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Sample records for ir thermogravimetric analysis

  1. Thermogravimetric Analysis Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — At NETL’s Thermogravimetric Analysis Laboratory in Morgantown, WV, researchers study how chemical looping combustion (CLC) can be applied to fossil energy systems....

  2. Kinetic parameters from thermogravimetric analysis

    Science.gov (United States)

    Kiefer, Richard L.

    1993-01-01

    High performance polymeric materials are finding increased use in aerospace applications. Proposed high speed aircraft will require materials to withstand high temperatures in an oxidative atmosphere for long periods of time. It is essential that accurate estimates be made of the performance of these materials at the given conditions of temperature and time. Temperatures of 350 F (177 C) and times of 60,000 to 100,000 hours are anticipated. In order to survey a large number of high performance polymeric materials on a reasonable time scale, some form of accelerated testing must be performed. A knowledge of the rate of a process can be used to predict the lifetime of that process. Thermogravimetric analysis (TGA) has frequently been used to determine kinetic information for degradation reactions in polymeric materials. Flynn and Wall studied a number of methods for using TGA experiments to determine kinetic information in polymer reactions. Kinetic parameters, such as the apparent activation energy and the frequency factor, can be determined in such experiments. Recently, researchers at the McDonnell Douglas Research Laboratory suggested that a graph of the logarithm of the frequency factor against the apparent activation energy can be used to predict long-term thermo-oxidative stability for polymeric materials. Such a graph has been called a kinetic map. In this study, thermogravimetric analyses were performed in air to study the thermo-oxidative degradation of several high performance polymers and to plot their kinetic parameters on a kinetic map.

  3. Thermogravimetric analysis of forest understory grasses

    Science.gov (United States)

    Thomas Elder; John S. Kush; Sharon M. Hermann

    2011-01-01

    Forest understory grasses are of significance in the initiation, establishment and maintenance of fire, whether used as a management tool or when occurring as wildfire. The fundamental thermal properties of such grasses are critical to their behavior in fire situations and have been investigated in the current work by the application of thermogravimetric analysis (TGA...

  4. Thermogravimetric analysis of biowastes during combustion

    International Nuclear Information System (INIS)

    Otero, M.; Sanchez, M.E.; Gomez, X.; Moran, A.

    2010-01-01

    The combustion of sewage sludge (SS), animal manure (AM) and the organic fraction of municipal solid waste (OFMSW) was assessed and compared with that of a semianthracite coal (SC) and of a PET waste by thermogravimetric (TG) analysis. Differences were found in the TG curves obtained for the combustion of these materials accordingly to their respective proximate analysis. Non-isothermal thermogravimetric data were used to assess the kinetics of the combustion of these biowastes. The present paper reports on the application of the Vyazovkin model-free isoconversional method for the evaluation of the activation energy necessary for the combustion of these biowastes. The activation energy related to SS combustion (129.1 kJ/mol) was similar to that corresponding to AM (132.5 kJ/mol) while the OFMSW showed a higher value (159.3 kJ/mol). These values are quite higher than the one determined in the same way for the combustion of SC (49.2 kJ/mol) but lower than that for the combustion of a PET waste (165.6 kJ/mol).

  5. Thermogravimetric analysis of fuel film evaporation

    Institute of Scientific and Technical Information of China (English)

    HU Zongjie; LI Liguang; YU Shui

    2006-01-01

    Thermogravimetric analysis (TGA) was compared with the petrochemical distillation measurement method to better understand the characteristics of fuel film evaporation at different wall tem- peratures. The film evaporation characteristics of 90# gasoline, 93# gasoline and 0# diesel with different initial thicknesses were investigated at different environmental fluxes and heating rates. The influences of heating rate, film thickness and environmental flux on fuel film evaporation for these fuels were found. The results showed that the environmental conditions in TGA were similar to those for fuel films in the internal combustion engines, so data from TGA were suitable for the analysis of fuel film evaporation. TGA could simulate the key influencing factors for fuel film evaporation and could investigate the basic quantificational effect of heating rate and film thickness. To get a rapid and sufficient fuel film evaporation, sufficiently high wall temperature is necessary. Evaporation time decreases at a high heating rate and thin film thickness, and intense gas flow is important to promoting fuel film evaporation. Data from TGA at a heating rate of 100℃/min are fit to analyze the diesel film evaporation during cold-start and warming-up. Due to the tense molecular interactions, the evaporation sequence could not be strictly divided according to the boiling points of each component for multicomponent dissolved mixture during the quick evaporation process, and the heavier components could vaporize before reaching their boiling points. The 0# diesel film would fully evaporate when the wall temperature is beyond 250℃.

  6. Thermogravimetric analysis and fast pyrolysis of Milkweed.

    Science.gov (United States)

    Kim, Seung-Soo; Agblevor, Foster A

    2014-10-01

    Pyrolysis of Milkweed was carried out in a thermogravimetric analyzer and a bubbling fluidized bed reactor. Total liquid yield of Milkweed pyrolysis was between 40.74% and 44.19 wt% between 425 °C and 550 °C. The gas yield increased from 27.90 wt% to 33.33 wt% with increasing reaction temperature. The higher heating values (HHV) of the Milkweed bio-oil were relatively high (30.33-32.87 MJ/kg) and varied with reaction temperature, feeding rate and fluidization velocity. The selectivity for CO2 was highest within non-condensable gases, and the molar ratio of CO2/CO was about 3 at the different reaction conditions. The (13)C NMR analysis, of the bio-oil showed that the relative concentration carboxylic group and its derivatives was higher at 425 °C than 475 °C, which resulted in slightly higher oxygen content in bio-oil. The pH of aqueous phase obtained at 475 °C was 7.37 which is the highest reported for any lignocellulosic biomass pyrolysis oils. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Isothermal thermogravimetric data acquisition analysis system

    Science.gov (United States)

    Cooper, Kenneth, Jr.

    1991-01-01

    The description of an Isothermal Thermogravimetric Analysis (TGA) Data Acquisition System is presented. The system consists of software and hardware to perform a wide variety of TGA experiments. The software is written in ANSI C using Borland's Turbo C++. The hardware consists of a 486/25 MHz machine with a Capital Equipment Corp. IEEE488 interface card. The interface is to a Hewlett Packard 3497A data acquisition system using two analog input cards and a digital actuator card. The system provides for 16 TGA rigs with weight and temperature measurements from each rig. Data collection is conducted in three phases. Acquisition is done at a rapid rate during initial startup, at a slower rate during extended data collection periods, and finally at a fast rate during shutdown. Parameters controlling the rate and duration of each phase are user programmable. Furnace control (raising and lowering) is also programmable. Provision is made for automatic restart in the event of power failure or other abnormal terminations. Initial trial runs were conducted to show system stability.

  8. Study on high-silicon boron-containing zeolite by thermogravimetric and IR-spectroscopy techniques

    International Nuclear Information System (INIS)

    Chukin, G.D.; Nefedov, B.K.; Surin, S.A.; Polinina, E.V.; Khusid, B.L.; Sidel'kovskaya, V.G.

    1985-01-01

    The structure identity of initial Na-forms of boron-containing and aluminosilicate high-silicon zeolites is established by thermogravimetric and IR-spectroscopy methods. The presence of boron in Na-forms of high-silicon zeolites is shown to lead to reduction of structure thermal stability. It is noted that thermal stability of the H-form of both high-silicon boron-containing and boron-free zeolites is practically equal and considerably higher than that of Na-forms

  9. Thermogravimetric analysis and dissociation pressure of caesium trihalides

    International Nuclear Information System (INIS)

    Harris, G.S.; McKechnie, J.S.

    1982-01-01

    We have carried out a thermogravimetric study of caesium trihalides to obtain, from the procedural decomposition temperatures, an order of apparent thermal stability which could be compared with the order of thermodynamic stability obtained from vapour pressure measurements. Thermogravimetric analysis could also prove to be a useful method for rapid analysis of metal polyhalides. The thermograms indicated a one-step decomposition for each compound; the procedural decomposition temperatures and percentage weight losses obtained are given. Dissociation pressures were measured and values of equilibrium constant and enthalpy of dissociation were calculated. The results are given. The 'stability' order obtained is discussed. (U.K.)

  10. Thermogravimetric-quadrupole mass-spectrometric analysis of geochemical samples.

    Science.gov (United States)

    Gibson, E. K., Jr.; Johnson, S. M.

    1972-01-01

    Thermogravimetric-quadrupole mass-spectrometric-analysis techniques can be used to study a wide variety of problems involving decomposition processes and identification of released volatile components. A recording vacuum thermoanalyzer has been coupled with a quadrupole mass spectrometer. The rapid scan capabilities of the quadrupole mass spectrometer are used to identify the gaseous components released. The capability of the thermogravimetric-quadrupole mass spectrometer to provide analytical data for identification of the released volatile components, for determination of their sequence of release and for correlation of thermal-decomposition studies is illustrated by an analysis of the Orgueil carbonaceous chondrite.

  11. A simple, sensitive graphical method of treating thermogravimetric analysis data

    Science.gov (United States)

    Abraham Broido

    1969-01-01

    Thermogravimetric Analysis (TGA) is finding increasing utility in investigations of the pyrolysis and combustion behavior of materuals. Although a theoretical treatment of the TGA behavior of an idealized reaction is relatively straight-forward, major complications can be introduced when the reactions are complex, e.g., in the pyrolysis of cellulose, and when...

  12. Thermogravimetric analysis of reactor-neutrons-irradiated LEXAN polycarbonate film

    International Nuclear Information System (INIS)

    Kalsi, P.C.

    2000-01-01

    The effects of reactor-neutrons irradiation on the thermogravimetric (TG) analysis of LEXAN polycarbonate film in air were studied. Irradiation enhances the degradation rate and the effect increases further with increasing neutron fluence. The kinetics of the different steps of degradation were also evaluated from the TG curves. The activation energy values calculated for all the degradation stages decrease on irradiation. (author)

  13. Heater-Integrated Cantilevers for Nano-Samples Thermogravimetric Analysis

    OpenAIRE

    Toffoli, Valeria; Carrato, Sergio; Lee, Dongkyu; Jeon, Sangmin; Lazzarino, Marco

    2013-01-01

    The design and characteristics of a micro-system for thermogravimetric analysis (TGA) in which heater, temperature sensor and mass sensor are integrated into a single device are presented. The system consists of a suspended cantilever that incorporates a microfabricated resistor, used as both heater and thermometer. A three-dimensional finite element analysis was used to define the structure parameters. TGA sensors were fabricated by standard microlithographic techniques and tested using mill...

  14. Curie temperature determination via thermogravimetric and continuous wavelet transformation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Hasier, John; Nash, Philip [Thermal Processing Technology Center, IIT, Chicago, IL (United States); Riolo, Maria Annichia [University of Michigan, Center for the Study of Complex Systems, Ann Arbor, MI (United States)

    2017-12-15

    A cost effective method for conversion of a vertical tube thermogravimetric analysis system into a magnetic balance capable of measuring Curie Temperatures is presented. Reference and preliminary experimental data generated using this system is analyzed via a general-purpose wavelet based Curie point edge detection technique allowing for enhanced speed, ease and repeatability of magnetic balance data analysis. The Curie temperatures for a number of Heusler compounds are reported. (orig.)

  15. Thermogravimetric Analysis of Single-Wall Carbon Nanotubes

    Science.gov (United States)

    Arepalli, Sivram; Nikolaev, Pavel; Gorelik, Olga

    2010-01-01

    An improved protocol for thermogravimetric analysis (TGA) of samples of single-wall carbon nanotube (SWCNT) material has been developed to increase the degree of consistency among results so that meaningful comparisons can be made among different samples. This improved TGA protocol is suitable for incorporation into the protocol for characterization of carbon nanotube material. In most cases, TGA of carbon nanotube materials is performed in gas mixtures that contain oxygen at various concentrations. The improved protocol is summarized.

  16. Thermogravimetric analysis of the gasification of microalgae Chlorella vulgaris.

    Science.gov (United States)

    Figueira, Camila Emilia; Moreira, Paulo Firmino; Giudici, Reinaldo

    2015-12-01

    The gasification of microalgae Chlorella vulgaris under an atmosphere of argon and water vapor was investigated by thermogravimetric analysis. The data were interpreted by using conventional isoconversional methods and also by the independent parallel reaction (IPR) model, in which the degradation is considered to happen individually to each pseudo-component of biomass (lipid, carbohydrate and protein). The IPR model allows obtaining the kinetic parameters of the degradation reaction of each component. Three main stages were observed during the gasification process and the differential thermogravimetric curve was satisfactorily fitted by the IPR model considering three pseudocomponents. The comparison of the activation energy values obtained by the methods and those found in the literature for other microalgae was satisfactory. Quantification of reaction products was performed using online gas chromatography. The major products detected were H2, CO and CH4, indicating the potential for producing fuel gas and syngas from microalgae. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Characterization and thermogravimetric analysis of lanthanide hexafluoroacetylacetone chelates.

    Science.gov (United States)

    Shahbazi, Shayan; Stratz, S Adam; Auxier, John D; Hanson, Daniel E; Marsh, Matthew L; Hall, Howard L

    2017-01-01

    This work reports the thermodynamic characterizations of organometallic species as a vehicle for the rapid separation of volatile nuclear fission products via gas chromatography due to differences in adsorption enthalpy. Because adsorption and sublimation thermodynamics are linearly correlated, there is considerable motivation to determine sublimation enthalpies. A method of isothermal thermogravimetric analysis, TGA-MS and melting point analysis are employed on thirteen lanthanide 1,1,1,5,5,5-hexafluoroacetylacetone complexes to determine sublimation enthalpies. An empirical correlation is used to estimate adsorption enthalpies of lanthanide complexes on a quartz column from the sublimation data. Additionally, four chelates are characterized by SC-XRD, elemental analysis, FTIR and NMR.

  18. Heater-Integrated Cantilevers for Nano-Samples Thermogravimetric Analysis

    Directory of Open Access Journals (Sweden)

    Valeria Toffoli

    2013-12-01

    Full Text Available The design and characteristics of a micro-system for thermogravimetric analysis (TGA in which heater, temperature sensor and mass sensor are integrated into a single device are presented. The system consists of a suspended cantilever that incorporates a microfabricated resistor, used as both heater and thermometer. A three-dimensional finite element analysis was used to define the structure parameters. TGA sensors were fabricated by standard microlithographic techniques and tested using milli-Q water and polyurethane microcapsule. The results demonstrated that our approach provides a faster and more sensitive TGA with respect to commercial systems.

  19. Heater-Integrated Cantilevers for Nano-Samples Thermogravimetric Analysis

    Science.gov (United States)

    Toffoli, Valeria; Carrato, Sergio; Lee, Dongkyu; Jeon, Sangmin; Lazzarino, Marco

    2013-01-01

    The design and characteristics of a micro-system for thermogravimetric analysis (TGA) in which heater, temperature sensor and mass sensor are integrated into a single device are presented. The system consists of a suspended cantilever that incorporates a microfabricated resistor, used as both heater and thermometer. A three-dimensional finite element analysis was used to define the structure parameters. TGA sensors were fabricated by standard microlithographic techniques and tested using milli-Q water and polyurethane microcapsule. The results demonstrated that our approach provides a faster and more sensitive TGA with respect to commercial systems.

  20. Quantitation of Surface Coating on Nanoparticles Using Thermogravimetric Analysis.

    Science.gov (United States)

    Dongargaonkar, Alpana A; Clogston, Jeffrey D

    2018-01-01

    Nanoparticles are critical components in nanomedicine and nanotherapeutic applications. Some nanoparticles, such as metallic nanoparticles, consist of a surface coating or surface modification to aid in its dispersion and stability. This surface coating may affect the behavior of nanoparticles in a biological environment, thus it is important to measure. Thermogravimetric analysis (TGA) can be used to determine the amount of coating on the surface of the nanoparticle. TGA experiments run under inert atmosphere can also be used to determine residual metal content present in the sample. In this chapter, the TGA technique and experimental method are described.

  1. Biomass Thermogravimetric Analysis: Uncertainty Determination Methodology and Sampling Maps Generation

    Science.gov (United States)

    Pazó, Jose A.; Granada, Enrique; Saavedra, Ángeles; Eguía, Pablo; Collazo, Joaquín

    2010-01-01

    The objective of this study was to develop a methodology for the determination of the maximum sampling error and confidence intervals of thermal properties obtained from thermogravimetric analysis (TG), including moisture, volatile matter, fixed carbon and ash content. The sampling procedure of the TG analysis was of particular interest and was conducted with care. The results of the present study were compared to those of a prompt analysis, and a correlation between the mean values and maximum sampling errors of the methods were not observed. In general, low and acceptable levels of uncertainty and error were obtained, demonstrating that the properties evaluated by TG analysis were representative of the overall fuel composition. The accurate determination of the thermal properties of biomass with precise confidence intervals is of particular interest in energetic biomass applications. PMID:20717532

  2. Study and Thermogravimetric analysis of Poly N-4 Aminostyrol

    International Nuclear Information System (INIS)

    Meghezzi, A.; Lakhdar, Y.; Saidi, M.; Dadamoussa, B.

    2006-01-01

    The polyaminostyrol samples (PAS) and their copolymers with the styrol differing in position and quantity of amino-group, were obtained by polymerization of monomers on cyclogexan solution. The observed thermal effects were analyzed by the differential thermal analysis combined with a thermogravimetric analysis. It was found that the introduction of amino-groups into the polystyrols increased the temperature of total degradation of polymer from 150 till 260C. The increase in thermostability may be explained by the cohesion of macromolecules with the participation of amino-groups, which results in ammonium evolution, as well as in the decrease of valence area band of -NH2 grouping the region 3370-34440 cm. It was showed that the degree of cohesion formation and thermolysis rate depended on amino-group and their position into the cycle of benzene. (author)

  3. Thermogravimetric analysis of the beryllium/steam reaction

    Energy Technology Data Exchange (ETDEWEB)

    Druyts, Frank E-mail: fdruyts@sckcen.be; Iseghem, Pierre van

    2000-11-01

    In view of the safety assessment of new fusion reactor designs, kinetic data are needed on the beryllium/steam reaction. Therefore, thermogravimetric analysis was used to determine the reactivity of beryllium in steam as a function of temperature, irradiation history and porosity of the samples. To this purpose, reference unirradiated S-200 VHP beryllium samples were compared with specimens irradiated in the BR2 reactor up to fast neutron fluences (E>1 MeV) of respectively 1.6x10{sup 21} n cm{sup -2} (resulting in a helium content of 300 appm He and a theoretical density of 99.9%) and 4x10{sup 22} n cm{sup -2} (21000 appm He, 97.2% theoretical density). Kinetics were parabolic for all tested beryllium types at 600 deg. C. At 700 deg. C, kinetics were parabolic for the unirradiated and irradiated 99.9% dense beryllium, and accelerating/linear for the irradiated 97.2% material. At 800 deg. C, all samples showed accelerating/linear behaviour. There was no influence of porosity on the reaction rate of beryllium in steam within the limited investigated density range, except at 700 deg. C, where the measured reaction rate for the irradiated 97.2% dense samples is an order of magnitude higher than for the irradiated 99.9% dense specimens.

  4. Pyrolysis and combustion kinetics of lycopodium particles in thermogravimetric analysis

    Institute of Scientific and Technical Information of China (English)

    Seyed Alireza Mostafavi; Sadjad Salavati; Hossein Beidaghy Dizaji; Mehdi Bidabadi

    2015-01-01

    Biomass is a kind of renewable energy which is used increasingly in different types of combustion systems or in the production of fuels like bio-oil. Lycopodium is a cellulosic particle, with good combustion properties, of which microscopic images show that these particles have spherical shapes with identical diameters of 31 μm. The measured density of these particles is 1.0779 g/cm2. Lycopodium particles contain 64.06% carbon, 25.56% oxygen, 8.55% hydrogen and 1.83% nitrogen, and no sulfur. Thermogravimetric analysis in the nitrogen environment indicates that the maximum of particle mass reduction occurs in the temperature range of 250−550 °C where the maximum mass reduction in the DTG diagrams also occurs in. In the oxygen environment, an additional peak can also be observed in the temperature range of 500−600 °C, which points to solid phase combustion and ignition temperature of lycopodium particles. The kinetics of reactions is determined by curve fitting and minimization of error.

  5. Thermal decomposition kinetics of sorghum straw via thermogravimetric analysis.

    Science.gov (United States)

    Dhyani, Vaibhav; Kumar, Jitendra; Bhaskar, Thallada

    2017-12-01

    The thermal decomposition of sorghum straw was investigated by non-isothermal thermogravimetric analysis, where the determination of kinetic triplet (activation energy, pre-exponential factor, and reaction model), was the key objective. The activation energy was determined using different isoconversional methods: Friedman, Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS), Starink, Iterative method of Chai & Chen, Vyazovkin AIC method, and Li & Tang equation. The pre-exponential factor was calculated using Kissinger's equation; while the reaction model was predicted by comparison of z-master plot obtained from experimental values with the theoretical plots. The values of activation energy obtained from isoconversional methods were further used for evaluation of thermodynamic parameters, enthalpy, entropy and Gibbs free energy. Results showed three zones of pyrolysis having average activation energy values of 151.21kJ/mol, 116.15kJ/mol, and 136.65kJ/mol respectively. The data was well fitting with two-dimension 'Valensi' model for conversion values from 0 to 0.4 with a coefficient of determination (R 2 ) value of 0.988, and with third order reaction model for values from 0.4 to 0.9 with an R 2 value of 0.843. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Thermogravimetric and differential thermal analysis of potassium bicarbonate contaminated cellulose

    Science.gov (United States)

    A. Broido

    1966-01-01

    When samples undergo a complicated set of simultaneous and sequential reactions, as cellulose does on heating, results of thermogravimetric and differential thermal analyses are difficult to interpret. Nevertheless, careful comparison of pure and contaminated samples, pyrolyzed under identical conditions, can yield useful information. In these experiments TGA and DTA...

  7. Thermal decomposition characteristics of microwave liquefied rape straw residues using thermogravimetric analysis

    Science.gov (United States)

    Xingyan Huang; Cornelis F. De Hoop; Jiulong Xie; Chung-Yun Hse; Jinqiu Qi; Yuzhu Chen; Feng Li

    2017-01-01

    The thermal decomposition characteristics of microwave liquefied rape straw residues with respect to liquefaction condition and pyrolysis conversion were investigated using a thermogravimetric (TG) analyzer at the heating rates of 5, 20, 50 °C min-1. The hemicellulose decomposition peak was absent at the derivative thermogravimetric analysis (DTG...

  8. Thermogravimetric study and kinetic analysis of dried industrial sludge pyrolysis.

    Science.gov (United States)

    Liu, Guangrui; Song, Huijuan; Wu, Jinhu

    2015-07-01

    Thermogravimetric experiments of two different industrial sludge samples were carried out with non-isothermal temperature programs. The results indicated that the pyrolysis process contains three obvious stages and the main decomposition reaction occurred in the range of 200-600°C. The distributed activation energy model (DAEM) was also proposed describing equally well the pyrolysis behavior of the samples. The calculated activation energy was ranged from 170 to 593kJ/mol and 125 to 756kJ/mol for SLYG (sludge sample from chemical fiber factory) and SQD (sludge sample from woody industry), respectively. The reliability of this model not only provided good fit for all experiments, but also allowed accurate extrapolations to relative higher heating rates. Besides, the FTIR measurement was also used to further understand the relationship between pyrolysis behavior and chemical structures for industrial sludge. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Thermal and Chemical Characterization of Non-Metallic Materials Using Coupled Thermogravimetric Analysis and Infrared Spectroscopy

    Science.gov (United States)

    Huff, Timothy L.

    2002-01-01

    Thermogravimetric analysis (TGA) is widely employed in the thermal characterization of non-metallic materials, yielding valuable information on decomposition characteristics of a sample over a wide temperature range. However, a potential wealth of chemical information is lost during the process, with the evolving gases generated during thermal decomposition escaping through the exhaust line. Fourier Transform-Infrared spectroscopy (FT-IR) is a powerful analytical technique for determining many chemical constituents while in any material state, in this application, the gas phase. By linking these two techniques, evolving gases generated during the TGA process are directed into an appropriately equipped infrared spectrometer for chemical speciation. Consequently, both thermal decomposition and chemical characterization of a material may be obtained in a single sample run. In practice, a heated transfer line is employed to connect the two instruments while a purge gas stream directs the evolving gases into the FT-IR. The purge gas can be either high purity air or an inert gas such as nitrogen to allow oxidative and pyrolytic processes to be examined, respectively. The FT-IR data is collected realtime, allowing continuous monitoring of chemical compositional changes over the course of thermal decomposition. Using this coupled technique, an array of diverse materials has been examined, including composites, plastics, rubber, fiberglass epoxy resins, polycarbonates, silicones, lubricants and fluorocarbon materials. The benefit of combining these two methodologies is of particular importance in the aerospace community, where newly developing materials have little available data with which to refer. By providing both thermal and chemical data simultaneously, a more definitive and comprehensive characterization of the material is possible. Additionally, this procedure has been found to be a viable screening technique for certain materials, with the generated data useful in

  10. Research on Mechanism of Paper Burning by Thermogravimetric Analysis

    Institute of Scientific and Technical Information of China (English)

    QIN Da; HAN Xingzhou; WANG Xiaoguang; QI Fengliang; WANG Zijie; GUO Zihan; HAO Hongguang

    2015-01-01

    The examination of charred document is a challenge and usually requires a careful application of certain scientific techniques due to its unstable property. To address this issue, the mechanism of paper burning was studied in this paper. Here thermal-gravimetry (TG) was applied to investigate five kinds of paper, along with their TG and derivative thermogravimetric curve (DTG) observed at different atmospheric conditions. The results showed that the shape of curves, albeit similar, varied with the physical and chemical composition of paper. In the burning process, dehydration and de-polymerization are the two main pathways for cellulose, the major ingredient of paper. The heating rate indicated little influence on the curves while the sort of atmosphere worked strongly. The reason is due to the lack of tar oxidation when nitrogen used as the atmospheric environment. At moderate temperature, de-polymerization prevails and the tar can be observed. With temperature increasing, the tar and cellulose are further decomposed, leading to products of high boiling-point. According to the results, the charred document can be classified as one of the dehydrated, tarred, charred and ashed. Except the ashed stage, the other three can be handled and the writing whereon can be deciphered. The results exposed hereof may provide a fundamental for examining and deciphering charred document.

  11. Synthesis, spectroscopic characterization and thermogravimetric analysis of two series of substituted (metallotetraphenylporphyrins

    Directory of Open Access Journals (Sweden)

    Rasha K. Al-Shewiki

    2017-06-01

    Full Text Available Subsequent treatment of H2TPP(CO2H4 (tetra(p-carboxylic acid phenylporphyrin, 1 with an excess of oxalyl chloride and HNR2 afforded H2TPP(C(ONR24 (R = Me, 2; iPr, 3 with yields exceeding 80%. The porphyrins 2 and 3 could be converted to the corresponding metalloporphyrins MTPP(C(ONR24 (R = Me/iPr for M = Zn (2a, 3a; Cu (2b, 3b; Ni (2c, 3c; Co (2d, 3d by the addition of 3 equiv of anhydrous MCl2 (M = Zn, Cu, Ni, Co to dimethylformamide solutions of 2 and 3 at elevated temperatures. Metalloporphyrins 2a–d and 3a–d were obtained in yields exceeding 60% and have been, as well as 2 and 3, characterized by elemental analysis, electrospray ionization mass spectrometry (ESIMS and IR and UV–vis spectroscopy. Porphyrins 2, 2a–d and 3, 3a–d are not suitable for organic molecular beam deposition (OMBD, which is attributed to their comparatively low thermal stability as determined by thermogravimetric analysis (TG of selected representatives.

  12. Synthesis, spectroscopic characterization and thermogravimetric analysis of two series of substituted (metallo)tetraphenylporphyrins.

    Science.gov (United States)

    Al-Shewiki, Rasha K; Mende, Carola; Buschbeck, Roy; Siles, Pablo F; Schmidt, Oliver G; Rüffer, Tobias; Lang, Heinrich

    2017-01-01

    Subsequent treatment of H 2 TPP(CO 2 H) 4 (tetra( p -carboxylic acid phenyl)porphyrin, 1 ) with an excess of oxalyl chloride and HNR 2 afforded H 2 TPP(C(O)NR 2 ) 4 (R = Me, 2 ; iPr, 3 ) with yields exceeding 80%. The porphyrins 2 and 3 could be converted to the corresponding metalloporphyrins MTPP(C(O)NR 2 ) 4 (R = Me/iPr for M = Zn ( 2a , 3a ); Cu ( 2b , 3b ); Ni ( 2c , 3c ); Co ( 2d , 3d )) by the addition of 3 equiv of anhydrous MCl 2 (M = Zn, Cu, Ni, Co) to dimethylformamide solutions of 2 and 3 at elevated temperatures. Metalloporphyrins 2a - d and 3a - d were obtained in yields exceeding 60% and have been, as well as 2 and 3 , characterized by elemental analysis, electrospray ionization mass spectrometry (ESIMS) and IR and UV-vis spectroscopy. Porphyrins 2 , 2a - d and 3 , 3a - d are not suitable for organic molecular beam deposition (OMBD), which is attributed to their comparatively low thermal stability as determined by thermogravimetric analysis (TG) of selected representatives.

  13. Thermogravimetric analysis in the characterization of colombian coals used in the production of coke

    International Nuclear Information System (INIS)

    Guerrero, Camilo; Salamanca, Monica E; Diaz, Jose de J

    2010-01-01

    Five types of coal from the states of Cundinamarca, Boyaca and Norte de Santander (Colombia) were characterized by proximate, ultimate, rheological, petrographic, calorific and thermogravimetric analysis. The parameters used, especially the ones which determine the rheological properties show that the studied coals and its blends could produce good quality coke. It was observed the inverse relationship between the volatile matter content and the mean vitrinite reflectance, relationship which is attributed to the increase of the aromaticity in the molecular structure of the coal as a consequence of the rank increase. The parameters derived from the thermogravimetric analysis, maximum velocity of de-volatilization and the temperature of maximum velocity of de-volatilization and the media reflectance of the vitrinite showed good correlations. Also was observed an interesting correlation between the velocity of de-volatilization and maximum fluidity. This shows that the thermogravimetric analysis can be a useful tool to characterize in a quick way coals used for metallurgical coke production.

  14. Characterization of an alkali-treated grass fiber by thermogravimetric and X-ray crystallographic analysis

    NARCIS (Netherlands)

    De, D.; De, Debapriya

    2008-01-01

    The thermal behavior of grass fiber was characterized by means of thermogravimetric analysis and differential scanning calorimetry analysis. The results proved that the removal of water-soluble matter improved the thermal behavior of grass fiber over that of unleached fiber, and this was further

  15. Thermogravimetric and Kinetic Analysis of Cassava Starch Based Bioplastic

    Directory of Open Access Journals (Sweden)

    Nanang Eko Wahyuningtyas

    2017-11-01

    Full Text Available Cassava starch based bioplasticfor packaging application has great potency because of the various starch-producing plants in Indonesia.Bioplasticcan contribute to reduce the dependence on fossil fuels andpetroleumthat can solve the environmentalproblem.Thepurpose of this research is to find out the thermal decomposition and the activation energy of cassava starch based bioplastic. The methods weresynthesis bioplastic with cassava starch as main component and glycerol as plasticizer. The thermogravimetry analysis was conducted to obtain the decomposition process mechanism of bioplastic and the heating valueof bioplasticwas measured  using theadiabatic bomb calorimetric.  Data analysis was conducted using  a fitting model approach with an acikalin method to determine the activation energy. The result of thethermogravimetricanalysis showed thatbioplasticisgraduallydecomposedto the moisture, volatilematter, fixed carbon, andash in four stages mechanism. Totally decomposition of bioplastic was 530°C, then all of bioplastic was become the ash. The activation energy in the early and primary thermal decomposition stages are 1.27 kJ/moland 22.62 kJ/mol, respectively and heating valueof bioplastic is 15.16 MJ/kg.

