, the mediocre results of methane's production led to the conclusion that autoclaving and microwaving resulted in the hydrolysis of a significant fraction of non-biodegradable organic substances recalcitrant to anaerobic digestion.

  6. Digestible lysine requirements of broilers

    Directory of Open Access Journals (Sweden)

    LEP Bernal

    2014-03-01

    Full Text Available Modern broilers have been submitted to continuous genetic improvement, and therefore, their nutritional requirements must be constantly updated to ensure their performance. Two experiments were carried out to evaluate different digestible lysine levels for starter (1021 days and grower (22-35 days phases. The experiments were carried out with male and female Cobb 500 broilers, distributed according to a randomized block experimental design in a 5x2 factorial arrangement (5 increasing digestible lysine levels x 2 sexes, totaling 10 treatments, with 8 replicates of 22 and 20 birds during the starter and grower phase, respectively. Digestible lysine levels of 1.06, 1.12, 1.18, 1.24, and 1.30 were used in the starter diets (10-21 days and 0.9, 0.98, 1.04, 1.10, and 1.16% in the grower diets (22-35 days. Based on the statistical analyses of the evaluated performance parameters, digestible lysine requirements for maximum performance were determined as 1.22% for males and 1.24% for females in the starter phase, and 1.16% for both sexes in the grower phase. Carcass and performance results indicate that digestible lysine requirements vary with sex and evaluated production parameter. Considering the most relevant broiler production parameters, in 22- to 35-d-old males, digestible lysine requirement for breast meat yield (1.16% was higher than those for feed conversion ratio (1.07% and weight gain (1.05%.

  7. Determination of silica coating efficiency on metal particles using multiple digestion methods.

    Science.gov (United States)

    Wang, Jun; Topham, Nathan; Wu, Chang-Yu

    2011-10-15

    Nano-sized metal particles, including both elemental and oxidized metals, have received significant interest due to their biotoxicity and presence in a wide range of industrial systems. A novel silica technology has been recently explored to minimize the biotoxicity of metal particles by encapsulating them with an amorphous silica shell. In this study, a method to determine silica coating efficiency on metal particles was developed. Metal particles with silica coating were generated using gas metal arc welding (GMAW) process with a silica precursor tetramethylsilane (TMS) added to the shielding gas. Microwave digestion and Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) were employed to solubilize the metal content in the particles and analyze the concentration, respectively. Three acid mixtures were tested to acquire the appropriate digestion method targeting at metals and silica coating. Metal recovery efficiencies of different digestion methods were compared through analysis of spiked samples. HNO(3)/HF mixture was found to be a more aggressive digestion method for metal particles with silica coating. Aqua regia was able to effectively dissolve metal particles not trapped in the silica shell. Silica coating efficiencies were thus calculated based on the measured concentrations following digestion by HNO(3)/HF mixture and aqua regia. The results showed 14-39% of welding fume particles were encapsulated in silica coating under various conditions. This newly developed method could also be used to examine the silica coverage on particles of silica shell/metal core structure in other nanotechnology areas.

  8. Eff ect of microwave fi eld on trypsin inhibitors activity and protein quality of broad bean seeds (Vicia faba var. major

    Directory of Open Access Journals (Sweden)

    Mirosław Pysz

    2012-06-01

    Full Text Available Background. In human nutrition legume seeds are usually subjected to soaking and thermal processes, mainly by using traditional cooking method. This method which has been used for decades, does not allow to control and adjust the parameters of this process. Therefore it does not seem to be the optimal method. Undoubtedly, microwave fi eld is an alternative thermal process to conventional technique. The aim of this study was to assess the impact of microwave fi eld on the activity of trypsin inhibitors and protein quality of three varieties of broad bean seeds. Material and methods. The study was performed on dry seeds of broad bean varieties Windsor White, Bachus and Basta. The seeds were soaked and heated in a microwave. The seeds absorbed different energy doses from 500 J/g, through 750, 1000, 1250, 1500, 1750 to 2000 J/g. The study material prepared in this way was tested for trypsin inhibitor activity, protein solubility and in vitro protein digestibility. The results were analysed by the one-way analysis of variance. Results. Microwave heating resulted in decreased activity of trypsin inhibitors and protein solubility and increased digestibility of protein in all tested varieties of broad bean seeds. With increasing doses of the microwave fi eld energy a decrease in protein solubility was observed. Satisfactory reduction in trypsin inhibitors at the level of 70-75% and highest protein digestibility were obtained by using a microwave fi eld with energy dose of 1000 J/g of seeds. Conclusion. It can be concluded that the optimal dose of microwave energy fi eld which will produce a relatively low activity of trypsin inhibitors and the highest protein digestibility together with maintaining solubility of broad been seeds was 1000 J/g seed.

