bluuebunny/crossref_metadata_2025 huggingface dataset:
A Momentum-conserving Accretion Disk Wind in the Narrow-line Seyfert 1 I Zwicky 1
Authors: Reeves J. N. , Braito V.
Published: October 2019

I Zwicky 1 (hereafter I Zw 1) is the prototype optical narrow-line Seyfert 1 galaxy. It is also a nearby (z = 0.0611), luminous quasi-stellar object (QSO), accreting close to the Eddington limit. XMM-Newton observations of I Zw 1 in 2015 reveal the presence of a broad and blueshifted P Cygni iron K profile, as observed through a blueshifted absorption trough at 9 keV and a broad excess of emission at 7 keV in the X-ray spectra. The profile can be well fitted with a wide-angle accretion disk wind, with an outflow velocity of at least −0.25c. In this respect, I Zw 1 may be analogous to the prototype fast wind detected in the QSO PDS 456, while its overall mass outflow rate is scaled down by a factor of 50, due to its lower black hole mass. The mechanical power of the fast wind in I Zw 1 is constrained to within 5%–15% of Eddington, while its momentum rate is of the order unity. Upper limits placed on the energetics of any molecular outflow, from its CO profile measured by IRAM, appear to rule out the presence of a powerful, large-scale, energy-conserving wind in this active galactic nucleus (AGN). We consider whether I Zw 1 may be similar to a number of other AGNs, such as PDS 456, where the large-scale galactic outflow is much weaker than what is anticipated from models of energy-conserving feedback.
Quasar Properties from the Sloan Digital Sky Survey. II. The Quasars Obtained by the SDSS-IV in the First Two Years
Authors: Chen Zhi-Fu , Yi Shuang-Xi , Pang Ting-Ting , Chen Zhe-Geng , Gui Run-Jin , Wang Zhi-Wen , Mo Xiao-Hua , Yi Ting-Feng
Published: October 2019

This work aims to measure the properties of continuum and emission lines around C iv, Mg ii, Hβ, and Hα for the quasars observed by the extended Baryon Oscillation Spectroscopic Survey (eBOSS) during the first two years. We determine the quasar redshifts based on narrow [O iii] λ5007, broad Mg ii
λ2799, and/or C iv
λ1548 emission lines. The comparisons between the visual inspection redshifts included in DR14Q and the redshifts determined by us suggest that the visual inspection redshifts would be robust. We also infer the virial black hole mass of quasars based on C iv, Mg ii, Hβ, and/or Hα broad emission lines, using empirical relationships reported by previous studies. Systematic differences are remarkable among different line-based mass estimators reported by previous studies. Using the empirical relationship (Equation (1)), we improve the line-based mass estimators by recalibrating new coefficient (a, b), so that different line-based mass estimators are more consistent. We find that (a, b) = (0.96, 0.5), (0.91, 0.5), (0.82, 0.5), and (0.77, 0.5) are the best choices for the Hα-, Hβ-, Mg ii-, and C iv-based mass estimators, respectively. All these above properties are publicly available. We also find that the line and continuum luminosities are tightly correlated with each other. The Balmer lines show a negative Baldwin effect, while the metal lines display a positive Baldwin effect. In addition, we find that tight correlations are indwelled in different line luminosities.
Chromosome spreading of the (TTAGGG)n repeats in the Pipa carvalhoi Miranda-Ribeiro, 1937 (Pipidae, Anura) karyotype
Authors: Zattera Michelle Louise , Lima Luana , Duarte Iraine , Sousa Deborah Yasmin de , Araújo Olívia Gabriela dos Santos , Gazoni Thiago , Mott Tamí , Recco-Pimentel Shirlei Maria , Bruschi Daniel Pacheco
Published: October 2019

Pipidae is a clade of Anura that diverged relatively early from other frogs in the phylogeny of the group. Pipids have a unique combination of morphological features, some of which appear to represent a mix of adaptations to aquatic life and plesiomorphic characters of Anura. The present study describes the karyotype of Pipa carvalhoi Miranda-Ribeiro, 1937, including morphology, heterochromatin distribution, and location of the NOR site. The diploid number of P. carvalhoi is 2n=20, including three metacentric pairs (1, 4, 8), two submetacentric (2 and 7), three subtelocentric (3, 5, 6), and two telocentric pairs (9 and 10). C-banding detected centromeric blocks of heterochromatin in all chromosome pairs and the NOR detected in chromosome pair 9, as confirmed by FISH using the rDNA 28S probe. The telomeric probes indicated the presence of interstitial telomeric sequences (ITSs), primarily in the centromeric region of the chromosomes, frequently associated with heterochromatin, suggesting that these repeats are a significant component of this region. The findings of the present study provide important insights for the understanding of the mechanisms of chromosomal evolution in the genus Pipa, and the diversification of the Pipidae as a whole.
10-Year Results of Small Incision Lenticule Extraction
Authors: Blum Marcus , Lauer Anna S. , Kunert Kathleen S. , Sekundo Walter
Published: October 2019

PURPOSE:

To evaluate the 10-year results of refractive lenticule extraction using the small incision lenticule extraction (SMILE) technique for treatment of myopia and myopic astigmatism.