  16. Thermogravimetric and Kinetic Analysis of Raw and Torrefied Biomass Combustion

    Directory of Open Access Journals (Sweden)

    Kopczyński Marcin

    2015-06-01

    Full Text Available The use of torrefied biomass as a substitute for untreated biomass may decrease some technological barriers that exist in biomass co-firing technologies e.g. low grindability, high moisture content, low energy density and hydrophilic nature of raw biomass. In this study the TG-MS-FTIR analysis and kinetic analysis of willow (Salix viminalis L. and samples torrefied at 200, 220, 240, 260, 280 and 300 °C (TSWE 200, 220, 240, 260, 280 and 300, were performed. The TG-DTG curves show that in the case of willow and torrefied samples TSWE 200, 220, 240 and 260 there are pyrolysis and combustion stages, while in the case of TSWE 280 and 300 samples the peak associated with the pyrolysis process is negligible, in contrast to the peak associated with the combustion process. Analysis of the TG-MS results shows m/z signals of 18, 28, 29 and 44, which probably represent H2O, CO and CO2. The gaseous products were generated in two distinct ranges of temperature. H2O, CO and CO2 were produced in the 500 K to 650 K range with maximum yields at approximately 600 K. In the second range of temperature, 650 K to 800 K, only CO2 was produced with maximum yields at approximately 710 K as a main product of combustion process. Analysis of the FTIR shows that the main gaseous products of the combustion process were H2O, CO2, CO and some organics including bonds: C=O (acids, aldehydes and ketones, C=C (alkenes, aromatics, C-O-C (ethers and C-OH. Lignin mainly contributes hydrocarbons (3000-2800 cm−1, while cellulose is the dominant origin of aldehydes (2860-2770 cm−1 and carboxylic acids (1790-1650 cm−1. Hydrocarbons, aldehydes, ketones and various acids were also generated from hemicellulose (1790-1650 cm−1. In the kinetic analysis, the two-steps first order model (F1F1 was assumed. Activation energy (Ea values for the first stage (pyrolysis increased with increasing torrefaction temperature from 93 to 133 kJ/mol, while for the second stage (combustion it

  17. Kinetics of devolatilisation of forestry wastes from thermogravimetric analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lapuerta, M.; Hernandez, J.J. [Universidad de Castilla-La Mancha, Ciudad real (Spain). Escuela Tecnica Superior de Ingenieros Industriales; Rodriguez, J.J. [Repsol-YPF, Puertollano (Spain). Chemical Department

    2004-10-01

    The great potential of Maritime pine (Pinus pinaster) wastes in the middle regions of Spain has motivated an increasing interest about the energy use of this material, either through combustion or gasification processes. Samples of these biomass wastes have been analysed by thermogravimetry under both inert and oxidant atmospheres, from room temperature up to 1100 K, at different heating rates: 10, 30, 40, 50 and 60 K min{sup -1}. An estimation of the proximate analysis of the samples was made from combination of both resulting weight loss curves. The devolatilisation process of the samples was divided into three non-interacting mass-loss events described as parallel first-order reactions, being the first event identified as the moisture loss process, the second one as the hemicellulose and cellulose decomposition process and the third one as that of lignin decomposition. A fitting algorithm to obtain the kinetic parameters permitted a good agreement with experimental results, as well as a good discrimination of the effect of the heating rate. Due to the non-homogeneous nature of the tested samples, the use of other conventional methods for obtaining the kinetic parameters has been proved to be inadequate. (author)

  18. Thermogravimetric analysis and thermal degradation behaviour of advanced PMR-X carbon fiber composites

    International Nuclear Information System (INIS)

    Rngie, M.

    2003-01-01

    Thermal degradation behavior of sized and unsized carbon fibers in polyimide matrix was investigated. Degradation of neat resin and unidirectional laminates were investigated by thermogravimetric analysis technique at temperatures between 470 d ig C -650 d ig C and up to 250 h rs. Isothermal ageing of the PMR-X composite samples under different test conditions (i. e. different temperatures and prolonged aging times), showed that oxidation and degradation occurs in stage three different rates. Thermogravimetric analysis showed that the cured PMR-X composite panels are more stable in an inert atmosphere (nitrogen atmosphere)than in air and the degradation of neat resin is much higher than the composite samples. However, the rate of degradation of the unsized untreated carbon fibers in nitrogen environment is much higher than that for the PMR-X composites containing sized fibers

  19. Uncertainty Determination Methodology, Sampling Maps Generation and Trend Studies with Biomass Thermogravimetric Analysis

    Science.gov (United States)

    Pazó, Jose A.; Granada, Enrique; Saavedra, Ángeles; Eguía, Pablo; Collazo, Joaquín

    2010-01-01

    This paper investigates a method for the determination of the maximum sampling error and confidence intervals of thermal properties obtained from thermogravimetric analysis (TG analysis) for several lignocellulosic materials (ground olive stone, almond shell, pine pellets and oak pellets), completing previous work of the same authors. A comparison has been made between results of TG analysis and prompt analysis. Levels of uncertainty and errors were obtained, demonstrating that properties evaluated by TG analysis were representative of the overall fuel composition, and no correlation between prompt and TG analysis exists. Additionally, a study of trends and time correlations is indicated. These results are particularly interesting for biomass energy applications. PMID:21152292

  20. Strategy for thermo-gravimetric analysis of K East fuel samples

    International Nuclear Information System (INIS)

    Lawrence, L.A.

    1997-01-01

    A strategy was developed for the Thermo-Gravimetric Analysis (TGA) testing of K East fuel samples for oxidation rate determinations. Tests will first establish if there are any differences for dry air oxidation between the K West and K East fuel. These tests will be followed by moist inert gas oxidation rate measurements. The final series of tests will consider pure water vapor i.e., steam

  1. Thermogravimetric analysis of silicon carbide-silicon nitride fibers at ambient to 1000 C in air

    Science.gov (United States)

    Daniels, J. G.; Ledbetter, F. E., III; Clemons, J. M.; Penn, B. G.

    1984-01-01

    Thermogravimetric analysis of silicon carbide-silicon nitride fibers was carried out at ambient to 1000 C in air. The weight loss over this temperature range was negligible. In addition, the oxidative stability at high temperature for a short period of time was determined. Fibers heated at 1000 C in air for fifteen minutes showed negligible weight loss (i.e., less than 1 percent).

  2. Thermogravimetric analysis of the polymer acrylate-vinyl ether mixture cured by radiation

    International Nuclear Information System (INIS)

    Danu, Sugiarto

    1998-01-01

    An experiment on thermal stability of the polymer acrylate-vinyl ether mixture cured by radiation have been done using thermogravimetric analysis. Three kinds of acrylic oligomers i.e., epoxy acrylate, urethane acrylate, and polypropylene glycol diacrylate, and vinyl ether monomers i.e., triethylene glycol divinyl ether (DVE-3), 1,4-cyclohexane dimethanol divinyl ether (CHVE), and butanediol monovinyl ether (HBVE) were used in the experiment. Reaction was taken via radical and cationic polymerisation. In case of cationic polymerisation, diphenyliodonium hexafluorophosphate fotoinisiator was used in the formulation. Thermogravimetric analysis was conducted in a nitrogen atmosphere at a flow rate of 40 ml/minute with a constant heating rate 10 o C and evaluation range were done from 25 to 500 o C. The results of thermogravimetric analysis showed that acrylate and DVE-3 mixture produced the polymer films with higher thermal stability than the mixture of acrylate with CHVE or HBVE. The composition of acrylate-vinyl ether mixture and degree of unsaturation of vinyl ether monomers influenced the thermal stability of polymer. The mixture of epoxy acrylate-vinyl ether and polypropylene glycol diacrylate-vinyl ether have 1 initial decomposition temperature whereas the urethane acrylate-vinyl ether mixture has 2 initial decomposition temperatures. (authors)

  3. Purity Evaluation of Single-Walled Carbon Nanotubes Using Thermogravimetric Analysis

    International Nuclear Information System (INIS)

    Goak, Jeung Choon; Kim, Tae Yang; Jung, Jongwan; Seo, Young-Soo; Lee, Naesung; Sok, Junghyun

    2013-01-01

    This study evaluated the purity of single-walled carbon nanotubes (SWCNTs) in the arc-synthesized SWCNT samples by using thermogravimetric analysis (TGA). The as-produced SWCNT samples were heat-treated in air for 20 h at 275-475°C and characterized by scanning and transmission electron microscopes and TGA to establish oxidation temperature ranges of SWCNTs and carbonaceous impurities comprising the samples. Based on these oxidation temperature ranges, derivative thermogravimetric curves were deconvoluted, and differentiated peaks were assigned to SWCNTs and carbonaceous impurities. The compositions and the SWCNT purities of the samples were obtained simply by calculating the areal ratios under the deconvoluted curves. TGA studies on purity evaluation and thermal stabilities of SWCNTs and carbonaceous impurities are likely to provide us with a simple route of thermal oxidation purification to acquire high-purity SWCNT samples.

  4. A comprehensive physicochemical, thermal, and spectroscopic characterization of zinc (II) chloride using X-ray diffraction, particle size distribution, differential scanning calorimetry, thermogravimetric analysis/differential thermogravimetric analysis, ultraviolet-visible, and Fourier transform-infrared spectroscopy.

    Science.gov (United States)

    Trivedi, Mahendra Kumar; Sethi, Kalyan Kumar; Panda, Parthasarathi; Jana, Snehasis

    2017-01-01

    Zinc chloride is an important inorganic compound used as a source of zinc and has other numerous industrial applications. Unfortunately, it lacks reliable and accurate physicochemical, thermal, and spectral characterization information altogether. Hence, the authors tried to explore in-depth characterization of zinc chloride using the modern analytical technique. The analysis of zinc chloride was performed using powder X-ray diffraction (PXRD), particle size distribution, differential scanning calorimetry (DSC), thermogravimetric analysis/differential thermogravimetric analysis (TGA/DTG), ultraviolet-visible spectroscopy (UV-vis), and Fourier transform-infrared (FT-IR) analytical techniques. The PXRD patterns showed well-defined, narrow, sharp, and the significant peaks. The crystallite size was found in the range of 14.70-55.40 nm and showed average crystallite size of 41.34 nm. The average particle size was found to be of 1.123 ( d 10 ), 3.025 ( d 50 ), and 6.712 ( d 90 ) μm and average surface area of 2.71 m 2 /g. The span and relative span values were 5.849 μm and 1.93, respectively. The DSC thermogram showed a small endothermic inflation at 308.10°C with the latent heat (ΔH) of fusion 28.52 J/g. An exothermic reaction was observed at 449.32°C with the ΔH of decomposition 66.10 J/g. The TGA revealed two steps of the thermal degradation and lost 8.207 and 89.72% of weight in the first and second step of degradation, respectively. Similarly, the DTG analysis disclosed T max at 508.21°C. The UV-vis spectrum showed absorbance maxima at 197.60 nm (λ max ), and FT-IR spectrum showed a peak at 511/cm might be due to the Zn-Cl stretching. These in-depth, comprehensive data would be very much useful in all stages of nutraceuticals/pharmaceuticals formulation research and development and other industrial applications.

  5. Thermogravimetric analysis coupled with chemometrics as a powerful predictive tool for ß-thalassemia screening.

    Science.gov (United States)

    Risoluti, Roberta; Materazzi, Stefano; Sorrentino, Francesco; Maffei, Laura; Caprari, Patrizia

    2016-10-01

    β-Thalassemia is a hemoglobin genetic disorder characterized by the absence or reduced β-globin chain synthesis, one of the constituents of the adult hemoglobin tetramer. In this study the possibility of using thermogravimetric analysis (TGA) followed by chemometrics as a new approach for β-thalassemia detection is proposed. Blood samples from patients with β-thalassemia were analyzed by the TG7 thermobalance and the resulting curves were compared to those typical of healthy individuals. Principal Component Analysis (PCA) was used to evaluate the correlation between the hematological parameters and the thermogravimetric results. The thermogravimetric profiles of blood samples from β-thalassemia patients were clearly distinct from those of healthy individuals as result of the different quantities of water content and corpuscular fraction. The hematological overview showed significant decreases in the values of red blood cell indices and an increase in red cell distribution width value in thalassemia subjects when compared with those of healthy subjects. The implementation of a predictive model based on Partial Least Square Discriminant Analysis (PLS-DA) for β-thalassemia diagnosis, was performed and validated. This model permitted the discrimination of anemic patients and healthy individuals and was able to detect thalassemia in clinically heterogeneous patients as in the presence of δβ-thalassemia and β-thalassemia combined with Hb Lepore. TGA and Chemometrics are capable of predicting ß-thalassemia syndromes using only a few microliters of blood without any pretreatment and with an hour of analysis time. A fast, rapid and cost-effective diagnostic tool for the β-thalassemia screening is proposed. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Thermogravimetric analysis of anthracite and waste plastics by iso-conversional method

    International Nuclear Information System (INIS)

    Ren, Shan; Zhang, Jianliang

    2013-01-01

    Highlights: • Co-combustion kinetic analysis of solid fuels was made by iso-conversional method. • Thermodynamic and kinetic parameters of combustion for blends were determined. • WP can improve the combustion characteristic of high ash anthracite. • Reasonable utilization the energy of WP is important for industrial production. - Abstract: Combustion mechanisms and kinetics of plastics-coal blends with 0, 10, 20, 40 and 100% waste plastics (WP) are studied separately by thermogravimetric analysis (TGA) from ambient temperature to 900 °C in air atmosphere. These blends are combusted at different heating rates. The results indicate that, with the increase of waste plastics content, the combustion processes of blends could be divided into one stage, two stages, three stages and one stage. Meanwhile, the ignition and final temperatures of them both decrease. The maximum weight loss rate of WP is much higher than that of other samples. The iso-conversional method is used for the kinetic analysis of the non-isothermal thermogravimetric data and results indicate that, when the waste plastics content varied from 0% to 40%, the values of activation energy increase from 113.3 kJ mol −1 to 156.0 kJ mol −1 , and the value of activation energy for pure WP is 278.8 kJ mol −1

  7. Determination of nanoparticle surface coatings and nanoparticle purity using microscale thermogravimetric analysis.

    Science.gov (United States)

    Mansfield, Elisabeth; Tyner, Katherine M; Poling, Christopher M; Blacklock, Jenifer L

    2014-02-04

    The use of nanoparticles in some applications (i.e., nanomedical, nanofiltration, or nanoelectronic) requires small samples with well-known purities and composition. In addition, when nanoparticles are introduced into complex environments (e.g., biological fluids), the particles may become coated with matter, such as proteins or lipid layers. Many of today's analytical techniques are not able to address small-scale samples of nanoparticles to determine purity and the presence of surface coatings. Through the use of an elevated-temperature quartz crystal microbalance (QCM) method we call microscale thermogravimetric analysis, or μ-TGA, the nanoparticle purity, as well as the presence of any surface coatings of nanomaterials, can be measured. Microscale thermogravimetric analysis is used to determine the presence and amount of surface-bound ligand coverage on gold nanoparticles and confirm the presence of a poly(ethylene glycol) coating on SiO2 nanoparticles. Results are compared to traditional analytical techniques to demonstrate reproducibility and validity of μ-TGA for determining the presence of nanoparticle surface coatings. Carbon nanotube samples are also analyzed and compared to conventional TGA. The results demonstrate μ-TGA is a valid method for quantitative determination of the coatings on nanoparticles, and in some cases, can provide purity and compositional data of the nanoparticles themselves.

  8. Kinetic Model of LiFePO4 Formation Using Non-Isothermal Thermogravimetric Analysis

    Directory of Open Access Journals (Sweden)

    Abdul Halim

    2014-03-01

    Full Text Available The formation reaction of LiFePO4 from decomposition of precursors LiOH, FeSO4.7H2O and (NH42HPO4 with mol ratio of Li:Fe:P=1:1:1 was investigated. The experiment was carried out by thermogravimetric differential thermal analysis (TG-DTA method using nitrogen as atmosfer at a constant heating rate to obtain kinetic constant parameters. Several heating rates were selected, there are 5, 7, 10, 15, 17.5, 22.5 and 25 °C/min. Activation energy, pre-exponential factor and reaction order were taken using Kissinger method and obtained respectively 56.086 kJ/mol, 6.95×108 min-1, and 1.058. Based on fitting result between reaction model and experiment were obtained that reaction obeyed the three dimension diffusion model. © 2014 BCREC UNDIP. All rights reservedReceived: 19th September 2013; Revised: 9th December 2013; Accepted: 23rd January 2014 [How to Cite: Halim, A., Widiyastuti, W., Setyawan, H., Winardi, S. (2014. Kinetic of LiFePO4 For-mation Using Non-isothermal Thermogravimetric Analysis. Bulletin of Chemical Reaction Engineering & Catalysis, 9 (1: 60-65. (doi:10.9767/bcrec.9.1.5508.60-65][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.9.1.5508.60-65] 

  9. Pyrolysis of coal, biomass and their blends: performance assessment by thermogravimetric analysis.

    Science.gov (United States)

    Ferrara, Francesca; Orsini, Alessandro; Plaisant, Alberto; Pettinau, Alberto

    2014-11-01

    With the aim to support the experimental tests in a gasification pilot plant, the thermal decomposition of coal, biomass and their mixtures has been carried out through a thermogravimetric analysis (TGA) and a simplified kinetic analysis. The TGA of pure fuels indicates the low reactivity of South African coal and the relatively high reactivity of Sardinian Sulcis coal during pyrolysis. Among the tested fuels, biomass (stone pine wood chips) is the most reactive one. These results fully confirm those obtained during the experimental tests in the gasification pilot plant. As for the fuel blends, the analysis shows that the synergic effects between the considered coals and biomass are negligible when they are co-pyrolyzed. The results of the analysis confirm that TGA could be very useful to generally predict the gasification performance and to optimize the experimental campaigns in pilot-scale gasification plants. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Thermal behavior and kinetics assessment of ethanol/gasoline blends during combustion by thermogravimetric analysis

    International Nuclear Information System (INIS)

    3, CEP 12.516-410 Guaratinguetá, SP (Brazil); U.T.P. – Universidad Tecnológica de Pereira, Faculty of Mechanical Engineering, Pereira, Risaralda (Colombia))" data-affiliation=" (UNESP – Univ Estadual Paulista, Campus of Guaratinguetá, Department of Energy, Laboratory of Combustion and Carbon Capture LC3, CEP 12.516-410 Guaratinguetá, SP (Brazil); U.T.P. – Universidad Tecnológica de Pereira, Faculty of Mechanical Engineering, Pereira, Risaralda (Colombia))" >Rios Quiroga, Luis Carlos; 3, CEP 12.516-410 Guaratinguetá, SP (Brazil))" data-affiliation=" (UNESP – Univ Estadual Paulista, Campus of Guaratinguetá, Department of Energy, Laboratory of Combustion and Carbon Capture LC3, CEP 12.516-410 Guaratinguetá, SP (Brazil))" >Balestieri, José 3, CEP 12.516-410 Guaratinguetá, SP (Brazil))" data-affiliation=" (UNESP – Univ Estadual Paulista, Campus of Guaratinguetá, Department of Energy, Laboratory of Combustion and Carbon Capture LC3, CEP 12.516-410 Guaratinguetá, SP (Brazil))" >Antonio Perrella; 3, CEP 12.516-410 Guaratinguetá, SP (Brazil))" data-affiliation=" (UNESP – Univ Estadual Paulista, Campus of Guaratinguetá, Department of Energy, Laboratory of Combustion and Carbon Capture LC3, CEP 12.516-410 Guaratinguetá, SP (Brazil))" >Ávila, Ivonete

    2017-01-01

    Highlights: • Kinetic parameters of thermal decomposition events were obtained. • Thermal analysis was used as a tool for understanding combustion processes. • Blends would be classified using thermogravimetric analysis technics. • Synergistic effect of ethanol mixed with gasoline was studied and defined. • Relative error and activation energy values were used to analyze the synergy. - Abstract: The use of ethanol as a fuel or as an additive blended with gasoline is very important for most countries, which aim to reduce the heavy dependence on fossil fuels and mitigate greenhouse gases emission. An increased use of ethanol-gasoline blends has placed great relevance on acquiring knowledge about their physical and chemical properties. Thus, knowledge of such properties favors a better understanding of the effect of the percentage of ethanol/gasoline blends on engine performance. Thence, the present study has established a correlation between activation energy and synergetic effects, obtained by a thermal analysis, and ethanol content in gasoline for different blends in order to use this technique as a tool to classify these blends in the process in order to obtain useful energy in spark ignition engines. For such a purpose, a kinetic study has been conducted through a simultaneous thermal analysis system – TGA (thermogravimetry analysis) and DTA (differential thermal analysis) by following the methodology of non-isothermal tests. Thermogravimetric tests were performed and fuel activation energies for gasoline, ethanol, and percentages of 5, 10, 15, 20, 25, 30, 50, and 75% (%v) ethanol mixed with gasoline, which was achieved by the model free kinetics. The analysis results suggest that the theoretical curves characteristics of the thermal decomposition of ethanol-gasoline blends are rather different due to their ethanol content. Furthermore, it was observed significant interactions and synergistic effects, especially regarding those with low ethanol

  11. Thermal analysis of thermo-gravimetric measurements of spent nuclear fuel oxidation rates

    International Nuclear Information System (INIS)

    Cramer, E.R.

    1997-01-01

    A detailed thermal analysis was completed of the sample temperatures in the Thermo-Gravimetric Analysis (TGA) system used to measure irradiated N Reactor fuel oxidation rates. Sample temperatures during the oxidation process did not show the increase which was postulated as a result of the exothermic reactions. The analysis shows the axial conduction of heat in the sample holder effectively removes the added heat and only a very small, i.e., <10 C, increase in temperature is calculated. A room temperature evaporation test with water showed the sample thermocouple sensitivity to be more than adequate to account for a temperature change of approximately 5 C. Therefore, measured temperatures in the TGA are within approximately 10 C of the actual sample temperatures and no adjustments to reported data to account for the heat input from the oxidation process are necessary

  12. Mechanism study on cellulose pyrolysis using thermogravimetric analysis coupled with infrared spectroscopy

    Institute of Scientific and Technical Information of China (English)

    WANG Shurong; LIU Qian; LUO Zhongyang; WEN Lihua; CEN Kefa

    2007-01-01

    Based on the investigation of the polysaccharide structure of cellulose by using Fourier transform spectrum analysis,the pyrolysis behaviour of cellulose was studied at a heating rate of 20 K/min by thermogravimetric (TG) analysis coupled with Fourier transform infrared (FTIR) spectroscopy.Experimental results show that the decomposition of cellulose mainly occurs at the temperature range of 550-670 K.The weight loss becomes quite slow when the temperature increases further up to 680 K and the amount of residue reaches a mass percent of 14.7%.The FTIR analysis shows that free water is released first during cellulose pyrolysis,followed by depolymerization and dehydration.Glucosidic bond and carbon-carbon bond break into a series of hydrocarbons,alcohols,aldehydes,acids,etc.Subsequently these large-molecule compounds decompose further into gases,such as methane and carbon monoxide.

  13. Investigation of Thermal Behavior for Natural Fibres Reinforced Epoxy using Thermogravimetric and Differential Scanning Calorimetric Analysis

    Directory of Open Access Journals (Sweden)

    Fauzi F.A.

    2016-01-01

    Full Text Available This paper presented the research works on the investigation of the thermal behavior of the natural fibres; i.e. pineapple leaf fibre, kenaf fibre and mengkuang fibres reinforced epoxy. The thermogravimetric analysis and differential scanning calorimetric analysis were used to measure the thermal behavior of the treated and untreated pineapple, kenaf and mengkuang fibres reinforced epoxy. The samples for both analysis were subjected to maximum temperature 600°C at the heating rate of 10°C/min. The results showed that the treated fibres show higher maximum peak temperature as compared to the untreated fibres. Additionally, the glass transition temperature showed a lower value for all treated fibre. It can be concluded that investigation of thermal properties of these natural fibres could improve the utilization of natural fibre composites in various applications i.e. sports applications.

  14. Thermogravimetric Analysis and Kinetic Study on Pyrolysis of Veteri-narian Solid Waste

    Directory of Open Access Journals (Sweden)

    Andrés Felipe Rojas González

    2016-10-01

    Full Text Available Context: Institutional waste from clinical centers can be classified as those coming from health institutions dedicated to human attention and those coming from centers for animal veterinary care. The latter are mainly hazardous wastes, hence their disposal requires incineration. Most of such waste is organic, and it is possible, therefore, to take advantage of their energetic power in combustion or pyrolysis processes. This work is motivated because no literature was found on the pyrolysis kinetics veterinary waste, as this kind of studies are mainly focused on hospital waste of human health care. Method: The kinetics of pyrolysis is characterized and studied by means of thermogravimetric analysis of 6 major veterinary waste (gauze, cotton swabs, cotton, nails, hair, plastic syringes. The characterization is performed by proximate and elemental analysis, and thermogravimetric analysis. Reactivity characteristics and pyrolytic capability of wastes are established. The kinetics study on pyrolysis was carried out by determining the kinetic triplet by isoconversional Starink method. Results: It was established that the pyrolysis index increases with the heating rate and that the thermal degradation depends on the material type of the waste. Similarly, it was found that the temperature (ΔT = Tf - Ti for the thermal decomposition of veterinary waste is: ΔTnails> ΔThair > ΔTcotton swabs > ΔTgauze > ΔTcotton > ΔTplastic syringes; the activation energy is Enails> E hair > Eplastic syringes > Ecotton swabs > E gauze > Ecotton, and the reaction order is: n hair > nnails > ncotton swabs > ncotton > n gauze > n plastic syringes. Conclusions: These results suggest the possibility of using veterinary wastes for power generation, providing an alternative for sustainable energy development to cities in continuous growth, from both, energetic and environmental points of view.

  15. Thermogravimetric analysis of phase transitions in cement compositions mixed by sodium silicate solution

    Directory of Open Access Journals (Sweden)

    Fedosov Sergey Viktorovich

    2014-01-01

    Full Text Available This paper presents a study of the capability to modify cement by mechanical activation of sodium silicate water solution. Admixtures or blends of binding agents were employed for modifying concrete properties. The liquid glass is applied to protect from chemically or physically unfavorable environmental impacts, such as acidic medium and high temperature. The sodium silicate is a high-capacity setting accelerator. The increasing of the liquid glass proportion in the mix leads to the degradation of the cement paste plasticity and for this reason it is necessary to reduce the amount of liquid glass in the cement paste. The activation of dilute water solution of sodium silicate into rotary pulsating apparatus directly before tempering of the cement paste is an effective way to decrease mass fraction of liquid glass in the cement paste. The results of the combined influence of liquid glass and mechanical activation on physicochemical processes taking place in cement stone are represented in this research. Thermogravimetric analysis was used in order to study cement blends. Thermogravimetric analysis of modified cement stone assays was performed by thermo analyzer SETARAM TGA 92-24. The results of the analysis of phase transition taking place under high-temperature heating of cement stone modified by the mechanical activation of the water solution of the sodium silicate were introduced. Thermograms of cement stone assays were obtained at different hardening age. The comparison of these thermograms allows us to come to a conclusion on the formation and the retention during long time of a more dense structure of the composite matrix mixed by the mechanical activation of sodium silicate water solution. The relation between the concrete composition and its strength properties was stated. Perhaps, the capability of modified concrete to keep calcium ions in sparingly soluble hydrosilicates leads to the increase in its durability and corrosion resistance.

  16. Thermogravimetric analysis of co-combustion between microalgae and textile dyeing sludge.

    Science.gov (United States)

    Peng, Xiaowei; Ma, Xiaoqian; Xu, Zhibin

    2015-03-01

    The synergistic interaction and kinetics of microalgae, textile dyeing sludge and their blends were investigated under combustion condition by thermogravimetric analysis. The textile dyeing sludge was blended with microalgae in the range of 10-90wt.% to investigate their co-combustion behavior. Results showed that the synergistic interaction between microalgae and textile dyeing sludge improved the char catalytic effect and alkali metals melt-induced effect on the decomposition of textile dyeing sludge residue at high temperature of 530-800°C. As the heating rate increasing, the entire combustion process was delayed but the combustion intensity was enhanced. The lowest average activation energy was obtained when the percentage of microalgae was 60%, which was 227.1kJ/mol by OFW and 227.4kJ/mol by KAS, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Characteristics and kinetic studies of Hydrilla verticillata pyrolysis via thermogravimetric analysis.

    Science.gov (United States)

    Hu, Zhiquan; Chen, Zhihua; Li, Genbao; Chen, Xiaojuan; Hu, Mian; Laghari, Mahmood; Wang, Xun; Guo, Dabin

    2015-10-01

    The pyrolysis characteristics and kinetic of Hydrilla verticillata (HV) have been investigated using non-isothermal thermogravimetric analysis. The results showed that the pyrolysis behavior of HV can be divided into two independent stages. The kinetics of Stage I was investigated using a distributed activation energy model (DAEM) with discrete 99 first-order reactions. Stage II was an independent stage which corresponds to the decomposition of calcium oxalate, whose kinetics was studied using iso-conversional method together with compensation effect and master-plots method. The activation energies ranged from 92.39 to 506.17 and 190.42 to 222.48 kJ/mol for the first and second stages respectively. Calculated data gave very good fit to the experimental data. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Acoustic emission analysis coupled with thermogravimetric experiments dedicated to high temperature corrosion studies on metallic alloys

    International Nuclear Information System (INIS)

    Serris, Eric; Al Haj, Omar; Peres, Veronique; Cournil, Michel; Kittel, Jean; Grosjean, Francois; Ropital, Francois

    2014-01-01

    High temperature corrosion of metallic alloys (like iron, nickel, zirconium alloys) can damage equipment of many industrial fields (refinery, petrochemical, nuclear..). Acoustic emission (AE) is an interesting method owing to its sensitivity and its non-destructive aspect to quantify the level of damage in use of these alloys under various environmental conditions. High temperature corrosive phenomena create stresses in the materials; the relaxation by cracks of these stresses can be recorded and analyzed using the AE system. The goal of our study is to establish an acoustic signals database which assigns the acoustic signals to the specific corrosion phenomena. For this purpose, thermogravimetric analysis (TGA) is coupled with acoustic emission (AE) devices. The oxidation of a zirconium alloy, zircaloy-4, is first studied using thermogravimetric experiment coupled to acoustic emission analysis at 900 C. An inward zirconium oxide scale, preliminary dense, then porous, grow during the isothermal isobaric step. The kinetic rate increases significantly after a kinetic transition (breakaway). This acceleration occurs with an increase of acoustic emission activity. Most of the acoustic emission bursts are recorded after the kinetic transition. Acoustic emission signals are also observed during the cooling of the sample. AE numerical treatments (using wavelet transform) completed by SEM microscopy characterizations allows us to distinguish the different populations of cracks. Metal dusting represents also a severe form of corrosive degradation of metal alloy. Iron metal dusting corrosion is studied by AE coupled with TGA at 650 C under C 4 H 10 + H 2 + He atmosphere. Acoustic emission signals are detected after a significant increase of the sample mass.

  19. Characteristics of curcumin using cyclic voltammetry, UV–vis, fluorescence and thermogravimetric analysis

    International Nuclear Information System (INIS)

    Masek, Anna; Chrzescijanska, Ewa; Zaborski, Marian

    2013-01-01

    Highlights: • Electrooxidation of curcumin was investigated with cyclic voltammetry. • The curcumin is irreversibly oxidized at the platinum electrode in anhydrous media. • Absorbance, fluorescence and thermogravimetric analysis of curcumin was studied. • The HOMO and Mapped Electron Densities were calculated using HyperChem. • Oxidation mechanism for curcumin proposed. -- Abstract: Curcumin, the yellow, primary bioactive component of turmeric, has recently received attention from chemists due its wide range of potential biological applications as an antioxidant, anti-inflammatory, and anti-carcinogenic agent. The electrochemical behaviour of curcumin at a platinum electrode has been studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The oxidation of curcumin is an irreversible process that proceeds in two steps in 0.1 M (C 4 H 9 ) 4 NClO 4 in acetonitrile. The process of oxidation and its kinetics have been investigated. The rate constant, electron transfer coefficient and diffusion coefficients for the electrochemical oxidation of curcumin were determined. A mechanism for the oxidation of curcumin is proposed. The data obtained are consistent with the current literature and suggest that voltammetric studies on mechanically transferred solids may be a convenient method for elucidating the electrochemical oxidation mechanisms of compounds in anhydrous media. Theoretical calculations regarding the optimization of curcumin, electronic properties like highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) were calculated using with HyperChem software by AM1 semi-empirical method. The properties of curcumin in a homogeneous environment were investigated using spectroscopic techniques and thermogravimetric analysis

  20. Thermogravimetric analysis of the co-combustion of paper mill sludge and municipal solid waste

    International Nuclear Information System (INIS)

    Hu, Shanchao; Ma, Xiaoqian; Lin, Yousheng; Yu, Zhaosheng; Fang, Shiwen

    2015-01-01

    Highlights: • Thermogravimetric analysis of paper mill sludge and municipal solid waste were studied. • The combustion of paper mill sludge could be improved by blending municipal solid waste. • There existed significant interaction during co-combustion of the blends. • The OFW and Starink methods were used to obtain the activation energy. • The average activation energy was the lowest by blending 20% municipal solid waste. - Abstract: The thermal characteristics and kinetics of paper mill sludge (PMS), municipal solid waste (MSW) and their blends in the combustion process were investigated in this study. The mass percentages of PMS in the blends were 10%, 30%, 50%, 70% and 90%, respectively. The experiments were carried out at different heating rates (10 °C/min, 20 °C/min and 30 °C/min) and the temperature ranged from room temperature to 1000 °C in a thermogravimetric simultaneous thermal analyzer. The results suggested that the ignition temperature and burnout temperature of MSW were lower than that of PMS, and the mass loss rate of MSW was larger especially at low temperatures. There were only two mass loss peaks in the differential thermogravimetry (DTG) curve, while three mass loss peaks were observed when the blending ratios of PMS were 30%, 50%, 70%. The value of the comprehensive combustion characteristic index of the blends indicated a good combustibility when the percentage of PMS (PPMS) in the blends was less than 30%. There existed certain interaction between the combustion process of PMS and MSW, especially at high temperature stage. Activation energy (E) value obtained by the Ozawa–Flynn–Wall (OFW) method and the Starink method were very consistent. When the mass percentage of PMS in the blends was 80%, the E average value attained the minimum

  1. Rapidly assessing the activation conditions and porosity of metal-organic frameworks using thermogravimetric analysis.