  9. Microwave systems design

    CERN Document Server

    Awang, Zaiki

    2014-01-01

    The aim of this book is to serve as a design reference for students and as an up-to-date reference for researchers. It also acts as an excellent introduction for newcomers to the field and offers established rf/microwave engineers a comprehensive refresher.  The content is roughly classified into two – the first two chapters provide the necessary fundamentals, while the last three chapters focus on design and applications. Chapter 2 covers detailed treatment of transmission lines. The Smith chart is utilized in this chapter as an important tool in the synthesis of matching networks for microwave amplifiers. Chapter 3 contains an exhaustive review of microstrip circuits, culled from various references. Chapter 4 offers practical design information on solid state amplifiers, while Chapter 5 contains topics on the design of modern planar filters, some of which were seldom published previously. A set of problems at the end of each chapter provides the readers with exercises which were compiled from actual uni...

  10. Microwave Frequency Multiplier

    Science.gov (United States)

    Velazco, J. E.

    2017-02-01

    High-power microwave radiation is used in the Deep Space Network (DSN) and Goldstone Solar System Radar (GSSR) for uplink communications with spacecraft and for monitoring asteroids and space debris, respectively. Intense X-band (7.1 to 8.6 GHz) microwave signals are produced for these applications via klystron and traveling-wave microwave vacuum tubes. In order to achieve higher data rate communications with spacecraft, the DSN is planning to gradually furnish several of its deep space stations with uplink systems that employ Ka-band (34-GHz) radiation. Also, the next generation of planetary radar, such as Ka-Band Objects Observation and Monitoring (KaBOOM), is considering frequencies in the Ka-band range (34 to 36 GHz) in order to achieve higher target resolution. Current commercial Ka-band sources are limited to power levels that range from hundreds of watts up to a kilowatt and, at the high-power end, tend to suffer from poor reliability. In either case, there is a clear need for stable Ka-band sources that can produce kilowatts of power with high reliability. In this article, we present a new concept for high-power, high-frequency generation (including Ka-band) that we refer to as the microwave frequency multiplier (MFM). The MFM is a two-cavity vacuum tube concept where low-frequency (2 to 8 GHz) power is fed into the input cavity to modulate and accelerate an electron beam. In the second cavity, the modulated electron beam excites and amplifies high-power microwaves at a frequency that is a multiple integer of the input cavity's frequency. Frequency multiplication factors in the 4 to 10 range are being considered for the current application, although higher multiplication factors are feasible. This novel beam-wave interaction allows the MFM to produce high-power, high-frequency radiation with high efficiency. A key feature of the MFM is that it uses significantly larger cavities than its klystron counterparts, thus greatly reducing power density and arcing

  11. Microwave drying for safe storage and improved nutritional quality of green gram seed (Vigna radiata).

    Science.gov (United States)

    Pande, Ranjana; Mishra, H N; Singh, M N

    2012-04-11

    The present study describes the effect of the microwave-heating method on disinfestations and physico characteristics, viz., grain size, grain hardness, and nutritional quality, of the stored green gram seed. It has been observed that the use of the microwave-heating method not only prolongs the storage duration of the green gram seed but also enhances its nutritional quality. The effect of independent parameters, viz., microwave power level and time of exposure, on the moisture content, insect mortality, color, and antinutrient factor (phyic acid) was optimized using response surface methodology (RSM), with the optimized value for power of 808 W and time at 80 s. The optimally treated green gram seed has 8.9% moisture, 99.5% insect mortality, 2.22 Δa* (green color of seed), and 591.79 mg/100 g of antinutrient factor (phytic acid). The grain size (geometric mean diameter, D(m)) of the control (untreated) sample was 3.75 mm, and that of the microwave-treated sample using optimum conditions was 3.99 mm. The grain hardness of the control sample was 3.31 kg, and that of the microwave-treated sample using optimum conditions was 1.305 kg. In vitro protein digestibility (IVPD) of the control (untreated) sample was 83 ± 0.289%, and that of the microwave-treated sample using optimum conditions was 85 ± 0.296%. These values are significantly difference (p microwave treatment resulted in a non-significant (p microwave heating not only increases the insect mortality but also reduces the moisture content and antinutritional factor (phytic acid), while the natural green color of the seed is not affected much. This study provides a novel and environmentally safe technique and increase in the nutritive quality.

  12. Traveling-Wave Tube Cold-Test Circuit Optimization Using CST MICROWAVE STUDIO

    Science.gov (United States)

    Chevalier, Christine T.; Kory, Carol L.; Wilson, Jeffrey D.; Wintucky, Edwin G.; Dayton, James A., Jr.

    2003-01-01

    The internal optimizer of CST MICROWAVE STUDIO (MWS) was used along with an application-specific Visual Basic for Applications (VBA) script to develop a method to optimize traveling-wave tube (TWT) cold-test circuit performance. The optimization procedure allows simultaneous optimization of circuit specifications including on-axis interaction impedance, bandwidth or geometric limitations. The application of Microwave Studio to TWT cold-test circuit optimization is described.