METHODS:

In 2008–2009, the first 91 eyes were treated using a novel surgical technique (SMILE), in which a refractive lenticule of intrastromal corneal tissue is removed through a small incision, completely eliminating flap cutting. A total of 56 of 91 eyes of the original treatment group volunteered for reexamination 10 years after surgery, including uncorrected and corrected distance visual acuity, objective and manifest refraction, and evaluation of the interface and corneal surface by slit-lamp examination. Late side effects such as corneal scarring, corneal ectasia, persistent dry eye symptoms, or cataract were documented.

RESULTS:

At 10 years postoperatively, there was no significant change from the 6-month results. Spherical equivalent was −0.35 ± 0.66 diopters and therefore close to target refraction. Sixteen of the 56 eyes (29%) had gained one to two Snellen lines. There was no loss of two or more lines in the long term. Regression was −0.35 ± 0.66 diopters over the 10-year period.

CONCLUSIONS:

This 10-year long-term study demonstrates SMILE to be an effective, stable, and safe procedure for the treatment of myopia and myopic astigmatism.

[
J Refract Surg.
2019;35(10):618–623.]
Pediatric Autoimmune Inner Ear Disease: A Rare, But Treatable Condition
Authors: Oz Rotem Semo , Gluth Michael , Tesher Melissa S.
Published: October 2019

Autoimmune inner ear disease (AIED) is a rare, but treatable cause of sudden sensorineural hearing loss in children. Most cases present acutely and involve both ears. The precise mechanism of hearing loss in AIED is not known. Many suspected etiologies have been proposed including infections, vascular abnormalities, and trauma. However, 70% of cases are defined as idiopathic. There are no standardized diagnostic criteria for AIED, and the diagnostic process may be challenging. Positive auto antibodies and response to immunosuppressive therapy support the diagnosis. Treatment may include corticosteroids and steroid-sparing immunosuppressive medications. A high index of suspicion is recommended as the hearing loss may be stabilized or even reversed with early treatment. Long-term medical treatment failures generally have good outcomes with cochlear implantation.

[
Pediatr Ann.
2019;48(10):e391–e394.]
Post-Fire Regeneration of Woody Species in a Colombian Tropical Dry Forest
Authors: Gutiérrez-Rincón Anghy , Parrado-Rosselli Angela
Published: October 2019

In fire-influenced ecosystems, some plant species have the ability to recover, germinate, and to establish after a fire; however, their proportion and dominance varies between sites. The objective of this work was to evaluate natural regeneration following a fire in a tropical dry forest located in the Upper Magdalena River Valley in Colombia. In that way, all seedlings and saplings of woody species were recorded, 1.5 years after a fire, in 75 2x2-m plots installed in burned and unburned forest sites, as well as in forest gaps. Results showed that although abundance was higher in the burned sites, the species richness was lower than in unburned areas. Based on the regeneration response of the species, we identified three groups of plants: 1) fire-stimulated, 2) fire-tolerant, and 3) fire-sensitive species, which means that this tropical dry forest has species with the ability to recover, germinate, and establish after a fire. These three groups of plant species should be considered in restoration programs in light of future and more frequent forest fires due to climate change.
Physiotherapy in geriatrics in the Transvaal
Authors: Beenhakker Johlyne C.
Published: October 2019

No abstract available
Burnout among Moroccan Oncologists: A National Survey
Authors: Benbrahim Zineb , Ibtihal Ahalli , Boujarnija Raihana , Atassi Mariam , Amaadour Lamiaa , Oualla Karima , Arifi Samia , El Fakir Samira , Mellas Nawfel
Published: October 2019

Introduction: Burnout is an unwanted outcome of chronic occupational stressors. Oncology staff is expected to suffer from burnout more than other health-care professionals. The aim of this survey was to determine the prevalence of burnout among Moroccan oncologists and to determine potential causal factors. Methods: We conducted a cross-sectional analytical study using an online self-administered questionnaire to oncologists in Morocco. We used the Maslach Burnout Inventory and additional questions exploring work and lifestyle factors. The questionnaire was sent in January 2018. Results: A total of 100 oncologists answered the questionnaire with predominance of women (75%), young participants (74%), and medical oncologists (60%). Eighty-five percent of the oncologists showed evidence of burnout. The rates of high scores of emotional exhaustion, depersonalization, and low scores of personal accomplishment were, respectively, 57%, 44%, and 56%. In the univariate linear analysis, age younger than 35 years (p = 0.014), being in residency training (p = 0.004), not having extra professional activities (p = 0.009), having an experience less than 10 years (p = 0.02) and estimating vacation time as not adequate (p = 0.05) were all significantly associated with increased burnout scores. In the multivariate analysis, only age <35 years (p = 0.028), being in residency training (p = 0.026), and having an experience less than 10 years (p = 0.01) were independent risk factors of burnout. Conclusion: These findings reveal that burnout in oncologists is higher than those reported internationally. Multidimensional interventions should be implemented to reduce burnout rates among Moroccan oncologists.
Quantum chemistry molecular modeling for radio-frequency and microwave- frequency thermo-upconversion heating of metal oxides of NiO and Fe2O3
Authors: Yanagida Shozo , Matsumura Takeko
Published: October 2019