    Science.gov (United States)

    McDonald, Thomas M; Bloch, Eric D; Long, Jeffrey R

    2015-03-25

    A methodology utilizing a thermogravimetric analyzer to monitor propane uptake following incremental increases of the temperature is demonstrated as a means of rapidly identifying porous materials and determining the optimum activation conditions of metal-organic frameworks.

  2. Fluid selection and parametric analysis on condensation temperature and plant height for a thermogravimetric heat pump

    International Nuclear Information System (INIS)

    Najafi, Behzad; Obando Vega, Pedro; Guilizzoni, Manfredo; Rinaldi, Fabio; Arosio, Sergio

    2015-01-01

    the system, while the COP values remain in a relatively small range. - Highlights: • The required plant height with different working fluids for a thermogravimetric heat pump was determined. • A fluid selection diagram including COP and the required height for different fluids was presented. • Sensitivity analysis to study the effect of height increasing factor on COP was performed. • Sensitivity analysis to investigate the effect of condensation temperature on the COP was also carried out

  3. Thermogravimetric Analysis of Effects of High-Content Limstone Addition on Combustion Characteristics of Taixi Anthracite

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hong; LI Mei; SUN Min; WEI Xian-yong

    2004-01-01

    Combustion characteristics of Taixi anthracite admixed with high content of limestone addition were investigated with thermogravimetric analysis. The results show that limestone addition has a little promoting effect on the ignition of raw coals as a whole. The addition of limestone is found to significantly accelerate the combustion and burnout of raw coals. The higher the sample mass is, the more significant the effect will be. The results also show that the change of limestone proportion between 45%-80% has little effect on ignition temperatures of coal in the blended samples. Increasing limestone content lowers the temperature corresponding to the maximum weight loss. Although higher maximum mass loss rates are observed with higher limestone content, the effect is found not ascribed to changing limestone addition, but to the decrease of absolute coal mass in the sample. The change of limestone proportion has little effect on its burnout temperature. Mechanism analysis indicates that these phenomena result mainly from improved heat conduction due to limestone addition.

  4. Pyrolysis of tyre powder using microwave thermogravimetric analysis: Effect of microwave power.

    Science.gov (United States)

    Song, Zhanlong; Yang, Yaqing; Zhou, Long; Zhao, Xiqiang; Wang, Wenlong; Mao, Yanpeng; Ma, Chunyuan

    2017-02-01

    The pyrolytic characteristics of tyre powder treated under different microwave powers (300, 500, and 700 W) were studied via microwave thermogravimetric analysis. The product yields at different power levels were studied, along with comparative analysis of microwave pyrolysis and conventional pyrolysis. The feedstock underwent preheating, intense pyrolysis, and final pyrolysis in sequence. The main and secondary weight loss peaks observed during the intense pyrolysis stage were attributed to the decomposition of natural rubbers and synthetic rubbers, respectively. The total mass loss rates, bulk temperatures, and maximum temperatures were distinctively higher at higher powers. However, the maximum mass loss rate (0.005 s -1 ), the highest yields of liquid product (53%), and the minimum yields of residual solid samples (43.83%) were obtained at 500 W. Compared with conventional pyrolysis, microwave pyrolysis exhibited significantly different behaviour with faster reaction rates, which can decrease the decomposition temperatures of both natural and synthetic rubber by approximately 110 °C-140 °C.

  5. Combustion behavior and kinetics of low-lipid microalgae via thermogravimetric analysis.

    Science.gov (United States)

    Gai, Chao; Liu, Zhengang; Han, Guanghua; Peng, Nana; Fan, Aonan

    2015-04-01

    Thermogravimetric analysis and differential thermal analysis were employed to investigate combustion characteristics of two low-lipid microalgae, Chlorella pyrenoidosa (CP) and Spirulina platensis (SP) and iso-conversional Starink approach was used to calculate the kinetic parameters in the present study. The results showed that three stages of mass loss, including dehydration, devolatilization and char oxidation, were observed during combustion of both of two low-lipid microalgae. The whole weight loss of combustion of two microalgae was both shifted to higher temperature zones with increased heating rates from 10 to 40 K/min. In the 0.1-0.9 conversion range, the apparent activation energy of CP increased first from 51.96 to 79.53 kJ/mol, then decreased to 55.59 kJ/mol. Finally, it slightly increased to 67.27 kJ/mol. In the case of SP, the apparent activation energy gradually increased from 68.51 to 91.06 kJ/mol. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Pyrolysis and oxy-fuel combustion characteristics and kinetics of petrochemical wastewater sludge using thermogravimetric analysis.

    Science.gov (United States)

    Chen, Jianbiao; Mu, Lin; Cai, Jingcheng; Yao, Pikai; Song, Xigeng; Yin, Hongchao; Li, Aimin

    2015-12-01

    The pyrolysis and oxy-fuel combustion characteristics of petrochemical wastewater sludge (PS) were studied in air (O2/N2) and oxy-fuel (O2/CO2) atmospheres using non-isothermal thermogravimetric analysis (TGA). Pyrolysis experiments showed that the weight loss profiles were almost similar up to 1050K in both N2 and CO2 atmospheres, while further weight loss took place in CO2 atmosphere at higher temperatures due to char-CO2 gasification. Compared with 20%O2/80%N2, the drying and devolatilization stage of PS were delayed in 20%O2/80%CO2 due to the differences in properties of the diluting gases. In oxy-fuel combustion experiments, with O2 concentration increasing, characteristic temperatures decreased, while characteristic combustion rates and combustion performance indexes increased. Kinetic analysis of PS decomposition under various atmospheres was performed using Coats-Redfern approach. The results indicated that, with O2 concentration increasing, the activation energies of Step 1 almost kept constant, while the values of subsequent three steps increased. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Friedel's salt profiles from thermogravimetric analysis and thermodynamic modelling of Portland cement-based mortars exposed to sodium chloride solution

    DEFF Research Database (Denmark)

    Shi, Zhenguo; Geiker, Mette Rica; Lothenbach, Barbara

    2017-01-01

    Thermogravimetric analysis (TGA), powder X-ray diffraction (XRD) and thermodynamic modelling have been used to obtain Friedel's salt profiles for saturated mortar cylinders exposed to a 2.8 M NaCl solution. Comparison of the measured Friedel's salt profiles with the total chloride profiles...

  8. Pyrolysis behaviors and kinetic studies on Eucalyptus residues using thermogravimetric analysis

    International Nuclear Information System (INIS)

    Chen, Zhihua; Zhu, Quanjie; Wang, Xun; Xiao, Bo; Liu, Shiming

    2015-01-01

    Highlights: • The first study on pyrolysis characteristics and kinetic of Eucalyptus residues. • Pyrolysis process can be divided into three stages using differential DTG method. • A new modified discrete DAEM showed better than Gaussian DAEM for kinetic studies. • Variations of activation energy reveal the mechanism change during pyrolysis process. - Abstract: The pyrolysis behaviors and kinetics of Eucalyptus leaves (EL), Eucalyptus bark (EB) and Eucalyptus sawdust (ESD) were investigated by using thermogravimetric analysis (TGA) technique. Three stages for EL, EB and ESD pyrolysis have been divided using differential derivative thermogravimetric (DDTG) method and the second stage is the main pyrolysis process with approximately 86.93% (EL), 88.96% (EB) and 97.84% (ESD) weight loss percentages. Kinetic parameters of Gaussian distributed activation energy model (DAEM) for EL, EB and ESD pyrolysis are: distributed centers (E_0) of 141.15 kJ/mol (EL), 149.21 kJ/mol (EB), 175.79 kJ/mol (ESD), standard deviations (σ) of 18.35 kJ/mol (EL), 18.37 kJ/mol (EB), 14.41 kJ/mol (ESD) and pre-exponential factors (A) of 1.15E+10 s"−"1 (EL), 4.34E+10 s"−"1 (EB), 7.44E+12 s"−"1 (ESD). A new modified discrete DAEM was performed and showed excellent fits to experimental data than Gaussian DAEM. According to the modified discrete DAEM, the activation energies are in ranges of 122.67–308.64 kJ/mol, 118.72–410.80 kJ/mol and 108.39–192.93 kJ/mol for EL, EB and ESD pyrolysis, respectively. The pre-exponential factors of discrete DAEM have wide ranges of 4.84E+13–6.12E+22 s"−"1 (EL), 1.91E+12–4.51E+25 s"−"1 (EB) and 63.43–4.36E+11 s"−"1 (ESD). The variation of activation energy versus conversion reveals the mechanism change during pyrolysis process. The kinetic data would be of immense benefit to model, design and develop suitable thermo-chemical systems for the application of Eucalyptus residues.

  9. Pyrolysis kinetics investigation of Malaysian based biomass with non-isothermal thermogravimetric analysis (TGA)

    International Nuclear Information System (INIS)

    Seyed Shahabeddin Nehzati; Dayang Radiah Awang Biak; Wan Azlina Wan Abdul Karim Ghani; Mohd Amran Mohd Salleh

    2010-01-01

    Full text: Biomass is currently being used as a sustainable energy source. Otherwise the scarceness of fossil fuel sources and the demand for environmental responsibility force the industries to use biomass as an alternate source of energy. Pyrolysis is the first step of biomass conversion and well understanding of this process can develop the biomass conversion such as gasification, liquefaction, carbonization and combustion .TGA studies of Malaysian based biomass have been carried out. TGA studies provide important insight on the thermochemical behavior of specific solid waste. The results of non-isothermal thermogravimetric analysis of palm kernel shell, coconut shell and bagasse, carried out at heating rates of 10 degree Celsius/ min, 20 degree Celsius/ min and 50 degree Celsius/ min, to ramp the temperature from 30 to 1000 were analysed. The TGA studies were carried out in an inert atmosphere of nitrogen. Arrhenius parameters were estimated by 3 different models namely Kissinger model, three-pseudo component and DEAM model the estimated values and the models were compared. The results show that the three-pseudo component model has a good agreement with the experimental results, indicating that ligno celluloses components in the mixture behave in the same way as they do separately. Also it is seen that the decomposition process shifts to higher temperatures at higher heating rates as a result of the competing effects of heat and mass transfer to the material. (Author)

  10. Thermogravimetric Analysis (TGA) Profile of Modified Sba-15 at Different Amount of Alkoxy silane Group

    International Nuclear Information System (INIS)

    Norhasyimi Rahmat; Nur Fathilah Mohd Yusof; Ezani Hafiza

    2014-01-01

    This study focused on meso porous silica SBA-15 modified with alkoxy silane functional group; phenyltriethoxysilane (PTES) and vinyltriethoxysilane (VTES) using direct synthesis and post-grafting methods. By direct synthesis method, SBA-15 template by triblock copolymer (P123) and functionalized with alkoxy silane groups at different amount of loadings were co-condensed with tetraethyl orthosilicate (TEOS) under acidic conditions. As for post-grafting method, different loadings of alkoxy silane groups were added after co-condensation of TEOS with P123 template. Both synthesis methods used calcination process to remove surfactant template at 550 degree Celsius for 5 hours. The derivatized SBA-15 was characterized by thermogravimetric analysis to evaluate the profile at different loadings of alkoxy silane groups with different synthesis method. At temperature range of 300-800 degree Celsius, post-grafting method displayed the highest weight loss of phenyl and vinyl groups. However, there was no significant difference of weight loss for different amount of organo silane groups. In this study, TGA has shown to be significant characterization means to determine the effects of different method used in synthesizing modified SBA-15. It was shown that different loading of phenyl and vinyl groups did not affect the efficiency of surfactant removal. (author)

  11. Pyrolysis kinetics and thermal behavior of waste sawdust biomass using thermogravimetric analysis.

    Science.gov (United States)

    Mishra, Ranjeet Kumar; Mohanty, Kaustubha

    2018-03-01

    The present study reports pyrolysis behavior of three waste biomass using thermogravimetric analysis to determine kinetic parameters at five different heating rates. Physiochemical characterization confirmed that these biomass have the potential for fuel and energy production. Pyrolysis experiments were carried out at five different heating rates (5-25 °C min -1 ). Five model-free methods such as Kissinger-Akahira-Sunose (KAS), Ozawa-Flynn-Wall (OFW), Friedman, Coats-Redfern, and distributed activation energy (DAEM) were used to calculate the kinetic parameters. The activation energy was found to be 171.66 kJ mol -1 , 148.44 kJ mol -1 , and 171.24 kJ mol -1 from KAS model; 179.29 kJ mol -1 , 156.58 kJ mol -1 , and 179.47 kJ mol -1 from OFW model; 168.58 kJ mol -1 , 181.53 kJ mol -1 , and 184.61 kJ mol -1 from Friedman model; and 206.62 kJ mol -1 , 171.63 kJ mol -1 , and 160.45 kJ mol -1 from DAEM model for PW, SW, AN biomass respectively. The calculated kinetic parameters are in good agreement with other reported biomass. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. A Combined Raman Spectroscopic and Thermogravimetric Analysis Study on Oxidation of Coal with Different Ranks

    Directory of Open Access Journals (Sweden)

    Weiqing Zhang

    2015-01-01

    Full Text Available Raman spectroscopy and nonisothermal thermogravimetric analysis (TGA measurements have been reported for different rank coals (lignite, bituminous coal, and anthracite and the relationship between the measurements was examined. It was found that the Raman spectra parameters can be used to characterize structure changes in the different rank coals, such as the band area ratios based on the curve-fitted results. Higher ranked coal was found to have higher values of IGR/IAll and IG+GR/IAll but lower values of ID/I(G+GR, IDL/I(G+GR, IS+SL/I(G+GR, and I(GL+GL'/I(G+GR. The oxidation properties of the coal samples were characterized by the reactivity indexes Tig, T20%, and Tmax from TGA data which were found to correlate well with the band area ratios of IGR/IAll, IG+GR/IAll, and IS+SL/I(G+GR. Based on these correlations, the Raman band area ratios were found to correlate with the oxidation activity of coal providing additional structural information which can be used to understand the changes in the TGA measurements.

  13. Determination of activation energy for animal fat and crude glycerol using thermogravimetric analysis

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Crhristoph [University of Hannover, Hannover (Germany); Mortari, Daniela; Avila, Ivonete; Santos, Antonio Moreira dos; Silva, Mario Lucio Cristovam; Crnkovic, Paula Manoel [University of Sao Paulo, Sao Carlos, SP (Brazil)], e-mails: iavila@sc.usp.br, asantos@sc.usp.br, paulam@sc.usp.br

    2010-07-01

    The present study deals with the determination of the activation energy of animal fat and crude glycerol from a biodiesel production plant. The activation energies were investigated by thermogravimetric analysis in the temperature range of {delta}T = 25-600 deg C. The transient experiments were run for every sample (10 mg) at five different heating rates (2.5, 5.0, 10.0, 20.0 and 30.0 deg C/min) in atmosphere of synthetic air. It is possible to establish a direct relation between the activation energy and the ignition delay, which characterizes the combustion quality of a fuel. The activation energy could be determined as a function of the conversion degree and the temperature by the isoconversional model free kinetics. Four distinct phases were found for each sample and one of these phases was identified as low-temperature oxidation (LTO). As this region is responsible for the first vaporization of the fuel, the activation energies were determined for this special region along the whole conversion range (0 - 100 %). The following mean values could be determined: animal fat = 108.87 +- 52.28 kJ/mol, and crude glycerol = 65.37+- 13.17 kJ/mol. From these data, it was possible to conclude that animal fat is the most complex sample between the ones studied in this work (author)

  14. Oxy-fuel combustion characteristics and kinetics of microalgae Chlorella vulgaris by thermogravimetric analysis.

    Science.gov (United States)

    Chen, Chunxiang; Lu, Ziguang; Ma, Xiaoqian; Long, Jun; Peng, Yuning; Hu, Likun; Lu, Quan

    2013-09-01

    Oxy-fuel or O2/CO2 combustion technology was used to investigate the combustion of Chlorella vulgaris by thermogravimetric analysis (TGA). Oxy-fuel combustion occurs in an O2/CO2 atmosphere instead of an O2/N2 atmosphere and offers an alternative method of C. vulgaris preparation for biofuels processing. Our results show that three stages were observed during C. vulgaris combustion and the main combustion process occurred at the second stage. Compared with a 20%O2/80%N2 atmosphere, the mass loss rate at the DTG peaks (Rp) and the average reaction rate (Rv) in a 20%O2/80%CO2 atmosphere was lower, while the ignition temperature (TI) was higher. As oxygen concentration increases in an O2/CO2 atmosphere, Rp, Rv and the apparent activation energy (E) increases, while TI, the final temperature detected as mass stabilization (Tf) and the residue mass (Mr) decreases; As the heating rate (β) increases, TI, Tf and Rp increase, while Mr decreases. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  15. A Combined Raman Spectroscopic and Thermogravimetric Analysis Study on Oxidation of Coal with Different Ranks.

    Science.gov (United States)

    Zhang, Weiqing; Jiang, Shuguang; Hardacre, Christopher; Goodrich, Peter; Wang, Kai; Shao, Hao; Wu, Zhengyan

    2015-01-01

    Raman spectroscopy and nonisothermal thermogravimetric analysis (TGA) measurements have been reported for different rank coals (lignite, bituminous coal, and anthracite) and the relationship between the measurements was examined. It was found that the Raman spectra parameters can be used to characterize structure changes in the different rank coals, such as the band area ratios based on the curve-fitted results. Higher ranked coal was found to have higher values of I GR/I All and I (G + GR)/I All but lower values of I D/I (G+GR), I DL/I (G+GR), I (S + SL)/I (G+GR), and I (GL+GL')/I (G+GR). The oxidation properties of the coal samples were characterized by the reactivity indexes T ig, T 20%, and T max from TGA data which were found to correlate well with the band area ratios of I GR/I All, I (G + GR)/I All, and I (S + SL)/I (G+GR). Based on these correlations, the Raman band area ratios were found to correlate with the oxidation activity of coal providing additional structural information which can be used to understand the changes in the TGA measurements.

  16. Pyrolysis kinetics of raw and hydrothermally carbonized Karanj (Pongamia pinnata) fruit hulls via thermogravimetric analysis.

    Science.gov (United States)

    Islam, Md Azharul; Asif, M; Hameed, B H

    2015-03-01

    The pyrolysis of karanj fruit hulls (KFH) and karanj fruit hull hydrothermal carbonization (KFH-HTC) hydrochar was thermogravimetrically investigated under a nitrogen environment at 5 °C/min, 10 °C/min, and 20 °C/min. The pyrolysis decomposition of KFH biomass was faster than that of KFH-HTC hydrochar because of the high volatility and fixed carbon of KFH biomass. Weight loss percentage was also affected by the heating rates. The kinetic data were evaluated with the Kissinger-Akahira-Sunose and Flynn-Wall-Ozawa methods. The activation energy values obtained with these two methods were 61.06 and 68.53 kJ/mol for KFH biomass and 130.49 and 135.87 kJ/mol for KFH-HTC hydrochar, respectively. The analysis of kinetic process mechanisms was verified with the Coats-Redfern method. KFH-HTC hydrochar may play a potential role in transforming biomass to energy-rich feedstock for thermochemical applications because of its high heating value, high fixed carbon, and low ash and sulfur contents. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Characteristics and kinetic study on pyrolysis of five lignocellulosic biomass via thermogravimetric analysis.

    Science.gov (United States)

    Chen, Zhihua; Hu, Mian; Zhu, Xiaolei; Guo, Dabin; Liu, Shiming; Hu, Zhiquan; Xiao, Bo; Wang, Jingbo; Laghari, Mahmood

    2015-09-01

    Pyrolysis characteristics and kinetic of five lignocellulosic biomass pine wood sawdust, fern (Dicranopteris linearis) stem, wheat stalk, sugarcane bagasse and jute (Corchorus capsularis) stick were investigated using thermogravimetric analysis. The pyrolysis of five lignocellulosic biomass could be divided into three stages, which correspond to the pyrolysis of hemicellulose, cellulose and lignin, respectively. Single Gaussian activation energy distributions of each stage are 148.50-201.13 kJ/mol with standard deviations of 2.60-13.37 kJ/mol. The kinetic parameters of different stages were used as initial guess values for three-parallel-DAEM model calculation with good fitting quality and fast convergence rate. The mean activation energy ranges of hemicellulose, cellulose and lignin were 148.12-164.56 kJ/mol, 171.04-179.54 kJ/mol and 175.71-201.60 kJ/mol, with standard deviations of 3.91-9.89, 0.29-1.34 and 23.22-27.24 kJ/mol, respectively. The mass fractions of hemicellulose, cellulose and lignin in lignocellulosic biomass were respectively estimated as 0.12-0.22, 0.54-0.65 and 0.17-0.29. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Thermogravimetric analysis of rice and wheat straw catalytic combustion in air- and oxygen-enriched atmospheres

    International Nuclear Information System (INIS)

    Yu Zhaosheng; Ma Xiaoqian; Liu Ao

    2009-01-01

    By thermogravimetric analysis (TGA) study, the influences of different catalysts on the ignition and combustion of rice and wheat straw in air- and oxygen-enriched atmospheres have been investigated in this paper. Straw combustion is divided into two stages. One is the emission and combustion of volatiles and the second is the combustion of fixed carbon. The existence of catalysts in the first step enhances the emission of volatiles from the straw. The action of catalysts in the second step of straw combustion may be as a carrier of oxygen to the fixed carbon. Two parameters have been used to compare the characteristics of ignition and combustion of straw under different catalysts and in various oxygen concentrations. One is the temperature when the conversion degree combustible (CDC) of straw is 5%, the other is the CDC when the temperature is 900 deg. C. By comparing the different values of the two parameters, the different influences of the catalysts and oxygen concentration on the ignition and combustion of straw have been studied, the action of these catalysts for straw ignition and combustion in air and oxygen-enriched atmosphere is effective except the oxygen-enriched catalytic combustion of wheat straw fixed carbon

  19. Thermal Behaviour of Five Different Date Palm Residues of Algeria by Thermogravimetric Analysis

    Directory of Open Access Journals (Sweden)

    Siham AMIROU

    2013-06-01

    Full Text Available Renewable energy has become moreimportant globally especially with the current fuel andeconomic crisis. Date palm biomasses are highlypotential materials for energy resources. The factthat they are renewable and abundantly availableare amongst the attractive reasons of employingthem as the major source for renewable energy. Thepurpose of this research was to investigate thethermal behavior of date palm biomass in order toevaluate their usefulness for energy production. Inmicroparticular scale, the thermogravimetric analysis(TGA is one of the techniques used to determinethe thermal properties of five different date palmresidues that were studied: (date palm rachis (DPR,date palm trunk (DPT, leaf base (Petiole (LB,fruitstalk prunings (FP and liff (LP. The TGAtechnique consists to record the lost weight duringthe increase in temperature from 20°C until 600°Cwith a 10°C/min heating rate. The thermogramspresented a departure phase of free water (fromroom temperature to 110°C before the degradationprocess of the lignocellulosic constituents. The ligninand hemicellulose play an important role on thedegradation of lignocellulosic materials at thetemperature under 250°C. The degradation ofcellulose begins at 250°C and overlaps to that oflignin until 450°C.

  20. The research of moisture forms in the baking yeast by the thermogravimetric analysis method

    Directory of Open Access Journals (Sweden)

    S. V. Lavrov

    2016-01-01

    Full Text Available The thermogravimetry method is one of the few absolute methods of analysis, that makes it one of the most accurate methods. In this research, thermogravimetric analysis of baking yeast (Saccharomyces cerevisiae was carried out. It allowed to identify temperature zones, which correspond to dripping with various link energy, as well as to predict operating parameters of the process of dehumidification and to choose their most effective dehydration method. The studies were conducted in the laboratory of the collective use center "Control and management of energy efficient projects" of the "Voronezh state university of engineering technologies" on the simultaneous thermal analysis device STA 449 F3 model (NETZSCH, Germany. The device records the change in a substance mass and the difference of the heat flow inside the crucible containing the sample and the crucible containing the standard analyte. The analyzer's working principle is based on continuous recording of the dependence of the material mass on time or temperature and its being heated to the selected temperature program in a specified gas atmosphere. The release or absorption of heat by the sample due to phase transitions or chemical reactions is recorded simultaneously. The study was performed in the following modes: the pressure is atmospheric, the maximum temperature is 588 K, the rate of temperature change is 5 K/min. The experiments were performed in aluminum crucibles with a total weight of 12 mg. The software NETZSCH Proteus was used for processing of the obtained TG and DTG curves. The analysis of the obtained data allowed to identify periods of water dehydration and solids transformation by thermal effect on baking yeast, and to identify temperature zones, which correspond to the release of moisture with different link form and energy.

  1. Thermogravimetric analysis and kinetic study of formation of lithium titanate by solid state route

    International Nuclear Information System (INIS)

    Sonak, Sagar; Jain, Uttam; Sahu, Ashok Kumar; Kumar, Sanjay; Krishnamurthy, Nagaiyar

    2015-01-01

    The kinetics of formation of lithium titanate from the solid state reaction of lithium carbonate and titanium oxide was studied using non-isothermal thermogravimetric technique. Thermogravimetric data for the reaction of lithium carbonate and titanium oxide was obtained at various heating rates. The methods such as Flynn–Wall–Ozawa and Kissinger–Akahira–Sunose were used to estimate the kinetic parameters from the obtained thermogravimetric data. The average activation energy for the formation of lithium titanate by solid state route was found to be 243 kJ/mol K. The reaction mechanism was determined by the method given by Malek. It was found that the three dimensional diffusion model best describes the reaction kinetics. A kinetic equation describing the reaction is proposed and reaction mechanism is discussed

  2. Interactions of coal gangue and pine sawdust during combustion of their blends studied using differential thermogravimetric analysis.

    Science.gov (United States)

    Zhang, Yuanyuan; Zhang, Zhezi; Zhu, Mingming; Cheng, Fangqin; Zhang, Dongke

    2016-08-01

    The interactions between coal gangue and pine sawdust during the combustion process were studied using thermogravimetric analysis. The effect of the blending ratio, oxygen concentration and heating rate on the weight loss (TG) and differential thermogravimetric (TGA) profiles was examined. The TG and DTG curves of the blends were not additives of those of the individual materials, suggesting that interactions between coal gangue and pine sawdust had occurred during the combustion, especially in the temperature range of 400-600°C. Kinetic analysis confirmed that the combustion of coal gangue, pine sawdust and their blends was chemical reaction controlled. Further analysis revealed that the interactions between coal gangue and pine sawdust were primarily due to thermal effects rather than structural changes, with the thermal inertia of coal gangue dominating over the behaviour of the blends. The interactions decreased with decreasing the coal gangue ratio in the blend, oxygen concentration and heating rate. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Combustion characteristics of Malaysian oil palm biomass, sub-bituminous coal and their respective blends via thermogravimetric analysis (TGA).

    Science.gov (United States)

    Idris, Siti Shawalliah; Rahman, Norazah Abd; Ismail, Khudzir

    2012-11-01

    The combustion characteristics of Malaysia oil palm biomass (palm kernel shell (PKS), palm mesocarp fibre (PMF) and empty fruit bunches (EFB)), sub-bituminous coal (Mukah Balingian) and coal/biomass blends via thermogravimetric analysis (TGA) were investigated. Six weight ratios of coal/biomass blends were prepared and oxidised under dynamic conditions from temperature 25 to 1100°C at four heating rates. The thermogravimetric analysis demonstrated that the EFB and PKS evolved additional peak besides drying, devolatilisation and char oxidation steps during combustion. Ignition and burn out temperatures of blends were improved in comparison to coal. No interactions were observed between the coal and biomass during combustion. The apparent activation energy during this process was evaluated using iso-conversional model free kinetics which resulted in highest activation energy during combustion of PKS followed by PMF, EFB and MB coal. Blending oil palm biomass with coal reduces the apparent activation energy value. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Thermogravimetric analysis of silicon carbide-silicon nitride polycarbosilazane precursor during pyrolysis from ambient to 1000 C

    Science.gov (United States)

    Ledbetter, F. E., III; Daniels, J. G.; Clemons, J. M.; Hundley, N. H.; Penn, B. G.

    1984-01-01

    Thermogravimetric analysis data are presented on the unmeltable polycarbosilazane precursor of silicon carbide-silicon nitride fibers, over the room temperature-1000 C range in a nitrogen atmosphere, in order to establish the weight loss at various temperatures during the precursor's pyrolysis to the fiber material. The fibers obtained by this method are excellent candidates for use in applications where the oxidation of carbon fibers (above 400 C) renders them unsuitable.

  5. Quantitative detection of powdered activated carbon in wastewater treatment plant effluent by thermogravimetric analysis (TGA).

    Science.gov (United States)

    Krahnstöver, Therese; Plattner, Julia; Wintgens, Thomas

    2016-09-15

    For the elimination of potentially harmful micropollutants, powdered activated carbon (PAC) adsorption is applied in many wastewater treatment plants (WWTP). This holds the risk of PAC leakage into the WWTP effluent and desorption of contaminants into natural water bodies. In order to assess a potential PAC leakage, PAC concentrations below several mg/L have to be detected in the WWTP effluent. None of the methods that are used for water analysis today are able to differentiate between activated carbon and solid background matrix. Thus, a selective, quantitative and easily applicable method is still needed for the detection of PAC residues in wastewater. In the present study, a method was developed to quantitatively measure the PAC content in wastewater by using filtration and thermogravimetric analysis (TGA), which is a well-established technique for the distinction between different solid materials. For the sample filtration, quartz filters with a temperature stability up to 950 °C were used. This allowed for sensitive and well reproducible measurements, as the TGA was not affected by the presence of the filter. The sample's mass fractions were calculated by integrating the mass decrease rate obtained by TGA in specific, clearly identifiable peak areas. A two-step TGA heating method consisting of N2 and O2 atmospheres led to a good differentiation between PAC and biological background matrix, thanks to the reduction of peak overlapping. A linear correlation was found between a sample's PAC content and the corresponding peak areas under N2 and O2, the sample volume and the solid mass separated by filtration. Based on these findings, various wastewater samples from different WWTPs were then analyzed by TGA with regard to their PAC content. It was found that, compared to alternative techniques such as measurement of turbidity or total suspended solids, the newly developed TGA method allows for a quantitative and selective detection of PAC concentrations down to 0

  6. Thermogravimetric analysis-mass spectrometry (TG-MS) of selected Chinese palygorskites-Implications for structural water

    International Nuclear Information System (INIS)

    Cheng, Hongfei; Yang, Jing; Frost, Ray L.

    2011-01-01

    Four Chinese palygorskites clay minerals have been analysed by thermogravimetric analysis-mass spectrometry and X-ray diffraction. The structural water of the palygorskite dehydrates in the temperature range of 30-625 o C, as shown in the thermogravimetric analysis and mass spectrometric curves. The mass spectrometric curves combined the differential thermogravimetric curves enable the detailed determination of the main dehydration steps. The results show that the dehydration occurs in four main steps: (a) elimination of interparticle water and partial zeolitic water at below 110 o C, (b) release of the rest part of zeolitic water from the structural layer of palygorskite at about 160 o C, (c) dehydration of one part of bound water at about 340 o C and (d) loss of the rest part of bound water at around 450 o C. The temperatures of dehydration of the palygorskite minerals are found to be influenced by the geological environment and the amount and kind of impurities. The evolved gases in the decomposition process are various because of the different amounts and kind of impurities. It is also found that decarbonization takes place at around 600 o C due to the decomposition of calcite and dolomite impurities in these minerals. It is evident by the mass spectrometric curve that the water is given out from the samples and carbon dioxide originates from the impurity calcite and dolomite.

  7. Studies of the thermal properties of horn keratin by dielectric spectroscopy, thermogravimetric analysis and differential thermal analysis

    International Nuclear Information System (INIS)

    Marzec, E.; Piskunowicz, P.; Jaroszyk, F.

    2002-01-01

    The dielectric and thermal properties of horn keratin have been studied bu dielectric spectroscopy in the frequency range 10 1 -10 5 Hz, thermogravimetric analysis (TG) and different thermal analysis (DTA). Measurement of non-irradiated and g amma - irradiated keratin with doses 5, 50 kGy were performed at temperature from 22 to 260 o C. The results revealed the occurrence of phase transitions related to release of loosely bound water and bound water up to 200 o Cand the denaturation of the crystalline structure above this temperature. The influence of γ-irradiation on the thermal behaviour of keratin is significant only in the temperature range of denaturation. The decrease in the temperature of denaturation would suggest that γ-irradiation initiates main-chain degradation. (authors)

  8. Water desorption of cassava starch granules: A study based on thermogravimetric analysis of aqueous suspensions and humid powders.

    Science.gov (United States)

    Ayala Valencia, Germán; Djabourov, Madeleine; do Amaral Sobral, Paulo José

    2016-08-20

    This work reports on water desorption from cassava starch in relation with the structure and conditioning of granules in suspensions or after equilibration in desiccators. The experimental work is performed by thermogravimetric analysis with isothermal and non-isothermal protocols and interpreted to derive the activation energies and desorption frequencies according to the humidity range with no adjustable parameter. The analysis points out the different types of water interacting with the starch granules and relates the drying coefficients to their microscopic structure. The work helps clarifying contradictory and partial results from the literature. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Spectroscopic and thermogravimetric study of nickel sulfaquinoxaline complex

    International Nuclear Information System (INIS)

    Tailor, Sanjay M.; Patel, Urmila H.

