WorldWideScience

Sample records for ranges microwave ovens

  1. 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)

  2. 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…

  3. 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.

  4. 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,…

  5. 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…

  6. 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 ...

  7. 21 CFR 1030.10 - Microwave ovens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Microwave ovens. 1030.10 Section 1030.10 Food and... ovens. (a) Applicability. The provisions of this standard are applicable to microwave ovens manufactured after October 6, 1971. (b) Definitions. (1) Microwave oven means a device designed to heat, cook, or dry...

  8. Radiofrequency radiation leakage from microwave ovens.

    Science.gov (United States)

    Lahham, Adnan; Sharabati, Afifeh

    2013-12-01

    This work presents data on the amount of radiation leakage from 117 microwave ovens in domestic and restaurant use in the West Bank, Palestine. The study of leakage is based on the measurements of radiation emissions from the oven in real-life conditions by using a frequency selective field strength measuring system. The power density from individual ovens was measured at a distance of 1 m and at the height of centre of door screen. The tested ovens were of different types, models with operating powers between 1000 and 1600 W and ages ranging from 1 month to >20 y, including 16 ovens with unknown ages. The amount of radiation leakage at a distance of 1 m was found to vary from 0.43 to 16.4 μW cm(-2) with an average value equalling 3.64 μW cm(-2). Leakages from all tested microwave ovens except for seven ovens (∼6 % of the total) were below 10 μW cm(-2). The highest radiation leakage from any tested oven was ∼16.4 μW cm(-2), and found in two cases only. In no case did the leakage exceed the limit of 1 mW cm(-2) recommended by the ICNIRP for 2.45-GHz radiofrequency. This study confirms a linear correlation between the amount of leakage and both oven age and operating power, with a stronger dependence of leakage on age.

  9. Microwave Oven Repair. Teacher Edition.

    Science.gov (United States)

    Smreker, Eugene

    This competency-based curriculum guide for teachers addresses the skills a technician will need to service microwave ovens and to provide customer relations to help retain the customer's confidence in the product and trust in the service company that performs the repair. The guide begins with a task analysis, listing 20 cognitive tasks and 5…

  10. Combination microwave ovens: an innovative design strategy.

    Science.gov (United States)

    Tinga, Wayne R; Eke, Ken

    2012-01-01

    Reducing the sensitivity of microwave oven heating and cooking performance to load volume, load placement and load properties has been a long-standing challenge for microwave and microwave-convection oven designers. Conventional design problem and solution methods are reviewed to provide greater insight into the challenge and optimum operation of a microwave oven after which a new strategy is introduced. In this methodology, a special load isolating and energy modulating device called a transducer-exciter is used containing an iris, a launch box, a phase, amplitude and frequency modulator and a coupling plate designed to provide spatially distributed coupling to the oven. This system, when applied to a combined microwave-convection oven, gives astounding performance improvements to all kinds of baked and roasted foods including sensitive items such as cakes and pastries, with the only compromise being a reasonable reduction in the maximum available microwave power. Large and small metal utensils can be used in the oven with minimal or no performance penalty on energy uniformity and cooking results. Cooking times are greatly reduced from those in conventional ovens while maintaining excellent cooking performance.

  11. Behaviors of young children around microwave ovens.

    Science.gov (United States)

    Robinson, Marla R; O'Connor, Annemarie; Wallace, Lindsay; Connell, Kristen; Tucker, Katherine; Strickland, Joseph; Taylor, Jennifer; Quinlan, Kyran P; Gottlieb, Lawrence J

    2011-11-01

    Scald burn injuries are the leading cause of burn-related emergency room visits and hospitalizations for young children. A portion of these injuries occur when children are removing items from microwave ovens. This study assessed the ability of typically developing children aged 15 months to 5 years to operate, open, and remove the contents from a microwave oven. The Denver Developmental Screening Test II was administered to confirm typical development of the 40 subjects recruited. All children recruited and enrolled in this study showed no developmental delays in any domain in the Denver Developmental Screening Test II. Children were observed for the ability to open both a push and pull microwave oven door, to start the microwave oven, and to remove a cup from the microwave oven. All children aged 4 years were able to open the microwaves, turn on the microwave, and remove the contents. Of the children aged 3 years, 87.5% were able to perform all study tasks. For children aged 2 years, 90% were able to open both microwaves, turn on the microwave, and remove the contents. In this study, children as young as 17 months could start a microwave oven, open the door, and remove the contents putting them at significant risk for scald burn injury. Prevention efforts to improve supervision and caregiver education have not lead to a significant reduction in scald injuries in young children. A redesign of microwave ovens might prevent young children from being able to open them thereby reducing risk of scald injury by this mechanism.

  12. [Eye heating caused by microwave ovens].

    Science.gov (United States)

    Leitgeb, N; Tropper, K

    1993-01-01

    To clarify the question as to whether microwave ovens represent a risk for the eyes, a worst-case situation was investigated in which it was assumed that a child observes the internal heating process with its eyes as close to the door of a microwave oven as it is possible to get. As expected, heating of the eyes was observed, which, however, was caused mainly by the conventional heating process rather than by microwave radiation. Significant microwave heating was observed only when increased scattered radiation was simulated by inactivating the safety contacts and opening the door of the microwave oven. When the door is opened to a clearly visible gap width (2.3 cm), the contribution of the microwave component to the overall temperature increase of 5 degrees C after one hour of continuous exposure did not exceed 16%. Even at the maximum possible door gap width which just did not cause the oven to switch off automatically (2.6 cm), 15 minutes of continuous exposure contributed only 50% to the 2 degrees C temperature increase. On the basis of these results, damage to the eye through the use of microwave ovens can be excluded.

  13. A review of microwave oven safety.

    Science.gov (United States)

    Osepchuk, J M

    1978-03-01

    The microwave leakage from current microwave ovens, which are manufactured to meet government emission standards, is reviewed. Typical leakage values imply exposure values well below the most conservative exposure standards in the world. A review of recent developments discloses increasingly stringent government regulation along with advances in techniques for suppression of microwave leakage. The nature of the leakage field is described and studies relating emission to exposure are reviewed. Field survey data are reviewed and it is found that the overwhelming majority of certified ovens in the field show leakage well below permissible limits with an increasing degree of certainty as time goes on. The conclusion is that microwave ovens are not only just as safe as they were in 1973 but they are being accepted as safe under essentially equivalent emission regulations in various countries including those in Eastern Europe.

  14. 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...... in a microwave oven chamber....... 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...

  15. 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,

  16. Accelerated staining technique using kitchen microwave oven.

    Science.gov (United States)

    Mukunda, Archana; Narayan, T V; Shreedhar, Balasundhari; Shashidhara, R; Mohanty, Leeky; Shenoy, Sadhana

    2015-01-01

    Histopathological diagnosis of specimens is greatly dependent on good sample preparation and staining. Both of these processes is governed by diffusion of fluids and dyes in and out of the tissue, which is the key to staining. Diffusion of fluids can be accelerated by the application of heat that reduces the time of staining from hours to the minute. We modified an inexpensive model of kitchen microwave oven for staining. This study is an attempt to compare the reliability of this modified technique against the tested technique of routine staining so as to establish the kitchen microwave oven as a valuable diagnostic tool. Sixty different tissue blocks were used to prepare 20 pairs of slides for 4 different stains namely hematoxylin and eosin, Van Gieson's, 0.1% toluidine blue and periodic acid-Schiff. From each tissue block, two bits of tissues were mounted on two different slides. One slide was stained routinely, and the other stained inside a microwave. A pathologist evaluated the stained slides and the results so obtained were analyzed statistically. Microwave staining considerably cut down the staining time from hours to seconds. Microwave staining showed no loss of cellular and nuclear details, uniform-staining characteristics and was of excellent quality. The cellular details, nuclear details and staining characteristics of microwave stained tissues were better than or equal to the routine stained tissue. The overall quality of microwave-stained sections was found to be better than the routine stained tissue in majority of cases.

  17. Bonding PMMA microfluidics using commercial microwave ovens

    Science.gov (United States)

    Toossi, A.; Moghadas, H.; Daneshmand, M.; Sameoto, D.

    2015-08-01

    In this paper, a novel low-cost, rapid substrate-bonding technique is successfully applied to polymethyl methacrylate (PMMA) microfluidics bonding for the first time. This technique uses a thin intermediate metallic microwave susceptor layer at the interface of the bonding site (microchannels) which produces localized heating required for bonding during microwave irradiation. The metallic susceptor pattern is designed using a multiphysics simulation model developed in ANSYS Multiphysics software (high-frequency structural simulation (HFSS) coupled with ANSYS-Thermal). In our experiments, the required microwave energy for bonding is delivered using a relatively inexpensive, widely accessible commercial microwave oven. Using this technique, simple PMMA microfluidics prototypes are successfully bonded and sealed in less than 35 seconds with a minimum measured bond strength of 1.375 MPa.

  18. Investigation of an acute microwave-oven hand injury.

    Science.gov (United States)

    Dickason, W L; Barutt, J P

    1984-01-01

    A case of an acute microwave-oven injury is presented, demonstrating a selective radial hand neuropathy and chronic moderate dysesthesia with discussion of the potential mechanism of disease. Microwave characteristics, their spectrum of effects on biological structures, microwave-oven safety design, and the international controversy concerning nonionizing radiation research are described.

  19. 78 FR 7939 - Energy Conservation Program: Test Procedures for Microwave Ovens (Active Mode)

    Science.gov (United States)

    2013-02-04

    ... 430 Energy Conservation Program: Test Procedures for Microwave Ovens (Active Mode); Proposed Rule #0... Conservation Program: Test Procedures for Microwave Ovens (Active Mode) AGENCY: Office of Energy Efficiency and... mode energy use for microwave ovens, including both microwave-only ovens and convection microwave ovens...

  20. [Histochemical staining using silver salts using a microwave oven].

    Science.gov (United States)

    Balaton, A

    1987-01-01

    Some metallic impregnations--Fontana-Masson, Warthin-Starry, Grocott's methenamine silver, Grimelius' and Dieterle's stains have been modified to use a microwave oven. Microwave bombardment markedly reduces the staining times and produces a cleaner background.

  1. Assessment of heating rate and non-uniform heating in domestic microwave ovens.

    Science.gov (United States)

    Pitchai, Krishnamoorthy; Birla, Sohan L; Jones, David; Subbiah, Jeyamkondan

    2012-01-01

    Due to the inherent nature of standing wave patterns of microwaves inside a domestic microwave oven cavity and varying dielectric properties of different food components, microwave heating produces non-uniform distribution of energy inside the food. Non-uniform heating is a major food safety concern in not-ready-to-eat (NRTE) microwaveable foods. In this study, we present a method for assessing heating rate and non-uniform heating in domestic microwave ovens. In this study a custom designed container was used to assess heating rate and non-uniform heating of a range of microwave ovens using a hedgehog of 30 T-type thermocouples. The mean and standard deviation of heating rate along the radial distance and sector of the container were measured and analyzed. The effect of the location of rings and sectors was analyzed using ANOVA to identify the best location for placing food on the turntable. The study suggested that the best location to place food in a microwave oven is not at the center but near the edge of the turntable assuming uniform heating is desired. The effect of rated power and cavity size on heating rate and non-uniform heating was also studied for a range of microwave ovens. As the rated power and cavity size increases, heating rate increases while non-uniform heating decreases. Sectors in the container also influenced heating rate (p microwave ovens were inconsistent in producing the same heating patterns between the two replications that were performed 4 h apart.

  2. Pengeringan Lidah Buaya (AloVera Menggunakan Oven Gelombang Mikro (Microwave Oven

    Directory of Open Access Journals (Sweden)

    Edy Hartulistiyoso

    2011-10-01

    Full Text Available Aloe vera (Aloe vera is known as a useful plant, both as food, cosmetics or pharmaceuticals. Due its high water content, Aloe vera should be processed immediately after harvest. This paper will discuss the drying of aloe vera using microwave oven. The drying process of 50 gr Aloe vera gel and rind using 80 Watts microwave power completed in 140 minutes to reach the final moisture content of 7% wet basis. The drying process in microwave drying shows similar process to that of conventional drying. Dipolar rotation mechanism of water molecules at microwave drying does not affect the drying stage. It shows however shorter process time. The water removal of the drying material occurred in the early minutes until the 50th minute. This because of the high free water surface on the material, while from minute 50 to minute 140 slowed the drying process. Highest temperature of the material during the process is achieved at 57.6 oC in drying of gel and 70.7 oC in drying of Aloe vera rind. It is expected that there is no damage of nutritional content during drying in the this temperature range. Quality analysis of flour and tea of Aloe vera after drying by microwave showed that Aloe vera powder produced within the range of the standard, both visually and microbiologically, but indicated as low quality when viewed from acid content levels. Whether microwave heating mechanism affects the acidity, this needs further study.

  3. Rapid drying soils with microwave ovens.

    Science.gov (United States)

    2002-07-01

    Soils are normally dried in either a convection oven or stove. Inspections of field and laboratory moisture content testing indicated that the typical drying durations for a convection oven and stove were, 24 hours and 60 minutes, respectively. The o...

  4. Microwave Oven Experiments with Metals and Light Sources

    Science.gov (United States)

    Vollmer, Michael; Mollmann, Klaus-Peter; Karstadt, Detlef

    2004-01-01

    "Don't put metal objects in the microwave" is common safety advice. But why? Here we describe demonstration experiments involving placing household metallic objects in a microwave oven. These allow a better understanding of the interaction of microwaves with materials. Light bulbs and discharge lamps can also be used in instructive demonstrations.

  5. Microwave Oven and its Associated Health Concerns: Views of ...

    African Journals Online (AJOL)

    Up to 84.9% knew that exposure to microwave radiation was harmful to the health, but only 49.8%, 43.0% and 53.2% knew that the microwave oven worked by the emission of microwave radiation, could not cook foods evenly, and could interfere with a heart pace maker respectively. The overall knowledge was poor with a ...

  6. Modification of a Microwave Oven for Laboratory Use.

    Science.gov (United States)

    Andrews, Judith; Atkinson, George F.

    1984-01-01

    Discusses use of a domestic microwave oven for drying analytical samples with time savings compared to conventional ovens, providing a solution to the problem of loss of load as samples dry. Presents a system for examining emitted gases from drying process and reports results of several test dryings. (JM)

  7. A container for heat treating materials in microwave ovens

    Science.gov (United States)

    Holcombe, C.E.; Dykes, N.L.; Kimrey, H.D. Jr.; Mills, J.E.

    1988-01-26

    The efficiency of a microwave oven of a conventional two-source configuration and energy level is increased by providing the oven with a container for housing a refractory material to be treated. The container is formed to top and bottom walls transparent to microwaves while the sidewalls, in a circular configuration, are formed of a nonmetallic material opaque to microwave radiation for reflecting the radiation penetrating the top and bottom walls radially inwardly into the center of the container wherein a casket of heat-insulating material is provided for housing the material to be heat treated. The reflection of the microwave radiation from the sidewalls increases the concentration of the microwaves upon the material being heat treated while the concentration of the microwaves upon the material being heat treated while the casket retains the heat to permit the heating of the material to a substantially higher temperature than achievable in the oven without the container.

  8. 5 Tips for Using Your Microwave Oven Safely

    Science.gov (United States)

    ... produced by these ovens—are a type of electromagnetic radiation. These waves cause water molecules in food ... being emitted in this situation.” How to Report Problems In the FDA’s experience, most microwave ovens that ...

  9. Surveys of Microwave Ovens in U.S. Homes

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Alison [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Yang, Hung-Chia Dominique [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Beraki, Bereket [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Desroches, Louis-Benoit [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Young, ScottJ. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ni, Chun Chun [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Willem, Henry [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Whitehead, Camilla Dunham [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Donovan, Sally M. [Consultant, Melbourne (Australia)

    2012-12-01

    The U.S. Department of Energy (DOE) is conducting test procedure and energy conservation standard rulemakings for microwave ovens. These units generally offer a “convection,” “bake,” or “combo” cooking mode on the user interface. DOE divides products under analysis into classes by the type of energy used, capacity, or other performance-related features that affect consumer utility and efficiency. Installation types are grouped as (1) countertop and (2) built-in and over-the-range. The following sub-sections summarize the existing data as well as the specific data LBNL obtained with surveys.

  10. Characteristics of frozen colostrum thawed in a microwave oven

    Energy Technology Data Exchange (ETDEWEB)

    Jones, L.R.; Taylor, A.W.; Hines, H.C.

    1987-09-01

    Use of a microwave oven to thaw frozen colostrum was evaluated. Colostrum was collected from nine cows, four of which were immunized to produce specific colostral antibodies. Colostrum from each cow was frozen, subsequently thawed, and pooled. One-liter aliquots of the pooled colostrum were frozen and assigned randomly to three thawing treatments. Colostrum was thawed using one of three regimens: 10 min in a microwave oven at full power (650 W), 17 min in a microwave oven at half power (325 W), and 25 min in 45 degrees C water. Colostrum thawed in the microwave oven was slightly coagulated and had lower volume and total protein content than colostrum thawed in water. Casein and pH were not different among treatments. Both concentration and total content of immunoglobulin A were higher in the control than in microwave treatments. Neither amount nor concentration of immunoglobulin G and immunoglobulin M were different among treatments. Immunological activity, measured by a hemolytic test, was lower for microwave treatments than the control but did not differ between microwave treatments. Frozen colostrum thawed in a microwave oven should provide a reasonable source of colostrum when fresh high quality colostrum is not available.

  11. Risk of Burns from Eruptions of Hot Water Overheated in Microwave Ovens

    Science.gov (United States)

    ... Burns from Eruptions of Hot Water Overheated in Microwave Ovens Share Tweet Linkedin Pin it More sharing options ... after it had been over-heated in a microwave oven. Over-heating of water in a cup can ...

  12. Comparison of two methods for determination of tomato paste solids: vacuum oven versus microwave oven.

    Science.gov (United States)

    Jazaeri, Sahar; Kakuda, Yukio; Gismondi, Stephen; Wigle, Doug G

    2011-01-01

    Two analytical procedures used to determine total, soluble, and insoluble solids in tomato paste were evaluated. The microwave oven (MO) method was compared to the vacuum oven (VO) method. The VO method is tedious and measured the three solids fractions in the paste directly, while the MO method measured the total solids directly but used an equation to calculate the water-soluble and -insoluble solids. The MO method was faster and less labor-intensive, and yielded small but statistically significant higher values for total and insoluble solids and lower statistically significant values for soluble solids.

  13. 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... supplemental notice of proposed rulemaking (SNOPR) to amend the test procedures for microwave ovens. That SNOPR... for measuring the standby mode and off mode energy use of products that combine a microwave oven with...

  14. 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...

  15. Microwave oven-induced decalcification at varying temperatures: A ...

    African Journals Online (AJOL)

    This study was designed to evaluate the effect of decalcifying fluid types on bone tissue architecture and its staining properties following decalcification at varying temperatures. A decalcification methodology using Golding and Stewards (GS) fluid, and Jenkings fluid (JK), and a modern household microwave oven to ...

  16. A conventional microwave oven for denture cleaning: a critical review.

    Science.gov (United States)

    Brondani, Mario Augusto; Samim, Firoozeh; Feng, Hong

    2012-06-01

    Denture cleaning should be quick and easy to perform, especially in long-term care facilities. The lack of proper oral hygiene can put older adults at higher risk from opportunistic oral infections, particularly fungal. As an alternative to regular brushing, the use of a microwave oven has been suggested for cleaning and disinfecting dentures. To synthesise and discuss the advantages and disadvantages of the use of a conventional microwave oven for cleaning and disinfecting complete dentures. A brief literature search focused on papers dealing with microwave therapy for denture cleaning through PubMed Central, Cochrane Database of Systematic Reviews, Google Scholar, Ovid MEDLINE(R) In-Process, and Scifinder Scholar. One hundred and sixty-seven manuscripts published in English with full text were found, and 28 were accepted and discussed in the light of the advantages and disadvantages of the use of conventional microwave oven for cleaning and disinfecting complete dentures. There was no standardisation for microwave use for denture cleaning. Manual cleaning still seemed to be the optimal method for controlling fungal infection and denture stomatitis. However, such a daily routine appeared to be underused, particularly in long-term care facilities. © 2010 The Gerodontology Society and John Wiley & Sons A/S.

  17. Thermodynamics of Water Superheated in the Microwave Oven

    Science.gov (United States)

    Erné, B. H.

    2000-10-01

    A simple visual demonstration is proposed that provokes thinking about the elementary thermodynamics of heating and boiling. Water is conveniently heated above its normal boiling point in a microwave oven in a glass microwave oven teapot. Water stops boiling soon after heating is interrupted, but subsequently added rough particles can still act as nucleation centers for a brief, spectacular burst of steam bubbles. The heat to make those steam bubbles obviously comes from the water itself, so that one can conclude that the boiling water was superheated, which is confirmed with a thermometer. Besides illustrating chemical thermodynamics, the demonstration also shows why safety precautions are usually taken in the laboratory to prevent superheating. Details of the observations are discussed by giving background on the nucleation of steam bubbles.

  18. 75 FR 42612 - Energy Conservation Program for Consumer Products: Test Procedure for Microwave Ovens

    Science.gov (United States)

    2010-07-22

    ... does as well, that can work as a microwave only, work as a convection oven, or in combination and... Ovens AGENCY: Office of Energy Efficiency and Renewable Energy, Department of Energy. ACTION...) issued a notice of proposed rulemaking (NOPR) in which DOE proposed test procedures for microwave ovens...

  19. Microwave-induced plasma reactor based on a domestic microwave oven for bulk solid state chemistry

    Science.gov (United States)

    Brooks, David J.; Douthwaite, Richard E.

    2004-12-01

    A microwave-induced plasma (MIP) reactor has been constructed from a domestic microwave oven (DMO) and applied to the bulk synthesis of solid state compounds. Low pressure MIP can be initiated and maintained using a range of gases including Ar, N2, NH3, O2, Cl2, and H2S. In order to obtain reproducible synthesis conditions the apparatus is designed to allow control of gas flow rate, gas composition, and pressure. The use of the reactor is demonstrated by the synthesis of three binary metal nitrides formed in a NH3 MIP. The reactions are rapid and the products show good crystallinity and phase purity as judged by powder x-ray diffraction.

  20. Tensile strength of type IV dental stones dried in a microwave oven.

    Science.gov (United States)

    Hersek, Nur; Canay, Senay; Akça, Kivanç; Ciftçi, Yalçin

    2002-05-01

    It is known that drying dental stones in a microwave oven can save time, but the strength of the material may be affected by different drying methods. This study evaluated the diametral tensile strength (DTS) of 5 type IV gypsum products at different time intervals using microwave and air-drying methods. . A total of 300 cylinder specimens were prepared from 5 type IV dental stones (Moldano, Amberok, Herastone, Shera-Sockel, and Fujirock; n = 60 per stone) in accordance with the manufacturers' recommendations. Half of the specimens of each stone (n = 30) were dried in open air within a temperature range of 20 +/- 2 degrees C; the other half (n = 30) underwent initial setting in a silicone rubber mold in open air for 10 minutes and then were dried in a microwave oven for 10 minutes. Within these groups, 10 specimens were tested under diametral compression at each of the following time periods: 30, 60, and 120 minutes after drying. Three-way analysis of variance and Scheffe's post hoc test were performed for statistical comparisons at a significance level of Pmicrowave oven (mean 2.99 MPa) were significantly higher (Pmicrowave oven drying had a positive effect on the diametral tensile strength of 5 type IV dental stones.

  1. Microwave oven injuries in patients with complex partial seizures.

    Science.gov (United States)

    DeToledo, John C; Lowe, Merredith R

    2004-10-01

    Microwave ovens are often recommended as a safe cooking alternative for persons with epilepsy. We report four patients who suffered serious burns to their hands while handling microwave-heated liquids during a complex partial seizure (CPS). Injuries were due to the contact of the skin with a very hot container. The fact that all patients held on to the hot containers despite being burned and that they did not remember experiencing any pain at the time of the accident indicates that neither high temperatures nor pain will prevent patients who are having a CPS from suffering this type of injury. Unfortunately, there is no foolproof way to prevent the individual from opening the oven and removing its contents during a CPS. The only solution for this problem is "prevention"-individuals with poorly controlled CPS should be cautioned about these risks. The use of microwave settings that permit the heating but not boiling of liquids and the use of gloves while heating food and liquids to scalding temperatures may minimize the risk of this type of injury.

  2. Rapid in situ hybridization using digoxigenin probe and microwave oven.

    Science.gov (United States)

    Besançon, R; Bencsik, A; Voutsinos, B; Belin, M F; Févre-Montange, M

    1995-11-01

    In situ hybridization has been developed with probes labelled with a non-radioactive nucleotide, especially digoxigenin-coupled nucleotides. These non-radioactive probes significantly reduce safety problems and experimentation time. In this paper, we have studied by in situ hybridization the messenger RNA (mRNA) of the neuropeptide pro-opiomelanocortin (POMC), in the rat pituitary gland using digoxigenin labelled oligonucleotide and a microwave oven. Our protocol permitted us to visualize POMC mRNA in all cells of the intermediate lobe and a few corticotroph cells in the anterior lobe, as it has been already demonstrated and to complete the experiment in less than 24 hrs.

  3. Microwave sintering of sol-gel composite films using a domestic microwave oven

    Science.gov (United States)

    Kobayashi, Makiko; Matsumoto, Makoto

    2016-07-01

    Feasibility study of sol-gel composite microwave sintering using a domestic microwave oven was carried out. Two kinds of lead zirconate titanate (PZT) powders were mixed with PZT sol-gel solution and the mixture was sprayed onto 3-mm-thick titanium substrate. The films were sintered by 700 W domestic oven for 10 min. Ultrasonic measurement was carried out in pulse-echo mode and clear multiple echoes were confirmed. It would be suitable method to fabricate high frequency broadband focused ultrasonic transducers. Further research is required to improve sintering degree.

  4. Microwave oven: how to use it as a crystalloid fluid warmer.

    Science.gov (United States)

    Chittawatanarat, Kaweesak; Akanitthaphichat, Siriwasan

    2009-11-01

    Hypothermia is a common complication in the hypovolemic patient. Warm intravenous fluids have proven valuable at preventing this complication during volume replacement. The microwave oven is considered an applicable alternative method for warming fluids but no protocol has been established. To evaluate the efficacy and affected variables of the microwave oven in warming crystalloid fluids and to determine the appropriate formula for calculating the warming duration. The important variables influencing the operation of the microwave oven include the difference between the crystalloid fluid and room temperature, the microwave oven's capability, variations in microwave irradiation, and fluid shaking. The appropriate formula for calculating warming duration is: Duration (sec) = Volume (cc) x 4.2j.g(-1).K(-1) x Raised temperature DeltaT (K) x 1.1 (Adjusted power) / Mivcwrowave power (W). The microwave oven is a safe and practical method for warming crystalloid fluids.

  5. Effect of plant extracts on physicochemical properties of chicken breast meat cooked using conventional electric oven or microwave.

    Science.gov (United States)

    Rababah, T M; Ereifej, K I; Al-Mahasneh, M A; Al-Rababah, M A

    2006-01-01

    This study evaluated effects of vacuum-infused fresh chicken breast meats with grape seed extracts, green tea extracts, or tertiary butyl hydroquinone on pH, texture, color, and thiobarbituric reactive substances after cooking using a microwave or conventional electric oven for 12 d storage at 5 degrees C. Thiobarbituric reactive substances values of uncooked (raw) chicken breast meats for 0 to 12 d of storage ranged from 1.12 to 3.5 mg of malonaldehyde/100 g of chicken. During 0 to 12 d of storage, thiobarbituric reactive substances values ranged from 2.50 to 7.80 and from 2.4 to 7.35 mg of malonaldehyde/100 g of chicken breast meat cooked by microwave and conventional electric oven, respectively. Meats cooked by microwave had higher redness and lower lightness values than those cooked by conventional electric oven. Also, meats cooked by microwave had higher maximum shear force, working of shear, hardness, springiness, cohesiveness, and chewiness values than meats cooked by conventional electric oven. Tertiary butyl hydroquinone was the most effective in raw and cooked meats in reducing lipid oxidation, followed by grape seed and green tea extracts. Plant extracts are effective in preventing undesirable changes in chemical properties in chicken breast meat caused by microwave and conventional electric oven cooking.

  6. [Antigen retrieval by microwave oven with buffer of citric acid].

    Science.gov (United States)

    Pellicer, E M; Sundblad, A

    1994-01-01

    Microwave oven (mwo) is used to stimulate tissue fixation and to retrieve antigens damaged by fixation. Heavy metal salt solutions, water, and citric acid buffer (cab) have been suggested for this purpose. A serie of tumors treated with cab and phosphate-buffered saline (pbs) with mwo were studied immunohistochemically with 24 antibodies. Controls were treated in the same way, except for microwaving. The antibodies were directed against antigens of the following tumors: breast and prostate carcinoma, carcinoid, lymphoma and melanoma. The results showed that cab enhanced the immunoreactivity of the following antigens: estrogen receptors (AMAC), progesterone receptors (Novocastra), HMB45, vimentin, leukocyte common antigen, PCNA, p53, MIB-1 (Ki-67) and prostatic specific antigen. The antigens that did not improve their immunoreactivity, when compared with the control series were: factor VIII, keratin, Leu 22, L26, neuron-specific enolase, CEA, chromogranin, HBME-1, smooth muscle actin and EMA. Microwaving equally improved protein S100 and desmin either with cab or pbs. The only antigen that improved with pbs was actin. The results with B72.3 and NKI/C3 were poor and not reliable. In conclusion microwaving with cab enhances the immunoreactivity of the antibodies mentioned above leading to an increase in sensibility without loosing specificity.

  7. 76 FR 72332 - Energy Conservation Program: Test Procedure for Microwave Ovens

    Science.gov (United States)

    2011-11-23

    ... the November 2007 ANOPR) concerning energy conservation standards for commercial clothes washers and... conservation standards rulemaking. AHAM commented that it opposes the inclusion of thermal elements designed... including microwave ovens with thermal elements in the definition of microwave ovens, that same unworkable...

  8. Oro-facial thermal injury caused by food heated in a microwave oven.

    Science.gov (United States)

    Wakefield, Yasha; Pemberton, Michael N

    2009-01-01

    Burns to the oral mucosa usually result from the accidental ingestion of hot food or beverages. The burns are usually of short duration and little consequence. The widespread use of microwave ovens, however, has added a new dimension to the problem. Microwave ovens heat food much quicker than a conventional oven, but they produce uneven heating within the food and extremely high temperatures can be reached. We describe two cases of patients who suffered inadvertent injury to the oral mucosa from the ingestion of microwave-heated food.

  9. Microwave chemistry: Effect of ions on dielectric heating in microwave ovens

    Directory of Open Access Journals (Sweden)

    Jamil Anwar

    2015-01-01

    Full Text Available To understand the interactions of microwaves with dielectric materials and their conversion to thermal energy in aqueous systems, the effect of ionic concentration has been studied. Aqueous solutions of inorganic ions were exposed to microwaves (2.45 GHz in a modified oven under identical conditions. Difference in solution temperatures with reference to pure (deionized water was monitored in each case. A significant decrease in the temperature was observed with an increase in the quantity of ions. Experiments were repeated with several inorganic ions varying in size and charge. The information can be helpful in understanding the role of ions during dielectric heating.

  10. 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 stated...

  11. Cost-effective single-step carbon nanotube synthesis using microwave oven

    Science.gov (United States)

    Algadri, Natheer A.; Ibrahim, K.; Hassan, Z.; Bououdina, M.

    2017-08-01

    This paper reports the characterization of carbon nanotubes (CNTs) synthesised using a conventional microwave oven method, offering several advantages including fast, simple, low cost, and solvent free growth process. The procedure involves flattening of graphite/ferrocene mixture catalyst inside the microwave oven under ambient conditions for a very short duration of 5 s, which inhibits the loss factor of graphite and ferrocene. The effect of graphite/ferrocene mixture ratio for the synthesis of CNTs is investigated by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), x-ray diffraction (XRD), Raman spectroscopy and UV-NIR-Vis measurements. The samples produced using the different ratios contain nanotubes with an average diameter in the range 44-79 nm. The highest yield of CNTs is attained with graphite/ferrocene mixture ratio of 70:30. The lowest I D/I G ratio intensity as identified by Raman spectroscopy for 70:30 ratio indicates the improved crystallinity of CNTs. Due to the capillary effect of CNTs, Fe nanoparticles are found to be encapsulated inside the tubes at different positions along the tube length. The obtained results showed that the smaller the diameter of graphite and ferrocene favors the synthesis of graphene oxide upon microwave radiation.

  12. Drying kinetics of apricot halves in a microwave-hot air hybrid oven

    Science.gov (United States)

    Horuz, Erhan; Bozkurt, Hüseyin; Karataş, Haluk; Maskan, Medeni

    2017-06-01

    Drying behavior and kinetics of apricot halves were investigated in a microwave-hot air domestic hybrid oven at 120, 150 and 180 W microwave power and 50, 60 and 70 °C air temperature. Drying operation was finished when the moisture content reached to 25% (wet basis) from 77% (w.b). Increase in microwave power and air temperature increased drying rates and reduced drying time. Only falling rate period was observed in drying of apricot halves in hybrid oven. Eleven mathematical models were used for describing the drying kinetics of apricots. Modified logistic model gave the best fitting to the experimental data. The model has never been used to explain drying behavior of any kind of food materials up to now. Fick's second law was used for determination of both effective moisture diffusivity and thermal diffusivity values. Activation energy values of dried apricots were calculated from Arrhenius equation. Those that obtained from effective moisture diffusivity, thermal diffusivity and drying rate constant values ranged from 31.10 to 39.4 kJ/mol, 29.56 to 35.19 kJ/mol, and 26.02 to 32.36 kJ/mol, respectively.

  13. Survivability of Salmonella cells in popcorn after microwave oven and conventional cooking.

    Science.gov (United States)

    Anaya, I; Aguirrezabal, A; Ventura, M; Comellas, L; Agut, M

    2008-01-01

    The survivability of Salmonella cells in popcorn preparation was determined for two distinct cooking methods. The first method used a standard microwave oven. The second method used conventional cooking in a pan. Prior to thermal processing in independent experiments, 12 suspensions in a range between 1x10(3) and 8x10(6) colony-forming units (CFU) per gram of Salmonella cells were inoculated in both raw microwave popcorn and conventional corn kernels. The influence of the initial concentration of Salmonella cells in the raw products and the lethal effects on Salmonella by thermal treatments for cooking were studied. Survival of Salmonella cells was determined in the thermally processed material by pre-enrichment and enrichment in selective medium, in accordance with the legislation for expanded cereals and cereals in flakes. Viable experimental contaminants were recovered from the conventionally cooked popcorn with initial inoculation concentrations of 9x10(4)cells/g or greater. Salmonella cell viability was significantly reduced after microwave oven treatment, with recoveries only from initial concentrations of 2x10(6)cells/g or superior.

  14. Optimization of pretreatments and process parameters for sorghum popping in microwave oven using response surface methodology.

    Science.gov (United States)

    Mishra, Gayatri; Joshi, Dinesh C; Mohapatra, Debabandya

    2015-12-01

    Sorghum is a popular healthy snack food. Popped sorghum was prepared in a domestic microwave oven. A 3 factor 3 level Box and Behneken design was used to optimize the pretreatment conditions. Grains were preconditioned to 12-20 % moisture content by the addition of 0-2 % salt solutions. Oil was applied (0-10 % w/w) to the preconditioned grains. Optimization of the pretreatments was based on popping yield, volume expansion ratio, and sensory score. The optimized condition was found at 16.62 % (wb), 0.55 % salt and 10 % oil with popping yield of 82.228 %, volume expansion ratio of 14.564 and overall acceptability of 8.495. Further, the microwave process parameters were optimized using a 2 factor 3 level design having microwave power density ranging from 9 to 18 W/g and residence time ranging from 100 to 180 s. For the production of superior quality pop sorghum, the optimized microwave process parameters were microwave power density of 18 Wg(-1) and residence time of 140 s.

  15. Color and volatile analysis of peanuts roasted using oven and microwave technologies.

    Science.gov (United States)

    Smith, Alicia L; Barringer, Sheryl A

    2014-10-01

    Roasted peanut color and volatiles were evaluated for different time and temperature combinations of roasting. Raw peanuts were oven roasted at 135 to 204 °C, microwave roasted for 1 to 3 min, or combination roasted by microwave and oven roasting for various times and temperatures. Volatiles were measured using selected ion flow tube mass spectrometry. L* values were used to categorize peanuts as under-roasted, ideally roasted, and over-roasted. The total roasting time in order to achieve ideal color was not shortened by most of the combination treatments compared to their oven roasted equivalents. Oven before microwave roasting compared to the reverse was found to significantly increase the L* value. Peanuts with the same color had different volatile levels. Hexanal concentrations decreased then increased with roasting. Pyrazine levels increased as roasting time increased, although oven at 177 °C treatments had the highest and microwave treatments had the lowest levels. Volatile levels generally increased as roasting time or temperature increased. Oven 177 °C for 15 min generally had the highest level of volatiles among the roasting treatments tested. Soft independent modeling of class analogies based on volatile levels showed that raw peanuts were the most different, commercial samples were the most similar to each other, and oven, microwave, and combination roasting were all similar in volatile profile. Peanuts can be roasted to equivalent colors and have similar volatile levels by different roasting methods. Oven and microwave roasting technologies produced the same roasted peanut color and had similar volatile trends as roasting time increased. Combination roasting also produced ideal color and similar volatile levels indicating that microwave technology could be further explored as a peanut roasting technique. © 2014 Institute of Food Technologists®

  16. Analysis of standard reference materials following digestion using a modified appliance grade microwave oven

    Science.gov (United States)

    Schaumloffel, John C.; Siems, William F.

    1996-12-01

    Microwave digestion provides a rapid means of sample preparation in the analytical laboratory. The major disadvantage of this method is the high cost of commercial microwave digestion systems. Modifications to the magnetron timing circuits of an appliance grade oven to make it suitable for sealed vessel microwave digestion are reported. The oven was modified without alteration to the irradiation cavity, and all initial safety features remain intact. Following digestion with the modified oven, NIST Standard Reference Materials (SRMs) were analyzed by inductively coupled plasma emission spectroscopy. The analytical data are similar to the certified concentrations in the SRMs, indicating that the modified oven provides a durable, rapid, cost-effective means of sample preparation.

  17. Frequency Distribution in Domestic Microwave Ovens and Its Influence on Heating Pattern.

    Science.gov (United States)

    Luan, Donglei; Wang, Yifen; Tang, Juming; Jain, Deepali

    2017-02-01

    In this study, snapshots of operating frequency profiles of domestic microwave ovens were collected to reveal the extent of microwave frequency variations under different operation conditions. A computer simulation model was developed based on the finite difference time domain method to analyze the influence of the shifting frequency on heating patterns of foods in a microwave oven. The results showed that the operating frequencies of empty and loaded domestic microwave ovens varied widely even among ovens of the same model purchased on the same date. Each microwave oven had its unique characteristic operating frequencies, which were also affected by the location and shape of the load. The simulated heating patterns of a gellan gel model food when heated on a rotary plate agreed well with the experimental results, which supported the reliability of the developed simulation model. Simulation indicated that the heating patterns of a stationary model food load changed with the varying operating frequency. However, the heating pattern of a rotary model food load was not sensitive to microwave frequencies due to the severe edge heating overshadowing the effects of the frequency variations. © 2016 Institute of Food Technologists®.

  18. Survival of Listeria spp. on raw whole chickens cooked in microwave ovens.

    Science.gov (United States)

    Farber, J M; D'Aoust, J Y; Diotte, M; Sewell, A; Daley, E

    1998-11-01

    The prevalence of microwave ovens in North American homes has increased dramatically within the last decade. Although microwave ovens are primarily used for reheating of foods, they are now more commonly being applied to the cooking of raw foods. Although cooking of raw foods, according to manufacturers' instructions targets an organoleptically acceptable end product, the process does not address the microbiological safety of the cooked food. Seventeen microwave ovens from various commercial suppliers were used to cook naturally contaminated whole raw broilers ( 1.8 kg) according to manufacturers' instructions. Temperature probes (six per chicken) were used to measure the temperature of chickens immediately after cooking and during the holding period. Of 81 Listeria-positive raw broilers and 93 raw roasters, 1 (1.2%) and 9 (9.7%), respectively, yielded viable Listeria spp. after microwave cooking. Of these, two were undercooked (visual inspection), one was over the maximum weight stipulated by the oven manufacturer and another one was over the maximum weight and undercooked. A significantly greater proportion of contaminated cooked birds was observed with roasters than with broilers, where for one of these contaminated roasters, the temperature at all six measured sites was > or = 87 degrees C. Most of the postcook Listeria-positive birds were associated with 2 of the 17 microwave ovens. Factors such as wattage, cavity size, and the presence or absence of a turntable seemingly did not play a significant role in the survival of Listeria spp. in microwave-cooked chicken. However, the general inability of microwave ovens to uniformly heat chicken carcasses was noted. In order to promote greater safety of microwave-cooked foods, general recommendations for consumers are provided.

  19. Oil content and fatty acid composition of eggs cooked in drying oven, microwave and pan.

    Science.gov (United States)

    Juhaimi, Fahad Al; Uslu, Nurhan; Özcan, Mehmet Musa

    2017-01-01

    In this study, the effect of heating on the oil yield and fatty acid composition of eggs cooked in drying oven, microwave oven, pan and boiled were determined, and compared. The highest oil content (15.22%) was observed for egg cooked in drying oven, while the lowest oil (5.195%) in egg cooked in pan. The cooking in microwave oven caused a decrease in oleic acid content (46.201%) and an increase in the amount of palmitic acid content (26.862%). In addition, the maximum oleic acid (65.837%) and minimum palmitic acid (14.015%) contents were observed in egg oil cooked in pan. Results showed that fatty acids were significantly affected by cooking method. This study confirms that the cooking processing influences the fatty acid composition of egg oils.

  20. Comparison of porcelain surface and flexural strength obtained by microwave and conventional oven glazing.

    Science.gov (United States)

    Prasad, Soni; Monaco, Edward A; Kim, Hyeongil; Davis, Elaine L; Brewer, Jane D

    2009-01-01

    Although the superior qualities of microwave technology are common knowledge in the industry, effects of microwave glazing of dental ceramics have not been investigated. The purpose of this study was to investigate the surface roughness and flexural strength achieved by glazing porcelain specimens in a conventional and microwave oven. Thirty specimens of each type of porcelain (Omega 900 and IPS d.Sign) were fabricated and sintered in a conventional oven. The specimens were further divided into 3 groups (n=10): hand polished (using diamond rotary ceramic polishers), microwave glazed, and conventional oven glazed. Each specimen was evaluated for surface roughness using a profilometer. The flexural strength of each specimen was measured using a universal testing machine. A 2-way ANOVA and Tukey HSD post hoc analysis were used to determine significant intergroup differences in surface roughness (alpha=.05). Flexural strength results were also analyzed using 2-way ANOVA, and the Weibull modulus was determined for each of the 6 groups. The surfaces of the specimens were subjectively evaluated for cracks and porosities using a scanning electron microscope (SEM). A significant difference in surface roughness was found among the surface treatments (P=.02). Follow-up tests showed a significant difference in surface roughness between oven-glazed and microwave-glazed treatments (P=.02). There was a significant difference in flexural strength between the 2 porcelains (Pmicrowave-glazed group was the highest (1.9) as compared to the other groups. The surface character of microwave-glazed porcelain was superior to oven-glazed porcelain. Omega 900 had an overall higher flexural strength than IPS d.Sign. Weibull distributions of flexural strengths for Omega 900 oven-glazed and microwave-glazed specimens were similar. SEM analysis demonstrated a greater number of surface voids and imperfections in IPS d. Sign as compared to Omega 900.

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Peio Lopez-Iturri

    2015-01-01

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

  3. Evaluation of microwave oven heating for prediction of drug-excipient compatibilities and accelerated stability studies.

    Science.gov (United States)

    Schou-Pedersen, Anne Marie V; Østergaard, Jesper; Cornett, Claus; Hansen, Steen Honoré

    2015-05-15

    Microwave ovens have been used extensively in organic synthesis in order to accelerate reaction rates. Here, a set up comprising a microwave oven combined with silicon carbide (SiC) plates for the controlled microwave heating of model formulations has been applied in order to investigate, if a microwave oven is applicable for accelerated drug stability testing. Chemical interactions were investigated in three selected model formulations of drug and excipients regarding the formation of ester and amide reaction products. In the accelerated stability studies, a design of experiments (DoE) approach was applied in order to be able to rank excipients regarding reactivity: Study A: cetirizine with PEG 400, sorbitol, glycerol and propylene glycol. Study B: 6-aminocaproic acid with citrate, acetate, tartrate and gluconate. Study C: atenolol with citric, tartaric, malic, glutaric, and sorbic acid. The model formulations were representative for oral solutions (co-solvents), parenteral solutions (buffer species) and solid dosage forms (organic acids applicable for solubility enhancement). The DoE studies showed overall that the same impurities were generated by microwave oven heating leading to temperatures between 150°C and 180°C as compared to accelerated stability studies performed at 40°C and 80°C using a conventional oven. Ranking of the reactivity of the excipients could be made in the DoE studies performed at 150-180°C, which was representative for the ranking obtained after storage at 40°C and 80°C. It was possible to reduce the time needed for drug-excipient compatibility testing of the three model formulations from weeks to less than an hour in the three case studies. The microwave oven is therefore considered to be an interesting alternative to conventional thermal techniques for the investigation of drug-excipient interactions during preformulation. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Microwave oven-related injuries treated in hospital EDs in the United States, 1990 to 2010.

    Science.gov (United States)

    Thambiraj, Dana F; Chounthirath, Thiphalak; Smith, Gary A

    2013-06-01

    The widespread availability of microwave ovens has sparked interest in injuries resulting from their use. Using a retrospective cohort design, the objective of this study is to investigate the epidemiology of microwave oven-related injuries treated in United States emergency departments (EDs) from 1990 through 2010 by analyzing data from the National Electronic Injury Surveillance System. An estimated 155959 (95% confidence interval [CI], 133515-178402) individuals with microwave oven-related injuries were treated in US hospital EDs from 1990 through 2010, which equals an average of 21 individuals per day; 60.7% were female; 63.3% were adults (≥18 years); 98.1% of injury events occurred at home; and 3.9% of patients were hospitalized. During the 21-year study period, the number and rate of microwave oven-related injuries increased significantly by 93.3% and 50.0%, respectively. The most common mechanism of injury was a spill (31.3%), and the most common body region injured was the hand and fingers (32.4%). Patients younger than 18 years were more likely to sustain an injury to their head and neck (relative risk: 1.65; 95% CI, 1.39-1.96) than adults. To our knowledge, this is the first study to investigate microwave oven-related injuries on a national scale. Microwave ovens are an important source of injury in the home in the United States. The large increases in the number and rate of these injuries underscore the need for increased prevention efforts, especially among young children. Copyright © 2013 Elsevier Inc. All rights reserved.

  5. 75 FR 42611 - Energy Conservation Program for Consumer Products: Test Procedure for Microwave Ovens

    Science.gov (United States)

    2010-07-22

    ..., Energy Efficiency and Renewable Energy, Building Technologies Program, EE-2J, 1000 Independence Avenue... Procedure for Microwave Ovens AGENCY: Office of Energy Efficiency and Renewable Energy, Department of Energy... of Energy, Forrestal Building, Room 8E-089, 1000 Independence Avenue, SW., Washington, DC 20585-0121...

  6. Computer-Presented Video Prompting for Teaching Microwave Oven Use to Three Adults with Developmental Disabilities

    Science.gov (United States)

    Sigafoos, Jeff; O'Reilly, Mark; Cannella, Helen; Upadhyaya, Megha; Edrisinha, Chaturi; Lancioni, Giulio E.; Hundley, Anna; Andrews, Alonzo; Garver, Carolyn; Young, David

    2005-01-01

    We evaluated the use of a video prompting procedure for teaching three adults with developmental disabilities to make popcorn using a microwave oven. Training, using a 10-step task analysis, was conducted in the kitchen of the participant's vocational training program. During baseline, participants were instructed to make popcorn, but were given…

  7. Use of a Microwave Oven. Youth Training Scheme. Core Exemplar Work Based Project.

    Science.gov (United States)

    Further Education Staff Coll., Blagdon (England).

    This trainer's guide is intended to assist supervisors of work-based career training projects in helping students understand the benefits, advantages, and disadvantages of a microwave oven and its use. The guide is one in a series of core curriculum modules that is intended for use in combination on- and off-the-job programs to familiarize youth…

  8. Thermal oxidation of rice bran oil during oven test and microwave heating.

    Science.gov (United States)

    Mishra, Richa; Sharma, Harish K; Sarkar, Bhavesh C; Singh, Charanjiv

    2012-04-01

    The purpose of the present study was to evaluate the oxidative stability of physically refined rice bran oil (RBO) under oven heating at 63 °C and microwave heating conditions by absorptivity. Oil samples with tertiary-butylhydroquinone (TBHQ) (100 ppm and 200 ppm), citric acid (CA), butylhydroxyanisole/butylhydroxytoluene (BHA/BHT) and in other combination, BHA/BHT+CA were submitted to oven test for 6 days, and the linear coefficient of correlation between peroxide value and absorptivity at 232 nm was determined. The gradual increase in peroxide value and absorptivity at 232 nm was observed in all the RBO samples, control and antioxidant added. RBO samples added with tertiary-butylhydroquinone (TBHQ) had shown the least peroxide value and absorptivity as 6.10 and 5.8 respectively, when added at a concentration of 200 ppm whereas; the control RBO samples had shown the maximum values. The peroxide values obtained from the correlations during the oven test were found closely correlated with the peroxide values obtained during the microwave oven heating experimentally. The effect of microwave heating on the oryzanol content and p-anisidine value was also observed and the correlation to the oven test was established. The oryzanol content and p-anisidine values obtained after oven heating when correlated to the microwave heating data showed the oryzanol content 13,371, 13,267 and 13,188 ppm after 1 day, 4 days and 5 days respectively which were closely correlated with the experimental value.

  9. Science at Home: Measuring a Thermophysical Property of Water with a Microwave Oven

    Science.gov (United States)

    Levine, Zachary H.

    2018-02-01

    An attempt to calibrate a conventional oven led to making a measurement of a thermophysical property of water using items found in the author's home. Specifically, the ratio of the energy required to heat water from the melting point to boiling to the energy required to completely boil away the water is found to be 5.7. This may be compared to the standard value of 5.5. The close agreement is not representative of the actual uncertainties in this simple experiment (Fig. 1). Heating water in a microwave oven can let a student apply the techniques of quantitative science based on questions generated by his or her scientific curiosity.

  10. PENGUKURAN KADAR AIR AGREGAT DAN BETON SEGAR DENGAN MENGGUNAKAN MICROWAVE OVEN

    Directory of Open Access Journals (Sweden)

    Handoko Sugiharto

    2000-01-01

    Full Text Available The conventional method of water content measurement of aggregate and fresh concrete need along time to perform. As an alternative the use of microwave oven is explored in this research. The microwave oven used has 900 watt power and equiped with a turn table. Nine (9 type of aggregate consist of five (5 type of fine aggregate and four (4 type of coarse aggregate with varions water absorbsion value, are unvestigated. The rater contents measured is then compared with the once obtained using conventional oven. Four (4 type of mix using aggegate with varions water absorbsion values. Water content used for the fresh concrete mix is 0.3, 0.5 and 0.7. The test results show that this method can beused to measure water content of fine and coarse aggregate regardless of the water absorbsion values of the aggregates. For fine aggregate nine (9 minutes drying time is needed to get 100% accuracy while for coarse aggregate 11 minutes with 96% accuracy. For fresh concrete using aggregate with less than 5% absorbsion value 18 minutes is neede to get 98% accuracy, while for aggregate with 40% absorbsion value 35 minutes is needed to get 80% accuracy. Abstract in Bahasa Indonesia : Pengukuran kadar air pada agregat dan beton segar dengan metode konvensional memerlukan waktu yang cukup lama, maka dilakukan penelitian penggunaan microwave oven sebagai metode alternatifnya. Microwave oven yang digunakan mempunyai daya 900 watt dan dilengkapi dengan piring putar. Dilakukan penelitian terhadap 9 tipe agregat (5 jenis agregat halus dan 4 jenis agregat kasar dengan berbagai nilai absorpsi. Sedangkan untuk beton segar dibuat 4 macam campuran dengan berbagai nilai absorpsi agregat. Faktor air-semen yang digunakan adalah 0.3, 0.5 dan 0.7. Hasil pengukuran kadar airnya dengan microwave oven dibandingkan terhadap oven standard. Hasil tes yang diperoleh menunjukkan bahwa metode ini dapat digunakan untuk mengukur kadar air agregat halus dan kasar dengan tidak tergantung pada

  11. Design of Controlled Release Non-erodible Polymeric Matrix Tablet Using Microwave Oven-assisted Sintering Technique.

    Science.gov (United States)

    Patel, Dm; Patel, Bk; Patel, Ha; Patel, Cn

    2011-07-01

    The objective of the present study was to evaluate the effect of sintering condition on matrix formation and subsequent drug release from polymer matrix tablet for controlled release. The present study highlights the use of a microwave oven for the sintering process in order to achieve more uniform heat distribution with reduction in time required for sintering. We could achieve effective sintering within 8 min which is very less compared to conventional hot air oven sintering. The tablets containing the drug (propranolol hydrochloride) and sintering polymer (eudragit S-100) were prepared and kept in a microwave oven at 540 watt, 720 watt and 900 watt power for different time periods for sintering. The sintered tablets were evaluated for various tablet characteristics including dissolution study. Tablets sintered at 900 watt power for 8 min gave better dissolution profile compared to others. We conclude that microwave oven sintering is better than conventional hot air oven sintering process in preparation of controlled release tablets.

  12. Digestion of Plastic Materials for the Determination of Toxic Metals with a Microwave Oven for Household Use

    National Research Council Canada - National Science Library

    SAKURAI, Hiroki; NORO, Junji; KAWASE, Akira; FUJINAMI, Masanori; OGUMA, Koichi

    2006-01-01

    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...

  13. Death in the "microwave oven": A form of execution by carbonization.

    Science.gov (United States)

    Durão, Carlos; Machado, Marcos P; Daruge Júnior, Eduardo

    2015-08-01

    Death in the "microwave oven" has nothing to do with microwaves energy. It is the jargon name given to a criminal form of execution by carbonization that has been adopted by drug dealers in Rio de Janeiro (Brazil). The goal is to torture and intimidate victims, in an attempt of corpse occultation and to make identification harder or impossible. This paper brings to attention of the forensic international community an unusual and very cruel form of execution as a way to document these situations. Copyright © 2015. Published by Elsevier Ireland Ltd.

  14. Simulation of electrical and thermal fields in a multimode microwave oven using software written in C++

    Science.gov (United States)

    Abrudean, C.

    2017-05-01

    Due to multiple reflexions on walls, the electromagnetic field in a multimode microwave oven is difficult to estimate analytically. This paper presents a C++ program that calculates the electromagnetic field in a resonating cavity with an absorbing payload, uses the result to calculate heating in the payload taking its properties into account and then repeats. This results in a simulation of microwave heating, including phenomena like thermal runaway. The program is multithreaded to make use of today’s common multiprocessor/multicore computers.

  15. Aquecimento em forno de microondas / desenvolvimento de alguns conceitos fundamentais Heating in microwave ovens/ developing of basic concepts

    Directory of Open Access Journals (Sweden)

    Ana Claudia R. N. Barboza

    2001-12-01

    Full Text Available The microwave oven became a common domestic equipment, due mainly to the short time spent to heat foods. One of the most interesting characteristics of the microwave oven is the selective heating. Different from the conventional oven, where the heating is not selective, the heating by microwave depends on the chemical nature of the matter. Many Students of Chemistry have no knowledge of the principles involved in this selective heating, in spite of the daily microwave oven use. The heating by microwave is feasible for chemistry courses. In discussions about the microwave absorption by the matter it is possible to explore chemical properties like: heat capacity, chemical bound, molecular structure, dipole moments, polarization and dielectric constant. This paper presents the basic principles involved in the microwave heating. It is proposed a simple and inexpensive experiment that could be developed in general chemistry courses, to illustrate the relationship between heating and the chemical properties of some solvents. Experiments to check the power of the microwave oven are also proposed.