Under irradiance of 1kW-MW, nickel oxide (Ni(II)O, 25 gr)) can heat up to 1,300°C in 6 min, while ferric oxide (Fe(III)2O3, 25gr) up to 88°C in 30 min. Since Ni(II) and Fe(III) have unpaired electron (spin) of respective 2 and 5, the big difference in the MW heating speed must be explained by thermo-upconversion mechanism as recently verified for quick MW heating of water clusters.1) MW heating power by magnetic loss factor of magnetic metal oxides with unpaired electron, i.e., spin dcould not rationalize such heating-speed and temperature difference. Density functional theory-based molecular modeling(DFT/MM, B3LYP, 6-31G*) of NiO-tetramer of [(NiO)2]2 is successfully carried out with negative heat of formation, giving effective absorption in both FIR and IR regions, which verifies that Ni(II)O should be heated up through thermo-upconversion to the IR region via radio-, MW- and FIR-absorption, i.e., FIR/IR absorption and thermal IR dissipation
MICROWAVE PRETREATMENT OF LIGNOCELLULOSIC BIOMASS TO RELEASE MAXIMUM PHENOLIC ACIDS
Authors: BICHOT Aurélie , DELGENES Jean Philippe , RADOIU Marilena , GARCIA BERNET Diana
Published: October 2019

The objectives fixed by world’s governments concerning energy transition have aroused interest on lignocellulosic biomass utilization for bioenergy and green chemistry applications. However, due to their resistant structure, deconstructive pretreatments are necessary to render possible biological conversions of these lignocellulosic residues. Microwave (MW) treatment has been reported as efficient in many biotechnology fields; biomass pretreatment for biorefinery purposes is another possible application. This work presents the effects of MW pretreatment on underexploited natural agri-food biomass of economic interest: wheat bran, miscanthus stalks and corn stalks. Various parameters were studied including solvent, power density, treatment duration, pressure. Effects were evaluated by a complete biomass characterization before and after treatment, with main focus on phenolic acids release. In the tested conditions and when compared to the high NaOH consumption reference extraction method for phenolic acids, the atmospheric pressure (open vessel) microwave treatment did not allow attaining high acid yields (Fig.1). The most important parameters for improving treatment efficiency were power density and solvent. In order to increase yields, microwave treatments under pressure were carried out to reach higher temperatures while taking care as to not exceed the acid denaturation temperature (150°C) and to avoid the formation of inhibitors. Phenolic acids yields and biomass composition are currently being processed and will be discussed.
EFFECTIVENESS OF A MICROWAVE FLUIDISED BED DRYER IN ERADICATION OF SEED-BORNE BOTRYTIS GREY MOLD OF LENTILS
Authors: Taheri Saeedeh , Brodie Graham Ian , Gupta Dorin
Published: October 2019

Lentil is one of the important pulse crops in the world with a high proportion of easily digestible protein. However, there are several pests and pathogens which cause losses during crop growth, harvesting and post-harvest storage. Microwave processing has shown great potential to eradicate pests and pathogens from grains; however, there is still concerns about its heat uniformity, which is of crucial importance in pest and pathogen control. Fluidization using forced hot air is one of the potential solutions for having uniform temperature during microwave processing. In this study, a single mode microwave cavity, with a 2.45 GHz microwave source, was modified to have a microwave fluidized bed and used to evaluate its potential to eliminate the Botrytis grey mold (BGM) pathogen, which is one of the important seed-borne pathogens of lentil crops in Australia. Air speed was maintained to be constant during the experiment and was just enough to fluidize 100g of red lentils in the sample holder. Two wet based (w.b.) seed moisture contents (m.c.) of 10.5% and 18.5% were prepared and the process parameters were selected as: air temperature at 50 and 60°C; microwave power at 0, 300, 400 W for 18.5% m.c. and 0, 400, 500 W for 10.5% m.c.; and exposure times of 5 and 10 min. These parameters were chosen to reach the final temperature of below 70°C. The effect of process parameters on seed moisture loss, seed germination, electrical conductivity of seed soaking water and percentage of infected seeds (IS%) were analyzed using general factorial regression and analysis of variance. The results showed that the most effective factors on moisture loss, after seed moisture content, was exposure time, followed by microwave power and air temperature. While final bed temperature was affected mostly by air temperature, and then by microwave power. Furthermore, based on general full factorial regression and pareto chart of standardized effects, moisture content had by far the most influence on the reduction of IS%. Seed pathogen inoculum reduction, without significant seed viability loss, was obtained by applying microwave power of 300W and set air temperature of 60°C (actual inlet air temperature of 57±1°C) on seeds with m.c. of 18.5% for 10 min. This gave a 27% reduction in IS% (from 82% to 55%).
A new concept to improve microwave heating uniformity through data-driven process modelling
Authors: Li Yingguang , Zhou Jing , Li Di
Published: October 2019

For a long time, the heating pattern of the workpiece within a multimode microwave oven was considered to be highly sophisticated. As a consequence, the uneven microwave heating problem can only be partly alleviated by a random movement between the electromagnetic field and the workpiece. In this paper, we reported that the heating pattern has a specific correspondence with microwave system settings. The influence factor of the heating pattern and the corresponding mechanism were systematically studied by both theoretical analysis and experimental investigations. On this basis, a data-driven process model was established to learn the material’s dynamic temperature behaviors under different microwave system settings, and a new concept to improve the microwave heating uniformity by temperature monitoring and active compensation was proposed. The effectiveness of the method was demonstrated by a polymer composite microwave processing case study.
MILLIMETER WAVE ABSORPTION IN HYDROXYAPATITE AND 3YSZ CERAMICS IN WIDE TEMPERATURE RANGE
Authors: Eremeev Anatoly , Egorov Sergei , Kholoptsev Vladislav
Published: October 2019