    2016-01-01

    The ability of sulfaquinoxaline (4-Amino-N-2-quinoxalinylbenzenesulfonamide) to form metal complexes are investigated. The nickel complex of sulfaquinoxaline is prepared by reflux method and characterized by CHN analysis and IR spectra. The results of IR spectral data suggest that the binding of nickel atom to the sulfonamidic nitrogen are in good agreement. The thermogravimetric analysis (TGA), differential thermal analysis (DTA) and differential thermogravimetric (DTG) analysis of nickel sulfaquinoxaline are carried out from ambient temperature to 750°C in inert nitrogen atmosphere. The activation energy, enthalpy, entropy and Gibbs free energy of nickel sulfaquinoxaline complex is determined from the thermal curves using Broido method. The results are reported in this paper.

  10. Modelization of nanospace interaction involving a ferromagnetic atom: a spin polarization effect study by thermogravimetric analysis.

    Science.gov (United States)

    Santhanam, K S V; Chen, Xu; Gupta, S

    2014-04-01

    Ab initio studies of ferromagnetic atom interacting with carbon nanotubes have been reported in the literature that predict when the interaction is strong, a higher hybridization with confinement effect will result in spin polarization in the ferromagnetic atom. The spin polarization effect on the thermal oxidation to form its oxide is modeled here for the ferromagnetic atom and its alloy, as the above studies predict the 4s electrons are polarized in the atom. The four models developed here provide a pathway for distinguishing the type of interaction that exists in the real system. The extent of spin polarization in the ferromagnetic atom has been examined by varying the amount of carbon nanotubes in the composites in the thermogravimetric experiments. In this study we report the experimental results on the CoNi alloy which appears to show selective spin polarization. The products of the thermal oxidation has been analyzed by Fourier Transform Infrared Spectroscopy.

  11. Nonisothermal Thermogravimetric Analysis of Thai Lignite with High CaO Content

    Science.gov (United States)

    Pintana, Pakamon

    2013-01-01

    Thermal behaviors and combustion kinetics of Thai lignite with different SO3-free CaO contents were investigated. Nonisothermal thermogravimetric method was carried out under oxygen environment at heating rates of 10, 30, and 50°C min−1 from ambient up to 1300°C. Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods were adopted to estimate the apparent activation energy (E) for the thermal decomposition of these coals. Different thermal degradation behaviors were observed in lignites with low (14%) and high (42%) CaO content. Activation energy of the lignite combustion was found to vary with the conversion fraction. In comparison with the KAS method, higher E values were obtained by the FWO method for all conversions considered. High CaO lignite was observed to have higher activation energy than the low CaO coal. PMID:24250259

  12. Kinetic analysis of thermogravimetric data of thorium-all-cis-1,2,3,4-cyclopentanetetracarboxylic acid complex

    International Nuclear Information System (INIS)

    Ramarao, G.A.; Nair, P.K.R.; Srinivasulu, K.

    1979-01-01

    Thorium (IV) forms 1:1 complex with all-cis-1,2,3,4-cyclopentanetetracarboxylic acid (CPTA). Thermogravimetric analysis indicated that it undergoes primarily a two step decomposition of one corresponding to loss of water and another to the decomposition of the complex. Apparent activation energy, frequency factor and activation entropy were determined. Using the experimental data, the reaction order and activation energy were calculated by Freeman-Carroll method and also by Doyle method as modified by J. Zsako, by calculation of standard deviation instead of curve fitting method. (author)

  13. 硫化环氧化天然橡胶的热分析%Thermogravimetric Analysis of ENR Vulcanizate

    Institute of Scientific and Technical Information of China (English)

    张北龙; 陈美; 刘惠伦

    2001-01-01

    The thermogravimetric analysis of ENR(epoxidized natural rubber) has been carried out byTG-DTG methods at temperature rising rate of 5, 10, 15 and 20 ℃ · rmin-1. The results showed thatthe activation energy of the thermoreaction in flowing air during the course of mass loss wasn't alwayskeep rising, but declined at mass loss of 1.0%~10.0%, 20.0%~30.0% and 70. 0%~80. 0%.

  14. Theoretical (in B3LYP/6-3111++G** level), spectroscopic (FT-IR, FT-Raman) and thermogravimetric studies of gentisic acid and sodium, copper(II) and cadmium(II) gentisates.

    Science.gov (United States)

    Regulska, E; Kalinowska, M; Wojtulewski, S; Korczak, A; Sienkiewicz-Gromiuk, J; Rzączyńska, Z; Swisłocka, R; Lewandowski, W

    2014-11-11

    The DFT calculations (B3LYP method with 6-311++G(d,p) mixed with LanL2DZ for transition metals basis sets) for different conformers of 2,5-dihydroxybenzoic acid (gentisic acid), sodium 2,5-dihydroxybenzoate (gentisate) and copper(II) and cadmium(II) gentisates were done. The proposed hydrated structures of transition metal complexes were based on the results of experimental findings. The theoretical geometrical parameters and atomic charge distribution were discussed. Moreover Na, Cu(II) and Cd(II) gentisates were synthesized and the composition of obtained compounds was revealed by means of elemental and thermogravimetric analyses. The FT-IR and FT-Raman spectra of gentisic acid and gentisates were registered and the effect of metals on the electronic charge distribution of ligand was discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Thermogravimetric analysis for rapid assessment of moisture diffusivity in polydisperse powder and thin film matrices.

    Science.gov (United States)

    Thirunathan, Praveena; Arnz, Patrik; Husny, Joeska; Gianfrancesco, Alessandro; Perdana, Jimmy

    2018-03-01

    Accurate description of moisture diffusivity is key to precisely understand and predict moisture transfer behaviour in a matrix. Unfortunately, measuring moisture diffusivity is not trivial, especially at low moisture values and/or elevated temperatures. This paper presents a novel experimental procedure to accurately measure moisture diffusivity based on thermogravimetric approach. The procedure is capable to measure diffusivity even at elevated temperatures (>70°C) and low moisture values (>1%). Diffusivity was extracted from experimental data based on "regular regime approach". The approach was tailored to determine diffusivity from thin film and from poly-dispersed powdered samples. Subsequently, measured diffusivity was validated by comparing to available literature data, showing good agreement. Ability of this approach to accurately measure diffusivity at a wider range of temperatures provides better insight on temperature dependency of diffusivity. Thus, this approach can be crucial to ensure good accuracy of moisture transfer description/prediction especially when involving elevated temperatures. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Thermogravimetric and kinetic analysis of thermal decomposition characteristics of low-lipid microalgae.

    Science.gov (United States)

    Gai, Chao; Zhang, Yuanhui; Chen, Wan-Ting; Zhang, Peng; Dong, Yuping

    2013-12-01

    The thermal decomposition behavior of two microalgae, Chlorella pyrenoidosa (CP) and Spirulina platensis (SP), were investigated on a thermogravimetric analyzer under non-isothermal conditions. Iso-conversional Vyazovkin approach was used to calculate the kinetic parameters, and the universal integral method was applied to evaluate the most probable mechanisms for thermal degradation of the two feedstocks. The differential equations deduced from the models were compared with experimental data. For the range of conversion fraction investigated (20-80%), the thermal decomposition process of CP could be described by the reaction order model (F3), which can be calculated by the integral equation of G(α) = [(1 - α)(-2) - 1]/2. And the apparent activation energy was in the range of 58.85-114.5 kJ/mol. As for SP, it can be described by the reaction order model (F2), which can be calculated by the integral equation of G(α) = (1 - α)(-1) - 1, and the range of apparent activation energy was 74.35-140.1 kJ/mol. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Determination of kinetic parameters of Phlomis bovei de Noé using thermogravimetric analysis.

    Science.gov (United States)

    Yahiaoui, Meriem; Hadoun, Hocine; Toumert, Idir; Hassani, Aicha

    2015-11-01

    This paper reports the pyrolysis study of Phlomis bovei biomass by thermogravimetric experiments in order to determine the thermal degradation behavior and kinetic parameters. The weight losses were found to occur in three stages. In the DTG thermograms, an increase of the heating rate tended to delay thermal degradation processes towards higher temperatures. The average values of activation energy and pre-exponential factor calculated from Ozawa-Flynn-Wall, Kissinger-Akahira-Sunose and Kissinger methods are 134.83, 134.06, 223.31kJ/mol and 4.1610(13), 1.1810(10), 2.8110(11)/s, respectively. The three-pseudo-component method shows that the activation energy increases with increasing the heating rate for hemicellulose and cellulose while the activation energy of the lignin decreased with an increase of the heating rate. Predicted results and experimental data exhibit similar tendencies and the three pseudo-components model with n different from unity 1 is recommended as the most suitable for prediction of kinetic behavior of Phlomis bovei de Noé. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Thermogravimetric Analysis of Rice Husk and Coconut Pulp for Potential Bio fuel Production by Flash Pyrolysis

    International Nuclear Information System (INIS)

    Noorhaza Alias; Norazana Ibrahim; Mohd Kamaruddin Abdul Hamid

    2014-01-01

    The purpose of this paper is to study the characteristics and thermal degradation behavior of rice husk and coconut pulp for bio fuel production via flash pyrolysis technology. The elemental properties of the feedstock were characterized by an elemental analyzer while thermal properties were investigated using thermogravimetric analyzer (TGA). The pyrolysis processes were carried out at room temperature up to 700 degree Celsius in the presence of nitrogen gas flowing at 150 ml/ min. The investigated parameters are particle sizes and heating rates. The particle sizes varied in the range of dp 1 < 0.30 mm and 0.30= dp 2 <0.50 mm. The heating rates applied were 50 degree Celsius/ min and 80 degree Celsius/ min. It was shown smaller particle size produces 2.11-3.59 % less volatile product when pyrolyzed at 50 degree Celsius/ min compared to 80 degree Celsius/ min. Higher heating rates causes biomass degrades in a narrow temperature range by 25 degree Celsius. It also increases the maximum peak rate by 0.01 mg/ s for rice husk at dp 1 and 0.02 mg/ s at dp 2 . In case of coconut pulp, the change is not significant for dp 1 but for dp 2 a 0.02 mg/ s changes was recorded. (author)

  19. Thermogravimetric analysis of the co-pyrolysis of paper sludge and municipal solid waste

    International Nuclear Information System (INIS)

    Fang, Shiwen; Yu, Zhaosheng; Lin, Yousheng; Hu, Shanchao; Liao, Yanfen; Ma, Xiaoqian

    2015-01-01

    Highlights: • The co-pyrolysis of municipal solid waste, paper sludge and the blends was studied. • The reactivity of paper sludge could be improved by blending municipal solid waste. • The FWO and KAS methods were used to calculate activation energy. • The average activation energy was the minimum by blending 50% paper sludge. - Abstract: The pyrolysis characteristics of municipal solid waste (MSW), paper sludge (PS) and their blends were studied through a thermogravimetric simultaneous thermal analyzer from room temperature to 1000 °C. Meanwhile their kinetics were studied by Flynn–Wall–Ozawa (FWO) and Kissinger–Akahira–Sunose (KAS) methods. The mass proportions of PS in the blends were 10%, 30%, 50%, 70%, 90%, respectively and the experiments were carried out at different heating rates (30, 40 and 50 °C/min). The initial temperature of MSW was lower than that of PS and the terminated temperature was higher than PS. The comprehensive characteristic index decreased progressively along with the decrease of the MSW proportion. The values of average activation energies calculated by FWO and KAS methods were highly consistent. The average activation energy reached the minimum number, 96.7 kJ/mol by KAS and 11.56 kJ/mol by FWO, with the proportion of PS was 50%

  20. Chemometric modeling of thermogravimetric data for the compositional analysis of forest biomass.

    Science.gov (United States)

    Acquah, Gifty E; Via, Brian K; Fasina, Oladiran O; Adhikari, Sushil; Billor, Nedret; Eckhardt, Lori G

    2017-01-01

    The objective of this study was to investigated the use of chemometric modeling of thermogravimetric (TG) data as an alternative approach to estimate the chemical and proximate (i.e. volatile matter, fixed carbon and ash contents) composition of lignocellulosic biomass. Since these properties affect the conversion pathway, processing costs, yield and / or quality of products, a capability to rapidly determine these for biomass feedstock entering the process stream will be useful in the success and efficiency of bioconversion technologies. The 38-minute long methodology developed in this study enabled the simultaneous prediction of both the chemical and proximate properties of forest-derived biomass from the same TG data. Conventionally, two separate experiments had to be conducted to obtain such information. In addition, the chemometric models constructed with normalized TG data outperformed models developed via the traditional deconvolution of TG data. PLS and PCR models were especially robust in predicting the volatile matter (R2-0.92; RPD- 3.58) and lignin (R2-0.82; RPD- 2.40) contents of the biomass. The application of chemometrics to TG data also made it possible to predict some monomeric sugars in this study. Elucidation of PC loadings obtained from chemometric models also provided some insights into the thermal decomposition behavior of the chemical constituents of lignocellulosic biomass. For instance, similar loadings were noted for volatile matter and cellulose, and for fixed carbon and lignin. The findings indicate that common latent variables are shared between these chemical and thermal reactivity properties. Results from this study buttresses literature that have reported that the less thermally stable polysaccharides are responsible for the yield of volatiles whereas the more recalcitrant lignin with its higher percentage of elementary carbon contributes to the yield of fixed carbon.

  1. Chemometric modeling of thermogravimetric data for the compositional analysis of forest biomass.

    Directory of Open Access Journals (Sweden)

    Gifty E Acquah

    Full Text Available The objective of this study was to investigated the use of chemometric modeling of thermogravimetric (TG data as an alternative approach to estimate the chemical and proximate (i.e. volatile matter, fixed carbon and ash contents composition of lignocellulosic biomass. Since these properties affect the conversion pathway, processing costs, yield and / or quality of products, a capability to rapidly determine these for biomass feedstock entering the process stream will be useful in the success and efficiency of bioconversion technologies. The 38-minute long methodology developed in this study enabled the simultaneous prediction of both the chemical and proximate properties of forest-derived biomass from the same TG data. Conventionally, two separate experiments had to be conducted to obtain such information. In addition, the chemometric models constructed with normalized TG data outperformed models developed via the traditional deconvolution of TG data. PLS and PCR models were especially robust in predicting the volatile matter (R2-0.92; RPD- 3.58 and lignin (R2-0.82; RPD- 2.40 contents of the biomass. The application of chemometrics to TG data also made it possible to predict some monomeric sugars in this study. Elucidation of PC loadings obtained from chemometric models also provided some insights into the thermal decomposition behavior of the chemical constituents of lignocellulosic biomass. For instance, similar loadings were noted for volatile matter and cellulose, and for fixed carbon and lignin. The findings indicate that common latent variables are shared between these chemical and thermal reactivity properties. Results from this study buttresses literature that have reported that the less thermally stable polysaccharides are responsible for the yield of volatiles whereas the more recalcitrant lignin with its higher percentage of elementary carbon contributes to the yield of fixed carbon.

  2. Thermogravimetric analysis and kinetic study of bamboo waste treated by Echinodontium taxodii using a modified three-parallel-reactions model.

    Science.gov (United States)

    Yu, Hongbo; Liu, Fang; Ke, Ming; Zhang, Xiaoyu

    2015-06-01

    In this study, the effect of pretreatment with Echinodontium taxodii on thermal decomposition characteristics and kinetics of bamboo wastes was investigated by thermogravimetric analysis. The results showed fungal pretreatment can enhance the thermal degradation of bamboo. The negative effect of extractives in bamboo on the thermal decomposition can be decreased by the pretreatment. A modified three-parallel-reactions model based on isolated lignin was firstly proposed to study pyrolysis kinetics of bamboo lignocellulose. Kinetic analysis showed that with increasing pretreatment time fungal delignification was enhanced to transform the lignin component with high activation energy into that with low activation energy and raise the cellulose content in bamboo, making the thermal decomposition easier. These results demonstrated fungal pretreatment provided a potential way to improve thermal conversion efficiency of bamboo. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. A thermogravimetric analysis (TGA) method developed for estimating the stoichiometric ratio of solid-state {alpha}-cyclodextrin-based inclusion complexes

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Yuxiang; Wang, Jinpeng; Bashari, Mohanad; Hu, Xiuting [The State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122 (China); Feng, Tao [School of Perfume and Aroma Technology, Shanghai Institute of Technology, Shanghai 201418 (China); Xu, Xueming [The State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122 (China); Jin, Zhengyu, E-mail: jinlab2008@yahoo.com [The State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122 (China); Tian, Yaoqi, E-mail: yqtian@jiangnan.edu.cn [The State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122 (China)

    2012-08-10

    Highlights: Black-Right-Pointing-Pointer We develop a TGA method for the measurement of the stoichiometric ratio. Black-Right-Pointing-Pointer A series of formulas are deduced to calculate the stoichiometric ratio. Black-Right-Pointing-Pointer Four {alpha}-CD-based inclusion complexes were successfully prepared. Black-Right-Pointing-Pointer The developed method is applicable. - Abstract: An approach mainly based on thermogravimetric analysis (TGA) was developed to evaluate the stoichiometric ratio (SR, guest to host) of the guest-{alpha}-cyclodextrin (Guest-{alpha}-CD) inclusion complexes (4-cresol-{alpha}-CD, benzyl alcohol-{alpha}-CD, ferrocene-{alpha}-CD and decanoic acid-{alpha}-CD). The present data obtained from Fourier transform-infrared (FT-IR) spectroscopy showed that all the {alpha}-CD-based inclusion complexes were successfully prepared in a solid-state form. The stoichiometric ratios of {alpha}-CD to the relative guests (4-cresol, benzyl alcohol, ferrocene and decanoic acid) determined by the developed method were 1:1, 1:2, 2:1 and 1:2, respectively. These SR data were well demonstrated by the previously reported X-ray diffraction (XRD) method and the NMR confirmatory experiments, except the SR of decanoic acid with a larger size and longer chain was not consistent. It is, therefore, suggested that the TGA-based method is applicable to follow the stoichiometric ratio of the polycrystalline {alpha}-CD-based inclusion complexes with smaller and shorter chain guests.

  4. A thermogravimetric analysis (TGA) method developed for estimating the stoichiometric ratio of solid-state α-cyclodextrin-based inclusion complexes

    International Nuclear Information System (INIS)

    Bai, Yuxiang; Wang, Jinpeng; Bashari, Mohanad; Hu, Xiuting; Feng, Tao; Xu, Xueming; Jin, Zhengyu; Tian, Yaoqi

    2012-01-01

    Highlights: ► We develop a TGA method for the measurement of the stoichiometric ratio. ► A series of formulas are deduced to calculate the stoichiometric ratio. ► Four α-CD-based inclusion complexes were successfully prepared. ► The developed method is applicable. - Abstract: An approach mainly based on thermogravimetric analysis (TGA) was developed to evaluate the stoichiometric ratio (SR, guest to host) of the guest–α-cyclodextrin (Guest-α-CD) inclusion complexes (4-cresol-α-CD, benzyl alcohol-α-CD, ferrocene-α-CD and decanoic acid-α-CD). The present data obtained from Fourier transform-infrared (FT-IR) spectroscopy showed that all the α-CD-based inclusion complexes were successfully prepared in a solid-state form. The stoichiometric ratios of α-CD to the relative guests (4-cresol, benzyl alcohol, ferrocene and decanoic acid) determined by the developed method were 1:1, 1:2, 2:1 and 1:2, respectively. These SR data were well demonstrated by the previously reported X-ray diffraction (XRD) method and the NMR confirmatory experiments, except the SR of decanoic acid with a larger size and longer chain was not consistent. It is, therefore, suggested that the TGA-based method is applicable to follow the stoichiometric ratio of the polycrystalline α-CD-based inclusion complexes with smaller and shorter chain guests.

  5. Characterization of the Sublimation and Vapor Pressure of 2-(2-Nitrovinyl) Furan (G-0) Using Thermogravimetric Analysis: Effects of Complexation with Cyclodextrins.

    Science.gov (United States)

    Ruz, Vivian; González, Mirtha Mayra; Winant, Danny; Rodríguez, Zenaida; Van den Mooter, Guy

    2015-08-19

    In the present work, the sublimation of crystalline solid 2-(2-nitrovinyl) furan (G-0) in the temperature range of 35 to 60 °C (below the melting point of the drug) was studied using thermogravimetric analysis (TGA). The sublimated product was characterized using Fourier-transformed-infrared spectroscopy (FT-IR) and thin layer chromatography (TLC). The sublimation rate at each temperature was obtained using the slope of the linear regression model and followed apparent zero-order kinetics. The sublimation enthalpy from 35 to 60 °C was obtained from the Eyring equation. The Gückel method was used to estimate the sublimation rate and vapor pressure at 25 °C. Physical mixtures, kneaded and freeze-dried complexes were prepared with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) and sulfobutyl ether-β-cyclodextrin (SBE-β-CD) and analyzed using isothermal TGA at 50 °C. The complexation contributed to reducing the sublimation process. The best results were achieved using freeze-dried complexes with both cyclodextrins.

  6. Temperature-dependent deliquescence relative humidities and water activities using humidity controlled thermogravimetric analysis with application to malonic acid.

    Science.gov (United States)

    Beyer, Keith D; Schroeder, Jason R; Kissinger, Jared A

    2014-04-03

    We utilize a new experimental technique, humidity-controlled thermogravimetric analysis (HTGA), to determine temperature-dependent deliquescence relative humidities (DRH) and to determine the equilibrium concentration of a solution at a given temperature and relative humidity. To that end, we have investigated the malonic acid/water system determining the DRH and concentration/RH relationship in the temperature range 303-278 K. Excellent agreement is found with literature values for the DRH of malonic acid as a function of temperature and for the concentration/RH relationship at several temperatures. Thus, we extend the DRH and concentration/RH relationship to a broader temperature range and are using the HTGA experiments to investigate other organic acids.

  7. Combustion kinetics of hydrochar produced from hydrothermal carbonisation of Karanj (Pongamia pinnata) fruit hulls via thermogravimetric analysis.

    Science.gov (United States)

    Islam, Md Azharul; Kabir, G; Asif, M; Hameed, B H

    2015-10-01

    This study examined the combustion profile and kinetics of hydrochar produced from hydrothermal carbonisation (HTC) of Karanj fruit hulls (KFH). The HTC-KFH hydrochar combustion kinetics was investigated at 5, 10, and 20°C/min by thermogravimetric analysis. The kinetics model, Kissinger-Akahira-Sunose revealed the combustion kinetics parameters for the extent of conversion from 0.1 to 0.8; the activation energy varies from 114 to 67 kJ/mol respectively. The hydrochar combustion followed multi-steps kinetics; the Coats-Redfern models predicted the activation energies and pre-exponential constants for the hydrochar combustion zones. The diffusion models are the effective mechanism in the second and third zone. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Thermogravimetric analysis of atomized ferromagnetic composites with multiwalled carbon nanotubes: an unusual behavior of nickel in nanospace.

    Science.gov (United States)

    Chen, Xu; Gupta, S; Santhanam, K S V

    2014-03-01

    A spin polarization of atomized ferromagnetic atoms like cobalt or nickel in nano space results in the modification of the electron configuration in the ferromagnetic atom that changes its oxidative property. We have prepared cobalt and nickel composites with multiwalled carbon nanotubes using atomized cobalt and nickel particles, for investigating their thermal oxidative behavior by thermogravimetric analysis (TGA). The composites showed the absence of a thermal oxidation in the temperature range of ambient to the break down temperature of multiwalled carbon nanotubes at 800 degrees C. At this temperature while Co composite forms cobalt oxide, the Ni composite becomes volatile that results in the divergent behavior of the two ferromagnetic compounds with a weight gain observed in TGA for Co and a loss for Ni. The mechanisms operating in the two cases are discussed in this work.

  9. Effects of additives on the co-pyrolysis of municipal solid waste and paper sludge by using thermogravimetric analysis.

    Science.gov (United States)

    Fang, Shiwen; Yu, Zhaosheng; Lin, Yan; Lin, Yousheng; Fan, Yunlong; Liao, Yanfen; Ma, Xiaoqian

    2016-06-01

    By using thermogravimetric analysis (TGA), the effects of different additives (MgO, Al2O3 and ZnO) on the pyrolysis characteristics and activation energy of municipal solid waste (MSW), paper sludge (PS) and their blends in N2 atmosphere had been investigated in this study. The experiments resulted that these additives were effective in reducing the initial temperature and activation energy. However, not all the additives were beneficial to reduce the residue mass and enhance the index D. For the different ratios of MSW and PS, the same additive even had the different influences. The catalytic effects of additives were not obvious and the pyrolysis became difficult with the increase of the proportion of PS. Based on all the contrast of the pyrolysis characteristics, MgO was the best additive and 70M30P was the best ratio, respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. New sample carrier systems for thermogravimetric analysis under forced flow conditions and their influence on microkinetic results.

    Science.gov (United States)

    Seibel, C; Fieback, T M

    2015-09-01

    For thermogravimetric analysis, it has been shown that, depending on the type of sample container, different kinetic results could be obtained despite regarding the same reaction under constant conditions. This is due to limiting macrokinetic effects which are strongly dependant on the type of sample carrying system. This prompted the need for sample containers which deliver results minimally limited by diffusive mass transport. In this way, two container systems were developed, both characterized by a forced flow stream through a solid, porous bed: one from bottom to top (counter-current flow) and one from top to bottom (co-current flow). Optical test measurements were performed, the results indicating that reaction proceedings are almost fully independent of the geometrical shape of the sample containers. The Boudouard reaction was investigated with a standard crucible and the new developed systems; the reaction rates determined differed significantly, up to a factor of 6.2 at 1373 K.

  11. Determination of kinetic parameters in the pyrolysis operation and thermal behavior of Prosopis juliflora using thermogravimetric analysis.

    Science.gov (United States)

    Chandrasekaran, Arunkumar; Ramachandran, Sethumadhavan; Subbiah, Senthilmurugan

    2017-06-01

    This paper deals with the pyrolysis of Prosopis juliflora fuelwood using thermogravimetric analysis to determine the kinetic parameters at six different heating rates of 2, 5, 10, 15, 20 and 25°C/min. The activation energy of pyrolysis was calculated using different methods, namely Kissinger, Kissinger-Akahira-Sunose, Ozawa-Flynn-Wall and Friedman model and corresponding calculated activation energy were found to be 164.6, 204, 203.2, and 219.3kJ/mol, respectively for each method. The three-pseudo component model was applied to calculate the following three kinetic parameters: activation energy, pre-exponential factor and order of reaction. The experimental results were validated with model prediction for all the six heating rates. The three-pseudo component model is able to predict experimental results much accurately while considering variable order reaction model (n≠1). Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Determination of the surface density of polyethylene glycol on gold nanoparticles by use of microscale thermogravimetric analysis.

    Science.gov (United States)

    Sebby, K B; Mansfield, E

    2015-04-01

    The widespread integration of nanoparticle technologies into biomedicine will depend on the ability to repeatedly create particles with well-defined properties and predictable behaviors. For this to happen, fast, reliable, inexpensive, and widely available techniques to characterize nanomaterials are needed. Characterization of the surface molecules is particularly important since the surface, including the surface molecule density, plays a dominant role in determining how nanoparticles interact with their surroundings. Here, 10 and 30 nm gold nanoparticle NIST Standard Reference Materials were functionalized with fluorescently labeled polyethylene glycol (PEG) with either thiolate or lipoic acid anchoring groups to evaluate analytical techniques for determining surface coverage. The coating of the nanoparticles was confirmed with dynamic light scattering, microscale thermogravimetric analysis (μ-TGA), and ultraviolet-visible (UV-vis) spectroscopy. A UV-vis method for determining gold nanoparticle concentrations that takes into account spectral broadening upon functionalization was developed. The amount of bound PEG was quantified with μ-TGA, a technique analogous to thermogravimetric analysis that uses quartz crystal microbalances, and fluorescence spectroscopy of displaced ligands. It is shown that μ-TGA is a convenient technique for the quantification of ligands bound to inorganic particles while sacrificing a minimal amount of sample, and the treatment of the functionalized nanoparticle dispersions with dithiothreitol may be insufficient to achieve complete displacement of the surface ligands for quantification by fluorescence measurements. The μ-TGA and fluorescence results were used to determine ligand footprint sizes-average areas occupied by each ligand on the particles' surface. The lipoic acid bound ligands had footprint sizes of 0.21 and 0.25 nm(2) on 10 and 30 nm particles, respectively while the thiolate ligands had footprint sizes of 0.085 and 0

  13. A comprehensive evaluation of water uptake on atmospherically relevant mineral surfaces: DRIFT spectroscopy, thermogravimetric analysis and aerosol growth measurements

    Directory of Open Access Journals (Sweden)

    R. J. Gustafsson

    2005-01-01

    Full Text Available The hygroscopicity of mineral aerosol samples has been examined by three independent methods: diffuse reflectance infrared Fourier transform spectroscopy, thermogravimetric analysis and differential mobility analysis. All three methods allow an evaluation of the water coverage of two samples, CaCO3 and Arizona Test dust, as a function of relative humidity. For the first time, a correlation between absolute gravimetric measurements and the other two (indirect methods has been established. Water uptake isotherms were reliably determined for both solids which at 298 K and 80% relative humidity exhibited similar coverages of ~4 monolayers. However, the behaviour at low relative humidity was markedly different in the two cases, with Arizona Test Dust showing a substantially higher affinity for water in the contact layer. This is understandable in terms of the chemical composition of these two materials. The mobility analysis results are in good accord with field observations and with our own spectroscopic and gravimetric measurements. These findings are of value for an understanding of atmospheric chemical processes.

  14. Effect of anaerobic digestion on sequential pyrolysis kinetics of organic solid wastes using thermogravimetric analysis and distributed activation energy model.

    Science.gov (United States)

    Li, Xiaowei; Mei, Qingqing; Dai, Xiaohu; Ding, Guoji

    2017-03-01

    Thermogravimetric analysis, Gaussian-fit-peak model (GFPM), and distributed activation energy model (DAEM) were firstly used to explore the effect of anaerobic digestion on sequential pyrolysis kinetic of four organic solid wastes (OSW). Results showed that the OSW weight loss mainly occurred in the second pyrolysis stage relating to organic matter decomposition. Compared with raw substrate, the weight loss of corresponding digestate was lower in the range of 180-550°C, but was higher in 550-900°C. GFPM analysis revealed that organic components volatized at peak temperatures of 188-263, 373-401 and 420-462°C had a faster degradation rate than those at 274-327°C during anaerobic digestion. DAEM analysis showed that anaerobic digestion had discrepant effects on activation energy for four OSW pyrolysis, possibly because of their different organic composition. It requires further investigation for the special organic matter, i.e., protein-like and carbohydrate-like groups, to confirm the assumption. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Thermogravimetric and Pyrolysis-Capillary Gas Chromatography-Mass Spectrometric Analysis of Pinus Halepensis Mill. Wood

    International Nuclear Information System (INIS)

    Hafsi, S.; Benbouzid, M.; Zimny, T.

    2005-01-01

    The analytical methods TG and Py-capillary-GC-MS were used to study the thermal degradation of Pinus Halepensis Mill. wood. The TG analysis in air and in nitrogen showed that the percentage content of char and ash were, 23.1% and 7.7% respectively. TG and DTG analysis proved that the evolution of organic degradation products occurs mainly between 215C and 380C and has its maximum evolution rate at 360C in nitrogen and 347C in air. Py-capillary-GC-MS analysis of the pyrolysis at 400C identified the presence of valuable chemicals such aliphatic and aromatic hydrocarbons, phenols, aldehydes, esters and saturated and unsaturated long chain fatty acids. (author)

  16. Thermogravimetric analysis of the behavior of sub-bituminous coal and cellulosic ethanol residue during co-combustion.

    Science.gov (United States)

    Buratti, C; Barbanera, M; Bartocci, P; Fantozzi, F

    2015-06-01

    The influence of the addition of cellulosic ethanol residue (CER) on the combustion of Indonesian sub-bituminous coal was analyzed by non isothermal thermo-gravimetric analysis (TGA). The effect of blends ratio (5%, 10%, 15% and 20%), interaction mechanism, and heating rate (5°C/min, 10°C/min, 15°C/min, 20°C/min) on the combustion process was studied. The results show that the increase of the blending ratio allows to achieve the increase of the combustibility index from 7.49E-08 to 5.26E-07 at the blending ratio of 20%. Two types of non-isothermal kinetic analysis methods (Ozawa-Flynn-Wall and Vyazovkin) were also applied. Results indicate that the activation energy of the blends decreases with increasing the conversion rate. In particular, the blending ratio of 20% confirms to have the better combustion performance, with the average value of the activation energy equal to 41.10 kJ/mol obtained by Ozawa-Flynn-Wall model and 31.17 kJ/mol obtained by Vyazovkin model. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Thermal decomposition and kinetics of coal and fermented cornstalk using thermogravimetric analysis.