  16. Use of microwave oven improves morphology and staining of cryostat sections.

    Science.gov (United States)

    Kennedy, A; Foulis, A K

    1989-01-01

    The quality of microscopic image of cryostat sections that had been subjected to microwave assisted fixation was compared with that resulting from conventional air drying of the sections. The role of microwaves in producing rapid special stains on cryostat sections was also assessed. Methods used permitted stains such as periodic acid Schiff, alcian blue, Gordon and Sweets's reticulin, Masson Fontana, Elastica, Prussian blue and Van Gieson to be performed within three minutes of cutting a cryostat section. The cytological detail of nuclei was much clearer using the microwave technique, allowing more accurate determination of cell type. The microwave oven seems to have major potential in improving the diagnostic accuracy of surgical frozen sections. Images Fig 1 Fig 2 Fig 3 Fig 4 Fig 5 PMID:2466053

  17. Fracture toughness of yttria-stabilized zirconia sintered in conventional and microwave ovens.

    Science.gov (United States)

    Marinis, Aristotelis; Aquilino, Steven A; Lund, Peter S; Gratton, David G; Stanford, Clark M; Diaz-Arnold, Ana M; Qian, Fang

    2013-03-01

    The fabrication of zirconium dioxide (ZrO2) dental prosthetic substructures requires an extended sintering process (8 to 10 hours) in a conventional oven. Microwave sintering is a shorter process (2 hours) than conventional sintering. The purpose of this study was to compare the fracture toughness of 3 mol % Y2O3-stabilized ZrO2 sintered in a conventional or microwave oven. Partially sintered ZrO2 specimens from 3 manufacturers, KaVo, Lava 3M, and Crystal HS were milled (KaVo Everest engine) and randomly divided into 2 groups: conventional sintering and microwave sintering (n=16 per group). The specimens were sintered according to the manufacturers' recommendations and stored in artificial saliva for 10 days. Fracture toughness was determined by using a 4-point bend test, and load to fracture was recorded. Mean fracture toughness for each material was calculated. A 2-way ANOVA followed by the Tukey HDS post hoc test was used to assess the significance of sintering and material effects on fracture toughness, including an interaction between the 2 factors (α=.05). The 2-way ANOVA suggested a significant main effect for ZrO2 manufacturer (P.05). The main effect of the sintering process (Conventional [5.30 MPa·m(1/2) ±1.00] or Microwave [5.36 MPa·m(1/2) ±0.92]) was not significant (P=.76), and there was no interaction between sintering and ZrO2 manufacturer (P=.91). Based on the results of this study, no statistically significant difference was observed in the fracture toughness of ZrO2 sintered in microwave or conventional ovens. Copyright © 2013 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

  18. Multiple tube structure for heating uniformity and efficiency optimization of microwave ovens

    Science.gov (United States)

    Zhou, Rong; Yang, Xiaoqing; Sun, Di; Jia, Guozhu

    2015-02-01

    Microwave heating is widely applied to microwave assisted chemical reactions in modified domestic microwave ovens, however, the potential issues (non-uniformity and low heating efficiency) still exist during the heating process. In this paper, a new heating model of multiple tube structure is proposed and the relevant simulations and experiments of heating water were performed based on the computational platform COMSOL Multi-physics software in order to achieve the better temperature uniformity and heating efficiency. Besides, the influence of the instability of microwave ovens on the heating performances of the optimal heating models was analyzed. The simulation results show that the heating uniformity and efficiency of water in optimal six tube structure increased by 7.1% and 68.5% (30 mL), 9.2% and 61% (60 mL) respectively compared with the optimal single tube structure. Moreover, the heating performances of the optimal heating models do not change obviously, while the working frequency and power change slightly. The simulation results are in good agreement with the experiment data.

  19. Improving heating uniformity of pathological tissue specimens inside a domestic microwave oven.

    Science.gov (United States)

    Hassan, Osama A; Kandil, Ahmed H; El Bialy, Ahmed M; Hassaballa, Iman A

    2013-01-01

    A 3D coupled electromagnetic thermal model was developed using COMSOL 4.0 to predict the electromagnetic field distribution and temperature profile in pathological tissue samples immersed in a reagent inside the oven cavity. The effect of the volume of reagent on the mean heating rate and heating uniformity within the tissue sample was investigated. Also, the effect of using a water load, as a method of temperature control, is emphasized. A well insulated K type thermocouple connected to a PC is used for model validation. Good agreement is found between experimental and simulated temperature profiles. Results show that as the volume of reagent increases, the mean heating rate decreases and temperature homogeneity increases. Also, it is possible to minimize overshooting temperature values inside the tissue sample and enhance tissue uniformity by about 27% using 100 ml of water load and 42.26% using 150 ml. Domestic microwave oven is a low cost economical tool that can speed up tissue processing steps. Achieving uniform heating inside the microwave oven is the key factor for improving workflow inside pathological labs and maintaining tissue quality and integrity.

  20. Exposure assessment of microwave ovens and impact on total exposure in WLANs.

    Science.gov (United States)

    Plets, David; Verloock, Leen; Van Den Bossche, Matthias; Tanghe, Emmeric; Joseph, Wout; Martens, Luc

    2016-02-01

    In situ exposure of electric fields of 11 microwave ovens is assessed in an occupational environment and in an office. Measurements as a function of distance without load and with a load of 275 ml of tap water were performed at distances of oven (without load), which is 2.5 and 1.1 times below the International Commission on Non-Ionizing Radiation Protection reference level for occupational exposure and general public exposure, respectively. For exposure at distances of >1 m, a model of the electric field in a realistic environment is proposed. In an office scenario, switching on a microwave oven increases the median field strength from 91 to 145 mV m(-1) (+91 %) in a traditional Wireless Local Area Network (WLAN) deployment and from 44 to 92 mV m(-1) (+109 %) in an exposure-optimised WLAN deployment. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Dry matter genotypes of Cynodon by microwave and conventional oven methods

    Directory of Open Access Journals (Sweden)

    Euclides Reuter de Oliveira

    2013-02-01

    Full Text Available The aimed of this work was to comparing the drying process in a microwave oven and forced air ventilation, as well as their effects on the chemical composition of different genotypes of the genus Cynodon (Tifton 85, Jiggs, Russell, Tifton 68 and Vaquero collected at different ages cutting (28, 48, 63 and 79 days. The experimental design was a randomized block in a split-plot design, with 4 replicates. There was no difference (P>0.05 between the methods analyzed on the chemical composition of the genotypes studied. Increasing age cutoff negatively influenced (P<0.05 the crude protein content of the different plant parts. A significant increase (P<0.05 of dry matter, neutral detergent fiber, acid detergent fiber and dry matter production was observed with increasing age cut. The use of the microwave oven is a quick and precise method obtain the dry matter content of the fodder showing efficiency similar to the method of drying in an oven with forced air circulation. The genotypes showed better chemical composition results when handled at age 28 days.

  2. Sensory quality and energy use for scrambled eggs and beef patties heated in institutional microwave and convection ovens

    Energy Technology Data Exchange (ETDEWEB)

    Cremer, M.L.

    1982-05-01

    Scrambled eggs (96 portions) and beef patties (96 portions) were heated in institutional microwave and convection ovens to determine energy use in heating and sensory quality of food. For both products, significantly (P < 0.01) more energy (BTU) was used for heating in the convection than in the microwave oven and respective amounts (BTU) were 28658.7 and 9385.7 for eggs; 31313.3 and 9365.0 for beef patties. All scores for sensory quality were significantly (P < 0.01) higher for eggs heated in the microwave than in the convection, but for beef patties, scores were higher for all characteristics and significantly (P < 0.01) higher for appearance, flavor, and general acceptability after heating in the convection rather than the microwave oven.

  3. Heat and mass transport during microwave heating of mashed potato in domestic oven--model development, validation, and sensitivity analysis.

    Science.gov (United States)

    Chen, Jiajia; Pitchai, Krishnamoorthy; Birla, Sohan; Negahban, Mehrdad; Jones, David; Subbiah, Jeyamkondan

    2014-10-01

    A 3-dimensional finite-element model coupling electromagnetics and heat and mass transfer was developed to understand the interactions between the microwaves and fresh mashed potato in a 500 mL tray. The model was validated by performing heating of mashed potato from 25 °C on a rotating turntable in a microwave oven, rated at 1200 W, for 3 min. The simulated spatial temperature profiles on the top and bottom layer of the mashed potato showed similar hot and cold spots when compared to the thermal images acquired by an infrared camera. Transient temperature profiles at 6 locations collected by fiber-optic sensors showed good agreement with predicted results, with the root mean square error ranging from 1.6 to 11.7 °C. The predicted total moisture loss matched well with the observed result. Several input parameters, such as the evaporation rate constant, the intrinsic permeability of water and gas, and the diffusion coefficient of water and gas, are not readily available for mashed potato, and they cannot be easily measured experimentally. Reported values for raw potato were used as baseline values. A sensitivity analysis of these input parameters on the temperature profiles and the total moisture loss was evaluated by changing the baseline values to their 10% and 1000%. The sensitivity analysis showed that the gas diffusion coefficient, intrinsic water permeability, and the evaporation rate constant greatly influenced the predicted temperature and total moisture loss, while the intrinsic gas permeability and the water diffusion coefficient had little influence. This model can be used by the food product developers to understand microwave heating of food products spatially and temporally. This tool will allow food product developers to design food package systems that would heat more uniformly in various microwave ovens. The sensitivity analysis of this study will help us determine the most significant parameters that need to be measured accurately for reliable

  4. Microwave oven heating for inactivation of Listeria monocytogenes on frankfurters before consumption.

    Science.gov (United States)

    Rodríguez-Marval, Mawill; Geornaras, Ifigenia; Kendall, Patricia A; Scanga, John A; Belk, Keith E; Sofos, John N

    2009-10-01

    Microwave oven heating was evaluated for inactivation of Listeria monocytogenes on inoculated and stored frankfurters. Frankfurters formulated without/with 1.5% potassium lactate and 0.1% sodium diacetate were inoculated with L. monocytogenes (1.9 +/- 0.2 log CFU/cm(2)), vacuum-packaged, and stored (4 degrees C) to simulate conditions prior to purchase by consumers. At storage days 18, 36, and 54, packages were opened and placed at 7 degrees C, simulating aerobic storage in a household refrigerator. At 0, 3, and 7 d of aerobic storage, 2 frankfurters were placed in a bowl with water (250 mL) and treated in a household microwave oven at high (1100 W) power for 30, 45, 60, or 75 s, or medium (550 W) power for 60 or 75 s. Frankfurters and the heating water were analyzed for total microbial counts and L. monocytogenes populations. Exposure to high power for 75 s reduced pathogen levels (0.7 +/- 0.0 to 1.0 +/- 0.1 log CFU/cm(2)) to below the detection limit ( 1.5 and 5.9 log CFU/cm(2) from control levels of 1.5 +/- 0.1 to 7.2 +/- 0.5 log CFU/cm(2). Depending on treatment and storage time, the water used to reheat the frankfurters had viable L. monocytogenes counts of microwave oven at high power for 75 s to inactivate up to 3.7 log CFU/cm(2) of L. monocytogenes contamination.

  5. Evaluation of microwave oven heating for prediction of drug-excipient compatibilities and accelerated stability studies

    DEFF Research Database (Denmark)

    Schou-Pedersen, Anne Marie V; Østergaard, Jesper; Cornett, Claus

    2015-01-01

    a design of experiments (DoE) approach in order to be able to rank excipients regarding reactivity: Study A: cetirizine with PEG 400, sorbitol, glycerol and propylene glycol. Study B: 6-aminocaproic acid with citrate, acetate, tartrate and gluconate. Study C: atenolol with citric, tartaric, malic, glutaric......, and sorbic acid. The model formulations were representative for oral solutions (co-solvents), parenteral solutions (buffer species) and solid dosage forms (organic acids applicable for solubility enhancement). The DoE studies showed overall that the same impurities were generated by microwave oven heating...

  6. Microwave Ovens

    Science.gov (United States)

    ... Manufacture Label on Radiation-Emitting Consumer Electronics Information Requirements For Cookbooks, and User and Service Manuals (PDF - 233KB) Guidance for Industry and FDA Staff - Addition of URLs to Electronic Product Labeling Other Resources FDA Consumer Update: 5 Tips for ...

  7. Comparison of childhood burns associated with use of microwave ovens and conventional stoves.

    Science.gov (United States)

    Powell, E C; Tanz, R R

    1993-02-01

    To identify the incidence, type, and severity of burns associated with microwave oven (MW) use and to compare MW-associated burns with those associated with use of conventional stoves, we conducted a review of a national data base. Data were obtained from the US Consumer Product Safety Commission Injury Information Clearinghouse for 1986 through 1990 concerning burn injuries to children (0 to 19 years). There were an estimated 5160 burns associated with MW use. The mean age was 7.6 years (median, 6 years); 25% of burns were to children younger than 36 months old. Fifty-eight percent involved females. Most MW burns were scalds (95%); 16% of these scalds were from exploding eggs or other food. No MW burn involved a body surface area greater than 25% and no patient required hospital admission. Microwave oven burns were compared with stove burns. There were an estimated 41198 stove-associated burns to children. The mean age was 5.8 years; the median was 3 years. Forty-five percent of burns were to children younger than 36 months old; 55% were to males. Most stove burns (74%) were thermal; 7% involved a body surface area greater than 25%. Five percent of children with stove burns required hospital admission. We conclude that (1) burns to children associated with MW use are less frequent and less severe than stove burns; (2) MW burns predominantly affect females; and (3) burn prevention efforts should emphasize the hazards of stoves, which vastly exceed those of MWs.

  8. Effect of different flours on quality of legume cakes to be baked in microwave-infrared combination oven and conventional oven.

    Science.gov (United States)

    Ozkahraman, Betul Canan; Sumnu, Gulum; Sahin, Serpil

    2016-03-01

    The objective of this study was to compare the quality of legume cakes baked in microwave-infrared combination (MW-IR) oven with conventional oven. Legume cake formulations were developed by replacing 10 % wheat flour by lentil, chickpea and pea flour. As a control, wheat flour containing cakes were used. Weight loss, specific volume, texture, color, gelatinization degree, macro and micro-structure of cakes were investigated. MW-IR baked cakes had higher specific volume, weight loss and crust color change and lower hardness values than conventionally baked cakes. Larger pores were observed in MW-IR baked cakes according to scanning electron microscope (SEM) images. Pea flour giving the hardest structure, lowest specific volume and gelatinization degree was determined to be the least acceptable legume flour. On the other hand, lentil and chickpea flour containing cakes had the softest structure and highest specific volume showing that lentil and chickpea flour can be used to produce functional cakes.

  9. DETERMINATION OF MOISTURE CONTENT OF BAGASSE OF JAGGERY UNIT USING MICROWAVE OVEN

    Directory of Open Access Journals (Sweden)

    S.I. ANWAR

    2010-12-01

    Full Text Available In jaggery making furnaces, sugarcane bagasse is used as fuel. Moisture content of bagasse affects its calorific value. So burning of bagasse at suitable level of moisture is essential from the viewpoint of furnace performance. Moisture content can also be used for indirect calculation of fibre content in sugarcane. Normally gravimetric method is used for moisture content determination, which is time consuming. Therefore, an attempt has been made to use microwave oven for drying of bagasse. It took about 20 to 25 minutes for the determination as compared to 8-10 hours in conventional hot air drying method and the results were comparable to the values obtained from hot air drying method.

  10. Comparison of Mathematical Equation and Neural Network Modeling for Drying Kinetic of Mendong in Microwave Oven

    Science.gov (United States)

    Maulidah, Rifa'atul; Purqon, Acep

    2016-08-01

    Mendong (Fimbristylis globulosa) has a potentially industrial application. We investigate a predictive model for heat and mass transfer in drying kinetics during drying a Mendong. We experimentally dry the Mendong by using a microwave oven. In this study, we analyze three mathematical equations and feed forward neural network (FNN) with back propagation to describe the drying behavior of Mendong. Our results show that the experimental data and the artificial neural network model has a good agreement and better than a mathematical equation approach. The best FNN for the prediction is 3-20-1-1 structure with Levenberg- Marquardt training function. This drying kinetics modeling is potentially applied to determine the optimal parameters during mendong drying and to estimate and control of drying process.

  11. Effect of Radiation Leakage of Microwave Oven on Rat Serum Testosterone at Pre and Post Pubertal Stage

    Directory of Open Access Journals (Sweden)

    Y Zare

    2008-01-01

    Full Text Available Introduction: Since discovery of high frequency waves, their biological effects have been in great attention. Increased male fertility problems proposed their possible relation to use of microwaves. Testes are of very active body tissues, which can be affected by these waves. Age of exposure may also be an important factor. Methods: This study was carried out to evaluated testosterone level in rats exposed to microwave radiation at pre and post puberty. For this study 18 adult (2 month old and 18 immature (1 month old male rats were selected and each group divided in two groups, control and test group. Test groups were exposed to 2450 MHZ microwaves produced by microwave oven (LG Brant, three times a day, 30 minute each time. Control groups were kept in laboratory at same temperature and light condition. After 60 days blood was collected by heart puncture and testosterone was measured in serum by RIA method. Mean testosterone levels were compared by T-test. Result: The results showed that in immature group testosterone has not changed significantly compare to control group; however in adult group this value was significantly decreased in test group in comparison with control (P<0.005. Conclusion: exposure to microwaves leakage of microwave oven decreased testosterone in adult male rats, which may be due to its direct effect on Leydig cells or indirectly through its effect on pituitary and hypothalamus.

  12. 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.

  13. Effect of Leaked Radiation from Microwave Oven on Bone Marrow of Male Rats in Pre and Post Pubertal Stage

    Directory of Open Access Journals (Sweden)

    G Jelodar

    2011-01-01

    Full Text Available Introduction: Increasing hematological diseases along with increased use of microwaves in different systems proposed possible correlation between them. Age of exposure to wave is also an important factor. This study was conducted to evaluate the effect of radiation leakaged from microwave oven on hemopoitic bone marrow cells at pre and post pubertal. Methods: Fourteen male mature (2 months old and 14 male immature rats(one month old were randomly divided in to four groups (control and test. Test groups were exposed, three times a day each time 30 min for 60 days, to microwaves produced by microwave oven. After sixty days, animals were sacrified and bone marrow samples were collected from femural bones. Percent of variose cells type and their morphology were evaluated in 500 cells of each smear. Results: exposure to microwave did not exert visible morphological alteration. In the immature experimental group significant decrease in percent of basophilic rubricyte, polychromatic rubricyte, meta rubricyte and all the erythroid cell types observed(P<0.05, whereas, meta myelocyte, notrophilic band, total myeloid cell types and prolifrative cells, other cell types and the myeloid/erythroid ratio significantly increased(P<0.05. In the mature group, however, a significant decrease in percent of meta rubricyte and myelocyte cells observed(P<0.05, although prolifrative cells and all other cell types were significantly increasing in this group. Conclusion: In conclusion, the radiation leaked from microwave oven in the experimental conditions had no effect on the morphology of hemopoitic bone marrow cells, though the number of these cells was altered especially in immature group.

  14. Zinc (Zn) Analysis in Milk by Microwave Oven Digestion and Differential Pulse Anodic Stripping Voltametry (DPASV) Technique

    OpenAIRE

    Mohineesh; Raina A.; Raj J.; Dogra T. D.

    2013-01-01

    Milk is very important component of human diet. The presence of over limit of heavy metal in milk may create significant health problems. In the present study, the direct determination of Zinc (Zn) heavy metal in milk samples of different brands was carried out by differential pulse anodic stripping Voltammetric technique at Hanging Mercury Drop Electrode (HMDE). Milk samples were processed by microwave oven digestion using HP/VHP Vessels and TFM Liners and nitric acid (HNO3).Determination of...

  15. Effect on orange juice of batch pasteurization in an improved pilot-scale microwave oven.

    Science.gov (United States)

    Cinquanta, L; Albanese, D; Cuccurullo, G; Di Matteo, M

    2010-01-01

    The effects on orange juice batch pasteurization in an improved pilot-scale microwave (MW) oven was evaluated by monitoring pectin methyl-esterase (PME) activity, color, carotenoid compounds and vitamin C content. Trials were performed on stirred orange juice heated at different temperatures (60, 70, 75, and 85 degrees C) during batch process. MW pilot plant allowed real-time temperature control of samples using proportional integrative derivative (PID) techniques based on the infrared thermography temperature read-out. The inactivation of heat sensitive fraction of PME, that verifies orange juice pasteurization, showed a z-value of 22.1 degrees C. Carotenoid content, responsible for sensorial and nutritional quality in fresh juices, decreased by about 13% after MW pasteurization at 70 degrees C for 1 min. Total of 7 carotenoid compounds were quantified during MW heating: zeaxanthin and beta-carotene content decreased by about 26%, while no differences (P < 0.05) were found for beta-cryptoxanthin in the same trial. A slight decrease in vitamin C content was monitored after MW heating. Results showed that MW heating with a fine temperature control could result in promising stabilization treatments.

  16. Microwave drying of granules containing a moisture-sensitive drug: a promising alternative to fluid bed and hot air oven drying.

    Science.gov (United States)

    Chee, Sze Nam; Johansen, Anne Lene; Gu, Li; Karlsen, Jan; Heng, Paul Wan Sia

    2005-07-01

    The impact of microwave drying and binders (copolyvidone and povidone) on the degradation of acetylsalicylic acid (ASA) and physical properties of granules were compared with conventional drying methods. Moist granules containing ASA were prepared using a high shear granulator and dried with hot air oven, fluid bed or microwave (static or dynamic bed) dryers. Percent ASA degradation, size and size distribution, friability and flow properties of the granules were determined. Granules dried with the dynamic bed microwave dryer showed the least amount of ASA degradation, followed by fluid bed dryer, static bed microwave oven and hot air oven. The use of microwave drying with a static granular bed adversely affected ASA degradation and drying capability. Dynamic bed microwave dryer had the highest drying capability followed by fluid bed, static bed microwave dryer and conventional hot air oven. The intensity of microwave did not affect ASA degradation, size distribution, friability and flow properties of the granules. Mixing/agitating of granules during drying affected the granular physical properties studied. Copolyvidone resulted in lower amount of granular residual moisture content and ASA degradation on storage than povidone, especially for static bed microwave drying. In conclusion, microwave drying technology has been shown to be a promising alternative for drying granules containing a moisture-sensitive drug.

  17. The effects of radiation leakage of microwave oven on body weight, cortisol, thyroid hormones and lipid profile in immature mice

    Directory of Open Access Journals (Sweden)

    Jelodar Ph.D. Gh

    2010-06-01

    Full Text Available "n Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi;} Background: High-frequency electromagnetic field (EMF is generated by different sources such as radar installations, radio and television transmitters, medical microwave diathermy device and domestic use of microwave ovens. Radiation leakage of microwave oven may be harmful for users. Kids who are residing near their mothers may expose to electromagnetic field. This study was carried out to evaluate the effect of radiation leakage of microwave oven on body weight, cortisol, thyroid hormones and plasma lipid profile."n"nMethods: Radiation leakage of microwave oven was measured by RF measuring instrument. For this study 20 immature (7±3 days old and 5±1 g weight mice were selected and randomly divided in two groups, control and test group. Test groups were exposed to 2450 MHZ microwaves produced by microwave oven three times a day, 30 minute each time. After 60 days, body weights of both groups were determined and the blood samples were collected by heart puncture. Serum cortisol and thyroid hormones levels were evaluated using RIA method."n"nResults: Radiation leakage from oven showed variations from 6.5 to 57.5 mW/cm2. Mean body weight in test group was 29.5% lower than control group. Serum cortisol, T3 and T4 level

  18. The Earth's mantle in a microwave oven: thermal convection driven by a heterogeneous distribution of heat sources

    Science.gov (United States)

    Fourel, Loïc; Limare, Angela; Jaupart, Claude; Surducan, Emanoil; Farnetani, Cinzia G.; Kaminski, Edouard C.; Neamtu, Camelia; Surducan, Vasile

    2017-08-01

    Convective motions in silicate planets are largely driven by internal heat sources and secular cooling. The exact amount and distribution of heat sources in the Earth are poorly constrained and the latter is likely to change with time due to mixing and to the deformation of boundaries that separate different reservoirs. To improve our understanding of planetary-scale convection in these conditions, we have designed a new laboratory setup allowing a large range of heat source distributions. We illustrate the potential of our new technique with a study of an initially stratified fluid involving two layers with different physical properties and internal heat production rates. A modified microwave oven is used to generate a uniform radiation propagating through the fluids. Experimental fluids are solutions of hydroxyethyl cellulose and salt in water, such that salt increases both the density and the volumetric heating rate. We determine temperature and composition fields in 3D with non-invasive techniques. Two fluorescent dyes are used to determine temperature. A Nd:YAG planar laser beam excites fluorescence, and an optical system, involving a beam splitter and a set of colour filters, captures the fluorescence intensity distribution on two separate spectral bands. The ratio between the two intensities provides an instantaneous determination of temperature with an uncertainty of 5% (typically 1K). We quantify mixing processes by precisely tracking the interfaces separating the two fluids. These novel techniques allow new insights on the generation, morphology and evolution of large-scale heterogeneities in the Earth's lower mantle.

  19. Evaluation and comparison of high-level microwave oven disinfection with chemical disinfection of dental gypsum casts.

    Science.gov (United States)

    Meghashri, K; Kumar, Prasanna; Prasad, D Krishna; Hegde, Rakshit

    2014-06-01

    The aim of this study was to evaluate and compare microwave disinfection with chemical disinfection of dental gypsum casts. A total of 120 casts were prepared from a silicone mold using Type III dental stone. Of the 120 casts, 60 casts were contaminated with 1 ml suspension of Staphylococcus aureus and 60 casts were contaminated with 1 ml suspension of Pseudomonas aeruginosa. Then, the casts were disinfected with microwave irradiation and chemical disinfection using the microwave oven and 0.5% sodium hypochlorite. Bacteriologic procedures were performed; the cfu/ml for each cast was calculated as a weighted mean. The results were analyzed using Kruskal-Wallis test and Mann-Whitney test. The untreated casts showed Brain heart infusion broth counts of 106 log cfu/ml compared to irradiated and chemically disinfected casts, in which 105 log reduction of cfu/ml was seen. These results satisfied the requirements of current infection control guidelines for the dental laboratory. The results obtained for chemical disinfection were in equivalence with microwave disinfection. Within the limitation of this in vitro study, it was found that microwave disinfection of casts for 5 min at 900 W gives high-level disinfection that complies with the current infection control guidelines for the dental laboratory and microwave disinfection method is an effective and validated method as chemical disinfection. How to cite the article: Meghashri K, Kumar P, Prasad DK, Hegde R. Evaluation and comparison of high-level microwave oven disinfection with chemical disinfection of dental gypsum casts. J Int Oral Health 2014;6(3):56-60 .

  20. 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.

  1. Antilisterial properties of marinades during refrigerated storage and microwave oven reheating against post-cooking inoculated chicken breast meat.

    Science.gov (United States)

    Fouladkhah, Aliyar; Geornaras, Ifigenia; Nychas, George-John; Sofos, John N

    2013-02-01

    This study evaluated growth of Listeria monocytogenes inoculated on cooked chicken meat with different marinades and survival of the pathogen as affected by microwave oven reheating. During aerobic storage at 7 °C, on days 0, 1, 2, 4, and 7, samples were reheated by microwave oven (1100 W) for 45 or 90 s and analyzed microbiologically. L. monocytogenes counts on nonmarinated (control) samples increased (P juice were not different (P ≥ 0.05; 6.9 ± 0.1 log CFU/g) from those of the control, whereas for samples treated with the remaining marinades, pathogen counts were 0.7 (soy sauce) to 2.0 (lemon juice) log CFU/g lower (P monocytogenes counts by 1.9 to 4.1 (45 s) and >2.4 to 5.0 (90 s) log CFU/g. With similar trends across different marinates, the high levels of L. monocytogenes survivors found after microwave reheating, especially after storage for more than 2 d, indicate that length of storage and reheating time need to be considered for safe consumption of leftover cooked chicken. © 2013 Institute of Food Technologists®

  2. A new sensor-based self-configurable bandstop filter for reducing the energy leakage in industrial microwave ovens

    Science.gov (United States)

    Clemente-Fernández, F. J.; Monzó-Cabrera, J.; Pedreño-Molina, J. L.; Lozano-Guerrero, A. J.; Fayos-Fernández, J.; Díaz-Morcillo, A.

    2012-06-01

    In this work a new sensor-based self-configurable waveguide bandstop filter that uses a combination of metallic irises and reconfigurable posts for reducing the energy leakage in industrial microwave ovens is presented and validated through a procedure fully based on measurements. Several optimization and reconfiguration alternatives of the moving posts such as genetic algorithms and parametric sweeps are assessed. Results show that good attenuation values can be obtained for all the analyzed scenarios. In particular, genetic algorithms are shown as the best search strategy. Design and optimization times are also reduced when using the proposed filter compared to computer simulations.

  3. Lactose and galactose content in cheese results in overestimation of moisture by vacuum oven and microwave methods.

    Science.gov (United States)

    Lee, H; Rankin, S A; Fonseca, L M; Milani, F X

    2014-05-01

    Moisture determination in cheese is a critical test for regulatory compliance, functionality, and economic reasons. Common methods for moisture determination in cheese rely upon the thermal volatilization of water from cheese and calculation of moisture content based on the resulting loss of mass. Residual sugars, such as lactose and galactose, are commonly present in cheeses at levels ranging from trace amounts to 5%. These sugars are capable of reacting with other compounds in cheese, especially under the thermal conditions required for moisture determination, to yield volatile reaction products. The hypothesis of this work is that residual sugars in cheese will be converted into volatile compounds over the course of moisture determination at a level sufficient to result in overestimated cheese moisture. A full-factorial statistical design was used to evaluate the effects of cheese type, sugar type, sugar level, method type, and all interactions. Cheddar and low-moisture, part-skim (LMPS) Mozzarella cheeses were prepared with 1, 3, and 5% added lactose or galactose, and subjected to either vacuum oven or microwave-based moisture determination methods. Browning index and colorimetry were measured to characterize the color and extent of browning. Volatile analyses were performed to provide chemical evidence of the reactions proposed. The presence of residual sugars altered moisture calculations as a function of cheese type, sugar type, sugar level, method type, and numerous interactions. At higher concentrations of residual sugar, the percentage moisture determinations were increased by values of up to 1.8. Measures of browning reactions, including browning index, colorimetry, and volatile profiles demonstrate that the proposed browning reactions played a causative role. This work establishes the need to consider cheese type, sugar type, sugar levels, and method type as a means of more accurately determining moisture levels. Copyright © 2014 American Dairy Science

  4. An Enhancing Effect of Gold Nanoparticles on the Lethal Action of 2450 MHz Electromagnetic Radiation in Microwave Oven.

    Science.gov (United States)

    Mollazadeh-Moghaddam, Kamyar; Moradi, Bardia Varasteh; Dolatabadi-Bazaz, Reza; Shakibae, Mojtaba; Shahverdi, Ahmad Reza

    2011-10-01

    Today, there is an increasing interest in the use of metal nanoparticles in health sciences. Amongst all nanoparticles, the gold nanoparticles have been known to kill the cancer cells under hyperthermic condition by near-infrared frequency electromagnetic waves. On the other hand, although there are different physiochemical methods for disinfection of microbial pollution, however applications of irradiated gold nanoparticles against microorganisms have not yet been investigated. In this study, gold nanoparticles were prepared using D-glucose and characterized (particle size electromagnetic radiation generated at a microwave oven operated at low power (100 W), was investigated by time-kill course assay against Staphylococcus aureus (S.aureus) ATCC 29737. The results showed that application of gold nanoparticles can enhance the lethal effect of low power microwave in a very short exposure time (5 s).

  5. Optimization of formulation of soy-cakes baked in infrared-microwave combination oven by response surface methodology.

    Science.gov (United States)

    Şakıyan, Özge

    2015-05-01

    The aim of present work is to optimize the formulation of a functional cake (soy-cake) to be baked in infrared-microwave combination oven. For this optimization process response surface methodology was utilized. It was also aimed to optimize the processing conditions of the combination baking. The independent variables were the baking time (8, 9, 10 min), the soy flour concentration (30, 40, 50 %) and the DATEM (diacetyltartaric acid esters of monoglycerides) concentration (0.4, 0.6 and 0.8 %). The quality parameters that were examined in the study were specific volume, weight loss, total color change and firmness of the cake samples. The results were analyzed by multiple regression; and the significant linear, quadratic, and interaction terms were used in the second order mathematical model. The optimum baking time, soy-flour concentration and DATEM concentration were found as 9.5 min, 30 and 0.72 %, respectively. The corresponding responses of the optimum points were almost comparable with those of conventionally baked soy-cakes. So it may be declared that it is possible to produce high quality soy cakes in a very short time by using infrared-microwave combination oven.

  6. Science at Home: Measuring a Thermophysical Property of Water with a Microwave Oven

    Science.gov (United States)

    Levine, Zachary H.

    2018-01-01

    An attempt to calibrate a conventional oven led to making a measurement of a thermophysical property of water using items found in the author's home. Specifically, the ratio of the energy required to heat water from the melting point to boiling to the energy required to completely boil away the water is found to be 5.7. This may be compared to the…

  7. Antioxidant activity in barley (Hordeum Vulgare L.) grains roasted in a microwave oven under conditions optimized using response surface methodology.

    Science.gov (United States)

    Omwamba, Mary; Hu, Qiuhui

    2010-01-01

    Microwave processing and cooking of foods is a recent development that is gaining momentum in household as well as large-scale food applications. Barley contains phenol compounds which possess antioxidant activity. In this study the microwave oven roasting condition was optimized to obtain grains with high antioxidant activity measured as the ability to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical. Antioxidant activity of grains roasted under optimum conditions was assessed based on DPPH radical scavenging activity, reducing power and inhibition of oxidation in linoleic acid system. The optimum condition for obtaining roasted barley with high antioxidant activity (90.5% DPPH inhibition) was found to be at 600 W microwave power, 8.5 min roasting time, and 61.5 g or 2 layers of grains. The roasting condition influenced antioxidant activity both individually and interactively. Statistical analysis showed that the model was significant (P < 0.0001). The acetone extract had significantly high inhibition of lipid peroxidation and DPPH radical scavenging activity compared to the aqueous extract and alpha-tocopherol. The reducing power of acetone extracts was not significantly different from alpha-tocopherol. The acetone extract had twice the amount of phenol content compared to the aqueous extract indicating its high extraction efficiency. GC-MS analysis revealed the presence of phenol acids, amino phenols, and quinones. The aqueous extract did not contain 3,4-dihydroxybenzaldehyde and 4-hydroxycinnamic acid which are phenol compounds reported to contribute to antioxidant activity in barley grain.

  8. Preparation and characterization of a homemade Josephson junction prepared from a thin film sintered in a domestic microwave oven

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, Gustavo Quereza; Moreto, Jeferson Aparecido [Instituto Federal de Educacao, Ciencia e Tecnologia Goiano (IFGO), Rio Verde, GO (Brazil); Zadorosny, Rafael; Silveira, Joao Borsil; Carvalho, Claudio Luiz [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Ilha Solteira, SP (Brazil); Cena, Cicero Rafael, E-mail: gustavoquereza@yahoo.com.br [Instituto Federal de Educacao, Ciencia e Tecnologia de Sao Paulo (IFSP), Birigui, SP (Brazil)

    2016-03-15

    A homemade Josephson junction was successfully obtained using a superconductor thin film of the BSCCO system. The film was deposited on a lanthanum aluminate, produced from a commercial powder with a nominal composition Bi{sub 1.8}Pb{sub 0.4}Sr{sub 2}CaCu{sub 2}O{sub x}, was thermally treated by a domestic microwave oven. The XRD analysis of the film indicated the coexistence of Bi-2212 and Bi-2223 phases and SEM images revealed that a typical superconductor plate-like morphology was formed. From the electrical characterization, performed using DC four probes technique, it was observed an onset superconducting transition temperature measured around 81K. At the current-voltage characteristics curve, a step of electric current at zero-voltage could be observed, an indicative that the tunneling Josephson occurred. (author)

  9. Endo-β-N-acetylglucosaminidase H de-N-glycosylation in a domestic microwave oven: application to biomarker discovery.

    Science.gov (United States)

    Frisch, Elena; Schwedler, Christian; Kaup, Matthias; Iona Braicu, Elena; Gröne, Jörn; Lauscher, Johannes C; Sehouli, Jalid; Zimmermann, Matthias; Tauber, Rudolf; Berger, Markus; Blanchard, Véronique

    2013-02-01

    Sample preparation is the rate-limiting step in glycan analysis workflows. Among all of the steps, enzymatic digestions, which are usually performed overnight, are the most time-consuming. In the current study, we report an economical and fast preparation of N-glycans from serum, including microwave-assisted enzymatic digestion in the absence of denaturing chemicals and solvents during the release. To this end, we used a household microwave oven to accelerate both pronase and endo-β-N-acetylglucosaminidase H (Endo H) digestions. Purification was then performed using self-made SP20SS and carbon tips. We were able to prepare samples in 55 min instead of 21 h. Finally, the method was applied in the context of oncological biomarker discovery exemplarily to ovarian and colon cancer. We observed a significant downregulation of sialylated hybrid structures in ovarian cancer samples using capillary electrophoresis-laser-induced fluorescence (CE-LIF). Furthermore, sepsis, a systemic inflammatory response syndrome, was also included in the study to understand whether the changes observed in ovarian cancer patients were due to the cancer itself or to the inflammation that usually accompanies its development. Because sialylated hybrid structures were upregulated in sepsis samples, the downregulation of these structures in ovarian cancer is specific to the cancer itself and, therefore, could be used as a biomarker. Copyright © 2012 Elsevier Inc. All rights reserved.

  10. Determination of water content in clay and organic soil using microwave oven

    Science.gov (United States)

    Kramarenko, V. V.; Nikitenkov, A. N.; Matveenko, I. A.; Molokov, V. Yu; Vasilenko, Ye S.

    2016-09-01

    The article deals with the techniques of soil water content determination using microwave radiation. Its practical application would allow solving the problems of resource efficiency in geotechnical survey due to reduction of energy and resource intensity of laboratory analysis as well as its acceleration by means of decreasing labour intensity and, as a result, cost reduction. The article presents a detail analysis of approaches to soil water content determination and soil drying, considers its features and application. The study in soil of different composition, typical for Western Siberia including organic and organic-mineral ones, is a peculiarity of the given article, which makes it rather topical. The article compares and analyzes the results of the investigation into soil water content, which are obtained via conventional techniques and the original one developed by the authors, consisting in microwave drying. The authors also give recommendation on microwave technique application to dry soil.

  11. Simulation of microwave heating of a composite part in an oven cavity

    Science.gov (United States)

    Tertrais, Hermine; Ibanez, Ruben; Barasinski, Anaïs; Ghnatios, Chady; Chinesta, Francisco

    2017-10-01

    Microwave (MW) technology relies on volumetric heating. Thermal energy is transferred to the material that can absorb it at specific frequencies. In this paper, a coupled thermic and electromagnetic model is proposed in order to simulate the emerging process of microwave heating for composite materials. Solving the problem in a laminated composite material requires a high degree of discretization in the thickness direction which is made possible by introducing the in-plane-out-of-plane decomposition approach using the Proper Generalized Decomposition (PGD).

  12. SOLVENT-FREE PREPARATION OF IONIC LIQUIDS USING A HOUSEHOLD MICROWAVE OVEN

    Science.gov (United States)

    An efficient solventless protocol for the preparation of a wide variety of ionic liquids is described which requires a simple exposure of admixed 1-methylimidazole and alkyl halides to microwave irradiation in open glass containers. The details of this clean process using a commo...

  13. Strength properties of preceramic brazed joints of a gold-palladium alloy with a microwave-assisted oven and gas/oxygen torch technique.

    Science.gov (United States)

    Kim, Hyeongil; Prasad, Soni; Dunford, Robert; Monaco, Edward A

    2014-09-01

    The effect of microwave brazing on the strength properties of dental casting alloys is not yet known. The purpose of this study was to compare the strength properties of preceramic brazed joints obtained by using a microwave oven and a conventional torch flame for a high noble alloy (Au-Pd). A total of 18 tensile bars made of an Au-Pd ceramic alloy were fabricated. Six specimens were cut and joined with a high-fusing preceramic solder in a specially designed microwave oven, and 6 specimens were joined with a conventional natural gas/oxygen torch. The remaining 6 uncut specimens were tested as a control. All the specimens were subjected to testing with a universal testing machine. A 1-way ANOVA was performed for each strength property tested. The tensile strength of the uncut group was the highest (745 ±19 MPa), followed by the microwave group (420 ±68 MPa) and the conventional torch group (348 ±103 MPa) (Pmicrowave group and gas torch group. The tensile strength of the microwave group exceeded ANSI/ADA Standard No. 88, Dental Brazing Alloys (a joint standard of the American National Standards Institute and the American Dental Association). The microwave heating preceramic solder method demonstrated the excellent tensile strength of an Au-Pd alloy and may be an alternative way of joining alloys when a torch flame is contraindicated. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  14. Microwave oven-based technique for immunofluorescent staining of paraffin-embedded tissues.

    Science.gov (United States)

    Long, Delwin J; Buggs, Colleen

    2008-02-01

    Immunohistochemical analysis of formalin-fixed paraffin-embedded tissues can be challenging due to potential modifications of protein structure by exposure to formalin. Heat-induced antigen retrieval techniques can reverse reactions between formalin and proteins that block antibody recognition. Interactions between antibodies and antigens are further enhanced by microwave irradiation, which has simplified immunohistochemical staining protocols. In this report, we modify a technique for antigen retrieval and immunofluorescent staining of formalin-fixed paraffin-embedded tissues by showing that it works well with several antibodies and buffers. This microwave-assisted method for antigen retrieval and immunofluorescent staining eliminates the need for blocking reagents and extended washes, which greatly simplifies the protocol allowing one to complete the analysis in less than 3 h.

  15. Oven, microwave, and combination roasting of peanuts: comparison of inactivation of salmonella surrogate Enterococcus faecium, color, volatiles, flavor, and lipid oxidation.

    Science.gov (United States)

    Smith, Alicia L; Perry, Jennifer J; Marshall, Julie A; Yousef, Ahmed E; Barringer, Sheryl A

    2014-08-01

    Peanut safety and quality were evaluated for different roasting technologies. Shelled raw peanuts were roasted using an oven at 163 to 204 °C, microwave, or oven and microwave combinations. The lethal effect of these treatments was investigated on peanuts inoculated with the Salmonella surrogate, Enterococcus faecium and stored at room temperature for 1 h, 24 h, or 7 d before roasting. Roasted peanut color, odor activity values (OAVs), descriptive sensory panel analysis, free fatty acid, and peroxide values were determined. Color and OAVs were also analyzed on 2 commercial peanut butters. OAVs were calculated using volatile levels quantified with selected ion flow tube mass spectrometry and known odor thresholds. All treatments resulted in a minimum of 3 log reduction of inoculated bacterial population. Resistance to the process was not influenced by storage of inoculated peanuts prior to treatment. Roasting by different methods produced equivalent, commercially ideal L* color. Based on the OAVs, treatments had similar volatiles important to flavor compared to the commercial samples. Descriptive sensory analysis showed no significant difference between the roasting treatments for most of the sensory attributes. Lipid oxidation was not significantly different between the roasting methods, displaying no evidence that roasting time or temperature affected lipid oxidation, when ideal color was produced. These results suggest that oven, microwave, or combination roasting should be sufficient to mitigate the threat of Salmonella contamination and produce similar color, OAVs, sensory attributes, and lipid oxidation results. © 2014 Institute of Food Technologists®

  16. Drying behaviour, effective diffusivity and energy of activation of olive leaves dried by microwave, vacuum and oven drying methods

    Science.gov (United States)

    Elhussein, Elaf Abdelillah Ali; Şahin, Selin

    2018-01-01

    Drying is the crucial food processing for bioactive components from plant materials before strating extraction in addition to preservation of raw plant materials during storage period. Olive leaves were dried by various methods such as microwave drying (MD), oven drying (OD) and vacuum drying (VD) at several temperature values in the present study. Mathematical models allow to develop, design and control the processes. 14 emprical equations were used to estimate the drying behaviour and the time required for drying. Convenience of the models were evaluated according to the correlation coefficient (R 2 ), varience (S 2 ) and root mean square deviation (D RMS ). On the other hand, the effective diffusion coefficient and energy for activation were also calculated. Effects of the drying methods on the total phenolic (TPC), flavonoid (TFC) and oleuropein contents and free radical scavenging activity (FRSA) of the olive leaves were also investigated to take into considiration the quality of the dried product. MD has proved to be the fastest drying method having the highest effective diffusivity and the lowest activation energy with a more qualitive product.

  17. Preparation of Ru Nanoparticles Supported on Al2O3 by Using Conventional Microwave Oven: Effect of Irradiation Power

    Science.gov (United States)

    Rini, Ari Sulistyo; Radiman, Shahidan; Yarmo, Mohd. Ambar

    2011-12-01

    Ru nanoparticles supported Al2O3 with uniform particle size have been synthesized by using conventional microwave oven in three different powers. RuCl3.nH2O, ethylene glycol, polyvinyl pyrolidone (PVP) were used as metal precursor, solvent and stabilizing agent, respectively. Beside irradiation power, effect of PVP and preparation route were also studied in this paper. The samples were characterized by UV-Vis, XRD, Small Angle X-Ray Scattering (SAXS), and TEM. The XRD pattern of Ru/Al2O3 catalysts did not show noticeable difference among each other. The powders were then analyzed further by SAXS technique. TEM image confirmed the nanosized (about 2 nm in average) of colloidal and supported ruthenium that obtained in all irradiation power. Ruthenium nanoparticles were also uniformly distributed over the support. The surface fractal distribution of ruthenium nanoparticles was examined by using SAXS. The irradiation power and the addition of PVP are strongly correlated with the surface fractal distribution of the nanoparticle.

  18. Zinc (Zn Analysis in Milk by Microwave Oven Digestion and Differential Pulse Anodic Stripping Voltametry (DPASV Technique

    Directory of Open Access Journals (Sweden)

    Mohineesh

    2013-04-01

    Full Text Available Milk is very important component of human diet. The presence of over limit of heavy metal in milk may create significant health problems. In the present study, the direct determination of Zinc (Zn heavy metal in milk samples of different brands was carried out by differential pulse anodic stripping Voltammetric technique at Hanging Mercury Drop Electrode (HMDE. Milk samples were processed by microwave oven digestion using HP/VHP Vessels and TFM Liners and nitric acid (HNO3.Determination of Zn was made in acetate buffer (pH 4.6 with a sweep rate (scan rate of 59.5 mV/s and pulse amplitude 50mV by HMDE by standard addition method. The solution was stirred during pre-electrolysis at -1150mV (vs. Ag/AgCl for 90 seconds and the potential was scanned from -1150V to +100V (vs. Ag/AgCl. The zinc ions were deposited by reduction at -1150 mV on HMDE. The stripping current arising from the oxidation of metal was correlated with the concentration the metal in the sample. .As a result the minimum level of Zn observed in the milk sample of different brands was determined as 2.28 mgL−1.

  19. Mantle Convection in a Microwave Oven: New Perspectives for the Internally Heated Convection

    Science.gov (United States)

    Limare, A.; Fourel, L.; Surducan, E.; Neamtu, C.; Surducan, V.; Vilella, K.; Farnetani, C. G.; Kaminski, E. C.; Jaupart, C. P.

    2015-12-01

    The thermal evolution of silicate planets is primarily controlled by the balance between internal heating - due to radioactive decay - and heat transport by mantle convection. In the Earth, the problem is particularly complex due to the heterogeneous distribution of heat sources in the mantle and the non-linear coupling between this distribution and convective mixing. To investigate the behaviour of such systems, we have developed a new technology based on microwave absorption to study internally-heated convection in the laboratory. This prototype offers the ability to reach the high Rayleigh-Roberts and Prandtl numbers that are relevant for planetary convection. Our experimental results obtained for a uniform distribution of heat sources were compared to numerical calculations reproducing exactly experimental conditions (3D Cartesian geometry and temperature-dependent physical properties), thereby providing the first cross validation of experimental and numerical studies of convection in internally-heated systems. We find that the thermal boundary layer thickness and interior temperature scale with RaH-1/4, where RaH is the Rayleigh-Roberts number, as theoretically predicted by scaling arguments on the dissipation of kinetic energy. Our microwave-based method offers new perspectives for the study of internally-heated convection in heterogeneous systems which have been out of experimental reach until now. We are able to selectively heat specific regions in the convecting layer, through the careful control of the absorption properties of different miscible fluids. This is analogous to convection in the presence of chemical reservoirs with different concentration of long-lived radioactive isotopes. We shall show results for two different cases: the stability of continental lithosphere over a convective fluid and the evolution of a hidden enriched reservoir in the lowermost mantle.

  20. "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.

  1. Adaptação de forno de microondas doméstico para realização de reações de transesterificação sob refluxo e catálise por argilas Adapting a domestic microwave oven transesterification reactions for under reflux and clay catalysis

    Directory of Open Access Journals (Sweden)

    Fernando de C. da Silva

    2006-04-01

    Full Text Available The microwave oven became an important source of heating for many laboratory procedures including accelerating organic reactions. Reactions that require long reflux times can sometimes be carried out in a few hours or minutes in a conventional microwave oven. However, longer reflux times can be troublesome since domestic microwave ovens are not prepared for these harsh conditions. This technical note presents our finding on heterogeneous catalysis transesterification reactions between b-keto-esters and carbohydrate derivatives under heating or microwave irradiation using an adapted domestic microwave oven.

  2. Technical support document: Energy efficiency standards for consumer products: Room air conditioners, water heaters, direct heating equipment, mobile home furnaces, kitchen ranges and ovens, pool heaters, fluorescent lamp ballasts and television sets. Volume 1, Methodology

    Energy Technology Data Exchange (ETDEWEB)

    1993-11-01

    The Energy Policy and Conservation Act (P.L. 94-163), as amended, establishes energy conservation standards for 12 of the 13 types of consumer products specifically covered by the Act. The legislation requires the Department of Energy (DOE) to consider new or amended standards for these and other types of products at specified times. DOE is currently considering amending standards for seven types of products: water heaters, direct heating equipment, mobile home furnaces, pool heaters, room air conditioners, kitchen ranges and ovens (including microwave ovens), and fluorescent light ballasts and is considering establishing standards for television sets. This Technical Support Document presents the methodology, data, and results from the analysis of the energy and economic impacts of the proposed standards. This volume presents a general description of the analytic approach, including the structure of the major models.

  3. Linear dimensional change, compressive strength and detail reproduction in type IV dental stone dried at room temperature and in a microwave oven.

    Science.gov (United States)

    Silva, Marcos Aurélio Bomfim da; Vitti, Rafael Pino; Consani, Simonides; Sinhoreti, Mário Alexandre Coelho; Mesquita, Marcelo Ferraz; Consani, Rafael Leonardo Xediek

    2012-01-01

    The type IV dental stone is widely used for the fabrication of dyes and master casts for fixed and removable partial prostheses. It is typically normal to wait at least 24 hours for the casts to dry prior to beginning the laboratory procedures. The waiting time has been shown to be greatly reduced by using microwave drying. This study evaluated the influence of drying techniques at room temperature and microwave oven on the linear dimensional change, compressive strength and detail reproduction in type IV dental stones. Three type IV dental stone brands were selected; elite Rock, Shera Premium and Durone IV. Two different drying protocols were tested in 4 groups (n=10); G-room temperature (25±4 ºC) dried for 2 hours; G2--room temperature dried for 24 hours; G3-room temperature dried for 7 days and G4--microwave oven dried at 800 W for 5 minutes and after 2 hours at room temperature. After drying, the samples were assayed for dimensional charges. The sample surface was submitted to the ImageTool 3.0 software for compressive strength in a universal testing machine with a cell load of 50 KN at a crosshead speed of 0.5 mm/minutes and the detail reproduction was analyzed with a stereomicroscope at 25x magnification. The statistical analysis of the linear dimensional change and compressive strength data were conducted by the ANOVA test followed by the Tukey test (pmicrowave oven drying showed a linear dimensional change similar to after room temperature drying for 24 hours and 7 days. The compressive strength of the stone dried in the microwave oven was similar to those dried at room temperature for 24 hours, with the exception of Shera Premium, which had similar results for microwave and room temperature drying for 7 days. For the microwave drying method the detail reproduction levels for samples dried at room temperature for 24 hours and 7 days were similar, except for the Durone IV.

  4. Absence of genotoxic activity from milk and water boiled in microwave oven in somatic cells from Drosophila melanogaster; Ausencia da atividade genotoxica do leite e agua, fervidos com microondas, em celulas somaticas de Drosophila melanogaster

    Energy Technology Data Exchange (ETDEWEB)

    Dias, Cristina das Dores. E-mail: crisddias@yahoo.com.br

    2003-07-01

    This paper reports an experiment for evaluation of the possible genotoxic effects of food prepared in a microwave oven, through the mutation test and somatic recombination, in wings of Drosophila melanogaster. Two crossing have been performed: a standard cross-ST and a high bioactivation cross - HB resulting in marked trans -heterozygote descendents (MH) and balanced heterozygotes (BH). The 72 hours larvas were fed with water and milk boiled both in the microwave oven and in the traditional way. The MH individual wings were analyzed, where the spots can be induced either by mutation or mitotic recombination. The experiment presented negative results related to the genotoxic effects of the water and milk boiled using the microwave oven, in MH descendents of both crossing. Therefore, under these experimental conditions, genotoxic activity were not presented by milk and water boiled in the microwave oven. However, an extensive study using different techniques is necessary to investigate the action of the food prepared in the microwave oven on the genetic material.

  5. HIGH-TEMPERATURE STERILIZATION OF TINNED COMPOTE FROM PEARS IN THE STREAM OF HEATED AIR WITH PRELIMINARY HEATING OF FRUITS IN EMP OF THE MICROWAVE OVEN

    Directory of Open Access Journals (Sweden)

    M. M. Akhmedova

    2014-01-01

    Full Text Available In work results of researches on improvement of technological process of production of tinned compote from pears with use of EMP microwave oven and high-temperature sterilization are presented.On the basis of the conducted pilot researches and with use of mathematical planning the approximation equation for determination of reference temperature of a product in bank before sterilization (T, °C, depending on three factors is received: container volume (V, k, microwave heating capacities (Р, kW and processing durations (t, c:New modes of high-temperature sterilization of compote from pears in various container are developed and offered.

  6. Evaluation of heating conditions of Ni-Zn ferrite obtained by combustion in a microwave oven; Avaliacao das condicoes de aquecimento de ferritas de Ni-Zn obtidas por reacao de combustao em forno microondas

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Rafaela L.P.; Diniz, Veronica Cristhina S.; Vieira, Debora A.; Costa, Ana Cristina F.M., E-mail: raffitasantos8@hotmail.com [Universidade Federal de Campina Grande (UFCG), Campina Grande, PB (Brazil). Departamento de Engenharia de Materiais; Kiminam, R.H.G.A. [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Departamento de Engenharia de Materiais

    2011-07-01

    This paper aims the synthesis by combustion reaction using microwave energy as heating source to obtain ferrite powders of Ni-Zn and its structural, morphological characterization. The influence of power and exposure time in the microwave oven was also investigated. The powders were prepared according to the theory of propellants and explosives using a vitreous silica crucible and urea as fuel. The powders were characterized by: XRD, BET and SEM. The resulted of XRD show only the formation of inverse spinel phase of Ni- Zn ferrite in all samples. The exposure time and power of microwave oven slightly altered the final characteristics of the powders. However, increasing the exposure time was more prominent than the increase of microwave power in both structural and morphological parameters. (author)

  7. Dielectric characterization of materials at microwave frequency range

    Directory of Open Access Journals (Sweden)

    J. de los Santos

    2003-01-01

    Full Text Available In this study a coaxial line was used to connect a microwave-frequency Network Analyzer and a base moving sample holder for dielectric characterization of ferroelectric materials in the microwave range. The main innovation of the technique is the introduction of a special sample holder that eliminates the air gap effect by pressing sample using a fine pressure system control. The device was preliminary tested with alumina (Al2O3 ceramics and validated up to 2 GHz. Dielectric measurements of lanthanum and manganese modified lead titanate (PLTM ceramics were carried out in order to evaluate the technique for a high permittivity material in the microwave range. Results showed that such method is very useful for materials with high dielectric permittivities, which is generally a limiting factor of other techniques in the frequency range from 50 MHz to 2 GHz.

  8. Effects of thermal treatments during cooking, microwave oven and boiling, on the unconjugated microcystin concentration in muscle of fish (Oreochromis niloticus).