In the field of ceramic-based materials processing the last three decades has been marked by significant academic and industry interest in Additive Manufacturing (AM) technology due to its capability to produce ceramic parts with complex geometry and customizable materials properties. Conceptually, AM technology is a layer-by-layer fabrication of three dimensional physical parts directly from computer-aided design [1]. Solidification of the parts prepared from substances containing ceramic powder may be performed either by conventional heat treatment of a part as whole or by directed energy deposition. Both these strategies can be implemented using gyrotron-based millimeter-wave facilities allowing alternatively both the uniform heating of large-size parts in multi-mode cavities and local heating by focused wave-beams [2]. Hydroxyapatite- and yttria-stabilized zirconia-based ceramics are widely used in biomedical applications due to their high biocompatibility. The knowledge of their microwave absorption variation with temperature and porosity as the materials are densified, is necessary to optimize the scheme of microwave heating. 8 mm diameter disks for the measurements were prepared by uniaxial compacting from commercially available hydroxyapatite (HA) powder and yttria-stabilized zirconia (3YSZ) powder (Tosoh corp.). The measurements were performed at 24 GHz 3 kW gyrotron system. Samples for measurements were placed into the gyrotron system applicator and surrounded with porous alumina based thermal insulation. The design of the applicator and insulation allowed performing optical measurements of both the sample size and temperature distribution over the surface of the sample using a digital monochrome CCD camera. Measurements were made by the calorimetric method, when the microwave power absorbed in the sample is determined basing on the difference of the heating/cooling rates at the moments of intentional abrupt change of the microwave power at different sample temperatures. Absorption coefficient was determined as a division of the absorbed power to the incident microwave power. Special calibration experiments were made for determining microwave power density in the applicator and inside the thermal insulation. The method allows to measure absorption coefficients in situ during the sintering process. Absorption coefficients of HA were obtained in the range of 200 C - 1200 C, and for 3YSZ - in the range of 400 C - 1400 C both in situ during sintering and for as sintered samples. Dependencies of the absorption coefficients on the temperature and porosity are discussed.     References Vaezi, M., et al., Int. J. Adv. Manuf. Technol., 2013, 67, 1721–1759. Bykov, Yu., Eremeev, A., et al., IEEE Trans. Plasma Science, 2004, 32, 67–72.
MICROWAVE RAPID HEATING SYSTEM USING CARBON HEATING TUBE
Authors: SAMESHIMA TOSHIYUKI , Kikuchi T. , Uehara T. , Arima T. , Hasumi M. , Miyazaki T. , Kobayashi G. , Serizawa3 I.
Published: October 2019

We report a microwave heating system with a carbon heating tube (CHT) made by a 4-mm diameter quartz tube filled carbon particles and Ar gas at 1400 Pa. 2.45-GHz microwave at 200 W was introduced to a 300-dimameter metal cavity, in which 60-mm-long CHT was set at the central position. The numerical simulation with a finite element moment method resulted in the standing wave of the electric field caused by three dimensional Fresnel interference effect with low high electric field intensity ranging from from 1 to 6 kV/m because of effective absorption of microwave power by the CHT. The lowest average electrical field intensity of 5 kV/m in the cavity space was given by the electrical conductivity of carbon ranging from 10 to 55 S/m. The CHT with 55 S/m heated to 1200oC by microwave irradiation at 200 W. This heating method was applied to activate 1.0x1015-cm-2 boron and phosphorus implanted regions in n-type crystalline silicon substrate to fabricate pn junction and solar cells. The CHT heating at 1200oC realized decrease in the sheet resistivity to 146 Ω/sq, decrease in the density of defect states to 1.3x1011 and 9.2x1010 cm-2 for boron (p+) and phosphorus (n+) implanted surfaces, and solar cell characteristic with a conversion efficiency of 15% under illumination of air mass 1.5 at 0.1 W/cm2.
CONTINUOUS INDUSTRIAL-SCALE MICROWAVE-ASSISTED EXTRACTION OF HIGH-VALUE INGREDIENTS FROM NATURAL BIOMASS
Authors: Splinter Steven , Radoiu Marilena
Published: October 2019