    Science.gov (United States)

    He, Yuyuan; Chang, Chun; Li, Pan; Han, Xiuli; Li, Hongliang; Fang, Shuqi; Chen, Junying; Ma, Xiaojian

    2018-07-01

    The thermal behavior and kinetics of Yiluo coal (YC) and the residues of fermented cornstalk (FC) were investigated in this study. The Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) methods were used for the kinetic analysis of the pyrolysis process. The results showed that the activation energy (E α ) was increased with the increase of the thermal conversion rate (α), and the average values of E α of YC, FC and the blend (m YC /m FC  = 6/4) were 304.26, 224.94 and 233.46 kJ/mol, respectively. The order reaction model function for the blend was also developed by the master-plots method. By comparing the E a and the enthalpy, it was found that the blend was favored to format activated complex due to the lower potential energy barrier. Meanwhile, the average value of Gibbs free energy of the blend was 169.83 kJ/mol, and the changes of entropies indicated that the pyrolysis process was evolved from ordered-state to disordered-state. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Pyrolysis kinetics and thermodynamic parameters of castor (Ricinus communis) residue using thermogravimetric analysis.

    Science.gov (United States)

    Kaur, Ravneet; Gera, Poonam; Jha, Mithilesh Kumar; Bhaskar, Thallada

    2018-02-01

    Castor plant is a fast-growing, perennial shrub from Euphorbiaceae family. More than 50% of the residue is generated from its stems and leaves. The main aim of this work is to study the pyrolytic characteristics, kinetics and thermodynamic properties of castor residue. The TGA experiments were carried out from room temperature to 900 °C under an inert atmosphere at different heating rates of 5, 10, 15, 20, 30 and 40 °C/min. The kinetic analysis was carried using different models namely Kissinger, Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS). The average E ɑ calculated by FWO and KAS methods were 167.10 and 165.86 kJ/mole respectively. Gibbs free energy varied from 150.62-154.33 to 150.59-154.65 kJ/mol for FWO and KAS respectively. The HHV of castor residue was 14.43 MJ/kg, considered as potential feedstock for bio-energy production. Kinetic and thermodynamic results will be useful input for the design of pyrolytic process using castor residue as feedstock. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Biological CO2 fixation using Chlorella vulgaris and its thermal characteristics through thermogravimetric analysis.

    Science.gov (United States)

    Razzak, Shaikh A; Ali, Saad Aldin M; Hossain, Mohammad M; Mouanda, Alexis Nzila

    2016-11-01

    The present research is focused on cultivation of microalgae strain Chlorella vulgaris for bio-fixation of CO2 coupled with biomass production. In this regard, a single semi-batch vertical tubular photobioreactor and four similar photobioreactors in series have been employed. The concentration of CO2 in the feed stream was varied from 2 to 12 % (v/v) by adjusting CO2 to air ratio. The amount of CO2 capture and algae growth were monitored by measuring decrease of CO2 concentration in the gas phase, microalgal cell density, and algal biomass production rate. The results show that 4 % CO2 gives maximum amount of biomass (0.9 g L(-1)) and productivity (0.118 g L(-1) day(-1)) of C. vulgaris in a single reactor. In series reactors, average productivity per reactor found to be 0.078 g L(-1) day(-1). The maximum CO2 uptake for single reactor also found with 4 % CO2, and it is around 0.2 g L(-1) day(-1). In series reactors, average CO2 uptake is 0.13 g L(-1) day(-1) per reactor. TOC analysis shows that the carbon content of the produced biomass is around 40.67 % of total weight. The thermochemical characteristics of the cultivated C. vulgaris samples were analyzed in the presence of air. All samples burn above 200 °C and the combustion rate become faster at around 600 °C. Almost 98 wt% of the produced biomass is combustible in this range.

  20. Investigation of thermodynamic parameters in the pyrolysis conversion of biomass and manure to biochars using thermogravimetric analysis.

    Science.gov (United States)

    Xu, Yiliang; Chen, Baoliang

    2013-10-01

    The thermodynamic parameters of the conversion of two companion pair materials, i.e., rice straw vs dairy manure, and rice bran vs chicken manure, to biochars were characterized by thermogravimetric analysis. The overall changes of activation energy (Ea) were well described by the Flynn-Wall method. The Ea values increased steeply from about 120 to 180 kJ/mol at the mass conversion (α) at 0.2-0.4, followed by a relatively steady change at 0.40.65. The higher contents of minerals in manures resulted in the larger Ea. The individual conversion of hemicellulose, cellulose and lignin in the feedstocks was identified and their thermodynamic parameters (ΔH°, ΔG° and ΔS°) were calculated. The yields of biochars calculated from TG curve were compared with the determined yields of biochars using muffle pyrolysis. Along with Fourier transform infrared spectra data, the distinct decompositions of biomasses and manures were evaluated. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Study of Surface Wettability Change of Unconsolidated Sand Using Diffuse Reflectance Infrared Fourier Transform Spectroscopy and Thermogravimetric Analysis.

    Science.gov (United States)

    Gómora-Herrera, Diana; Navarrete Bolaños, Juan; Lijanova, Irina V; Olivares-Xometl, Octavio; Likhanova, Natalya V

    2018-04-01

    The effects exerted by the adsorption of vapors of a non-polar compound (deuterated benzene) and a polar compound (water) on the surface of Ottawa sand and a sample of reservoir sand (Channel), which was previously impregnated with silicon oil or two kinds of surfactants, (2-hydroxyethyl) trimethylammonium oleate (HETAO) and (2-hydroxyethyl)trimethylammonium azelate (HETAA), were studied by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and thermogravimetric analysis (TGA). The surface chemistry of the sandstone rocks was elucidated by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX). Terminal surface groups such as hydroxyls can strongly adsorb molecules that interact with these surface groups (surfactants), resulting in a wettability change. The wettability change effect suffered by the surface after treating it with surfactants was possible to be detected by the DRIFTS technique, wherein it was observed that the surface became more hydrophobic after being treated with silicon oil and HETAO; the surface became more hydrophilic after treating it with HETAA.

  2. Investigation on the co-combustion of low calorific oil shale and its semi-coke by using thermogravimetric analysis

    International Nuclear Information System (INIS)

    Yang, Yu; Lu, Xiaofeng; Wang, Quanhai

    2017-01-01

    Highlights: • The co-combustion characteristic parameters were studied. • The co-combustion of oil shale and semi-coke could be expressed roughly by the addition of individual components. • Activation energy was calculated by Coats-Redfern, distributed activation energy model and Flynn-Wall-Ozawa methods. - Abstract: In the present work, thermogravimetric analysis was employed to investigate co-combustion behaviors of Fushun low calorific oil shale and its semi-coke. The synergy effect was estimated by using the interaction coefficient and the relative error of mean square root. In addition, activation energy was also calculated by means of Coats-Redfern, distributed activation energy model and Flynn-Wall-Ozawa methods. Results indicated that with the increase of oil shale mass fraction and oxygen concentration, combustion characteristics of the samples were improved. And some little interaction did occur during the co-combustion process, but it was relatively slight. Consequently, the co-combustion of oil shale and semi-coke still could be expressed roughly by the addition of individual components of the mixtures. Furthermore, activation energy of the samples decreased slowly at the initial stage attributed to the minerals’ catalytic effects, and in the final stage, it jumped to a high value, suggesting that the burnout of the samples was difficult. Besides, the mix proportion of oil shale which was added to stabilize the combustion in the circulating fluidized bed was also theoretically calculated.

  3. Understanding of thermo-gravimetric analysis to calculate number of addends in multifunctional hemi-ortho ester derivatives of fullerenol

    International Nuclear Information System (INIS)

    Singh, Rachana; Goswami, Thakohari

    2011-01-01

    Test results for the applicability of existing thermo-gravimetric analysis (TGA) technique to ascertain average number of exohedral chemical attachment in a new class of fullerene dyads consisting of multiple hemi-ortho esters onto fullerenol is presented. Although the method is nicely applicable for higher fullerenol, but homogeneous phase products calculate lower number of addends, whereas, the hetero phase products indicate higher value. Lower value is attributed to either overlapping of thermal events or substituents effects and higher value is the contribution of tetra butyl ammonium hydroxide (TBAH) impurity used as phase transfer catalyst (PTC) in heterogeneous phase reactions. Presence of TBAH impurity is recognized through thermo-gravimetry mass spectrometry (TG-MS) measurement. Appropriate modification of test method to arrive at accurate and precise values of x (total mass contribution due to addends only) and y (total mass contribution due to fullerene plus char yield) are also reported. Successful use of two more different techniques, viz., electron-spray ionization mass spectrometry (ESI-MS) and X-ray photoelectron spectroscopy (XPS), supplement above results. Influences of fullerene and different substituents on thermal behavior of dyads are assessed.

  4. Biomass pyrolysis and combustion integral and differential reaction heats with temperatures using thermogravimetric analysis/differential scanning calorimetry.

    Science.gov (United States)

    Shen, Jiacheng; Igathinathane, C; Yu, Manlu; Pothula, Anand Kumar

    2015-06-01

    Integral reaction heats of switchgrass, big bluestem, and corn stalks were determined using thermogravimetric analysis/differential scanning calorimetry (TGA/DSC). Iso-conversion differential reaction heats using TGA/DSC pyrolysis and combustion of biomass were not available, despite reports available on heats required and released. A concept of iso-conversion differential reaction heats was used to determine the differential reaction heats of each thermal characteristics segment of these materials. Results showed that the integral reaction heats were endothermic from 30 to 700°C for pyrolysis of switchgrass and big bluestem, but they were exothermic for corn stalks prior to 587°C. However, the integral reaction heats for combustion of the materials followed an endothermic to exothermic transition. The differential reaction heats of switchgrass pyrolysis were predominantly endothermic in the fraction of mass loss (0.0536-0.975), and were exothermic for corn stalks (0.0885-0.850) and big bluestem (0.736-0.919). Study results provided better insight into biomass thermal mechanism. Published by Elsevier Ltd.

  5. Pyrolysis characteristics and kinetics of microalgae via thermogravimetric analysis (TGA): A state-of-the-art review.

    Science.gov (United States)

    Bach, Quang-Vu; Chen, Wei-Hsin

    2017-12-01

    Pyrolysis is a promising route for biofuels production from microalgae at moderate temperatures (400-600°C) in an inert atmosphere. Depending on the operating conditions, pyrolysis can produce biochar and/or bio-oil. In practice, knowledge for thermal decomposition characteristics and kinetics of microalgae during pyrolysis is essential for pyrolyzer design and pyrolysis optimization. Recently, the pyrolysis kinetics of microalgae has become a crucial topic and received increasing interest from researchers. Thermogravimetric analysis (TGA) has been employed as a proven technique for studying microalgae pyrolysis in a kinetic control regime. In addition, a number of kinetic models have been applied to process the TGA data for kinetic evaluation and parameters estimation. This paper aims to provide a state-of-the art review on recent research activities in pyrolysis characteristics and kinetics of various microalgae. Common kinetic models predicting the thermal degradation of microalgae are examined and their pros and cons are illustrated. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Thermogravimetric Analysis of Textile Dyeing Sludge (TDS) in N₂/CO₂/O₂ Atmospheres and its Combustion Model with Coal.

    Science.gov (United States)

    Zhuo, Zhongxu; Liu, Jingyong; Sun, Shuiyu; Kuo, Jiahong; Sun, Jian; Chang, Ken-Lin; Fu, Jiewen

    2018-01-01

      The combustion characteristics of textile dyeing sludge (TDS) in N2/O2, CO2/O2, and N2/CO2 atmospheres, and blends of TDS with coal were analyzed using TGA (thermogravimetric analysis). Results showed that the replacement of N2 by CO2 resulted in negative effects on the combustion and pyrolysis of TDS. Comparing N2/O2 and CO2/O2 atmospheres, combustion of TDS was easier in a N2/O2 atmosphere, but the residual mass after TDS pyrolysis in pure CO2 was less than that in N2 by approximately 4.51%. When the proportion of TDS was 30-50% in the blends of coal with TDS, a synergistic interaction clearly occurred, and it significantly promoted combustion. In considering different combustion parameters, the optimal proportion of TDS may be between 20-30%. The activation energy Ea value decreased from 155.6 kJ/mol to 53.35 kJ/mol with an increasing TDS proportion from 0% to 50%, and it rapidly decreased when the TDS proportion was below 20%.

  7. Thermal degradation of Shredded Oil Palm Empty Fruit Bunches (SOPEFB) embedded with Cobalt catalyst by Thermogravimetric Analysis (TGA)

    Science.gov (United States)

    Alias, R.; Hamid, N. H.; Jaapar, J.; Musa, M.; Alwi, H.; Halim, K. H. Ku

    2018-03-01

    Thermal behavior and decomposition kinetics of shredded oil palm empty fruit bunches (SOPEFB) were investigated in this study by using thermogravimetric analysis (TGA). The SOPEFB were analyzed under conditions of temperature 30 °C to 900 °C with nitrogen gas flow at 50 ml/min. The SOPEFB were embedded with cobalt (II) nitrate solution with concentration 5%, 10%, 15% and 20%. The TG/DTG curves shows the degradation behavior of SOPEFB following with char production for each heating rate and each concentration of cobalt catalyst. Thermal degradation occurred in three phases, water drying phase, decomposition of hemicellulose and cellulose phase, and lignin decomposition phase. The kinetic equation with relevant parameters described the activation energy required for thermal degradation at the temperature regions of 200 °C to 350 °C. Activation energy (E) for different heating rate with SOPEFB embedded with different concentration of cobalt catalyst showing that the lowest E required was at SOPEFB with 20% concentration of cobalt catalyst..

  8. Consequences of poly(vinyl chloride) presence on the thermochemical process of lignocellulosic biomass in CO₂ by thermogravimetric analysis.

    Science.gov (United States)

    He, Yao; Ma, Xiaoqian; Zeng, Guangbo

    2015-02-01

    The thermochemical processes of lignocellulosic biomass and its mixtures with poly(vinyl chloride) (PVC) fractions were investigated by thermogravimetric analysis in CO2 atmosphere. Superposition property was assumed to examine whether and/or to what extent interactions occurred during the mixture decomposition. Results showed that interactions existed, of which the intensities changed with reaction stage, heating rate and PVC quantity, and they actively behaved toward the decomposition in most cases. With PVC presence, lignocellulosic biomass turned from three-stage to four-stage decomposition process where the reactions occurred at lower temperatures with heightened intensity, especially in the first stage. The measured activation energies calculated by Ozawa-Flynn-Wall and Vyazovkin methods were of minor difference <5 kJ/mol, and comparing them between materials in each stage confirmed the results of interaction impact. This work provides a theoretical basis bringing about the possibilities of recycling CO2 into a reaction medium of thermo-treatment of lignocellulosic material with PVC contaminants. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Measurement of the oxidation of spent fuel between 140/degree/ and 225/degree/C by thermogravimetric analysis

    International Nuclear Information System (INIS)

    Woodley, R.E.; Einziger, R.E.; Buchanan, H.C.

    1988-09-01

    A series of PWR spent fuel samples from Turkey Point Unit 3 have been oxidized at temperatures between 140/degree/ and 225/degree/C in air atmospheres with dew points between 14.5/degree/ and /minus/70/degree/C, using a thermogravimetric analysis system (TGA). Tests lasted between 400 and 2100 hours. At the conclusion of a test, the atmosphere was sampled to determine the release of fission gas during testing, and the fuel samples were analyzed for microstructural changes. It appears that the mechanism for oxidation of spent fuel to U/sub 3/O/sub 7/ takes place in two steps that occur somewhat simultaneously. Oxygen migrates along the grain boundaries, which are oxidized and enlarged. The grains oxidize by the inward progression of a layer of U/sub 4/O/sub 9/ saturated with oxygen. A simplified model of the mechanism, which considers oxygen diffusion through the product layer as the rate-controlling step, yields an activation energy of 27 /plus minus/ 4 kcal/mol. Moisture, between dew points of /minus/70/degree/ to +14.5/degree/C, i.e., water vapor partial pressures varying over four orders of magnitude, had no significant effect on the oxidation rate. 34 refs., 12 figs., 6 tabs

  10. Investigation on the co-combustion of oil shale and municipal solid waste by using thermogravimetric analysis

    International Nuclear Information System (INIS)

    Fan, Yunlong; Yu, Zhaosheng; Fang, Shiwen; Lin, Yan; Lin, Yousheng; Liao, Yanfen; Ma, Xiaoqian

    2016-01-01

    Highlights: • Co-combustion of oil shale with municipal solid waste created significant changes. • Blending with municipal solid wastes could improve the combustion performance. • 10–30% of oil shale in the blends could be determined as the optimum ratio range. • Activation energy were calculated by the conversion rate and different proportion. - Abstract: The aim of this study is trying to reveal the thermal characteristics and kinetics of oil shale, municipal solid waste and their blends in the combustion process which are needed for efficient utilization. The combustion experiment is carried out in a thermogravimetric simultaneous thermal analyzer, where the temperature ranged from 110 °C to 900 °C at three different heating rates as 10 °C/min, 20 °C/min and 30 °C/min. Their kinetics were studied by Ozawa–Flynn–Wall and Friedmen methods. According to the data analysis, combustion characteristic index increased progressively with the increase of the proportion of municipal solid waste. And it’s suggested that there was certain interaction in the combustion process of oil shale and municipal solid waste. The average activation energy of the blends reached the minimum value, 177.7927 kJ/mol by Ozawa–Flynn–Wall method and 167.4234 kJ/mol by Friedmen method, when the proportion of MSW was 70%.

  11. Thermogravimetric Analysis of Modified Hematite by Methane (CH{sub 4}) for Chemical-Looping Combustion: A Global Kinetics Mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Monazam, Esmail R; Breault, Ronald W; Siriwardane, Ranjani; Miller, Duane D

    2013-10-01

    Iron oxide (Fe{sub 2}O{sub 3}) or in its natural form (hematite) is a potential material to capture CO{sub 2} through the chemical-looping combustion (CLC) process. It is known that magnesium (Mg) is an effective methyl cleaving catalyst and as such it has been combined with hematite to assess any possible enhancement to the kinetic rate for the reduction of Fe{sub 2}O{sub 3} with methane. Therefore, in order to evaluate its effectiveness as a hematite additive, the behaviors of Mg-modified hematite samples (hematite –5% Mg(OH){sub 2}) have been analyzed with regard to assessing any enhancement to the kinetic rate process. The Mg-modified hematite was prepared by hydrothermal synthesis. The reactivity experiments were conducted in a thermogravimetric analyzer (TGA) using continuous stream of CH{sub 4} (5, 10, and 20%) at temperatures ranging from 700 to 825 {degrees}C over ten reduction cycles. The mass spectroscopy analysis of product gas indicated the presence of CO{sub 2}, H{sub 2}O, H{sub 2} and CO in the gaseous product. The kinetic data at reduction step obtained by isothermal experiments could be well fitted by two parallel rate equations. The modified hematite samples showed higher reactivity as compared to unmodified hematite samples during reduction at all investigated temperatures.

  12. Comparative evaluation of thermal oxidative decomposition for oil-plant residues via thermogravimetric analysis: Thermal conversion characteristics, kinetics, and thermodynamics.

    Science.gov (United States)

    Chen, Jianbiao; Wang, Yanhong; Lang, Xuemei; Ren, Xiu'e; Fan, Shuanshi

    2017-11-01

    Thermal oxidative decomposition characteristics, kinetics, and thermodynamics of rape straw (RS), rapeseed meal (RM), camellia seed shell (CS), and camellia seed meal (CM) were evaluated via thermogravimetric analysis (TGA). TG-DTG-DSC curves demonstrated that the combustion of oil-plant residues proceeded in three stages, including dehydration, release and combustion of organic volatiles, and chars oxidation. As revealed by combustion characteristic parameters, the ignition, burnout, and comprehensive combustion performance of residues were quite distinct from each other, and were improved by increasing heating rate. The kinetic parameters were determined by Coats-Redfern approach. The results showed that the most possible combustion mechanisms were order reaction models. The existence of kinetic compensation effect was clearly observed. The thermodynamic parameters (ΔH, ΔG, ΔS) at peak temperatures were calculated through the activated complex theory. With the combustion proceeding, the variation trends of ΔH, ΔG, and ΔS for RS (RM) similar to those for CS (CM). Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Quantitative gas analysis with FT-IR

    DEFF Research Database (Denmark)

    Bak, J.; Larsen, A.

    1995-01-01

    Calibration spectra of CO in the 2.38-5100 ppm concentration range (22 spectra) have been measured with a spectral resolution of 4 cm(-1), in the mid-IR (2186-2001 cm(-1)) region, with a Fourier transform infrared (FT-IR) instrument. The multivariate calibration method partial least-squares (PLS1...

  14. Comparative study on the pyrolysis behaviour and kinetics of two macroalgae biomass (Gracilaria changii and Gelidium pusillum) by thermogravimetric analysis

    Science.gov (United States)

    Roslee, A. N.; Munajat, N. F.

    2017-10-01

    Macroalgae are often referred as seaweed and could be significant biomass resource for the production of numerous energy carriers including biofuels. In this study, the chemical composition of Gracilaria changii (G. changii) and Gelidium pusillum (G. pusillum) were determined through proximate and ultimate analysis and the thermal degradation behaviour of G. changii and G. pusillum were investigated via thermogravimetric analysis (TGA) in determining the important main composition to be considered as biomass fuels. It has found the pyrolysis of G. changii and G. pusillum consists of three stages and stage II is the main decomposition stage with major mass loss of around 52.16% and 44.42%, respectively. The TGA data were then used for determination of kinetic parameters of the pyrolysis process using three model-free methods: Kissinger, Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO). The apparent activation energy calculated by using Kissinger method for G. changii was lower than G. Pusillum, i.e.173.12 kJ/mol and 193.22 kJ/mol, respectively. The activation energies calculated from KAS and FWO methods were increased with increasing the pyrolysis conversion with average activation energies of 172.32 kJ/mol and 181.19 kJ/mol for G. changii while for G. pusillum (177.42 kJ/mol and 187.4 kJ/mol). G. pusillum has lower and wider distribution of activation energy and revealed that the pyrolysis process for G. changii was easier than G. pusillum. These data provide information for further application for designing and modelling in thermochemical conversion system of macroalgae biomass.

  15. A thermogravimetric analysis (TGA) method to determine the catalytic conversion of cellulose from carbon-supported hydrogenolysis process

    International Nuclear Information System (INIS)

    Leal, Glauco F.; Ramos, Luiz A.; Barrett, Dean H.; Curvelo, Antonio Aprígio S.; Rodella, Cristiane B.

    2015-01-01

    Graphical abstract: - Highlights: • A new method to determine the catalytic conversion of cellulose using TGA has been developed. • TGA is able to differentiate between carbon from cellulose and carbon from the catalyst. • Building an analytical curve from TGA results enables the accurate determination of cellulose conversion. - Abstract: The ability to determine the quantity of solid reactant that has been transformed after a catalytic reaction is fundamental in accurately defining the conversion of the catalyst. This quantity is also central when investigating the recyclability of a solid catalyst as well as process control in an industrial catalytic application. However, when using carbon-supported catalysts for the conversion of cellulose this value is difficult to obtain using only a gravimetric method. The difficulty lies in weighing errors caused by loss of the solid mixture (catalyst and non-converted cellulose) after the reaction and/or moisture adsorption by the substrate. These errors are then propagated into the conversion calculation giving erroneous results. Thus, a quantitative method using thermogravimetric analysis (TGA) has been developed to determine the quantity of cellulose after a catalytic reaction by using a tungsten carbide catalyst supported on activated carbon. Stepped separation of TGA curves was used for quantitative analysis where three thermal events were identified: moisture loss, cellulose decomposition and CO/CO 2 formation. An analytical curve was derived and applied to quantify the residual cellulose after catalytic reactions which were performed at various temperatures and reaction times. The catalytic conversion was calculated and compared to the standard gravimetric method. Results showed that catalytic cellulose conversion can be determined using TGA and exhibits lower uncertainty (±2%) when compared to gravimetric determination (±5%). Therefore, it is a simple and relatively inexpensive method to determine catalytic

  16. Determination of effective moisture diffusivity and drying kinetics for poplar sawdust by thermogravimetric analysis under isothermal condition.

    Science.gov (United States)

    Chen, Dengyu; Zheng, Yan; Zhu, Xifeng

    2012-03-01

    The current study presents a thermogravimetric method to determine the effective moisture diffusivity and drying kinetics of biomass. Drying experiments on poplar sawdust were performed at four temperatures (60, 70, 80, and 90°C) by a thermogravimetric analyzer (TGA). The major assumption in experimentally determining effective diffusivity by Fick's diffusion equation is that drying is mass transfer limited and temperature remains isothermal during drying. The results indicated that TGA could well achieve these determining conditions. The drying process of sawdust mostly took place in the falling rate period. Midilli-Kucuk model showed the best fit for all experimental data. The effective diffusivity values changed from 9.38 × 10(-10)m(2)/s to 1.38 × 10(-9)m(2)/s within the given temperature range, and the activation energy was calculated to be 12.3 kJ/mol. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Combustion studies of coal derived solid fuels by thermogravimetric analysis. III. Correlation between burnout temperature and carbon combustion efficiency

    Science.gov (United States)

    Rostam-Abadi, M.; DeBarr, J.A.; Chen, W.T.

    1990-01-01

    Burning profiles of 35-53 ??m size fractions of an Illinois coal and three partially devolatilized coals prepared from the original coal were obtained using a thermogravimetric analyzer. The burning profile burnout temperatures were higher for lower volatile fuels and correlated well with carbon combustion efficiencies of the fuels when burned in a laboratory-scale laminar flow reactor. Fuels with higher burnout temperatures had lower carbon combustion efficiencies under various time-temperature conditions in the laboratory-scale reactor. ?? 1990.

  18. DETERMINATION OF SATURATION VAPOR PRESSURE OF LOW VOLATILE SUBSTANCES THROUGH THE STUDY OF EVAPORATION RATE BY THERMOGRAVIMETRIC ANALYSIS

    Directory of Open Access Journals (Sweden)

    R. V. Ralys

    2015-11-01

    Full Text Available Subject of Study.Research of vapor pressure of low volatile substances is a complicated problem due to both direct experimental implementation complexity and, most significantly, the issues faced correctness of the analysis and processing of experimental data. That is why it is usually required engaging the reference substances (with vapor pressures well studied. The latter drastically reduces the effectiveness of the experimental methods used and narrows their applicability. The paper deals with an approach to the evaporation process description (sublimation of low volatile substances based on molecular kinetic description in view of diffusive and convection processes. The proposed approach relies on experimental thermogravimetricfindingsina wide range of temperatures, flow rates ofthe purge gas and time. Method. A new approach is based on the calculation of the vapor pressure and uses the data about the speed of evaporation by thermogravimetric analysis depending on the temperature, the flow rate of the purge gas, and the evaporation time. The basis for calculation is the diffusion-kinetic description of the process of evaporation (mass loss of the substance from the exposed surface. The method is applicable to determine the thermodynamic characteristics for both the evaporation (the equilibrium liquid - vapor and sublimation (the equilibrium solid - vapor. We proposed the appropriate method of the experiment and analysis of its data in order to find the saturated vapor pressure of individual substances of low volatility. Main Results. The method has been tested on substances with insufficiently reliable and complete study of the thermodynamic characteristics but, despite this, are often used (because of the other data limitations as reference ones. The vaporization process (liquid-vapor has been studied for di-n-butyl phthalate C16H22O4 at 323,15–443,15 К, and sublimation for benzoic acid C7H6O2at 303,15–183,15 К. Both processes have

  19. Improvenments in environmental trace analysis by GC-IR and LC-IR.

    NARCIS (Netherlands)

    Visser, T.; Vredenbregt, M.J.; Jong, A.P.J.M.; Somsen, G.W.; Hankemeier, T.; Velthorst, N.H.; Gooijer, C.; Brinkman, U.A.T.

    1997-01-01

    Research has been carried out to enlarge the potential of infrared (IR) spectrometry as a detector in gas and liquid chromatography (GC and LC). The study has been directed to applications in environmental analysis. Examples of recently obtained results are presented. The analyte detectability of

  20. Electrodynamic thermogravimetric analyzer

    International Nuclear Information System (INIS)

    Spjut, R.E.; Bar-Ziv, E.; Sarofim, A.F.; Longwell, J.P.

    1986-01-01

    The design and operation of a new device for studying single-aerosol-particle kinetics at elevated temperatures, the electrodynamic thermogravimetric analyzer (EDTGA), was examined theoretically and experimentally. The completed device consists of an electrodynamic balance modified to permit particle heating by a CO 2 laser, temperature measurement by a three-color infrared-pyrometry system, and continuous weighing by a position-control system. In this paper, the position-control, particle-weight-measurement, heating, and temperature-measurement systems are described and their limitations examined

  1. Linearly Polarized IR Spectroscopy Theory and Applications for Structural Analysis

    CERN Document Server

    Kolev, Tsonko

    2011-01-01

    A technique that is useful in the study of pharmaceutical products and biological molecules, polarization IR spectroscopy has undergone continuous development since it first emerged almost 100 years ago. Capturing the state of the science as it exists today, "Linearly Polarized IR Spectroscopy: Theory and Applications for Structural Analysis" demonstrates how the technique can be properly utilized to obtain important information about the structure and spectral properties of oriented compounds. The book starts with the theoretical basis of linear-dichroic infrared (IR-LD) spectroscop

  2. Kinetics and evolved gas analysis for pyrolysis of food processing wastes using TGA/MS/FT-IR.

    Science.gov (United States)

    Özsin, Gamzenur; Pütün, Ayşe Eren

    2017-06-01

    The objective of this study was to identify the pyrolysis of different bio-waste produced by food processing industry in a comprehensible manner. For this purpose, pyrolysis behaviors of chestnut shells (CNS), cherry stones (CS) and grape seeds (GS) were investigated by thermogravimetric analysis (TGA) combined with a Fourier-transform infrared (FT-IR) spectrometer and a mass spectrometer (MS). In order to make available theoretical groundwork for biomass pyrolysis, activation energies were calculated with the help of four different model-free kinetic methods. The results are attributed to the complex reaction schemes which imply parallel, competitive and complex reactions during pyrolysis. During pyrolysis, the evolution of volatiles was also characterized by FT-IR and MS. The main evolved gases were determined as H 2 O, CO 2 and hydrocarbons such as CH 4 and temperature dependent profiles of the species were obtained. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Thermogravimetric analysis and TEM characterization of the oxidation and defect sites of carbon nanotubes synthesized by CVD of methane

    International Nuclear Information System (INIS)

    Li Haipeng; Zhao Naiqin; He Chunnian; Shi Chunsheng; Du Xiwen; Li Jiajun

    2008-01-01

    Changes in the thermogravimetrically determined oxidation behaviors of CVD-grown multi-walled carbon nanotubes (MWNTs) over Ni/Al catalyst with different Ni content were examined. Catalyst type was found to have a measurable impact upon nanotube stability, suggesting differing levels of crystalline perfection in the resulting nanotubes. With increasing the Ni content in the Ni/Al catalyst, the CNTs obtained became less stable during heat treatment in air. Furthermore, high-resolution transmission electron microscopy was employed to investigate the defect sites of as-grown MWNTs. The results provide evidence showing that defect sites along the walls and at the ends of the raw MWNTs facilitate the thermal oxidative destruction of the nanotubes

  4. Analysis of Mechanical and Thermogravimetric Properties of Composite Materials Based on PVA/MWCNT and Styrene-Acrylic Copolymer/MWCNT

    Science.gov (United States)

    Volynets, N. I.; Poddubskaya, O. G.; Demidenko, M. I.; Lyubimov, A. G.; Kuzhir, P. P.; Suslyaev, V. I.; Pletnev, M. A.; Zicans, Janis

    2017-08-01

    Mechanical and thermogravimetric properties of polymer composite materials with various concentrations of multiwalled carbon nanotubes effectively shielding radiation in the radio frequency (20 Hz - 1 MHz) and microwave (26-36 GHz) frequency ranges are studied. As a matrix, widely available polymeric materials, such as polyvinyl acetate and styrene-acrylate, were used in the form of dispersions. From the analysis of the obtained experimental data, it was shown that the introduction of carbon nanotubes into the polymer matrix makes it possible to increase mechanical properties and thermal stability of composite materials.

  5. Analysis of effect of cable degradation on SPND IR calculation

    International Nuclear Information System (INIS)

    Tamboli, P.K.; Sharma, A.; Prasad, A.D.; Singh, Nita; Antony, J.; Kelkar, M.G.; Kaurav, Reetesh; Pramanik, M.

    2013-01-01

    Neutron flux is the most vital parameter in the nuclear reactor safety against Neutronic over power. The modern days Indian PHWRs with large core size are loosely coupled reactors and hence In-core Self Power Neutron Detectors (SPNDs) are most suitable for monitoring local neutron power for generating Regional Overpower Trip. However the SPNDs and its Mineral Insulation Cable are prone to IR loss due to use of ceramic insulation which are highly hygroscopic. The present paper covers the online analysis of IR f degraded cable as per the surveillance requirement of monitoring the IR to assess the healthiness of SPNDs which are part of SSC/SSE for Reactor Protection Systems. The paper also proposes an alternative method for monitoring IR for startup//low power range when SPND signals are yet to pick up and Reactor Control and Protection are based on out of core Ionization Chambers. (author)

  6. The degree of hydration assessment of blended cement pastes by differential thermal and thermogravimetric analysis. Morphological evolution of the solid phases

    International Nuclear Information System (INIS)

    Monteagudo, S.M.; Moragues, A.; Gálvez, J.C.; Casati, M.J.; Reyes, E.