    Science.gov (United States)

    Guzmán-Guillén, Remedios; Prieto, Ana I; Moreno, Isabel; Soria, Ma Eugenia; Cameán, Ana M

    2011-09-01

    Understanding the factors that contribute to the risk from fish consumption is a relevant public health concern due to potential adverse effects of cyanobacterial toxins. The aim of this work was to study the influence of two usual cooking practices, microwave oven and boiling, on the microcystin (MCs) concentration in fish muscle (Tilapia, Oreochromis niloticus) spiked with a stock solution (500 μL) containing a mixture of three toxins (MC-LR, MC-RR, and MC-YR) (1.5 μg/mL of each toxin). Two different variables were investigated: time of cooking in the microwaves treatment (1 or 5 min), and way of boiling, "boiled muscle" or "continuously heated muscle". All samples were then lyophilized and MCs were extracted and purified (Oasis HLB cartridge) and quantified by HPLC-MS. Furthermore, the waters in which the samples boiled were also analyzed after their purification. The results suggest a reduction on MC-LR (36%) and MC-YR (24.6%) in samples cooked in the microwave for 5 min. Major changes were found when the fish was cooked by the continuous boiling, with a decrease of 45.0% (MC-RR), 56.4% (MC-YR) and 59.3% (MC-LR). More studies are necessary to elucidate the mechanisms involved when aquatic food is submitted to usual cooking practices. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. Pedagogical Comparison of Five Reactions Performed under Microwave Heating in Multi-Mode versus Mono-Mode Ovens: Diels-Alder Cycloaddition, Wittig Salt Formation, E2 Dehydrohalogenation to Form an Alkyne, Williamson Ether Synthesis, and Fischer Esterification

    Science.gov (United States)

    Baar, Marsha R.; Gammerdinger, William; Leap, Jennifer; Morales, Erin; Shikora, Jonathan; Weber, Michael H.

    2014-01-01

    Five reactions were rate-accelerated relative to the standard reflux workup in both multi-mode and mono-mode microwave ovens, and the results were compared to determine whether the sequential processing of a mono-mode unit could provide for better lab logistics and pedagogy. Conditions were optimized so that yields matched in both types of…

  10. The use of domestic microwave oven in experimental classes of organic chemistry: salicylaldehyde nitration; O uso de aparelhos de micro-ondas domesticos em aulas experimentais de quimica organica: nitracao de salicilaldeido

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, Eurides Francisco; Santos, Ana Paula Bernardo dos; Bastos, Renato Saldanha; Pinto, Angelo C., E-mail: apcanela@yahoo.com.b [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Quimica. Dept. de Quimica Organica; Kuemmerle, Arthur Eugen [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Fac. de Farmacia. Dept. de Farmacos; Coelho, Roberto Rodrigues [Centro de Tecnologia Mineral (CETEM), Rio de Janeiro, RJ (Brazil)

    2010-07-01

    The use of microwave in chemistry has known benefits over conventional heating methods, e.g. reduced reaction times, chemical yield improvement and the possibility if reducing or eliminating the use of organic solvents. We describe herein a procedure for the nitration of salicylaldehyde in water using a domestic microwave oven, which can be used as an experiment in the undergraduate chemistry laboratory. The experiment involves safe and rapid preparation and identification of the position isomers by thin layer chromatography and {sup 1}H NMR, or by their melting points. (author)

  11. Effect of microwave drying and oven drying on the water activity, color, phenolic compounds content and antioxidant activity of coconut husk (Cocos nucifera L.).

    Science.gov (United States)

    Valadez-Carmona, Lourdes; Cortez-García, Rosa María; Plazola-Jacinto, Carla Patricia; Necoechea-Mondragón, Hugo; Ortiz-Moreno, Alicia

    2016-09-01

    The coconut (Cocos nucifera L.) husk is basically composed by fiber and pith material and remained under-utilized. This is an important source of phenolic compounds that could be used as functional ingredients. The aim of this study was to determine the effect of: oven-drying (OD) and microwave drying (MD), on the water activity, color, phenolic compound content and antioxidant activity of coconut husk. The OD was performed at 60 °C for 12 h and MD was performed at 900 W for 10 min. The total phenolic content (TPC) in fresh coconut husk was 64.2 mg GAE/g dry wt and significant higher than observed after OD and MD of 35.8 and 45.5 mg GAE/g dry wt, respectively. Ten phenols were identified in fresh and dehydrated coconut husks. The husk MD showed an increase in the content of gallic, 4-hydroxybenzoic, ferulic and syringic acids and epicatechin compared with the fresh; while coconut husk OD and MD, showed a decrease in the content of vanillic acid, vanillin, catequin and kaempferol. The antioxidant activity decreased after both OD and MD. However, MD resulted in a better antioxidant activity in husk than OD. MD of husk resulted into better retention of preserved color, TPC and TFC than OD.

  12. Continuous flow through a microwave oven for the large-scale production of biodiesel from waste cooking oil.

    Science.gov (United States)

    Tangy, Alex; Pulidindi, Indra Neel; Perkas, Nina; Gedanken, Aharon

    2017-01-01

    This report presents a method for producing large quantities of biodiesel from waste cooking oil (WCO). Preliminary studies on optimization of the WCO transesterification process in a continuous-flow microwave reactor are carried out using commercial SrO as a catalyst. The SrO catalyst can be separated and reused for five reaction cycles without loss in activity. Challenges like mass flow and pressure drop constraints need to be surmounted. SrO nanoparticles deposited on millimeter-sized (3-6mm) silica beads (41wt% SrO/SiO2) are prepared and evaluated as a substitute for the SrO catalyst. A WCO conversion value to biodiesel as high as 99.2wt% was achieved with the reactor packed with 15g of 41wt% SrO/SiO2 catalyst in 8.2min with 820mL of feed. Excellent performance of the fixed-bed catalyst without loss in activity for a lifetime of 24.6min converting a feed of 2.46L to FAME was observed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Comparison of the optical properties of pre-colored dental monolithic zirconia ceramics sintered in a conventional furnace versus a microwave oven.

    Science.gov (United States)

    Kim, Hee-Kyung; Kim, Sung-Hun

    2017-10-01

    The purpose of this study was to compare the optical properties of pre-colored dental monolithic zirconia ceramics of various thicknesses sintered in a microwave and those in a conventional furnace. A2-shade of pre-colored monolithic zirconia ceramic specimens (22.0 mm × 22.0 mm) in 3 thickness groups of 0.5, 1.0, and 1.5 mm were divided into 2 subgroups according to the sintering methods (n=9): microwave and conventional sintering. A spectrophotometer was used to obtain CIELab color coordinates, and translucency parameters and CIEDE2000 color differences (ΔE00) were measured. The relative amount of monoclinic phase (Xm) was estimated with x-ray diffraction. The surface topography was analyzed by atomic force microscope and scanning electron microscope. Statistical analyses were conducted with two-way ANOVA (α=.05). There were small interaction effects on CIE L*, a*, and TP between sintering method and thickness (Pmicrowave sintering regardless of thickness. Color differences between two sintering methods ranged from 0.52 to 0.96 ΔE00 units. The Xm values ranged from 7.03% to 9.89% for conventional sintering, and from 7.31% to 9.17% for microwave sintering. The microwave-sintered specimen demonstrated a smoother surface and a more uniform grain structure compared to the conventionally-sintered specimen. With reduced processing time, microwave-sintered pre-colored dental monolithic zirconia ceramics can exhibit similar color perception and translucency to those by conventional sintering.

  14. Physical optics for oven-plate scattering prediction

    Science.gov (United States)

    Baldauf, J.; Lambert, K.

    1991-07-01

    An oven assembly design is described, which will be used to determine the effects of temperature on the electrical properties of materials which are used as coatings for metal plates. Experimentally, these plates will be heated to a very high temperature in the oven assembly, and measured using a microwave reflectance measurement system developed for the NASA Lewis Research Center, Near-Field Facility. One unknown in this measurement is the effect that the oven assembly will have on the reflectance properties of the plate. Since the oven will be much larger than the plate, the effect could potentially be significant as the size of the plate becomes smaller. Therefore, it is necessary to predict the effect of the oven on the measurement of the plate. A method for predicting the oven effect is described, and the theoretical oven effect is compared to experimental results of the oven material. The computer code which is used to predict the oven effect is also described.

  15. Oven controlled N++ [1 0 0] length-extensional mode silicon resonator with frequency stability of 1 ppm over industrial temperature range

    Science.gov (United States)

    You, Weilong; Pei, Binbin; Sun, Ke; Zhang, Lei; Yang, Heng; Li, Xinxin

    2017-10-01

    This paper presents an oven controlled N++ [1 0 0] length-extensional mode silicon resonator, with a lookup-table based control algorithm. The temperature coefficient of resonant frequency (TCF) of the N++ doped resonator is nonlinear, and there is a turnover temperature point at which the TCF is equal to zero. The resonator is maintained at the turnover point by Joule heating; this temperature is a little higher than the upper limit of the industrial temperature range. It is demonstrated that the control algorithm based on the thermoresistor on the substrate and the lookup table for heating voltage versus chip temperature is sufficiently accurate to achieve a frequency stability of  ±0.5 ppm over the industrial temperature range. Because only two leads are required for electrical heating and piezoresistive sensing, the power required for heating of this resonator can be potentially lower than that of the oscillators with closed-loop oven control algorithm. It is also shown that the phase noise can be suppressed at the turnover temperature because of the very low value of the TCF, which justifies the usage of the heating voltage as the excitation voltage of the Wheatstone half-bridge.

  16. Reproducible microwave-assisted acid hydrolysis of proteins using a household microwave oven and its combination with LC-ESI MS/MS for mapping protein sequences and modifications.

    Science.gov (United States)

    Wang, Nan; Li, Liang

    2010-09-01

    A new set-up for microwave-assisted acid hydrolysis (MAAH) with high efficiency and reproducibility to degrade proteins into peptides for mass spectrometry analysis is described. It is based on the use of an inexpensive domestic microwave oven and can be used for low volume protein solution digestion. This set-up has been combined with liquid chromatography electrospray ionization quadrupole time-of-flight mass spectrometry (LC-ESI QTOF MS) for mapping protein sequences and characterizing phosphoproteins. It is demonstrated that for bovine serum albumin (BSA), with a molecular mass of about 67,000 Da, 1292 peptides (669 unique sequences) can be detected from a 2 microg hydrolysate generated by trifluoroacetic acid (TFA) MAAH. These peptides cover the entire protein sequence, allowing the identification of an amino acid substitution in a natural variant of BSA. It is shown that for a simple phosphoprotein containing one phosphoform, beta-casein, direct analysis of the hydrolysate generates a comprehensive peptide map that can be used to identify all five known phosphorylation sites. For characterizing a complex phosphoprotein consisting of different phosphoforms with varying numbers of phosphate groups and/or phosphorylation sites, such as bovine alpha(S1)-casein, immobilized metal-ion affinity chromatography (IMAC) is used to enrich the phosphopeptides from the hydrolysate, followed by LC-ESI MS analysis. The MS/MS data generated from the initial hydrolysate and the phosphopeptide-enriched fraction, in combination with MS analysis of the intact protein sample, allow us to reveal the presence of three different phosphoforms of bovine alpha(S1)-casein and assign the phosphorylation sites to each phosphoform with high confidence. 2010 American Society for Mass Spectrometry. Published by Elsevier Inc. All rights reserved.

  17. The klystron: A microwave source of surprising range and endurance

    Energy Technology Data Exchange (ETDEWEB)

    Caryotakis, G.

    1998-04-01

    This year marks the 60th anniversary of the birth of the klystron at Stanford University. The tube was the first practical source of microwaves and its invention initiated a search for increasingly more powerful sources, which continues to this day. This paper reviews the scientific uses of the klystron and outlines its operating principles. The history of the device is traced, from its scientific beginnings, to its role in World War II and the Cold War, and to its current resurgence as the key component in a major accelerator project. Finally, the paper describes the development of a modular klystron, which may someday power future accelerators at millimeter wavelengths.

  18. Microwave oven use for soil moisture content determination in different soils / Uso do forno de microondas na determinação da umidade em diferentes tipos de solo

    Directory of Open Access Journals (Sweden)

    Antonio Gabriel Filho

    2008-08-01

    Full Text Available In the present research the use of a microwave oven for the soil moisture content determination was analyzed, comparing the results with the values given by the conventional oven drying, using nine soils, with different textures. The results obtained by either method did not show appreciable differences for the soil samples. When the microwave oven was used, the variation among replicates decreased with the sample size and with the fine particles percentage in the soil. The regression analysis showed that a power law, y = kxn, adjusted the date with a large correlation (R = 0.9997 for all the soils. The n exponent values, near to the unity, indicated that the water removal mechanism showed a behavior near to the linearity in function of the time and that neither the initial water content nor the soil mass influenced the process. The k values in the regression equations showed that the process acts more intensively on clayey soils than on sandy ones. The experimental results allowed to conclude that the microwave oven may be used as an alternative to soil content measurement, resulting in time economy.No presente trabalho estudou-se a utilização do forno de microondas na determinação da umidade no solo, comparando-se os resultados com os valores fornecidos pelo método da estufa convencional, usando-se nove solos, com diferentes texturas. Os resultados obtidos por meio de qualquer um dos dois métodos não diferiram entre si. Quando se usou o método do microondas, as variações entre repetições diminuíram com o tamanho da amostra e com a percentagem de partículas finas no solo. A análise de regressão entre as variáveis tempo e umidade apresentou ajuste potencial do tipo y = kxn, com elevada correlação (R = 0,9997 para todos os solos estudados. Os valores do expoente n, todos próximos da unidade, indicaram que o mecanismo de retirada da água por microondas apresentou um comportamento quasi-linear em função do tempo e que os

  19. Radiation leakage from electromagnetic oven

    Directory of Open Access Journals (Sweden)

    Abdurrahman Khalil

    2015-10-01

    Results & Discussions: The measurements have been done at some houses in Erbil city, according to the source of background radiation exist before measuring data. Our data compared with standard safe range of radiation data. Results showed that there is radiation leak form all type of electromagnetic oven and all at the order of safety compared with standard value.

  20. Microwave Irradiation

    Indian Academy of Sciences (India)

    The rapid heating of food in the kitchen using microwave ovens ... analysis; application to waste treatment; polymer technology; .... Microwave heating for carrying out reactions on solids has also attracted considerable attention in recent years. For such 'dry media' reactions, solid supports such as alumina, silica and.

  1. Fast Drying of Agriculture Commodities by Using Microwave

    Science.gov (United States)

    Ode Ngkoimani, La; Megawati; Purwana Saputra, Gde; Cahyono, Edi; Aripin, Haji; Gde Suastika, Komang; Nyoman Sudiana, I.

    2017-05-01

    Some progress has been made and reported previously due to investigate microwave effects to materials. The microwave applications for material processing by using wide range microwave frequencies such as in sintering, chemical reaction, and drying have been performed. Microwave drying is based on a unique volumetric heating mode with electromagnetic radiation at 2,450 MHz. However, the quest for a what a true microwave effect is still plagued with difficulties. This paper provides a experimental and theoretical analysis of drying materials using microwave. For drying experiments, in this investigation, we were using a domestic microwave oven which operated at three power levels for drying chamber. The samples are agriculture commodity collected from local farmers. The experimental results show that microwave accelerate drying in most materials. The experimental data were analyzed by using an available model constructed from fundamental physics by other scholars. The model has been applied to more understanding the behavior of the microwave drying material.

  2. Microwave applications in neuromorphology and neurochemistry: safety precautions and techniques.

    Science.gov (United States)

    Marani, E

    1998-06-01

    In science, the introduction of a new method is never easy, not even if it concerns the use of a simple microwave oven. Most scientists do not realize the numerous applications of microwave techniques. This paper gives a broad overview of the application of microwave techniques in neuromorphology and neurochemistry, starting with a historical overview ranging from the introduction of microwave techniques as a scientific method in the 1970s to present. Organizations and publication rules are highlighted in the next part. The effect of microwave irradiation is discussed in two sections relating to microwave effects on the whole organism and on the neuron. The main body of the paper discusses the application of microwave techniques in the fields of neuromorphology and neuropathology. The paper then presents aspects of microwave irradiation as applied to ELISA techniques. In addition, cell fusion and cell reproduction under microwave irradiation are discussed. Copyright 1998 Academic Press.

  3. Plaster glue complex permittivity response in the microwave range

    Directory of Open Access Journals (Sweden)

    Antonio Jeronimo Belfort de Oliveira

    2004-12-01

    Full Text Available This paper describes a complementary method for determining dielectric properties of granular materials using the Transmission/Reflection Method in order to estimate their moisture content. The Newton's Complex Interactive Method is used here as a numerical tool to calculate the complex permittivity of the plaster glue material. Results for samples with moisture contents of 35%, 40% and 45% in the range of 100 MHz to 3 GHz are presented.

  4. Síntese de Al2O3/SiC em forno de microondas: estudo de parâmetros do processo Synthesis of Al2O3/SiC in microwave oven: study of the processing parameters

    Directory of Open Access Journals (Sweden)

    T. P. Deksnys

    2005-12-01

    Full Text Available Estudos demonstram a eficiência do método de moagem prévia do aluminossilicato precursor para a síntese da fase Al2O3/SiC por meio da reação de redução carbotérmica em forno de microondas. No presente trabalho, além da moagem do precursor, outros parâmetros de reação foram estudados, como tempo de reação, potência da radiação emitida e fluxo de gás. As reações foram realizadas em forno de microondas semi-industrial, com adaptação para inserção de gás inerte. Dois tipos de reatores foram avaliados: um reator cilíndrico, termicamente isolado, e um reator tubular de leito fixo, nos quais foram colocados os precursores peletizados. Existe uma relação direta entre a saturação da atmosfera de reação com a cinética de redução carbotérmica do aluminossilicato. Esse comportamento, aliado a elevadas potências de emissão, favorecem a formação da fase Al2O3/SiC em períodos de tempo reduzidos.Results presented elsewhere have confirmed the feasibility of the previous milling process of the starting materials for the synthesis of Al2O3/SiC by the microwave-assisted carbothermal reduction. In the present work, parameters such as precursor milling, reaction time, microwave's power level and gas flow have been investigated. Reactions were carried out in a semi-industrial microwave oven (Cober Inc., USA, which allowed the inert gas insertion. Two reactions arrangement were developed to perform the synthesis: a cylindrical reactor, thermally insulated and a pipe fluidized bed reactor. Into both reactors, the precursor was applied in a palletized form to react. There is a direct relation between the reaction atmosphere saturation and the kinetics of the carbothermal reduction. This behavior, in addiction to high power levels of microwave radiation (>1.5 KW, favors the formation of Al2O3/SiC in a short time.

  5. O uso de aparelhos de micro-ondas domésticos em aulas experimentais de química orgânica: nitração de salicilaldeído The use of domestic microwave oven in experimental classes of organic chemistry: salicylaldehyde nitration

    Directory of Open Access Journals (Sweden)

    Eurídes Francisco Teixeira

    2010-01-01

    Full Text Available The use of microwave in chemistry has known benefits over conventional heating methods, e.g. reduced reaction times, chemical yield improvement and the possibility if reducing or eliminating the use of organic solvents. We describe herein a procedure for the nitration of salicylaldehyde in water using a domestic microwave oven, which can be used as an experiment in the undergraduate chemistry laboratory. The experiment involves safe and rapid preparation and identification of the position isomers by thin layer chromatography and 1H NMR, or by their melting points.

  6. Filmes finos de SrBi2Ta2O9 processados em forno microondas SrBi2Ta2O9 thin films processed in microwave oven

    Directory of Open Access Journals (Sweden)

    J. S. Vasconcelos

    2003-03-01

    Full Text Available Filmes finos de SrBi2Ta2O9 foram depositados em substratos de Pt/Ti/SiO2/Si e, pela primeira vez, sinterizados em forno microondas doméstico. Os padrões de difração de raios X mostraram que os filmes são policristalinos. O processamento por microondas permite utilizar baixa temperatura na síntese e obter filmes com boas propriedades elétricas. Ensaios de microscopia eletrônica de varredura (MEV e de Força Atômica (MFA revelam boa aderência entre filme e substrato, com microestrutura de superfície apresentando grãos finos e esféricos e rugosidade de 4,7 nm. A constante dielétrica e o fator de dissipação, para freqüência de 100 KHz, à temperatura ambiente, foram de 77 e 0,04, respectivamente. A polarização remanescente (2Pr e o campo coercitivo (Ec foram 1,04 miC/cm² e 33 kV/cm. O comportamento da densidade de corrente de fuga revela três mecanismos de condução: linear, ôhmico e outro mecanismo que pode ser atribuído à corrente de Schottky. Dos padrões de DRX, análises das imagens por MEV e topografia de superfície por MFA observa-se que 10 min de tratamento térmico a 550 ºC, em forno microondas, é tempo suficiente para se obter a cristalização do filme.SrBi2Ta2O9 thin films were deposited on Pt/Ti/SiO2/Si substrates and, for the first time, sintered in a domestic microwave oven. The X-ray diffraction patterns showed that the films are polycrystalline. The microwave processing allows to use a low temperature for the synthesis, obtaining films with good electrical properties. Scanning Electron Microscopy (SEM and Atomic Force Microscopy (AFM results reveal good adherence between film and substrate and a surface microstructure presenting thin and spherical grains and roughness of 4.7 nm. The dielectric constant and the dissipation factor, for a frequency of 100 KHz at room temperature, were 77 and 0.04, respectively. The remaining polarization (2Pr and the coercive field (Ec were 1.04 C/cm² and 33 k

  7. 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%.

  8. Antigen retrieval in formalin-fixed, paraffin-embedded tissues: an enhancement method for immunohistochemical staining based on microwave oven heating of tissue sections.

    Science.gov (United States)

    Shi, S R; Key, M E; Kalra, K L

    1991-06-01

    We describe a new approach for retrieval of antigens from formalin-fixed, paraffin-embedded tissues and their subsequent staining by immunohistochemical techniques. This method of antigen retrieval is based on microwave heating of tissue sections attached to microscope slides to temperatures up to 100 degrees C in the presence of metal solutions. Among 52 monoclonal and polyclonal antibodies tested by this method, 39 antibodies demonstrated a significant increase in immunostaining, nine antibodies showed no change, and four antibodies showed reduced immunostaining. In particular, excellent immunostaining results were obtained with a monoclonal antibody to vimentin as well as several different keratin antibodies on routine formalin-fixed tissue sections after pre-treatment of the slides with this method. These results showed that after antigen retrieval: (a) enzyme predigestion of tissues could be omitted; (b) incubation times of primary antibodies could be significantly reduced, or dilutions of primary antibodies could be increased; (c) adequate staining could be achieved in long-term formalin-fixed tissues that failed to stain by conventional methods; and (d) certain antibodies which were typically unreactive with formalin-fixed tissues gave excellent staining.

  9. HAMP – the microwave package on the High Altitude and LOng range research aircraft (HALO

    Directory of Open Access Journals (Sweden)

    M. Mech

    2014-12-01

    Full Text Available An advanced package of microwave remote sensing instrumentation has been developed for the operation on the new German High Altitude LOng range research aircraft (HALO. The HALO Microwave Package, HAMP, consists of two nadir-looking instruments: a cloud radar at 36 GHz and a suite of passive microwave radiometers with 26 frequencies in different bands between 22.24 and 183.31 ± 12.5 GHz. We present a description of HAMP's instrumentation together with an illustration of its potential. To demonstrate this potential, synthetic measurements for the implemented passive microwave frequencies and the cloud radar based on cloud-resolving and radiative transfer model calculations were performed. These illustrate the advantage of HAMP's chosen frequency coverage, which allows for improved detection of hydrometeors both via the emission and scattering of radiation. Regression algorithms compare HAMP retrieval with standard satellite instruments from polar orbiters and show its advantages particularly for the lower atmosphere with a root-mean-square error reduced by 5 and 15% for temperature and humidity, respectively. HAMP's main advantage is the high spatial resolution of about 1 km, which is illustrated by first measurements from test flights. Together these qualities make it an exciting tool for gaining a better understanding of cloud processes, testing retrieval algorithms, defining future satellite instrument specifications, and validating platforms after they have been placed in orbit.

  10. Influência do uso do forno de microondas ou convencional na síntese de ZrO2 Influence of the use of microwave oven or conventional furnace on the synthesis of ZrO2

    Directory of Open Access Journals (Sweden)

    V. dos Santos

    2008-12-01

    Full Text Available O presente trabalho tem como objetivo descrever a síntese de óxido de zircônio, variando as condições de síntese com o uso de forno convencional (FC ou forno de microondas (FM, através do método Pechini. As características estruturais dos óxidos sintetizados foram determinadas por difração de raios X, infravermelho e análises térmicas. As propriedades morfológicas foram determinadas por microscopia eletrônica de varredura com emissão de campo e por isotermas de adsorção/desorção. O uso de FM ou FC, ou o uso de ambos para um mesmo óxido (FM + FC ou FC + FM apresentaram uma grande influência sobre o grau de cristalinidade dos materiais sintetizados.The present work deals with the synthesis of zirconium oxide under varying conditions of synthesis using conventional furnace (CF or microwave oven (MO, by the Pechini method. This study was carried out with the primary aim of studying the possible influence of the above parameters as synthesis variables on the structural and morphologic properties of ZrO2. The structural characteristics of the synthesized oxides were determined by X-ray diffractio, infrared and thermal analysis. The morphologic properties were determined by FEG-SEM and isothermal gas adsorption/desorption. The use of MO or CF, or both for the same oxide (MO+CF or CF+MO has great influence on the degree of crystallinity of the synthesized materials.

  11. Simulation of recording the microwave holograms of complex objects by the near range radars

    Directory of Open Access Journals (Sweden)

    V. V. Razevig

    2014-01-01

    Full Text Available Radar is an object-detection technology that uses radio waves to determine the presence, range, altitude, direction, or speed of objects. In the recent time, there is an increasingly arising interest to the near range microwave imaging that allows detection of the shape and, in some cases, the inner structure of the investigated objects.For design engineering and efficiency evaluation of the cutting-edge radars as well as for testing the developed recovery algorithms a set of microwave holograms of various objects obtained under different conditions is needed. Microwave holograms cannot be obtained only on the basis of the experimental researches related to the measurements of electromagnetic scattering by the real objects since such experiments are time consuming and quite expensive. Therefore, to simulate electromagnetic scattering processes via objects examination is quite a challenge.This investigation goal is to develop a computer simulation method to record the microwave holograms of complex objects by the near range radars.To specify the shape of the investigated objects, Autodesk 3ds Max (3D computer graphics program for making 3D animations, models, and images is used. At a second stage the surface of the created object is described by a set of triangular facets. While calculating the reflected field, a final representation of the object as a set of point reflectors is used. Thus, the model of single scattering, is used without taking into consideration re-reflection and cross-influence of reflectors.Methods are also described to form the focused images of the microwave holograms that allow us to obtain a function describing object reflectivity, by which in most cases an object shape can be easily recognized.A comparison of computer-simulated holograms with experimental data proves the model adequacy.The model can be used to find a dependence of the plane resolution on used frequency, step of scanning, and distance to the object and a

  12. Scattering in remote sensing in the visible and microwave spectral range and in traffic control

    Directory of Open Access Journals (Sweden)

    U. Böttger

    2003-01-01

    Full Text Available The treatment of scattering processes in remote sensing for interpretation of satellite data is demonstrated in the visible and microwave spectral range comparing the two spectral ranges. Analogies and distinctions in the treatment of the scattering processes are shown. Based on this cognition an approach for traffic simulation is outlined. Simulating the traffic of a part of a city, a whole city or a larger area in an acceptable time is one of the tasks in recent traffic research. One possible approach is the areal treatment of the road network. That means that single streets are not resolved but are introduced into simulations only by parameters that correspond to a specific traffic area resistance. The aim of this work is to outline such a possibility using experiences obtained from the theory of radiative transport to simulate scattering processes and applying them to the very complex system of traffic simulation.

  13. Semi-automated microwave assisted solid-phase peptide synthesis

    DEFF Research Database (Denmark)

    Pedersen, Søren Ljungberg

    Biotage Initiator microwave instrument, which is available in many laboratories, with a modified semi-automated peptide synthesizer from MultiSynTech. A custom-made reaction vessel is placed permanently in the microwave oven, thus the reactor does not have to be moved between steps. Mixing is achieved...... with microwaves for SPPS has gained in popularity as it for many syntheses has provided significant improvement in terms of speed, purity, and yields, maybe especially in the synthesis of long and "difficult" peptides. Thus, precise microwave heating has emerged as one new parameter for SPPS, in addition...... to coupling reagents, resins, solvents etc. We have previously reported on microwave heating to promote a range of solid-phase reactions in SPPS. Here we present a new, flexible semi-automated instrument for the application of precise microwave heating in solid-phase synthesis. It combines a slightly modified...

  14. Rapid and Decentralized Human Waste Treatment by Microwave Radiation.

    Science.gov (United States)

    Nguyen, Tu Anh; Babel, Sandhya; Boonyarattanakalin, Siwarutt; Koottatep, Thammarat

    2017-07-01

      This study evaluates the technical feasibility of using microwave radiation for the rapid treatment of human feces. Human feces of 1000 g were radiated with a commercially available household microwave oven (with rotation) at different exposure time lengths (30, 50, 60, 70, and 75 mins) and powers (600, 800, and 1000 W). Volume reduction over 90% occurred after 1000 W microwave radiation for 75 mins. Pathogen eradiation performances of six log units or more at a high range of microwave powers were achieved. Treatments with the same energy input of 1000 Wh, but at lower powers with prolonged exposure times, significantly enhanced moisture removal and volume reduction. Microwave radiation caused carbonization and resulted in a more stable end product. The energy content of the samples after microwave treatment at 1000 W and 75 mins is 3517 ± 8.85 calories/g of dried sample, and the product can also be used as compost.

  15. Delivering Microwave Spectroscopy to the Masses: a Design of a Low-Cost Microwave Spectrometer Operating in the 18-26 GHZ Frequency Range

    Science.gov (United States)

    Steber, Amanda; Pate, Brooks

    2014-06-01

    Advances in chip-level microwave technology in the communications field have led to the possibilities of low cost alternatives for current Fourier transform microwave (FTMW) spectrometers. Many of the large, expensive microwave components in a traditional design can now be replaced by robust, mass market monolithic microwave integrated circuits (MMICs). "Spectrometer on a board" designs are now feasible that offer dramatic cost reduction for microwave spectroscopy. These chip-level components can be paired with miniature computers to produce compact instruments that are operable through USB. A FTMW spectrometer design using the key MMIC components that drive cost reduction will be presented. Two dual channel synthesizers (Valon Technology Model 5008), a digital pattern generator (Byte Paradigm Wav Gen Xpress), and a high-speed digitizer/arbitrary waveform generator combination unit (Tie Pie HS-5 530 XM) form the key components of the spectrometer for operation in the 18-26.5 GHz range. The design performance is illustrated using a spectrometer that is being incorporated into a museum display for astrochemistry. For this instrument a user interface, developed in Python, has been developed and will be shown.

  16. MEMS Keys as a Way to Delay the Phase of the Microwave Range

    Directory of Open Access Journals (Sweden)

    Anton Antonenko

    2015-04-01

    Full Text Available The paper deals with a new type of phase shifter antennas scanned beam shows the principle of constructing controlled microwave phase shifters that have a low cost. Also, given the results of a theoretical study of the main characteristics of dependency - controlled phase shift and frequency band working on the design parameters and then refined by calculating finite element program CST Microwave Studio. These inexpensive scanned antenna can be used in radar centimeter and millimeter wavelengths in the frequency range 2 ¸ 30 GHz. The results of calculation of capacitive and inductive coupling during switching detector elements and the simulation results of the phase shift in passing through the phase shifter television signal containing includes microelectromechanical systems - manageable sections that have to change the direction of polarization of the signal. Thus for supplying voltage-controlled permanent magnet field is used. According to the simulation results, which are presented in the conclusions can be drawn about the development of the design of optimal geometric parameters, the values obtained for the results of the optimization modeling. However revealed a high quality factor switching phase.

  17. All-dielectric metamaterial: a ferroelectric-based scheme in the microwave range

    Science.gov (United States)

    Lepetit, Thomas; Akmansoy, Eric; Ganne, Jean-Pierre

    2009-08-01

    Dielectric metamaterials are an attractive alternative to metallic metamaterials in order to reduce losses. Mie resonances in dielectric resonators can give rise to a resonant effective permeability or permittivity at resonance frequencies. When resonances are sufficiently enhanced permeability or permittivity can become negative. In the microwave range 2D rodshaped or 3D cylinder-shaped resonators made of high-permittivity ferroelectric material can be used to demonstrate such phenomena. In the first part we present experimental proof for TE-modes in rod resonators in the X-band (8.20- 12.40GHz) using barium strontium titanate (Ba0.4Sr0.6TiO3, ɛ=575). In the second part we present experimental proof for modes in cylinder resonators in both the X and S-band (2.60-3.95GHz) using a commercial ceramic (ɛ=78). A negative index of refraction is shown in both cases.

  18. Facial burns from exploding microwaved foods: Case series and review.

    Science.gov (United States)

    Bagirathan, Shenbana; Rao, Krishna; Al-Benna, Sammy; O'Boyle, Ciaran P

    2016-03-01

    Microwave ovens allow for quick and simple cooking. However, the importance of adequate food preparation, prior to microwave cooking, and the consequences of inadequate preparation are not well-known. The authors conducted a retrospective outcome analysis of all patients who sustained facial burns from microwaved foods and were treated at a UK regional burns unit over a six-year period. Patients were identified from clinical records. Eight patients presented following inadequate preparation of either tinned potatoes (n=4) or eggs (n=4). All patients sustained burns. Mean age was 41 years (range 21-68 years). Six cases (75%) had associated ocular injury. One received amniotic membrane grafts; this individual's vision remains poor twelve months after injury. Rapid dielectric heating of water within foods may produce high steam and vapour pressure gradients and cause explosive decompression [1,5,11]. Consumers may fail to recognise differential heating and simply cook foods for longer if they remain cool on the outer surface. Education on safe use and risks of microwave-cooked foods may help prevent these potentially serious injuries. Microwave ovens have become ubiquitous. The authors recognise the need for improved public awareness of safe microwave cooking. Burns resulting from microwave-cooked foods may have life-changing consequences. Copyright © 2015 Elsevier Ltd and ISBI. All rights reserved.

  19. Hematite from Natural Iron Stones as Microwave Absorbing Material on X-Band Frequency Ranges

    Science.gov (United States)

    Zainuri, Mochamad

    2017-05-01

    This study has been investigated the effect of hematite as microwave absorbing materials (RAM) on X-Band frequency ranges. Hematite was succesfully processed by coprecipitation method and calcined at 500 °C for 5 hour. It was synthesized from natural iron stones from Tanah Laut, South Kalimantan, Indonesia. The products were characterized by X-ray diffraxtion (XRD), conductivity measurement, Vibrating Sample Magnetometer (VSM), and Vector Network Analyzer (VNA). The result was shown that hematite has conductivity value on (2.5-3).10-7 S/cm and be included as dielectric materials. The hysterisis curve was shown that hematite was a super paramagnetic materials. The product was mixed on paint with procentage 10% of total weight and coated on steel grade AH36 with spray methods. Then, the maximum of reflection loss on x - band’s frequency range (8,2-12,4) GHz was -7 dB on frequency of 10.5 GHz. It mean that almost 50% electromagnetic energy was absorbed by hematite.

  20. Circularly polarized microwaves for magnetic resonance study in the GHz range: Application to nitrogen-vacancy in diamonds

    Energy Technology Data Exchange (ETDEWEB)

    Mrózek, M., E-mail: mariusz.mrozek@uj.edu.pl; Rudnicki, D. S.; Gawlik, W. [Institute of Physics, Jagiellonian University, Lojasiewicza 11, 30-348 Krakow (Poland); Mlynarczyk, J. [Department of Electronics, AGH University of Science and Technology, Mickiewicza 30, 30-059 Krakow (Poland)

    2015-07-06

    The ability to create time-dependent magnetic fields of controlled polarization is essential for many experiments with magnetic resonance. We describe a microstrip circuit that allows us to generate strong magnetic field at microwave frequencies with arbitrary adjusted polarization. The circuit performance is demonstrated by applying it to an optically detected magnetic resonance and Rabi nutation experiments in nitrogen-vacancy color centers in diamond. Thanks to high efficiency of the proposed microstrip circuit and degree of circular polarization of 85%; it is possible to address the specific spin states of a diamond sample using a low power microwave generator. The circuit may be applied to a wide range of magnetic resonance experiments with a well-controlled polarization of microwaves.

  1. 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

  2. ENERGY STAR Certified Commercial Ovens

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 2.0 ENERGY STAR Program Requirements for Commercial Ovens that are effective as of...

  3. Ovenized microelectromechanical system (MEMS) resonator

    Energy Technology Data Exchange (ETDEWEB)

    Olsson, Roy H; Wojciechowski, Kenneth; Kim, Bongsang

    2014-03-11

    An ovenized micro-electro-mechanical system (MEMS) resonator including: a substantially thermally isolated mechanical resonator cavity; a mechanical oscillator coupled to the mechanical resonator cavity; and a heating element formed on the mechanical resonator cavity.

  4. Comparison between the conventional method of extraction of essential oil of Laurus nobilis L. and a novel method which uses microwaves applied in situ, without resorting to an oven.

    Science.gov (United States)

    Flamini, Guido; Tebano, Marianna; Cioni, Pier Luigi; Ceccarini, Lucia; Ricci, Andrea Simone; Longo, Iginio

    2007-03-02

    A novel microwave method has been applied to the hydrothermal extraction of essential oil from plants. An insulated microwave coaxial antenna was introduced inside a 1000 ml glass flask containing dry Laurus nobilis L. leaves and tap water. Microwave power up to 800 W at 2450 MHz was emitted in continuous wave regime (CW) or in pulsed regime (PR) at 8 kW peak power. Stirring with a magnetic bar and a Clevenger refrigerator connected to the flask enabled to complete the extraction in 1 h. The results of the in situ microwave extraction were compared with those obtained by heating the same reactor with a conventional electric mantle by gas chromatography-mass spectrometry (GC-MS) analysis. Differences were observed both in the composition of the essential oil and from the energetic point of view. The essential oil obtained with microwave (MW) methods contained substantially higher amounts of oxygenated compounds and lower amounts of monoterpenes than conventional method. The in situ microwave heating is safe and versatile; it presents time and energy saving advantages, and therefore it can be considered useful also for industrial applications.

  5. Controllable evaporation of cesium from a dispenser oven.

    Science.gov (United States)

    Fantz, U; Friedl, R; Fröschle, M

    2012-12-01

    This instrument allows controlled evaporation of the alkali metal cesium over a wide range of evaporation rates. The oven has three unique features. The first is an alkali metal reservoir that uses a dispenser as a cesium source. The heating current of the dispenser controls the evaporation rate allowing generation of an adjustable and stable flow of pure cesium. The second is a blocking valve, which is fully metallic as is the body of the oven. This construction both reduces contamination of the dispenser and enables the oven to be operated up to 300 °C, with only small temperature variations (dispenser oven can be easily transferred to the other alkali-metals.

  6. Solid-state pulsed microwave bridge for electron spin echo spectrometers of 8-mm wavelength range

    Directory of Open Access Journals (Sweden)

    Kalabukhova E. N.

    2012-12-01

    Full Text Available The article presents a construction of a coherent pulsed microwave bridge with an output power up to 10 Wt with a time resolution of 10–8 seconds at a pulse repetition rate of 1 kHz designed for electron spin echo spectrometers. The bridge is built on a homodyne scheme based on IMPATT diodes, which are used for modulation and amplification of microwave power coming from the reference Gunn diode oscillator. The advantages of the bridge are optimal power and minimum pulse width, simple operation, low cost.

  7. Microwave-assisted carbohydrohalogenation of first-row transition-metal oxides (M = V, Cr, Mn, Fe, Co, Ni, Cu) with the formation of element halides.

    Science.gov (United States)

    Berger, Matthias; Neumeyer, Felix; Auner, Norbert

    2013-10-21

    The anhydrous forms of first-row transition-metal chlorides and bromides ranging from vanadium to copper were synthesized in a one-step reaction using the relatively inexpensive element oxides, carbon sources, and halogen halides as starting materials. The reactions were carried out in a microwave oven to give quantitative yields within short reaction times.

  8. Microwave drying of wood strands

    Science.gov (United States)

    Guanben Du; Siqun Wang; Zhiyong Cai

    2005-01-01

    Characteristics of microwave drying of wood strands with different initial moisture contents and geometries were investigated using a commercial small microwave oven under different power inputs. Temperature and moisture changes along with the drying efficiency were examined at different drying scenarios. Extractives were analyzed using gas chromatography=mass...

  9. Mechanical characterization of microwave sintered zinc oxide

    Indian Academy of Sciences (India)

    The mechanical characterization of microwave sintered zinc oxide disks is reported. The microwave sintering was done with a specially designed applicator placed in a domestic microwave oven operating at a frequency of 2.45 GHz to a maximum power output of 800 Watt. These samples with a wide variation of density ...

  10. Microwave-assisted preparation of naphthenic acid esters

    Directory of Open Access Journals (Sweden)

    VERA CIRIN-NOVTA

    2006-12-01

    Full Text Available The synthesis of esters of natural petroleum acids of the naphthenic type assisted with microwave irradiation under the conditions of acid catalysis was carried out with various alcohols: methanol, ethanol, n-butanol and tert-butyl alcohol. Microwave dielectric heating of the reaction mixture in an unmodified microwave oven with activation of the naphthenic acids with sulfuric and p-toluenesulfonic acid afforded the esters of the naphthenic acids. Depending on the catalyst and the steric and nucleophilic properties of the alcohols, the yield of naphthenic esters ranged from 31.25 % to 88.90 %. As a consequence of microwave dielectric heating, the esterification time was reduced from 6–10 h to 5 min.

  11. Microwave Cooking: Knowledge, Attitudes, and Practices of California Foods Teachers.

    Science.gov (United States)

    Stalder, Laura D.; And Others

    1990-01-01

    A survey of 500 California secondary foods teachers (172 responses) indicated their understanding of microwave cooking principles and techniques and positive attitudes toward microwave cooking and safety. A majority used microwave instruction in their classrooms, although many indicated a need for ovens and microwave educational materials. (SK)

  12. The importance of signals in the Doppler broadening range for middle-atmospheric microwave wind and ozone radiometry

    Science.gov (United States)

    Rüfenacht, Rolf; Kämpfer, Niklaus

    2017-09-01

    Doppler microwave radiometry is a novel technique for the measurement of horizontal wind profiles at altitudes between 10 and 0.03 hPa, where there is a substantial lack of observations. All wind radiometers currently in use rely on ground-based observations of microwave radiation emitted by atmospheric ozone. Besides the well-known primary ozone layer in the stratosphere a secondary ozone layer forms near 10-3 hPa during nighttime. We show that the emission signal of this secondary ozone layer cannot be neglected for the retrieval of mesospheric winds and that it can even alter nighttime ozone retrievals. However, the present study also demonstrates that with a reasonably adequate representation of the atmospheric reality in the mesopause region bias-free wind retrievals throughout the entire sensitive altitude range of the instruments can be achieved during day and nighttime. By applying the improved ozone a priori setup to real observation data the average zonal wind difference to models was substantially reduced and a realistic diurnal cycle was reproduced. Moreover the presence of the high nighttime mesopause ozone signal could enable future retrievals of mean winds beyond the altitude range dominated by pressure broadening.

  13. A new and economic approach to synthesize and fabricate bioactive diopside ceramics using a modified domestic microwave oven. Part 2: effect of P2O5 additions on diopside bioactivity and mechanical properties.

    Science.gov (United States)

    Zouai, Souheila; Harabi, Abdelhamid; Karboua, Noureddine; Harabi, Esma; Chehlatt, Sihem; Barama, Salah-Edine; Zaiou, Soumia; Bouzerara, Ferhat; Guerfa, Fatiha

    2016-04-01

    In this work, diopside based ceramics was obtained by solid state reaction using conventional sintering (CS) and microwave sintering (MS). Moreover, different amounts of P2O5 (0.5-5.0 wt.%) have been added. It has been found that a relative density up to 95% theoretical was obtained for diopside containing 2.0 and 5.0 wt.% P2O5, sintered at 1250 °C for 2h and at 1075 °C only for 15 min using CS and MS. Excellent values of micro hardness (7.4 ± 0.1 GPa) and 3 point flexural strength (about 270 MPa) for samples containing 5 wt.% P2O5, sintered at 1075 °C for 15 min using MS were measured. Besides this, a relatively low weight loss ratio has been measured (0.01%) for diopside samples containing 5 wt.% P2O5, sintered under the same conditions, after soaking in physiological salt solution for 2 days. Additionally, the bioactivity of diopside by the possibility of formation of apatite on the surface of pure diopside and diopside containing 2 wt.% of P2O5 immersed in simulated body fluid (SBF) was also confirmed. Finally, particular nano-sized of Carbonated hydroxyapatite (CHA) crystals (rice shaped) were formed and covered the surface of these samples, soaked in SBF solution for 14 days. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. "Zolotoi Oven" ishtshet svojego obladatelja / Valeri Kuznetsov

    Index Scriptorium Estoniae

    Kuznetsov, Valeri

    2003-01-01

    Parima filmi auhinnale "Zolotoi Oven" võistlevad Andrei Zvjagintsevi "Tagasitulek" ("Vozvrashtshenije"), Vadim Abdrashitovi "Magnettormid" ("Magnitnõje buri"), Gennadi Sidorovi "Vanaeided" ("Staruhhi") ja Pjotr Buslovi "Bumer"

  15. High-dynamic-range and high-capacity RF and microwave fiber optic links

    Science.gov (United States)

    Weiss, Frank

    2013-05-01

    Novel fiber optic transmitter control methodologies, high optical power and low RIN source lasers, high performance photodiodes and DWDM laser capability provide high dynamic range and high capacity transport for a wide range of sensing and communications applications. Measured component and system level test data demonstrates these performance improvements. Higher spur free dynamic range in excess of 110 dB·Hz2/3 over broad range of K-band frequencies is demonstrated, increasing the practical use of fiber as a transport method for high sensitivity applications. Multichannel DWDM operation provides simplified capacity expansion without compromising system performance, allowing arrayed photonic systems to be deployed. System characterization for a wide range of optical wavelengths and RF frequencies is provided to demonstrate these levels of performance in practical applications. Photonic component cost reductions combined with compact packaging further increase the ability of high performance fiber optic transport to address a wider range of applications, as the size, weight and performance barriers are eliminated. This paper provides a summary of the current state of the art of commercially available photonic components for high performance externally modulated analog optical links from a practical perspective.

  16. Heating of matter by microwaves without convection

    OpenAIRE

    Drašković, Draško

    2012-01-01

    This thesis considers heating of matter by means of microwaves. The most common device that uses micro waves for the heating of matter is the microwave oven. Because of the microwave ovens ubiquity and accessibility there are many articles that address the way it works and in how it heats matter. However, it appears that articles contradict each other in their claims that the heating of the matter is either from the inside or from the outside. What actually means »heating the material in the...

  17. Effects of microwave radiation on living tissues

    Energy Technology Data Exchange (ETDEWEB)

    Surrell, J.A.; Alexander, R.C.; Cohle, S.D.; Lovell, F.R. Jr.; Wehrenberg, R.A.

    1987-08-01

    Prompted by an alleged case of child abuse resulting from microwave oven burns and the discovery of one other case, an animal model was chosen to explore microwave burn characteristics upon living, perfusing tissue. Anesthetized piglets were exposed to radiation from a standard household microwave oven for varying lengths of time, sufficient to result in full-thickness skin and visceral burns. Characteristic burn patterns were grossly identified. Biopsies studied with both light and electron microscopy demonstrated a pattern of relative layered tissue sparing. Layered tissue sparing is characterized by burned skin and muscle, with relatively unburned subcutaneous fat between these two layers. These findings have important forensic and patient care implications.

  18. Electromagnetic properties of LaCa3Fe5Oi2 in the microwave range

    Science.gov (United States)

    Golenkina, V. V.; Ghyngazov, S. A.; Suslyaev, V. I.; Korovin, E. Yu; Kuleshov, G. E.; Kaykenov, D. A.; Mustafin, E. S.; Mylnikova, T. S.

    2016-02-01

    The X-ray diffraction analysis of the LaCa3Fe5O12 ferrite (lanthanum ferrite) prepared through high-temperature synthesis via ceramic technology was performed. It was found that ferrites belong to tetragonal system. The electromagnetic response from a flat layer of the composite based on this material under electromagnetic radiation in the frequency range of 0.01-18 GHz was investigated. It is shown that the developed material effectively interacts with electromagnetic radiation. The interaction effectiveness is directly proportional to ferrite concentration. Increased concentration of ferrite leads to growth of the reflection coefficient due to high conductivity of the material and visible decrease in the transmission coefficient in the frequency range of 4-14 GHz.

  19. [Dielectric parameters of ascitic and pleural fluids in the microwave range in different nosologies].

    Science.gov (United States)

    Romanov, A N; Kovrigin, A O; Grigorchuk, O G; Lubennikov, V A; Lazarev, A F

    2011-01-01

    The dielectric parameters of ascitic and pleural fluids formed in the human body in oncological and nononcological diseases of different nosology have been estimated in the range between 400 MHz and 1.2 GHZ. The dependence of refractive and absorption indices of ascitic and pleural liquids on the signal frequency and mass concentration of dissolved substances was found. Common regularities and distinctions in the behavior of their dielectric properties were revealed.

  20. Salt for the earthen oven revisited

    African Journals Online (AJOL)

    Test

    2011-06-07

    Jun 7, 2011 ... translated: 'you are the salt of the earthen oven', whilst Luke. 12:49 is ... The Palestinian Arabic word for kiln oven, ̛arsִa, confirms this understanding (De ..... 2000, A Greek-English Lexicon of the New Testament and Other.

  1. experimental investigation of the effect of microwave drying and ...

    African Journals Online (AJOL)

    Alayande Ibraheem

    Effect of microwave oven drying and reactor temperature has been ... sample was water washed to remove excess alkali metal present through hydrolysis, sun dried .... difficult to explain. .... Cylinder Pyrolysis”, Journal of Thermal Science and.

  2. Microwave thawing of frozen parenteral solutions.

    Science.gov (United States)

    Walter, C W; Pauly, J A; Ausman, R K; Kundsin, R B; Holmes, C J

    1983-01-01

    A commercially available microwave oven modified for use at medication stations throughout hospitals allows timely thawing of frozen parenteral solutions. The inherent problems of safety and uniform heating have been overcome, thus making possible the preparation, storage, and distribution of admixtures on a regional basis and ensuring the integrity of the product. Most parenteral medications are not degraded by microwave energy, and thawing by microwave energy permits timely administration and allows coordination of medication for a series of patients.

  3. Main principles of passive devices based on graphene and carbon films in microwave-THz frequency range

    Science.gov (United States)

    Kuzhir, Polina P.; Paddubskaya, Alesia G.; Volynets, Nadezhda I.; Batrakov, Konstantin G.; Kaplas, Tommi; Lamberti, Patrizia; Kotsilkova, Rumiana; Lambin, Philippe

    2017-07-01

    The ability of thin conductive films, including graphene, pyrolytic carbon (PyC), graphitic PyC (GrPyC), graphene with graphitic islands (GrI), glassy carbon (GC), and sandwich structures made of all these materials separated by polymer slabs to absorb electromagnetic radiation in microwave-THz frequency range, is discussed. The main physical principles making a basis for high absorption ability of these heterostructures are explained both in the language of electromagnetic theory and using representation of equivalent electrical circuits. The idea of using carbonaceous thin films as the main working elements of passive radiofrequency (RF) devices, such as shields, filters, polarizers, collimators, is proposed theoretically and proved experimentally. The important advantage of PyC, GrI, GrPyC, and GC is that, in contrast to graphene, they either can be easily deposited onto a dielectric substrate or are strong enough to allow their transfer from the catalytic substrate without a shuttle polymer layer. This opens a new avenue toward the development of a scalable protocol for cost-efficient production of ultralight electromagnetic shields that can be transferred to commercial applications. A robust design via finite-element method and design of experiment for RF devices based on carbon/graphene films and sandwiches is also discussed in the context of virtual prototyping.

  4. Bread ovens in Northern Oretania

    Directory of Open Access Journals (Sweden)

    García Huerta, Rosario

    2006-06-01

    Full Text Available This paper intends to bring to light an unusual type of domestic structure in the northern Oretania, namely the ovens used for the production of bread. The study of their distribution, as well as their dimensions and constructive features, indicates they are more complex structures, with collective or communal characters. At the same time, it gives us some knowledge of the internal organization of the main oritanian oppidas.

    Este artículo pretende dar a conocer un tipo de estructura doméstica poco habitual en la Oretania septentrional, como son los hornos destinados a la producción de pan. El análisis de su distribución, así como sus dimensiones y características constructivas, revela que se trata de estructuras más complejas, de carácter colectivo o comunal, lo que permite aproximarnos al conocimiento de la articulación interna de los principales oppida oretanos.

  5. Sterilization of instruments in solar ovens

    National Research Council Canada - National Science Library

    Jørgensen, A.F; Nøhr, K; Boisen, F; Nøhr, J

    2002-01-01

    ...: A solar oven was designed and manufactured using local materials and simple tools. It was tested by physical, chemical and microbiological methods and, after successful testing, installed in a rural clinic...

  6. Microwave Assisted Wolff-Kishner Reduction Reaction

    Science.gov (United States)

    Parquet, Eric; Lin, Qun

    1997-10-01

    A Wolff-Kishner reduction of a carbonyl group was carried out in a household microwave oven. Isatin was first converted to the hydrazone with 55% hydrazine and ethylene glycol by irradiation in the microwave oven at medium power for 30 seconds. Then, isatin 3-hydrazone was mixed with ethylene glycol and potassium hydroxide and irradiated in the microwave oven for only 10 seconds. After simple work-up and recrystallization, oxindole was obtained in a yield of 32.4%. The two step syntheses described here offer several advantages: (1) very short reaction time with no need for special microscale glassware, (2) mild experimental conditions (hot oil baths and heating mantles are not required), (3) the reagents are easy to handle (students do not need to prepare sodium ethoxide from sodium metal and absolute ethanol).

  7. The Histological effects of microwave oven on bone decalcification ...

    African Journals Online (AJOL)

    This study evaluates the histological preservation of bone tissue architecture at varying temperatures and concentrations of Gooding and Stewart (GS) decalcifying fluid as the preservation of tissue architecture depends on the quality and velocity of the decalcification processes. In the present study, a decalcification ...

  8. Microwave produced plasma in a Toroidal Device

    Science.gov (United States)

    Singh, A. K.; Edwards, W. F.; Held, E. D.

    2010-11-01

    A currentless toroidal plasma device exhibits a large range of interesting basic plasma physics phenomena. Such a device is not in equilibrium in a strict magneto hydrodynamic sense. There are many sources of free energy in the form of gradients in plasma density, temperature, the background magnetic field and the curvature of the magnetic field. These free energy sources excite waves and instabilities which have been the focus of studies in several devices in last two decades. A full understanding of these simple plasmas is far from complete. At Utah State University we have recently designed and installed a microwave plasma generation system on a small tokamak borrowed from the University of Saskatchewan, Saskatoon, Canada. Microwaves are generated at 2.45 GHz in a pulsed dc mode using a magnetron from a commercial kitchen microwave oven. The device is equipped with horizontal and vertical magnetic fields and a transformer to impose a toroidal electric field for current drive. Plasmas can be obtained over a wide range of pressure with and without magnetic fields. We present some preliminary measurements of plasma density and potential profiles. Measurements of plasma temperature at different operating conditions are also presented.

  9. FDTD modeling of EM field inside microwave cavities

    CERN Document Server

    Narayan, Shiv; Kanth, V Krushna

    2017-01-01

    This book deals with the EM analysis of closed microwave cavities based on a three-dimensional FDTD method. The EM analysis is carried out for (i) rectangular microwave ovens and (ii) hybrid-cylindrical microwave autoclaves at 2.45 GHz. The field distribution is first estimated inside domestic rectangular ovens in xy-, yz-, and zx-plane. Further, the RF leakage from the oven door is determined to study the effect of leakage radiation on wireless communication at 2.45 GHz. Furthermore, the EM analysis of the autoclave is carried out based on 3D FDTD using staircase approximation. In order to show the capability of autoclaves (excited with five source) for curing the aerospace components and materials, the field distribution inside autoclave cavity is studied in presence of aerospace samples. The FDTD based modelling of oven and autoclave are explained with the appropriate expressions and illustrations.