An innovative technology for the continuous extraction of bioactive compounds from a wide range of biological materials has been developed, scaled up and successfully demonstrated at commercially-relevant scales. The technology, known as MAPTM, or “Microwave-Assisted Process”, robustly transfers from laboratory to continuous, industrial scale operation.  In wide-ranging trials, MAPTM has comprehensively demonstrated its ability to outperform many KPIs of conventional extraction processes, while offering biomass throughput, product consistency and low operational costs not attainable by other emerging technologies. Radient’s proprietary continuous-flow MAPTM extractor, Figure 1, was designed for continuous processing of up to 200 kg/h of biomass material. Verification of the mechanical integrity of the system was confirmed by flow testing of biomass / solvent slurries. Testing and verification of the efficiency of microwave energy transfer to the extractor cavity was completed at various microwave power settings using flowing water at 870 kg/h.  The microwave energy transfer to the system was verified to be >95 % in each case. As an example of performance, continuous flow MAPTM extraction of the antioxidant SDG from flax biomass was performed using 70 % ethanol / water as the solvent at two different conditions: -          75 kg/h flax / 5 L/kg solvent / 15 kW microwave power / extractor residence time 24 min; -          110 kg/h flax / 5 L/kg solvent / 20 kW microwave power / extractor residence time 16 min. The industrial-scale conditions for these runs were determined by extrapolating from optimized conditions previously obtained from batch lab-scale MAPTM experiments. The continuous flow approach eliminates the requirement for having geometric similarity between scales, i.e the equipment shape and dimensions do not have to scale proportionately.
FASTER PLASTICIZERS PRODUCTION BY MICROWAVE IRRADIATION
Authors: Jermolovicius Luiz Alberto , Pouzada Eduardo V. S. , Castro Edmilson R. , Nascimento Renata B. , Senise José T.
Published: October 2019

Plasticizers are esters used to confer plasticity to polymer goods. They are prepared by esterification between a carboxylic acid or anhydride and a heavy alcohol. Esterification is a very slow reaction and its batches may last more than 12 hours of processing [1]. An empirical study of maleic anhydride (MA) esterification with 2-ethyl hexanol (EHO) esterification was done to explore the non-thermal effect of microwaves [2]. In this work a complete 2^3 factorial design and a statistical regression were conducted aiming to stablish empirical complete chemical kinetic equations under microwave heating and under conventional electric heating. The result was a series of six kinetic equations, as shown in Table 1; all parameters are related to -r_MA=k_0∙exp⁡(-E/RT)∙C_MA^nMA∙C_EHO^nEHO, T in Kelvin, and R = 1.9872 cal/mol.K. For a deeper understanding of the results a computer simulation procedure was developed to stimulate this reaction in an isothermal ideal reactor with constant process volume. Interesting numerical results lead to the conclusions that microwave enhanced this slow esterification to a fast reaction as is shown in Figure 1 in the curve labelled ‘microwave heating with 0.012 M of PTSA’.
Microwave Generated Plasma Railway Track Treatment
Authors: Swan Julian , Candy Matt , Radoui Marilena
Published: October 2019

Braking conditions are a fundamental issue for the railway and have been a limiting factor in network capacity & timetabling. This work was focused on taking high power microwave generated plasma out of the laboratory into a railway environment. The Imagination Factory with no experience in microwave generated plasma has partnered with experts in this field to develop a mobile system which delivered 15kW 2.45GHz microwave generated plasma – Fig.1. The plasma was created within a dielectric tube placed in a monomode microwave cavity; the atmospheric plasma sustained in different inert gases (nitrogen, argon) gases as well as mixtures of inert gases with reactive molecules was jetted directly onto the railhead as to change the conditions for the wheel-rail interface. This technology is hoped to be a game changer in enabling predictable & optimized braking on the railway network. Challenges encountered during the demonstration phase will be discussed.
Synergetic effect of microwave plasma and catalysts in CO2 methanation
Authors: Polaert Isabelle , Alrafei Bachar , Delgado-Liriano Jose , Ledoux Alain
Published: October 2019

The reduction of CO2 concentration in our atmosphere consists in a big challenge for researchers, who are trying to explore novel technologies in order to transform CO2 into high added-value products. CO2 conversion into methane using microwave plasma (MWP) manifests as a very promising solution due to the ease of transport of methane and its storage. Microwave plasma represents a source of high-energy electrons, active ions and radicals that enhance or enable chemical reaction. It can be supplied by electricity generated from renewable resources. Then, MWP does not require any electrode to be generated and thus, the cost of those electrodes and of maintenance is reduced compared to glow discharge or DBD plasmas. MWP also can be generated over wide range of pressure (between 10 mbar-1bar). In addition, in the case of MWP, more electrons and active species are produced in comparison with other type of plasma[1–4]. MWP is a very suitable medium for this chemical reaction and leads to an efficient dissociation of CO2. The catalytic reduction of CO2 with H2 using MWP has been investigated in this work and the synergetic effects between the plasma and several catalysts were studied. First, the reaction was carried out without any catalysts and the effect of CO2/H2 ratio, total flow rate and input energy were evaluated. Then, a microwave generated plasma process was coupled with several Nickel catalysts that we prepared and characterized [5] in order to lead the reaction into methane formation. Multiple configurations were studied by changing the position of the catalyst bed. Obtained results were compared with conventional catalytic tests made with the same catalysts. It was found that the conversion of CO2 and energy efficiency increased using plasma assisted catalytic methanation of CO2 in comparison with conventional process. Operating conditions were studied in order to optimize methane production and energy efficiency of Plasma-catalytic process.   References Qin, Y., G. Niu, X. Wang, D. Luo, Y. Duan, J. CO2 Util., 2018, 28, 283–291. De la Fuente, J.F., S.H. Moreno, A.I. Stankiewicz, G.D. Stefanidis, Int J Hydrogen Energy, 2016, 41, 21067–21077. Ashford, B., X. Tu, Curr Opin Green Sustain Chem, 2017, 3, 45–49. Vesel, A., M. Mozetic, A. Drenik, M. Balat-Pichelin, Chem Phys., 2011, 382, 127–131. Alrafei, B., I. Polaert, A. Ledoux, F. Azzolina-Jury, Catal. Today, Available online 12 March 2019, In Press, Accepted Manuscript. https://doi.org/10.1016/j.cattod.2019.03.026
MICROWAVE PYROLYSIS OF BIOMASS IN A ROTATORY KILN REACTOR: DEEP CHARACTERIZATION AND COMPARATIVE ANALYSIS OF PYROLYTIC LIQUIDS PRODUCTS
Authors: Polaert Isabelle , Ubiera Lilivet , Abdelouahed Lokmane , Taouk Bechara
Published: October 2019