    2014-01-01

    Highlights: • A proposal of hydration degree calculation for blended cement pastes is presented. • The method is based both on the contributions of various authors and on DTA–TG results. • Paste and mortar specimens with BFS, FA and SF mineral admixtures were used. • The evaluation of CH gives information on hydration and pozzolanic reactions. • The assessment of α provides an insight into future strength evolution. - Abstract: The degree of hydration assessment of cement paste from differential thermal and thermogravimetric analysis data has been performed by several authors that have offered a number of proposals for technical application to blended cements. In this paper, two calculation methods are studied in detail. Then, a proposal of the degree of hydration calculation for blended cements, based on the analysis of experimental results of DTA–TG, is presented. The proposed method combines the contributions of the authors and allows straightforward calculation of the degree of hydration from the experimental results. Validation of the methodology was performed by macroscopic and microstructural tests through paste and mortar specimens with blast furnace slag, flying ash and silica fume mineral admixtures bei(g)ng used. Tests of scanning electron microscopy with an energy dispersive analyser on paste specimens, and of mechanical strength on mortar specimens with the same percentages of substitution, were performed. They showed good agreement with the information derived from the differential thermal and thermogravimetric analysis data

  7. Evaluation of co-pyrolysis petrochemical wastewater sludge with lignite in a thermogravimetric analyzer and a packed-bed reactor: Pyrolysis characteristics, kinetics, and products analysis.

    Science.gov (United States)

    Mu, Lin; Chen, Jianbiao; Yao, Pikai; Zhou, Dapeng; Zhao, Liang; Yin, Hongchao

    2016-12-01

    Co-pyrolysis characteristics of petrochemical wastewater sludge and Huolinhe lignite were investigated using thermogravimetric analyzer and packed-bed reactor coupled with Fourier transform infrared spectrometer and gas chromatography. The pyrolysis characteristics of the blends at various sludge blending ratios were compared with those of the individual materials. Thermogravimetric experiments showed that the interactions between the blends were beneficial to generate more residues. In packed-bed reactor, synergetic effects promoted the release of gas products and left less liquid and solid products than those calculated by additive manner. Fourier transform infrared spectrometer analysis showed that main functional groups in chars gradually disappeared with pyrolysis temperatures increasing, and H 2 O, CH 4 , CO, and CO 2 appeared in volatiles during pyrolysis. Gas compositions analysis indicated that, the yields of H 2 and CO clearly increased as the pyrolysis temperature and sludge blending ratio increasing, while the changes of CH 4 and CO 2 yields were relatively complex. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Investigation of the effects of phase transformations in micro and nano aluminum powders on kinetics of oxidation using thermogravimetric analysis.

    Science.gov (United States)

    Saceleanu, Florin; Atashin, Sanam; Wen, John Z

    2017-07-26

    Aluminum micro and nanoparticles are key ingredients in the synthesis of nano energetic materials. Hence it is important to characterize the kinetics and the rate controlling process of their oxidation. The literature shows that the mass diffusion and phase transformation within the aluminum oxide shell are important. However, the description of physical processes regarding simultaneous oxidation and phase transformation is lacking. In this paper, the controlled thermogravimetric (TGA) oxidation of 40-60 nm and 1 µm Al powders is investigated at constant heating rates and under isothermal conditions, respectively, upon varying the partial pressure of oxygen. It is found that the core-shell model of homogenous oxidation is applicable to explain the TGA results when the shell does not undergo phase transformation, which predicts the apparent activation energy in good agreement with the literature data. On the other hand, the simultaneous oxidation and phase transformation is able to be addressed using the JMAK model which reveals key parameters of the rate controlling processes. Mass diffusion is indeed rate determining during the oxidation of Al micro and nanopowders while the kinetics of the reaction is fast. Unlike the micron powders, the particle size distribution has a significant effect on the shape of the oxidation curves of the nanopowders.

  9. Kinetic analysis on the non-isothermal degradation of plum stone waste by thermogravimetric analysis and integral master-plots method.

    Science.gov (United States)

    Ceylan, Selim

    2015-04-01

    In this study, pyrolysis of plum stone was investigated by thermogravimetric analysis in a nitrogen atmosphere at heating rates of 5, 10, 20 and 40 °C min(-1). Pyrolysis characteristics and the thermal-decomposition rate were significantly affected by variation in the heating rate. However, the heating rate slightly affected the total yield of the volatile matters. Activation energy of the pyrolysis reaction was evaluated by model-free methods, Friedman and Kissingere-Akahirae-Sunose. Results of the Master-Plots method indicated that the most probable reaction model function was the nth order reaction model function as f(x) = (1-x) (3.11), A = 8.02x10(12) under a mean activation energy of 150.61 kJ mol(-1). Proximate and ultimate analysis showed that plum stone can be considered as a favourable source for energy production owing to its low moisture and ash content, and high volatile matter ratio and moderate heating value. © The Author(s) 2015.

  10. IR spectral analysis for the diagnostics of crust earthquake precursors

    Directory of Open Access Journals (Sweden)

    R. M. Umarkhodgaev

    2012-11-01

    Full Text Available Some possible physical processes are analysed that cause, under the condition of additional ionisation in a pre-breakdown electric field, emissions in the infrared (IR interval. The atmospheric transparency region of the IR spectrum at wavelengths of 7–15 μm is taken into account. This transparency region corresponds to spectral lines of small atmospheric constituents like CH4, CO2, N2O, NO2, NO, and O3. The possible intensities of the IR emissions observable in laboratories and in nature are estimated. The acceleration process of the electrons in the pre-breakdown electrical field before its adhesion to the molecules is analyzed. For daytime conditions, modifications of the adsorption spectra of the scattered solar emissions are studied; for nighttime, variations of emission spectra may be used for the analysis.

  11. Pyrolysis of biofuels of the future: Sewage sludge and microalgae – Thermogravimetric analysis and modelling of the pyrolysis under different temperature conditions

    International Nuclear Information System (INIS)

    Soria-Verdugo, Antonio; Goos, Elke; Morato-Godino, Andrés; García-Hernando, Nestor; Riedel, Uwe

    2017-01-01

    Highlights: • Pyrolysis of microalgae and sewage sludge is studied by thermogravimetric analysis. • Accurate values of the kinetic parameters of the pyrolysis reaction are reported. • Pyrolysis is modeled for parabolic and exponential temperature increases. • Estimations of the model are compared with experimental measurements in TGA. • Excellent agreement is reached between the model estimations and the experiments. - Abstract: The pyrolysis process of both microalgae and sewage sludge was investigated separately, by means of non-isothermal thermogravimetric analysis. The Distributed Activation Energy Model (DAEM) was employed to obtain the pyrolysis kinetic parameters of the samples, i.e. the activation energy E_a and the pre-exponential factor k_0. Nine different pyrolysis tests at different constant heating rates were conducted for each sample in a thermogravimetric analyzer (TGA) to obtain accurate values of the pyrolysis kinetic parameters when applying DAEM. The accurate values of the activation energy and the pre-exponential factor that characterize the pyrolysis reaction of Chlorella vulgaris and sewage sludge were reported, together with their associated uncertainties. The activation energy and pre-exponential factor for the C. vulgaris vary between 150–250 kJ/mol and 10"1"0–10"1"5 s"−"1 respectively, whereas values ranging from 200 to 400 kJ/mol were obtained for the sewage sludge activation energy, and from 10"1"5 to 10"2"5 s"−"1 for its pre-exponential factor. These values of E_a and k_0 were employed to estimate the evolution of the reacted fraction with temperature during the pyrolysis of the samples under exponential and parabolic temperature increases, more typical for the pyrolysis reaction of fuel particles in industrial reactors. The estimations of the relation between the reacted fraction and the temperature for exponential and parabolic temperature increases were found to be in good agreement with the experimental values

  12. Thermal transformation of bioactive caffeic acid on fumed silica seen by UV-Vis spectroscopy, thermogravimetric analysis, temperature programmed desorption mass spectrometry and quantum chemical methods.

    Science.gov (United States)

    Kulik, Tetiana V; Lipkovska, Natalia O; Barvinchenko, Valentyna M; Palyanytsya, Borys B; Kazakova, Olga A; Dudik, Olesia O; Menyhárd, Alfréd; László, Krisztina

    2016-05-15

    Thermochemical studies of hydroxycinnamic acid derivatives and their surface complexes are important for the pharmaceutical industry, medicine and for the development of technologies of heterogeneous biomass pyrolysis. In this study, structural and thermal transformations of caffeic acid complexes on silica surfaces were studied by UV-Vis spectroscopy, thermogravimetric analysis, temperature programmed desorption mass spectrometry (TPD MS) and quantum chemical methods. Two types of caffeic acid surface complexes are found to form through phenolic or carboxyl groups. The kinetic parameters of the chemical reactions of caffeic acid on silica surface are calculated. The mechanisms of thermal transformations of the caffeic chemisorbed surface complexes are proposed. Thermal decomposition of caffeic acid complex chemisorbed through grafted ester group proceeds via three parallel reactions, producing ketene, vinyl and acetylene derivatives of 1,2-dihydroxybenzene. Immobilization of phenolic acids on the silica surface improves greatly their thermal stability. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Thermogravimetric and kinetic study of methylolmelamine ...

    African Journals Online (AJOL)

    Some salient properties of cotton cellulose which requires it to be treated with additives to improve its versatility were examined taken into consideration, the molecular structure. Thermogravimetric analysis of the cotton fabric and the treated cotton fabric were carried out in an improvised muffled furnace. The result was in ...

  14. Development and in house validation of a new thermogravimetric method for water content analysis in soft brown sugar.

    Science.gov (United States)

    Ducat, Giseli; Felsner, Maria L; da Costa Neto, Pedro R; Quináia, Sueli P

    2015-06-15

    Recently the use of brown sugar has increased due to its nutritional characteristics, thus requiring a more rigid quality control. The development of a method for water content analysis in soft brown sugar is carried out for the first time by TG/DTA with application of different statistical tests. The results of the optimization study suggest that heating rates of 5°C min(-1) and an alumina sample holder improve the efficiency of the drying process. The validation study showed that thermo gravimetry presents good accuracy and precision for water content analysis in soft brown sugar samples. This technique offers advantages over other analytical methods as it does not use toxic and costly reagents or solvents, it does not need any sample preparation, and it allows the identification of the temperature at which water is completely eliminated in relation to other volatile degradation products. This is an important advantage over the official method (loss on drying). Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Characterization of Synthesized and Commercial Forms of Magnesium Stearate Using Differential Scanning Calorimetry, Thermogravimetric Analysis, Powder X-Ray Diffraction, and Solid-State NMR Spectroscopy.

    Science.gov (United States)

    Delaney, Sean P; Nethercott, Matthew J; Mays, Christopher J; Winquist, Nickolas T; Arthur, Donia; Calahan, Julie L; Sethi, Manish; Pardue, Daniel S; Kim, Junghyun; Amidon, Gregory; Munson, Eric J

    2017-01-01

    Magnesium stearate is the salt of a complex mixture of fatty acids, with the majority being stearate and palmitate. It has multiple crystalline forms and, potentially, an amorphous form. Magnesium stearate is used in the pharmaceutical manufacturing industry as a powder lubricant, and typically is added at low levels (∼1%) during the manufacturing process and blended for a relatively short time (∼5 min). Proper levels and mixing times are needed, as too short a mixing time or too small a quantity will result in improper lubrication, and too much can negatively impact dissolution rates. The complex mixture of multiple fatty acids and crystalline forms in magnesium stearate leads to variability between commercial sources, and switching between sources can impact both the amount of lubricant and mixing time needed for proper lubrication. In order to better understand the complex nature of magnesium stearate, a variety of analytical techniques were used to characterize both synthesized and commercial magnesium stearate samples. The results show that correlation among differential scanning calorimetry, thermogravimetric analysis, solid-state NMR spectroscopy, and other techniques provides a unique insight into the forms of magnesium stearate. Finally, the ability to monitor form changes of magnesium stearate in an intact tablet using solid-state NMR spectroscopy is shown. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  16. Thermogravimetric analysis and kinetic modeling of low-transition-temperature mixtures pretreated oil palm empty fruit bunch for possible maximum yield of pyrolysis oil.

    Science.gov (United States)

    Yiin, Chung Loong; Yusup, Suzana; Quitain, Armando T; Uemura, Yoshimitsu; Sasaki, Mitsuru; Kida, Tetsuya

    2018-05-01

    The impacts of low-transition-temperature mixtures (LTTMs) pretreatment on thermal decomposition and kinetics of empty fruit bunch (EFB) were investigated by thermogravimetric analysis. EFB was pretreated with the LTTMs under different duration of pretreatment which enabled various degrees of alteration to their structure. The TG-DTG curves showed that LTTMs pretreatment on EFB shifted the temperature and rate of decomposition to higher values. The EFB pretreated with sucrose and choline chloride-based LTTMs had attained the highest mass loss of volatile matter (78.69% and 75.71%) after 18 h of pretreatment. For monosodium glutamate-based LTTMs, the 24 h pretreated EFB had achieved the maximum mass loss (76.1%). Based on the Coats-Redfern integral method, the LTTMs pretreatment led to an increase in activation energy of the thermal decomposition of EFB from 80.00 to 82.82-94.80 kJ/mol. The activation energy was mainly affected by the demineralization and alteration in cellulose crystallinity after LTTMs pretreatment. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. Kinetic model of the thermal pyrolysis of chrome tanned leather treated with NaOH under different conditions using thermogravimetric analysis.

    Science.gov (United States)

    Bañón, E; Marcilla, A; García, A N; Martínez, P; León, M

    2016-02-01

    The thermal decomposition of chrome tanned leather before and after a soaking treatment with NaOH was studied using thermogravimetric analysis (TGA). The effect of the solution concentration (0.2M and 0.5M) and the soaking time (5min and 15min) was evaluated. TGA experiments at four heating rates (5, 10, 15 and 20°Cmin(-1)) were run in a nitrogen atmosphere for every treatment condition. A kinetic model was developed considering the effect of the three variables studied, i.e.: the NaOH solution concentration, the soaking time and the heating rate. The proposed model for chrome tanned leather pyrolysis involves a set of four reactions, i.e.: three independent nth order reactions, yielding the corresponding products and one of them undergoing a successive cero order reaction. The model was successfully applied simultaneously to all the experimental data obtained. The evaluation of the kinetic parameters obtained (activation energy, pre-exponential factor and reaction order) allowed a better understanding of the effect of the alkali treatment on these wastes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. A Study of the Oxidation Behaviour of Pile Grade A (PGA) Nuclear Graphite Using Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) and X-Ray Tomography (XRT).

    Science.gov (United States)

    Payne, Liam; Heard, Peter J; Scott, Thomas B

    2015-01-01

    Pile grade A (PGA) graphite was used as a material for moderating and reflecting neutrons in the UK's first generation Magnox nuclear power reactors. As all but one of these reactors are now shut down there is a need to understand the residual state of the material prior to decommissioning of the cores, in particular the location and concentration of key radio-contaminants such as 14C. The oxidation behaviour of unirradiated PGA graphite was studied, in the temperature range 600-1050°C, in air and nitrogen using thermogravimetric analysis, scanning electron microscopy and X-ray tomography to investigate the possibility of using thermal degradation techniques to examine 14C distribution within irradiated material. The thermal decomposition of PGA graphite was observed to follow the three oxidation regimes historically identified by previous workers with limited, uniform oxidation at temperatures below 600°C and substantial, external oxidation at higher temperatures. This work demonstrates that the different oxidation regimes of PGA graphite could be developed into a methodology to characterise the distribution and concentration of 14C in irradiated graphite by thermal treatment.

  19. Investigation of co-combustion characteristics of sewage sludge and coffee grounds mixtures using thermogravimetric analysis coupled to artificial neural networks modeling.

    Science.gov (United States)

    Chen, Jiacong; Liu, Jingyong; He, Yao; Huang, Limao; Sun, Shuiyu; Sun, Jian; Chang, KenLin; Kuo, Jiahong; Huang, Shaosong; Ning, Xunan

    2017-02-01

    Artificial neural network (ANN) modeling was applied to thermal data obtained by non-isothermal thermogravimetric analysis (TGA) from room temperature to 1000°C at three different heating rates in air to predict the TG curves of sewage sludge (SS) and coffee grounds (CG) mixtures. A good agreement between experimental and predicted data verified the accuracy of the ANN approach. The results of co-combustion showed that there were interactions between SS and CG, and the impacts were mostly positive. With the addition of CG, the mass loss rate and the reactivity of SS were increased while charring was reduced. Measured activation energies (E a ) determined by the Kissinger-Akahira-Sunose (KAS) and Ozawa-Flynn-Wall (OFW) methods deviated by <5%. The average value of E a (166.8kJ/mol by KAS and 168.8kJ/mol by OFW, respectively) was the lowest when the fraction of CG in the mixture was 40%. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. INFRARED SPECTRA, THERMOGRAVIMETRIC ANALYSIS AND ...

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  1. Thermogravimetric investigations of vanadium complexes

    International Nuclear Information System (INIS)

    Bechmann, W.; Uhlemann, E.; Ludwig, W.

    1987-01-01

    Extensive studies on oxovanadium(IV) and (V) complexes with bidentate chelating ligands include thermogravimetric investigations. TG, DTG, and DTA data provide additional facts to redox behaviour and stability of the complexes. These data also allow a critical appreciation of the given melting temperatures. (author)

  2. Investment casting using multi-jet modelling patterns: the thermogravimetric analysis of visijet® SR200 UV curable acrylate plastic

    International Nuclear Information System (INIS)

    Hafsa, M N; Ibrahim, M; Sharif, S

    2013-01-01

    Rapid Prototyping (RP) technology is actively studied to be implemented in Investment Casting (IC) process. Nowadays RP techniques are studied for their feasibility as IC master patterns, in terms of pattern collapsibility and drainage during burnout. The purpose of the study is to determine the characteristic of Visijet® SR200 acrylate material during burnout process. Traditional IC patterns made from wax have properties that limit their application in precision casting, especially for parts with thin geometries that readily break or deform when handled or dipped in the refractory slurry. Furthermore, it is not economical when producing a small number of parts. Non wax patterns fabricated for IC process, revealed ceramic shell cracking due to excessive thermal expansions, incomplete collapsibility of pattern during burnout, residual ash and poor surface finish. Thermogravimetric analysis (TGA) was used to measured the weight loss of acrylate material as the temperature was increased. TGA measured the change of material's mass as it is heated. It represents the decomposition temperature after being subjected to varying temperatures, as well as the amount of residual ash. In this experiment, the temperature range was from 20°C to 700°C with 5°C increment. Experiment results show the values of material's optimum reaction temperature and decomposing temperature of Visijet® SR200 acrylate. The percentages of remaining materials were also monitored throughout the process to obtain the amount of residual ash. All of the temperature values obtained is a resemblance for the actual burnout process and can be used as references

  3. A novel quantification method of pantaprazole sodium monohydrate in sesquihydrate by thermogravimetric analyzer.

    Science.gov (United States)

    Reddy, V Ranga; Rajmohan, M Anantha; Shilpa, R Laxmi; Raut, Dilip M; Naveenkumar, Kolla; Suryanarayana, M V; Mathad, Vijayavitthal T

    2007-04-11

    To demonstrate the applicability of thermogravimetric analyzer as a tool for the quantification of pantaprazole sodium monohydrate in sesquihydrate, studies have been conducted. Thermal analysis (DSC, TGA) crystallographic (PXRD) and spectroscopic techniques (FT-IR) were used for the characterization of the polymorphs. Thermogravimetric analysis (TGA) analysis was explored by high-resolution dynamic (Hi-Res-dynamic) and high-resolution modulated (Hi-Res-modulated) test procedures to quantify the hydrate polymorphic mixtures. The two polymorphic forms exhibited significant differences and good resolution in the second derivative thermogram generated by Hi-Res-modulated test procedure. Thus, the TGA with Hi-Res-modulated test procedure was considered for the quantification of monohydrate in sesquihydrate. The calibration plot was constructed from the known mixtures of two polymorphs by plotting the peak area of the second derivative thermogram against the weight percent of monohydrate. Using this novel approach, 1 wt% limit of detection (LOD) was achieved. The polymorphic purity results, obtained by TGA in Hi-Res-modulated test procedure were found to be in good agreement with the results predicted by FT-IR and was comparable with the actual values of the known polymorphic mixtures. The Hi-Res-modulated TGA technique is very simple and easy to perform the analysis.

  4. Thermogravimetric studies of vapour-aerosol interactions

    International Nuclear Information System (INIS)

    Henshaw, J.; Newland, M.S.; Wood, S.J.

    1991-01-01

    Thermogravimetric analysis has been used to study the interaction of iodine vapour with cadmium, silver and manganese monoxide substrates. These studies have demonstrated the importance of time-dependence data on reaction rates. Iodine did not react with manganese monoxide (as expected from thermodynamic considerations); however, extensive reaction did occur with silver and cadmium. Two rate limiting mechanisms were observed: mass transfer of iodine molecules from the gas phase (leading to linear reaction rates) and parabolic kinetics (ie inversely proportional to the extent of reaction) when the rate was limited by a diffusion process through the reaction product. (author)

  5. Preparation and thermogravimetric study of some uranyl phosphates

    International Nuclear Information System (INIS)

    Schaekers, J.M.

    1970-10-01

    The preparation of uranyl ammonium phosphate trihydrate (UAP = UO 2 NH 4 PO 4 .3H 2 O), acid uranyl phosphate tetrahydrate(AUP = UO 2 HPO 4 .4H 2 O) and neutral uranyl phosphate tetrahydrate (NUPT = (UO 2 ) 3 (PO 4 ) 2 .4H 2 O) was investigated during the data from the literature. The thermal decomposition in different atmospheres, such as air, oxygen, nitrogen and argon, was studied in the temperature range 25-1000 0 C. It was found that the pyrophosphate U 2 O 3 P 2 O 7 is a stable decomposition product of UAP as well as of AUP. A mixture of U 3 O 8 and U 2 O 3 P 2 O 7 is obtained when the NUPT is decomposed in an oxygen-free atmosphere. NUPT however is stable in an oxidising atmosphere. Hydrogen and carbon reductions were also carried out, and UO 2 or (UO) 2 P 2 O 7 as well as mixtures of these two products can be obtained, depending on the starting material and the reduction temperature. The different reduction and decomposition reactions were studied by means of thermogravimetric analysis, and activation energies were calculated where possible. I.R. spectral analysis was also used to identify various products with the same composition [af

  6. Nanomechanical IR spectroscopy for fast analysis of liquid-dispersed engineered nanomaterials

    OpenAIRE

    Andersen, Alina Joukainen; Yamada, Shoko; Ek, Pramod Kumar; Andresen, Thomas Lars; Boisen, Anja; Schmid, Silvan

    2016-01-01

    The proliferated use of engineered nanomaterials (ENMs), e.g. in nanomedicine, calls for novel techniques allowing for fast and sensitive analysis of minute samples. Here we present nanomechanical IR spectroscopy (NAM-IR) for chemical analysis of picograms of ENMs. ENMs are nebulized directly from dispersion and efficiently collected on nanomechanical string resonators through a non-diffusion limited sampling method. Even very small amounts of sample can convert absorbed IR light into a measu...

  7. US-LHC IR magnet error analysis and compensation

    International Nuclear Information System (INIS)

    Wei, J.; Ptitsin, V.; Pilat, F.; Tepikian, S.; Gelfand, N.; Wan, W.; Holt, J.

    1998-01-01

    This paper studies the impact of the insertion-region (IR) magnet field errors on LHC collision performance. Compensation schemes including magnet orientation optimization, body-end compensation, tuning shims, and local nonlinear correction are shown to be highly effective

  8. "Batch" kinetics in flow: online IR analysis and continuous control.

    Science.gov (United States)

    Moore, Jason S; Jensen, Klavs F

    2014-01-07

    Currently, kinetic data is either collected under steady-state conditions in flow or by generating time-series data in batch. Batch experiments are generally considered to be more suitable for the generation of kinetic data because of the ability to collect data from many time points in a single experiment. Now, a method that rapidly generates time-series reaction data from flow reactors by continuously manipulating the flow rate and reaction temperature has been developed. This approach makes use of inline IR analysis and an automated microreactor system, which allowed for rapid and tight control of the operating conditions. The conversion/residence time profiles at several temperatures were used to fit parameters to a kinetic model. This method requires significantly less time and a smaller amount of starting material compared to one-at-a-time flow experiments, and thus allows for the rapid generation of kinetic data. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Nanomechanical IR spectroscopy for fast analysis of liquid-dispersed engineered nanomaterials

    DEFF Research Database (Denmark)

    Andersen, Alina Joukainen; Yamada, Shoko; Ek, Pramod Kumar

    2016-01-01

    The proliferated use of engineered nanomaterials (ENMs), e.g. in nanomedicine, calls for novel techniques allowing for fast and sensitive analysis of minute samples. Here we present nanomechanical IR spectroscopy (NAM-IR) for chemical analysis of picograms of ENMs. ENMs are nebulized directly from...

  10. Thermogravimetric study of vinpocetine suppository

    Directory of Open Access Journals (Sweden)

    N. А. Nаgоrnaya

    2014-02-01

    Full Text Available Introduction. Development of technology is the one of the main stage in creation of new medications. Technological process of suppository manufacturing includes sufficiently long thermoprocessing during suppository base making, addition of the active substances and homogenisation. This makes risk of chemical and physical transformations of active substances and excipients in suppository which can be destroyed and changed pharmacologicaly. Use of thermogravimetric analyses in pharmaceutical technology allows to study possibility of chemical interactions of components in the wide range of temperature. The aim of this work was to study thermoprocessing effects on suppository base with vinpocetine in temperature range of technological process of suppository manufacturing. Object. Vinpocetine rectal suppository (with 0,5% of surface-active substances, active substance (vinpocetine and excipients (twin 80, cacao oil were used as the objects of thermogravimetric investigation. Thermogravimetric analyses was carried out on the derivatograph «Shimadzu DTG-60» (Japan with the platinum-rhodium thermocouple by heating from 25°C to 200°C in the aluminium crucible. α-Al2O3 was used as standard. Heating speed was 10ºС in minute. Model mass was 14,23 – 34,4 mg. Conclusions. It was established that cacao oil is thermolabile substance with melting temperature 41,32 ºС. Surface-active substance twin 80 displays thermostability from 30 tо 100ºС. Vinpocetine derivatogramme confirmed its thermostability in temperature range from 30 tо 154 ºС. Derivatogramme of vinpocetine rectal suppository 0,01 and suppository base displayed the absence of critical temperature lower 100ºС. Insignificant mass loss (0,21% shows that fact. Investigation of composition over 100ºС wasn’t carried out because these temperatures aren’t used in technological process of suppository manufacturing. Presence of thermal effects on derivatogramme of vinpocetine rectal

  11. Automation of a thermogravimetric equipment

    International Nuclear Information System (INIS)

    Mussio, L.; Castiglioni, J.; Diano, W.

    1987-01-01

    A low cost automation of some instruments by means of simple electronic circuits and a microcomputer Apple IIe. type is discussed. The electronic circuits described are: a) a position detector including phototransistors connected as differential amplifier; b) a current source that, using the error signal of the position detector, changes the current through the coil of an electromagnetic balance to restore its zero position; c) a proportional temperature controller, zero volt switching to drive a furnace to a desired temperature; d) an interface temperature regulator-microcomputer to control the temperature regulator by software; e) a multiplexer for an analog input of a commercial interface. Those circuits are applied in a thermogravimetric equipment used also for vapours adsorption. A program in block diagram form is included and is able to record change of mass, time, furnace temperature and to drive the temperature regulator in order to have the heating rates or the temperature plateaux needed for the experiment. (author) [pt

  12. Nanomechanical IR Spectroscopy for the fast analysis of picogram samples of engineered nanomaterials

    DEFF Research Database (Denmark)

    Andersen, Alina Joukainen; Ek, Pramod Kumar; Andresen, Thomas Lars

    2014-01-01

    The proliferation of engineered nanomaterials (ENMs), e.g. in nanomedicine, demands for novel sensitive techniques allowing for the analysis of minute samples. We present nanoelectromechanical system-based IR spectroscopy (NEMS-IR) of picograms of polymeric micelles. The micelles are nebulized...

  13. IR spectral analysis for the diagnostics of crust earthquake precursors

    Science.gov (United States)

    Umarkhodgaev, R. M.; Liperovsky, V. A.; Mikhailin, V. V.; Meister, C.-V.; Naumov, D. Ju

    2012-04-01

    In regions of future earthquakes, a few days before the seismic shock, the emanation of radon and hydrogen is being observed, which causes clouds of increased ionisation in the atmosphere. In the present work the possible diagnostics of these clouds using infrared (IR) spectroscopy is considered, which may be important and useful for the general geophysical system of earthquake prediction and the observation of industrial emissions of radioactive materials into the atmosphere. Some possible physical processes are analysed, which cause, under the condition of additional ionisation in a pre-breakdown electrical field, emissions in the IR interval. In doing so, the transparency region of the IR spectrum at wavelengths of 7-15 μm is taken into account. This transparency region corresponds to spectral lines of small atmospheric constituents like CH4, CO2, N2O, NO2, NO, and O3. The possible intensities of the IR emissions observable in laboratories and in nature are estimated. The acceleration process of the electrons in the pre-breakdown electrical field before its adhesion to the molecules is analysed. The laboratory equipment for the investigation of the IR absorption spectrum is constructed for the cases of normal and decreased atmospheric pressures. The syntheses of ozone and nitrous oxides are performed in the barrier discharge. It is studied if the products of the syntheses may be used to model atmospheric processes where these components take part. Spectra of products of the syntheses in the wavelength region of 2-10 μm are observed and analysed. A device is created for the syntheses and accumulation of nitrous oxides. Experiments to observe the IR-spectra of ozone and nitrous oxides during the syntheses and during the further evolution of these molecules are performed. For the earthquake prediction, practically, the investigation of emission spectra is most important, but during the laboratory experiments, the radiation of the excited molecules is shifted by a

  14. IR and UV spectroscopic analysis of TBP complexes

    International Nuclear Information System (INIS)

    Azzouz, A.; Berrak, A.; Seridi, L.; Attou, M.

    1985-06-01

    The complexity of TBP molecule and the limited number of references stimulated the elaboration of this report. The spectroscopic of TBP and its complexes in the IR and UV fields permitted to elucidate or to confirm certain aspects concerning the solvation phenomenum. In IR spectroscopy, the stretching band of the P→O bond only is characteristic of the complex formed. The position of this band gives sufficient information about the kind and the stability of a complex. The TBP electronic spectra are characterized by two bands (200-220 nm) 1 and (268-290 nm) 2 whose intensity ratio (2/1) is about 0,13. The solvent nature seems to influence the positions of these bands and that of the inflexion point. The band 2 disappears when the TBP is complexed and the position and the intensity of the band 1 depend upon the complex nature

  15. Thermogravimetric measurements of liquid vapor pressure

    International Nuclear Information System (INIS)

    Rong Yunhong; Gregson, Christopher M.; Parker, Alan

    2012-01-01

    Highlights: ► Rapid determination of vapor pressure by TGA. ► Demonstration of limitations of currently available approaches in literature. ► New model for vapor pressure assessment of small size samples in TGA. ► New model accounts for vapor diffusion and sample geometry and measures vapor pressure normally within 10%. - Abstract: A method was developed using thermo-gravimetric analysis (TGA) to determine the vapor pressure of volatile liquids. This is achieved by measuring the rate of evaporation (mass loss) of a pure liquid contained within a cylindrical pan. The influence of factors like sample geometry and vapor diffusion on evaporation rate are discussed. The measurement can be performed across a wide range of temperature yielding reasonable results up to 10 kPa. This approach may be useful as a rapid and automatable method for measuring the volatility of flavor and fragrance raw materials.

  16. Thermogravimetric study of rare earth concentrates

    International Nuclear Information System (INIS)

    Delyagejd, V.V.; Anisimova, V.N.; Eremenko, Z.V.; Kutsev, V.S.