  10. Release of fumigant residues from grain by microwave irradiation.

    Science.gov (United States)

    Ren, Y L; Desmarchelier, J M

    1998-01-01

    Multiresidue analysis of fumigants is important because of their widespread use on staple foodstuffs, such as grain. Fumigants are usually extracted from grain either by solvent extraction or by purge-and-trap techniques. In this paper, fumigant residues in wheat were "extracted" by a microwave procedure. Wheat, in gas-tight Erlenmeyer flasks, was placed in a domestic microwave oven, and fumigants were released into the headspace by microwave irradiation. Power settings for maximum release of fumigants were determined for CH3Br, PH3, CS2, and COS. Recoveries of fortified samples were > 90%. Completeness of extraction was assessed from the amount of fumigant retained by the microwave-irradiated wheat. This amount, determined from both solvent extraction and from further microwave irradiation, was always small (microwave method is rapid and solvent-free. However, care is required in selecting the appropriate power setting. The safety implications of heating sealed flasks in microwave ovens should be noted.

  11. Analysis of temperature profile and electric field in natural rubber glove due to microwave heating: effects of waveguide position

    Science.gov (United States)

    Keangin, P.; Narumitbowonkul, U.; Rattanadecho, P.

    2018-01-01

    Natural rubber (NR) is the key raw material used in the manufacture of other products such as rubber band, tire and shoes. Recently, the NR is used in natural rubber glove ( NRG) manufacturing in the industrial and medical fields. This research aims to investigate the electromagnetic wave propagation and heat transfer in NRG due to heating with microwave energy within the microwave oven at a microwave frequency of 2.45 GHz. Three-dimensional model of NRG and microwave oven are considered in this work. The comparative effects of waveguide position on the electric field and temperature profile in NRG when subjected to microwave energy are discussed. The finite element method (FEM) is used to solve the transient Maxwell’s equation coupled with the transient heat transfer equation. The simulation results with computer programs are validated with experimental results. The placement of waveguides in three cases are left hand side of microwave oven, right hand side of microwave oven and left and right hand sides of microwave oven are investigated. The findings revealed that the placing the waveguide on the right side of the microwave oven gives the highest electric field and temperature profile. The values obtained provide an indication toward understanding the study of heat transfer in NRG during microwave heating in the industry.

  12. Simple microwave preionization source for ohmic plasmas

    Science.gov (United States)

    Choe, W.; Kwon, Gi-Chung; Kim, Junghee; Kim, Jayhyun; Jeon, Sang-Jean; Huh, Songwhe

    2000-07-01

    A simple economical 2.45 GHz microwave system has been developed and utilized for preionization on the Korea Advanced Institute of Science and Technology (KAIST)-TOKAMAK. The magnetron microwave source was obtained from a widely used, household microwave oven. Since ac operation of the magnetron is not suitable for tokamak application, the magnetron cathode bias circuit was modified to obtain continuous and stable operation of the magnetron for several hundred milliseconds. Application of the developed microwave system to KAIST-TOKAMAK resulted in a reduction of ohmic flux consumption.

  13. Microwave Heating of TV-Dinner Type Products

    Science.gov (United States)

    Modified from an inverter-based microwave oven, a new microwave system was developed to pasteurize mechanically tenderized beef, inoculated with Escherichia coli O157:H7 and placed into a 12 oz CPET tray containing de-ionized water. The system allowed the sample surface temperature to first increas...

  14. Critical factors in microwave expansion of starchy snacks

    NARCIS (Netherlands)

    Sman, van der R.G.M.; Bows, J.R.

    2017-01-01

    Popping of starchy pellets in a domestic microwave oven has proven difficult compared to pellets expanded in frying oil, and even to microwave expanded popcorn. These pellets encounter problems like uneven popping, burning and the absence of an audible cue for the end of popping. The lack of a

  15. 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)

  16. Determining the Quality Factor of Dielectric Ceramic Mixtures with Dielectric Constants in the Microwave Frequency Range.

    Science.gov (United States)

    Chen, Hetuo; Fu, Xuewen; An, Qi; Tang, Bin; Zhang, Shuren; Yang, Hao; Long, Yin; Harfouche, Mark; Wang, Huolei; Li, Yingxiang

    2017-10-26

    Microwave dielectric ceramic materials are extensively utilized in microwave applications because of their high dielectric constants and quality factors. These applications also require ceramics of zero temperature coefficients at the resonant frequency (τ f ), which can be realized through mixing a ceramic that one is interested in with another ceramic with -τ f , or by performing the ionic substitution. With the mixing/ionic substitution, it is indispensable to compute the quality factors precisely. Previous study indicates that the quality factor depends on the grain size, porosity, internal strain, structure, phase evolution, and conductivity etc. Here we derive a quality factor formula based on the definition, which works very well for multiphase composites, single phase solid solutions, and equivalent ionic substituted single phase materials. Our formula calculation and fits to the previous experimental results demonstrate that the quality factor of the ceramic mixtures strongly depend on the dielectric constants and the dielectric constant variation index. Our results suggest that the impacts from grain size, porosity, and internal strain etc. can be summarized to the dielectric constant or dielectric constant variation index, which is of great importance for future design of high performance microwave dielectric ceramics.

  17. Microwave heating of infant formula and breast milk.

    Science.gov (United States)

    Nemethy, M; Clore, E R

    1990-01-01

    Heating infant formula and breast milk in a microwave oven has become a common practice in many households. A review of the literature is presented to ascertain if there is evidence to support the safety of this practice, as well as to determine if microwaving affects the nutritional content of the heated milk. The results of a local community's survey are presented, which assesses parental use of microwave ovens in the heating of infant formula and parents' knowledge of the potential hazards of this practice.

  18. Fine and ultrafine particle emissions from microwave popcorn.

    Science.gov (United States)

    Zhang, Q; Avalos, J; Zhu, Y

    2014-04-01

    This study characterized fine (PM2.5 ) and ultrafine particle (UFP, diameter popcorn and analyzed influential factors. Each pre-packed popcorn bag was cooked in a microwave oven enclosed in a stainless steel chamber for 3 min. The number concentration and size distribution of UFPs and PM2.5 mass concentration were measured inside the chamber repeatedly for five different flavors under four increasing power settings using either the foil-lined original package or a brown paper bag. UFPs and PM2.5 generated by microwaving popcorn were 150-560 and 350-800 times higher than the emissions from microwaving water, respectively. About 90% of the total particles emitted were in the ultrafine size range. The emitted PM concentrations varied significantly with flavor. Replacing the foil-lined original package with a brown paper bag significantly reduced the peak concentration by 24-87% for total particle number and 36-70% for PM2.5 . A positive relationship was observed between both UFP number and PM2.5 mass and power setting. The emission rates of microwave popcorn ranged from 1.9 × 10(10) to 8.0 × 10(10) No./min for total particle number and from 134 to 249 μg/min for PM2.5 . © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  19. THE PROBLEM OF HOT-SPOTS IN MICROWAVE EQUIPMENT USED FOR PREPARATORY TECHNIQUES - THEORY AND PRACTICE

    NARCIS (Netherlands)

    KOK, LP; BOON, ME; SMID, HM

    1993-01-01

    Electron microscopists who wants to use a microwave (MW) oven to stimulate preparatory processes are sooner or later confronted with the problem of hot spots. It soon becomes clear to the user of any MW oven that the energy distribution-thus the speed of absorbing energy, and hence warming up-varies

  20. Optimized 3-D electromagnetic models of composite materials in microwave frequency range: application to EMC characterization of complex media by statistical means

    Directory of Open Access Journals (Sweden)

    S. Lalléchère

    2017-05-01

    Full Text Available The aim of this proposal is to demonstrate the ability of tridimensional (3-D electromagnetic modeling tool for the characterization of composite materials in microwave frequency band range. Indeed, an automated procedure is proposed to generate random materials, proceed to 3-D simulations, and compute shielding effectiveness (SE statistics with finite integration technique. In this context, 3-D electromagnetic models rely on random locations of conductive inclusions; results are compared with classical electromagnetic mixing theory (EMT approaches (e.g. Maxwell-Garnett formalism, and dynamic homogenization model (DHM. The article aims to demonstrate the interest of the proposed approach in various domains such as propagation and electromagnetic compatibility (EMC.

  1. Preparation and Characterization of Some Nanometal Oxides Using Microwave Technique and Their Application to Cotton Fabrics

    National Research Council Canada - National Science Library

    Gouda, M; Aljaafari, A; Al-Fayz, Y; Boraie, W. E

    2015-01-01

    .... Cotton fabrics containing nanometal oxides were prepared via a thiol-modification of cotton fabric samples and then dipped into the metal salt solutions precursors and transferred to the microwave oven...

  2. Microwave applications to rock specimen drying in laboratory

    Science.gov (United States)

    Park, Jihwan; Park, Hyeong-Dong

    2014-05-01

    Microwave heating is the process in which electromagnetic wave with 300 MHz - 300 GHz heats dielectric material. Although in the beginning microwave was mainly used in food industry to cook or heat the food, it soon became clear that microwave had a large potential for other applications. It was thus introduced in geological fields of investigation like mineral processing, oil sand and oil shale extraction, soil remediation, waste treatment. However, the drying techniques using microwave was rarely treated in geology field. According to the ISRM suggested methods, experimental rock specimens in laboratory test were dried in 105°C oven for a period of at least 24 hours. In this method, hot air transmits heats to material by means of thermal conduction, and the heat was transferred from the surface to the inside of the rock specimens. The thermal gradient and moisture gradient can deteriorate the specimens, and energy can be wasted in bulk heating the specimens. The aim of our study was to compare physical property, microstructural property, and energy efficiency between microwave drying method and conventional oven drying method, and to suggest new method for rock drying. Granite, basalt, and sandstone were selected as specimens and were made in cylinder shape with 54 mm diameter. To compare two different methods, one set of saturated specimens were dried in 105°C conventional oven and the other set of saturated specimens were dried in microwave oven. After dried, the specimens were cooled and saturated in 20°C water 48 hours. The saturation-drying were repeated 50 cycles, and the physical property and microstructural property were measured every 10 cycles. Absorption and elastic wave velocity were measured to investigate the change of physical property, and microscope image and X-ray computed tomography image were obtained to investigate the change of microstructural property of rock specimens. The electricity consumption of conventional oven and microwave oven

  3. Microwave Fun: User-Friendly Recipe Cards.

    Science.gov (United States)

    Bergstrom, Tom; And Others

    1995-01-01

    This article explains how a 12-year-old boy with profound mental retardation and autistic behaviors, living in a group home, was taught to follow number- and color-coded directions so that he could independently cook his own meals in a microwave oven. The article covers materials used, the skills taught, adaptations for classroom use, and safety…

  4. Influence of microwave and conventional cooking on beef liver lipids

    OpenAIRE

    Farag, R. S.; Abu-Raiia, S. H.; Al-Asfahany, A. M.

    1992-01-01

    Liver slices were cooked with a mixture of cottonseed oil and margarine using microwave oven and gas cooker. The acid values, peroxide numbers, total sterols and fatty acid profiles of unheated and cooked liver slices conventionally and by microwaves were determined. The time required for cooking liver slices by microwaves was one-half of the time required conventionally. Heating the lipid mixture by both heating methods caused highly significant decrease in the acid value. Conversely, the ac...

  5. Influence of Internal Temperatures of Soil on Soil Drying Curves by the Microwave Heating

    OpenAIRE

    UEDA, Kazuo

    1995-01-01

    The development of the method of quick determination of water content by microwaves has being watched with keenest interest by soil mechanics and foundation engineers. A certain number of experimental works have made it clear that the microwave oven functions well for the present compared to JIS method. In detailed observation, usually it was observed in a conventional oven that soil sample with low wet density required shorter than the time for drying of the one with high wet density. But, d...

  6. A computer model for estimating microwave propagation characteristics along earth-space paths in the 1-100 GHz range

    Science.gov (United States)

    Jackson, William C.

    A comprehensive, integrated, and transportable software package for the analysis of digital satellite links is presented. The most notable feature of this software is the inclusion of sophisticated models for attenuation and noise sources. The attenuation-source model takes into account losses due to rain, clouds, wet radomes, and multipath fading, as well as atmospheric absorption, defocusing, and scintillation. The noise-source model considers the radio noise due to the above absorptive losses, as well as extraterrestrial and man-made noise. Together, these models provide a fairly accurate representation of microwave propagation characteristics as they relate to satellite links. The software itself is designed to maximize the user's efficiency and minimize confusion. Menus are used extensively to guide the user through the program, and the use of prompting and input validity checking ensure the accuracy of all data entries. Color displays are used to present the data in an organized, easy-to-read format.

  7. Ultra fast synthesis of zinc oxide nanostructures by microwaves

    Science.gov (United States)

    Tabet, N.; Al Ghashani, R.; Achour, S.

    2009-06-01

    We describe a novel route for the synthesis of nanostructured zinc oxide powder using a modified kitchen microwave. A SiC-based composite showing a very strong absorption of microwaves was used as a microwave heater. Tests showed that high temperatures exceeding 1700 ∘C can be reached in less than hundred second exposure of the composite material of microwaves. Zinc oxide nanopowder was obtained by evaporation and oxidation of metallic zinc in the ambient atmosphere of the microwave oven. Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) techniques revealed the prepared powder includes a wide variety of nanostructures including nanoparticles, nanosheets and tetrapods.

  8. Microwave enhanced stabilization of heavy metal sludge.

    Science.gov (United States)

    Hsieh, Ching-Hong; Lo, Shang-Lien; Chiueh, Pei-Te; Kuan, Wen-Hui; Chen, Ching-Lung

    2007-01-02

    A microwave process can be utilized to stabilize the copper ions in heavy metal sludge. The effects of microwave processing on stabilization of heavy metal sludge were studied as a function of additive, power, process time, reaction atmosphere, cooling gas, organic substance, and temperature. Copper leach resistance increased with addition of aluminum metal powder, with increased microwave power, increased processing time, and using a gaseous environment of nitrogen for processing and air for cooling [N2/air]. The organic in the sludge affected stabilization, whether or not the organic smoldered. During heating in conventional ovens, exothermic oxidation of the organic resulted in sludge temperatures of about 500 degrees C for oven control temperatures of 200-500 degrees C. After microwave heating dried the sludge, the sludge temperature rose to 500 degrees C. The reaction between copper ions and metal aluminum in the dried sludge should be regarded as a solid phase reaction. Adding aluminum metal powder and reaction temperature were the key parameters in stabilizing copper in the heavy metal sludge, whether heated by microwave radiation or conventional oven. The mass balance indicates insignificant volatization of the copper during heating.

  9. Optimizaton of extraction of betalain pigments from beta vulgaris peels by microwave pretreatment

    Science.gov (United States)

    Singh, Aruna; Ganesapillai, Mahesh; Gnanasundaram, Nirmala

    2017-11-01

    The effect of microwave assissted extraction of pigments from beetroot peels was studied. Oven Drying followed by microwave assisted extraction was decided as the experimental procedure to be followed because of better absorbance in the range of 0.2-0.4. A microwave assisted extraction procedure is said to open the vacuolar pores inside beetroot powder.The Box-Behnken method was used as the RSM optimization technique. A quadratic model was suggested for both the solvents used. The optimized conditions for Solvent A were pH 5.20, Microwave Power of 224.61MW and Time 57.06 seconds for a Betanin Concentration of 229.264mg/L. The optimized conditions for Solvent B were found to be pH4.74, Microwave Power 384.25MW, Time 74.91 seconds and Betanin Concentration 472.113mg/L. The order of the extraction process was calculated as 1.42 and the rate constant as 0.00126. FTIR results confirm similar functional groups before and after the treatment. FTIR results confirm the presence of O–H stretch, C-H stretch, H–bonded, C-C stretch, N–H bend.

  10. Charcoal/LPG cooker, oven, and boiler

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, B.F.

    1995-06-22

    An insulated hot plate cooker that conserves heat in the exhaust of burning charcoal or domestic gas (LPG) and redirects said heat to do additional cooking, or baking, barbecuing, food preservation by drying, toasting, etc., and then redirecting exhaust heat from this compartment to a boiler that produces boil water, coffee, tea, etc.; thus, an energy-saving multi-purpose cooker with oven and boiler that has 80% efficiency. Combustion chamber of cooker is well ventilated and needs no fan or blower. Boiler has good heat conducting exhaust pipes that are submerged in water, and heat in the exhaust is extracted by the pipe to heat the surrounding water. (author) figs.

  11. Laureatõ premii "Zolotoi Oven"

    Index Scriptorium Estoniae

    2003-01-01

    Parima filmi auhinna "Zolotoi Oven" võitis Andrei Zvjagintsevi "Tagasitulek" ("Vozvrashtshenije"), Vadim Abdrashitovi "Magnettormid" ("Magnitnõje buri") sai parima režissööri ja parima stsenaristi auhinna (Aleksandr Mindadze), Pjotr Buslovi "Bumer" sai vaid muusikaauhinna (Sergei Shnurov). Parim meesnäitleja oli Viktor Suhhorukov ("Vaene, vaene Paul") ja naisnäitleja Maria Zvonarjeva A. Proshkini "Trios". A. Sokurovi "Isa ja poeg" sai vaid kunstnikuauhinna (Natalja Kotshergina). Inna Tshurikova sai kõrvalosa auhinna ("S: Govoruhhini "Blagoslovite zhenshtshinu")

  12. Plasma Properties of Microwave Produced Plasma in a Toroidal Device

    Science.gov (United States)

    Singh, Ajay; Edwards, W. F.; Held, Eric

    2011-10-01

    We have modified a small tokamak, STOR-1M, on loan from University of Saskatchewan, to operate as a low-temperature (~5 eV) toroidal plasma machine with externally induced toroidal magnetic fields ranging from zero to ~50 G. The plasma is produced using microwave discharges at relatively high pressures. Microwaves are produced by a kitchen microwave-oven magnetron operating at 2.45 GHz in continuous operating mode, resulting in pulses ~0.5 s in duration. Initial measurements of plasma formation in this device with and without applied magnetic fields are presented. Plasma density and temperature profiles have been measured using Langmuir probes and the magnetic field profile inside the plasma has been obtained using Hall probes. When the discharge is created with no applied toroidal magnetic field, the plasma does not fill the entire torus due to high background pressure. However, when a toroidal magnetic field is applied, the plasma flows along the applied field, filling the torus. Increasing the applied magnetic field seems to aid plasma formation - the peak density increases and the density gradient becomes steeper. Above a threshold magnetic field, the plasma develops low-frequency density oscillations due to probable excitation of flute modes in the plasma.

  13. Effect of soaking and microwave pre-treatment of cowpea seeds on ...

    African Journals Online (AJOL)

    This study was carried out to determine the effect of soaking and microwave energy pre-treatments on the cooking time, anti-nutritional factors and proximate composition of cowpea seeds. Seeds were soaked (6 h) and exposed to microwaves for 2 and 5 min followed by oven-drying (48 ± 2 o C) to obtain a uniform moisture ...

  14. Effect of precooking and polyphosphate treatment on the quality of microwave cooked catfish fillets

    Science.gov (United States)

    In the US market place there are many examples of precooked poultry products designed to be reheated in a microwave oven and, to a lesser extent, fish products such as tilapia. However, few US catfish products are designed to be microwave cooked or reheated. The first objective of this study was t...

  15. 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

  16. Dielectric Study in the Microwave Range for Ceramic Composites Based on Sr2CoNbO6 and TiO2 Mixtures

    Science.gov (United States)

    de Morais, J. E. V.; de Oliveira, R. G. M.; de Castro, A. J. N.; Sales, J. C.; Silva, M. A. S.; Goes, J. C.; Costa, M. M.; Sombra, A. S. B.

    2017-08-01

    In this work, we fabricated ceramic composites based on the composite matrix Sr2CoNbO6 (SCNO)-TiO2. The SCNO was synthesized by solid-state reaction, and x-ray diffraction was used for the structural characterization of this synthesis. We measured the dielectric properties in the microwave range by using the Hakki-Coleman method, as well as the thermal stability of these composites in this frequency range. We inserted TiO2 in an SCNO ceramic matrix in order to improve the thermal stability of SCNO. The cylindrical dielectric resonators were fabricated using concentrations of 5 wt.%, 10 wt.%, 20 wt.%, 40 wt.%, 60 wt.%, and 80 wt.%. The insertion of TiO2 improved the thermal stability, dielectric loss, and permittivity of the SCNO-based ceramic. These ceramic composites were evaluated as dielectric resonator antenna, and the performance of these materials presented a reflection coefficient below -10 dB, gain above 2.5 dBi, and efficiency above 60%.

  17. Measurements of complex permittivity of microwave substrates in the 20 to 300 K temperature range from 26.5 to 40.0 GHz

    Science.gov (United States)

    Miranda, Felix A.; Gordon, William L.; Heinen, Vernon O.; Ebihara, Ben T.; Bhasin, Kul B.

    1990-01-01

    A knowledge of the dielectric properties of microwve substrates at low temperatures is useful in the design of superconducting microwave circuits. Results are reported for a study of the complex permittivity of sapphire (Al2O3), magnesium oxide (MgO), silicon oxide (SiO2), lanthanum aluminate (LaAlO3), and zirconium oxide (ZrO2), in the 20 to 300 Kelvin temperature range, at frequencies from 26.5 to 40.0 GHz. The values of the real and imaginary parts of the complex permittivity were obtained from the scattering parameters, which were measured using an HP-8510 automatic network analyzer. For these measurements, the samples were mounted on the cold head of a helium gas closed cycle refrigerator, in a specially designated vacuum chamber. An arrangement of wave guides, with mica windows, was used to connect the cooling system to the network analyzer. A decrease in the value of the real part of the complex permittivity of these substrates, with decreasing temperature, was observed. For MgO and Al2O3, the decrease from room temperature to 20 K was of 7 and 15 percent, respectively. For LaAlO3, it decreased by 14 percent, for ZrO2 by 15 percent, and for SiO2 by 2 percent, in the above mentioned temperature range.

  18. 29 CFR 1926.1129 - Coke oven emissions.

    Science.gov (United States)

    2010-07-01

    ... oven emissions. Note: The requirements applicable to construction work under this section are identical... 29 Labor 8 2010-07-01 2010-07-01 false Coke oven emissions. 1926.1129 Section 1926.1129 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR...

  19. Strength of Geopolymer Cement Curing at Ambient Temperature by Non-Oven Curing Approaches: An Overview

    Science.gov (United States)

    Wattanachai, Pitiwat; Suwan, Teewara

    2017-06-01

    At the present day, a concept of environmentally friendly construction materials has been intensively studying to reduce the amount of releasing greenhouse gases. Geopolymer is one of the cementitious binders which can be produced by utilising pozzolanic wastes (e.g. fly ash or furnace slag) and also receiving much more attention as a low-CO2 emission material. However, to achieve excellent mechanical properties, heat curing process is needed to apply to geopolymer cement in a range of temperature around 40 to 90°C. To consume less oven-curing energy and be more convenience in practical work, the study on geopolymer curing at ambient temperature (around 20 to 25°C) is therefore widely investigated. In this paper, a core review of factors and approaches for non-oven curing geopolymer has been summarised. The performance, in term of strength, of each non-oven curing method, is also presented and analysed. The main aim of this review paper is to gather the latest study of ambient temperature curing geopolymer and to enlarge a feasibility of non-oven curing geopolymer development. Also, to extend the directions of research work, some approaches or techniques can be combined or applied to the specific properties for in-field applications and embankment stabilization by using soil-cement column.

  20. Experimentos didáticos envolvendo radiação microondas Microwave-assisted experiments for undergraduate courses

    Directory of Open Access Journals (Sweden)

    Fabiana Rosini

    2004-12-01

    Full Text Available Theoretical and practical aspects of the use of microwave-assisted strategies in chemistry are introduced for students using simple and safe experiments employing a domestic oven. Three procedures are proposed for evaluating the distribution of microwave radiation inside the microwave oven cavity: (1 variation of the volume of marshmallows; (2 drying of filter paper wetted with Co(II solution, and (3 variation of water temperature, after microwave-assisted heating. These experiments establish the position with the highest incidence of microwave radiation in the oven cavity, which was chosen for the synthesis of salicylic acid acetate. This synthesis was performed in 5 min of heating and the yield was around 85%. All experiments can be carried out in a 4 h lab-session using low-cost instrumentation.

  1. Report on the first period of operation of the Arobin oven in Me 958

    Energy Technology Data Exchange (ETDEWEB)

    Jagemann, W.; Herbert

    1944-03-27

    Experiences during the first seven months of industrial-scale operation are described. The chemical reactor used for producing the Arobin (aromatic gasoline) had a diameter of 500 mm and a capacity of 880 liters of activated aluminum silicate-molybdic acid catalyst in trays. The oven was fitted with 4 entry ports for cool-gas input for controlling the temperature because of the exothermic reaction (340 cal/kg starting material), and it was preceded by a gas preheater to raise the starting material to about 385/sup 0/C for entry into the oven. Throughput and oven temperature were adjusted to suit the supply of starting material and to maintain the amount of material converted in each pass through the oven at 50% (with the rest of the material being separated out by distillation and recycled into the oven again). Throughput varied from 550 liters/hr to 800 liters/hr, and the cool-gas input was used to regulate the oven temperature within a range of from 425/sup 0/C to 440/sup 0/C in order to maintain the conversion range at 50%. Most operational problems seemed to stem from the need to shut down the operation intermittently and quickly because of air attack. Those shutdowns led to premature coking-up and loss of activity of the catalyst. After that, the rate of conversion could no longer be maintained at 50%, even by more extreme variations of throughput and temperature, until the oven was shut down for a change of catalyst. Another problem which arose was a defect in the distillation column which allowed some low-boiling-point materials to recycle unnecessarily through the system, thus being over-processed and lowering the recovery of aromatic compounds somewhat. During the entire seven months of operation, the yield had averaged 73%, with 14% losses to hydrocarbon gases (some of which were recovered as fuel gas), 8% losses as residues of predistillation, and 5% losses through escape of gases. Properties of products were very similar to those predicted by

  2. Influence of Coking Pressure and Oven Age on Chamber Wall Displacement and Coke Pushing Force

    National Research Council Canada - National Science Library

    Nakagawa, Tomoyuki; Kubota, Yukihiro; Arima, Takashi; Fukuda, Koichi; Kato, Kenji; Awa, Yasuhiko; Sugiura, Masato; Mitsugi, Kenji; Okanishi, Kazuya; Sugiyama, Isao

    2011-01-01

    .... The wall displacement increased in proportion to the internal gas pressure of plastic layer at oven center, and the displacement at superannuated oven per maximum gas pressure was larger than the one at sturdy oven. The pushing force...

  3. Microwave synthesis and actuation of shape memory polycaprolactone foams with high speed

    Science.gov (United States)

    Zhang, Fenghua; Zhou, Tianyang; Liu, Yanju; Leng, Jinsong

    2015-06-01

    Microwave technology is a highly effective approach to fast and uniform heating. This article investigates that the microwave heating as a novel method is used to rapidly foam and actuate biocompatible and biodegradable shape memory crosslinked-polycaprolactone (c-PCL) foams. The optical microscope proves that the resulting c-PCL foams have homogenous pore structure. Mechanical behavior and shape memory performance of c-PCL foams are investigated by static materials testing. Shape recovery ratio is approximately 100% and the whole recovery process takes only 98 s when trigged by microwave. Due to the unique principle of microwave heating, the recovery speed of c-PCL foams in microwave oven is several times faster than that in hot water and electric oven. Hence compared to the traditional heating methods, microwave is expected to bring more advantages to modern industry and scientific research in the field of smart materials and structures.

  4. Precipitable water and surface humidity over global oceans from special sensor microwave imager and European Center for Medium Range Weather Forecasts

    Science.gov (United States)

    Liu, W. T.; Tang, Wenqing; Wentz, Frank J.

    1992-01-01

    Global fields of precipitable water W from the special sensor microwave imager were compared with those from the European Center for Medium Range Weather Forecasts (ECMWF) model. They agree over most ocean areas; both data sets capture the two annual cycles examined and the interannual anomalies during an ENSO episode. They show significant differences in the dry air masses over the eastern tropical-subtropical oceans, particularly in the Southern Hemisphere. In these regions, comparisons with radiosonde data indicate that overestimation by the ECMWF model accounts for a large part of the differences. As a check on the W differences, surface-level specific humidity Q derived from W, using a statistical relation, was compared with Q from the ECMWF model. The differences in Q were found to be consistent with the differences in W, indirectly validating the Q-W relation. In both W and Q, SSMI was able to discern clearly the equatorial extension of the tongues of dry air in the eastern tropical ocean, while both ECMWF and climatological fields have reduced spatial gradients and weaker intensity.

  5. Optimization of resistant starch formation from high amylose corn starch by microwave irradiation treatments and characterization of starch preparations.

    Science.gov (United States)

    Mutlu, Selime; Kahraman, Kevser; Öztürk, Serpil

    2017-02-01

    The effects of microwave irradiation on resistant starch (RS) formation and functional properties in high-amylose corn starch, Hylon VII, by applying microwave-storing cycles and drying processes were investigated. The Response Surface Methodology (RSM) was used to optimize the reaction conditions, microwave time (2-4min) and power (20-100%), for RS formation. The starch:water (1:10) mixtures were cooked and autoclaved and then different microwave-storing cycles and drying (oven or freeze drying) processes were applied. The RS contents of the samples increased with increasing microwave-storing cycle. The highest RS (43.4%) was obtained by oven drying after 3 cycles of microwave treatment at 20% power for 2min. The F, p (<0.05) and R2 values indicated that the selected models were consistent. Linear equations were obtained for oven-dried samples applied by 1 and 3 cycles of microwave with regression coefficients of 0.65 and 0.62, respectively. Quadratic equation was obtained for freeze-dried samples applied by 3 cycles of microwave with a regression coefficient of 0.83. The solubility, water binding capacity (WBC) and RVA viscosity values of the microwave applied samples were higher than those of native Hylon VII. The WBC and viscosity values of the freeze-dried samples were higher than those of the oven-dried ones. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. New approach for the removal of metal ions from water: adsorption onto aquatic plants and microwave reaction for the fabrication of nanometals.

    Science.gov (United States)

    Chefetz, B; Sominski, L; Pinchas, M; Ginsburg, T; Elmachliy, S; Tel-Or, E; Gedanken, A

    2005-08-18

    We adsorb heavy metal ions such as Ag(+), Pb(2+), and Ru(3+) onto an aquatic plant and convert the adsorbed ions to the corresponding nanometallic particles by the polyol reaction carried out in a microwave oven.

  7. Microwave-assisted addition of azomethines to isatoic anhydride

    Indian Academy of Sciences (India)

    TECS

    handicap in measuring the temperature of reaction, possibility of explosion, are some of the main de- fects of microwave oven reactions.10 However, rotat- ing the reaction platform that averages the field can decrease the inhomogeneity of the field. The tem- perature can be measured by taking out the sample at interval as ...

  8. Smelting Magnesium Metal using a Microwave Pidgeon Method

    National Research Council Canada - National Science Library

    Yuji Wada; Satoshi Fujii; Eiichi Suzuki; Masato M Maitani; Shuntaro Tsubaki; Satoshi Chonan; Miho Fukui; Naomi Inazu

    2017-01-01

    ... oven to produce a practical amount of pure Mg metal. This microwave Pidgeon process with an antenna configuration made it possible to produce Mg with an energy consumption of 58.6 GJ/t, corresponding to a 68.6% reduction when compared to the conventional method.

  9. Microwave Mapping Demonstration Using the Thermochromic Cobalt Chloride Equilibrium

    Science.gov (United States)

    Nguyen, Vu D.; Birdwhistell, Kurt R.

    2014-01-01

    An update to the thermochromic cobalt(II) chloride equilibrium demonstration is described. Filter paper that has been saturated with aqueous cobalt(II) chloride is heated for seconds in a microwave oven, producing a color change. The resulting pink and blue map is used to colorfully demonstrate Le Châtelier's principle and to illuminate the…

  10. 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.

  11. Drying Characteristics and Product Quality of Lemon Slices Dried with Hot Air Circulation Oven and Hybrid Heatpump Dryers

    Directory of Open Access Journals (Sweden)

    Yong Hong Lee

    2014-12-01

    Full Text Available In this research, drying characteristics and product quality of Coulomb-force-assisted heatpump and oven dried lemon slices were studied. Lemon slices with 3 mm thickness each, were dried using oven and Coulomb-force-assisted-heatpump dryer with and without auxiliary heater at different drying conditions. It was found that the drying rate of the lemon slices dried by all drying methods showed only falling rate states, which indicates the drying kinetics were controlled by internal moisture diffusion. Oven drying of lemon slices at 60°C showed the highest drying rate among all, followed by oven dried slices at 50°C, Coulomb-force-heater-assisted-heatpump (CF-HT-HP dried slices at 31°C, Coulomb-force-assisted-heatpump (CF-HP dried slices at 22°C, oven dried slices at 40°C and heatpump dried slices at 22°C. The average effective moisture diffusivity value for the slices dried with these drying methods was found in the range of 16.2 to 63.8´10-4 mm2min-1. In terms of quality assessment, CF-HP dried lemon slices retained the highest amount of Vitamin C as compared to the lemon slices dried by other drying methods. However, it retained relatively lower amount of total phenolic content (TPC as compared to oven dried products. Among of all, CF-HP drying method produced dried lemon slices with the highest Vitamin C (6.74 mg AA / g dry weight whereas oven dried lemon slices at 50°C preserved most of the TPC in the dried slices, which recorded as 13.76 mg GA / g dry weight.

  12. RESOLVE OVEN Field Demonstration Unit for Lunar Resource Extraction

    Science.gov (United States)

    Paz, Aaron; Oryshchyn, Lara; Jensen, Scott; Sanders, Gerald B.; Lee, Kris; Reddington, Mike

    2013-01-01

    The Oxygen and Volatile Extraction Node (OVEN) is a subsystem within the Regolith & Environment Science and Oxygen & Lunar Volatile Extraction (RESOLVE) project. The purpose of the OVEN subsystem is to release volatiles from lunar regolith and extract oxygen by means of a hydrogen reduction reaction. The complete process includes receiving, weighing, sealing, heating, and disposing of core sample segments while transferring all gaseous contents to the Lunar Advanced Volatile Analysis (LAVA) subsystem. This document will discuss the design and performance of the OVEN Field Demonstration Unit (FDU), which participated in the 2012 RESOLVE field demonstration.

  13. consideration of can drying ovens using ahp tecnique

    Directory of Open Access Journals (Sweden)

    Hüseyin Pehlivan

    2013-08-01

    Full Text Available In this study, the selection of drying ovens for can gaskets is made at a production plant of tin cans. Among the available three drying oven types, i.e. horizontal, vertical and induction, the optimum type is determined for purchase with the objective of the best suiting the needs of the can production plant. Analytic Hierarchy Process (AHP is employed, and the importance of the critical and dominant criteria is determined. In this way, the optimum type of the drying oven is identified. Results are discussed and summarized based on the current practices used in the tin can production industry.

  14. Microwave and Man—The Direct and Indirect Hazards, and the Precautions

    Science.gov (United States)

    Merckel, Charles

    1972-01-01

    Microwave-radar is a form of electromagnetic energy with potential hazards to human health and safety. Its lethal and non-lethal harmful effects have been demonstrated in experimental animals. Lethal effects upon humans from exposure to microwave have not been proved. Alleged non-lethal effects have been limited primarily to cataractogenesis. Increasing use of microwave commercially in communications and domestically, as in micro-ovens, increases the hazard of exposure to microwave. Increasing use of devices which are at risk from microwave, such as implanted cardiac pacemakers and metal surgical appliances and electronic monitoring devices in operating rooms and clinics, present increasing environmental hazards. PMID:5039801

  15. Microwave-Enhanced Organic Syntheses for the Undergraduate Laboratory: Diels-Alder Cycloaddition, Wittig Reaction, and Williamson Ether Synthesis

    Science.gov (United States)

    Baar, Marsha R.; Falcone, Danielle; Gordon, Christopher

    2010-01-01

    Microwave heating enhanced the rate of three reactions typically performed in our undergraduate organic chemistry laboratory: a Diels-Alder cycloaddition, a Wittig salt formation, and a Williamson ether synthesis. Ninety-minute refluxes were shortened to 10 min using a laboratory-grade microwave oven. In addition, yields improved for the Wittig…

  16. A dedicated electric oven for characterization of thermoresistive polymer nanocomposites

    Directory of Open Access Journals (Sweden)

    M. Cen-Puc

    2016-08-01

    Full Text Available The construction, characterization and control of an electric oven dedicated to the study of thermoresistive polymer nanocomposites is presented. The oven is designed with a heating plate capable of reaching 300 °C with a resolution of 0.3 °C and an area of uniform temperature of 3.8 cm × 2.5 cm. The temperature is regulated by means of a discrete proportional–integral–derivative controller. A heat transfer model comprising three coupled non-linear differential equations is proposed to predict the thermal profiles of the oven during heating and cooling, which are experimentally verified. The oven is used for thermoresistive characterization of polymer nanocomposites manufactured from a polysulfone polymer and multiwall carbon nanotubes.

  17. No-Oven, No-Autoclave, Composite Processing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Cornerstone Research Group Inc. (CRG) proposes to continue the efforts from the 2010 NASA SBIR Phase I topic X5.03, "No-Oven, No-Autoclave (NONA) Composite...

  18. No-Oven, No-Autoclave, Composite Processing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Large, single-piece composite structures for NASA launch vehicles are currently very expensive or impossible to fabricate partly because of the capital (ovens,...

  19. Design of Solar Ovens for Use in the Developing World

    National Research Council Canada - National Science Library

    Rachel Martin; Timothy Bond; John Erickson; Morgan Rog; Cyprienne Crowley; Robert Hutchins; Grayson Fahrner; Kay Lai; Avi Guter; Jack Steiner; Melissa Wrolstad

    2006-01-01

    The main objective of the Cornell Solar Oven Team is to help communities in the developing world design solar cookers appropriate for their specific cultural, social, economic, and environmental conditions...

  20. Synthesis and characterization of CaBi 4Ti 4O 15 thin films annealed by microwave and conventional furnaces

    Science.gov (United States)

    Simões, A. Z.; Riccardi, C. S.; Ramírez, M. A.; Cavalcante, L. S.; Longo, E.; Varela, J. A.

    2007-08-01

    CaBi 4Ti 4O 15 thin films were deposited by the polymeric precursor method and crystallized in a domestic microwave oven and conventional furnace. The films obtained for microwave energy are well-adhered, homogeneous and with good specularity when treated at 700 °C for 10 min. The microstructure and the structure of the films can be tuned by adjusting the crystallization conditions. When microwave oven is employed, the films presented bigger grains with mean grain size around 80 nm. For comparison, films were also prepared by the conventional furnace at 700 °C for 2 h.

  1. 40 CFR 63.302 - Standards for by-product coke oven batteries.

    Science.gov (United States)

    2010-07-01

    ... batteries. 63.302 Section 63.302 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... National Emission Standards for Coke Oven Batteries § 63.302 Standards for by-product coke oven batteries... oven emissions from each affected existing by-product coke oven battery that exceed any of the...

  2. Pecan walnut (Carya illinoinensis (Wangenh.) K. Koch) oil quality and phenolic compounds as affected by microwave and conventional roasting.

    Science.gov (United States)

    Juhaimi, Fahad Al; Özcan, Mehmet Musa; Uslu, Nurhan; Doğu, Süleyman

    2017-12-01

    In this study, the effects of conventional and microwave roasting on phenolic compounds, free acidity, peroxide value, fatty acid composition and tocopherol content of pecan walnut kernel and oil was investigated. The oil content of pecan kernels was 73.78% for microwave oven roasted at 720 W and 73.56% for conventional oven roasted at 110 °C. The highest free fatty acid content (0.50%) and the lowest peroxide value (2.48 meq O2/kg) were observed during microwave roasting at 720 W. The fatty acid profiles and tocopherol contents of pecan kernel oils did not show significant differences compared to raw samples. Roasting process in microwave oven at 720 W caused the reduction of some phenolic compounds, while the content of gallic acid exhibited a significant increase.

  3. Controlled Microwave Irradiation for the Synthesis of YBa 2Cu 3O7-x Superconductors

    Science.gov (United States)

    Naitoh, Katsuyuki; Matsuse, Tokihiro

    1999-07-01

    For synthesizing a high-quality YBa2Cu3O7-xsuperconductor using a domestic microwave oven without any post-heattreatment, the power and time of microwave irradiation are controlled bymonitoring continuously the temperature of the microwave-heated sample.The temperature is measured by means of a metal-sheathed chromel-alumelthermocouple which is installed in the oven in the proper way. Theconditions of the sample inside the oven are almost the same as thesample environment proposed by Kato et al. [Jpn. J. Appl. Phys. 36 (1997) L1291]. The maximum monitoring temperature wherecrystal growth occurs rapidly for a high-quality YBa2Cu3O7-xsuperconductor is shown to be about 500°C which is much lowerthan the maximum heating temperature in the conventional method.

  4. Studies of ZrO{sub 2}-Y{sub 2}O{sub 3} ceramics properties sintered in conventional and microwave oven; Estudos das propriedades de ceramicas de ZrO{sub 2}-Y{sub 2}O{sub 3} sinterizadas em forno convencional de microondas

    Energy Technology Data Exchange (ETDEWEB)

    Gelfuso, M.V.; Capistrano, D.; Thomazini, D., E-mail: virginia@unifor.b [Universidade de Fortaleza (UNIFOR), CE (Brazil); Grzebielucka, E.C.; Chinelatto, A.L.; Chinelatto, A.S.A. [Universidade Estadual de Ponta Grossa (DEMa/UFPG), PR (Brazil). Dept. de Engenharia de Materiais

    2009-07-01

    The ceramic materials processing with nano grain size has developed materials with new properties or improves some of its existing properties. To obtain ceramics with nano grain size, besides that to obtaining nanometric powders, a major goal is to keep the grains size after sintering. Contributing in this line of research, this study aimed to sinter zirconia-Yttria powders through two processes: conventional and microwave sintering. Zirconia stabilized with Yttria powders were obtained by chemical route based on Pechini method. Cylindrical samples were sintered between 1300 to 1500 deg C between 10 and 40 minutes. The samples were characterized by Xray diffraction, Scanning Electron Microscopy and apparent density. It was observed that the final microstructure is influenced by both methods of sintering as the curve of firing used. (author)

  5. Model Stirrer Based on a Multi-Material Turntable for Microwave Processing Materials

    Science.gov (United States)

    Ye, Jinghua; Hong, Tao; Wu, Yuanyuan; Wu, Li; Liao, Yinhong; Zhu, Huacheng; Yang, Yang; Huang, Kama

    2017-01-01

    Microwaves have been widely used in the treatment of materials, such as heating, drying, and sterilization. However, the heating in the commonly used microwave applicators is usually uneven. In this paper, a novel multi-material turntable structure is creatively proposed to improve the temperature uniformity in microwave ovens. Three customized turntables consisting of polyethylene (PE) and alumina, PE and aluminum, and alumina and aluminum are, respectively, utilized in a domestic microwave oven in simulation. During the heating process, the processed material is placed on a fixed Teflon bracket which covers the constantly rotating turntable. Experiments are conducted to measure the surface and point temperatures using an infrared thermal imaging camera and optical fibers. Simulated results are compared qualitatively with the measured ones, which verifies the simulated models. Compared with the turntables consisting of a single material, a 26%–47% increase in temperature uniformity from adapting the multi-material turntable can be observed for the microwave-processed materials. PMID:28772457

  6. PET based nanocomposite films for microwave packaging applications

    Science.gov (United States)

    Galdi, M. R.; Olivieri, R.; Liguori, L.; Albanese, D.; Di Matteo, M.; Di Maio, L.

    2015-12-01

    In recent years, changes in life standards have promoted the diffusion of Ready to Cook (RTC) and Ready to Eat (RTE) products for microwave ovens. However, the main limits in microwave (MW) ovens usage are often related to the proper choice of packaging materials suitable for such technology. In fact, packages for microwaveable RTC and RTE foods should ensure adequate preservation of the product before cooking/heating such as high barriers to gases and aromas and adequate control of water vapor transmission. In addition, microwaveable packaging material must be transparent to MW, thermally stable and resistant to the mechanical stress induced by the accumulation in the head space of volatile substances produced during the cooking. Polymeric materials are good candidates for microwaveable packaging thanks to their transparency to MW. In the last years a great interest is devoted to developing innovative solution based on the use of additives or systems that act as susceptors or heating enhancers for improving the characteristics of polymers in cooking/heating in MW ovens. The present work was focused on the production and characterization of nanocomposite copolyester based films suitable for microwaveable food packaging applications. The matrices selected consist in two PET copolymers modified with carbon black (ULTRA STD) and with titanium oxide (ULTRA NA). Nanocomposite co-extruded multilayer films were produced using different percentages (0%, 2% and 4%wt/wt) of Cloisite 20A (C20A). Films were analyzed for evaluating the effect of nanofiller on the morphology and barrier properties. Moreover, to verify the effectiveness of the designed systems in reducing the cooking times of meat products, MW heating tests were carried out on pork meat hamburgers in MW oven at varying supplied powers. The cooking tests have pointed out that the selected matrices are efficient in reducing cooking times and that even low concentration of C20A acts as heating enhancers of PET.

  7. PET based nanocomposite films for microwave packaging applications

    Energy Technology Data Exchange (ETDEWEB)

    Galdi, M. R., E-mail: mrgaldi@unisa.it; Olivieri, R.; Liguori, L.; Albanese, D., E-mail: dalbanese@unisa.it; Di Matteo, M.; Di Maio, L., E-mail: ldimaio@unisa.it [Industrial Engineering Department, University of Salerno, Via Giovanni Paolo II 132, 84084 Fisciano (Italy)

    2015-12-17

    In recent years, changes in life standards have promoted the diffusion of Ready to Cook (RTC) and Ready to Eat (RTE) products for microwave ovens. However, the main limits in microwave (MW) ovens usage are often related to the proper choice of packaging materials suitable for such technology. In fact, packages for microwaveable RTC and RTE foods should ensure adequate preservation of the product before cooking/heating such as high barriers to gases and aromas and adequate control of water vapor transmission. In addition, microwaveable packaging material must be transparent to MW, thermally stable and resistant to the mechanical stress induced by the accumulation in the head space of volatile substances produced during the cooking. Polymeric materials are good candidates for microwaveable packaging thanks to their transparency to MW. In the last years a great interest is devoted to developing innovative solution based on the use of additives or systems that act as susceptors or heating enhancers for improving the characteristics of polymers in cooking/heating in MW ovens. The present work was focused on the production and characterization of nanocomposite copolyester based films suitable for microwaveable food packaging applications. The matrices selected consist in two PET copolymers modified with carbon black (ULTRA STD) and with titanium oxide (ULTRA NA). Nanocomposite co-extruded multilayer films were produced using different percentages (0%, 2% and 4%wt/wt) of Cloisite 20A (C20A). Films were analyzed for evaluating the effect of nanofiller on the morphology and barrier properties. Moreover, to verify the effectiveness of the designed systems in reducing the cooking times of meat products, MW heating tests were carried out on pork meat hamburgers in MW oven at varying supplied powers. The cooking tests have pointed out that the selected matrices are efficient in reducing cooking times and that even low concentration of C20A acts as heating enhancers of PET.

  8. Methods of microwave fixation for microscopy. A review of research and clinical applications: 1970-1992.

    Science.gov (United States)

    Login, G R; Dvorak, A M

    1994-01-01

    Microwave fixation methods are important because excellent preservation of both cell structure and antigenicity can be attained several orders of magnitude faster than by routine chemical fixation methods. Fast and ultrafast microwave fixation have yielded significant logistic advantages over another fast fixation approach-rapid freezing at liquid helium temperatures. For example, specimens used for microwave fixation can be as large as 1 cm3 and cells can remain in suspension. We review in detail both qualitative and quantitative morphologic results obtained by using microwave fixation in sample preparation. We provide tables of biological molecules that are preserved in a variety of human and animal tissues by various microwave fixation methods for histochemistry, immunohistochemistry, cytochemistry, immunocytochemistry, and affinity labelling studies. Limitations of large cavity (e.g., household) microwave ovens often result in irreproducible fixation results. We present calibration and standardization protocols for microwave fixation in large cavity microwave ovens that emphasize a) localization of oven hot spots (i.e., high power) using a neon bulb array, b) magnetron warm-up, c) the use of a water load, d) the use of an agar-saline-Giemsa model to predict the uniformity of irradiation in small samples, e) the use of specimen containers with one dimension less than 1.5 cm, and f) fast specimen handling to prevent conductive heating artifacts after irradiation. Although microwave ovens are commonplace their unique applications in the laboratory environment require special safety considerations, which are reviewed. Advances in microwave technology are providing new means to study the structure-function relationships of cellular and biochemical activities.

  9. Actual application of hot repairing technology to operating coke oven

    Energy Technology Data Exchange (ETDEWEB)

    Ohtani, Susumu; Ito, Hidekuni; Numazawa, Makoto; Yamazaki, Takao; Narita, Yuji; Kondo, Toshio

    1993-01-01

    In Wakayama Steel Works, the coke ovens have been operating for 23 [approximately] 25 years, and many over-aged parts can be seen. However the investment for the construction of a new coke oven is so huge that the maximum prolongation of the existing coke ovens life becomes very important. In the Wakayama Steel Works, it is thought that the coking chamber repairing technology can be the key to that prolongation. While, repairing the coking chamber, the area near the wall head can be observed by the naked eye and repaired using conventional methods, such a welding repairment by metal oxidation heat, partial chamber wall brick re-laying in the hot stage. However, these repairing methods are limited to the area near the wall head, and successful repair methods for the central portion of chamber wall have not, heretofore, been found. In the Wakayama Steel Works, the development of a new welding repairing machine for the central portion of the chamber wall was started and the actual repairing machine has been completed with practical use tests on operating coke ovens. This repairing machine has the following characteristic; (1) Repair of the central portion of ovens under high temperature (over 1,000 C); (2) Capability to seal narrow cracks or open brick joints and to smooth out brick roughness into a flat surface; (3) High working efficiency (max. welding capacity [equals] 30K g/h); (4) Compact and fully automatic operation with a high level of man/machine control interface; and (5) No disturbance of coke oven operation and no cooling of the chamber wall. In this paper, the outline of the actual hot repairing machine and its application results in the Wakayama operating coke ovens are reported.

  10. Tissue shrinkage in microwave ablation of liver: an ex vivo predictive model.

    Science.gov (United States)

    Amabile, Claudio; Farina, Laura; Lopresto, Vanni; Pinto, Rosanna; Cassarino, Simone; Tosoratti, Nevio; Goldberg, S Nahum; Cavagnaro, Marta

    2017-02-01

    The aim of this study was to develop a predictive model of the shrinkage of liver tissues in microwave ablation. Thirty-seven cuboid specimens of ex vivo bovine liver of size ranging from 2 cm to 8 cm were heated exploiting different techniques: 1) using a microwave oven (2.45 GHz) operated at 420 W, 500 W and 700 W for 8 to 20 min, achieving complete carbonisation of the specimens, 2) using a radiofrequency ablation apparatus (450 kHz) operated at 70 W for a time ranging from 6 to 7.5 min obtaining white coagulation of the specimens, and 3) using a microwave (2.45 GHz) ablation apparatus operated at 60 W for 10 min. Measurements of specimen dimensions, carbonised and coagulated regions were performed using a ruler with an accuracy of 1 mm. Based on the results of the first two experiments a predictive model for the contraction of liver tissue from microwave ablation was constructed and compared to the result of the third experiment. For carbonised tissue, a linear contraction of 31 ± 6% was obtained independently of the heating source, power and operation time. Radiofrequency experiments determined that the average percentage linear contraction of white coagulated tissue was 12 ± 5%. The average accuracy of our model was determined to be 3 mm (5%). The proposed model allows the prediction of the shrinkage of liver tissues upon microwave ablation given the extension of the carbonised and coagulated zones. This may be useful in helping to predict whether sufficient tissue volume is ablated in clinical practice.

  11. Synthesis of 3-substituted 5-arylidene-1-methyl-2-Thiohydantoins under microwave irradiation

    DEFF Research Database (Denmark)

    Khodair, Ahmed I.; Nielsen, John

    2002-01-01

    A mono-modal microwave oven was used to expedite the synthesis of small libraries of 3-substituted 1-methyl-2-thiohydantoins and 3-substituted 5-arylidene-1-methyl-2-thiohydantoins. In comparison with the traditional reflux methods, similar or higher yields were obtained.......A mono-modal microwave oven was used to expedite the synthesis of small libraries of 3-substituted 1-methyl-2-thiohydantoins and 3-substituted 5-arylidene-1-methyl-2-thiohydantoins. In comparison with the traditional reflux methods, similar or higher yields were obtained....

  12. Synthesis of 3-substituted 5-arylidene-1-methyl-2-thiohydantoins under microwave irradiation

    DEFF Research Database (Denmark)

    Khodari, A.I.; Nielsen, John

    2002-01-01

    A mono-modal microwave oven was used to expedite the synthesis of small libraries of 3-substituted 1-methyl-2-thiohydantoins and 3-substituted 5-arylidene-1-methyl-2-thiohydantoins. In comparison with the traditional reflux methods, similar or higher yields were obtained.......A mono-modal microwave oven was used to expedite the synthesis of small libraries of 3-substituted 1-methyl-2-thiohydantoins and 3-substituted 5-arylidene-1-methyl-2-thiohydantoins. In comparison with the traditional reflux methods, similar or higher yields were obtained....

  13. MODIFIKASI ASAM SUKSINAT - GELOMBANG PENDEK UNTUK\tPRODUKSI TAPIOKA SUKSINAT Succinic Acid-Microwave Modification to Produce Succinic Tapioca

    Directory of Open Access Journals (Sweden)

    Heny Herawati

    2012-05-01

    Full Text Available Indonesia as tropical country has great cassava potency. The great chance of cassava product development could be increased its added value through modified tapioca processing. One of modified starch that could be implemented as a food additive is succinic starch. The tapioca succinilation processed through combination process of reacting tapioca with succinic acid and microwave treatment. The research method was conducted by factorial design with 3 factors: substrate concentration (30 %, 40 %, succinic acid concentration (1 %, 3 %, 5 %, and drying method (oven and microwave. Succinic tapioca was analyzed both physical and chemical characteristics, while optimal product was fur- ther analyzed for nutrition contents and surface microstructure using SEM. Succinic acid and microwave modification influenced to the physical and chemical succinic tapioca, except ash content. The highest substitution degree value was 0.929 which was obtained by combination of substrate concentration 40 %, succinic acid added 5 % and microwave processed. The change of granule size was not significant, just the distribution among granule correlated with the tapi- oca modification. The succinic tapioca granule size ranged 5.35 µm until 17.20 µm with average 11.15 µm. Succinic tapioca characteristic hopefully could be advanced food implementation. ABSTRAK Indonesia merupakan negara tropis yang memiliki potensi produksi ubi kayu yang cukup besar. Peluang pengem- bangan produk berbasis ubi kayu di Indonesia masih cukup besar diantaranya yaitu peningkatan nilai tambah ubi kayu melalui proses modifikasi tapioka. Salah satu potensi pati termodifikasi yang dapat dipergunakan untuk bahan tambahan makanan yaitu pati suksinat. Pada penelitian ini proses suksinilasi tapioka dilakukan dengan cara mereak- sikan asam suksinat yang dikombinasikan dengan mempergunakan microwave. Metodologi penelitian yang dilakukan menggunakan rancangan faktorial dengan 3 faktor, yaitu konsentrasi

  14. A Wireless Portable High Temperature Data Monitor for Tunnel Ovens

    Directory of Open Access Journals (Sweden)

    Ricardo Mayo Bayón

    2014-08-01

    Full Text Available Tunnel ovens are widely used in the food industry to produce biscuits and pastries. In order to obtain a high quality product, it is very important to control the heat transferred to each piece of dough during baking. This paper proposes an innovative, non-distorting, low cost wireless temperature measurement system, called “eBiscuit”, which, due to its size, format and location in the metal rack conveyor belt in the oven, is able to measure the temperature a real biscuit experience while baking. The temperature conditions inside the oven are over 200 °C for several minutes, which could damage the “eBiscuit” electronics. This paper compares several thermal insulating materials that can be used in order to avoid exceeding the maximum operational conditions (80 °C in the interior of the “eBiscuit. The data registered is then transmitted to a base station where information can be processed to obtain an oven model. The experimental results with real tunnel ovens confirm its good performance, which allows detecting production anomalies early on.