The pursuit of sustainable relationship between the production and consumption of energy has accelerated the research into new fuels alternatives, and mainly focused on new technologies for biomass based fuels. Microwave pyrolysis of biomass is a relatively new process which has been long recognized to provide better quality bio-products in shorter reaction time due to the direct sample heating and the particular heating profile resulting from the interaction of biomass with the electric field component of an electromagnetic wave [1,2]. During the course of this research, flax shives were pyrolysed using a rotatory kiln reactor inside a microwave single mode cavity using a range of power between 100 and 200 watts, to reach a temperature range between 450 °C and 650°C. The liquid bio-oil samples recovered in each case were analyzed though gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detection (GC-FID) to identify and quantify the different molecules presents and paying a particular attention to the BTX’s concentration. More than two hundred compounds were identified and grouped into families such as carboxylic acids, alcools, sugars for a deep analysis of the results. The effect of the operating conditions on the proportion of gas, liquid and char produced were studied as well as some properties of the pyrolysis products. In most cases, carboxylic acids were the dominating chemical group present. It was also noticed that the increase of temperature enhanced the carboxylic acids production and diminished the production of other groups, as sugars. Finally, pyrolysis oils were produced in higher quantities by microwaves than in a classical oven and showed a different composition. The examination of the pyrolytic liquid products from different biomass components helped to determine the provenance of each molecule family. On the operational side, the rotatory kiln reactor provided a fast and homogeneous heating profile inside the reactor, desired for fast pyrolysis. The high temperature was maintained without making hot spots during the reaction time. The microwave irradiation setup consisted in a single-mode cavity, a system of plungers, incident and reflected power monitors, an isolator and a 2.45 GHz continuous microwave generator with a power upper limit of 2000 watts. The plunger system was calibrated to maintain a range of reflective wave between 5 and 15%, taking advantage of a minimum of 85 percent of the applied power. In conclusion, the developed microwave pyrolysis process gives a clear way to produce an exploitable bio-oil with enhanced properties.   References Beneroso, D., Monti, T., Kostas, E., Robinson, J., CEJ, 2017.,316, 481- 498. Autunes E., Jacob M., Brodie, G., Schneider, A., JAAP, 2018,129, 93-100.
GROWTH OF NANNOCHLORIS ALGAE IN THE PRESENCE OF MICROWAVES (CONTINUOUS REACTOR)
Authors: Calinescu Ioan , Vintila Alin , Diacon Aurel , Vinatoru Mircea , Galan Ana Maria , Velea Sanda
Published: October 2019

Algae are very effective in capturing the sun's energy, carbon dioxide from the atmosphere, and nutrients to turn them into useful substances (carbohydrates, oils, proteins, etc.). Besides the main metabolites, there are also secondary metabolites, such as carotenoids (astaxanthin, β-carotene, lutein, lycopene, and canthaxanthin [1]). Both major and compounds existing in small amounts in algae are useful. Oils and carbohydrates could provide biofuels, proteins can get products with nutritional value and from carotenoids can be prepared food supplements. Obtaining biofuel from algae has not yet proved to be economically viable [2, 3]. A much higher interest might be getting food supplements from algae. To increase their value as ingredients for food supplements, algal oils should have a higher degree of unsaturation (rich in omega 3) and an increased carotenoid content to be an important additional benefit in over all processing of algae. There are studies that refer to the influence of environmental factors on algae composition [2], but the microwave influence on algae growth, especially algal metabolites composition change is very poor studied. In this paper, besides the experiments for the activation of algal growth in discontinuous reactors [4] additional work was conducted in a continuous photobioreactor. The goal was checking not only the growth of microalgae but also their content in polyunsaturated oil and in carotenoids. By microwave-controlled irradiation of the nutrient and algae flux, which is recirculated through the photobioreactor and through a glass reactor located in a TE-type monomod cavity, the lipid content of the algae increased, but only, the modification of the lipid fraction content was significantly increased in the concentration of polyunsaturated acids with 16 and 18 carbon atoms. As far as carotenoids are concerned, the algae nannochloris has a higher carotenoid content over many known vegetables holding carotene or lycopene (carrots or tomatoes). Besides oil increasing microwave treatment produced a significant increase in carotenoid content of algae. They can be extracted together with omega-3-rich algal oil and are the basis of very valuable dietary supplements.
MICROWAVE-ASSISTED SYNTHESIS AND SPECTROSCOPIC PROPERTIES OF NOVEL PYRIDINE-BASED FLUORESCENT MOLECULAR PROBES
Authors: Fiedor Pawel , Ortyl Joanna , Galek Mariusz
Published: October 2019