  13. A Facile Microwave-Assisted Synthesis of Some Fused Pyrimidine Derivatives

    Directory of Open Access Journals (Sweden)

    S. A. Al-Issa

    2014-06-01

    Full Text Available The highly accelerated synthesis of thienopyrimidinones, theino- pyrimidines,thioxotheinopyrimidinones and a thienotriazolopyrimidinone derivatives under microwave irradiation is reported. Compared to conventional conditions, microwaves method offered several advantage likes short time, good yields, simple procedure, mild conditions and easy workup. The structure of synthesized compounds have been characterized on the basis of their elemental analysis and spectral data, and screened for their antimicrobial activity.

  14. Mechanical properties and microstructural evolution of alumina-zirconia nanocomposites by microwave sintering

    OpenAIRE

    Benavente Martínez, Rut; Salvador Moya, Mª Dolores; Penaranda-Foix, Felipe L.; Pallone, Eliria; Borrell Tomás, María Amparo

    2014-01-01

    Microwave sintering has emerged in recent years as a novel method for sintering a variety of materials that have shown significant advantages against conventional sintering procedures. This work involved an investigation of microwave hybrid fast firing of alumina–zirconia nanocomposites using commercial alumina powder and monoclinic nanometric zirconia. The suspensions were prepared separately in order to obtain 5, 10 and 15 vol% of ZrO2 in the alumina matrix. The samples were sinter...

  15. Your Digestive System and How It Works

    Science.gov (United States)

    ... the GI tract, also called gut flora or microbiome, help with digestion. Parts of the nervous and circulatory systems also play roles in the digestive process. Together, a combination of nerves, hormones, bacteria, blood, and the organs ...

  16. The Liverpool Microwave Palaeointensity System

    Science.gov (United States)

    Hill, Mimi; Biggin, Andrew; Hawkins, Louise; Hodgson, Emma; Hurst, Elliot

    2016-04-01

    The motivation for the group at Liverpool in the 1990s (led by John Shaw and Derek Walton) to start experimenting with using microwaves to demagnetise and remagnetise palaeomagnetic samples, rather than heating using conventional ovens, was to reduce laboratory induced alteration in absolute palaeointensity experiments. As with other methods, the non-ideal effects of grain size and naturally altered remanence must still be addressed. From humble beginnings using a domestic microwave oven the current 4th generation microwave system (MWS) has developed in to an integrated combined 14 GHz microwave resonant cavity and SQUID magnetometer system. The MWS is designed to investigate one 5 mm diameter sample at a time with microwave exposure (the equivalent of a heating step in conventional experiments) ranging from a few seconds up to around a minute. Each experiment (protocol, checks, direction and strength of applied field, number of steps etc) can be tailored to the behaviour of each individual sample. There have been many published studies demonstrating the equivalence of conventional thermal (Thellier) and microwave techniques using both artificial and natural remanence and also that the microwave method can indeed reduce laboratory induced alteration. Here an overview of the present MWS including a discussion of the physical processes occurring will be given. Examples of current projects (both archaeological and geological) utilising the method will also be described. Finally, future developments and applications of the method will be discussed.

  17. Dental Procedures.

    Science.gov (United States)

    Ramponi, Denise R

    2016-01-01

    Dental problems are a common complaint in emergency departments in the United States. There are a wide variety of dental issues addressed in emergency department visits such as dental caries, loose teeth, dental trauma, gingival infections, and dry socket syndrome. Review of the most common dental blocks and dental procedures will allow the practitioner the opportunity to make the patient more comfortable and reduce the amount of analgesia the patient will need upon discharge. Familiarity with the dental equipment, tooth, and mouth anatomy will help prepare the practitioner for to perform these dental procedures.

  18. Digestion of carbohydrates in the pig.

    Science.gov (United States)

    Drochner, W

    1993-01-01

    A review of carbohydrate digestion in the pig is given. The cascade of digestion in the mouth, stomach, small and large intestine is described. Principles of enzymatic and fermentative digestion according to new results with fistulated animals are discussed. The efficacy and quality of fermentation in the large intestine depending on level and quality of carbohydrates in the diet are demonstrated. Some aspects of energetical efficacy of hindgut digestion are discussed. Dietetic effects of carbohydrates are described.

  19. Transforming Principal Preparation. ERIC Digest.

    Science.gov (United States)

    Lashway, Larry

    In the current climate of accountability, the responsibilities of principals have increased. The new role of principals requires new forms of training, and standards-based reform is generating major changes in principal-preparation programs. This digest examines some of those changes. First, it looks at the effectiveness of principal-preparation…

  20. Coaching for Tests. ERIC Digest.

    Science.gov (United States)

    Wildemuth, Barbara

    The term "coaching" applies to a variety of types of test preparation programs which vary in length, instructional method, and content. Most research on the effectiveness of coaching has examined the Scholastic Aptitude Test (SAT), a measure of academic abilities used to predict college performance. This ERIC Digest reviews studies of…