    1974-01-01

    Methods of thermogravimetric, chemical and phase analysis were used in measuring the concentration of rare-earth elements of different origins. At temperatures 400-800 deg C a gradual decomposition of fluorocarbonates takes place leading to the formation of derivatives of corresponding oxides and oxyfluorides. For concentrates containing siderite the process takes place at 550-600 deg C followed by oxidation of bivalent iron into trivalent state. Reaction of rare-earth elements with sodium carbonate and the increase in the concentration of the latter results in a narrowing down of the interval of temperatures at which decomposition takes place. Under these conditions an intense reaction and a fusion take place leading to the formation of eutectic at 500-600 deg C and further synthesis of sodium fluoride and oxyfluoride derivatives of calcium and rare-earth elements

  17. Thermogravimetric investigations of cream with minoxidil

    Directory of Open Access Journals (Sweden)

    I. V. Gnitko

    2016-12-01

    Full Text Available Minoxidil is one of the most effective and modern medications, which is used in modern trichology for hair growth stimulation in case of androgenic and other forms of alopecia. Clinical effect of this substance is caused by the intensification of metabolic processes in the skin due to intensification of microcirculation. For local application domestic dermatology uses imported minoxidil medicines in form of alcohol-water lotions and aerosols. The use of semisolid dosage form with minoxidil for external administration will allow to increase its efficacy and will widen the arsenal of domestic pharmacotherapeutic agents for hair growth stimulation. Rational composition of minoxidil semisolid dosage form for external use with 2% of active substance has been developed at the Department of Medicinal Preparations Technology, Zaporozhye State Medical University as a result of complex physical-chemical, microbiological and biopharmaceutical investigations. The aim of this work is the study of thermal treatment effects of cream-mask with minoxidil for external use over the temperature range, which is used in technological process of this dosage form manufacturing. Materials and methods. Cream with 2% of minoxidil on the emulsion base and its excipients have been used as the object for the thermogravimetric investigations. Thermogravimetric analysis has been carried out on the derivatograph «Shimadzu DTG-60», Japan, with the platinum and platinum-rhodium thermopair with samples’ heating in aluminium crucibles from 25 to 200ºС. Results. According to thermogravimetric experimental data minoxidil is a thermal stable substance from 26 to 240ºС. During experimental process insignificant endothermic effect was determined at 191,72ºС. However the mass of the example to the end of experiment practically didn’t change (decrease on 0,32%. Thermal effects on the derivatogram of minoxidil emulsion cream match with thermal effects of the base components and

  18. Air oxidation of Zr65Cu17.5Ni10Al7.5 in its amorphous and supercooled liquid states, studied by thermogravimetric analysis

    International Nuclear Information System (INIS)

    Dhawan, A.; Sharma, S.K.; Raetzke, K.; Faupel, F.

    2003-01-01

    The oxidation behaviour of the bulk amorphous alloy Zr 65 Cu 17.5 Ni 10 Al 7.5 was studied in air at various temperatures in the temperature range 591-732 K using a thermogravimetric analyser (TGA). The oxidation kinetics of the alloy obeys the parabolic rate law showing two different linear regions (in the plots of mass gain versus square root of oxidation time) which are attributed to the amorphous and the supercooled liquid states of the alloy. The value of the activation energy Q for the amorphous state as calculated from the temperature dependence of the rate constants is found to be 1.80±0.1 eV and the corresponding value obtained for the supercooled liquid state is 1.20±0.1 eV. It is suggested that the rate controlling process during oxidation of the amorphous state is the back-diffusion of Ni, and possibly Cu also, while the oxidation in the supercooled liquid state is dominated by the inward diffusion of oxygen. (copyright 2003 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  19. Preparation, thermogravimetric study and infrared spectra of rare earth acetates

    International Nuclear Information System (INIS)

    Graehlert, X.; Starke, M.

    1992-01-01

    The anhydrous and the hydrated acetates of Ho, Er, Tm, Yb and Lu have been prepared. The compounds obtained have been investigated by thermogravimetric analysis and infrared spectroscopy. The thermal decomposition of the rare earth acetates may proceed via various steps. It depends on both the number of crystal water molecules in the acetates and the rare earth element's behaviour. (orig.)

  20. Hydrogenated fullerenes in space: FT-IR spectra analysis

    International Nuclear Information System (INIS)

    El-Barbary, A. A.

    2016-01-01

    Fullerenes and hydrogenated fullerenes are found in circumstellar and interstellar environments. But the determination structures for the detected bands in the interstellar and circumstellar space are not completely understood so far. For that purpose, the aim of this article is to provide all possible infrared spectra for C 20 and C 60 fullerenes and their hydrogenated fullerenes. Density Functional theory (DFT) is applied using B3LYP exchange-functional with basis set 6–31G(d, p). The Fourier transform infrared spectroscopy (FT-IR) is found to be capable of distinguishing between fullerenes, mono hydrogenated fullerenes and fully hydrogenated fullerenes. In addition, deposition of one hydrogen atom outside the fully hydrogenated fullerenes is found to be distinguished by forming H 2 molecule at peak around 4440 cm −1 . However, deposition of one hydrogen atom inside the fully hydrogenated fullerenes cannot be distinguished. The obtained spectral structures are analyzed and are compared with available experimental results.

  1. A study on growth and pyrolysis characteristics of microalgae using Thermogravimetric Analysis-Infrared Spectroscopy and synchrotron Fourier Transform Infrared Spectroscopy.

    Science.gov (United States)

    Li, Fanghua; Srivatsa, Srikanth Chakravartula; Batchelor, Warren; Bhattacharya, Sankar

    2017-04-01

    This two-part study firstly investigated Tetraselmis suecica grown in different CO 2 (0.04-15%v/v) concentration through indoor and outdoor cultivation systems. A high CO 2 concentration led to a high lipid content, and low nitrogen and oxygen content, which are desirable for transport fuel production. Pyrolysis characteristics were investigated by TG-IR and synchrotron IR microscopy. The results show Tetraselmis suecica grown in 10%CO 2 had the highest decomposition rate corresponding to more volatile products produced during the main thermal cracking stage and derived from protein-and lipid-corresponding functional groups. Moreover, a high reaction temperature and CO 2 concentration resulted in a low retention of surface functional groups. The nitrogen functional groups initially decomposed at a temperature range of 250-300°C and still remained at 550°C, while the lipid-corresponding functional groups completely disappeared at a temperature range of 400-500°C. Besides, the decomposition of chemical components followed the order of carbohydrate, protein and lipid. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Hydrogenated fullerenes in space: FT-IR spectra analysis

    Energy Technology Data Exchange (ETDEWEB)

    El-Barbary, A. A. [Physics Department, Faculty of Education, Ain-Shams University, Cairo, Egypt Physics Department, Faculty of Science, Jazan University, Jazan (Saudi Arabia)

    2016-06-10

    Fullerenes and hydrogenated fullerenes are found in circumstellar and interstellar environments. But the determination structures for the detected bands in the interstellar and circumstellar space are not completely understood so far. For that purpose, the aim of this article is to provide all possible infrared spectra for C{sub 20} and C{sub 60} fullerenes and their hydrogenated fullerenes. Density Functional theory (DFT) is applied using B3LYP exchange-functional with basis set 6–31G(d, p). The Fourier transform infrared spectroscopy (FT-IR) is found to be capable of distinguishing between fullerenes, mono hydrogenated fullerenes and fully hydrogenated fullerenes. In addition, deposition of one hydrogen atom outside the fully hydrogenated fullerenes is found to be distinguished by forming H{sub 2} molecule at peak around 4440 cm{sup −1}. However, deposition of one hydrogen atom inside the fully hydrogenated fullerenes cannot be distinguished. The obtained spectral structures are analyzed and are compared with available experimental results.

  3. Development of IR Contrast Data Analysis Application for Characterizing Delaminations in Graphite-Epoxy Structures

    Science.gov (United States)

    Havican, Marie

    2012-01-01

    Objective: Develop infrared (IR) flash thermography application based on use of a calibration standard for inspecting graphite-epoxy laminated/honeycomb structures. Background: Graphite/Epoxy composites (laminated and honeycomb) are widely used on NASA programs. Composite materials are susceptible for impact damage that is not readily detected by visual inspection. IR inspection can provide required sensitivity to detect surface damage in composites during manufacturing and during service. IR contrast analysis can provide characterization of depth, size and gap thickness of impact damage. Benefits/Payoffs: The research provides an empirical method of calibrating the flash thermography response in nondestructive evaluation. A physical calibration standard with artificial flaws such as flat bottom holes with desired diameter and depth values in a desired material is used in calibration. The research devises several probability of detection (POD) analysis approaches to enable cost effective POD study to meet program requirements.

  4. Thermogravimetric analysis, PXRD, EDX and XPS study of chrysocolla (Cu,Al)2H2Si2O5(OH)4·nH2O-structural implications

    International Nuclear Information System (INIS)

    Frost, Ray L.; Xi, Yunfei; Wood, Barry J.

    2012-01-01

    Highlights: ► We have undertaken a TG X PS study of the mineral chrysocolla. ► The chemical bonding of Cu, O and Si has been determined. ► It is concluded that chrysocolla is a mineral in its own right. ► It is not a colloidal mixture of spertiniite and amorphous silica. - Abstract: Selected chrysocolla mineral samples from different origins have been studied by using PXRD, SEM, EDX and XPS. The XRD patterns show that the chrysocolla mineral samples are non-diffracting and no other phases are present in the minerals, thus showing the chrysocolla samples are pure. SEM analyses show the chrysocolla surfaces are featureless. EDX analyses enable the formulae of the chrysocolla samples to be calculated. The thermal decomposition of the mineral chrysocolla has been studied using a combination of thermogravimetric analysis and derivative thermogravimetric analysis. Five thermal decomposition mass loss steps are observed for the chrysocolla from Arizona (a) at 125 °C with the loss of water, (b) at 340 °C with the loss of hydroxyl units, (c) at 468.5 °C with a further loss of hydroxyls, (d) at 821 °C with oxygen loss and (e) at 895 °C with a further loss of oxygen. The thermal analysis of the chrysocolla from Congo shows mass losses at 125, 275.3, 805.6 and 877.4 °C and for the Nevada chrysocolla, mass loss steps at 268, 333, 463, 786.0 and 817.7 °C are observed. The thermal analysis of spertiniite is very different from that of chrysocolla and thermally decomposes at around 160 °C. XPS shows that there are two different copper species present, one which is bonded to oxygen and one to a hydroxyl unit. The O 1s is broad and very symmetrical suggesting two O species of equal number. The bond energy of 102.9 eV for the Si 2p suggests that it is in the form of a silicate. The bond energy is much higher for silicas around ∼103.5 eV. The reported value for silica gel has Si 2p at 103.4 eV. The combination of TG, PXRD, EDX and XPS adds to our fundamental

  5. Attenuated total reflectance-FT-IR spectroscopy for gunshot residue analysis: potential for ammunition determination.

    Science.gov (United States)

    Bueno, Justin; Sikirzhytski, Vitali; Lednev, Igor K

    2013-08-06

    The ability to link a suspect to a particular shooting incident is a principal task for many forensic investigators. Here, we attempt to achieve this goal by analysis of gunshot residue (GSR) through the use of attenuated total reflectance (ATR) Fourier transform infrared spectroscopy (FT-IR) combined with statistical analysis. The firearm discharge process is analogous to a complex chemical process. Therefore, the products of this process (GSR) will vary based upon numerous factors, including the specific combination of the firearm and ammunition which was discharged. Differentiation of FT-IR data, collected from GSR particles originating from three different firearm-ammunition combinations (0.38 in., 0.40 in., and 9 mm calibers), was achieved using projection to latent structures discriminant analysis (PLS-DA). The technique was cross (leave-one-out), both internally and externally, validated. External validation was achieved via assignment (caliber identification) of unknown FT-IR spectra from unknown GSR particles. The results demonstrate great potential for ATR-FT-IR spectroscopic analysis of GSR for forensic purposes.

  6. Antioxidant activity and FT-IR analysis of Datura innoxia and Datura ...

    African Journals Online (AJOL)

    Materials and Methods: Determination of total phenolic content and total flavonoid content and antioxidant activity in terms of total antioxidant assay, ABTS assay, DPPH assay and in-vitro lipid peroxidation inhibiting activity were determined along with the FT-IR (Fourier transform infrared spectroscopy) analysis of the ...

  7. Lithium-ion battery electrolyte emissions analyzed by coupled thermogravimetric/Fourier-transform infrared spectroscopy

    Science.gov (United States)

    Bertilsson, Simon; Larsson, Fredrik; Furlani, Maurizio; Albinsson, Ingvar; Mellander, Bengt-Erik

    2017-10-01

    In the last few years the use of Li-ion batteries has increased rapidly, powering small as well as large applications, from electronic devices to power storage facilities. The Li-ion battery has, however, several safety issues regarding occasional overheating and subsequent thermal runaway. During such episodes, gas emissions from the electrolyte are of special concern because of their toxicity, flammability and the risk for gas explosion. In this work, the emissions from heated typical electrolyte components as well as from commonly used electrolytes are characterized using FT-IR spectroscopy and FT-IR coupled with thermogravimetric (TG) analysis, when heating up to 650 °C. The study includes the solvents EC, PC, DEC, DMC and EA in various single, binary and ternary mixtures with and without the LiPF6 salt, a commercially available electrolyte, (LP71), containing EC, DEC, DMC and LiPF6 as well as extracted electrolyte from a commercial 6.8 Ah Li-ion cell. Upon thermal heating, emissions of organic compounds and of the toxic decomposition products hydrogen fluoride (HF) and phosphoryl fluoride (POF3) were detected. The electrolyte and its components have also been extensively analyzed by means of infrared spectroscopy for identification purposes.

  8. Assessment of a new method for the analysis of decomposition gases of polymers by a combining thermogravimetric solid-phase extraction and thermal desorption gas chromatography mass spectrometry.

    Science.gov (United States)

    Duemichen, E; Braun, U; Senz, R; Fabian, G; Sturm, H

    2014-08-08

    For analysis of the gaseous thermal decomposition products of polymers, the common techniques are thermogravimetry, combined with Fourier transformed infrared spectroscopy (TGA-FTIR) and mass spectrometry (TGA-MS). These methods offer a simple approach to the decomposition mechanism, especially for small decomposition molecules. Complex spectra of gaseous mixtures are very often hard to identify because of overlapping signals. In this paper a new method is described to adsorb the decomposition products during controlled conditions in TGA on solid-phase extraction (SPE) material: twisters. Subsequently the twisters were analysed with thermal desorption gas chromatography mass spectrometry (TDS-GC-MS), which allows the decomposition products to be separated and identified using an MS library. The thermoplastics polyamide 66 (PA 66) and polybutylene terephthalate (PBT) were used as example polymers. The influence of the sample mass and of the purge gas flow during the decomposition process was investigated in TGA. The advantages and limitations of the method were presented in comparison to the common analysis techniques, TGA-FTIR and TGA-MS. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Identification of mineral compositions in some renal calculi by FT Raman and IR spectral analysis

    Science.gov (United States)

    Tonannavar, J.; Deshpande, Gouri; Yenagi, Jayashree; Patil, Siddanagouda B.; Patil, Nikhil A.; Mulimani, B. G.

    2016-02-01

    We present in this paper accurate and reliable Raman and IR spectral identification of mineral constituents in nine samples of renal calculi (kidney stones) removed from patients suffering from nephrolithiasis. The identified mineral components include Calcium Oxalate Monohydrate (COM, whewellite), Calcium Oxalate Dihydrate (COD, weddellite), Magnesium Ammonium Phosphate Hexahydrate (MAPH, struvite), Calcium Hydrogen Phosphate Dihydrate (CHPD, brushite), Pentacalcium Hydroxy Triphosphate (PCHT, hydroxyapatite) and Uric Acid (UA). The identification is based on a satisfactory assignment of all the observed IR and Raman bands (3500-400 cm- 1) to chemical functional groups of mineral components in the samples, aided by spectral analysis of pure materials of COM, MAPH, CHPD and UA. It is found that the eight samples are composed of COM as the common component, the other mineral species as common components are: MAPH in five samples, PCHT in three samples, COD in three samples, UA in three samples and CHPD in two samples. One sample is wholly composed of UA as a single component; this inference is supported by the good agreement between ab initio density functional theoretical spectra and experimental spectral measurements of both sample and pure material. A combined application of Raman and IR techniques has shown that, where the IR is ambiguous, the Raman analysis can differentiate COD from COM and PCHT from MAPH.

  10. Identification of mineral compositions in some renal calculi by FT Raman and IR spectral analysis.

    Science.gov (United States)

    Tonannavar, J; Deshpande, Gouri; Yenagi, Jayashree; Patil, Siddanagouda B; Patil, Nikhil A; Mulimani, B G

    2016-02-05

    We present in this paper accurate and reliable Raman and IR spectral identification of mineral constituents in nine samples of renal calculi (kidney stones) removed from patients suffering from nephrolithiasis. The identified mineral components include Calcium Oxalate Monohydrate (COM, whewellite), Calcium Oxalate Dihydrate (COD, weddellite), Magnesium Ammonium Phosphate Hexahydrate (MAPH, struvite), Calcium Hydrogen Phosphate Dihydrate (CHPD, brushite), Pentacalcium Hydroxy Triphosphate (PCHT, hydroxyapatite) and Uric Acid (UA). The identification is based on a satisfactory assignment of all the observed IR and Raman bands (3500-400c m(-1)) to chemical functional groups of mineral components in the samples, aided by spectral analysis of pure materials of COM, MAPH, CHPD and UA. It is found that the eight samples are composed of COM as the common component, the other mineral species as common components are: MAPH in five samples, PCHT in three samples, COD in three samples, UA in three samples and CHPD in two samples. One sample is wholly composed of UA as a single component; this inference is supported by the good agreement between ab initio density functional theoretical spectra and experimental spectral measurements of both sample and pure material. A combined application of Raman and IR techniques has shown that, where the IR is ambiguous, the Raman analysis can differentiate COD from COM and PCHT from MAPH. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Thermogravimetric analysis, kinetic study, and pyrolysis-GC/MS analysis of 1,1'-azobis-1,2,3-triazole and 4,4'-azobis-1,2,4-triazole.

    Science.gov (United States)

    Jia, Chenhui; Li, Yuchuan; Zhang, Shujuan; Fei, Teng; Pang, Siping

    2018-03-01

    In general, the greater the number of directly linked nitrogen atoms in a molecule, the better its energetic performance, while the stability will be accordingly lower. But 1,1'-azobis-1,2,3-triazole (1) and 4,4'-azobis-1,2,4-triazole (2) show remarkable properties, such as high enthalpies of formation, high melting points, and relatively high stabilities. In order to rationalize this unexpected behavior of the two compounds, it is necessary to study their thermal decompositions and pyrolyses. Although a great deal of research has been focused on the synthesis and characterization of energetic materials with 1 and 2 as the backbone, a complete report on their fundamental thermodynamic parameters and thermal decomposition properties has not been published. Thermogravimetric-differential scanning calorimetry were used to obtain the thermal decomposition data of the title compounds. Kissinger and Ozawa-Doyle methods, the two selected non-isothermal methods, are presented for analysis of the solid-state kinetic data. Pyrolysis-gas chromatography/mass spectrometry was used to study the pyrolysis process of the title compounds. The DSC curves show that the thermal decompositions of 1 and 2 are at different heating rates involved a single exothermic process. The TG curves provide insight into the total weight losses from the compounds associated with this process. At different pyrolysis temperatures, the compositions and types of the pyrolysis products differ greatly and the pyrolysis reaction at 500 °C is more thorough than 400 °C. Apparent activation energies (E) and pre-exponential factors (lnA/s -1 ) are 291.4 kJ mol -1 and 75.53 for 1; 396.2 kJ mol -1 and 80.98 for 2 (Kissinger). The values of E are 284.5 kJ mol -1 for 1 and 386.1 kJ mol -1 for 2 (Ozawa-Doyle). The critical temperature of thermal explosion (T b ) is evaluated as 187.01 °C for 1 and 282.78 °C for 2. The title compounds were broken into small fragment ions under the pyrolysis conditions

  12. Characterization of thermal reaction of aluminum/copper (II) oxide/poly(tetrafluoroethene) nanocomposite by thermogravimetric analysis, differential scanning calorimetry, mass spectrometry and X-ray diffraction

    International Nuclear Information System (INIS)

    Li, Xiangyu; Yang, Hongtao; Li, Yan-chun

    2015-01-01

    Highlights: • The thermal reaction properties of the Al/CuO/PTFE nanocomposite were investigated. • The Al/PTFE and CuO/PTFE nanocomposites were prepared and tested for comparison. • TG/DSC–MS and XRD analysis were performed. • PTFE is oxidizing Al and reducing CuO during the thermal decomposition. - Abstract: The application of fluoropolymers as reactive agent in energetic materials have attracted significant interest recently. In this study, the thermal reaction properties of the aluminum nanoparticles/copper (II) oxide nanoparticles/poly(tetrafluoroethene) (Al-NPs/CuO-NPs/PTFE) nanocomposite (mass ratio of Al-NPs/CuO-NPs/PTFE = 20/60/20) were investigated by means of thermogravimetry/differential scanning calorimetry–mass spectrometry (TG/DSC–MS) and X-ray diffraction (XRD) analyses. The Al-NPs/PTFE (mass ratio of Al-NPs/PTFE = 50/50) and CuO-NPs/PTFE (mass ratio of CuO-NPs/PTFE = 75/25) nanocomposites were also prepared and tested for comparison. It is observed that PTFE is acting as both oxidizer and reducer during the thermal decomposition process of Al-NPs/CuO-NPs/PTFE nanocomposites. Before 615 °C, PTFE is oxidized by CuO-NPs and oxidizing Al-NPs, resulting mass reduction. After 615 °C, the excessive aluminum and copper (I)/copper (II) oxide will proceed the exothermic condensed phase reaction.

  13. An in situ FTIR spectroscopic and thermogravimetric analysis study of the dehydration and dihydroxylation of SnO2: the contribution of the (100), (110) and (111) facets.

    Science.gov (United States)

    Christensen, P A; Attidekou, P S; Egdell, R G; Maneelok, S; Manning, D A C

    2016-08-17

    Nanoparticulate SnO2 produced by a hydrothermal method was characterised by BET, XRD, TGA-MS and in situ variable temperature diffuse reflectance infra red spectroscopy (DRIFTS) to determine the surface behaviour of water. For the (100) facets, hydrogen bonding does not occur, and water adsorption is less strong than for the (111) and (110) facets where hydrogen bonding does occur. Reversible uptake of oxygen was observed. These findings have implications for other surface-gas reactions in which Ni and Sb co-doped SnO2 (NATO) anodes are used for ozone generation. BET showed the relatively high surface area and nanometer scale of the SnO2 particles, whilst XRD confirmed the nano dimension of the crystallites and showed only the cassiterite phase. TGA analysis indicated four temperature regions over which mass loss was observed. These and the in situ DRIFTS studies revealed the existence of various forms of water associated with specific crystal facets of the SnO2, as well as the existence of isolated O-H groups and adsorbed oxygen species. Electronic absorptions were also observed and the data rationalised in terms of the existence of both free electron absorptions, and absorptions from oxygen vacancy states. The role of adsorbed molecular oxygen in electrochemical ozone generation at Ni and Sb co-doped SnO2 (NATO) anodes was strongly suggested by this work.

  14. Study of solid chemical evolution in torrefaction of different biomasses through solid-state "1"3C cross-polarization/magic angle spinning NMR (nuclear magnetic resonance) and TGA (thermogravimetric analysis)

    International Nuclear Information System (INIS)

    Rodriguez Alonso, Elvira; Dupont, Capucine; Heux, Laurent; Da Silva Perez, Denilson; Commandre, Jean-Michel; Gourdon, Christophe

    2016-01-01

    The objective of this work is to compare mass loss and chemical evolution of the solid phase, versus time, during dynamic torrefaction of different types of biomass. For this purpose, two experiments, ThermoGravimetric Analysis and solid-state "1"3C Cross-Polarization/Magic Angle Spinning Nuclear Magnetic Resonance, were run on four representative biomasses. Overall mass loss and chemical evolution of the solid phase were followed, respectively, as a function of temperature and time. Thanks to this coupled information, it was shown that the knowledge of both solid mass loss and chemical evolution is necessary to characterize torrefaction severity. Moreover, biomasses containing higher proportions of xylan lost mass faster than those containing lower proportions. Lignin showed a protecting role towards cellulose, which would lead to a faster degradation of non-woody biomasses in comparison with woody biomasses. Three parameters would have an influence on solid chemical evolution during torrefaction: xylan content in hemicellulose, lignin content in biomass, and cellulose crystallinity. - Highlights: • Torrefaction of four biomasses was studied with TGA and solid-state NMR. • Both solid mass loss and chemical evolution characterize torrefaction severity. • Biomasses containing a higher proportion of xylan lose mass faster. • Lignin shows a stronger protecting role in degradation of woody biomasses. • Xylan, lignin and crystalline cellulose values influence solid chemical evolution.

  15. Application of FT-IR spectroscopy on breast cancer serum analysis

    Science.gov (United States)

    Elmi, Fatemeh; Movaghar, Afshin Fayyaz; Elmi, Maryam Mitra; Alinezhad, Heshmatollah; Nikbakhsh, Novin

    2017-12-01

    Breast cancer is regarded as the most malignant tumor among women throughout the world. Therefore, early detection and proper diagnostic methods have been known to help save women's lives. Fourier Transform Infrared (FT-IR) spectroscopy, coupled with PCA-LDA analysis, is a new technique to investigate the characteristics of serum in breast cancer. In this study, 43 breast cancer and 43 healthy serum samples were collected, and the FT-IR spectra were recorded for each one. Then, PCA analysis and linear discriminant analysis (LDA) were used to analyze the spectral data. The results showed that there were differences between the spectra of the two groups. Discriminating wavenumbers were associated with several spectral differences over the 950-1200 cm- 1(sugar), 1190-1350 cm- 1 (collagen), 1475-1710 cm- 1 (protein), 1710-1760 cm- 1 (ester), 2800-3000 cm- 1 (stretching motions of -CH2 & -CH3), and 3090-3700 cm- 1 (NH stretching) regions. PCA-LDA performance on serum IR could recognize changes between the control and the breast cancer cases. The diagnostic accuracy, sensitivity, and specificity of PCA-LDA analysis for 3000-3600 cm- 1 (NH stretching) were found to be 83%, 84%, 74% for the control and 80%, 76%, 72% for the breast cancer cases, respectively. The results showed that the major spectral differences between the two groups were related to the differences in protein conformation in serum samples. It can be concluded that FT-IR spectroscopy, together with multivariate data analysis, is able to discriminate between breast cancer and healthy serum samples.

  16. Thermogravimetric assessment of thermal degradation in asphaltenes

    Energy Technology Data Exchange (ETDEWEB)

    Barneto, Agustín García, E-mail: agustin.garcia@diq.uhu.es [Department of Chemical Engineering, Physical Chemistry and Organic Chemistry, University of Huelva, Huelva (Spain); Carmona, José Ariza [Department of Chemical Engineering, Physical Chemistry and Organic Chemistry, University of Huelva, Huelva (Spain); Garrido, María José Franco [CEPSA, RDI Centre, Madrid (Spain)

    2016-03-20

    Graphical abstract: - Highlights: • Asphaltenes content of visbreaking streams in oil refinery can be measured by using TGA. • Deconvoluting TGA curves allows the thermal-based composition of asphaltenes to be elucidated. • Asphaltenes cracking involves acceleratory stages compatible with autocatalytic kinetic. • Activation energy during asphaltenes pyrolysis increased with increasing temperature. • Activation energy remained almost constant at 200–225 kJ/mol during oxidative cracking. - Abstract: Monitoring asphaltenes is very important with a view to optimizing visbreaking units in oil refineries. Current analyses based on selective dissolution in different solvents are slow, so new, more expeditious methods for measuring asphaltenes are required to facilitate fuel-oil production. In this work, we studied the thermal degradation of asphaltenes as the potential basis for a thermogravimetric method for their monitoring in visbreaking streams. The thermal degradation of asphaltenes occurs largely from 400 to 500 °C; the process is quite smooth in an inert environment but involves several fast mass loss events in the air. Kinetic parameters for characterizing the process were determined by using two model-free methods and the modified Prout–Tompkins kinetic equation to examine asphaltene thermolysis. Both types of methods showed the activation energy to increase during pyrolysis but to remain almost constant during cracking in the presence of oxygen or even diminish during char oxidation. Deconvoluting the thermogravimetric profiles revealed that asphaltene thermolysis in the air cannot be accurately described in terms of an nth order kinetic model because it involves some acceleratory phases. Also, thermogravimetric analyses of visbreaking streams revealed that char production in them is proportional to their asphaltene content. This relationship enables the thermogravimetric measurement of asphaltenes.

  17. Thermogravimetric assessment of thermal degradation in asphaltenes

    International Nuclear Information System (INIS)

    Barneto, Agustín García; Carmona, José Ariza; Garrido, María José Franco

    2016-01-01

    Graphical abstract: - Highlights: • Asphaltenes content of visbreaking streams in oil refinery can be measured by using TGA. • Deconvoluting TGA curves allows the thermal-based composition of asphaltenes to be elucidated. • Asphaltenes cracking involves acceleratory stages compatible with autocatalytic kinetic. • Activation energy during asphaltenes pyrolysis increased with increasing temperature. • Activation energy remained almost constant at 200–225 kJ/mol during oxidative cracking. - Abstract: Monitoring asphaltenes is very important with a view to optimizing visbreaking units in oil refineries. Current analyses based on selective dissolution in different solvents are slow, so new, more expeditious methods for measuring asphaltenes are required to facilitate fuel-oil production. In this work, we studied the thermal degradation of asphaltenes as the potential basis for a thermogravimetric method for their monitoring in visbreaking streams. The thermal degradation of asphaltenes occurs largely from 400 to 500 °C; the process is quite smooth in an inert environment but involves several fast mass loss events in the air. Kinetic parameters for characterizing the process were determined by using two model-free methods and the modified Prout–Tompkins kinetic equation to examine asphaltene thermolysis. Both types of methods showed the activation energy to increase during pyrolysis but to remain almost constant during cracking in the presence of oxygen or even diminish during char oxidation. Deconvoluting the thermogravimetric profiles revealed that asphaltene thermolysis in the air cannot be accurately described in terms of an nth order kinetic model because it involves some acceleratory phases. Also, thermogravimetric analyses of visbreaking streams revealed that char production in them is proportional to their asphaltene content. This relationship enables the thermogravimetric measurement of asphaltenes.

  18. Thermogravimetric analysis of combustible waste components

    DEFF Research Database (Denmark)

    Munther, Anette; Wu, Hao; Glarborg, Peter

    In order to gain fundamental knowledge about the co-combustion of coal and waste derived fuels, the pyrolytic behaviors of coal, four typical waste components and their mixtures have been studied by a simultaneous thermal analyzer (STA). The investigated waste components were wood, paper, polypro......In order to gain fundamental knowledge about the co-combustion of coal and waste derived fuels, the pyrolytic behaviors of coal, four typical waste components and their mixtures have been studied by a simultaneous thermal analyzer (STA). The investigated waste components were wood, paper...

  19. The first photometric analysis of the near contact binary IR Cas

    International Nuclear Information System (INIS)

    Li, Kai; Hu, S.-M.; Guo, D.-F.; Jiang, Y.-G.; Gao, D.-Y.; Chen, X.

    2014-01-01

    The first photometric analysis of IR Cas was carried out based on the new observed BVRI light curves. The symmetric light curves and nearly flat secondary minimum indicate that very precise photometric results can be determined. We found that IR Cas is a near contact binary with the primary component filling its Roche lobe. An analysis of the O – C diagram based on all available times of minimum light reveals evidence for a periodic change with a semi-amplitude of 0.0153 days and a period of 39.7 yr superimposed on a secular decrease at a rate of dp/dt = –1.28(± 0.09) × 10 –7 days yr –1 . The most reasonable explanation for the periodic change is the light time-travel effect due to a third body. The period decrease may be caused by mass transfer from the primary component to the secondary. With the decreasing period, IR Cas would eventually evolve into a contact system.

  20. A Combined Variable-Temperature Neutron Diffraction and Thermogravimetric Analysis Study on a Promising Oxygen Electrode, SrCo0.9Nb0.1O3-δ, for Reversible Solid Oxide Fuel Cells.

    Science.gov (United States)

    Yang, Tianrang; Wang, Jie; Chen, Yan; An, Ke; Ma, Dong; Vogt, Thomas; Huang, Kevin

    2017-10-11

    The present study investigates the temperature-structure-stoichiometry relationship of a promising oxygen electrode SrCo 0.9 Nb 0.1 O 3-δ over a temperature (T) range from room temperature (RT) to 900 °C. The techniques employed are variable-temperature neutron diffraction (VTND) and thermogravimetric analysis (TGA). At T < 75 °C, VTND reveals a tetragonal (P4/mmm) structure with a G-type magnetic ordering. Above 75 °C, the nucleus structure remains the same, while the magnetic ordering disappears. A phase transition from tetragonal (P4/mmm) to cubic (Pm3̅m) is observed at 412 °C, where the two Co sites and three O sites in the P4/mmm phase converge to one equivalent site, respectively. The phase transition temperature coincides with the peak temperature of oxygen uptake obtained by TGA. It is also observed that the Nb dopant has no preferred Co site to occupy. The oxygen vacancies are mostly located at the O3 site surrounding the Co2 site in the P4/mmm structure. The intermediate-spin state of Co 3+ at the Co2 site is responsible for the observed distortions of CoO 6 octahedra, i.e., elongation of Co2O 6 octahedra and shortening of Co1O 6 octahedra along the c-axis, which is a phenomenon known as Jahn-Teller distortion. At high temperatures, large thermal displacement factor for O 2- is observed with high concentration of oxygen vacancies, providing a structural environment favorable to high O 2- conductivity in Nb-doped SrCoO 3 -based oxygen electrode materials.

  1. Surface area and pore size characteristics of nanoporous gold subjected to thermal, mechanical, or surface modification studied using gas adsorption isotherms, cyclic voltammetry, thermogravimetric analysis, and scanning electron microscopy

    Science.gov (United States)

    Tan, Yih Horng; Davis, Jason A.; Fujikawa, Kohki; Ganesh, N. Vijaya; Demchenko, Alexei V.