Fluorescent molecular probes become interesting analytical tools in determination and labeling of chemical compounds and physical properties such as viscosity and polarity. Currently known fluorescent molecular probes can selectively and regardless of the environment detect only few molecules, and applicability in determination of micro- viscosity and micro-polarity are limited to narrow range and specific condition, therefore design and synthesis of novel molecular probes with extended range of operation are highly needed [1]. Traditional synthesis of 2-amino-4,6-diphenyl-pyridine-3-carbonitrile’s requires two step reaction with long heating time or and toxic solvent. By application of microwave irradiation, reaction time can be firmly shortened with the same or higher efficiency [2]. Derivatives of 2-amino-4,6-diphenyl-pyridine-3-carbonitrile can find application in different fields of science. Depending on the structure of fluorophore, those compounds exhibit high sensitivity to changes in polarity and viscosity of environment, also concentration of specific cations, and pH can be determined by measuring of fluorescence spectrum.
Numerical simulation of the activation process of supersonic gas flows by a microwave discharge.
Authors: Bobrov Maxim , Hrebtov Mikhail , Rebrov Alexey Kuzmich
Published: October 2019

Supersonic gas flows activated by microwave discharge are commonly used to obtain thrust for spacecraft. When using a mixture of hydrocarbons and hydrogen as a working gas, the proposed method generates high-speed plasma streams with a high concentration of radicals, allowing it to be used for efficient deposition of diamond films . To optimize diamond synthesis processes, it is necessary to study the effect of various system parameters (geometrical dimensions, radiation power, pressure and others). This abstract presents a numerical simulation of the formation of high-speed gas flow activated by a microwave discharge. The conjugate problem of hydrodynamics and plasma dynamics was solved in the continuum approximation, taking into account impact ionization and thermal dissociation, due to microwave heating of the gas. The simulations were carried out in an axisymmetric formulation. The region of plasma flow formation was a cylindrical chamber (radius 5 cm, height 7 cm). At this stage, hydrogen was chosen as the working gas. The flow outlet is a hole at the center of the lower boundary with fixed pressure of 2 torr. The gas entered the domain at a constant flow rate of 20 l/min through the openings in side wall along its normal. Such flow rate sustained the mean pressure in the chamber at the level 200 torr. Microwave radiation was injected by a coaxial port located above the plasma chamber. The geometrical dimensions of the resonant chamber were selected in order to form the maximum of the electric field intensity over the gas outflow region (total deposited power 1000W). The distributions of velocity, temperature, and concentrations of all components of the hydrogen plasma were estimated. Optimal characteristics of the system were found to reach a high mole fraction of atomic hydrogen, necessary diamond deposition.
Microwave influenced laminar premixed hydrocarbon flames: Spectroscopic investigations
Authors: Eckart Sven , Behrend Ralph , Krause Hartmut
Published: October 2019

Low laminar burning velocity’s and slow reactions propagation are among a key problem in combustion processes with low calorific gas mixtures. The mixtures have a laminar burning velocity of 10 cm/s to 15 cm/s or even below which is 37% of natural gas. Thermal use of these gases could save considerable amounts of fossil fuel and reduce CO2 emissions. Due to low burning velocities and low enthalpy of combustion, ignition and stable combustion is complex, often preventing utilization of these gases. Microwave-assisted combustion can help to solve these problems. With microwave assistance, these gas mixtures could be burned with a higher burning velocity without preheating or co-firing. Therefore, this effect could be used for flame stabilization processes in industry applications. Microwaves could also change the combustion properties, for example radical formation and flame thickness.   In this paper, we explore a possibility of using microwaves to increase the burning velocity of propane as one component in low calorific gas mixtures and also show higher productions of OH* and CH* radicals with an increase of the input microwave power. Different compositions of low calorific fuels were tested within a range of equivalence ratios from φ= 0.8 to φ= 1.3 for initial temperatures of 298 K and atmospheric conditions and microwave powers from 120 W to 600 W.   For the experiments, a standard WR340 waveguide was modified with a port for burner installation and filter elements allowing for flue gas exhaust and optical access from the side. A 2.45 GHz CW magnetron was used as microwave source, microwave measurements were carried out with a 6-port- reflectometer with integrated three stub tuner. An axisymmetric premixed burner was designed to generate a steady conical laminar premixed flame stabilized on the outlet of a contoured nozzle under atmospheric pressure. The burner was operated with a propane mass flow of 0.2-0.4 nl/min at an equivalence ratio of φ= 0.8 to φ= 1.3. The optical techniques used in the current study are based on the flame contours detection by using the OH* chemiluminescence image technique. For every experimental case, 150 pictures were taken and averaged. Additionally, spectroscopic analysis of the flames was undertaken.   The results suggest that production of OH* radicals in the flame front increases with microwave power. For evaluation, a picture based OH* chemiluminescence and a spectrographic method was used. In addition, a 9.9% increase of the burning velocity was observed in the premixed propane-air mixture for a 66 Watt absorbed microwave power. This effect is attributed to the increased OH* (~310nm) and CH* (~420nm) radical formation, which also reduces the flame thickness. It was found that absorption of microwaves in flames is generally low, but could be improved by a customized applicator design.
TUNGSTEN CARBIDE NANOPOWDER SYNTHESIS UNDER THE EXPOSURE OF 24 GHZ GYROTRON RADIATION ON THE NANOCOMPOSITE OF THE W-C SYSTEM OBTAINED IN A THERMAL PLASMA
Authors: Vodopyanov Alexander , Samokhin Andrey , Aleksev Nikolay , Sinayskiy Mikhail , Sorokin Andrey , Sintsov Sergey
Published: October 2019