  15. Discrete transistor measuring and matching using a solid core oven.

    Science.gov (United States)

    Inkinen, M; Mäkelä, K; Vuorela, T; Palovuori, K

    2013-03-01

    This paper presents transistor measurements done at a constant temperature. The aim in this research was to develop a reliable and repeatable method for measuring and searching transistor pairs with similar parameters, as in certain applications it is advantageous to use transistors from the same production batch due to the significant variability in batches from different manufacturers. Transistor manufacturing methods are well established, but due to the large variability in tolerance, not even transistors from the same manufacturing batch have identical properties. Transistors' electrical properties are also strongly temperature-dependent. Therefore, when measuring transistor properties, the temperature must be kept constant. For the measurement process, a solid-core oven providing stable temperature was implemented. In the oven, the base-to-emitter voltage (VBE) and DC-current gain (β) of 32 transistors could be measured simultaneously. The oven's temperature was controlled with a programmable thermostat, which allowed accurate constant temperature operation. The oven is formed by a large metal block with an individual chamber for each transistor to be measured. Isolation of individual transistors and the highly thermally conductive metal core structure prevent thermal coupling between transistors. The oven enables repeatable measurements, and thus measurements between different batches are comparable. In this research study, the properties of over 5000 transistors were measured and the variance of the aforementioned properties was analyzed.

  16. [Characteristics of particulate matter pollution in coke oven plant].

    Science.gov (United States)

    Deng, Hua-xin; Zhang, Wang-zhen; Huang, Kun; He, Yun-feng; Li, Xiao-hai; Kuang, Dan; Lin, Da-feng; Zhang, Xiao-min; Wu, Tang-chun

    2012-12-01

    To explore the characteristics of particulate matter pollution in coke oven plant, so as to provide scientific data for establishing occupational exposure limits for coke oven emissions. Concentrations of CO, SO₂, BSM, BTEX (concentrations of benzene, toluene and xylene were determined in this study), PM₁₀, PM₂.₅, 16 selected PAHs in PM₁₀ and PM₂.₅ were determined in the work environment of a coke oven plant in Wuhan. The work environment was divided into the adjunct area, the bottom of, the side of and the top of coke oven. The concentrations of CO, SO₂, BSM, BETX, PM₁₀, PM₂.₅, PAHs in PM₁₀ and PM₂.₅ were significantly related to working environmental categories, respectively, and were increasing as the adjunct area work environments were not significantly different in one-way ANOVA (P > 0.05). The distribution of aromatic rings and the concentrations of total benzo[a] pyrene equivalents in PM₁₀ and PM₂.₅ were not statistically different between work environments. The concentrations of particulate matter was related with other contents of coke oven emissions in coke work environment, and the contents and types of PAHs in PM₁₀ and PM₂.₅ were similar.

  17. Conventional, microwave, and ultrasound sequential extractions for the fractionation of metals in sediments within the Petrochemical Industry, Serbia.

    Science.gov (United States)

    Relić, Dubravka; Dorđević, Dragana; Sakan, Sanja; Anđelković, Ivan; Pantelić, Ana; Stanković, Ratomir; Popović, Aleksandar

    2013-09-01

    In this paper, the main objective was fractionation of Cd, Cu, Ni, Pb, Zn, Ca, Fe, and K in certificate material and sediment samples gathered from and around the Petrochemical Industry using the conventional, microwave and ultrasonic sequential extraction. Microwave oven and ultrasound bath were used as an energy source for achieving faster extraction. Additional heating and boiling of samples were avoided by using lower power and shorter time for microwave and ultrasound extraction. Precision and accuracy of procedure were evaluated by using certificate material (BCR701). Acceptable accuracy of metals (87.0-111.3 %) was achieved for all three-step sequential of conventional extraction protocol. An accuracy of the fourth step has been verified with two certificate materials: BCR143R and 146R. The range of total extracted metal concentrations from sediments was similar for all three extraction techniques. A significant high percentage of Cd, Cu, and Zn were obtained after extraction of the exchangeable and acid soluble sediment fraction. Principal component analysis of values obtained after determination of risk assessment code using conventional and ultrasound sequential extraction show similarity of these values. Accuracy, recovery, and risk assessment code values imply that ultrasound sequential extraction is a more suitable, accelerated sequential extraction procedure (30 min per extraction step) than microwave extraction in applied conditions.

  18. Evaluation of microwave irradiation for analysis of carbonyl sulfide, carbon disulfide, cyanogen, ethyl formate, methyl bromide, sulfuryl fluoride, propylene oxide, and phosphine in hay.

    Science.gov (United States)

    Ren, Yonglin; Mahon, Daphne

    2007-01-10

    Fumigant residues in hay were "extracted" by microwave irradiation. Hay, in gastight glass flasks, was placed in a domestic microwave oven, and fumigants were released into the headspace by microwave irradiation. Power settings for maximum release of fumigants were determined for carbonyl sulfide (COS), carbon disulfide (CS(2)), cyanogen (C(2)N(2)), ethyl formate (EF), methyl bromide (CH(3)Br), sulfuryl fluoride (SF), propylene oxide (PPO), and phosphine (PH(3)). Recoveries of fortified samples were >91% for COS, CS(2), CH(3)Br, SF, PPO, and PH(3) and >76% for C(2)N(2) and EF. Completeness of extraction was assessed from the amount of fumigant retained by the microwaved hay. This amount was determined from further microwave irradiation and was always small (microwave method is rapid and solvent-free. However, care is required in selecting the appropriate power setting. The safety implications of heating sealed flasks in microwave ovens should be noted.

  19. An Integrated Expert Controller for the Oven Temperature Control System

    Directory of Open Access Journals (Sweden)

    Nagabhushana KATTE

    2011-03-01

    Full Text Available Paper presents a methodology for design of integrated fuzzy logic based an expert controller and its implementation for a real time oven temperature control system. Integrated expert controller (IEC is composed by cascading fuzzy logic controller with improved PID controller. Wherein, fuzzy controller evaluates the supplemental control actions and PID evaluates the final control actions. Temperature measurement of the oven with a precision of 16-bits is achieved through Pt100, instrumentation amplifier, and A/D converter and fuzzy plus PID computed control actions are given to the actuator via D/A converter (16-bits and PWM generator. Paper experimentally demonstrated the performance of IEC for oven temperature control application. The performance indexes of the system are presented in a comparative fashion with the conventional PID and expert controllers. Control algorithms are developed using C language.

  20. Process to manufacture effervescent tablets: air forced oven melt granulation.

    Science.gov (United States)

    Yanze, F M; Duru, C; Jacob, M

    2000-12-01

    In the present study we apply melt granulation in an air forced oven, called "are forced oven melt granulation" to the single-stage manufacture of effervescent granules consisting of anhydrous citric acid (43.2%) and sodium bicarbonate (56.8%) in order to make tablets. This study established that process parameters such as concentration of PEG 6000, residence time in the air forced oven, fineness of PEG 6000, fineness of the initial effervescent mix and efficiency of two lubricants markedly influenced several granule and tablet characteristics. The granules ready to be compressed into tablets were stable for 7 days at 60% RH/18 degrees C. It is a dry, simple, rapid, effective, economical, reproducible process particularly well suited to the manufacture of effervescent granules which are easily compressed into effervescent tablets. Of all the formulations tested, only formulations B2 and E2 melt granulated for 30 minutes gave tablets which had optimum compression characteristics without processing problems during compression.

  1. Microwave sterilization of nitrous oxide nasal hoods contaminated with virus

    Energy Technology Data Exchange (ETDEWEB)

    Young, S.K.; Graves, D.C.; Rohrer, M.D.; Bulard, R.A.

    1985-12-01

    Although there exists a desire to eliminate the possibility of cross-infection from microbial contaminated nitrous oxide nasal hoods, effective and practical methods of sterilization in a dental office are unsatisfactory. Microwaves have been used to sterilize certain contaminated dental instruments without damage. In this study nasal hoods contaminated with rhinovirus, parainfluenza virus, adenovirus, and herpes simplex virus were sterilized in a modified microwave oven. Ninety-five percent of the virus activity was destroyed after 1 minute of exposure of the contaminated nasal hoods to microwaves. By the end of 4 minutes, complete inactivation of all four viruses was found. Repeated exposure of the nasal hoods to microwaves resulted in no damage to their texture and flexibility. Microwave sterilization may potentially provide a simple and practical method of sterilizing nitrous oxide anesthesia equipment in a dental or medical practice.

  2. Microwave sterilization of nitrous oxide nasal hoods contaminated with virus.

    Science.gov (United States)

    Young, S K; Graves, D C; Rohrer, M D; Bulard, R A

    1985-12-01

    Although there exists a desire to eliminate the possibility of cross-infection from microbial contaminated nitrous oxide nasal hoods, effective and practical methods of sterilization in a dental office are unsatisfactory. Microwaves have been used to sterilize certain contaminated dental instruments without damage. In this study nasal hoods contaminated with rhinovirus, parainfluenza virus, adenovirus, and herpes simplex virus were sterilized in a modified microwave oven. Ninety-five percent of the virus activity was destroyed after 1 minute of exposure of the contaminated nasal hoods to microwaves. By the end of 4 minutes, complete inactivation of all four viruses was found. Repeated exposure of the nasal hoods to microwaves resulted in no damage to their texture and flexibility. Microwave sterilization may potentially provide a simple and practical method of sterilizing nitrous oxide anesthesia equipment in a dental or medical practice.

  3. Structural and electrical study of calcium phosphate obtained by a microwave radiation assisted procedure

    Energy Technology Data Exchange (ETDEWEB)

    Silva, C.C. [I3N Group and Physics Department, Aveiro University, Campus Universitario de Santiago, 3810-193, Aveiro (Portugal); Telecommunications and Materials Science and Engineering Laboratory (LOCEM), Physics Department, Federal University of Ceara, Campus do Pici, Postal Code 6030, 60455-760, Fortaleza-Ceara (Brazil); Graca, M.P.F. [I3N Group and Physics Department, Aveiro University, Campus Universitario de Santiago, 3810-193, Aveiro (Portugal); Sombra, A.S.B., E-mail: sombra@fisica.ufc.b [Telecommunications and Materials Science and Engineering Laboratory (LOCEM), Physics Department, Federal University of Ceara, Campus do Pici, Postal Code 6030, 60455-760, Fortaleza-Ceara (Brazil); Valente, M.A. [I3N Group and Physics Department, Aveiro University, Campus Universitario de Santiago, 3810-193, Aveiro (Portugal)

    2009-05-01

    The hydroxyapatite (Ca{sub 10}(PO{sub 4}){sub 6} (OH){sub 2}-HAP) is the main mineral constituent of teeth and bones with excellent biocompatibility with hard and muscle tissues. This material exhibits several problems of handling and preparation, which can be minimized by mixing the HAP with a suitable binder. In order to improve the phase structure, morphology and the dielectric properties, nanocrystalline hydroxyapatite was prepared by a microwave assisted solid-state reaction technique from Ca(OH){sub 2} and CaHPO{sub 4} powders. After milling the mixture was submitted to microwave radiation in a domestic microwave oven (f=2.45 GHz-1 kW) during 15 and 30 min at 1000, 1100 and 1200 deg. C. The samples were analyzed by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), EDS (energy dispersive spectroscopy), FT-IR spectroscopy. The dielectric properties were measured in the frequency range 1 Hz-30 MHz at several temperatures (250-350 K). The dielectric study in function of frequency, at 300 K, was made using the Modulus formalism (M*=1/epsilon*) and a distribution of relaxation times was observed.

  4. Optimization of the coke-oven activated sludge plants

    Energy Technology Data Exchange (ETDEWEB)

    Raizer Neto, Ernesto [Santa Catarina Univ., Florianopolis, SC (Brazil); Colin, Francois [Institut de Recherches Hydrologiques, 54 - Nancy (France); Prost, Christian [Laboratoire de Sciences de Genie Chimique, Nancy (France)

    1993-12-31

    In the coke-oven activated sludge plants one of the greatest problems of malfunction is due to inffluent variability. The composition and, or, concentration variations of the inffluent substrate, which can cause an unstable system, are function of the pollutant load. Nevertheless, the knowledge of the kinetic biodegradation of the coke-oven effluent represents the limiting factor to develop an effective biological treatment. This work describes a computational model of the biological treatment which was elaborated and validated from continuous pilot scale experiments and calibrated by comparing its predictions to the pilot experiment`s results. 12 refs., 9 figs., 3 tabs.

  5. Testing of the Burns-Milwaukee`s Sun Oven

    Energy Technology Data Exchange (ETDEWEB)

    Moss, T.A.

    1997-03-01

    A Burns-Milwaukee Sun Oven was tested at Sandia`s Solar Thermal Test Facility. It was instrumented with five type K thermocouples to determine warm-up rates when empty and when a pot containing two liters of water was placed inside. It reached inside air temperatures above 160{degrees}C (320{degrees}F). It heated two liters of water from room temperatures to 80{degrees}C, (175{degrees}F), in 75 minutes. Observations were also made on the cooling and reheating rates during a cloud passage. The adverse effects of wind on operation of the solar oven was also noted.

  6. Survival of Listeria monocytogenes, E.coli 0157:H7 and Salmonella spp. on catfish fillets exposed to microwave heating in a continuous mode

    Science.gov (United States)

    Microwave (MW) heating using continuous power output with feedback control and a modified ingredient formulation, may provide better and consistent cooking of foods. Currently, household units with build-in inverter power supply units are available. These new generation microwave ovens provide con...

  7. 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...

  8. Microwave-superheated Vics Vapo Rub: an ocular public health danger.

    Science.gov (United States)

    Fung, Anne E; Oxford, Karen W

    2004-02-01

    To report a case of a microwave-oven superheated petroleum-based liquid causing severe chemical and thermal ocular burns treated successfully with amniotic membrane transplantation. Observational case report. Retrospective review of clinical case. A 77-year-old woman sustained a severe combined chemical and thermal burn from microwave-heated Vicks Vapo-Rub requiring amniotic membrane transplant, with subsequent development of phacomorphic glaucoma, requiring cataract extraction, and bullous keratopathy, requiring penetrating keratoplasty. As microwave oven use becomes more commonplace, the risk of superheating liquids becomes an increasingly significant ocular danger. Continued efforts to educate the public about safe microwave use is necessary. Additionally, amniotic membrane transplantation was found to be effective in managing a combined chemical and thermal ocular burn.

  9. Effect of the incident power on permittivity, losses and tunability of BaSrTiO3 thin films in the microwave frequency range

    Science.gov (United States)

    Nadaud, Kevin; Borderon, Caroline; Renoud, Raphaël; Ghalem, Areski; Crunteanu, Aurelian; Huitema, Laure; Dumas-Bouchiat, Frédéric; Marchet, Pascal; Champeaux, Corinne; Gundel, Hartmut W.

    2017-05-01

    Domain wall motions in ferroelectrics participate to the material's complex permittivity and are responsible for their sensitivity of the dielectric properties to the driving electric field and thus to the incident power at microwave frequencies. In the present study, the dependence of the permittivity, the dielectric losses, and the tunability of Ba2/3Sr1/3TiO3 (BST) thin films on the incident power and on the bias fields is examined at a frequency of 500 MHz. While the domain wall motion participates only slightly to the permittivity (influences the losses due to its very dissipative behavior. As a consequence, the Figure of Merit (FoM, the ratio between tunability and dielectric losses) of the material depends on the applied microwave power. In the present study, a decrease in the FoM from 29 to 21 is observed for an incident power varying from -20 dBm to 5 dBm. When characterizing ferroelectric materials, the incident power has to be considered; moreover, domain wall motion effects should be limited in order to achieve a high FoM and less power sensitivity.

  10. Oven Evaporates Isopropyl Alcohol Without Risk Of Explosion

    Science.gov (United States)

    Morgan, Gene E.; Hoult, William S.

    1996-01-01

    Ordinary convection oven with capacity of 1 ft.(sup3) modified for use in drying objects washed in isopropyl alcohol. Nitrogen-purge equipment and safety interlocks added to prevent explosive ignition of flammable solvent evaporating from object to be dried.

  11. Effect of oven residence time on mechanical properties in ...

    Indian Academy of Sciences (India)

    Simulation studies were conducted using ROTOSIM software to analyze thermal transitions and phase changes during the process. Degree of curing of the polymers was also assessed and correlated with mechanical properties. Experiments were further conducted to obtain favourable oven residence time to obtain highest ...

  12. 29 CFR 1910.1029 - Coke oven emissions.

    Science.gov (United States)

    2010-07-01

    ...) Aspiration systems designed and operated to provide sufficient negative pressure and flow volume to... to determine the controls for the coke battery; (c) A report of the technology considered in meeting... harmful effects of exposure to coke oven emissions. (i) Hygiene facilities and practices—(1) Change rooms...

  13. Construction of an Inexpensive Copper Heat-Pipe Oven

    Science.gov (United States)

    Grove, T. T.; Hockensmith, W. A.; Cheviron, N.; Grieser, W.; Dill, R.; Masters, M. F.

    2009-01-01

    We present a new, low-cost method of building an all copper heat-pipe oven that increases the practicality of this device in advanced undergraduate instructional labs. The construction parts are available at local hardware and plumbing supply stores, and the assembly techniques employed are simple and require no machining. (Contains 1 footnote, 3…

  14. Effect of oven residence time on mechanical properties in ...

    Indian Academy of Sciences (India)

    P L Ramkumar

    Abstract. In rotational moulding of plastics, improving the mechanical properties without sacrificing the processibility is a challenging task. In this paper, an attempt has been made to investigate the effect of oven residence time on the mechanical properties of the rotationally moulded products made using linear low density.

  15. Standard test method for determination of "microwave safe for reheating" for ceramicware

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2006-01-01

    1.1 This test method determines the suitability of ceramicware for use in microwave re-heating applications. Microwave ovens are mainly used for reheating and defrosting frozen foods. Severe thermal conditions can occur while reheating foods. Typical reheating of foods requires one to five min. in the microwave at the highest power settings. Longer periods than five minutes are considered cooking. Cooking test methods and standards are not addressed in this test method. Most ceramicware is minimally absorbing of the microwave energy and will not heat up significantly. Unfortunately there are some products that absorb microwave energy to a greater extent and can become very hot in the microwave and pose a serious hazard. Additionally, the nature of microwave heating introduces radiation in a non-uniform manner producing temperature differentials in the food being cooked as well as the ceramic container holding it. The differential may become great enough to thermal shock the ware and create dangerous condition...

  16. Design and construction of a batch oven for investigation of industrial continuous baking processes

    DEFF Research Database (Denmark)

    Stenby Andresen, Mette; Risum, Jørgen; Adler-Nissen, Jens

    2013-01-01

    A new batch oven has been constructed to mimic industrial convection tunnel ovens for research and development of continuous baking processes. The process parameters (air flow, air temperature, air humidity, height of baking area and the baking band velocity) are therefore highly controllable and....... Experimental work in the new batch oven will increase knowledge of how the environment and baking conditions influence the quality of bakery products in continuous tunnel ovens. © 2013 Wiley Periodicals, Inc....

  17. 40 CFR 63.303 - Standards for nonrecovery coke oven batteries.

    Science.gov (United States)

    2010-07-01

    ... coke oven battery shall meet the work practice standards in paragraphs (c)(1) and (2) of this section... or operator of a new nonrecovery coke oven battery shall meet the emission limitations and work... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Standards for nonrecovery coke oven...

  18. Application of microwave energy in the manufacture of enhanced-quality green tea.

    Science.gov (United States)

    Gulati, Ashu; Rawat, Renu; Singh, Brajinder; Ravindranath, S D

    2003-07-30

    Green tea manufacture was standardized with respect to the inactivation of polyphenol oxidase (PPO), rolling, and drying for quality manufacture. Inactivation of PPO by parching, steaming, microwave heating, and oven heating was monitored in tea shoots. The inactivated shoots were rolled under regimens of high and low pressures and dried by microwave heating, oven heating, or sun-drying; total phenols and catechins were estimated. Parched and sun-dried teas contained the lowest levels of total phenols and catechins, and their infusions were dull in color with a slightly burnt odor. Microwave-inactivated and-dried teas showed the highest levels of total phenols and catechins, and their infusions were bright in color and sweet in taste with a subtle pleasant odor. In steam-inactivated and oven/microwave-dried teas, total phenol and catechin contents were intermediate between parched and sun-dried teas and microwave-inactivated and microwave-dried teas, and their infusions were bright with a umami taste.

  19. Microwave Synthesis of Zinc Hydroxy Sulfate Nanoplates and Zinc Oxide Nanorods in the Classroom

    Science.gov (United States)

    Dziedzic, Rafal M.; Gillian-Daniel, Anne Lynn; Peterson, Greta M.; Martínez-Herna´ndez, Kermin J.

    2014-01-01

    In this hands-on, inquiry-based lab, high school and undergraduate students learn about nanotechnology by synthesizing their own nanoparticles in a single class period. This simple synthesis of zinc oxide nanorods and zinc hydroxy sulfate nanoplates can be done in 15 min using a household microwave oven. Reagent concentration, reaction…

  20. Impact of traditional and microwave roasting on chemical composition of hazelnut cultivar 'Tonda di Giffoni'

    NARCIS (Netherlands)

    Manzo, N.; Troise, A.D.; Fogliano, V.; Pizzolongo, F.; Montefusco, I.; Cirillo, C.; Romano, R.

    2017-01-01

    Roasting is a widespread practice for the preservation of hazelnuts. Because traditional treatments conducted by electrical ovens are associated with high energy costs and production of undesired chemical compounds, roasting based on microwaves has been tested by scientists in recent years as an

  1. Poly(4-vinylphenol) gate insulator with cross-linking using a rapid low-power microwave induction heating scheme for organic thin-film-transistors

    OpenAIRE

    Ching-Lin Fan; Ming-Chi Shang; Mao-Yuan Hsia; Shea-Jue Wang; Bohr-Ran Huang; Win-Der Lee

    2016-01-01

    A Microwave-Induction Heating (MIH) scheme is proposed for the poly(4-vinylphenol) (PVP) gate insulator cross-linking process to replace the traditional oven heating cross-linking process. The cross-linking time is significantly decreased from 1 h to 5 min by heating the metal below the PVP layer using microwave irradiation. The necessary microwave power was substantially reduced to about 50 W by decreasing the chamber pressure. The MIH scheme is a good candidate to replace traditional therma...

  2. 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

  3. 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

  4. Microwave as a rapid cooking method for beef tenderness evaluation.

    Science.gov (United States)

    Silva, Douglas R G; Fernandez, Ludimila C; Torres Filho, Robledo A; Fontes, Paulo R; Ramos, Alcinéia L S; Ramos, Eduardo M

    2017-11-20

    Semitendinosus (ST) muscle steaks were grouped according to three locations (proximal, middle, and distal end), grilled to endpoint temperature of 71C or cooked for 20, 30, 40, 50, or 60 s in a microwave oven (Mw). The location did not affect (p > .05) the cooking loss (CL) or shear force (SF) values. The CL increased (p  .05) from the grill samples. None of the microwaves' SF values were different (p > .05) from the grill values, with treatments Mw30 to Mw50 showing moderate repeatability (R = 0.51-0.60) and Mw30 and Mw60 showing higher correlations (r > .71) with grill values. Cooking beef strips with a microwave is a potential method for tenderness evaluation, but requires additional study to evaluate and optimize this application in different muscles and for comparison to sensorial data. The work was intended to evaluate the possibility of using a microwave oven for cooking meat to be used in objective measurement protocols for meat tenderness and to optimize the conditions for this purpose. The use of a standardized microwave procedure allows a dramatic reduction in analysis time and may reduce error variance due to nonuniform cooking procedures. © 2017 Wiley Periodicals, Inc.

  5. Smelting Magnesium Metal using a Microwave Pidgeon Method

    Science.gov (United States)

    Wada, Yuji; Fujii, Satoshi; Suzuki, Eiichi; Maitani, Masato M.; Tsubaki, Shuntaro; Chonan, Satoshi; Fukui, Miho; Inazu, Naomi

    2017-04-01

    Magnesium (Mg) is a lightweight metal with applications in transportation and sustainable battery technologies, but its current production through ore reduction using the conventional Pidgeon process emits large amounts of CO2 and particulate matter (PM2.5). In this work, a novel Pidgeon process driven by microwaves has been developed to produce Mg metal with less energy consumption and no direct CO2 emission. An antenna structure consisting of dolomite as the Mg source and a ferrosilicon antenna as the reducing material was used to confine microwave energy emitted from a magnetron installed in a microwave oven to produce a practical amount of pure Mg metal. This microwave Pidgeon process with an antenna configuration made it possible to produce Mg with an energy consumption of 58.6 GJ/t, corresponding to a 68.6% reduction when compared to the conventional method.

  6. OVEN PANGGANG SEBAGAI SOLUSI PENGOLAHAN IKAN HIGIENIS DAN RAMAH LINGKUNGAN

    Directory of Open Access Journals (Sweden)

    Nana Kariada Tri Martuti

    2014-02-01

    Full Text Available Fish is a perishable food product, so as to be able to maintain the required quality processing. Processing of roasting fish traditionally done by the fishermen and their families in the region Tambakrejo Village Tanjung Mas Semarang. Roasting fish done by grilled over coconut shell charcoal produces less hygienic products. In addition, the resulting smoke spread into the surrounding environment so that the impact on the health of the toaster and the surrounding community. Traditional way of production capacity of 1.5 Kg of fish once baked, so if grilling fish in large numbers takes a long time. Roasting fish with oven roasted made from galvanized plate is advantageous alternative fish processing and environmentally friendly. Oven roast made in the multilevel system (3 level where each level can accommodate fish from 2 to 2.5 kg of fish slices.

  7. Design and Construction of a Batch Oven for Investigation of Industrial Continuous

    DEFF Research Database (Denmark)

    Stenby, Mette; Nielsen, Brian; Risum, Jørgen

    2011-01-01

    A new batch oven has been designed and build to model baking processes as seen in large scale tunnel ovens. In order to simulate the conditions found in tunnel ovens a number of critical parameters are controllable: The temperature, the humidity and the air velocity. The band movement is simulate...... adjustments are still needed in the batch oven setup, it is clear that the batch oven, with its continuous data collection and high degree of process control will be a very valuable tool in the future work with modelling of baking process and products.......A new batch oven has been designed and build to model baking processes as seen in large scale tunnel ovens. In order to simulate the conditions found in tunnel ovens a number of critical parameters are controllable: The temperature, the humidity and the air velocity. The band movement is simulated...... aspects is a unique feature of this batch oven. Initial experiments of reproducing tunnel oven baking in the batch oven have shown good results, based on comparisons of weight loss, dry matter content and surface colour. The measured quality parameters did not differ significantly. Even though a few...

  8. 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

  9. Reduction of heat consumption in coke oven at Mizushima works

    Energy Technology Data Exchange (ETDEWEB)

    Akizuki, H. (and others)

    1987-07-01

    Measures taken by Kawasaki Steel are outlined: controlled use of waterproof coating in the coal stockyard, coupled with improved drainage; an increase in charge weight through coarser crushing; reductions in soaking time, final coke temperature and waste gas temperature and volume; and thermal insulation coating of oven doors. The resulting overall reduction in heat consumption is c. 70 kcal/kg, to 550-570 kcal/kg.

  10. 10 CFR Appendix I to Subpart B of... - Uniform Test Method for Measuring the Energy Consumption of Conventional Ranges, Conventional...

    Science.gov (United States)

    2010-01-01

    ... (228.6±1.3 mm) in diameter, approximately 3.0 inches (76 mm) high and shall weigh 19±0.1 lbs (8.62±0.05... measuring the electrical energy consumption of conventional ovens and cooking tops shall have a resolution... microwave ovens shall have a resolution of 0.1 watt-hour (0.36 kJ) or less and a maximum error no greater...

  11. Heating behavior and crystal growth mechanism in microwave field.

    Science.gov (United States)

    Yang, Gang; Kong, Yan; Hou, Wenhua; Yan, Qijie

    2005-02-03

    A simple microwave solid-state reactor was designed on the basis of a domestic microwave oven by using graphite powder as heating medium. The heating behavior of the reactor was studied by using an on-line computer to monitor the real-time temperature during irradiation. It was found that the temperature (T) was related to the time (t) and that microwave power depended on the duty cycle (x) of microwave irradiation. Two empirical equations were proposed and could be applied to the similar microwave solid-state reactors. Four inorganic layered materials, LiV(3)O(8), KNb(3)O(8), KTiNbO(5), and KSr(2)Nb(3)O(10), were successfully synthesized in the designed reactor at a suitable heating rate and temperature that were fully controlled by the empirical equations. Characterization results of X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Raman spectroscopy, and scanning (SEM) and transmission (TEM) electron microscopy indicated that the phases of samples prepared by traditional and microwave methods were in good agreement; nevertheless, the heating nature and the morphologies of products were quite different. The samples synthesized in the microwave field had crystallographic defects and showed an incompactly stacking structure of nanosheets. Due to the rapid formation of crystallites and different extended growth rate along the crystal axis of the products in microwave field, the crystal growth mechanism of layered metal oxides was not according to that of the traditional method and is briefly discussed.

  12. Optimisation of coal blend and bulk density for coke ovens by vibrocompacting technique non-recovery ovens

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, P.P.; Vinoo, D.S.; Yadav, U.S.; Ghosh, S.; Lal, J.P.N. [J.S.W. Steel Ltd, Bellary (India)

    2007-09-15

    The quality of coke produced in a coke oven depends on the coal blend characteristics and carbonisation conditions. Scarcity of good quality coking coal made it necessary to look for techniques capable of producing superior coke from inferior coals. Precarbonisation techniques improve the bulk density of the coal charge and produce good quality coke from inferior coals. The stamp charging technique, the most effective among them requires finer crushing of coal and higher moisture as binder, both requiring additional energy. JSW Steel has adopted vibrocompaction along with non-recovery ovens for its 1.2 Mtpa coke production. This is a highly ecofriendly coke making process producing excellent quality coke from inferior coals. It increases the bulk density of cake, similar to stamp charging, using compaction in place of stamping. A cake density of 1.10 t m{sup -3} has been achieved using the vibrocompacting technique with optimum moisture and crushing fineness. Coal blend containing up to 35% soft coal and coking coal, having 32% volatile matter have been successfully used to produce a coke with coke strength after reaction >65%, coke reactivity index <25% and M10 <6%. The paper discusses the experience of operating vibrocompaction non-recovery coke ovens.

  13. Electromagnetic and thermal studies of microwave processing of foods

    Science.gov (United States)

    Zhang, Hua

    2000-05-01

    Understanding of the interactions between microwaves and dielectric materials is of great importance in food applications. Such interactions lead to complex variations in heating patterns that are of critical importance in food product and process development. The focus of this research is to study these interactions between food and oven parameters and develop useful relationships between the parameters for practical applications. The approach combines comprehensive numerical modeling with experimentation. Maxwell's equations are solved numerically using a finite element method for a microwave oven system (such as the domestic oven) that includes excitation, waveguide, and cavity and food materials of various size, shape and properties. Temperature effects are included by developing detailed methodology for coupled solution of the Maxwell's equation with energy equation for a solid. Experimental measurements include the use of infrared camera for surface temperature measurements, marker chemicals for time-temperature history effects, and power absorptions obtained indirectly from rate of temperature rise. Heating pattern changes significantly with shape, size and dielectric properties of the food and its placement in the oven. Even more importantly, the heating pattern changes qualitatively with time, due to changes in properties with temperature. Thus, temperatures monitored at a few locations often may not be representative of the overall heating patterns in microwave oven heating. Only comprehensive modeling and/or appropriate experimentation can provide a complete picture. This is critical in applications involving food safety, such as sterilization. Coupled solutions of electromagnetics and heat transfer are found necessary when dielectric properties increase significantly with temperature, as in meats. In applications such as sterilization, where large changes in temperature are needed, coupled models are necessary. Heating non-uniformities due to the effect

  14. 76 FR 65631 - Energy Conservation Program: Test Procedures for Microwave Ovens

    Science.gov (United States)

    2011-10-24

    ... encryption. Postal Mail: Ms. Brenda Edwards, U.S. Department of Energy, Building Technologies Program... submit one signed original paper copy. Hand Delivery/Courier: Ms. Brenda Edwards, U.S. Department of... cooking, and initial and final temperatures, as well as the racks or plates used to hold the food load...

  15. 75 FR 42579 - Energy Conservation Program for Consumer Products: Test Procedure for Microwave Ovens; Repeal of...

    Science.gov (United States)

    2010-07-22

    ... Residential Dishwashers, Dehumidifiers, and Cooking Products and Commercial Clothes Washers. Available online... annual gas energy consumption for any natural gas usage, in British thermal units (Btu's) per year, times...

  16. POPAPY : Designing an animated post card transformed by a microwave oven

    OpenAIRE

    Yang, Shang-hua; 稲蔭, 正彦

    2012-01-01

    Paper is a material that can be easily obtained. However, there currently does not exist any skill or technology that allows people who do not have any technological background to animate paper crafts. Therefore, many people who are not technologically-inclined cannot experience the enjoyment that animated paper craft brings. In this research, an animated post card called "POPAPY" is designed. POPAPY is a post card that will transform into a pop-up card with a different shape after being heat...

  17. 77 FR 33106 - Energy Conservation Program: Test Procedure for Microwave Ovens

    Science.gov (United States)

    2012-06-05

    ...; Individual chicken's physical activity; Genetics; and Methods of breeding and raising chickens from farm to... test method for potential amendments to the DOE test procedure. Table 2 presents the key differences..., including cooking efficiency and annual energy consumption. ] Table 2--Key Differences Between IEC Standard...

  18. A new two-stage approach for predicting the soil water characteristic from saturation to oven-dryness

    DEFF Research Database (Denmark)

    Karup Jensen, Dan; Tuller, Markus; de Jonge, Lis Wollesen

    2015-01-01

    The soil water characteristic (SWC) is one of the most important properties required for understanding plant-soil relationships and is crucial for modeling gas and water flow in soils. Measuring the SWC is laborious, and until now the dry-region soil water retention has commonly been excluded due...... with clay and organic carbon contents ranging from 0.01 to 0.52 kg kg-1 and 0 to 0.07 kg kg-1, respectively, were used for the model development. Measuring the SWC from saturation to oven-dryness was accomplished with Tempe cells and a water vapor sorption analyzer. The model was subsequently tested...... to slow and inaccurate measurements. Hence, models applied to predict the SWC consequently exclude the dry region and are often only applicable for specific soil textural classifications. The present study proposes a new two-step approach to prediction of the continuous SWC from saturation to oven dryness...

  19. Blends of ground tire rubber devulcanized by microwaves/HDPE - Part A: influence of devulcanization process

    Directory of Open Access Journals (Sweden)

    Fabiula Danielli Bastos de Sousa

    2015-06-01

    Full Text Available AbstractThe main objective of this work is the study of the influence of microwaves devulcanization of the elastomeric phase on dynamically revulcanized blends based on Ground Tire Rubber (GTR/High Density Polyethylene (HDPE. The devulcanization of the GTR was performed in a system comprised of a conventional microwave oven adapted with a motorized stirring at a constant microwaves power and at various exposure times. The influence of the devulcanization process on the final properties of the blends was evaluated in terms of mechanical, viscoelastic, thermal and rheological properties. The morphology was also studied.

  20. Synthesis of cubic Y zeolite using a pulsed microwave heating system

    Directory of Open Access Journals (Sweden)

    Araújo L.R.G. de

    1999-01-01

    Full Text Available Cubic Y zeolite were successfully synthesized using microwave heating for 18 - 25 min, whereas 10 - 50 h are required by hydrothermal heating technique depending upon the lattice Si/Al ratio. To this end, we used a commercial microwave oven modified in order to provide pulsed microwave pumping on the synthesis mixtures. The obtained samples were analyzed by X-ray diffraction, BET surface area and infrared spectroscopy measurements. As a result, we verify that Y zeolite samples obtained from hydrogels containing low aluminum contents, present a good degree of crystallinity and then can be suitable for using in adsorption and catalysis experiments.

  1. Comparison of Microwave-Assisted and Conventional Hydrodistillation in the Extraction of Essential Oils from Mango (Mangifera indica L.) Flowers

    OpenAIRE

    Hong-Wu Wang; Yan-Qing Liu; Shou-Lian Wei; Zi-Jun Yan; Kuan Lu

    2010-01-01

    Microwave-assisted hydrodistillation (MAHD) is an advanced hydrodistillation (HD) technique, in which a microwave oven is used in the extraction process. MAHD and HD methods have been compared and evaluated for their effectiveness in the isolation of essential oils from fresh mango (Mangifera indica L.) flowers. MAHD offers important advantages over HD in terms of energy savings and extraction time (75 min against 4 h). The composition of the extracted essential oils was investigated by GC-FI...

  2. A microwave approach to the synthesis of certain 4-substituted phenyl-6-phenyl-3-cyano-2-pyridones

    Directory of Open Access Journals (Sweden)

    Marinković Aleksandar

    2014-01-01

    Full Text Available A study of the synthesis of 4-substituted phenyl-6-phenyl-3-cyano-2-pyridones from 2-cyano-3-phenylsubstituted acrylates and acetophenone is presented. 2-Pyridones were obtained using conventional as well as microwave synthesis using solvent and solvent free reactions in domestic and lab microwave ovens. The structure of the obtained pyridones was confirmed by m.p., FT-IR, NMR and UV data. [Projekat Ministarstva nauke Republike Srbije, br. 172013

  3. Nutritional quality of microwave-cooked and pressure-cooked legumes.

    Science.gov (United States)

    Khatoon, Naveeda; Prakash, Jamuna

    2004-09-01

    Eight whole legumes, namely Bengal gram (Cicer arietinum), broad beans (Vicia faba), Cowpea (Vigna catjang), field beans (Dolichos lablab), green gram (Phaseolus aureus Roxb), horse gram (Dolichos biflorus), lentils (Lens esculenta) and French beans (Phaseolus vulgaris), were cooked under pressure or in a microwave oven and were analysed for nutrient composition. Raw legumes served as control. The range of nutrients analysed in 100 g cooked samples were as follows: moisture, 62.8-69.7 g; protein, 14.7-24.3 g; fat, 0.9-5.9 g; ash, 1.7-4.6 g; iron, 3.3-8.6 mg; calcium, 50-209 mg; phosphorus, 249-429 mg; and thiamin, 0.14-0.32 mg. Cooking methods did not affect the nutrient composition of legumes. However, thiamine decreased in cooked samples. Cooking altered the dietary fibre content of some legumes. The mean in vitro protein digestibility of pressure-cooked and microwaved samples was 79.8% and 74.7%, respectively. The in vitro starch and protein digestibility of pressure-cooked samples were higher.

  4. An assessment of the thermal safety of microwave warming of crystalloid fluids.

    Science.gov (United States)

    Lindhoff, G A; MacG Palmer, J H

    2000-03-01

    We performed an in vitro study to determine the thermal safety of a domestic microwave to warm intravenous crystalloid solutions. Five-hundred-millilitre bags of crystalloid, randomly allocated to groups which differed in power setting, timer setting and whether or not agitation was performed after warming, were heated in a microwave oven to a calculated temperature of 39 degrees C. Timer accuracy was checked by stopwatch. Bag temperature was measured using an infrared tympanic temperature probe and fluid temperature was measured with an in-line thermocouple. Mean times measured by stopwatch were higher than set. No in-line temperatures reached 40 degrees C. Wider overall ranges and a higher mean were found with the tympanic probe compared with in-line temperature measurement. There were significant differences between the in-line temperatures of shaken and unshaken bags at each power setting, but not when groups were added together. There was no change in colour or odour of bags or fluid. One bag developed a pinhole leak when the packaging was removed.

  5. Síntese e hidrólise de azalactonas de Erlenmeyer-Plöchl mediadas por radiação micro-ondas em aparelhos doméstico e dedicado: experimentos de química orgânica para a graduação Synthesis and hydrolysis of Erlenmeyer-Plöchl azalactones mediated by microwave radiation in domestic and dedicated ovens: undergraduate organic chemistry experiments

    Directory of Open Access Journals (Sweden)

    Silvio Cunha

    2013-01-01

    Full Text Available This work describes a green chemistry experiment for the synthesis of Erlenmeyer-Plöchl azalactones mediated by microwave irradiation, employing both dedicated and domestic equipment. Hippuric acid was reacted with equimolar amounts of benzaldehyde, p-chloro-benzaldehyde or p-N,N-dimethyl-benzaldehyde in acetic anhydride as the solvent. Acid hydrolysis of obtained 4-benzylidene-2-phenyloxazol-5(4H-one under microwave and convectional heating afforded Z-α-(benzoylaminocinnamic acid at a 51-61.5% yield. The UV-Vis molecular spectra of 4-benzylidene-2-phenyloxazol-5(4H-one and 4-(4'-N,N-dimethylbenzylidene-2-phenyloxazol-5(4H-one were obtained in ethanol, CH2Cl2 and DMSO and bathochromic shift was observed for the latter azalactone.

  6. Circular Bioassay Platforms for Applications in Microwave-Accelerated Techniques.

    Science.gov (United States)

    Mohammed, Muzaffer; Clement, Travis C; Aslan, Kadir

    2014-12-02

    In this paper, we present the design of four different circular bioassay platforms, which are suitable for homogeneous microwave heating, using theoretical calculations (i.e., COMSOL™ multiphysics software). Circular bioassay platforms are constructed from poly(methyl methacrylate) (PMMA) for optical transparency between 400-800 nm, has multiple sample capacity (12, 16, 19 and 21 wells) and modified with silver nanoparticle films (SNFs) to be used in microwave-accelerated bioassays (MABs). In addition, a small monomode microwave cavity, which can be operated with an external microwave generator (100 W), for use with the bioassay platforms in MABs is also developed. Our design parameters for the circular bioassay platforms and monomode microwave cavity during microwave heating were: (i) temperature profiles, (ii) electric field distributions, (iii) location of the circular bioassay platforms inside the microwave cavity, and (iv) design and number of wells on the circular bioassay platforms. We have also carried out additional simulations to assess the use of circular bioassay platforms in a conventional kitchen microwave oven (e.g., 900 W). Our results show that the location of the circular bioassay platforms in the microwave cavity was predicted to have a significant effect on the homogeneous heating of these platforms. The 21-well circular bioassay platform design in our monomode microwave cavity was predicted to offer a homogeneous heating pattern, where inter-well temperature was observed to be in between 23.72-24.13°C and intra-well temperature difference was less than 0.21°C for 60 seconds of microwave heating, which was also verified experimentally.

  7. Testing of the Sunstove Organization`s Sunstove Solar Oven

    Energy Technology Data Exchange (ETDEWEB)

    Moss, T.A.

    1997-03-01

    A Sunstove Organization`s Sunstove was tested at Sandia`s Solar Thermal Test Facility. It was instrumented with five type K thermocouples to determine warm-up rates when empty and when a pot containing two liters of water was placed inside. It reached inside air temperatures above 115{degrees}C (240{degrees}F). It heated two liters of water from room temperature to 80{degrees}C (175{degrees}F) in about two hours. Observations were made on the cooling and reheating rates during a cloud passage. The adverse effects of wind on the operation of the solar oven were also noted.

  8. Finite element modelling and simulation of free convection heat transfer in solar oven

    Energy Technology Data Exchange (ETDEWEB)

    Sobamowo, M.G.; Ogunmola, B.Y.; Ayerin A.M. [Department of Mechanical Engineering, University of Lagos, Akoka, Lagos (Nigeria)

    2013-07-01

    The use of solar energy for baking, heating or drying represents a sustainable way of solar energy applications with negligible negative effects. Solar oven is an alternative to conventional oven that rely heavily on coal and wood or Electric oven that uses the power from the National grid of which the end users have little or no control. Since the Solar oven uses no fuel and it costs nothing to run, it uses are widely promoted especially in situations where minimum fuel consumption or fire risks are considered highly important. As useful as the Solar Oven proved, it major setback in the area of applications has been its future sustainability. For the use of Solar Oven/Cookers to be sustained in the future, the design and development of solar oven must rely on sound analytical tools. Therefore, this work focused on the design and development of the solar oven. To test the performance of the Small Solar Oven a 5000cm3 beaker of water was put into the Oven and the temperature of the water was found to reach 810C after about 3hrs under an average ambient temperature of 300C. On no load test, the oven reached a maximum temperature of 112oC in 6hrs. In order to carry out the parametric studies and improve the performance of the Solar Oven, Mathematical models were developed and solved by using Characteristics-Based Split (CBS) Finite Element Method. The Model results were compared with the Experimental results and a good agreement was found between the two results.

  9. Survival of Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella spp. on catfish fillets exposed to microwave heating in a continuous mode.

    Science.gov (United States)

    Sheen, Shiowshuh; Huang, Lihan; Sommers, Christopher

    2012-08-01

    Microwave (MW) heating using continuous power output with feedback control and a modified ingredient formulation may provide better and consistent cooking of foods. Currently, household units with build-in inverter power supply units are available. These new generation MW ovens provide continuous, adjustable output and cooking, in contrast to the traditional rectifier-based ovens that rely on the on-off mechanism for control. This study attempted to apply a feedback power control (termed as modified or "smart" MW oven) and phosphate treatment to further improve heating uniformity and enhance food quality and safety. Listeria monocytogenes (Lm, 4-strain cocktail), Escherichia coli O157:H7 (Ec, 5-strain cocktail), and Salmonella spp. (Sal, 6-strain cocktail), surface inoculated onto catfish fillets (75 × 100 × 15 mm; weight 110 g), were heated using the modified MW oven to study the inactivation of the pathogens. The sensitivity of these 3 bacteria to MW heating was in the order of Ec (most), Lm, and Sal (least). Greater than 4 to 5 log CFU reductions of Ec, Lm, or Sal counts on catfish fillet surfaces were inactivated within 2 min of 1250 W MW heating, where the fillet surface temperature increased from 10 to 20 °C to 80 to 90 °C. MW heating caused degradation of catfish fillet texture, which was noticeable as early as 10 to 15 s after the heating started, as evidenced by bumping sounds. Bumping can be significantly reduced by soaking fillets in phosphate solution. However, the results may need verification if applied in different MW ovens and/or with foods positioned away the geometric oven center. This study successfully demonstrated the feasibility of applying MW energy to eliminate foodborne pathogens on fish fillets. The results demonstrated in this report with the "smart" microwave oven design may enhance microwaveable food safety and quality, and therefore promote the microwaveable food business. © 2012 Institute of Food Technologists®

  10. Use of computational fluid dynamics in domestic oven design

    Directory of Open Access Journals (Sweden)

    Mark Fahey

    2008-03-01

    Full Text Available There is an increasing demand, both from customers and regulatory sources, for safer and more energy efficient products. Manufacturers are having to look to their design and development processes to service these demands. Traditional approaches have been to use prototype testing and only delve more deeply into specific aspects of the performance when issues arise. In this work the complex flow within the cooling circuit of the door of a pyrolytic oven is studied. A combination of Computational Fluid Dynamics (CFD and experimental techniques is used. It will be shown that CFD can help with the achievement of an optimal solution, with the understanding of the flow behaviour and that there is a synergy between the numerical and experimental techniques. Using only one of these techniques would limit the understanding of the flow behaviour and could lead to a less than optimal solution to the design problem. This work aims to explore this particular complex industrial fluid flow situation to: understand the flow around the oven door’s cooling circuit  demonstrate the synergy of CFD and experimental work within development of a complex product explore the role of CFD within the product development process.

  11. Photonic filtering of microwave signals in the frequency range of 0.01-20 GHz using a Fabry-Perot filter

    Energy Technology Data Exchange (ETDEWEB)

    Aguayo-Rodriguez, G; Zaldivar-Huerta, I E [Instituto Nacional de Astrofisica, Optica y Electronica (INAOE). Sta. Maria Tonantzintla, Pue. Mexico (Mexico); GarcIa-Juarez, A [Depto. de Investigacion en Fisica, Universidad de Sonora (UNISON) Hermosillo, Son. Mexico (Mexico); Rodriguez-Asomoza, J [Depto. de Ingenieria Electronica, Universidad de las Americas-Puebla (UDLA). San Andres Cholula, Pue. Mexico (Mexico); Larger, L; Courjal, N [Laboratoire d' Optique P. M. Duffieux, UMR 6603 CNRS, Institut des Microtechiques de Franche-Comte, FRW 0067, UFR Sciences et Techniques, Universite de Franche-Comte (UFC), Besancon cedex (France)

    2011-01-01

    We demonstrate experimentally the efficiency of tuning of a photonic filter in the frequency range of 0.01 to 20 GHz. The presented work combines the use of a multimode optical source associated with a dispersive optical fiber to obtain the filtering effect. Tunability effect is achieved by the use of a Fabry-Perot filter that allows altering the spectral characteristics of the optical source. Experimental results are validated by means of numerical simulations. The scheme here proposed has a potential application in the field of optical telecommunications.

  12. Hybrid solar-electric oven construction prototype; Construccion de prototipo de horno hibrido solar-electrico

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez Roman, M. A; Pineda Pinon, J; Arcos Pichardo, A [CICATA, Santiago de Queretaro, Queretaro (Mexico)

    2013-03-15

    The oven construction consists of a solar collector system of cylindrical parabolic type, a heating through electrical resistance and a curing chamber. The warm fluid is air, which is injected into the chamber through forced draft. The temperature required in the system is within a range of 150 to 300 degrees Celsius. [Spanish] La construccion del horno consta de un sistema de captacion solar del tipo cilindrico parabolico, un sistema de calentamiento a traves de resistencias electricas y una camara de curado. El fluido a calentar es aire, el cual es inyectado dentro de la camara a traves de tiro forzado. La temperatura solicitada en el sistema es dentro de un rango de 150 a 300 grados centigrados.

  13. New automated microwave heating process for cooking and pasteurization of microwaveable foods containing raw meats.

    Science.gov (United States)

    Huang, Lihan; Sites, Joseph

    2010-03-01

    A new microwave heating process was developed for cooking microwaveable foods containing raw meats. A commercially available inverter-based microwave oven was modified for pasteurization of mechanically tenderized beef, inoculated with Escherichia coli O157:H7 (approximately 5 log(10) CFU/g) and packaged in a 12-oz CPET tray containing 150-mL de-ionized water. The new microwave heating system was equipped with an infrared sensor and a proportional feedback mechanism to allow temperature controlled microwave heating. A 2-stage heating strategy was adopted to cook the product. In the primary heating stage, the sample surface temperature was increased to an initial temperature set-point (ITSP, 65, 70, 75, or 80 degrees C). In the secondary heating stage, the heating was continued with a small fraction of microwave power. The effect of ITSP, hold time (0 to 3 min), and sample elevation (0, 0.03, and 0.07 m above turntable) on inactivation of E. coli O157:H7 and background microflora was evaluated. It was observed that only a small number (approximately 1.3 logs) of E. coli O157:H7 and background microflora were inactivated in the primary heating stage. The elevation 0.07 m, which was in the proximity of the geometric center of the metal cavity, was more effective in inactivating both E. coli O157:H7 and background microflora. Substantially more bacteria were inactivated in the secondary heating stage. Complete inactivation of E. coli and background microflora was observed with heating at temperatures above 70 degrees C for more than 1 min. This study demonstrated a new approach for ensuring the safety of microwaveable products containing raw meats.

  14. 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.

  15. Microwave Filters

    OpenAIRE

    Zhou, Jiafeng

    2010-01-01

    The general theory of microwave filter design based on lumped-element circuit is described in this chapter. The lowpass prototype filters with Butterworth, Chebyshev and quasielliptic characteristics are synthesized, and the prototype filters are then transformed to bandpass filters by lowpass to bandpass frequency mapping. By using immitance inverters ( J - or K -inverters), the bandpass filters can be realized by the same type of resonators. One design example is given to verify the theory ...

  16. Rapid synthesis of tin oxide nanostructures by microwave-assisted thermal oxidation for sensor applications

    Science.gov (United States)

    Phadungdhitidhada, S.; Ruankham, P.; Gardchareon, A.; Wongratanaphisan, D.; Choopun, S.

    2017-09-01

    In the present work nanostructures of tin oxides were synthesized by a microwave-assisted thermal oxidation. Tin precursor powder was loaded into a cylindrical quartz tube and further radiated in a microwave oven. The as-synthesized products were characterized by scanning electron microscope, transmission electron microscope, and x-ray diffractometer. The results showed that two different morphologies of SnO2 microwires (MWs) and nanoparticles (NPs) were obtained in one minute of microwave radiation under atmospheric ambient. A few tens of the SnO2 MWs with the length of 10-50 µm were found. Some parts of the MWs were decorated with the SnO2 NPs. However, most of the products were SnO2 NPs with the diameter ranging from 30-200 nm. Preparation under loosely closed system lead to mixed phase SnO-SnO2 NPs with diameter of 30-200 nm. The single-phase of SnO2 could be obtained by mixing the Sn precursor powders with CuO2. The products were mostly found to be SnO2 nanowires (NWs) and MWs. The diameter of SnO2 NWs was less than 50 nm. The SnO2 NPs, MWs, and NWs were in the cassiterite rutile structure phase. The SnO NPs was in the tetragonal structure phase. The growth direction of the SnO2 NWs was observed in (1 1 0) and (2 2 1) direction. The ethanol sensor performance of these tin oxide nanostructures showed that the SnO-SnO2 NPs exhibited extremely high sensitivity. Invited talk at 5th Thailand International Nanotechnology Conference (Nano Thailand-2016), 27-29 November 2016, Nakhon Ratchasima, Thailand.

  17. Heat transfer and heating rate of food stuffs in commercial shop ovens

    Indian Academy of Sciences (India)

    The CFD analysis of flow and temperature distribution in heating ovens used in bakery shop, to keep the foodstuffs warm, is attempted using finite element technique. The oven is modelled as a two-dimensional steady state natural convection heat transfer problem. Effects of heater location and total heat input on ...

  18. Microwave sintering of Ag-nanoparticle thin films on a polyimide substrate

    Directory of Open Access Journals (Sweden)

    S. Fujii

    2015-12-01

    Full Text Available Ag-nanoparticle thin films on a polyimide substrate were subjected to microwave sintering by use of a single-mode waveguide applicator. A two-step sintering process was employed. First, at low conductivities of the film, the film sample was placed at the site of the maximum electric field and subjected to microwave irradiation. Second, when the conductivity of the film increased, the film sample was placed at the site of the maximum magnetic field and again subjected to microwave irradiation. The microwave sintering process was completed within 1.5 min, which is significantly lower than the time required for the oven heating process. The resulting conductivity of the film, albeit only 30% of that of the bulk material, was seven times that of a film annealed at the same temperature in a furnace. Scanning electron microscopy images revealed that the nanoparticles underwent both grain necking and grain growth during microwave sintering. In addition, this sintering process was equivalent to the oven heating process performed at a 50 °C higher annealing temperature. An electromagnetic wave simulation and a heat transfer simulation of the microwave sintering process were performed to gain a thorough understanding of the process.

  19. 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

  20. Fuzzy Logic Applied to an Oven Temperature Control System

    Directory of Open Access Journals (Sweden)

    Nagabhushana KATTE

    2011-10-01

    Full Text Available The paper describes the methodology of design and development of fuzzy logic based oven temperature control system. As simple fuzzy logic controller (FLC structure with an efficient realization and a small rule base that can be easily implemented in existing underwater control systems is proposed. The FLC has been designed using bell-shaped membership function for fuzzification, 49 control rules in its rule base and centre of gravity technique for defuzzification. Analog interface card with 16-bits resolution is designed to achieve higher precision in temperature measurement and control. The experimental results of PID and FLC implemented system are drawn for a step input and presented in a comparative fashion. FLC exhibits fast response and it has got sharp rise time and smooth control over conventional PID controller. The paper scrupulously discusses the hardware and software (developed using ‘C’ language features of the system.

  1. Using low porosity refractory materials in coke ovens

    Energy Technology Data Exchange (ETDEWEB)

    Narita, Y.; Sudzuki, T.

    1982-02-19

    Refractory bricks with porosity (KP) of less than or equal to 17 percent, which contain less than 1 percent iron oxide and are resiliant at temperatures of more than 1,000/sup 0/C, are made through caking or electrosmelting of materials with a high aluminum content (chamotte, sillimanite, cordierite, pagodite) and silicon content (magnesial chromite, alumina, magnesite, calcite and zircon). In a refractory material with a seeming porosity of less than or equal to 17 percent the deposition of carbon in the pores is reduced which promotes a constant heat conductivity and strength of the refractory material in the operation of coke ovens. Normally the carbon is formed with the reduction of CO under the catalytic action of iron oxide.

  2. Fast microwave assisted pyrolysis of biomass using microwave absorbent.

    Science.gov (United States)

    Borges, Fernanda Cabral; Du, Zhenyi; Xie, Qinglong; Trierweiler, Jorge Otávio; Cheng, Yanling; Wan, Yiqin; Liu, Yuhuan; Zhu, Rongbi; Lin, Xiangyang; Chen, Paul; Ruan, Roger

    2014-03-01

    A novel concept of fast microwave assisted pyrolysis (fMAP) in the presence of microwave absorbents was presented and examined. Wood sawdust and corn stover were pyrolyzed by means of microwave heating and silicon carbide (SiC) as microwave absorbent. The bio-oil was characterized, and the effects of temperature, feedstock loading, particle sizes, and vacuum degree were analyzed. For wood sawdust, a temperature of 480°C, 50 grit SiC, with 2g/min of biomass feeding, were the optimal conditions, with a maximum bio-oil yield of 65 wt.%. For corn stover, temperatures ranging from 490°C to 560°C, biomass particle sizes from 0.9mm to 1.9mm, and vacuum degree lower than 100mmHg obtained a maximum bio-oil yield of 64 wt.%. This study shows that the use of microwave absorbents for fMAP is feasible and a promising technology to improve the practical values and commercial application outlook of microwave based pyrolysis. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Effect of Oven Types on the Characteristics of Biscuits Made from Refrigerated and Frozen Doughs

    Directory of Open Access Journals (Sweden)

    Ismail Sait Dogan

    2006-01-01

    Full Text Available Characteristics of sugar snap and chocolate chip cookies, and hazelnut biscuits made from refrigerated and frozen dough were studied. Doughs were stored at 4 °C for 6 weeks and at –18 °C for 6 months, respectively. Physical characteristics of the biscuit samples such as spread, baking loss, surface colour and density were determined. Dough colour was not affected by storage time and temperatures. Biscuit characteristics did not change significantly during storage. Spread ratio was significantly lower for the biscuits baked in the gas oven than for the biscuits baked in the electric oven. Biscuit dough can be refrigerated for 6 weeks, and frozen for 6 months. Results also suggest that unique quality differences exist between the two ovens. For sugar snap cookies and hazelnut biscuits the electric oven without air circulation was better, while for chocolate chip cookies gas oven with air circulation was more suitable.

  4. Rapid hydrolysis of proteins and peptides by means of microwave technology and its application to amino acid analysis.

    Science.gov (United States)

    Chen, S T; Chiou, S H; Chu, Y H; Wang, K T

    1987-10-01

    A rapid heating method of hydrolysis by the use of microwave oven has been applied to amino acid analysis of proteins and peptides. This convenient method has been compared with the conventional 6 N HCl hydrolysis at 110 degrees for 24 h. The advantages of this new method are its expedition and the accurate and comparable results as compared to the tedious conventional technique. The method provides a rapid processing of multiple samples within minutes instead of days and inexpensive access to the important data of amino acid compositions of proteins by the commonly used microwave oven. The necessary change in the design of hydrolysis vials and the safety precautions accompanying this novel use of microwave acid-digestion method are also described.

  5. Comparison of microwave-assisted and conventional hydrodistillation in the extraction of essential oils from mango (Mangifera indica L.) flowers.

    Science.gov (United States)

    Wang, Hong-Wu; Liu, Yan-Qing; Wei, Shou-Lian; Yan, Zi-Jun; Lu, Kuan

    2010-10-29

    Microwave-assisted hydrodistillation (MAHD) is an advanced hydrodistillation (HD) technique, in which a microwave oven is used in the extraction process. MAHD and HD methods have been compared and evaluated for their effectiveness in the isolation of essential oils from fresh mango (Mangifera indica L.) flowers. MAHD offers important advantages over HD in terms of energy savings and extraction time (75 min against 4 h). The composition of the extracted essential oils was investigated by GC-FID and GC-MS. Results indicate that the use of microwave irradiation did not adversely influence the composition of the essential oils. MAHD was also found to be a green technology.

  6. [The posibility of usage microwave energy as an alternative method of disinfection for silicone impressions in orthopaedic dentistry].

    Science.gov (United States)

    Nespriad'ko, V P; Shevchuk, V O; Omel'ianenko, M D

    2011-01-01

    In this experimental investigation estimated the effect of microwave disinfection on the alteration of dimensional stability of silicone impressions and gypsum casts poured from them comparing to an invariable parameters of metal die. In this article uncovers the main point of origin, spreading and influence according to the classical theory of electro-magnetic waves (EMW) as an example was used the model M745R Samsung microwave oven. We evaluated possibilities and advantages of use the auxiliary plant for flowing regulation of the power of microwave radiation that calls "microUndaDent". It was designed, developed and installated by us in the department of orthopaedic dentistry.

  7. Applications of Graphene at Microwave Frequencies

    Directory of Open Access Journals (Sweden)

    M. Bozzi

    2015-09-01

    Full Text Available In view to the epochal scenarios that nanotechnology discloses, nano-electronics has the potential to introduce a paradigm shift in electronic systems design similar to that of the transition from vacuum tubes to semiconductor devices. Since low dimensional (1D and 2D nano-structured materials exhibit unprecedented electro-mechanical properties in a wide frequency range, including radio-frequencies (RF, microwave nano-electronics provides an enormous and yet widely undiscovered opportunity for the engineering community. Carbon nano-electronics is one of the main research routes of RF/microwave nano-electronics. In particular, graphene has shown proven results as an emblematic protagonist, and a real solution for a wide variety of microwave electronic devices and circuits. This paper introduces graphene properties in the microwave range, and presents a paradigm of novel graphene-based devices and applications in the microwave/RF frequency range.

  8. Synthesis by Microwaves of Bimetallic Nano-Rhodium-Palladium

    Directory of Open Access Journals (Sweden)

    M. Ugalde

    2013-01-01

    Full Text Available An improved acrylamide sol-gel technique using a microwave oven in order to synthesize bimetallic Rh-Pd particles is reported and discussed. The synthesis of Pd and Rh nanoparticles was carried out separately. The polymerization to form the gel of both Rh and Pd was carried out at 80°C under constant agitations. The method chosen to prepare the Rh and Pd xerogels involved the decomposition of both gels. The process begins by steadily increasing the temperature of the gel inside a microwave oven (from 80°C to 170°C. In order to eliminate the by-products generated during the sol-gel reaction, a heat treatment at a temperature of 1000°C for 2 h in inert atmosphere was carried out. After the heat treatment, the particle size increased from 50 nm to 200 nm, producing the bimetallic Rh-Pd clusters. It can be concluded that the reported microwave-assisted, sol-gel method was able to obtain nano-bimetallic Rh-Pd particles with an average size of 75 nm.

  9. A microwave photonic generator of chaotic and noise signals

    Science.gov (United States)

    Ustinov, A. B.; Kondrashov, A. V.; Kalinikos, B. A.

    2016-04-01

    The transition to chaos in a microwave photonic generator has been experimentally studied for the first time, and the generated broadband chaotic microwave signal has been analyzed. The generator represented a ring circuit with the microwave tract containing a low-pass filter and a microwave amplifier. The optical tract comprised a fiber delay line. The possibility of generating chaotic oscillations with uniform spectral power density in a 3-8 GHz range is demonstrated.

  10. Building a Low Cost Solar Oven: An Opportunity to Teach Thermodynamics

    Science.gov (United States)

    Nogueira, Ana

    2014-03-01

    We suggested building a solar oven using cardboard boxes, glass wool and metal plate as part of a school project permeated by the discussion of physical concepts. The main topics addressed are from the heat and thermodynamics areas, and for these themes we followed the standard books used in high school. We can work in a practical manner with the thermometer, along with the concept of temperature, measuring the temperature of the oven when cooking. To discuss how the oven works, we introduce the concept of heat as an energy flow of a body with a higher temperature to one with lower temperature. Threads as heat capacity and specific heat of a substance are introduced, also discussing the use of glass wool, which function is to prevent heat exchange from the oven's interior with the environment. It is possible to demonstrate the three forms of heat transfer using the solar oven, and how the greenhouse effect is harnessed. One can discuss topics such as electromagnetic radiation, black-body radiation and the Stefan-Boltzmann law. We surveyed the response curve of our oven and an estimate of its total solar energy absorption efficiency. The development of this project allows a good understanding of the operation principles of a solar oven. UNIMONTES.

  11. Acid-catalysed deuterium exchange of aromatic protons. Pt. 3; Accelerated exchange by microwave irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Koeves, G.J. (Centre of Forensic Sciences, Toronto, ON (Canada))

    1994-03-01

    Conventional acid-catalysed [sup 2]H/[sup 1]H exchange in aromatic rings requires long reaction times, high temperatures and pressure. This paper reports that accelerated deuterium exchange can be achieved in a microwave oven. Experiments were carried out on benzodiazepines, tricyclic antidepressants and phenothiazines. The reaction time was decreased from days to minutes, the preparatory work was simpler than with conventional heating and the labelled products were cleaner. (author).

  12. GFAAS determination of selenium in infant formulas using a microwave digestion method.

    Science.gov (United States)

    Alegria, A; Barbera, R; Farré, R; Moreno, A

    1994-01-01

    A method for determining the selenium content of infant formulas is proposed. It includes wet digestion with nitric acid and hydrogen peroxide in medium pressure teflon bombs in a microwave oven and determination by graphite furnace atomic absorption spectrometry (GFAAS). The absence of interferences is checked. Values obtained for the limit of detection (19.4 ng/g), precision (RSD = 2.2%) and accuracy by analysis of a reference material show that the method is reliable.

  13. Electrical properties of the electroceramic composite in the microwave frequency range: Pb(Fe0.5Nb0.5)O3 (PFN)-Cr0.75Fe1.25O3 (CRFO)

    Science.gov (United States)

    Santos, M. R. P.; Freire, F. N. A.; Sohn, R. S. T. M.; Almeida, J. S.; Sancho, E. O.; Costa, A. D. S. B.; Medeiros, A. M. L.; Sombra, A. S. B.

    2008-12-01

    In this paper, a new electroceramic composite [Pb(Fe0.5Nb0.5) O3 (PFN)]Z [Cr0.75Fe1.25O3 (CRFO)]100-Z (Z = 0, 10) is investigated in the microwave (MW) frequency range. The dielectric permittivity and loss in the region of 4-8 GHz (G and H MW bands) were studied. The performance of cylindrical resonator antennas based on CRFO100 and on PFN10 was examined. The experimental and theoretical results of the dielectric resonator antenna (DRA) such as return loss, bandwidth, input impedance and radiation patterns are in good agreement for both composites: PFN10 (10% PFN + 90% CRFO) and CRFO100 (100% CRFO). A numerical validation was made considering an air gap between the dielectric resonator and the metallic conductors. The PFN10 matrix composite PFN10 (10% PFN + 90% CRFO) presents the highest dielectric permittivity (9.9 at 4.44 GHz) and the lowest bandwidth (9.9%). The CRFO100 phase (100% CRFO) presents a dielectric permittivity of 8.35 at 4.67 GHz and a bandwidth of 11.8%. The Hakki-Coleman procedure was also used in this study. The dielectric permittivity of 8.35 (tan δ = 1 × 10-3) at 7.94 GHz was obtained for CRFO100. The PFN10 presents a dielectric permittivity of 10.17 (tan δ = 4.9 × 10-3) at 7.05 GHz. These measurements confirm the possible use of such material for small DRAs.

  14. Synthesis of WC powder through microwave heating of WO3-C mixture

    Science.gov (United States)

    Behnami, Amir Karimzadeh; Hoseinpur, Arman; Sakaki, Masoud; Bafghi, Mohammad Sh.; Yanagisawa, Kazumichi

    2017-02-01

    A simple, easy, and low-cost process for the fabrication of tungsten carbide (WC) powder through microwave heating of WO3-C mixtures was developed. Thermodynamic calculations and experimental investigations were carried out for WO3-C and W-C systems, and a formation mechanism was proposed. In the results, for the synthesis of WC, the use of over stoichiometric amount of C together with a specially assembled experimental setup (which effectively retains heat in the system) is necessary. The WC powder is successfully obtained by heating WO3:5C mixture for 900 s in a domestic microwave oven.

  15. Preliminary comparative studies of Thermus aquaticus resilience to thermal and microwave heat input

    Science.gov (United States)

    Kabza, Konrad; George, Karen; von Meer, Stella; Kargol, Armin

    2008-03-01

    Thermus aquaticus was grown using existing ATCC protocol. Bacteria were cultured in large batches and each batch partitioned into usable 250 mL aliquots. These samples were then tested using identical parallel experiments, one heated with a traditional thermal heat source, while the other was irradiated with a 2.45 GHz conventional microwave oven. Relative growth of the Thermus aquaticus was measured using UV visible spectroscopy at 400 nm. Multiple runs of the same experiments were averaged and the growth data for two modes of energization plotted. A unique low microwave exposure apparatus with a flow-through cell will be described and the entire experimental setup discussed.

  16. 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.

  17. Microwave synthesis of catalyst spinel MnCo 2O 4 for alkaline fuel cell

    Science.gov (United States)

    Nissinen, Terhi; Valo, Taina; Gasik, Michael; Rantanen, Jyri; Lampinen, Markku

    Spinels, AB 2O 4, are promising catalysts for the oxygen reduction reaction in alkaline fuel cells since they have no noble metals and can be prepared by rather simple methods. In this work the spinel MnCo 2O 4 was fabricated from decomposition of salts and subsequent heat treatment in microwave and conventional ovens. The catalytic activity of spinels for the oxygen reduction reaction was examined in alkaline conditions in a specially designed test bed. XRD, SEM, surface area, and carbon content measurements were used to analyze the prepared powders. Spinel was not detected for treatment in a microwave oven at 650 W power without carbon, but in the presence of carbon it was formed at 125 W rapidly (in a few minutes). These spinels have smaller particles and higher specific surface area and they have demonstrated higher catalytic activity for the oxygen reduction reaction than the spinels prepared in a conventional oven. The Microwave technique proved to be a favorable and fast way to prepare catalytically active spinel MnCo 2O 4 for alkaline fuel cells. Tested fuel cells are being adapted for transport applications in vehicles.

  18. Melting of tin using muffle furnace and microwave energy and its characterization

    Science.gov (United States)

    Gouthama, T. R.; Harisha, G.; Manjunatha, Y. R.; Mohana Kumara, S. M.; Srinath, M. S.; Shashank Lingappa, M.

    2016-09-01

    Conventional melting of metals consume significant amount of energy. Furthermore, there are possibilities of material and energy losses along with safety risks. To overcome these inherent disadvantages of conventional melting, a novel approach for melting of bulk tin using microwave energy is presented. In the present work, bulk Tin is melted using a conventional muffle furnace and a domestic multimode microwave oven. As received and as cast metals are characterised. X-Ray Diffraction (XRD) technique is used to analyse the phases present. The average tensile strength of the metal casted using muffle furnace and microwave oven is 44.1982 MPa and 50.2867 MPa respectively. Scanning Electron Microscope (SEM) is made use for the study of fractured surface of the tensile specimen, which reveals the areas of plastic deformation. Microwave processed specimen shows 10% higher tensile strength compared to that processed using muffle furnace. Radiography clearly shows cast specimen free from defects. The average hardness of as received tin is higher compared to casted specimens. However, the average hardness value of microwave processed specimen is 19.28% higher than the specimen processed using muffle furnace.

  19. Model Stirrer Based on a Multi-Material Turntable for Microwave Processing Materials

    Directory of Open Access Journals (Sweden)

    Jinghua Ye

    2017-01-01

    Full Text Available Microwaves have been widely used in the treatment of materials, such as heating, drying, and sterilization. However, the heating in the commonly used microwave applicators is usually uneven. In this paper, a novel multi-material turntable structure is creatively proposed to improve the temperature uniformity in microwave ovens. Three customized turntables consisting of polyethylene (PE and alumina, PE and aluminum, and alumina and aluminum are, respectively, utilized in a domestic microwave oven in simulation. During the heating process, the processed material is placed on a fixed Teflon bracket which covers the constantly rotating turntable. Experiments are conducted to measure the surface and point temperatures using an infrared thermal imaging camera and optical fibers. Simulated results are compared qualitatively with the measured ones, which verifies the simulated models. Compared with the turntables consisting of a single material, a 26%–47% increase in temperature uniformity from adapting the multi-material turntable can be observed for the microwave-processed materials.

  20. Microwave Sterilization and Depyrogenation System

    Science.gov (United States)

    Akse, James R.; Dahl, Roger W.; Wheeler, Richard R., Jr.

    2009-01-01

    at a given flow rate. These technologies can be employed in small-scale systems for efficient production of MGW in the laboratory or in a range of larger systems that meet various industrial requirements. The microwave antennas can also be adapted to selectively sterilize vulnerable connections to ultra-pure water production facilities or biologically vulnerable systems where microorganisms may intrude.

  1. Microwave-Assisted Hydro-Distillation of Essential Oil from Rosemary: Comparison with Traditional Distillation.

    Science.gov (United States)

    Moradi, Sara; Fazlali, Alireza; Hamedi, Hamid

    2018-01-01

    Hydro-distillation (HD) method is a traditional technique which is used in most industrial companies. Microwave-assisted Hydro-distillation (MAHD) is an advanced HD technique utilizing a microwave oven in the extraction process. In this research, MAHD of essential oils from the aerial parts (leaves) of rosemary ( Rosmarinus officinalis L. ) was studied and the results were compared with those of the conventional HD in terms of extraction time, extraction efficiency, chemical composition, quality of the essential oils and cost of the operation. Microwave hydro-distillation was superior in terms of saving energy and extraction time (30 min , compared to 90 min in HD). Chromatography was used for quantity analysis of the essential oils composition. Quality of essential oil improved in MAHD method due to an increase of 17% in oxygenated compounds. Consequently, microwave hydro-distillation can be used as a substitute of traditional hydro-distillation.

  2. Characterization of sponge cake baking in an instrumented pilot oven

    Directory of Open Access Journals (Sweden)

    Alain Sommier

    2012-10-01

    Full Text Available The quality of baked products is the complex, multidimensional result of a recipe, and a controlled heating process to produce the desired final properties such as taste, colour, shape, structure and density. The process of baking a sponge cake in a convective oven at different air temperatures (160-180-220 °C leading to the same loss of mass was considered in this study. A special mould was used which allowed unidirectional heat transfer in the batter. Instrumentation was developed specifically for online measurement of weight loss, height variation and transient temperature profile and pressure in the product. This method was based on measuring heat fluxes (commercial sensors to account for differences in product expansion and colour. In addition, measurement of height with a camera was coupled to the product mass to calculate changes in density over time. Finally, combining this information with more traditional measurements gave a better understanding of heat and mass transfer phenomena occurring during baking.

  3. Impact of Microwave Treatment on Chemical Constituents in Fresh Rhizoma Gastrodiae (Tianma by UPLC-MS Analysis

    Directory of Open Access Journals (Sweden)

    Qimeng Fan

    2014-01-01

    Full Text Available Fresh Rhizoma Gastrodiae (Tianma was processed in a microwave oven at 2450 MHz in order to study the effect on the main chemical component changes taking place during microwave treatment. It was found that microwave affected the chemical composition of Tianma. Seven compounds, including gastrodin, gastrodigenin (p-hydroxybenzylalcohol, p-hydroxybenzaldehyde, vanillyl alcohol, vanillin, adenine, and 5-hydroxymethylfurfural, were identified in this study. As major active compounds, the contents of gastrodin and gastrodigenin in MWT Tianma were both twice as much as those in raw Tianma. Besides, the MS data show that there are still some unidentified compositions in Tianma, and there are also many converted compounds in MWT Tianma, which is worthy of further work. The results have indicated that microwave treated fresh Tianma might be helpful in designing the processing of traditional Chinese medicine and the application of microwave technology in traditional Chinese medicine needs to be researched further in the future.

  4. Microwave materials for wireless applications

    CERN Document Server

    Cruickshank, David B

    2011-01-01

    This practical resource offers you an in-depth, up-to-date understanding of the use of microwave magnetic materials for cutting-edge wireless applications. The book discusses device applications used in wireless infrastructure base stations, point-to-point radio links, and a range of more specialized microwave systems. You find detailed discussions on the attributes of each family of magnetic materials with respect to specific wireless applications. Moreover, the book addresses two of the hottest topics in the field today - insertion loss and intermodulation. This comprehensive reference also

  5. Analysis and numerical simulation research of the heating process in the oven

    Science.gov (United States)

    Chen, Yawei; Lei, Dingyou

    2016-10-01

    How to use the oven to bake delicious food is the most concerned problem of the designers and users of the oven. For this intent, this paper analyzed the heat distribution in the oven based on the basic operation principles and proceeded the data simulation of the temperature distribution on the rack section. Constructing the differential equation model of the temperature distribution changes in the pan when the oven works based on the heat radiation and heat transmission, based on the idea of utilizing cellular automation to simulate heat transfer process, used ANSYS software to proceed the numerical simulation analysis to the rectangular, round-cornered rectangular, elliptical and circular pans and giving out the instantaneous temperature distribution of the corresponding shapes of the pans. The temperature distribution of the rectangular and circular pans proves that the product gets overcooked easily at the corners and edges of rectangular pans but not of a round pan.

  6. Urinary 1-hydroxypyrene and 8-hydroxydeoxyguanosine levels among coke-oven workers for 2 consecutive days.

    Science.gov (United States)

    Nguyen, Thi-To-Uyen; Kawanami, Shoko; Kawai, Kazuaki; Kasai, Hiroshi; Li, Yun-Shan; Inoue, Jinro; Ngoan, Le Tran; Horie, Seichi

    2014-01-01

    This study evaluated the levels of exposure to polycyclic aromatic hydrocarbons (PAHs) and their relationship with oxidative DNA damage among Vietnamese coke-oven workers. We collected urine from 36 coke-oven workers (exposed group) at the beginning and end of the shift on 2 consecutive days. We also collected urine from 78 medical staff (control group). Information was collected by questionnaire about smoking status, drinking habit, and working position. Urinary 1-hydroxypyrene (1-OHP) and 8-hydroxydeoxyguanosine (8-OH-dG) were measured using HPLC. All statistical analyses were performed with SPSS version 19. Urinary 1-OHP was significantly higher in the coke-oven workers than in the control group (poven workers had the highest levels of internal exposure to PAHs, followed by side-oven and then bottom-oven workers (5.41, 4.41 and 1.35 ng/mg creatinine, respectively, at the end of the shift on day 2). Urinary 8-OH-dG was significantly higher in top- and side-oven workers at the end of the shift on day 2 (4.63 and 5.88 ng/mg creatinine, respectively) than in the control group (3.85 ng/mg creatinine). Based on a multi-regression analysis, smoking status had a significant effect on urinary 8-OH-dG (p=0.049). Urinary 1-OHP tended to have a positive correlation with urinary 8-OH-dG (p=0.070). Vietnamese coke-oven workers were exposed to PAHs during their work shift. Urinary 1-OHP exceeded the recommended limit, and elevated oxidative DNA damage occurred in top- and side-oven workers on the second day of work. A tendency for positive correlation was found between urinary 1-OHP and urinary 8-OH-dG.

  7. [Determination of heavy metals for RoHS compliance by ICP-OES spectrometry coupled with microwave extraction system].

    Science.gov (United States)

    Hua, Li; Wu, Yi-Ping; An, Bing; Lai, Xiao-Wei

    2008-11-01

    The harm of heavy metals contained in electronic and electrical equipment (EEE) on environment is of high concern by human. Aiming to handle the great challenge of RoHS compliance, the determinations of trace or ultratrace chromium (Cr), cadmium (Cd), mercury (Hg) and lead (Pb) by inductively coupled plasma optical emission spectrometry (ICP-OES) was performed in the present paper, wherein, microwave extraction technology was used to prepare the sample solutions. In addition, the precision, recovery, repeatability and interference issues of this method were also discussed. The results exhibited that using the microwave extraction system to prepare samples is more quick, lossless, contamination-free in comparison with the conventional extraction methods such as dry ashing, wet-oven extraction etc. By analyzing the recoveries of these four heavy metals over different working time and wavelengths, the good recovery range between 85% and 115% showed that there was only tiny loss or contamination during the process of microwave extraction, sample introduction and ICP detection. Repeatability experiments proved that ICP plasma had a good stability during the working time and the matrix effect was small. Interference was a problem troublesome for atomic absorption spectrometry (AAS), however, the techniques of standard additions or inter-element correction (IEC) method can effectively eliminated the interferences of Ni, As, Fe etc. with the Cd determination. By employing the multi-wavelengths and two correction point methods, the issues of background curve sloping shift and spectra overlap were successfully overcome. Besides, for the determinations of trace heavy metal elements, the relative standard deviation (RSD) was less than 3% and the detection limits were less than 1 microg x L(-10 (3sigma, n = 5) for samples, standard solutions, and standard additions, which proved that ICP-OES has a good precision and high reliability. This provided a reliable technique support

  8. Microwave-assisted synthesis of sensitive silver substrate for surface-enhanced Raman scattering spectroscopy

    Science.gov (United States)

    Xia, Lixin; Wang, Haibo; Wang, Jian; Gong, Ke; Jia, Yi; Zhang, Huili; Sun, Mengtao

    2008-10-01

    A sensitive silver substrate for surface-enhanced Raman scattering (SERS) spectroscopy is synthesized under multimode microwave irradiation. The microwave-assisted synthesis of the SERS-active substrate was carried out in a modified domestic microwave oven of 2450MHz, and the reductive reaction was conducted in a polypropylene container under microwave irradiation with a power of 100W for 5min. Formaldehyde was employed as both the reductant and microwave absorber in the reductive process. The effects of different heating methods (microwave dielectric and conventional) on the properties of the SERS-active substrates were investigated. Samples obtained with 5min of microwave irradiation at a power of 100W have more well-defined edges, corners, and sharper surface features, while the samples synthesized with 1h of conventional heating at 40°C consist primarily of spheroidal nanoparticles. The SERS peak intensity of the ˜1593cm-1 band of 4-mercaptobenzoic acid adsorbed on silver nanoparticles synthesized with 5min of microwave irradiation at a power of 100W is about 30 times greater than when it is adsorbed on samples synthesized with 1h of conventional heating at 40°C. The results of quantum chemical calculations are in good agreement with our experimental data. This method is expected to be utilized for the synthesis of other metal nanostructural materials.

  9. Comparative effect of microwaves and boiling on the denaturation of DNA

    Energy Technology Data Exchange (ETDEWEB)

    Stroop, W.G.; Schaefer, D.C. (Veterans Administration Medical Center, Salt Lake City, UT (USA))

    1989-11-01

    The effect of heat and microwave denaturation of small volumes of double-stranded plasmid DNA has been compared. Samples of intact plasmid DNA had plasmid DNA linearized by digestion with EcoRI were conventionally denatured in a boiling water bath or denatured by 2450 MHz of microwave energy for 0-300 s. Heat denaturation for periods longer than 120 s caused breakdown of linearized plasmid DNA; however, microwave denaturation for 10-300 s caused no apparent degradation of linearized DNA. Breakdown of DNA forms II and III was noted in plasmid DNA subjected to 300 s of either heat or microwave denaturation but breakdown of forms II and III occurred more quickly with heat than with microwave treatment. Microwave treatment was also found to be better than heat to denature 32P-labeled DNA probes subsequently used to detect homologous DNA samples immobilized on nitrocellulose filters. A microwave-treated 32P-labeled DNA probe was able to hybridize to DNA samples 20 times more dilute than a heat-treated 32P-labeled DNA probe. Depending on the form of DNA to be analyzed, these results indicate that small volumes of DNA solutions and radiolabeled DNA probes can be effectively denatured in a conventional microwave oven.

  10. Set-up and first operation of a plasma oven for treatment of low level radioactive wastes

    Directory of Open Access Journals (Sweden)

    Nachtrodt Frederik

    2014-01-01

    Full Text Available An experimental device for plasma treatment of low and intermediate level radioactive waste was built and tested in several design variations. The laboratory device is designed with the intention to study the general effects and difficulties in a plasma incineration set-up for the further future development of a larger scale pilot plant. The key part of the device consists of a novel microwave plasma torch driven by 200 W electric power, and operating at atmospheric pressure. It is a specific design characteristic of the torch that a high peak temperature can be reached with a low power input compared to other plasma torches. Experiments have been carried out to analyze the effect of the plasma on materials typical for operational low-level wastes. In some preliminary cold tests the behavior of stable volatile species e. g., caesium was investigated by TXRF measurements of material collected from the oven walls and the filtered off-gas. The results help in improving and scaling up the existing design and in understanding the effects for a pilot plant, especially for the off-gas collection and treatment.

  11. No-Oven, No-Autoclave Composite Processing

    Science.gov (United States)

    Rauscher, Michael D.

    2015-01-01

    Very large composite structures, such as those used in NASA's Space Launch System, push the boundaries imposed by current autoclaves. New technology is needed to maintain composite performance and free manufacturing engineers from the restraints of curing equipment size limitations. Recent efforts on a Phase II project by Cornerstone Research Group, Inc. (CRG), have advanced the technology and manufacturing readiness levels of a unique two-part epoxy resin system. Designed for room-temperature infusion of a dry carbon preform, the system includes a no-heat-added cure that delivers 350 F composite performance in a matter of hours. This no-oven, no-autoclave (NONA) composite processing eliminates part-size constraints imposed by infrastructure and lowers costs by increasing throughput and reducing capital-specific, process-flow bottlenecks. As a result of the Phase II activity, NONA materials and processes were used to make high-temperature composite tooling suitable for further production of carbon-epoxy laminates and honeycomb/ sandwich-structure composites with an aluminum core. The technology platform involves tooling design, resin infusion processing, composite part design, and resin chemistry. The various technology elements are combined to achieve a fully cured part. The individual elements are not unusual, but they are combined in such a way that enables proper management of the heat generated by the epoxy resin during cure. The result is a self-cured carbon/ epoxy composite part that is mechanically and chemically stable at temperatures up to 350 F. As a result of the successful SBIR effort, CRG has launched NONA Composites as a spinoff subsidiary. The company sells resin to end users, fabricates finished goods for customers, and sells composite tooling made with NONA materials and processes to composite manufacturers.

  12. An introduction to high power microwaves

    Science.gov (United States)

    Benford, James; Swegle, John

    1992-02-01

    The area of high power microwaves has emerged in recent years as a new technology allowing new applications and offering innovative approaches to existing applications. The great leap in microwave power levels has been driven by a mix of sources that either push conventional microwave device physics in new directions or employ altogether new interaction mechanisms. Running counter to the trend in conventional microwave electronics toward miniaturization with solid-state devices intrinsically limited in their peak power capability, high power microwave generation taps the immense power and energy reservoirs of modern intense relativistic electron beam technology. The term high power microwaves (HPM) is used to denote devices that exceed 100 MW in peak power and span the cm- and mm-wave range of frequencies between 1 and 300 GHz. This definition is arbitrary, but does cleanly divide the conventional microwave devices, which do not exceed 100 MW, from a collection of microwave-generating devices that have now reached powers as high as 15 GW.

  13. Parallel processing multitemperature robotic tester and burn-in oven for InGaAsP lasers

    Science.gov (United States)

    Gazier, Michael A.; Leung, Ming; Cremer, Ed; Hess, Dave; Volkmer, Frank

    1994-06-01

    Coolerless lasers meeting Bellcore technical advisory TA-TSY-000983 are needed for access applications. To this end, a parallel processing multi-temperature robotic tester (MTRT) for high volume dc characterization of semiconductor lasers over the temperature range -40 degree(s)C to +85 degree(s)C is presented. The cartridge based system is fully integrated with the device burn-in oven, allowing for automated testing and handling. The robot picks devices from a cartridge and places them in one of seven test pods, each independently temperature controlled and serviced by a stage with a photodetector, movable polarizer, and a fiber. The test pods measure dc, pulsed, polarized and non-polarized L/Is, V/Is, and optical spectrums of the devices at each temperature. The test software is multi- threaded and includes a custom task scheduler and mailbox system. This C software is three- tiered with a user-interface process, a test system process, and a database link process. All test specifications, device specifications, and device data are acquired from and stored back onto a remote database for data analysis and reporting. The database is also accessed via a 4GL user- friendly interface. An independent cartridge-based burn-in performs the automatic current control (ACC) burn-in cycles between tests and integrates into the robotic test system equipment. Together, the robot and the burn-in oven perform all process steps required between the post-bond and final test manufacturing stages.

  14. Spectroscopy of peaks at microwave range for nanostructure SrFe{sub 12}O{sub 19} and NiFe{sub 2}O{sub 4} ferrite particles

    Energy Technology Data Exchange (ETDEWEB)

    Ariaee, Sina, E-mail: sina.ariaee@tabrizu.ac.ir; Mehdipour, Mostafa, E-mail: Mostafa_mehdipour67@yahoo.com; Moradnia, Mina, E-mail: mina.moradnia86@gmail.com

    2017-05-01

    In this paper, (SrFe{sub 12}O{sub 19} and NiFe{sub 2}O{sub 4}) nanostructure ferrite particles were synthesized via the co-precipitation of chloride salts utilizing the sodium hydroxide solution. The resulting precursors were heat-treated at 1100 °C for 4 h. After cooling in the furnace, the ferrite powders were pressed at 0.1 MPa and then sintered at 1200 °C for 4 h. The spectroscopy and characterization of peaks at the microwave range (X-band) for the nanostructure ferrite particles were investigated by the ferromagnetic resonance/transmit-line theories and Reflection Loss (RL) plots. The extracted data from these theoretical and experimental results showed that the natural ferromagnetic resonance can be lead to the narrow peaks and the width of the peaks can be related to the periodic effects. Two kinds of peaks were seen for NiFe{sub 2}O{sub 4} at X-band (8–12 GHz); the narrow peak at (9.8 GHz) was remaining unchanged and consistent while the wide one was shifted from 11 GHz to 8.5 GHz by decreasing the thickness of the samples. These phenomena were also happened for SrFe{sub 12}O{sub 19} samples. The natural resonance was not happened due to the hard magnetic properties of these nano structure particles. - Highlights: • SrFe{sub 12}O{sub 19} and NiFe{sub 2}O{sub 4} nanostructure ferrite particles were synthesized via the co-precipitation of chloride salts. • Two kinds of peaks were seen for NiFe{sub 2}O{sub 4} at X-band (8–12 GHz); these phenomena were also happened for SrFe{sub 12}O{sub 19} samples. • The narrow peaks were remained unchanged and consistent while the wide ones were shifted by decreasing the thickness of the samples. • Characterization procedure was conducted utilizing the ferromagnetic resonance/transmit-line theories and Reflection Loss (RL) plots. • It was concluded that the natural ferromagnetic resonance can be lead to the narrow peaks while the wide ones can be related to the periodic effects.

  15. Poly(4-vinylphenol gate insulator with cross-linking using a rapid low-power microwave induction heating scheme for organic thin-film-transistors

    Directory of Open Access Journals (Sweden)

    Ching-Lin Fan

    2016-03-01

    Full Text Available A Microwave-Induction Heating (MIH scheme is proposed for the poly(4-vinylphenol (PVP gate insulator cross-linking process to replace the traditional oven heating cross-linking process. The cross-linking time is significantly decreased from 1 h to 5 min by heating the metal below the PVP layer using microwave irradiation. The necessary microwave power was substantially reduced to about 50 W by decreasing the chamber pressure. The MIH scheme is a good candidate to replace traditional thermal heating for cross-linking of PVP as the gate insulator for organic thin-film-transistors.

  16. Poly(4-vinylphenol) gate insulator with cross-linking using a rapid low-power microwave induction heating scheme for organic thin-film-transistors

    Science.gov (United States)

    Fan, Ching-Lin; Shang, Ming-Chi; Hsia, Mao-Yuan; Wang, Shea-Jue; Huang, Bohr-Ran; Lee, Win-Der

    2016-03-01

    A Microwave-Induction Heating (MIH) scheme is proposed for the poly(4-vinylphenol) (PVP) gate insulator cross-linking process to replace the traditional oven heating cross-linking process. The cross-linking time is significantly decreased from 1 h to 5 min by heating the metal below the PVP layer using microwave irradiation. The necessary microwave power was substantially reduced to about 50 W by decreasing the chamber pressure. The MIH scheme is a good candidate to replace traditional thermal heating for cross-linking of PVP as the gate insulator for organic thin-film-transistors.

  17. 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...

  18. Effective conversion of biomass tar into fuel gases in a microwave reactor

    Energy Technology Data Exchange (ETDEWEB)

    Anis, Samsudin, E-mail: samsudin-anis@yahoo.com [Department of Mechanical Engineering, Universitas Negeri Semarang, Kampus Sekaran, Gunungpati, 50229 Semarang, 8508101 (Indonesia); Zainal, Z. A., E-mail: mezainal@usm.my [School of Mechanical Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Penang (Malaysia)

    2016-06-03

    This work deals with conversion of naphthalene (C{sub 10}H{sub 8}) as a biomass tar model compound by means of thermal and catalytic treatments. A modified microwave oven with a maximum output power of 700 W was used as the experimental reactor. Experiments were performed in a wide temperature range of 450-1200°C at a predetermined residence time of 0.24-0.5 s. Dolomite and Y-zeolite were applied to convert naphthalene catalytically into useful gases. Experimental results on naphthalene conversion showed that conversion efficiency and yield of gases increased significantly with the increase of temperature. More than 90% naphthalene conversion efficiency was achieved by thermal treatment at 1200°C and 0.5 s. Nevertheless, this treatment was unfavorable for fuel gases production. The main product of this treatment was soot. Catalytic treatment provided different results with that of thermal treatment in which fuel gases formation was found to be the important product of naphthalene conversion. At a high temperature of 900°C, dolomite had better conversion activity where almost 40 wt.% of naphthalene could be converted into hydrogen, methane and other hydrocarbon gases.

  19. Analysis of Phthalate Migration to Food Simulants in Plastic Containers during Microwave Operations

    Science.gov (United States)

    Moreira, Miriany A.; André, Leiliane C.; Cardeal, Zenilda L.

    2013-01-01

    Phthalates used as plasticizers in the manufacture of household containers can potentially be transferred to foods that are stored or heated in these plastic containers. Phthalates are endocrine disruptor compounds (EDC) and are found in very low concentrations in foods, thus, highly sensitive analytical techniques are required for their quantification. This study describes the application of a new method developed for analyzing the migration of dibutylphthalate (DBP) and benzylbutylphthalate (BBP) from plastic food containers into liquid food simulants. This new method employs the technique of solid phase microextraction cooled with liquid nitrogen. The analysis was conducted by gas chromatography/mass spectrometry (GC/MS) using a polyacrylate fiber. Ultrapure water was used as a simulant for liquids foods, and both new and used plastic containers were placed in a domestic microwave oven for different periods of time at different power levels. The limits of detection for DBP and BBP were 0.08 µg/L and 0.31 µg/L, respectively. BBP was not found in the samples that were analyzed. DBP was found in concentrations ranging from containers that were used for a prolonged time, which correlated with increasing heating time. PMID:24380980

  20. Analysis of phthalate migration to food simulants in plastic containers during microwave operations.

    Science.gov (United States)

    Moreira, Miriany A; André, Leiliane C; Cardeal, Zenilda L

    2013-12-30

    Phthalates used as plasticizers in the manufacture of household containers can potentially be transferred to foods that are stored or heated in these plastic containers. Phthalates are endocrine disruptor compounds (EDC) and are found in very low concentrations in foods, thus, highly sensitive analytical techniques are required for their quantification. This study describes the application of a new method developed for analyzing the migration of dibutylphthalate (DBP) and benzylbutylphthalate (BBP) from plastic food containers into liquid food simulants. This new method employs the technique of solid phase microextraction cooled with liquid nitrogen. The analysis was conducted by gas chromatography/mass spectrometry (GC/MS) using a polyacrylate fiber. Ultrapure water was used as a simulant for liquids foods, and both new and used plastic containers were placed in a domestic microwave oven for different periods of time at different power levels. The limits of detection for DBP and BBP were 0.08 µg/L and 0.31 µg/L, respectively. BBP was not found in the samples that were analyzed. DBP was found in concentrations ranging from containers that were used for a prolonged time, which correlated with increasing heating time.

  1. Analysis of Phthalate Migration to Food Simulants in Plastic Containers during Microwave Operations

    Directory of Open Access Journals (Sweden)

    Miriany A. Moreira

    2013-12-01

    Full Text Available Phthalates used as plasticizers in the manufacture of household containers can potentially be transferred to foods that are stored or heated in these plastic containers. Phthalates are endocrine disruptor compounds (EDC and are found in very low concentrations in foods, thus, highly sensitive analytical techniques are required for their quantification. This study describes the application of a new method developed for analyzing the migration of dibutylphthalate (DBP and benzylbutylphthalate (BBP from plastic food containers into liquid food simulants. This new method employs the technique of solid phase microextraction cooled with liquid nitrogen. The analysis was conducted by gas chromatography/mass spectrometry (GC/MS using a polyacrylate fiber. Ultrapure water was used as a simulant for liquids foods, and both new and used plastic containers were placed in a domestic microwave oven for different periods of time at different power levels. The limits of detection for DBP and BBP were 0.08 µg/L and 0.31 µg/L, respectively. BBP was not found in the samples that were analyzed. DBP was found in concentrations ranging from

  2. Effective conversion of biomass tar into fuel gases in a microwave reactor

    Science.gov (United States)

    Anis, Samsudin; Zainal, Z. A.

    2016-06-01

    This work deals with conversion of naphthalene (C10H8) as a biomass tar model compound by means of thermal and catalytic treatments. A modified microwave oven with a maximum output power of 700 W was used as the experimental reactor. Experiments were performed in a wide temperature range of 450-1200°C at a predetermined residence time of 0.24-0.5 s. Dolomite and Y-zeolite were applied to convert naphthalene catalytically into useful gases. Experimental results on naphthalene conversion showed that conversion efficiency and yield of gases increased significantly with the increase of temperature. More than 90% naphthalene conversion efficiency was achieved by thermal treatment at 1200°C and 0.5 s. Nevertheless, this treatment was unfavorable for fuel gases production. The main product of this treatment was soot. Catalytic treatment provided different results with that of thermal treatment in which fuel gases formation was found to be the important product of naphthalene conversion. At a high temperature of 900°C, dolomite had better conversion activity where almost 40 wt.% of naphthalene could be converted into hydrogen, methane and other hydrocarbon gases.

  3. 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.

  4. 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.

  5. Microwave processing heats up

    Science.gov (United States)

    Microwaves are a common appliance in many households. In the United States microwave heating is the third most popular domestic heating method food foods. Microwave heating is also a commercial food processing technology that has been applied for cooking, drying, and tempering foods. It's use in ...

  6. Evaluation of microscopic structure of Justicia wynaadensis and the stability of its color extracted by using conventional and microwave extraction method.

    Science.gov (United States)

    Patil, Nital; Nigudkar, Manjusha; Sane, Ramesh; Ajitkumar, B S; Datar, Ajit

    2015-10-01

    Justicia wynaadensis locally known as Moddu Soppu belongs to the family Acanthaceae. The aqueous bluish purple color extracted from the leaves and stems of Justicia is used in the preparation of a sweet dish by the natives of Kodagu district, Karanataka, India, exclusively during the monsoons. This traditional practice is believed to keep the people healthy throughout the year. Owing to its potential to be used as a natural colorant there is a strong need to develop efficient extraction method for maximum yield of colorant and preliminary scientific study of stability. Microscopy was carried out to find out the location of purple color in both leaves and stem and to study the anatomical details. An optimized microwave extraction method for extraction of colorant from Justicia has been developed. The microwave oven extraction yield of colorant is 9.41 % (±0.8598) under the optimized conditions of extraction time 30 min., extraction temperature 150 °C and ratio of liquid to solid 30 ml/g. The study demonstrated that the purple extract of the plant was stable against pH range 6.0-8.0, low temperature (4 °C), high temperature (≥50 °C) and sensitive to light. Thus these observations recommend the use of J. wynaadensis extract as a food colorant in neutral or slightly alkaline products (bakery, milk, egg etc.) and could be the potential source for the food colorant market.

  7. Microwave thawing and green tea extract efficiency for the formation of acrylamide throughout the production process of chicken burgers and chicken nuggets.

    Science.gov (United States)

    Soncu, Eda Demirok; Kolsarici, Nuray

    2017-04-01

    Initially, we measured the acrylamide (AA) levels of chicken burgers (CBs) and chicken nuggets (CNs) purchased from fast food restaurants. After the determination of AA in these products, we aimed to investigate whether the use of green tea extract in the covering material, and microwave thawing before frying, mitigated the formation of AA in CBs and CNs during the production process. According to our study, AA concentrations of CBs and CNs purchased from fast food restaurants were in the range of 13.43-118.97 and 32.92-134.90 ng g-1 coating, respectively. In our experiment, AA levels varied between 19.61 and 40.08 ng g-1 coating for CBs and 7.92-49.60 ng g-1 coating for CNs. Green tea extract reduced the AA formation in CBs and CNs at the pan frying and steam oven cooking heat treatment steps (P microwave thawing did not affect AA level of CBs and CNs. When the AA levels of commercial CBs and CNs are compared with those produced in our experiment, the use of green tea extract could be a novel, easy and practical application for fast food producers to minimise AA levels in the first two steps of the production without changes to the sensory properties of the final products. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  8. The effect of short-time microwave exposures on Escherichia coli O157:H7 inoculated onto chicken meat portions and whole chickens.

    Science.gov (United States)

    Apostolou, I; Papadopoulou, C; Levidiotou, S; Ioannides, K

    2005-05-01

    Small portions of fresh chicken breasts weighting 20 g each and fresh whole chickens, weighting on average 1310 g each, were inoculated with Escherichia coli O157:H7 (10(5)-10(6) cfu/g) and cooked, using two different domestic microwave ovens at full power. The chicken portions were heated for 5, 10, 15, 20, 25, 30, and 35 s and the whole chickens for 22 min. Following exposures, viable counts and temperature measurements were performed. Although the chicken breast portions looked well-cooked after 30 s of MW heating at a mean end-point surface temperature of 69.8 degrees C, a mean concentration of 83 cfu/g E. coli O157:H7 cells was recovered. Elimination of E. coli O157:H7 cells occurred only after 35 s of MW exposure at 73.7 degrees C. When whole chickens were thoroughly cooked by MW heating, the final subsurface temperatures, measured in the thighs and wings, ranged from 60.2 degrees C to 92 degrees C and viable cells of E. coli O157:H7 were recovered from all samples of whole chicken. The results indicate that short time exposures of chicken portions to microwave heating do not eliminate E. coli O157:H7.

  9. 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

  10. Microwave RF antennas and circuits nonlinearity applications in engineering

    CERN Document Server

    Aluf, Ofer

    2017-01-01

    This book describes a new concept for analyzing RF/microwave circuits, which includes RF/microwave antennas. The book is unique in its emphasis on practical and innovative microwave RF engineering applications. The analysis is based on nonlinear dynamics and chaos models and shows comprehensive benefits and results. All conceptual RF microwave circuits and antennas are innovative and can be broadly implemented in engineering applications. Given the dynamics of RF microwave circuits and antennas, they are suitable for use in a broad range of applications. The book presents analytical methods for microwave RF antennas and circuit analysis, concrete examples, and geometric examples. The analysis is developed systematically, starting with basic differential equations and their bifurcations, and subsequently moving on to fixed point analysis, limit cycles and their bifurcations. Engineering applications include microwave RF circuits and antennas in a variety of topological structures, RFID ICs and antennas, micros...

  11. Remote measurement of microwave distribution based on optical detection

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Zhong; Ding, Wenzheng; Yang, Sihua; Chen, Qun, E-mail: redrocks-chenqun@hotmail.com, E-mail: xingda@scnu.edu.cn; Xing, Da, E-mail: redrocks-chenqun@hotmail.com, E-mail: xingda@scnu.edu.cn [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, South China Normal University, Guangzhou 510631 (China)

    2016-01-04

    In this letter, we present the development of a remote microwave measurement system. This method employs an arc discharge lamp that serves as an energy converter from microwave to visible light, which can propagate without transmission medium. Observed with a charge coupled device, quantitative microwave power distribution can be achieved when the operators and electronic instruments are in a distance from the high power region in order to reduce the potential risk. We perform the experiments using pulsed microwaves, and the results show that the system response is dependent on the microwave intensity over a certain range. Most importantly, the microwave distribution can be monitored in real time by optical observation of the response of a one-dimensional lamp array. The characteristics of low cost, a wide detection bandwidth, remote measurement, and room temperature operation make the system a preferred detector for microwave applications.

  12. Non-uniformity of surface temperatures after microwave heating of poultry meat.

    Science.gov (United States)

    Goksoy, E O; James, C; James, S J

    1999-01-01

    Microwave energy has the potential to raise the surface temperatures of meat rapidly for a short period of time sufficient to reduce bacterial numbers significantly without causing physical changes to the meat. Studies have investigated the ability of a standard domestic microwave oven (2450 MHz; IEC 1191 W), an experimental repeatable microwave cavity (2450 MHz; IEC 1139 W) and a number of shielding techniques to achieve uniform surface temperature distributions on pieces of poultry meat. In the domestic oven temperature differences of up to 60 and 80 degrees C were found between different points on the surface of the same sample after 30 s and 3 minutes of heating respectively. The use of a standard cavity and shielding resulted in a difference of less than 5 degrees C between the average surface temperature on the edge and middle of regular slabs of chicken after 30 s exposure. Results show that microwave heating, using 2450 MHz, is unlikely to produce consistently uniform enough surface temperatures on meat to reduce bacterial numbers without surface damage.

  13. Effects of susceptor, coating and conventional browning applications on color and crust formation during microwave baking.

    Science.gov (United States)

    Sahin, S; Sumnu, G; Zincirkiran, D

    2002-01-01

    The effects of different browning treatments on the crust color and crust hardness of microwave baked breads were investigated. Microwave oven was operated at 20%, 30% and 40% powers for 3.5-5.5 minutes. As a control, breads were baked in a conventional oven at 200 degrees C for 12 minutes. After microwave baking, breads were browned or conventional browning times increased, crust hardness and weight loss of breads increased. When susceptors were used, desired browning and hardness were obtained on the bottom surfaces of the breads. However, they did not affect top surface color significantly. The optimum microwave baking conditions for safety susceptor and standard susceptor were found as 5.0 minutes at 20% power and 4.5 minutes at 20% power, respectively. Breads coated with a solution composed of 10.5% sodium bicarbonate, 31.6% glucose, 5.3% glycine and 52.6% water (by weight) did not have the desired crust color and hardness. Conventional browning at 200 degrees C for 8 minutes was an alternative to achieve browning on top and bottom surfaces and crust formation on the bottom surface.

  14. Considering adaptation of electrical ovens with unit-type releasing to peculiarities of thermal energization of mineral raw materials

    Science.gov (United States)

    Zvezdin, A. V.; Bryanskikh, T. B.

    2017-01-01

    The paper gives a short overview of technologies of mineral raw material thermal treatment where application of electrical ovens with unit-type releasing is possible. Efficiency of such ovens for vermiculite concentrate and conglomerate roasting is proved by more than 13-years experience of their industrial operation. The paper furthermore considers alternative connections of energotechnological blocks of an oven in order to determine its efficient design for specific technology related to one or another mineral raw material.

  15. Feasibility study analysis for multi-function dual energy oven (case study: tapioca crackers small medium enterprise)

    Science.gov (United States)

    Soraya, N. W.; El Hadi, R. M.; Chumaidiyah, E.; Tripiawan, W.

    2017-12-01

    Conventional drying process is constrained by weather (cloudy / rainy), and requires wide drying area, and provides low-quality product. Multi-function dual energy oven is the appropriate technology to solve these problems. The oven uses solar thermal or gas heat for drying various type of products, including tapioca crackers. Investment analysis in technical, operational, and financial aspects show that the multi-function dual energy oven is feasible to be implemented for small medium enterprise (SME) processing tapioca crackers.

  16. Medical applications of microwaves

    Science.gov (United States)

    Vrba, Jan; Lapes, M.

    2004-04-01

    Medical applications of microwaves (i.e. a possibility to use microwave energy and/or microwave technique and technology for therapeutical purposes) are a quite new and a very rapidly developing field. Microwave thermotherapy is being used in medicine for the cancer treatment and treatment of some other diseases since early eighties. In this contribution we would like to offer general overview of present activities in the Czech Republic, i.e. clinical applications and results, technical aspects of thermo therapeutic equipment and last but not least, prospective diagnostics based on microwave principals ant technology and instrumentation.

  17. Control of microwave heating of peritoneal dialysis solutions.

    Science.gov (United States)

    Deutschendorf, A F; Wenk, R E; Lustgarten, J; Mason, P

    1994-01-01

    To determine if microwave heating of dialysis solutions to 37 degrees C produced focal overheating (hot spots) and caramelization of dextrose. In vitro determination of conditions for controlling time, temperature, and procedures. Bags had been stored at ambient room temperature. Solution and external bag surface temperature determinations. Dextrose degradation products determined spectrophotometrically. Microscopy for potential caramel precipitates. A microwave oven with no rotation tray produced uneven heating of bags of two commercially available concentrations of dialysis solutions. The greatest hot spots were evident in spike ports. External bag surface temperatures were within 0.20 degrees C of reservoir temperatures. Initial solution temperatures correlated with temperatures of the solutions after microwave heating (r = 0.895). No statistically significant differences were found between dextrose degradation product concentrations of unheated and heated solutions, including hot spots. No precipitates were observed microscopically. Despite the presence of solution hot spots in bag infusion ports, 37 degrees C temperatures were achievable in the bag reservoirs with no evidence of increased glucose degradation. This outcome is assured if the initial temperature and the microwave conditions (procedure, time, mixing of solution) are held constant, and the external bag temperatures are measured after heating.

  18. Microwave-assisted pyrolysis of microalgae for biofuel production.

    Science.gov (United States)

    Du, Zhenyi; Li, Yecong; Wang, Xiaoquan; Wan, Yiqin; Chen, Qin; Wang, Chenguang; Lin, Xiangyang; Liu, Yuhuan; Chen, Paul; Ruan, Roger

    2011-04-01

    The pyrolysis of Chlorella sp. was carried out in a microwave oven with char as microwave reception enhancer. The results indicated that the maximum bio-oil yield of 28.6% was achieved under the microwave power of 750 W. The bio-oil properties were characterized with elemental, GC-MS, GPC, FTIR, and thermogravimetric analysis. The algal bio-oil had a density of 0.98 kg/L, a viscosity of 61.2 cSt, and a higher heating value (HHV) of 30.7 MJ/kg. The GC-MS results showed that the bio-oils were mainly composed of aliphatic hydrocarbons, aromatic hydrocarbons, phenols, long chain fatty acids and nitrogenated compounds, among which aliphatic and aromatic hydrocarbons (account for 22.18% of the total GC-MS spectrum area) are highly desirable compounds as those in crude oil, gasoline and diesel. The results in this study indicate that fast growing algae are a promising source of feedstock for advanced renewable fuel production via microwave-assisted pyrolysis (MAP). Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Microwave-assisted solvent-free synthesis of 14-aryl/alkyl-14H-dibenzo[a,j]xanthenes and tetrahydrobenzo[a]xanthen-11-ones catalyzed by nano silica phosphoric acid

    Directory of Open Access Journals (Sweden)

    Abdolhamid Bamoniri

    2013-01-01

    Full Text Available Nano silica phosphoric acid (nano SPA was applied as a catalyst for synthesis of 14-aryl/alkyl-14H-dibenzo[a,j]xanthenes and tetrahydrobenzo[a]xanthen-11-ones in microwave oven under solvent free conditions. High efficiency, easy availability and reusability are some advantages of this catalyst.

  20. Sperm quality and DNA integrity of coke oven workers exposed to polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Jeng, Hueiwang Anna; Pan, Chih-Hong; Chao, Mu-Rong; Chiu, Chien-Chih; Zhou, Guodong; Chou, Chon-Kit; Lin, Wen-Yi

    2016-11-18

    The objective of this study was to assess sperm quality and deoxyribonucleic acid (DNA) integrity of coke oven workers exposed to polycyclic aromatic hydrocarbons (PAHs) as compared to control subjects. The coke oven workers (N = 52) and administrative staff (N = 35) of a steel plant served as the exposed and control groups, respectively. Exposure to PAHs was assessed by measuring 1-hydroxypyren. Analysis of sperm quality (concentration, motility, vitality, and morphology) was performed simultaneously with sperm DNA integrity analysis, including DNA fragmentation, denaturation, bulky DNA adducts, and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dGuo). A questionnaire was conducted to collect demographic and potential confounding data. The coke oven workers had lower percentages of sperm motility, vitality and normal morphology than the control group, but the difference was not significant. For DNA integrity, the coke oven workers had significantly higher concentrations of bulky DNA adducts and 8-oxo-dGuo than the control subjects (p = 0.009 and p = 0.048, respectively). However, DNA fragmentation percentages did not significantly increase as compared to those in the subjects from the control group (p = 0.232). There was no correlation between sperm quality parameters and DNA integrity indicators. Occupational exposure of the coke oven workers to PAHs was associated with decreased sperm DNA integrity. Int J Occup Med Environ Health 2016;29(6):915-926.