Nanoscale tungsten carbide WC powders are of practical interest for the creation of nanostructured hard alloys with enhanced physical and mechanical characteristics, wear-resistant nanostructured coatings, electrocatalysts in fuel cells, metal melt modifiers [1]. An efficient method for producing tungsten carbide nanopowder is a plasma-chemical synthesis of a multi-component powder nanocomposite system W-C in combination with its subsequent heat treatment [2]. Experimental studies have shown the possibility of producing tungsten carbide WC nanopowder by this method. But the transformation of the nanocomposite in the target product is accompanied by an increase in the size of nanoparticles. We assume that this growth is associated with prolonged heating (several hours) in an electric furnace at a temperature of about 1000 ° C. This time is necessary for the complete transformation of the nanocomposite into the target product. The aim of the work was an experimental study of the formation of tungsten carbide nanopowder WC when processing a multi-component powder nanocomposite system W-C in an electromagnetic field with a frequency of 24 GHz. A multipurpose gyrotron system with a nominal power of 7 kW with at a frequency of 24 GHz was used for the experiments. The microwave application system described in [3]. The powders were treated in an argon flow. The experiments were carried varying exposure time and microwave power. The samples of nanopowders obtained in the experiments were analyzed using the following methods: XRD, TEM, SEM, BET, LDA, CEA. It was established that microwave radiation with a frequency of 24 GHz allows heating samples of powders to a temperature of 1100-1200 C almost immediately (after 1-2 s) after switching on. The tungsten carbide WC is formed in a few minutes under the exposure to microwave radiation of the original W-C nanocomposite system. There is only a slight increase in the average particle size from 20 to 30 nm. The investigations showed that the synthesis of tungsten carbide WC under the microwave heating as compared to conventional heating in an electric furnace may be carried out for significantly less time while maintaining the particles in the nanometer range.The work was carried out within the framework of the Program #14 "Physical chemistry of adsorption phenomena and actinide nanoparticles" of the Presidium of the Russian Academy of Sciences.References Z. Zak Fang, Xu Wang, et al. Int. Journal of Refractory Metals & Hard Materials, 2009, 27, 288–299.Samokhin A., Alekseev N., et al. Plasma Chem. Plasma Proc., 2013, 33, 605–616.Samokhin A., Alekseev N., et al. J. Nanotechnol. Eng. Med., 2015, 6, 011008.
LOW-COST MEASUREMENT SYSTEM AND FILTER FOR REDUCTION OF EMC INTERFERENCES IN RADIO-FREQUENCY APPLICATIONS
Authors: Roland Ulf , Sallier René , Nietner Lutz , Trommler Ulf , Kraus Markus , Holzer Frank , Hoyer Christian , Schlayer Detlef
Published: October 2019

For drying building structures [1], dielectric heating using RF energy (in this case 13.56 MHz) is an efficient and fast alternative to conventional heating methods based on heat transfer from the surface to the interior of the masonry. Another innovative application of volumetric RF heating is the chemical-free pest control in wood-based materials [2]. For such applications where the RF systems often are not completely shielded, the propagation or coupling of the electromagnetic wave into wires that are placed inside the field cannot be neglected which represents a certain risk. Depending on the different electromagnetic coupling mechanisms, several interference signals can be generated. In order to protect electrical equipment in the surrounding, these interferences have to be significantly reduced by electrical filters. For this purpose, initially a cost-effective (at least in comparison to standard RF measurement systems) and more robust measuring concept was developed. With the help of this system, the common mode (I_CM) interference could be identified as the dominant part and the differential mode (I_DM) interference as a minor disturbance. Based on the experimental evaluation, a cost-effective filter for the respective disturbance was constructed and successfully tested.
High Efficiency Microwave Flow Chemistry Towards Synthesis of Functional Materials and Pharmaceutical Cores
Authors: Barham Joshua Philip , Norikane Yasuo , Egami Hiromichi , Hamashima Yoshitaka
Published: October 2019

Microwave (MW) heating benefits organic synthesis by affording higher product yields in shorter time periods than conventional heating, yet it suffers from poor scalability and is limited to polar solvents in typical batch mode reactors. Herein, we report a microwave flow reactor using a solid-state semiconductor MW generator. The tunable, single-mode MW heating allows high efficiency, scalable organic synthesis, rapid reaction optimization and is applicable to non-polar solvents (o-Xylene and CPME can be rapidly heated to ca. 260 oC). Auto-frequency tuning compensates for changes in the microwave absorption properties (permittivity, epsilon) with increasing temperature, affording excellent temperature and process control. This technology unlocked unprecedented g/h productivity of C60/fullerene-indene monoadduct (IC60MA) and facilitated a novel, transition metal-free amide-styrene coupling reaction for synthesis of amide-containing pharmaceutical cores in up to 65 g/h (Figure 1). An ortho-Claisen rearrangement reaction was rapidly optimised.