  1. Effect of repeated microwave disinfections on bonding of different commercial teeth to resin denture base.

    Science.gov (United States)

    Consani, Rafael L X; Soave, Tatiane; Mesquita, Marcelo F; Sinhoreti, Mario A C; Mendes, Wilson B; Guiraldo, Ricardo D

    2012-06-01

    To verify the influence of repeated microwave disinfections on the shear bond strength of two commercial types of teeth to acrylic resin, when the ridge lap surfaces were unmodified, bur abraded, bur grooved or etched by monomer. Eighty specimens (n = 10) were adhered to the tooth ridge lap surface, polymerised in a water bath at 74°C for 9 h. Microwaved specimens were individually immersed in 150 ml of water and submitted to five simulated disinfections in a microwave oven calibrated at 650 W for 3 min. Control specimens were not microwave treated. Shear bond strength tests were performed in an Instron machine with a cross-speed of 1 mm/min. The fracture load values were transformed into shear bond strength as a function of the bonding area (0.28 cm(2)). Data were submitted to ANOVA and Tukey's test (α = 0.05). Fractured areas were classified as adhesive, cohesive (resin or tooth) or mixed failures. Repeated microwave disinfections increased the shear strength of the tooth/resin bond. Mechanical retention in microwaved and non-microwaved procedures improved the shear bond strength. The different commercial types of teeth influenced shear bond strength values, with Biotone teeth showing the lower values. © 2011 The Gerodontology Society and John Wiley & Sons A/S.

  2. 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.

  3. Self-propagating high-temperature synthesis (SHS) and microwave-assisted combustion synthesis (MACS) of the thallium superconducting phases

    Science.gov (United States)

    Bayya, S. S.; Snyder, R. L.

    1994-05-01

    This paper explores the speed of reaction as a parameter to minimizing thallium loss. Self-propagating high-temperature synthesis (SHS) and microwave-assisted combustion synthesis (MACS) were developed for the synthesis of Tl-2212 and Tl-2223 superconductors using Cu metal powder as a fuel. A kitchen microwave oven was used to carry out MACS reactions. The samples were reacted for few seconds and led to the formation of the superconducting phases. Further explorations and modifications in the processing could lead to the formation of single phases by MACS.

  4. Assessment of genotoxic exposure in Swedish coke-oven work by different methods of biological monitoring.

    Science.gov (United States)

    Reuterwall, C; Aringer, L; Elinder, C G; Rannug, A; Levin, J O; Juringe, L; Onfelt, A

    1991-04-01

    This study evaluated the results of several biological methods used simultaneously to monitor coke-oven work. Blood samples from 44 male coke-oven workers and 48 male referents, matched for age and smoking/snuff consumption, were examined for cytogenetic damage in lymphocytes. Urinary thioether excretion was determined for 62, and urine mutagenicity for 31, of the subjects, who followed a standardized diet during the urine sampling. Exposure to polycyclic aromatic hydrocarbons varied with work task, the ambient air levels of benzo[a]pyrene sometimes exceeding 5 micrograms/m3. Cytogenetic damage, urine mutagenicity, and thioether excretion did not differ between the groups. The smokers, however, had significantly higher sister chromatid exchange frequencies, urine mutagenicity, and thioether excretion than the nonsmokers. The absence of biological indications of genotoxic exposure was unexpected and indicates that the studied methods are not adequate to assess the carcinogenic risks of Swedish coke-oven workers.

  5. Comparison study on biosynthesis of silver nanoparticles using fresh and hot air oven dried IMPERATA CYLINDRICA leaf

    Science.gov (United States)

    Najmi Bonnia, Noor; Fairuzi, Afiza Ahmad; Akhir, Rabiatuladawiyah Md.; Yahya, Sabrina M.; Rani, Mohd Azri Ab; Ratim, Suzana; Rahman, Norafifah A.; Akil, Hazizan Md

    2018-01-01

    The perennial rhizomatous grass; Imperata cylindrica (I. cylindrica) has been reported rich in various phytochemicals. In present study, silver nanoparticles were synthesized from aqueous leaf extract of I. cylindrica at two different leaf conditions; fresh leaves and hot-air oven dried leaves. Biosynthesized silver nanoparticles were characterized by UV-visible spectroscopy, field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FTIR). Maximum absorption was recorded between 400 nm to 500 nm. FESEM analysis revealed that the silver nanoparticles predominantly form spherical shapes. The particles sizes were ranging from 22-37 nm. The elemental composition of the synthesized silver nanoparticles was confirmed by using energy dispersive X-ray spectroscopy (EDX) analysis. Fourier transform infrared spectroscopy (FTIR) confirmed the reducing and stabilizing actions came from biomolecules associated with I. cylindrica leaf extract. Thus in this investigation, an environmentally safe method to synthesized silver nanoparticles using local plant extract was successfully established.

  6. Optimization of bioresource material from oil palm trunk core drying using microwave radiation; a response surface methodology application.

    Science.gov (United States)

    Amouzgar, Parisa; Khalil, H P S Abdul; Salamatinia, Babak; Abdullah, Ahmad Zuhairi; Issam, A M

    2010-11-01

    In this study optimization of drying oil palm trunk core lumber (OPTCL) biomass using microwave radiation was reported. Optimizing of the drying conditions using microwave, avoid burning, shrinkage and increasing the permeability of OPT was aimed to develop a new value added material. A set of experiments was designed by central composite design using response surface methodology (RSM) to statistically evaluate the findings. Three independent process variables including time (2-10 min), sample weight (300-1000 g) and input power (660-3300 W) were studied under the given conditions designed by Design Expert software. The results showed the effectiveness of microwave drying in reducing the time and better removal of moisture as compared to that of oven drying with no significant changes. Employing optimum conditions at 6.89 min of time with a microwave power set at 4 for a sample of 1000 g, predicting 14.62% of moisture content.

  7. Production of bio-fuels by high temperature pyrolysis of sewage sludge using conventional and microwave heating.

    Science.gov (United States)

    Domínguez, A; Menéndez, J A; Inguanzo, M; Pís, J J

    2006-07-01

    The pyrolysis of sewage sludge was investigated using microwave and electrical ovens as the sources of heat, and graphite and char as microwave absorbers. The main objective of this work was to maximize the gas yield and to assess its quality as a fuel and as a source of hydrogen or syngas (H2 + CO). Both gases were produced in a higher proportion by microwave pyrolysis than by conventional pyrolysis, with a maximum value of 38% for H2 and 66% for H2 + CO. The oils obtained were also characterized using FTIR and GC-MS. The use of conventional electrical heating in the pyrolysis of sewage sludge produced an oil that could have a significant environmental and toxicological impact. Conversely, microwave pyrolysis still preserved some of the functional groups of the initial sludge such as aliphatic and oxygenated compounds, whereas no heavy PACs were detected.

  8. Microwave plasma-enhanced chemical vapour deposition growth of carbon nanostructures

    Directory of Open Access Journals (Sweden)

    Shivan R. Singh

    2010-05-01

    Full Text Available The effect of various input parameters on the production of carbon nanostructures using a simple microwave plasma-enhanced chemical vapour deposition technique has been investigated. The technique utilises a conventional microwave oven as the microwave energy source. The developed apparatus is inexpensive and easy to install and is suitable for use as a carbon nanostructure source for potential laboratory-based research of the bulk properties of carbon nanostructures. A result of this investigation is the reproducibility of specific nanostructures with the variation of input parameters, such as carbon-containing precursor and support gas flow rate. It was shown that the yield and quality of the carbon products is directly controlled by input parameters. Transmission electron microscopy and scanning electron microscopy were used to analyse the carbon products; these were found to be amorphous, nanotubes and onion-like nanostructures.

  9. A Novel Method of Preparation of Inorganic Glasses by Microwave Irradiation

    Science.gov (United States)

    Vaidhyanathan, B.; Ganguli, Munia; Rao, K. J.

    1994-12-01

    Microwave heating is shown to provide an extremely facile and automatically temperature-controlled route to the synthesis of glasses. Glass-forming compositions of several traditional and novel glasses were melted in a kitchen microwave oven, typically within 5 min and quenched into glasses. This is only a fraction of the time required in normal glass preparation methods. The rapidity of melting minimizes undesirable features such as loss of components of the glass, variation of oxidation states of metal ions, and oxygen loss leading to reduced products in the glass such as metal particles. This novel procedure of preparation is applicable when at least one of the components of the glass-forming mixture absorbs microwaves.

  10. Construction of imaging system for wide-field-range ESR spectra using localized microwave field and its case study of crystal orientation in suspension of copper sulfate pentahydrate (CuSO4 . 5H2O).

    Science.gov (United States)

    Tani, Atsushi; Ueno, Takehiro; Yamanaka, Chihiro; Katsura, Makoto; Ikeya, Motoji

    2005-02-01

    A scanning electron spin resonance (ESR) microscope using a localized microwave field was redesigned to measure ESR spectra from 0 to 400 mT using electromagnets. Divalent copper ion (Cu2+) in copper sulfate pentahydrate (CuSO4 . 5H2O) was imaged, after the powdered samples were cemented in silicone rubber under a magnetic field. The ratio of the two signal intensities at g=2.27 and 2.08 clearly indicates the orientation of the particles. This method can be used for mapping the local magnetic field and its direction.

  11. Construction of imaging system for wide-field-range ESR spectra using localized microwave field and its case study of crystal orientation in suspension of copper sulfate pentahydrate (CuSO{sub 4}.5H{sub 2}O)

    Energy Technology Data Exchange (ETDEWEB)

    Tani, Atsushi [Department of Earth and Space Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama Toyonaka, Osaka 560-0043 (Japan)]. E-mail: atani@ess.sci.osaka-u.ac.jp; Ueno, Takehiro [Department of Earth and Space Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama Toyonaka, Osaka 560-0043 (Japan); Yamanaka, Chihiro [Department of Earth and Space Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama Toyonaka, Osaka 560-0043 (Japan); Katsura, Makoto [Department of Earth and Space Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama Toyonaka, Osaka 560-0043 (Japan); Ikeya, Motoji [Department of Earth and Space Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama Toyonaka, Osaka 560-0043 (Japan)

    2005-02-01

    A scanning electron spin resonance (ESR) microscope using a localized microwave field was redesigned to measure ESR spectra from 0 to 400mT using electromagnets. Divalent copper ion (Cu{sup 2+}) in copper sulfate pentahydrate (CuSO{sub 4}.5H{sub 2}O) was imaged, after the powdered samples were cemented in silicone rubber under a magnetic field. The ratio of the two signal intensities at g=2.27 and 2.08 clearly indicates the orientation of the particles. This method can be used for mapping the local magnetic field and its direction.

  12. Comparative evaluation of surface porosities in conventional heat polymerized acrylic resin cured by water bath and microwave energy with microwavable acrylic resin cured by microwave energy

    Directory of Open Access Journals (Sweden)

    Sunint Singh

    2013-01-01

    Full Text Available Background: Conventional heat cure poly methyl methacrylate (PMMA is the most commonly used denture base resin despite having some short comings. Lengthy polymerization time being one of them and in order to overcome this fact microwave curing method was recommended. Unavailability of specially designed microwavable acrylic resin made it unpopular. Therefore, in this study, conventional heat cure PMMA was polymerized by microwave energy. Aim and Objectives: This study was designed to evaluate the surface porosities in PMMA cured by conventional water bath and microwave energy and compare it with microwavable acrylic resin cured by microwave energy. Materials and Methods: Wax samples were obtained by pouring molten wax into a metal mold of 25 mm × 12 mm × 3 mm dimensions. These samples were divided into three groups namely C, CM, and M. Group C denotes conventional heat cure PMMA cured by water bath method, CM denotes conventional heat cure PMMA cured by microwave energy, M denotes specially designed microwavable acrylic denture base resin cured by microwave energy. After polymerization, each sample was scanned in three pre-marked areas for surface porosities using the optical microscope. As per the literature available, this instrument is being used for the first time to measure the porosity in acrylic resin. It is a reliable method of measuring area of surface pores. Portion of the sample being scanned is displayed on the computer and with the help of software area of each pore was measured and data were analyzed. Results: Conventional heat cure PMMA samples cured by microwave energy showed maximum porosities than the samples cured by conventional water bath method and microwavable acrylic resin cured by microwave energy. Higher percentage of porosities was statistically significant, but well within the range to be clinically acceptable. Conclusion: Within the limitations of this in-vitro study, conventional heat cure PMMA can be cured by

  13. A comparison of techniques for preparing fish fillet for ICP-AES multielemental analysis and the microwave digestion of whole fish.

    Science.gov (United States)

    Moeller, A; Ambrose, R F; Que Hee, S S

    2001-01-01

    Four catfish fillet homogenate treatments before multielemental metal analysis by simultaneous inductively coupled plasma/atomic emission spectroscopy were compared in triplicate. These treatments were: nitric acid wet-ashing by Parr bomb digestion; nitric acid wet-ashing by microwave digestion; tetramethylammonium hydroxide/nitric acid wet digestion; and dry-ashing. The tetramethylammonium hydroxide/nitric acid method was imprecise (coefficients of variation > 20%). The dry-ashing method was fast and sensitive but had low recoveries of 50% for spiked Pb and Al and was not as precise as the Parr bomb or microwave treatments. The Parr bomb method was the most precise method but was less sensitive than the microwave method which had nearly the same precision. The microwave method was then adapted to homogenates of small whole fish microwave oven system allowed precise results for fillet and whole fish homogenates.

  14. Simultaneous application of microwave energy and hot air to whole drying process of apple slices: drying kinetics, modeling, temperature profile and energy aspect

    Science.gov (United States)

    Horuz, Erhan; Bozkurt, Hüseyin; Karataş, Haluk; Maskan, Medeni

    2017-09-01

    Drying kinetics, modeling, temperature profile and energy indices were investigated in apple slices during drying by a specially designed microwave-hot air domestic hybrid oven at the following conditions: 120, 150 and 180 W microwave powers coupled with 50, 60 and 70 °C air temperatures. Both sources of energy were applied simultaneously during the whole drying processes. The drying process continued until the moisture content of apple slices reached to 20% from 86.3% (wet basis, w.b). Drying times ranged from 330 to 800 min and decreased with increasing microwave power and air temperatures. The constant rate period was only observed at low microwave powers and air temperatures. Two falling rate periods were observed. Temperature of apple slices sharply increased within the first 60 min, then reached equilibrium with drying medium and finally increased at the end of the drying process. In order to describe drying behavior of apple slices nine empirical models were applied. The Modified Logistic Model fitted the best our experimental data (R 2 = 0.9955-0.9998; χ 2 = 3.46 × 10-5-7.85 × 10-4 and RMSE = 0.0052-0.0221). The effective moisture and thermal diffusivities were calculated by Fick's second law and ranged from 1.42 × 10-9 to 3.31 × 10-9 m2/s and 7.70 × 10-9 to 12.54 × 10-9 m2/s, respectively. The activation energy (Ea) values were calculated from effective moisture diffusivity (Deff), thermal diffusivity (α) and the rate constant of the best model (k). The Ea values found from these three terms were similar and varied from 13.04 to 33.52 kJ/mol. Energy consumption and specific energy requirement of the hybrid drying of apple slices decreased and energy efficiency of the drying system increased with increasing microwave power and air temperature. Apples can be dried rapidly and effectively by use of the hybrid technique.

  15. Microwave radiation (2.45 GHz)-induced oxidative stress: Whole-body exposure effect on histopathology of Wistar rats.

    Science.gov (United States)

    Chauhan, Parul; Verma, H N; Sisodia, Rashmi; Kesari, Kavindra Kumar

    2017-01-01

    Man-made microwave and radiofrequency (RF) radiation technologies have been steadily increasing with the growing demand of electronic appliances such as microwave oven and cell phones. These appliances affect biological systems by increasing free radicals, thus leading to oxidative damage. The aim of this study was to explore the effect of 2.45 GHz microwave radiation on histology and the level of lipid peroxide (LPO) in Wistar rats. Sixty-day-old male Wistar rats with 180 ± 10 g body weight were used for this study. Animals were divided into two groups: sham exposed (control) and microwave exposed. These animals were exposed for 2 h a day for 35 d to 2.45 GHz microwave radiation (power density, 0.2 mW/cm(2)). The whole-body specific absorption rate (SAR) was estimated to be 0.14 W/kg. After completion of the exposure period, rats were sacrificed, and brain, liver, kidney, testis and spleen were stored/preserved for determination of LPO and histological parameters. Significantly high level of LPO was observed in the liver (p microwave radiation. Also histological changes were observed in the brain, liver, testis, kidney and spleen after whole-body microwave exposure, compared to the control group. Based on the results obtained in this study, we conclude that exposure to microwave radiation 2 h a day for 35 d can potentially cause histopathology and oxidative changes in Wistar rats. These results indicate possible implications of such exposure on human health.

  16. Performance and microbial community analysis of the anaerobic reactor with coke oven gas biomethanation and in situ biogas upgrading

    DEFF Research Database (Denmark)

    Wang, Wen; Xie, Li; Luo, Gang

    2013-01-01

    A new method for simultaneous coke oven gas (COG) biomethanation and in situ biogas upgrading in anaerobic reactor was developed in this study. The simulated coke oven gas (SCOG) (92% H2 and 8% CO) was injected directly into the anaerobic reactor treating sewage sludge through hollow fiber membra...

  17. Reference method for total water in lint cotton by automated oven drying combined with volumetric Karl Fischer titration

    Science.gov (United States)

    In a preliminary study to measure total water in lint cotton we demonstrated that volumetric Karl Fischer Titration of moisture transported by a carrier gas from an attached small oven is more accurate than standard oven drying in air. The objective of the present study was to assess the measuremen...

  18. Understanding the bias between moisture content by oven drying and water content by Karl Fischer titration at moisture equilibrium

    Science.gov (United States)

    Multiple causes of the difference between equilibrium moisture and water content have been found. The errors or biases were traced to the oven drying procedure to determine moisture content. The present paper explains the nature of the biases in oven drying and how it is possible to suppress one ...

  19. 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

  20. 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

  1. [Relationship between CYP1A1 gene polymorphisms and urinary 1-hydroxypyrene levels in coke oven workers].

    Science.gov (United States)

    Nie, Ji-sheng; Zhang, Hong-mei; Sun, Jian-ya; Zeng, Ping; Zhang, Ling; Niu, Qiao

    2009-05-01

    To study the associations of CYP1A1 gene polymorphisms with levels of urinary 1-hydroxypyrene among coke oven workers. 223 male workers from a coke plant (76, 82 and 65 workers in oven top group, oven-side group and oven-bottom group respectively) and 119 controls without occupational polycyclic aromatic hydrocarbons exposure were selected. The MspI gene polymorphism in CYP1A1 3' flanking region and the genotypes at I462V site in exon 7 of CYP1A1 were detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and allele specific amplification (ASA). The urinary 1-hydroxypyrene of coke oven workers in oven-top, oven-side and oven-bottom (3.77+/-0.64, 3.57+/-0.49, 3.26+/-0.80 micromol/mol Cr) were significantly higher than controls (2.80+/-1.02 micromol/mol Cr) (P0.05). In oven-top group and oven-side group, the subjects with Val/Val genotype in exon 7 of CYP1A1 had significantly higher urinary 1-hydroxypyrene levels than those with Ile/Val or Ile/Ile genotype, and urinary 1-hydroxypyrene of Ile-Val genotype were also significantly higher than Ile/Ile genotype (Poven workers (OR in oven top group, oven-side group and oven-bottom group was 24.926, 4.226 and 6.729 respectively) and subjects with m2/m2 genotype in CYP1A1 3' flanking region (OR=4.031) or with Val/Val or Ile/Val genotype in exon 7 of CYP1A1 (OR were 5.524 and 3.811) had elevated urinary 1-hydroxypyrene (greater than 95 percentile of control group, 3.876 micromol/mol Cr). BAP concentration of work environment contributes to the elevated urinary 1-hydroxypyrene levels, and the exposed BAP levels were regulated by the CYP1A1 MspI and I462V genotypes. Genetic polymorphism of CYP1A1 gene could be a susceptible biomarker in coke oven workers which was involved in the individual susceptibility on metabolism of PAHs.

  2. Not child's play: National estimates of microwave-related burn injuries among young children.

    Science.gov (United States)

    Lowell, Gina; Quinlan, Kyran

    2016-10-01

    Previous studies have shown that children as young as 18 months can open a microwave and remove its contents causing sometimes severe scalds. Although this mechanism may be uniquely preventable by an engineering fix, no national estimate of this type of child burn injury has been reported. We analyzed the Consumer Product Safety Commission's National Electronic Injury Surveillance System data on emergency department-treated microwave-related burn injuries from January 2002 through December 2012 in children aged 12 months to 4 years. Based on the narrative description of how the injury occurred, we defined a case as a burn with a mechanism of either definitely or probably involving a child himself or herself opening a microwave oven and accessing the heated contents. National estimates of cases and their characteristics were calculated. During the 11 years studied, an estimated 10,902 (95% confidence interval, 8,231-13,573) microwave-related burns occurred in children aged 12 months to 4 years. Of these, 7,274 (66.7%) (95% confidence interval, 5,135-9,413) were cases of children burned after accessing the contents of the microwave themselves. A total of 1,124 (15.5%) cases required hospitalization or transfer from the treating emergency department. Narratives for children as young as 12 months described the child himself or herself being able to access microwave contents. The most commonly burned body parts were the upper trunk (3,056 cases) and the face (1,039 cases). The most common scalding substances were water (2,863 cases), noodles (1,011 cases), and soup (931 cases). The majority of microwave-related burns in young children occur as a result of the child himself or herself accessing the microwave and removing the contents. More than 600 young children are treated in US emergency departments annually for such burns. Children as young as 12 months sustained burns caused by this mechanism of injury. These burns could be prevented with a redesign of microwaves to

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

    Science.gov (United States)

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

    2008-06-01

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

  4. A solar oven in the aim of reducing wood consumption in the Sahel

    Energy Technology Data Exchange (ETDEWEB)

    Ba, A.; Hamadou, A. [Centre National d' Energie Solaire, Niamey (Nigeria); Saley, H.A. [UDUS, Sokoto (Niger)

    2004-07-01

    01 Traditional ovens working with large amount of wood are used by butchers to roast mutton in Niger. As we know, this country is mostly occupied by Sahara desert. It is quite important to preserve its forest and all initiative to reduce wood consumption is welcome. That is one of the reasons that a solar oven is conceived. It is a hot box type solar cooker that has parallelepiped form with 1200 mm length, 975 mm width, and 755 mm height, the all with four rollers feet. The absorber is half cylinder, constituted with a black-painted sheet and with 1100 mm length and 965 mm diameter. The oven has a double glass cover and two reflectors permitting the increase of solar radiation in the box. The external wall is constituted of wood board on which a layer of varnish has been putted. Between the board and the absorber there is a glass wool insulation of 25 mm thickness. Tests have been run to characterise the oven: -temperature profile in the box (from the bottom to the glass cover) -efficiency of the cooker calculated - economic aspects examined. (orig.)

  5. Mathematical modeling for temperature and concentration study inside a thermal drying oven

    Science.gov (United States)

    Tanthadiloke, Surasit; Kittisupakorn, Paisan

    2017-08-01

    In order to investigate the dynamic behavior for further performance improvements of a thermal drying oven in a can production plant, mathematical models based on continuity equations are developed and validated with COMSOL simulation result. Profiles of temperature and the concentration of evaporated solvent (Ethylene glycol monobutyl ether; C6H14O2) in three different volumetric air flow rates such as 1.67, 1.00 and 0.33 m3/s are investigated and compared with the simulation results. The results demonstrated that the developed models for the thermal drying oven provide good prediction with a very small error from the validating data and the coefficient of determination (R2) of these models is 0.9926. Furthermore, these models can keep a good evaluation of both temperature and the concentration of evaporated solvent when changing the volumetric air flow rates. The simulation results from the developed models in all cases have the similar trends when compared with the COMSOL results. In addition, the results in this work guarantee that the developed models can provide the dynamic behavior inside the thermal drying oven and are applicable for the future improvements of the thermal drying oven performance.

  6. Heat transfer and heating rate of food stuffs in commercial shop ovens

    Indian Academy of Sciences (India)

    Heat transfer and heating rate of food stuffs in commercial shop ovens. P NAVANEETHAKRISHNAN. ∗. , P S S SRINIVASAN and. S DHANDAPANI. Department of Mechanical Engineering, Kongu Engineering College,. Perundurai 638 052 e-mail: pnkmech@gmail.com, pnkmech@yahoo.co.in. MS received 24 May 2006; ...

  7. Studies on Some Major and Trace Metals in Smoked and Oven ...

    African Journals Online (AJOL)

    The mineral (Li, Na, K, Ca, Mg, Fe, Cu, Mn, Zn and Pb) composition of each of five species of fish, including Sarotherodon galilaues, Cyprinus carpio, Clarias gariepinus, Sardinella spp. and Labeo spp. Was determined in samples previously dried, either by traditional smoking method, or in laboratory oven, to gain ...

  8. Innovative coke oven gas cleaning system for retrofit applications. Volume 1, Public design report

    Energy Technology Data Exchange (ETDEWEB)

    1994-05-24

    This Public Design Report provides, in a single document, available nonproprietary design -information for the ``Innovative Coke Oven Gas Cleaning System for Retrofit Applications`` Demonstration Project at Bethlehem Steel Corporation`s Sparrows Point, Maryland coke oven by-product facilities. This project demonstrates, for the first time in the United States, the feasibility of integrating four commercially available technologies (processes) for cleaning coke oven gas. The four technologies are: Secondary Gas Cooling, Hydrogen Sulfide and Ammonia Removal, Hydrogen Sulfide and Ammonia Recovery, and Ammonia Destruction and Sulfur Recovery. In addition to the design aspects, the history of the project and the role of the US Department of,Energy are briefly discussed. Actual plant capital and projected operating costs are also presented. An overview of the integration (retrofit) of the processes into the existing plant is presented and is followed by detailed non-proprietary descriptions of the four technologies and their overall effect on reducing the emissions of ammonia, sulfur, and other pollutants from coke oven gas. Narrative process descriptions, simplified process flow diagrams, input/output stream data, operating conditions, catalyst and chemical requirements, and utility requirements are given for each unit. Plant startup provisions, environmental considerations and control monitoring, and safety considerations are also addressed for each process.

  9. Effect of microwave blanching on the quality of frozen Agaricus bisporus.

    Science.gov (United States)

    Bernaś, Emilia; Jaworska, Grażyna

    2015-06-01

    The aim of this work was to determine the effect of microwave blanching on the levels of selected quality parameters in frozen Agaricus bisporus. Before freezing, mushrooms underwent one of the following treatments: blanching in water; blanching in a solution of sodium metabisulphite and citric acid; microwaving for 5 min; and combined blanching (first in water, then in a microwave oven). Products were freeze stored for 8 months at -25 ℃. Frozen storage resulted in decreased levels of vitamin B1, total polyphenols and antioxidant activity of 10-49%, as well as an increase in polyphenol oxidase activity compared with products immediately after freezing. The values for most colour parameters and whiteness intensity decreased, while cream, yellow, brown and grey saturation increased. There was a considerable deterioration in sensory quality, particularly colour. Microwave-blanched products had significantly higher dry matter, ash, vitamin B1 and B2 content than the remaining products as well as half the polyphenol oxidase activity. Total polyphenols and antioxidant activity were highest in the product blanched in the sodium metabisulphite solution, followed by the microwave-blanched product. Compared with the product blanched using sodium metabisulphite, microwave-blanched mushrooms showed slightly greater darkening but were superior in flavour and aroma. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  10. A cryogenic measurement setup for characterization microwave devices

    DEFF Research Database (Denmark)

    Rybalko, Oleksandr

    2017-01-01

    A cryogenic measurement setup for characterization microwave devices from room to cryogenic temperatures is presented. The setup allows testing microwave devices at variable temperatures ranging from 300 to 77 K. Frequency doubler (94/188 GHz) has been cooled to 77 K and peak efficiency of 32...

  11. The study of thermal interaction and microstructure of sodium silicate/bentonite composite under microwave radiation

    Energy Technology Data Exchange (ETDEWEB)

    Subannajui, Kittitat, E-mail: kittitat.sub@mahidol.ac.th [Faculty of Science, Mahidol University, 272 Rama VI Road, Ratchathewi District, Bangkok 10400 (Thailand); Center of Nanoscience and Nanotechnology Research Unit, Mahidol University, 272 Rama VI Road, Ratchathewi District, Bangkok 10400 (Thailand)

    2016-12-01

    The commercial heating oven usually consumes the power around 2500–3000 Watt and the temperature inside the oven is still below 350 °C. If we need to increase a temperature above 500 °C, a special heating setup with a higher power furnace is required. However, in this work, we propose a composite material that interacts with 2.45 GHz 500 Watt microwave and rapidly redeems the thermal energy with the temperature around 600–900 °C. The composite amorphous material easily forms liquid ceramics phase with a high temperature output and responds to the microwave radiation better than that of the solid phase. During the heating process, phase transformation occurs. This method is very effective and can be used to drastically reduce the power consumption of any heating process. - Highlights: • Amorphous phase transforms to liquid phase by microwave radiation. • Pure sodium silicate and pure bentonite cannot show temperature overshoot. • Silicate-bentonite composite shows a high temperature overshoot above 700 °C. • A rapid heating crucible for the annealing application is fabricated.

  12. Dual modification of taro starch by microwave and other heat moisture treatments.

    Science.gov (United States)

    Deka, Dhritiman; Sit, Nandan

    2016-11-01

    Effect of heat moisture treatment on the physicochemical properties of taro starch with 25% moisture (w/w) modified by single treatments of microwave (HMT1), autoclave (HMT2) and hot air oven (HMT3), and dual treatments of microwave followed by autoclave (HMT4) and microwave followed by hot air oven (HMT5) were investigated. Amylose contents of the modified starches increased except for HMT3. A loss of physical integrity of the starch granules were observed for dual modified starches. The swelling and solubility of all the modified starches increased. The peak viscosities of starches modified by HMT1 and HMT5 were found to be higher whereas for other modified starches it was lower than that of native starch. The holding and final viscosities of all the modified starches except HMT4 were higher than native starch. The freeze-thaw stabilities of the modified starches were also found to be better than that of native starch. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Microwave calorimetry using X-rays

    Energy Technology Data Exchange (ETDEWEB)

    Nicula, R., E-mail: radu.nicula@empa.ch [Empa, Swiss Federal Laboratories for Materials Science and Technology, Advanced Materials Processing, Feuerwerkerstr. 39, CH-3602 Thun (Switzerland); Stir, M. [Empa, Swiss Federal Laboratories for Materials Science and Technology, Advanced Materials Processing, Feuerwerkerstr. 39, CH-3602 Thun (Switzerland); Wurm, A. [University of Rostock, Institute of Physics, Wismarsche Str. 43-45, 18051 Rostock (Germany); Catala-Civera, J.M. [Universidad Politecnica de Valencia, Camino Vera s/n, E-46022 Valencia (Spain); Ishizaki, K.; Vaucher, S. [Empa, Swiss Federal Laboratories for Materials Science and Technology, Advanced Materials Processing, Feuerwerkerstr. 39, CH-3602 Thun (Switzerland); Zhuravlev, E.; Schick, C. [University of Rostock, Institute of Physics, Wismarsche Str. 43-45, 18051 Rostock (Germany)

    2011-11-10

    Highlights: Black-Right-Pointing-Pointer New approach for microwave calorimetry using synchrotron radiation powder diffraction. Black-Right-Pointing-Pointer In situ monitoring of the magnetostructural transformation of Co under magnetic microwave heating at 2.45 GHz. Black-Right-Pointing-Pointer Magnetic heat capacity of Co due to the spin-reorientation transition at microwave frequencies. - Abstract: An alternative approach for microwave calorimetry is proposed which relies on the synchrotron radiation powder diffraction technique as well as on the Grueneisen formalism for the analysis of thermal expansion. Cobalt was selected as suitable magnetic material for the present evaluation of the method. First results are reported concerning the calorimetric assessment of the HCP (hexagonal close-packed) to FCC (face centered cubic) transition of cobalt from in situ time-resolved X-ray diffraction experiments performed during magnetic (H-field) microwave heating. The X-ray calorimetry method yields specific heat capacity estimations that compare well with results from conventional differential scanning calorimetry measurements. In the presence of the 2.45 GHz microwave H-field, an 'anomalous' behaviour of the heat capacity across the structural phase transition is detected, which can be correlated with the magnetic spin reorientation transition of cobalt in the same temperature range.

  14. Microbial inactivation by microwave radiation in the home environment.

    Science.gov (United States)

    Park, Dong-Kyoo; Bitton, Gabriel; Melker, Richard

    2006-12-01

    The study reported here looked at the survival of microorganisms (heterotrophic plate counts, total coliforms, E. coli, and bacterial spores) in a consumer-type microwave oven. Kitchen sponges, scrubbing pads, and syringes were experimentally contaminated with wastewater and subsequently exposed to microwave radiation. At 100 percent power level, it was found that the heterotrophic plate count (i.e., total bacterial count) of the wastewater was reduced by more that 99 percent within 1 to 2 minutes, and the total coliform and E. coli were totally inactivated after 30 seconds of microwave radiation. Bacterial phage MS2 was totally inactivated within 1 to 2 minutes. Spores of Bacillus cereus were more resistant than the other microorganisms tested, and were completely eradicated only after 4-minute irradiation. Similar inactivation rates were obtained in wastewater-contaminated scrubbing pads. Microorganisms attached to plastic syringes were more resistant to microwave irradiation than those associated with kitchen sponges or scrubbing pads. It took 10 minutes for total inactivation of the heterotrophic plate count and 4 minutes for total inactivation of total coliform and E. coli. A 4-log reduction of phage MS2 was obtained after 2 minutes; 97.4 percent reduction was observed after 12 minutes. The authors also observed a higher inactivation of B. cereus spores in syringes placed in a ceramic container than of spores in syringes placed in a glass container. This finding could have some implications for the design of containers to be used in exposure of medical devices to microwave radiation. The article discusses the implications of these findings for consumer safety in the home environment.

  15. Integrated microwave photonics

    NARCIS (Netherlands)

    Marpaung, D.A.I.; Roeloffzen, C.G.H.; Heideman, Rene; Leinse, Arne; Sales, S.; Capmany, J.

    2013-01-01

    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

  16. Microwave SQUID multiplexer demonstration for cosmic microwave background imagers

    Science.gov (United States)

    Dober, B.; Becker, D. T.; Bennett, D. A.; Bryan, S. A.; Duff, S. M.; Gard, J. D.; Hays-Wehle, J. P.; Hilton, G. C.; Hubmayr, J.; Mates, J. A. B.; Reintsema, C. D.; Vale, L. R.; Ullom, J. N.

    2017-12-01

    Key performance characteristics are demonstrated for the microwave superconducting quantum interference device (SQUID) multiplexer (μmux) coupled to transition edge sensor (TES) bolometers that have been optimized for cosmic microwave background (CMB) observations. In a 64-channel demonstration, we show that the μmux produces a white, input referred current noise level of 29 pA/ √{H z } at a microwave probe tone power of -77 dB, which is well below the expected fundamental detector and photon noise sources for a ground-based CMB-optimized bolometer. Operated with negligible photon loading, we measure 98 pA/ √{H z } in the TES-coupled channels biased at 65% of the sensor normal resistance. This noise level is consistent with that predicted from bolometer thermal fluctuation (i.e., phonon) noise. Furthermore, the power spectral density is white over a range of frequencies down to ˜100 mHz, which enables CMB mapping on large angular scales that constrain the physics of inflation. Additionally, we report cross-talk measurements that indicate a level below 0.3%, which is less than the level of cross-talk from multiplexed readout systems in deployed CMB imagers. These measurements demonstrate the μmux as a viable readout technique for future CMB imaging instruments.

  17. Dehydrating of flax fiber with microwave heating for biocomposite production.

    Science.gov (United States)

    Panigrahi, Satyanarayan; Ghazanfari, Ahmad; Meda, Venkatesh

    2006-01-01

    The feasibility of microwave dehydrating flax fiber was evaluated using a commercial domestic microwave oven at four power settings representing 200, 300, 400 and 500 Watt (W) power level. Due to the possibility of local heating and consequent fiber degradation, the changes in color of the flax fiber at different levels of temperature were also investigated. The dehydration processes at various power levels were simulated by Page model. Based on visual inspection, color analysis and scanning electron microscopy (SEM) of the fiber, it was revealed that discoloration of the fiber occurred at about 170 degrees C. At 200 and 300 W power level, after 10 minutes of dehydrating, the moisture content of the fiber reached from initial 7.9% close to 2.0 and 1.0%, respectively. For 400 W power level, the moisture content of the fiber dropped to 0. 10% in about 9.5 minutes. Major discoloration of the fiber was noticed when dehydration was proceed beyond 4.5 minutes for 500 W treatment. The Page model very well fitted the experimental data. The coefficients of determination calculated from the model and the experimental data increased with increase in applied microwave power

  18. Microwave hydrology: A trilogy

    Science.gov (United States)

    Stacey, J. M.; Johnston, E. J.; Girard, M. A.; Regusters, H. A.

    1985-01-01

    Microwave hydrology, as the term in construed in this trilogy, deals with the investigation of important hydrological features on the Earth's surface as they are remotely, and passively, sensed by orbiting microwave receivers. Microwave wavelengths penetrate clouds, foliage, ground cover, and soil, in varying degrees, and reveal the occurrence of standing liquid water on and beneath the surface. The manifestation of liquid water appearing on or near the surface is reported by a microwave receiver as a signal with a low flux level, or, equivalently, a cold temperature. Actually, the surface of the liquid water reflects the low flux level from the cosmic background into the input terminals of the receiver. This trilogy describes and shows by microwave flux images: the hydrological features that sustain Lake Baykal as an extraordinary freshwater resource; manifestations of subsurface water in Iran; and the major water features of the Congo Basin, a rain forest.

  19. Stabilized γ-BIMNVOX solid electrolyte: Ethylene glycol–citrate sol–gel synthesis, microwave-assisted calcination, and structural and electrical characterization

    Energy Technology Data Exchange (ETDEWEB)

    Al-Areqi, Niyazi A.S., E-mail: niyazi.alareqi@gmail.com [Department of Chemistry, Faculty of Applied Science, Taiz University, Taiz, Republic of Yemen (Yemen); Beg, Saba [Department of Chemistry, Aligarh Muslim University, Aligarh 202002 (India); Al-Alas, Ahlam [Department of Chemistry, Faculty of Applied Science, Taiz University, Taiz, Republic of Yemen (Yemen); Hafeez, Shehla [Department of Chemistry, Aligarh Muslim University, Aligarh 202002 (India)

    2013-12-25

    Highlights: •γ-BIMNVOX was synthesized by ethylene glycol–citrate sol–gel route. •γ-BIMNVOX crystallizes by 25-min microwave-assisted calcination. •Smaller particle sizes for microwave calcined BIMNVOX samples. •Best oxide-ion performance for microwave calcined BIMNVOX samples. -- Abstract: Samples of γ-BIMNVOX (Bi{sub 2}V{sub 1−x}Mn{sub x}O{sub 5.5−x/2}; 0.13 ⩽ x ⩽ 0.20) system were synthesized by an ethylene glycol–citrate sol–gel route. The resulting xerogels were then calcined by the microwave heating using a modified domestic microwave oven operated at 2.45 GHz. Microwave-assisted calcination samples in comparison with other conventionally calcined samples were characterized in terms of phase crystallization, stabilization and particle size using simultaneous thermogravimetric–differential thermal analysis (TG–DTA), X-ray powder diffraction (XRPD) and scanning electron microscopy (SEM). The AC impedance spectroscopy was employed for electrical characterization. It was found that the microwave-assisted calcination route successfully produces better crystalline stabilized γ-BIMNVOX samples with appreciably small average particle sizes after only 25 min of microwave heating. The electrical properties of microwave calcined γ-BIMNVOX system make it an advanced low-temperature solid electrolyte suitable for use in oxide-ion based electrochemical applications.

  20. Cavity Microwave Searches for Cosmological Axions

    CERN Multimedia

    CERN. Geneva

    2005-01-01

    The lecture will cover the searches for dark matter axions based on the microwave cavity experiment of Sikivie. The topics will begin with a brief overview of halo dark matter, and the axion as a candidate. The principle of resonant conversion of axions in an external magnetic field will be described, and practical considerations in optimizing the experiment as a signal-to-noise problem. A major focus of the lecture will be the two complementary strategies for ultra-low noise detection of the microwave photons - the "photon-as-wave" approach (i.e. conventional heterojunction amplifiers and soon quantum-limited SQUID devices), and "photon-as-particle" (i.e. Rydberg-atom single-quantum detection). Experimental results will be presented; these experiments have already reached well into the range of sensitivity to exclude plausible axion models, for limited ranges of mass. The lecture will conclude with a discussion of future plans and challenges for the microwave ca...

  1. Microwave digestion and mass spectrometry – useful tools in heavy metals determination

    Directory of Open Access Journals (Sweden)

    BURADA Adrian

    2010-09-01

    Full Text Available The quality indicators of Danube Delta lakes are established according with the Romanian Normative 161 / 2006. The sampling points are: Somova, Fortuna, Nebunu, Merhei, Miazazi, Erenciuc, Uzlina, Isac. The selected heavy metals are: arsenic, cadmium, nickel, lead. First the samples were digested at the microwave oven, and then there were analyzed at the ICPMS. The arsenic concentrations are under the limit in all selected lakes in 2007 and2008, except for Uzlina, in 2008. In general, the cadmium, nickel and lead concentrations exceed the values for the secondquality boundary.

  2. Determination of nitrate in lettuce by ion chromatography after microwave water extraction

    Directory of Open Access Journals (Sweden)

    Humberto Brevilato Novaes

    2009-01-01

    Full Text Available Lettuce is worldwide known as the most important vegetable. In this context, most farmers are searching new techniques for best quality products including hydropony. However, nitrate is of great concern, since it has a negative impact on human metabolism. The main objective of the present work was to evaluate the nitrate content of lettuce produced by conventional and hydroponic systems. The determination was conducted by ion chromatography and a new method of extraction was tested using microwave oven digestion. The results indicated that nitrate level produced in the conventional system was lower than in the hydroponic system.

  3. Green chemistry: Efficient epoxides ring-opening with 1-butanol under microwave irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Vidal, Jesus A. [Departamento de Quimica Inorganica, Facultad de Ciencias, Universidad de Extremadura, Campus Universitario, Avda. de Elvas, s/n, E-06071-Badajoz (Spain); Duran-Valle, Carlos J. [Departamento de Quimica Inorganica, Facultad de Ciencias, Universidad de Extremadura, Campus Universitario, Avda. de Elvas, s/n, E-06071-Badajoz (Spain)]. E-mail: carlosdv@unex.es; Ferrera-Escudero, Santiago [Departamento de Quimica Inorganica y Quimica Tecnica, Universidad Nacional de Educacion a Distancia, C/Senda del Rey, 9, E-28040 Madrid (Spain)

    2006-06-30

    Two activated carbons treated with mineral acids (HNO{sub 3} and sulfonitric mixture) have been tested as acid catalysts in the epoxides (1,2-epoxyhexane and styrene oxide) ring-opening reaction with 1-butanol under microwave (MW) irradiation. The mayor obtained product is that resulting of the alcohol addition to the most substituted carbon in the epoxide ring. The most active catalyst is that treated with sulfonitric mixture. The use of a MW oven allows achieving to the complete conversion of styrene oxide in only 2 min.

  4. 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.

  5. Rapid detection of t(15;17)(q24;q21) in acute promyelocytic leukaemia by microwave-assisted fluorescence in situ hybridization.

    Science.gov (United States)

    Soriani, Silvia; Mura, Cinzia; Panico, Anna Rita; Scarpa, Anna Maria; Recchimuzzo, Patrizia; Dadati, Raffaella; Farioli, Renata; De Canal, Gabriella; Mura, Maria Angela; Cesana, Clara

    2017-03-01

    Acute promyelocytic leukaemia (APL) is a hematologic malignancy characterized by the rearrangement of the PML and RARα genes, mostly due to a reciprocal chromosomal translocation t(15;17)(q24;q21). A quick APL diagnosis is essential for starting a prompt suitable therapy. We describe a new rapid diagnostic laboratory approach to detect the PML-RARα rearrangement, which gives clear genetic results within 30 min of hybridization. It combines quick cell harvesting, fluorescence in situ hybridization performed with commercial DNA probe and microwave beams supplied by a domestic microwave oven. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  6. The rapid formation of tin oxide pillared laponite by microwave heating: Characterisation by tin-119 Mössbauer spectroscopy, X-ray photoelectron spectroscopy and nuclear magnetic resonance

    Science.gov (United States)

    Berry, Frank J.; Ashcroft, R. Claire; Beevers, Martin S.; Bond, Stephen P.; Gelders, Andrew; Lawrence, Monique A. M.; McWhinnie, William R.

    1992-04-01

    The intercalation of organotin-compounds into laponite and the formation of tin(IV) oxide pillars is rapidly achieved when performed in a microwave oven.119Sn Mössbauer- and x-ray- photoelectron-spectroscopy suggest that Ph3SnCl and Ph2SnCl2 undergo hydrolysis on the surface once sorbed. The treatment of Ph3SnCl/laponite with microwave radiation also induces the formation of a metallic phase which contains both tin and magnesium.

  7. 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

  8. Microwave coupler and method

    Science.gov (United States)

    Holcombe, C. E.

    1984-11-01

    The present invention is directed to a microwave coupler for enhancing the heating or metallurgical treatment of materials within a cold-wall, rapidly heated cavity as provided by a microwave furnace. The coupling material of the present invention is an alpha-rhombohedral-boron-derivative-structure material such as boron carbide or boron silicide which can be appropriately positioned as a susceptor within the furnace to heat other material or be in powder particulate form so that composites and structures of boron carbide such as cutting tools, grinding wheels and the like can be rapidly and efficiently formed within microwave furnaces.

  9. 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

  10. Dielectric properties, optimum formulation and microwave baking conditions of chickpea cakes.

    Science.gov (United States)

    Alifakı, Yaşar Özlem; Şakıyan, Özge

    2017-03-01

    The aim of this study was to correlate dielectric properties with quality parameters, and to optimize cake formulation and baking conditions by response surface methodology. Weight loss, color, specific volume, hardness and porosity were evaluated. The samples with different DATEM (0.4, 0.8 and 1.2%) and chickpea flour concentrations (30, 40 and 50%) were baked in microwave oven at different power (300, 350, 400 W) and baking times (2.50, 3.0, 3.50 min). It was found that microwave power showed significant effect on color, while baking time showed effect on weight loss, porosity, hardness, specific volume and dielectric properties. Emulsifier level affected porosity, specific volume and dielectric constant. Chickpea flour level affected porosity, color, hardness and dielectric properties of cakes. The optimum microwave power, baking time, DATEM level and chickpea flour level were found as 400 W, 2.84 min, 1.2% and 30%, respectively. The comparison between conventionally baked and the microwave baked cakes at optimum points showed that color difference, weight loss, specific volume and porosity values of microwave baked cakes were less than those of conventionally baked cakes, on the other hand, hardness values were higher. Moreover, a negative correlation between dielectric constant and porosity, and weight loss values were detected for microwave baked samples. A negative correlation between dielectric loss factor and porosity was observed. These correlations indicated that quality characteristics of a microwave baked cake sample can be assessed from dielectric properties. These correlations provides understanding on the behavior of food material during microwave processing.

  11. Association of polycyclic aromatic hydrocarbons metabolites and risk of diabetes in coke oven workers.

    Science.gov (United States)

    Yang, Liangle; Yan, Kai; Zeng, Dan; Lai, Xuefeng; Chen, Xuguang; Fang, Qin; Guo, Huan; Wu, Tangchun; Zhang, Xiaomin

    2017-04-01

    Elevated polycyclic aromatic hydrocarbons (PAHs) metabolites have recently been linked to increased risk of diabetes in the general population, but little is known about the risk of diabetes due to high pollution levels of PAHs exposure. We aimed to examine whether occupational exposure to PAHs would be one of the important risk factors for diabetes in the coke oven workers. A total of 1472 coke oven workers with complete data were qualified for the present study. We measured 12 urinary monohydroxy polycyclic aromatic hydrocarbons (OH-PAHs) by gas chromatography-mass spectrometry (GC-MS). Multiple logistic regression was used to evaluate the associations between urinary OH-PAHs and risk of diabetes, with adjustment for the potential confounders. We found that elevated urinary 4-hydroxyphenanthrene (4-OHPh) was significantly associated, in a dose-dependent manner, with increased risk of diabetes (Ptrend = 0.003). Compared with individuals with 4-OHPh in the lowest quartile, the adjusted odds ratio (OR) of diabetes among those in the highest quartile was 2.80 (95% CI = 1.37-5.71). In stratified analysis, the association was more prominent in those who were smokers, overweight (BMI ≥24 kg/m2), with longer working years (≥20 years) and worked at coke oven settings. In addition, high levels of 4-OHPh combined with longer working years or overweight had a joint effect on the risk of diabetes. Our data suggested that elevated 4-OHPh was dose-responsive associated with increased risk of diabetes in the coke oven workers. The risk assessment of diabetes related to occupational PAHs exposure should take working years and BMI into consideration. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. ONE-STEP CONVERSION OF EUGENOL TO METHYL ISOEUGENOL USING MICROWAVE IRRADIATION IN SOLVENT-FREE CONDITIONS

    Directory of Open Access Journals (Sweden)

    Marcellino Rudyanto

    2010-06-01

    Full Text Available A research on conversion of eugenol to methyl isoeugenol via one-step reaction with microwave irradiation has been carried out. Mixtures containing eugenol, sodium or potassium carbonate as solid support, with or without sodium or potassium hydroxide as base, with or without tetrabutylammonium bromide as phase transfer catalyst, with dimethyl sulfate as the methylating agent were irradiated in a domestic microwave oven for 20 - 50 seconds. It was revealed that one-step methylation and isomerization required combinations of sodium or potassium hydroxide base and tetrabutylammonium bromide. Without combination of base and TBAB only one product, i.e. methyl eugenol, was formed.   Keywords: eugenol, methyl eugenol, methyl isoeugenol, microwave

  13. Microwave assisted synthesis and characterization of unsymmetrical tetradentate Schiff base complexes of VO(IV) and MoO(V)

    Science.gov (United States)

    Thaker, B. T.; Barvalia, R. S.

    2011-12-01

    Microwave synthesis, is green chemical method, simple, sensitive, reducing solvent amount and reaction time. The attempt was made to synthesize the unsymmetrical tetradentate N 2O 2 ligands and their VO(IV) and MoO(V) unsymmetrical tetradentate Schiff base complexes by classical and microwave techniques using domestic microwave oven. The resulting unsymmetrical Schiff base ligands L 1-L 3 characterized by different spectral methods. Their complexes with oxocations of VO(IV) and MoO(V) have been synthesized and characterized by elemental analyses, conductometric measurements, infrared and electronic absorption, 1H NMR spectra, mass spectrometry, ESR spectra, magnetic susceptibility measurement and thermal study. The study suggests that the oxo metal ion is bonded to the ligand through the oxygen and imino nitrogen and the geometry around metal ion is distorted octahedral.

  14. Demonstration of tunable microwave photonic notch filters using slow and fast light effects in semiconductor optical amplifiers

    DEFF Research Database (Denmark)

    Xue, Weiqi; Sales, Salvador; Mørk, Jesper

    2009-01-01

    We introduce a novel scheme based on slow and fast light effects in semiconductor optical amplifiers, to implement a microwave photonic notch filter with ~100% fractional tuning range at a microwave frequency of 30 GHz.......We introduce a novel scheme based on slow and fast light effects in semiconductor optical amplifiers, to implement a microwave photonic notch filter with ~100% fractional tuning range at a microwave frequency of 30 GHz....

  15. Carbon dioxide emission in hydrogen production technology from coke oven gas with life cycle approach

    Directory of Open Access Journals (Sweden)

    Burmistrz Piotr

    2016-01-01

    Full Text Available The analysis of Carbon Footprint (CF for technology of hydrogen production from cleaned coke oven gas was performed. On the basis of real data and simulation calculations of the production process of hydrogen from coke gas, emission indicators of carbon dioxide (CF were calculated. These indicators are associated with net production of electricity and thermal energy and direct emission of carbon dioxide throughout a whole product life cycle. Product life cycle includes: coal extraction and its transportation to a coking plant, the process of coking coal, purification and reforming of coke oven gas, carbon capture and storage. The values were related to 1 Mg of coking blend and to 1 Mg of the hydrogen produced. The calculation is based on the configuration of hydrogen production from coke oven gas for coking technology available on a commercial scale that uses a technology of coke dry quenching (CDQ. The calculations were made using ChemCAD v.6.0.2 simulator for a steady state of technological process. The analysis of carbon footprint was conducted in accordance with the Life Cycle Assessment (LCA.

  16. Information exchange about installation of a fifth oven for paste regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Schappert

    1943-10-20

    Schappert documented a discussion relating to a prior meeting about the aspects of adding a fifth oven to a series of ovens to take the burden off preheaters in the liquid phase. Saving energy was the uppermost consideration in adding the new equipment, which according to Schappert, would amortize itself in a short while. He reiterated that, by lowering temperatures, the preheaters would not be over-burdened, an equalization in temperature could be obtained, and no deterioration problems would occur. Also, he pointed out that, with the temperature drop, a new chamber could be charged correspondingly higher, providing the pumps sufficed and resistance permitted, if one gradually reduced the through-put with the increase of incrustation in the preheater. Thus, the fifth oven would pay for itself in diversified ways. Also, it was suggested that plants which so far did not use paste regeneration should introduce it if possible. Finally, it was suggested that plants having regeneration already should add an extra gas regenerator at the coolest position to give more heat there.

  17. Proposal to eliminate caviar-residue in ovens by analogous occurrences in other equipment

    Energy Technology Data Exchange (ETDEWEB)

    Moll

    1944-05-03

    The idea was that, since the water vapor in the ovens under normal conditions was kept fluid at 700 atmospheres/450/sup 0/C, the inorganic salts would dissolve. This proposal was based on information published in a couple of technical journals and observations of silicification of turbine blades in steam turbine operations and quartz veins in geological formations. The articles dealt with solubility of salts such as BaCl/sub 2/, KCl, Na/sub 2/SO/sub 4/, and NaOH. Unfortunately, measurements stopped in the area of critical pressure. Results purported, however, that inorganic salts, rather concentrated, were soluble by highly superheated steam, and solubility improved as pressure increased. It was anticipated that this process could be applied to hydrogenation ovens since there was water present in the operation. Proposed was researching a method of getting the salts to form a mud instead of crystallizing and precipitating into the oven. The writer said that research should be conducted since high pressure techniques were available as well as required apparatus.

  18. Optimisation of microwave-assisted processing in production of pineapple jam

    Science.gov (United States)

    Ismail, Nur Aisyah Mohd; Abdullah, Norazlin; Muhammad, Norhayati

    2017-10-01

    Pineapples are available all year round since they are unseasonal fruits. Due to the continuous harvesting of the fruit, the retailers and farmers had to find a solution such as the processing of pineapple into jam, to treat the unsuccessfully sold pineapples. The direct heating of pineapple puree during the production of pineapple jam can cause over degradation of quality of the fresh pineapple. Thus, this study aims to optimise the microwave-assisted processing conditions for producing pineapple jam which could reduce water activity and meets minimum requirement for pH and total soluble solids contents of fruit jam. The power and time of the microwave processing were chosen as the factors, while the water activity, pH and total soluble solids (TSS) content of the pineapple jam were determined as responses to be optimised. The microwave treatment on the pineapple jam was able to give significant effect on the water activity and TSS content of the pineapple jam. The optimum power and time for the microwave processing of pineapple jam is 800 Watt and 8 minutes, respectively. The use of domestic microwave oven for the pineapple jam production results in acceptable pineapple jam same as conventional fruit jam sold in the marketplace.

  19. Microstructural and mechanical investigation of aluminium alloy (Al 1050) melted by microwave hybrid heating

    Science.gov (United States)

    Shashank Lingappa, M.; Srinath, M. S.; Amarendra, H. J.

    2017-07-01

    Microwave processing of metals is an emerging area. Melting of bulk metallic materials through microwave irradiation is still immature. In view of this, the present paper discusses the melting of bulk Al 1050 metallic material through microwave irradiation. The melting process is carried out successfully in a domestic microwave oven with 900 W power at 2450 MHz frequency. Metallurgical and mechanical characterization of the processed and as-received material is carried out. Aluminium phase is found to be dominant in processed material when tested through x-ray diffraction (XRD). Microstructure study of as-cast metal through scanning electron microscopy (SEM) reveals the formation of uniform hexagonal grain structure free from pores and cavities. The average tensile strength of the cast material is found to be around 21% higher, when compared to as-received material. Vickers’ microhardness of the as-cast metal is measured and is 10% higher than that of the as-received metal. Radiography on as-cast metal shows no significant defects. Al 1050 material melted through microwave irradiation has exhibited superior properties than the as-received Al 1050.

  20. Microwave Irradiation Induced Effects to Single-walled Carbon Nanotube Thin Films

    Science.gov (United States)

    Wang, Lu; Xiong, Yao; Wu, Ziran; Chen, Liwei; Xin, Hao

    2009-03-01

    Carbon nanotubes have been considered as potential building blocks for nano-scale circuits in virtue of their unique mechanical and electrical properties. However, one of the biggest obstacles for massive production of nanotube circuits is the difficulty of separating semiconducting tubes from metallic tubes or vice versa. In this work, a convenient method which may be potentially employed to selectively remove metallic tubes using microwave induced breakdown is proposed and investigated. Carbon nanotube thin films deposited on glass and quartz substrates are placed in a commercial microwave oven and heated for up to several minutes. The radial breathing mode in Raman spectra on the nanotube samples before and after the microwave irradiation suggests that the metallic-to-semiconducting ratios are reduced by around 20%. Meanwhile, because in the thin film samples most of the nanotubes are entangled, smaller diameter nanotubes (both metallic and semiconducting) tend to be affected more. THz transmission measurements of these thin films are also performed before and after microwave irradiation. The significant increase of transmission after the microwave irradiation process confirms the loss of metallic tubes.

  1. Emitron: microwave diode

    Science.gov (United States)

    Craig, G.D.; Pettibone, J.S.; Drobot, A.T.

    1982-05-06

    The invention comprises a new class of device, driven by electron or other charged particle flow, for producing coherent microwaves by utilizing the interaction of electromagnetic waves with electron flow in diodes not requiring an external magnetic field. Anode and cathode surfaces are electrically charged with respect to one another by electron flow, for example caused by a Marx bank voltage source or by other charged particle flow, for example by a high energy charged particle beam. This produces an electric field which stimulates an emitted electron beam to flow in the anode-cathode region. The emitted electrons are accelerated by the electric field and coherent microwaves are produced by the three dimensional spatial and temporal interaction of the accelerated electrons with geometrically allowed microwave modes which results in the bunching of the electrons and the pumping of at least one dominant microwave mode.

  2. 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...

  3. The Cosmic Microwave Background

    Science.gov (United States)

    Pierpaoli, E.

    2011-03-01

    In these lectures I present the physical aspects of the Cosmic Microwave Background primary and secondary anisotropies; the characteristics of the CMB power spectra and their dependence on cosmological parameters. I also discuss the observational status and future perspectives.

  4. Swarm Optimization Methods in Microwave Imaging

    Directory of Open Access Journals (Sweden)

    Andrea Randazzo

    2012-01-01

    Full Text Available Swarm intelligence denotes a class of new stochastic algorithms inspired by the collective social behavior of natural entities (e.g., birds, ants, etc.. Such approaches have been proven to be quite effective in several applicative fields, ranging from intelligent routing to image processing. In the last years, they have also been successfully applied in electromagnetics, especially for antenna synthesis, component design, and microwave imaging. In this paper, the application of swarm optimization methods to microwave imaging is discussed, and some recent imaging approaches based on such methods are critically reviewed.

  5. Fundamentals of RF and microwave transistor amplifiers

    CERN Document Server

    Bahl, Inder J

    2009-01-01

    A Comprehensive and Up-to-Date Treatment of RF and Microwave Transistor Amplifiers This book provides state-of-the-art coverage of RF and microwave transistor amplifiers, including low-noise, narrowband, broadband, linear, high-power, high-efficiency, and high-voltage. Topics covered include modeling, analysis, design, packaging, and thermal and fabrication considerations. Through a unique integration of theory and practice, readers will learn to solve amplifier-related design problems ranging from matching networks to biasing and stability. More than 240 problems are included to help read

  6. Microwave Generation in Synchronized Semiconductor Superlattices

    Science.gov (United States)

    Gaifullin, M. B.; Alexeeva, N. V.; Hramov, A. E.; Makarov, V. V.; Maksimenko, V. A.; Koronovskii, A. A.; Greenaway, M. T.; Fromhold, T. M.; Patanè, A.; Mellor, C. J.; Kusmartsev, F. V.; Balanov, A. G.

    2017-04-01

    We study high-frequency generation in a system of electromagnetically coupled semiconductor superlattices fabricated on the same doped substrate. Applying a bias voltage to a single superlattice generates high-frequency current oscillations. We demonstrate that within a certain range of the applied voltage, the current oscillations within the superlattices can be self-synchronized, which leads to a dramatic rise in the generated microwave power. These results, which are in good agreement with our numerical model, open a promising practical route towards the design of high-power miniature microwave generators.

  7. 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

  8. Microwave Processing of Materials

    Science.gov (United States)

    1994-01-01

    reactions in sol-gel processing, gas-phase synthesis , solution evaporation/decomposition, or hydrothermal reactions. Each of these, and other powder... synthesis methods, will be described next. Sol-Gel Decomposition/Drying Microwaves have been used in several of the processing stages to synthesize BaTiO3 ...high surface areas (10-700 m2/g). Hydrothermal Reactions Microwave- hydrothermal processing has been utilized in catalyzing the synthesis of crystalline

  9. Assessment of potential damage to DNA in urine of coke oven workers: an assay of unscheduled DNA synthesis.

    OpenAIRE

    Roos, F; Renier, A; Ettlinger, J; Iwatsubo, Y; Letourneux, M; Haguenoer, J M; Jaurand, M C; Pairon, J C

    1997-01-01

    OBJECTIVES: A study was conducted in coke oven workers to evaluate the biological consequences of the exposure of these workers, particularly production of potential genotoxic factors. METHODS: 60 coke oven workers and 40 controls were recruited in the same iron and steel works. Exposure to polycyclic aromatic hydrocarbons (PAHs) was assessed by job and measurement of 1-hydroxypyrene (1OHP) in urine samples. An unscheduled DNA synthesis assay was performed on rat pleural mesothelial cells use...

  10. Microwave regenerated particulate trap

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, A.C. Jr.; Yonushonis, T.M. [Cummins Engine Co., Inc., Columbus, IN (United States); Haberkamp, W.C.; Mako, F.; Len, L.K,; Silberglitt, R.; Ahmed, I. [FM Technologies, Inc., Fairfax, VA (United States)

    1997-12-31

    It has been demonstrated that a fibrous particulate filter can extract particulate matter from the diesel exhaust. However, additional engineering efforts remains to achieve the design target of 90%. It has also be shown that with minor modifications magnetrons produced for home ovens can endure a simulated diesel operating environment. Much work remains to develop a robust product ready to complete extensive engine testing and evaluation. These efforts include: (1) additional environmental testing of magnetrons; (2) vibration testing of the filter in the housing; (3) evaluating alternative methods/designs to seal the center bore; and (4) determining the optimum coating thickness that provides sufficient structural integrity while maintaining rapid heating rates.

  11. Producing ashless coal extracts by microwave irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ozgur Sonmez; Elife Sultan Giray [Mersin University, Mersin (Turkey). Department of Chemistry

    2011-06-15

    To produce ashless coal extracts, three Turkish coals were extracted with N-methyl-2-pyrrolidinone (NMP), NMP/ethylenediamine (EDA) (17/1, vol/vol) mixture and NMP/tetralin (9/1, vol/vol) mixture through thermal extraction and microwave extraction. Solvent extraction by microwave irradiation (MI) was found to be more effective than that by thermal extraction. Extraction yield of coals in NMP enhanced by addition of a little EDA, but tetralin addition showed variances according to extraction method used. While tetralin addition caused a decrease in the thermal extraction yield, it increased the yield of the extraction by MI. Following the extraction, the solid extracts were produced with ash content ranging from 0.11% to 1.1%. Ash content of solid extract obtained from microwave extraction are less than ash contents of solid extracts obtained from thermal extraction. 34 refs., 7 figs., 5 tabs.

  12. Intracity Quantum Communication via Thermal Microwave Networks

    Science.gov (United States)

    Xiang, Ze-Liang; Zhang, Mengzhen; Jiang, Liang; Rabl, Peter

    2017-01-01

    Communication over proven-secure quantum channels is potentially one of the most wide-ranging applications of currently developed quantum technologies. It is generally envisioned that in future quantum networks, separated nodes containing stationary solid-state or atomic qubits are connected via the exchange of optical photons over large distances. In this work, we explore an intriguing alternative for quantum communication via all-microwave networks. To make this possible, we describe a general protocol for sending quantum states through thermal channels, even when the number of thermal photons in the channel is much larger than 1. The protocol can be implemented with state-of-the-art superconducting circuits and enables the transfer of quantum states over distances of about 100 m via microwave transmission lines cooled to only T =4 K . This opens up new possibilities for quantum communication within and across buildings and, consequently, for the implementation of intracity quantum networks based on microwave technology only.

  13. Magnetization switching by current and microwaves

    Science.gov (United States)

    Taniguchi, Tomohiro; Saida, Daisuke; Nakatani, Yoshinobu; Kubota, Hitoshi

    2016-01-01

    We propose a theoretical model of magnetization switching in a ferromagnetic multilayer by both electric current and microwaves. The electric current gives a spin transfer torque on the magnetization, while the microwaves induce a precession of the magnetization around the initial state. Based on numerical simulation of the Landau-Lifshitz-Gilbert (LLG) equation, it is found that the switching current is significantly reduced compared with the switching caused solely by the spin transfer torque when the microwave frequency is in a certain range. We develop a theory of switching from the LLG equation averaged over a constant energy curve. It was found that the switching current should be classified into four regions, depending on the values of the microwave frequency. Based on the analysis, we derive an analytical formula of the optimized frequency minimizing the switching current, which is smaller than the ferromagnetic resonance frequency. We also derive an analytical formula of the minimized switching current. Both the optimized frequency and the minimized switching current decrease with increasing the amplitude of the microwave field. The results will be useful to achieve high thermal stability and low switching current in spin torque systems simultaneously.

  14. Association between urinary 1-hydroxypyrene and genotoxic effects in coke oven workers.

    Science.gov (United States)

    Siwińska, E; Mielzyńska, D; Kapka, L

    2004-03-01

    To investigate whether current occupational exposure of coke oven workers to polycyclic aromatic hydrocarbons (PAHs) results in genotoxic effects measured in peripheral blood lymphocytes and whether these biomarkers are associated with the biomarkers of exposure. Blood and urine samples were collected immediately after a shift at the end of a working week from 50 coke oven workers and 50 control workers not exposed to PAHs. Methods included: (1) biomarkers of exposure: urinary 1-hydroxypyrene (HpU), urinary mutagenicity by the plate Salmonella test with strains TA98 and YG1024 after metabolic activation, expressed as mutagenic rate (MR98 and MR1024, respectively), urinary cotinine; and (2) biomarkers of biological effects in peripheral blood lymphocytes (PBL): sister chromatid exchanges (SCE/cell), cells of high frequency of SCE (% HFC), micronuclei (MN/1000 cells), chromosomal aberrations (CA/100 cells), and DNA damage by the Comet assay. Occupational exposure to PAH resulted in significantly increased levels of HpU and mutagenic effect of urine. Median values of these biomarkers in coke oven workers were: 9.0 micromol/mol creatinine for HpU, 2.7 for MR98, and 8.2 for MR1024, compared to the controls: HpU = 0.6 micromol/mol creatinine, MR98 = 1.2, and MR1024 = 5.5. Occupational exposure caused significant induction of SCE, HFC, and MN in coke oven workers: median SCE = 5.9, HFC = 12.0%, MN = 6.0 compared to the controls: 3.9, 5.0%, and 3.0, respectively. No effect of occupational exposure was found in relation to CA and DNA damage measured with the Comet assay. HpU concentration was positively associated with SCE and HFC. The concentration of urinary 1-hydroxypyrene corresponding to a 5% probability of increased SCE was 1.0 micromol/mol creatinine. The occupational exposure to PAHs resulted in measurable biological effects (SCE, HFC, MN). In coke oven workers an increased level of SCE was not observed below the level of 1.0 micromol HpU/mol creatinine.

  15. Comparative study between microwave and conventional dehydration of okra.

    Directory of Open Access Journals (Sweden)

    Shams El Din, M. H. A.

    1999-12-01

    Full Text Available This study was conducted to evaluate different pre-treatments and dehydration methods on the quality of okra. No significant differences were found among pretreatments and dehydration methods for the chemical composition of dehydrated okra samples. Dipping in 0.1 % sodium metabisulphite solution at room temperature and immersion in 0.1 % sodium metabisulphite solution at 92-95 °C improved the retention of ascorbic acid of okra samples after dehydration by either conventional or microwave oven. Also, the reduced dehydration time required for microwave dehydration produced far less destruction of ascorbic acid. The highest rehydration ratio was found in unwashed okra sample and dehydrated by microwave after immersion in 0.1 % sodium metabisulphite solution at 92-95 °C. Dehydrated okra samples by sun drying and conventional oven had lower retention percentages of total chlorophyll and carotenoids than those of dehydrated okra samples by microwave oven. The general appearance and colour scores of dehydrated okra samples by microwave were significantly different from those of conventionally dehydrated or sun dried okra samples.

    Este estudio se ha realizado para evaluar los diferentes pretratamientos y métodos de deshidratación en la calidad del kimbombó. No se encontraron diferencias significativas entre ellos respecto a la composición química de las muestras de kimbombó deshidratadas. La inmersión en solución de metabisulfito sódico al 0.1 % a temperatura ambiente y la inmersión en solución de metabisulfito sódico al 0.1 % a 92-95 °C mejoraron la retención de ácido ascórbico de las muestras de kimbombó después de la deshidratación tanto utilizando el homo convencional como el horno microondas. Además el menor tiempo necesario para la deshidratación usando el horno microondas produjo menos destrucción de ácido ascórbico. La mayor relación de rehidratación fue encontrada en muestras de kimbombó no tratadas o

  16. The influence of microwave irradiation on rocks for microwave-assisted underground excavation

    Directory of Open Access Journals (Sweden)

    Ferri Hassani

    2016-02-01

    Full Text Available Demand is growing for explosive-free rock breakage systems for civil and mining engineering, and space industry applications. This paper highlights the work being undertaken in the Geomechanics Laboratory of McGill University to make a real application of microwave-assisted mechanical rock breakage to full-face tunneling machines and drilling. Comprehensive laboratory tests investigated the effect of microwave radiation on temperature profiles and strength reduction in hard rocks (norite, granite, and basalt for a range of exposure times and microwave power levels. The heating rate on the surface of the rock specimens linearly decreased with distance between the sample and the microwave antenna, regardless of microwave power level and exposure time. Tensile and uniaxial compressive strengths were reduced with increasing exposure time and power level. Scanning electron micrographs (SEMs highlighted fracture development in treated basalt. It was concluded that the microwave power level has a strong positive influence on the amount of heat damage induced to the rock surface. Numerical simulations of electric field intensity and wave propagation conducted with COMSOL Multiphysics® software generated temperature profiles that were in close agreement with experimental results.

  17. Energy efficient microwave heating of carbon fibre reinforced plastic; Energieeffiziente Mikrowellentemperierung von kohlenstofffaserverstaerkten Duroplasten

    Energy Technology Data Exchange (ETDEWEB)

    Danilov, Maksim

    2013-07-01

    The polymerization of carbon fiber reinforced thermosetting composites (CFRP) is a dull process step with high energy requirements within the production chain. His improvement would affect the economic and ecological balance of the fiber reinforced materials in a positive way. One possible approach investigated here is tempering of raw materials in a microwave oven. In this work the material to be processed - a carbon fiber-reinforced plastic laminate - is being characterized in the microwave field through electromagnetic and thermal parameters. The relationship between its design parameters (fiber orientation and number of layers), the energy levels (reflection, absorption and transmittance) and the thermal process parameters (temperature gradient achievable) will be established. Afterwards, constructive options will be examined and evaluated which are suitable to install a low-loss (both by means of wave reflections and heat losses) industrial process.

  18. Monitoring and control system for tuneable high frequency microwave assisted chemistry

    Science.gov (United States)

    Lewis, G. P.; Wylie, S. R.; Shaw, A.; Al-Shamma'a, A. I.; Phipps, D.; Alkhaddar, R.; Bond, G.

    2007-07-01

    Microwave chemistry is an established technique in the synthesis of organic compounds at a frequency of 2.45 GHz. This is considered to be a result of the development of microwave ovens, rather than an objective solution, which maximises efficiency through careful selection of the operating frequency. To obtain a frequency for a dielectric, the complex permittivity should be determined as a function of frequency. If the correct heating frequency is found, superheating can occur when a liquid solvent reaches its boiling point and exceeds it. This paper presents sensor diodes and temperature sensors used in a mono-mode reactor, with computer control of an E-H tuner, frequency and incident power to control temperature and power, experimental results showing heating and reactions using ethanol are reported.

  19. RESEARCH OF MICROWAVE DRYING OF NATURAL ZEOLITE GRANULES AND ITS INFLUENCE ON THE TECHNOLOGICAL PROPERTIES

    Directory of Open Access Journals (Sweden)

    Rybachuk V.D.

    2016-06-01

    Full Text Available Introduction. The wet granulation technique is often used in the preparation of free-flowing granules in the manufacture of tablets and capsules. It is very important that granules obtained by this technology be dried before further processing. And also, it is important that the method of drying is entirely controlled and managed and the result is quite predictable. In recent years, microwave drying of granules make a considerable interest. Microwave drying is especially useful for moisture sensitive materials which are mostly pharmaceutical substances. Microwave drying technology is useful for dosage forms with high purity, since this method provides the possibility of drying in the same container production, which reduces the chance of cross contamination of matter and its direct contact with staff. The aim of this work was to study the effect of microwave radiation on the technological properties of natural zeolite peets compared to traditional convection method and to determine the optimal drying modes and specific humidity of the material. Material & methods. Granules were prepared by wet granulation technology by using a laboratory granulator NG-12. As the humidifier we used potato starch gel and PVP in an amount of 25% by weight of the dry product. The resulting granules were divided into two equal parts and subjected to drying in a microwave oven (Delfa D20MW of installed capacity (119 W, 280 W, 336 W, 462 W, ​​595 W and 700 W and shelf dryer to a residual moisture level of 0.01 g.w./g.d.m. or less. Determination of the specific humidity of granules was carried out by mass loss on drying. Fractional composition of granules was determined using a standard set of sieves with the diameter of the holes 2.0; 1.0; 0.5 and 0.25 mm. The friability of the granules was determined using friabilator Pharma Test PTF 10E / ER, Germany. To characterize the fluidity of granule Carr`s indicator (IC and coefficient Hausnera (HR. Results & discussion

  20. Microwave Heating Inactivates Shiga Toxin (Stx2) in Reconstituted Fat-Free Milk and Adversely Affects the Nutritional Value of Cell Culture Medium.

    Science.gov (United States)

    Rasooly, Reuven; Hernlem, Bradley; He, Xiaohua; Friedman, Mendel

    2014-04-09

    Microwave exposure is a convenient and widely used method for defrosting, heating, and cooking numerous foods. Microwave cooking is also reported to kill pathogenic microorganisms that often contaminate food. In this study, we tested whether microwaves would inactivate the toxicity of Shiga toxin 2 (Stx2) added to 5% reconstituted fat-free milk administered to monkey kidney Vero cells. Heating of milk spiked with Stx2 in a microwave oven using a 10% duty cycle (cycle period of 30 s) for a total of 165 kJ energy or thermal heating (pasteurization), widely used to kill pathogenic bacteria, did not destroy the biological effect of the toxin in the Vero cells. However, conventional heating of milk to 95 °C for 5 min or at an increased microwave energy of 198 kJ reduced the Stx2 activity. Gel electrophoresis showed that exposure of the protein toxin to high-energy microwaves resulted in the degradation of its original structure. In addition, two independent assays showed that exposure of the cell culture medium to microwave energy of 198 kJ completely destroyed the nutritional value of the culture medium used to grow the Vero cells, possibly by damaging susceptible essential nutrients present in the medium. These observations suggest that microwave heating has the potential to destroy the Shiga toxin in liquid food.

  1. Frequency-tunable microwave field detection in an atomic vapor cell

    Science.gov (United States)

    Horsley, Andrew; Treutlein, Philipp

    2016-05-01

    We use an atomic vapor cell as a frequency tunable microwave field detector operating at frequencies from GHz to tens of GHz. We detect microwave magnetic fields from 2.3 GHz to 26.4 GHz, and measure the amplitude of the σ+ component of an 18 GHz microwave field. Our proof-of-principle demonstration represents a four orders of magnitude extension of the frequency tunable range of atomic magnetometers from their previous dc to several MHz range. When integrated with a high-resolution microwave imaging system [Horsley et al., New J. Phys. 17, 112002 (2015)], this will allow for the complete reconstruction of the vector components of a microwave magnetic field and the relative phase between them. Potential applications include near-field characterisation of microwave circuitry and devices, and medical microwave sensing and imaging.

  2. Handbook on dielectric and thermal properties of microwaveable materials

    CERN Document Server

    Komarov, Vyacheslav V

    2012-01-01

    The application of microwave energy for thermal processing of different materials and substances is a rapidly growing trend in modern science and engineering. In fact, optimal design work involving microwaves is impossible without solid knowledge of the properties of these materials. Here s a practical reference that collects essential data on the dielectric and thermal properties of microwaveable materials, saving you countless hours on projects in a wide range of areas, including microwave design and heating, applied electrodynamics, food science, and medical technology. This unique book provides hard-to-find information on complex dielectric permittivity of media at industrial, scientific, and medical frequencies (430 MHz, 915MHz, 2.45GHz, 5.8 GHz, and 24.125GHz). Written by a leading expert in the field, this authoritative book does an exceptional job at presenting critical data on various materials and explaining what their key characteristics are concerning microwaves.

  3. Design of multiple-layer microwave absorbing structure based on rice husk and carbon nanotubes

    Science.gov (United States)

    Seng, Lee Yeng; Wee, F. H.; Rahim, H. A.; AbdulMalek, MohamedFareq; You, Y. K.; Liyana, Z.; Ezanuddin, A. A. M.

    2017-01-01

    This paper presents a multiple-layered microwave absorber using rice husk and carbon nanotube composite. The dielectric properties of each layer composite were measured and analysed. The different layer of microwave absorber enables to control the microwave absorption performance. The microwave absorption performances are demonstrated through measurements of reflectivity over the frequency range 2-18 GHz. An improvement of microwave absorption <-20 dB is observed with respect to a high lossy composite placed at bottom layer of multiple layers. Reflectivity evaluations indicate that the composites display a great potential application as wideband electromagnetic wave absorbers.

  4. [Determination of organic phosphorus pesticide residues in scallion by gas chromatography coupled with microwave clean-up].

    Science.gov (United States)

    Jiang, Jun; Li, An; Li, Haiyan; Tong, Kexing; Zhou, Lili; Zhou, Huimin; Zhao, Tong

    2007-05-01

    A method for the determination of organic phosphorus pesticide residues is described. It covers 25 residues in scallion including dichlorvos, ethoprophos, phorate, diazinon, disulfoton, dimethoate, pirimiphos-methyl, chlorpyrifos, malathion, fenitrothion, parathion, chlorfenvinphos, ethion, EPN, dyfonate, chlorpyrifos-methyl, parathion-methyl, fenthion, quinalphos, gardona, methidathion, carbophenothion, phosmet, phosalone, and coumaphos. After the scallion samples were heated for 30 s in microwave oven, the residues were extracted with acetonitrile, and then the organic phase was salted out from the matrix. As a result, most of the interfering impurities were abolished in the heating process. In this study, these pesticides were categorized into two groups for analysis. The gas chromatographic analysis was performed on a capillary column (DB-1701, 30 m x 0.25 mm x 0.25 microm) and determined with a flame photometric detector. Linear correlation coefficients of the 25 organic phosphorus pesticides were not lower than 0.991 0 and the linear ranges for most of the compounds were between 0.1 to 5.0 mg/L. The detection limits were between 0.025 and 0.200 mg/L. In recovery study, average recoveries ranged from 85.2% to 119.6% at the fortification levels of 0.05, 0.2 and 0.5 mg/kg and the relative standard deviations were in the range of 2.1% and 14.8%. The method is a simple, rapid and highly efficient one to determine organic phosphorus pesticide residues in scallion.

  5. Variable Power, Short Microwave Pulses Generation using a CW Magnetron

    Directory of Open Access Journals (Sweden)

    CIUPA, R.

    2011-05-01

    Full Text Available Fine control of microwave power radiation in medical and scientific applications is a challenging task. Since a commercial Continuous Wave (CW magnetron is the most inexpensive microwave device available today on the market, it becomes the best candidate for a microwave power generator used in medical diathermy and hyperthermia treatments or high efficiency chemical reactions using microwave reactors as well. This article presents a new method for driving a CW magnetron with short pulses, using a modified commercial Zero Voltage Switching (ZVS inverter, software driven by a custom embedded system. The microwave power generator designed with this method can be programmed for output microwave pulses down to 1% of the magnetron's power and allows microwave low frequency pulse modulation in the range of human brain electrical activity, intended for medical applications. Microwave output power continuous control is also possible with the magnetron running in the oscillating area, using a dual frequency Pulse Width Modulation (PWM, where the low frequency PWM pulse is modulating a higher resonant frequency required by the ZVS inverter's transformer. The method presented allows a continuous control of both power and energy (duty-cycle at the inverter's output.

  6. 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...

  7. Determination of chemical oxygen demand by a flow injection method based on microwave digestion and chromium speciation coupled to inductively coupled plasma optical emission spectrometry.

    Science.gov (United States)

    Almeida, César A; González, Patricia; Mallea, Miguel; Martinez, Luis D; Gil, Raúl A

    2012-08-15

    The present paper evaluates the applicability of a new FIA system for COD determination. The new system, flow injection microwave solid phase extraction by means of activated carbon (FI-MW-SPE), consists of a digestion circuit, placed in a home MW oven, coupled to an ICP-OES spectrophotometer. Doehlert experimental design was used to speed up the optimization of different experimental variables studied for assisted digestion methods. The method provided a high throughput of about 18 samples h(-1). To assess the accuracy of analytical methods linear regression, elliptic joint confidence region (EJCR) was used. A large linear range of 2.78-850 mg O(2) L(-1) with an excellent detection limit of 0.94 mg O(2) L(-1) was obtained. The interference by high chloride concentration was studied, and values below 3000 mg Cl(-) ions L(-1), allowed the estimation of COD load without any masking agents. COD values for various types of wastewater samples were correlated with those obtained by standard manual methods. Moreover, interferences due to matrix nature are absent; since matrix is washed out of the column before Cr (III) is eluted. This method reduces the time, reagent volume, hazardous emission, external contamination, with a good reproducibility and accuracy. Copyright © 2012. Published by Elsevier B.V.

  8. An Experimental Microwave Cavity Alkali Metal Plasma Source

    Science.gov (United States)

    Case, A.; Noonan, W. A.; Skiff, F. N.

    1997-11-01

    A new experimental source for singly ionized alkali metal plasma is presented. This source extends the work of Asmussen et al. al.(J. Asmussen, R. Mallavarpu, J. R. Hamann, H. C. Park Proc. IEEE), 62, 109 (1974)on microwave cavity gas discharges to include Alkali Metals in an effort to provide a simple and inexpensive source of Barium plasma for spectroscopic investigation of plasma phenomena. The source consists of a cylindrical microwave cavity resonant in the TM_112 mode. Barium is vaporized in a specially designed oven and the vapor passed into the cavity through a small opening in one end. The cavity length is adjusted with a moveable plunger so as to maintain the plasma-cavity system in resonance with the 2.45 GHz magnetron feeding power into the cavity. By avoiding plasma resonances, unnecessary heating of the plasma is avoided. The plasma is magnetized (field strength 80-120 Gauss) and the plasma flows along the field lines through a mesh in the plunger and out into the experimental region of the vacuum chamber. This source design holds considerable promise for extension to higher magnetic field strengths.

  9. Vortices at Microwave Frequencies

    Science.gov (United States)

    Silva, Enrico; Pompeo, Nicola; Dobrovolskiy, Oleksandr V.

    2017-11-01

    The behavior of vortices at microwave frequencies is an extremely useful source of information on the microscopic parameters that enter the description of the vortex dynamics. This feature has acquired particular relevance since the discovery of unusual superconductors, such as cuprates. Microwave investigation then extended its field of application to many families of superconductors, including the artificially nanostructured materials. It is then important to understand the basics of the physics of vortices moving at high frequency, as well as to understand what information the experiments can yield (and what they can not). The aim of this brief review is to introduce the readers to some basic aspects of the physics of vortices under a microwave electromagnetic field, and to guide them to an understanding of the experiment, also by means of the illustration of some relevant results.

  10. Tunable Magnetic Resonance in Microwave Spintronics Devices

    Science.gov (United States)

    Chen, Yunpeng; Fan, Xin; Xie, Yunsong; Zhou, Yang; Wang, Tao; Wilson, Jeffrey D.; Simons, Rainee N.; Chui, Sui-Tat; Xiao, John Q.

    2015-01-01

    Magnetic resonance is one of the key properties of magnetic materials for the application of microwave spintronics devices. The conventional method for tuning magnetic resonance is to use an electromagnet, which provides very limited tuning range. Hence, the quest for enhancing the magnetic resonance tuning range without using an electromagnet has attracted tremendous attention. In this paper, we exploit the huge exchange coupling field between magnetic interlayers, which is on the order of 4000 Oe and also the high frequency modes of coupled oscillators to enhance the tuning range. Furthermore, we demonstrate a new scheme to control the magnetic resonance frequency. Moreover, we report a shift in the magnetic resonance frequency as high as 20 GHz in CoFe based tunable microwave spintronics devices, which is 10X higher than conventional methods.

  11. DRYING KINETICS OF OIL PALM FROND WASTE USING SIMPLE BATCH OVEN DRYER

    Directory of Open Access Journals (Sweden)

    Abdul Halim

    2016-06-01

    Full Text Available Drying phenomena of oil palm frond waste as agriculture waste was observed using simple batch oven dryer. The operation temperatures were 50, 80 and 120 °C. The sample of oil palm frond was weighed periodically every 30 minutes. Moisture content, shrinkage phenomena and drying kinetic model were investigated to the difference operation temperature. Experimental result exhibited that temperature influent significantly to the drying rate. The water transport controlled by diffuse mechanism. Shrinkage occurred in radial direction and decreased the size to almost 65% from initial size. In longitudinal direction almost is not change of size.

  12. Air pollution from a large steel factory: polycyclic aromatic hydrocarbon emissions from coke-oven batteries.

    Science.gov (United States)

    Liberti, Lorenzo; Notarnicola, Michele; Primerano, Roberto; Zannetti, Paolo

    2006-03-01

    A systematic investigation of solid and gaseous atmospheric emissions from some coke-oven batteries of one of Europe's largest integrated steel factory (Taranto, Italy) has been carried out. In air monitoring samples, polycyclic aromatic hydrocarbons (PAHs) were consistently detected at concentrations largely exceeding threshold limit values. By means of PAHs speciation profile and benzo(a)pyrene (BaP) equivalent dispersion modeling from diffuse sources, the study indicated that serious health risks exist not only in working areas, but also in a densely populated residential district near the factory.

  13. Robust Design of Terminal ILC with H∞ Mixed Sensitivity Approach for a Thermoforming Oven

    Directory of Open Access Journals (Sweden)

    Guy Gauthier

    2008-01-01

    Full Text Available This paper presents a robust design approach for terminal iterative learning control (TILC. This robust design uses the H∞ mixed-sensitivity technique. An industrial application is described where TILC is used to control the reheat phase of plastic sheets in a thermoforming oven. The TILC adjusts the heater temperature setpoints such that, at the end of the reheat cycle, the surface temperature map of the plastic sheet will converge to the desired one. Simulation results are included to show the effectiveness of the control law.

  14. 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

  15. 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.

  16. Tunable microwave metamaterial absorbers using varactor-loaded split loops

    Science.gov (United States)

    Zhu, Jinfeng; Li, Delong; Yan, Shuang; Cai, Yijun; Huo Liu, Qing; Lin, Timothy

    2015-12-01

    Currently, implementation of active circuit elements within metamaterials is an effective way to make them electrically tunable. We combine varactors with split copper loops in a metamaterial absorber in order to obtain an electrically tunable microwave response. This absorber has a compact planar structure and a simplified back feeding network. Flexible frequency tunability of the microwave reflection in the range of 5-6 GHz is experimentally achieved. The design, simulation, and experimental results are systematically presented. The proposed method is scalable for developing active metamaterial absorbers based on metal loops, and shows a promising potential of active metamaterial absorbers for extensive microwave applications.

  17. Control of pollutants emissions and heat consumption of the CST coke ovens; Controle des emissions de polluants et de la consommation thermique a la cokerie de CST

    Energy Technology Data Exchange (ETDEWEB)

    Clemente, J.M.; Sampaio d' Andrea, C.H.; Da Silva, O.J.; Brandenberger Valente, O.; Lievana, M.; Rabelo de Faria, M. [Arcelor-CST, 92 - Puteaux (France)

    2005-07-15

    To precede the energy and environmental demands, a follow-up of the coke oven batteries was made, to identify the probable causes of pollutants generation and thermal losses. The results of the follow-up of the in/out gases of the coke ovens led to a change of the traditional operational practices, aiming at reducing the air emissions and the energy consumption of the coke ovens. (authors)

  18. Outbreaks of salmonellosis in Minnesota (1998 through 2006) associated with frozen, microwaveable, breaded, stuffed chicken products.

    Science.gov (United States)

    Smith, Kirk E; Medus, Carlota; Meyer, Stephanie D; Boxrud, David J; Leano, Fe; Hedberg, Craig W; Elfering, Kevin; Braymen, Craig; Bender, Jeffrey B; Danila, Richard N

    2008-10-01

    From 1998 through 2006, four outbreaks of salmonellosis associated with raw, frozen, microwaveable, breaded, prebrowned, stuffed chicken products were identified in Minnesota. In 1998, 33 Salmonella Typhimurium cases were associated with a single brand of Chicken Kiev. In 2005, four Salmonella Heidelberg cases were associated with a different brand and variety (Chicken Broccoli and Cheese). From 2005 to 2006, 27 Salmonella Enteritidis cases were associated with multiple varieties of product, predominately of the same brand involved in the 1998 outbreak. In 2006, three Salmonella Typhimurium cases were associated with the same brand of product involved in the 2005 Salmonella Heidelberg outbreak. The outbreak serotype and pulsed-field gel electrophoresis subtype of Salmonella were isolated from product in each outbreak. In these outbreaks, most individuals affected thought that the product was precooked due to its breaded and prebrowned nature, most used a microwave oven, most did not follow package cooking instructions, and none took the internal temperature of the cooked product. Similar to previous salmonellosis outbreaks associated with raw, breaded chicken nuggets or strips in Canada and Australia, inadequate labeling, consumer responses to labeling, and microwave cooking were the key factors in the occurrence of these outbreaks. Modification of labels, verification of cooking instructions by the manufacturer, and notifications to alert the public that these products contain raw poultry, implemented because of the first two outbreaks, did not prevent the other outbreaks. Microwave cooking is not recommended as a preparation method for these types of products, unless they are precooked or irradiated prior to sale.

  19. Validation of microwave digestion method for determination of trace metals in mushrooms.

    Science.gov (United States)

    Kucak, A; Blanusa, M

    1998-12-01

    A microwave digestion method for mushrooms, developed in the study, allows fast preparation of samples and reduces the contamination risk in the process of determining trace metals. Concentrations of six trace elements, Fe, Mn, Cu, Zn, Pb, and Cd were measured in 50 samples of different species of edible mushrooms (fam. Boletaceae) using atomic absorption spectrometry after microwave and dry ashing procedure. The methods were validated through certified Standard Reference Material SRM 1577b (Bovine Liver) which was treated and analysed using the same procedures as for the mushrooms. The samples were either digested with concentrated HNO3 in closed Teflon PFA vessels in a microwave oven, or ashed in quartz crucibles at 450 degrees C. The respective recoveries of Fe, Mn, Zn, Cu, Pb, and Cd obtained by measuring SRM were 112, 107, 104, 115, 111 and 95% after microwave digestion procedure and 86, 101, 109, 111, 98, and 110% after dry ashing procedure. The correlation between concentrations obtained by the two different methods of sample preparation was high for all metals.

  20. A comparative study of infrared and microwave heating for microbial decontamination of paprika powder

    Directory of Open Access Journals (Sweden)

    Lovisa eEliasson

    2015-09-01

    Full Text Available There is currently a need in developing new decontamination technologies for spices due to limitations of existing technologies, mainly regarding their effects on spices’ sensory quality. In the search of new decontamination solutions, it is of interest to compare different technologies, to provide the industry with knowledge for taking decisions concerning appropriate decontamination technologies for spices. The present study compares infrared and microwave decontamination of naturally contaminated paprika powder after adjustment of water activity to 0.88. Infrared respectively microwave heating was applied to quickly heat up paprika powder to 98°C, after which the paprika sample was transferred to a conventional oven set at 98°C to keep the temperature constant during a holding time up to 20 min. In the present experimental set-up microwave treatment at 98°C for 20 min resulted in a reduction of 4.8 log units of the total number of mesophilic bacteria, while the infrared treatment showed a 1 log unit lower reduction for the corresponding temperature and treatment time. Microwave and infrared heating created different temperature profiles and moisture distribution within the paprika sample during the heating up part of the process, which is likely to have influenced the decontamination efficiency. The results of this study are used to discuss the difficulties in comparing two thermal technologies on equal conditions due to differences in their heating mechanisms.

  1. Comparative decomposition kinetics of neutral monosaccharides by microwave and induction heating treatments.

    Science.gov (United States)

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

    2013-06-28

    The stabilities of five neutral monosaccharides (glucose, galactose, mannose, arabinose, and xylose) were kinetically compared after the molecules were submitted to microwave heating (internal heating) and induction heating (external heating) under completely identical thermal histories by employing PID (proportional, integral, and derivative) temperature controlled ovens and homogeneous mixing. By heating in water at 200°C, the rate constants for the decomposition reactions varied from 2.13×10(-4) to 3.87×10(-4)s(-1) for microwave heating; however, the values increased by 1.1- to 1.5-fold for induction heating. Similarly, in a dilute (0.8%) sulfuric acid solution, the decomposition rate constants varied from 0.61×10(-3) to 2.00×10(-3)s(-1) for microwave heating; however, the values increased by 1.5- to 2.2-fold for induction heating. The results show that microwave heating imparts greater stability to neutral monosaccharides than does induction heating. The undesirable decomposition of monosaccharides at the surface boundary of reactor walls may have increased the probability of monosaccharide decomposition during induction heating. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Microwave extraction of bioactive compounds

    Directory of Open Access Journals (Sweden)

    Monika Blekić

    2011-01-01

    Full Text Available Microwave extraction presents novel extraction and treatment method for food processing. In paper, several examples of microwave extraction of bioactive compounds are presented. Also, novel innovative equipment for microwave extraction and hydrodiffusion with gravitation is presented. Advantage of using novel equipment for microwave extraction is shown, and it include, shorter treatment time, less usage or without any solvent use. Novel method is compared to standard extraction methods. Some positive and negative aspects of microwave heating can be observed, and also its influence on development of oxidation in sunflower oil subjected to microwave heating. Also, use of microwaves for the extraction of essential oils is shown. One can also see the advantages of solvent-free microwave extraction of essential oil from aromatic herbs in comparison with the standard extraction, and determination of antioxidant components in rice bran oil extracted by microwave-assisted method. Comparison of microwave and ultrasound extraction, as well as positive and negative aspects of the combination of microwaves and ultrasound is described.

  3. 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 f...

  4. Nonlinear Microwave Optomechanics

    NARCIS (Netherlands)

    Shevchuk, O.

    2017-01-01

    The nonlinearity is essential for creation of non-classical states of the cavity or mechanical resonator such as squeezed or cat states. A microwave cavity can be made nonlinear by, for instance, adding Josephson junctions. The mechanical resonator is inherently nonlinear. The radiation pressure

  5. Microwave plasma for hydrogen production from liquids

    Directory of Open Access Journals (Sweden)

    Czylkowski Dariusz

    2016-06-01

    Full Text Available The hydrogen production by conversion of liquid compounds containing hydrogen was investigated experimentally. The waveguide-supplied metal cylinder-based microwave plasma source (MPS operated at frequency of 915 MHz at atmospheric pressure was used. The decomposition of ethanol, isopropanol and kerosene was performed employing plasma dry reforming process. The liquid was introduced into the plasma in the form of vapour. The amount of vapour ranged from 0.4 to 2.4 kg/h. Carbon dioxide with the flow rate ranged from 1200 to 2700 NL/h was used as a working gas. The absorbed microwave power was up to 6 kW. The effect of absorbed microwave power, liquid composition, liquid flow rate and working gas fl ow rate was analysed. All these parameters have a clear influence on the hydrogen production efficiency, which was described with such parameters as the hydrogen production rate [NL(H2/h] and the energy yield of hydrogen production [NL(H2/kWh]. The best achieved experimental results showed that the hydrogen production rate was up to 1116 NL(H2/h and the energy yield was 223 NL(H2 per kWh of absorbed microwave energy. The results were obtained in the case of isopropanol dry reforming. The presented catalyst-free microwave plasma method can be adapted for hydrogen production not only from ethanol, isopropanol and kerosene, but also from different other liquid compounds containing hydrogen, like gasoline, heavy oils and biofuels.

  6. 3D modelling of coupled mass and heat transfer of a convection-oven roasting process.

    Science.gov (United States)

    Feyissa, Aberham Hailu; Gernaey, Krist V; Adler-Nissen, Jens

    2013-04-01

    A 3D mathematical model of coupled heat and mass transfer describing oven roasting of meat has been developed from first principles. The proposed mechanism for the mass transfer of water is modified and based on a critical literature review of the effect of heat on meat. The model equations are based on a conservation of mass and energy, coupled through Darcy's equations of porous media - the water flow is mainly pressure-driven. The developed model together with theoretical and experimental assessments were used to explain the heat and water transport and the effect of the change in microstructure (permeability, water binding capacity and elastic modulus) that occur during the meat roasting process. The developed coupled partial differential equations were solved by using COMSOL Multiphysics®3.5 and state variables are predicted as functions of both position and time. The proposed mechanism was partially validated by experiments in a convection oven where temperatures were measured online. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Study on compressive strength of self compacting mortar cubes under normal & electric oven curing methods

    Science.gov (United States)

    Prasanna Venkatesh, G. J.; Vivek, S. S.; Dhinakaran, G.

    2017-07-01

    In the majority of civil engineering applications, the basic building blocks were the masonry units. Those masonry units were developed as a monolithic structure by plastering process with the help of binding agents namely mud, lime, cement and their combinations. In recent advancements, the mortar study plays an important role in crack repairs, structural rehabilitation, retrofitting, pointing and plastering operations. The rheology of mortar includes flowable, passing and filling properties which were analogous with the behaviour of self compacting concrete. In self compacting (SC) mortar cubes, the cement was replaced by mineral admixtures namely silica fume (SF) from 5% to 20% (with an increment of 5%), metakaolin (MK) from 10% to 30% (with an increment of 10%) and ground granulated blast furnace slag (GGBS) from 25% to 75% (with an increment of 25%). The ratio between cement and fine aggregate was kept constant as 1: 2 for all normal and self compacting mortar mixes. The accelerated curing namely electric oven curing with the differential temperature of 128°C for the period of 4 hours was adopted. It was found that the compressive strength obtained from the normal and electric oven method of curing was higher for self compacting mortar cubes than normal mortar cube. The cement replacement by 15% SF, 20% MK and 25%GGBS obtained higher strength under both curing conditions.

  8. Impact of operating wood-burning fireplace ovens on indoor air quality.

    Science.gov (United States)

    Salthammer, Tunga; Schripp, Tobias; Wientzek, Sebastian; Wensing, Michael

    2014-05-01

    The use of combustion heat sources like wood-burning fireplaces has regained popularity in the past years due to increasing energy costs. While the outdoor emissions from wood ovens are strictly regulated in Germany, the indoor release of combustion products is rarely considered. Seven wood burning fireplaces were tested in private homes between November 2012 and March 2013. The indoor air quality was monitored before, during and after operation. The following parameters were measured: ultra-fine particles (5.6-560 nm), fine particles (0.3-20 μm), PM2.5, NOx, CO, CO2, formaldehyde, acetaldehyde, volatile organic compounds (VOCs) and benzo[a]pyrene (BaP). Most ovens were significant sources of particulate matter. In some cases, an increase of benzene and BaP concentrations was observed in the indoor air. The results illustrate that wood-burning fireplaces are potential sources of indoor air contaminants, especially ultra-fine particles. Under the aspect of lowering indoor air exchange rates and increasing the use of fuels with a net zero-carbon footprint, indoor combustion sources are an important topic for the future. With regards to consumer safety, product development and inspection should consider indoor air quality in addition to the present fire protection requirements. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Radar range measurements in the atmosphere.

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter

    2013-02-01

    The earths atmosphere affects the velocity of propagation of microwave signals. This imparts a range error to radar range measurements that assume the typical simplistic model for propagation velocity. This range error is a function of atmospheric constituents, such as water vapor, as well as the geometry of the radar data collection, notably altitude and range. Models are presented for calculating atmospheric effects on radar range measurements, and compared against more elaborate atmospheric models.

  10. Proposal and verification numerical simulation for a microwave forward scattering technique at upper hybrid resonance for the measurement of electron gyroscale density fluctuations in the electron cyclotron frequency range in magnetized plasmas

    Science.gov (United States)

    Kawamori, E.; Igami, H.

    2017-11-01

    A diagnostic technique for detecting the wave numbers of electron density fluctuations at electron gyro-scales in an electron cyclotron frequency range is proposed, and the validity of the idea is checked by means of a particle-in-cell (PIC) numerical simulation. The technique is a modified version of the scattering technique invented by Novik et al. [Plasma Phys. Controlled Fusion 36, 357-381 (1994)] and Gusakov et al., [Plasma Phys. Controlled Fusion 41, 899-912 (1999)]. The novel method adopts forward scattering of injected extraordinary probe waves at the upper hybrid resonance layer instead of the backward-scattering adopted by the original method, enabling the measurement of the wave-numbers of the fine scale density fluctuations in the electron-cyclotron frequency band by means of phase measurement of the scattered waves. The verification numerical simulation with the PIC method shows that the technique has a potential to be applicable to the detection of electron gyro-scale fluctuations in laboratory plasmas if the upper-hybrid resonance layer is accessible to the probe wave. The technique is a suitable means to detect electron Bernstein waves excited via linear mode conversion from electromagnetic waves in torus plasma experiments. Through the numerical simulations, some problems that remain to be resolved are revealed, which include the influence of nonlinear processes such as the parametric decay instability of the probe wave in the scattering process, and so on.

  11. Changes in dental enamel oven heated or irradiated with Er,Cr:YSGG laser. Analysis by FTIR

    Science.gov (United States)

    Rabelo, J. S.; Ana, P. A.; Benetti, C.; Valério, M. E. G.; Zezell, D. M.

    2010-04-01

    This study evaluated the change that occurs in dental enamel under action of oven heating or Er,Cr:YSGG laser irradiation aiming to obtain a structure more resistant to demineralization. Enamel powder was obtained from bovine teeth. Samples were subjected to oven heating at temperatures of 200, 400, 600, 800, and 1000°C or during laser irradiation with energy densities of 7.53, 10.95, and 13.74 J/cm2. The infrared thermography was used to measure the surface temperature generated in the solid samples of enamel during lasers irradiation. The samples were analyzed by Fourier transform infrared spectroscopy (FTIR), which shows changes on enamel oven heated or laser irradiated, due to treatments, related to carbonates, adsorbed water and hydroxyl content. These compositional effects were more evident in lased samples. These changes may alter the material properties such as its solubility, and decrese of demineralization that is important for caries prevention.

  12. Microwaves in organic chemistry and organic chemical

    Directory of Open Access Journals (Sweden)

    Mijin Dušan Ž.

    2005-01-01

    Full Text Available The usual way of applying heat to a chemical reaction is the use of a Bunsen burner, an oil or some other type of bath, or an electric heater. In inorganic chemistry, microwave technology has been used since the late 1970s while it has been implemented in organic chemistry since the mid-1980s. Microwave heating has been used in the food industry for almost fifty years. The shorter reaction times and expanded reaction range that is offered by microwave technology are suited to the increased demands in industry. For example, there is a requirement in the pharmaceutical industry for a higher number of a novel chemical entities to be produced, which requires chemists to employ a number of resources to reduce time for the production of compounds. Also, microwaves are used in the food industry, as well as in the pyrolysis of waste materials, sample preparation, the solvent extraction of natural products and the hydrolysis of proteins and peptides.

  13. Very-large-volume sampling of water in gas chromatography using the through oven transfer adsorption desorption (TOTAD) interface for pesticide-residue analysis.

    Science.gov (United States)

    Alario, J; Perez, M; Vazquez, A; Villén, J

    2001-02-01

    The Through Oven Transfer Adsorption Desorption (TOTAD) interface is used to directly introduce large volumes of water (1 mL or more) into a capillary gas chromatograph. The TOTAD interface is a greatly modified programmed temperature vaporizer injector incorporating changes that affect the pneumatics, sample introduction, solvent elimination, and operation mode. The system can easily be automated. The technique is applied to the analysis of pesticide residue in standard solutions and real water samples from the Ebro River (northeastern Spain). The speed of sample introduction was 1 mL/min, and the solvent elimination was almost complete. A nitrogen phosphorous detector is used, and the relative standard deviation varied from 5.7% to 11.7% for the absolute peak areas. The sensitivity achieved by introducing 1 mL of the sample is sufficient for most pesticide-residue analyses in water. The limits of detection ranged from 0.5 to 8.1 ng/L.

  14. Advanced Microwave Circuits and Systems

    DEFF Research Database (Denmark)

    as sufficient gain in a wide frequency range of operation, which is very difficult to achieve. Most circuits demonstrated are not stable across the frequency band, which makes these amplifiers prone to self-oscillations and therefore limit their applicability. The trade-off between noise figure, gain, linearity......This book is based on recent research work conducted by the authors dealing with the design and development of active and passive microwave components, integrated circuits and systems. It is divided into seven parts. In the first part comprising the first two chapters, alternative concepts...... and equations for multiport network analysis and characterization are provided. A thru-only de-embedding technique for accurate on-wafer characterization is introduced. The second part of the book corresponds to the analysis and design of ultra-wideband low-noise amplifiers (LNA). The LNA is the most critical...

  15. Microwave Radiometry in Remote Sensing

    DEFF Research Database (Denmark)

    Gudmandsen, Preben

    1982-01-01

    an international workshop was organized in June 1982 with the object of reviewing the state-o-the-art in applications and techniques and to suggest future development work in data processing and application, systems principles and performance and in component development including the antenna system....... proves useful for measurement of atmospheric parameters. Examples are detection of rain cells and frontal systems, temperature and humidity profiles and content of minor constituents in the atmosphere foremost above the troposphere. The above examples have been demonstrated from radiometer measurements...... from ballon, aircraft and spacecraft and it is expected that the next generation of spacecraft may encompass microwave radiometers in the frequency range from perhaps 1.4 GHz to 700 GHz taking advantage of a number of new developments. With the purpose of identifying the necessary developments...

  16. A fast synthesis for Zintl phase compounds of Na 3SbTe 3, NaSbTe 2 and K 3SbTe 3 by microwave irradiation

    Science.gov (United States)

    Zhou, Gen-Tao; Pol, V. G.; Palchik, Oleg; Kerner, Riki; Sominski, Elena; Koltypin, Yuri; Gedanken, Aharon

    2004-01-01

    The microwave irradiation technique was used to prepare three Zintl phase compounds Na 3SbTe 3, NaSbTe 2 and K 3SbTe 3. The as-prepared products were analyzed and characterized by XRD, EDX and SEM techniques. Higher microwave oven power and shorter irradiation time are required for the synthesis of Na 3SbTe 3, whereas lower oven power and longer irradiation time are needed for NaSbTe 2. Moderate microwave irradiation conditions facilitate the formation of pure K 3SbTe 3. Pure phase of Na 3SbTe 3 are directly obtained by this technique for the first time. Compared with the traditional high-temperature solid-state synthesis, the microwave reaction required a considerable shortened reaction time for the preparation of the three Zintl compounds. The initial driving force for these reactions originates from the interaction of microwave electric field with alkali metals (Na and K) and Sb powders.

  17. Changes occurring in vegetable oils composition due to microwave heating

    Directory of Open Access Journals (Sweden)

    Hassan El-Mallah, M.

    2003-12-01

    Full Text Available The effect of microwave heating on three vegetable oils having different lipid compositions was studied. Sunflower, soybean and peanut oils in comparison with oil admixture of soybean and peanut oil (1:1, w/w, were selected for this study. Each oil was heated for 2, 4, 6, 8, 10, 12, 15 and 18 minutes in microwave oven. Peroxide value, free acidity and colour absorbance (at 420 nm were proportionally increasing with the increase of heating period. Colour absorption threw light on the formation of browning products arising from phospholipids during microwave heating. Total tocopherol contents were determined by preparative thin layer chromatography, whereas the fatty acid compositions and formed epoxy acid were analyzed by capillary gas liquid chromatography. The formed conjugated dienes and trienes were determined by UV spectrophotometry. It was found that the total tocopherols of the microwave heated oils, decreased depending on the type of the predominating tocopherols. Also a relation of peroxide formation, during microwave heating, with changes in total tocopherol composition was discussed. It was found that polyunsaturated fatty acids generally decreased by increasing the heating period. The results obtained from the heated oil admixture helped interpret the results obtained from other heated individual oils.Se estudia el efecto del calentamiento en horno de microondas sobre aceites de diferente composición en ácidos grasos. Aceites de girasol, soja, cacahuete y una mezcla de soja y cacahuete al 50%, se calentaron durante 2, 4, 6, 8 10, 12, 15 y 18 minutos. Los valores de índice de peróxidos, acidez libre y absorbancia a 420 nm fueron proporcionales al tiempo de calentamiento. Otras determinaciones incluyeron el contenido total en tocoferoles mediante cromatografía en capa fina, la composición en ácidos grasos y en epoxiácidos mediante cromatografía gas líquido, y la formación de dienos y trienos conjugados mediante

  18. Cosmos Caudatus as a Potential Source of Polyphenolic Compounds: Optimisation of Oven Drying Conditions and Characterisation of Its Functional Properties

    OpenAIRE

    Chin Ping Tan; Alfi Khatib; Faridah Abas; Ahmed Mediani

    2013-01-01

    The aim of the study was to analyze the influence of oven thermal processing of Cosmos caudatus on the total polyphenolic content (TPC) and antioxidant capacity (DPPH) of two different solvent extracts (80% methanol, and 80% ethanol). Sonication was used to extract bioactive compounds from this herb. The results showed that the optimised conditions for the oven drying method for 80% methanol and 80% ethanol were 44.5 °C for 4 h with an IC50 of 0.045 mg/mL and 43.12 °C for 4.05 h with an IC50 ...

  19. Subwavelength wire array metamaterial microwave cavities

    Science.gov (United States)

    Al-Rubaiee, M.; Alchalaby, A.; Al-Janabi, H.

    2018-01-01

    Wire array metamaterial cavities and waveguides can be achieved by changing the resonance frequency of one or more unit cell surrounding by unit cells don't support the resonance for certain frequency and hence obtain signal confinement only on the defect wires. Changing the resonance frequency of one or more unit cell was done in this work by changing the length of the unit cell. We validate our approach in experiment and simulation with electromagnetic waves in the microwave range.

  20. A simple, time-saving, microwave-assisted periodic acid-Schiff´s staining of glycoproteins on 1D electrophoretic gels.

    Science.gov (United States)

    Moravec, Jiri; Mares, Jan

    2017-12-01

    We introduce an optimized periodic acid-Schiff´s staining of glycoproteins on 1D electrophoretic gels. Thanks to heating in a household microwave oven the protocol of standard periodic acid-Schiff´s staining has been accelerated from 6 h to below 10 min employing standard chemistry. At the same time, we show that the microwave-assisted glycoprotein staining is at least as sensitive as the conventional approach. All glycoproteins stained by the microwave-accelerated procedure were successfully identified using MALDI TOF/TOF mass spectrometry. The ensuing reduction in gel staining time and simplification of the staining protocol should significantly increase laboratory throughput when glycoprotein detection on electrophoretic gels is required in large numbers. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.