    2012-01-01

    Nitrogen adsorption/desorption isotherms are used to investigate the Brunauer, Emmett, and Teller (BET) surface area and Barrett-Joyner-Halenda (BJH) pore size distribution of physically modified, thermally annealed, and octadecanethiol functionalized np-Au monoliths. We present the full adsorption-desorption isotherms for N2 gas on np-Au, and observe type IV isotherms and type H1 hysteresis loops. The evolution of the np-Au under various thermal annealing treatments was examined using scanning electron microscopy (SEM). The images of both the exterior and interior of the thermally annealed np-Au show that the porosity of all free standing np-Au structures decreases as the heat treatment temperature increases. The modification of the np-Au surface with a self-assembled monolayer (SAM) of C18-SH (coverage of 2.94 × 1014 molecules cm−2 based from the decomposition of the C18-SH using thermogravimetric analysis (TGA)), was found to reduce the strength of the interaction of nitrogen gas with the np-Au surface, as reflected by a decrease in the ‘C’ parameter of the BET equation. From cyclic voltammetry studies, we found that the surface area of the np-Au monoliths annealed at elevated temperatures followed the same trend with annealing temperature as found in the BET surface area study and SEM morphology characterization. The study highlights the ability to control free-standing nanoporous gold monoliths with high surface area, and well-defined, tunable pore morphology. PMID:22822294

  2. Miniature quartz crystal-resonator-based thermogravimetric detector.

    Science.gov (United States)

    Sai, N; Tagawa, Y; Sohgawa, M; Abe, T

    2014-09-01

    In this work, a new design for a microheater combined with a quartz crystal microbalance (QCM) array for thermogravimetric analysis is presented. Each QCM consists of two electrodes to excite thickness-shear-mode vibrations and one microheater to increase the temperature on the crystal backside. In addition, all the electrode pads are patterned on the crystal backside, making the design of the QCM compact and user-friendly. Finally, the proposed QCM array was employed to separate ethanol from methanol. This was successfully achieved via thermal desorption spectra calculated by differentiating the frequency changes.

  3. An assessment of surface emissivity variation effects on plasma uniformity analysis using IR cameras

    Science.gov (United States)

    Greenhalgh, Abigail; Showers, Melissa; Biewer, Theodore

    2017-10-01

    The Prototype-Material Plasma Exposure eXperiment (Proto-MPEX) is a linear plasma device operating at Oak Ridge National Laboratory (ORNL). Its purpose is to test plasma source and heating concepts for the planned Material Plasma Exposure eXperiment (MPEX), which has the mission to test the plasma-material interactions under fusion reactor conditions. In this device material targets will be exposed to high heat fluxes (>10 MW/m2). To characterize the heat fluxes to the target a IR thermography system is used taking up to 432 frames per second videos. The data is analyzed to determine the surface temperature on the target in specific regions of interest. The IR analysis has indicated a low level of plasma uniformity; the plasma often deposits more heat to the edge of the plate than the center. An essential parameter for IR temperature calculation is the surface emissivity of the plate (stainless steel). A study has been performed to characterize the variation in the surface emissivity of the plate as its temperature changes and its surface finish is modified by plasma exposure.

  4. MicrOmega IR: a new infrared hyperspectral imaging microscope or in situ analysis

    Science.gov (United States)

    Vaitua, Leroi; Bibring, Jean-Pierre; Berthé, Michel

    2017-11-01

    MicrOmega IR is an ultra miniaturized Near Infrared hyperspectral microscope for in situ analysis of samples. It is designed to be implemented on board space planetary vehicles (lander and/or rovers). It acquires images of samples typically some 5 mm in width with a spatial sampling of 20 μm. On each pixel, MicrOmega acquires the spectrum in the spectral range 0.9 - 2.6 μm, with a possibility to extend the sensibility up to 4 μm. The spectrum will be measured in up to 300 contiguous spectral channels (600 in the extended range): given the diagnostic spectral features present in this domain, it provides the composition of each spatially resolved constituent. MicrOmega has thus the potential to identify: minerals, such as pyroxene and olivine, ferric oxides, hydrated phases such as phyllosilicates, sulfates and carbonates, ices and organics. The composition of the various phases within a given sample is a critical record of its formation and evolution. Coupled to the mapping information, it provides unique clues to describe the history of the parent body. In particular, the capability to identify hydrated grains and to characterize their adjacent phases has a huge potential in the search for potential bio-relics in Martian samples. This purely non destructive characterization enables further analyses (e.g. through mass spectrometry) to be performed, and/or to contribute to sample selection to return to Earth. MicrOmega IR is coupled to a visible microscope: MicrOmega VIS. Thus, the MicrOmega instrument is developed by an international consortium: IAS (Orsay, France), LESIA (Meudon, France), CBM (Orléans, France), University Of Bern (Bern, Switzerland), IKI (Moscow, Russia). This instrument (MicrOmega IR, MicrOmega VIS and the electronics) is selected for the ESA Exomars mission (launch scheduled for 2013). MicrOmega IR will be used in a reduced spectral range (0.9 - 2.6 μm), due to power, mass and thermal constraints: however, most minerals and other

  5. Análise termogravimétrica do óleo essencial de pimenta longa (Piper hispidinervium C. DC Thermogravimetric analysis of long pepper (Piper hispidinervium C.DC. essential oil

    Directory of Open Access Journals (Sweden)

    Marco Aurelio Cremasco

    2011-01-01

    Full Text Available A pimenta longa (Piper hispidinervium C. DC. é um arbusto originário da região amazônica, cujo óleo essencial é rico em safrol. O óleo essencial da pimenta longa é comercializado in natura, o que faz o processamento para a obtenção do safrol elemento fundamental de investigação científica e tecnológica. Uma importante etapa para a obtenção do safrol é a definição da estratégia da sua separação do óleo essencial a partir, por exemplo, da destilação. Neste caso, torna-se essencial o conhecimento de parâmetros termodinâmicos, tais como energia de ativação e calor latente de vaporização. Neste trabalho é utilizada a técnica termogravimétrica para a obtenção dos valores da energia de ativação e calor latente de vaporização do óleo essencial de P. hispidinervium. O processo de evaporação do óleo essencial obedece à cinética de ordem zero, resultando para a energia de ativação e calor latente de vaporização os valores 42,11 kJ.mol-1 e 43,73 kJ.mol-1, respectivamente.Long pepper (Piper hispidinervium C. DC. is a shrub found in the Amazon region, which supplies an essential oil rich in safrole. Normally, long pepper essential oil is commercialized in natura, which makes its processing a fundamental step in scientific and technological investigation. An important step of safrole commercialization is the separation of essential oil by, for example, a distillation process. In such a case it is important to know some thermodynamics parameters, such as energy of activation and enthalpy of vaporization. The present study was aimed at applying the kinetic of zero order evaporation process for the essential oil of P. hispidinervum by thermogravimetric analysis. The thermal analysis data were utilized to determine the energy of activation and enthalpy of vaporization, which resulted in the values 41.11 kJ.mol-1 and 43.73 kJ.mol-1, respectively.

  6. Synthesis, thermogravimetric, spectroscopic and theoretical characterization of copper(II) complex with 4-chloro-2-nitrobenzenosulfonamide

    Science.gov (United States)

    Camí, G.; Chacón Villalba, E.; Di Santi, Y.; Colinas, P.; Estiu, G.; Soria, D. B.

    2011-05-01

    4-Chloro-2-nitrobenzenesulfonamide (ClNbsa) was purified and characterized. A new copper(II) complex, [Cu(ClNbsa) 2(NH 3) 2], has been prepared using the sulfonamide as ligand. The thermal behavior of both, the ligand and the Cu(II) complex, was investigated by thermogravimetric analyses (TG) and differential thermal analysis (DT), and the electronic characteristics analyzed by UV-VIS, FTIR, Raman and 1H NMR spectroscopies. The experimental IR, Raman and UV-VIS spectra have been assigned on the basis of DFT calculations at the B3LYP level of theory using the standard (6-31 + G ∗∗) basis set. The geometries have been fully optimized in vacuum and in modeled dimethylsulfoxide (DMSO) solvent, using for the latter a continuum solvation model that reproduced the experimental conditions of the UV-VIS spectroscopy. The theoretical results converged to stable conformations for the free sulfonamide and for the complex, suggesting for the latter a distorted square planar geometry in both environments.

  7. Thermogravimetric research of hydrogen storage materials

    International Nuclear Information System (INIS)

    Kleperis, J; Grinberga, L; Ergle, M; Chikvaidze, G; Klavins, J

    2007-01-01

    During thermogravimetric research of metal hydrides we noticed mass growth of samples above 200 deg. C even in an argon atmosphere. Further heating is leading to the growth of weight up to 2-7 weight% till 500 0 C. Second run of the same sample without taking out of DTA instrument gave only small mass changes, indicating that noticed mass increase during first run is permanent. Microscope and elemental analyses were made to determine the reason of mass growth. XRD inspection revealed the formation of new phase with bunsenite NiO structure with deformed cubic structure. The new phase is no more active to hydrogen sorption/desorption. Our results demonstrated that the usage of hydrogen storage alloys AB 5 must be taken with care - it is important not to exceed some critical temperature were irreversible structural, compositional and morphological changes will occur

  8. Thermogravimetric studies of New Zealand coals

    Energy Technology Data Exchange (ETDEWEB)

    Beamish, B.B.; Rodgers, K.A.; Benfell, K.E.; Shaw, K.J. [University of Auckland, Auckland (New Zealand). Dept. of Geology

    1997-12-31

    The thermal behaviour of New Zealand coals may be reliably characterised by a series of tightly constrained thermogravimetric (TG) procedures of high repeatability developed in the Department of Geology at The University of Auckland. Proximate, combustion and char reactivity analyses can be routinely obtained for run-of-mine samples. Volatile matter determination by TG produces an acceptable reproducible result compared with the ISO method, whereas further refinement of the technique is necessary to achieve the same level of precision for ash content of New Zealand low rank coals. Combining combustion and char reactivity analyses enables the performance of a coal to be assessed under differing operating conditions, and offers the opportunity to elucidate competing effects of major element geochemistry of the coal. 12 refs., 4 figs., 2 tabs.

  9. Ames S-32 O-16 O-18 Line List for High-Resolution Experimental IR Analysis

    Science.gov (United States)

    Huang, Xinchuan; Schwenke, David W.; Lee, Timothy J.

    2016-01-01

    By comparing to the most recent experimental data and spectra of the SO2 628 ?1/?3 bands (see Ulenikov et al., JQSRT 168 (2016) 29-39), this study illustrates the reliability and accuracy of the Ames-296K SO2 line list, which is accurate enough to facilitate such high-resolution spectroscopic analysis. The SO2 628 IR line list is computed on a recently improved potential energy surface (PES) refinement, denoted Ames-Pre2, and the published purely ab initio CCSD(T)/aug-cc-pVQZ dipole moment surface. Progress has been made in both energy level convergence and rovibrational quantum number assignments agreeing with laboratory analysis models. The accuracy of the computed 628 energy levels and line list is similar to what has been achieved and reported for SO2 626 and 646, i.e. 0.01-0.03 cm(exp -1) for bands up to 5500 cm(exp -1). During the comparison, we found some discrepancies in addition to overall good agreements. The three-IR-list based feature-by-feature analysis in a 0.25 cm(exp -1) spectral window clearly demonstrates the power of the current Ames line lists with new assignments, correction of some errors, and intensity contributions from varied sources including other isotopologues. We are inclined to attribute part of detected discrepancies to an incomplete experimental analysis and missing intensity in the model. With complete line position, intensity, and rovibrational quantum numbers determined at 296 K, spectroscopic analysis is significantly facilitated especially for a spectral range exhibiting such an unusually high density of lines. The computed 628 rovibrational levels and line list are accurate enough to provide alternatives for the missing bands or suspicious assignments, as well as helpful to identify these isotopologues in various celestial environments. The next step will be to revisit the SO2 828 and 646 spectral analyses.

  10. THERMOGRAVIMETRIC INVESTIGATIONS OF VAGINAL SUPPOSITORY WITH THYME OIL

    Directory of Open Access Journals (Sweden)

    N. V. Melnikova

    2015-04-01

    Full Text Available One of the main stages in new medicines creation is the development of their making technology. Technological process of suppository making includes ratherlongthermal treatment during preparation and homogenization of suppository base, active substancesaddition. These factors create danger of chemical and physical transformation of active substances and excipients in suppository up to their destruction and change of pharmacological and physical-chemical properties. Use of thermogravimetric analysis in pharmaceutical technology allows to studythepossibility of chemical interaction in dosage forms over the wide temperature range. The aim of this work is study of thermal treatmenteffects of suppository base with thyme oil over the temperature range of suppository manufacturing. Methods and results. As an object of thermogravimetric study vaginal suppository with thyme oil 0,2 g, suppository-placebo containing propylenglycol, polyethylene glycol 400, proxanol 268, twin 80 and the active ingredient of «Царствоароматов», Ukraine, production were used. Thermogravimetric analysis was carried out on the derivatograph«Shimadzu DTG-60», Japan, with the platinum and platinum-rhodiumthermopair with samples heating in aluminiumcrucibles from 25 to 200ºС. As standard α-Al2O3was used.Heating rate was 10ºСper min.Mass of the samples was 23,45– 39,63 mg. Obtained data were registered by the derivatograph as curves T, DTA, TGA. The T curve on the derivatogramm shows the temperature change and the TGA curve demonstrates the sample mass change during investigation. The DTA curve reflects differentiation of thermal effects and contains information about endothermic and exothermal maximum and is used for qualitative valuation of derivatogramm. According to results of thermogravimetric investigation the thyme oil is thermostable substance which is gradually evaporating during heating. So, at the beginning of study the test sample mass was 23

  11. Spectroscopic, thermogravimetric and structural characterization analyses for comparing Municipal Solid Waste composts and vermicomposts stability and maturity.

    Science.gov (United States)

    Soobhany, Nuhaa; Gunasee, Sanjana; Rago, Yogeshwari Pooja; Joyram, Hashita; Raghoo, Pravesh; Mohee, Romeela; Garg, Vinod Kumar

    2017-07-01

    This is the first-ever study of its kind for an extensive assessment and comparison of maturity indexes between compost and vermicompost that have been derived from Municipal Solid Waste (MSW). The spectroscopic (Fourier transform infrared spectroscopy: FT-IR), thermogravimetric analysis (TG), differential scanning calorimetry (DSC) and structural characterization (scanning electron microscope: SEM) were recorded. FT-IR spectra showed an increase in conversion of polysaccharides species and aliphatic methylene groups in vermicompost compared to compost as depicted from the variation of the intensity of the peaks. TG curves of final vermicompost showed a much lower mass loss when compared to compost, indicating higher stability in feedstock. SEM micrographs of the vermicompost reflected strong fragmentation of material than composts which revealed the extent of intra-structural degradation of MSW. These findings elucidate on a clear comparison between composts and vermicomposts in terms of maturity indexes for soil enhancement and in agriculture as organic fertilizer. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. FT-IR microscopical analysis with synchrotron radiation: The microscope optics and system performance

    International Nuclear Information System (INIS)

    Reffner, J.A.; Martoglio, P.A.; Williams, G.P.

    1995-01-01

    When a Fourier transform infrared (FT-IR) microspectrometer was first interfaced with the National Synchrotron Light Source (NSLS) in September 1993, there was an instant realization that the performance at the diffraction limit had increased 40-100 times. The synchrotron source transformed the IR microspectrometer into a true IR microprobe, providing high-quality IR spectra for probe diameters at the diffraction limit. The combination of IR microspectroscopy and synchrotron radiation provides a powerful new tool for molecular spectroscopy. The ability to perform IR microspectroscopy with synchrotron radiation is still under development at Brookhaven National Laboratory, but several initial studies have been completed that demonstrate the broad-ranging applications of this technology and its potential for materials characterization

  13. FT-IR microscopical analysis with synchrotron radiation: The microscope optics and system performance

    Energy Technology Data Exchange (ETDEWEB)

    Reffner, J.A.; Martoglio, P.A. [Spectra-Tech, Inc., Shelton, CT (United States); Williams, G.P. [Brookhaven National Lab., Upton, NY (United States)

    1995-01-01

    When a Fourier transform infrared (FT-IR) microspectrometer was first interfaced with the National Synchrotron Light Source (NSLS) in September 1993, there was an instant realization that the performance at the diffraction limit had increased 40-100 times. The synchrotron source transformed the IR microspectrometer into a true IR microprobe, providing high-quality IR spectra for probe diameters at the diffraction limit. The combination of IR microspectroscopy and synchrotron radiation provides a powerful new tool for molecular spectroscopy. The ability to perform IR microspectroscopy with synchrotron radiation is still under development at Brookhaven National Laboratory, but several initial studies have been completed that demonstrate the broad-ranging applications of this technology and its potential for materials characterization.

  14. Quantitative analysis of semivolatile organic compounds in selected fractions of air sample extracts by GC/MI-IR spectrometry

    International Nuclear Information System (INIS)

    Childers, J.W.; Wilson, N.K.; Barbour, R.K.

    1990-01-01

    The authors are currently investigating the capabilities of gas chromatography/matrix isolation infrared (GC/MI-IR) spectrometry for the determination of semivolatile organic compounds (SVOCs) in environmental air sample extracts. Their efforts are focused on the determination of SVOCs such as alkylbenzene positional isomers, which are difficult to separate chromatographically and to distinguish by conventional electron-impact ionization GC/mass spectrometry. They have performed a series of systematic experiments to identify sources of error in quantitative GC/MI-IR analyses. These experiments were designed to distinguish between errors due to instrument design or performance and errors that arise from some characteristic inherent to the GC/MI-IR technique, such as matrix effects. They have investigated repeatability as a function of several aspects of GC/MI IR spectrometry, including sample injection, spectral acquisition, cryogenic disk movement, and matrix deposition. The precision, linearity, dynamic range, and detection limits of a commercial GC/MI-IR system for target SVOCs were determined and compared to those obtained with the system's flame ionization detector. The use of deuterated internal standards in the quantitative GC/MI-IR analysis of selected fractions of ambient air sample extracts will be demonstrated. They will also discuss the current limitations of the technique in quantitative analyses and suggest improvements for future consideration

  15. Catalytic thermal decomposition of polyethylene determined by thermogravimetric treatment

    International Nuclear Information System (INIS)

    Nisar, J.; Khan, M.S.; Khan, M.A.

    2014-01-01

    In this study low density polyethylene (LDPE) has been studied by thermogravimetric analysis (TGA) using commercially available oxides as catalysts. TGA experiments were used to evaluate the activity of different catalysts on low density polyethylene (LDPE) degradation and to study the effect in terms of type and amount of catalyst used. All the catalysts used improved the pyrolysis of LDPE. The reaction rates were found to increase with increase in amount of catalyst. Among the catalysts used, alumina acidic active catalyst performed better at all four fractions. Moreover, alumina acidic active reduced weight loss temperature better than others tested catalysts. The effect of alumina neutral catalyst on the pyrolysis of LDPE is less pronounced due to its small surface area and pore size. The effect of these catalysts showed that surface area, number of acidic sites and pore size were found as the key factors for the energy efficient degradation of polymers. (author)

  16. Molecular structure, vibrational analysis (IR and Raman) and quantum chemical investigations of 1-aminoisoquinoline

    Science.gov (United States)

    Sivaprakash, S.; Prakash, S.; Mohan, S.; Jose, Sujin P.

    2017-12-01

    Quantum chemical calculations of energy and geometrical parameters of 1-aminoisoquinoline [1-AIQ] were carried out by using DFT/B3LYP method using 6-311G (d,p), 6-311G++(d,p) and cc-pVTZ basis sets. The vibrational wavenumbers were computed for the energetically most stable, optimized geometry. The vibrational assignments were performed on the basis of potential energy distribution (PED) using VEDA program. The NBO analysis was done to investigate the intra molecular charge transfer of the molecule. The frontier molecular orbital (FMO) analysis was carried out and the chemical reactivity descriptors of the molecule were studied. The Mulliken charge analysis, molecular electrostatic potential (MEP), HOMO-LUMO energy gap and the related properties were also investigated at B3LYP level. The absorption spectrum of the molecule was studied from UV-Visible analysis by using time-dependent density functional theory (TD-DFT). Fourier Transform Infrared spectrum (FT-IR) and Raman spectrum of 1-AIQ compound were analyzed and recorded in the range 4000-400 cm-1 and 3500-100 cm-1 respectively. The experimentally determined wavenumbers were compared with those calculated theoretically and they complement each other.

  17. Advances in analysis of pre-earthquake thermal anomalies by analyzing IR satellite data

    Science.gov (United States)

    Ouzounov, D.; Bryant, N.; Filizzola, C.; Pergola, N.; Taylor, P.; Tramutoli, V.

    Presented work addresses the possible relationship between tectonic stress, electro-chemical and thermodynamic processes in the atmosphere and increasing infrared (IR) flux as part of a larger family of electromagnetic (EM) phenomena related to earthquake activity. Thermal infra-red (TIR) surveys performed by polar orbiting (NOAA/AVHRR, MODIS) and geosynchronous weather satellites (GOES, METEOSAT) seems to indicate the appearance (from days to weeks before the event) of "anomalous" space-time TIR transients associated with the place (epicentral area, linear structures and fault systems) and the time of occurrence of a number of major earthquakes with M>5 and focal depths no deeper than 50km. As Earth emitted in 8-14 microns range the TIR signal measured from satellite strongly vary depending on meteorological conditions and other factors (space-time changes in atmospheric transmittance, time/season, solar and satellite zenithal angles and etc) independent from seismic activity, a preliminary definition of "anomalous TIR signal" should be given. To provide reliable discrimination of thermal anomalous area from the natural events (seasonal changes, local morphology) new robust approach (RAT) has been recently proposed (and successfully applied in the field of the monitoring of the major environmental risks) that permits to give a statistically based definition of thermal info-red (TIR) anomaly and reduce of false events detection. New techniques also were specifically developed to assure the precise co-registration of all satellite scenes and permit accurate time-series analysis of satellite observations. As final results we present examples of most recent 2000/2004 worldwide strong earthquakes and the techniques used to capture the tracks of thermal emission mid-IR anomalies and methodology for practical future use of such phenomena in the early warning systems.

  18. Wide-band IR imaging in the NIR-MIR-FIR regions for in situ analysis of frescoes

    Science.gov (United States)

    Daffara, C.; Pezzati, L.; Ambrosini, D.; Paoletti, D.; Di Biase, R.; Mariotti, P. I.; Frosinini, C.

    2011-06-01

    Imaging methods offer several advantages in the field of conservation allowing to perform non-invasive inspection of works of art. In particular, non-invasive techniques based on imaging in different infrared (IR) regions are widely used for the investigation of paintings. Using radiation beyond the visible range, different characteristics of the inspected artwork may be revealed according to the bandwidth acquired. In this paper we present the recent results of a joint project among the two research institutes DIMEG and CNR-INO, and the restoration facility Opificio delle Pietre Dure, concerning the wide-band integration of IR imaging techniques, in the spectral ranges NIR 0.8-2.5 μm, MIR 3-5 μm, and FIR 8-12 μm, for in situ analysis of artworks. A joint, multi-mode use of reflection and thermal bands is proposed for the diagnostics of mural paintings, and it is demonstrated to be an effective tool in inspecting the layered structure. High resolution IR reflectography and, to a greater extent, IR imaging in the 3-5 μm band, are effectively used to characterize the superficial layer of the fresco and to analyze the stratigraphy of different pictorial layers. IR thermography in the 8-12 μm band is used to characterize the support deep structure. The integration of all the data provides a multi- layered and multi-spectral representation of the fresco that yields a comprehensive analysis.

  19. Thermogravimetric study of the reaction of uranium oxides with fluorine

    International Nuclear Information System (INIS)

    Komura, Motohiro; Sato, Nobuaki; Kirishima, Akira; Tochiyama, Osamu

    2008-01-01

    Thermogravimetric study of the reaction of uranium oxides with fluorine was conducted by TG-DTA method using anti-corrosion type differential thermobalance. When UO 2 was heated from R.T. to 500 deg. C in 5% F 2 /He atmosphere, the weight increase appeared at ca. 250 deg. C with an exothermic peak. Then the weight decreased slightly with a small exothermic peak followed by the complete volatilization with a large exothermic peak at ca. 350 deg. C. At a flow rate of 15, 30, 60 ml min -1 , there seemed to be no significant change for the fluorination of UO 2 . With the different heating rates of 1, 2, 5 and 10 deg. C min -1 , the fluorination peak shifted to higher temperature with increasing heating rates. For the comparison with thermogravimetric results, phase analysis by XRD method was conducted for the products obtained at different temperatures. At 260 deg. C, the product was UO 2 with a small amount of the intermediate compound, UO 2 F. The amount of this compound increased with increasing temperature up to 320 deg. C. Then another phase of UO 2 F 2 appeared at 340 deg. C but it was immediately fluorinated to the volatile fluoride. When U 3 O 8 was used as a starting material, it was found that the steep weight decrease peak appeared at ca. 350 deg. C and the uranium volatilized completely. This result suggests that fluorination of U 3 O 8 occurs at this temperature forming UF 6 . Uranium trioxide showed the similar fluorination behavior to that of U 3 O 8

  20. Crumpled rGO-supported Pt-Ir bifunctional catalyst prepared by spray pyrolysis for unitized regenerative fuel cells

    Science.gov (United States)

    Kim, In Gyeom; Nah, In Wook; Oh, In-Hwan; Park, Sehkyu

    2017-10-01

    Three-dimensional (3D) crumpled reduced graphene oxide supported Pt-Ir alloys that served as bifunctional oxygen catalysts for use in untized regenerative fuel cells were synthesized by a facile spray pyrolysis method. Pt-Ir catalysts supported on rGO (Pt-Ir/rGOs) were physically characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA) to observe change in composition by heat treatment, alloying, and morphological transition of the catalysts. Their catalytic activities and stabilities for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) conditions were electrochemically investigated using cyclic voltammetry (CV), linear sweep voltammetry (LSV), potential cycling and hold tests on the rotating disk electrode (RDE). Pt-Ir/rGO with no post heat-treatment (Pt-Ir/rGO_NP) showed a lower activity for ORR and OER although metal nanoparticles decorated on the support are relatively small. However, Pt-Ir/rGO showed remarkably enhanced activity following heat treatment, depending on temperature. Pt-Ir/rGO heat-treated at 600 °C after spray pyrolysis (Pt-Ir/rGO_P600) exhibited a higher activity and stability than a commercially available Pt/C catalyst kept under the ORR condition, and it also revealed a comparable OER activity and durability versus the commercial unsupported Ir catalyst.

  1. NMR and IR Spectroscopy for the Structural Characterization of Edible Fats and Oils: An Instrumental Analysis Laboratory

    Science.gov (United States)

    Crowther, Molly W.

    2008-01-01

    This article describes an upper-level instrumental laboratory for undergraduates that explores the complementary nature of IR and NMR spectroscopy for analysis of several edible fats and oils that are structurally similar but differ in physical properties and health implications. Five different fats and oils are analyzed for average chain length,…

  2. Sugar and acid content of Citrus prediction modeling using FT-IR fingerprinting in combination with multivariate statistical analysis.

    Science.gov (United States)

    Song, Seung Yeob; Lee, Young Koung; Kim, In-Jung

    2016-01-01

    A high-throughput screening system for Citrus lines were established with higher sugar and acid contents using Fourier transform infrared (FT-IR) spectroscopy in combination with multivariate analysis. FT-IR spectra confirmed typical spectral differences between the frequency regions of 950-1100 cm(-1), 1300-1500 cm(-1), and 1500-1700 cm(-1). Principal component analysis (PCA) and subsequent partial least square-discriminant analysis (PLS-DA) were able to discriminate five Citrus lines into three separate clusters corresponding to their taxonomic relationships. The quantitative predictive modeling of sugar and acid contents from Citrus fruits was established using partial least square regression algorithms from FT-IR spectra. The regression coefficients (R(2)) between predicted values and estimated sugar and acid content values were 0.99. These results demonstrate that by using FT-IR spectra and applying quantitative prediction modeling to Citrus sugar and acid contents, excellent Citrus lines can be early detected with greater accuracy. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Zr 2Ir 6B with an eightfold superstructure of the cubic perovskite-like boride ZrIr 3B 0.5: Synthesis, crystal structure and bonding analysis

    Science.gov (United States)

    Hermus, Martin; Fokwa, Boniface P. T.

    2010-04-01

    Single phase powder samples and single crystals of Zr 2Ir 6B were successfully synthesized by arc-melting the elements in a water-cooled copper crucible under an argon atmosphere. Superstructure reflections were observed both on powder and on single crystal diffraction data, leading to an eightfold superstructure of ZrIr 3B x phase. The new phase, which has a metallic luster, crystallizes in space group Fm3¯m (no. 225) with the lattice parameters a=7.9903(4) Å, V=510.14(4) Å 3. Its crystal structure was refined on the basis of powder as well as single crystal data. The single crystal refinement converged to R1=0.0239 and w R2=0.0624 for all 88 unique reflections and 6 parameters. Zr 2Ir 6B is isotypic to Ti 2Rh 6B and its structure can be described as a defect double perovskite, A2BB' O6, where the A site is occupied by zirconium, the B site by boron, the O site by iridium but the B' site is vacant, leading to the formation of empty and boron-filled octahedral Ir 6 clusters. According to the result of tight-binding electronic structure calculations, Ir-B and Ir-Zr interactions are mainly responsible for the structural stability of the phase. According to COHP bonding analysis, the strongest bonding occurs for the Ir-B contacts, and the Ir-Ir bonding within the empty clusters is two times stronger than that in the BIr 6 octahedra.

  4. Pb-H2O Thermogravimetric Plants. The Rankine Cycle

    International Nuclear Information System (INIS)

    Arosio, S.; Carlevaro, R.

    2000-01-01

    An economic evaluation concerning Pb-H 2 O thermogravimetric systems with an electric power in the range 200-1.000 kW has been done. Moreover, plant and running costs for a thermogravimetric and a Rankine cycle, 1 MW power, have been compared. Basically due to the lead charge, the plant cost of the former is higher: nevertheless such amount can be recuperated in less than three years, being higher the running cost of the latter [it

  5. Kinetics of Pyrolysis and Gasification Using Thermogravimetric and Thermovolumetric Analyses

    Directory of Open Access Journals (Sweden)

    Czerski Grzegorz

    2016-03-01

    Full Text Available The carbon dioxide gasification process of Miscanthus giganteus biomass was examined using two methods. First an isothermal thermovolumetric method was applied. The measurement was conducted at 950°C and pressure of 0.1 MPa. Based on the continuous analysis of different kinds of gases formed during the gasification process, the thermovolumetric method allowed the determination of yields and composition of the resulting gas as well as the rate constant of CO formation. Then a non-isothermal thermogravimetric method was applied, during which the loss of weight of a sample as a function of temperature was recorded. In the course of the measurement, the temperature was raised from ambient to 950°C and the pressure was 0.1 MPa. As a result, a change in the carbon conversion degree was obtained. Moreover, TGA methods allow distinguishing various stages of the gasification process such as primary pyrolysis, secondary pyrolysis and gasification, and determining kinetic parameters for each stage. The presented methods differs from each other as they are based either on the analysis of changes in the resulting product or on the analysis of changes in the supplied feedstock, but both can be successfully used to the effective examination of kinetics of the gasification process. In addition, an important advantage of both methods is the possibility to carry out the gasification process for different solid fuels as coal, biomass, or solid waste in the atmosphere of a variety of gasification agents.

  6. Sensitivity Range Analysis of Infrared (IR) Transmitter and Receiver Sensor to Detect Sample Position in Automatic Sample Changer

    International Nuclear Information System (INIS)

    Syirrazie Che Soh; Nolida Yussup; Nur Aira Abdul Rahman; Maslina Ibrahim

    2016-01-01

    Sensitivity range of IR Transmitter and Receiver Sensor influences the effectiveness of the sensor to detect position of a sample. Then the purpose of this analysis is to determine the suitable design and specification the electronic driver of the sensor to gain appropriate sensitivity range for required operation. The related activities to this analysis cover electronic design concept and specification, calibration of design specification and evaluation on design specification for required application. (author)

  7. Insulating phase in Sr{sub 2}IrO{sub 4}: An investigation using critical analysis and magnetocaloric effect

    Energy Technology Data Exchange (ETDEWEB)

    Bhatti, Imtiaz Noor; Pramanik, A.K., E-mail: akpramanik@mail.jnu.ac.in

    2017-01-15

    The nature of insulating phase in 5d based Sr{sub 2}IrO{sub 4} is quite debated as the theoretical as well as experimental investigations have put forward evidences in favor of both magnetically driven Slater-type and interaction driven Mott-type insulator. To understand this insulating behavior, we have investigated the nature of magnetic state in Sr{sub 2}IrO{sub 4} through studying critical exponents, low temperature thermal demagnetization and magnetocaloric effect. The estimated critical exponents do not exactly match with any universality class, however, the values obey the scaling behavior. The exponent values suggest that spin interaction in present material is close to mean-field model. The analysis of low temperature thermal demagnetization data, however, shows dual presence of localized- and itinerant-type of magnetic interaction. Moreover, field dependent change in magnetic entropy indicates magnetic interaction is close to mean-field type. While this material shows an insulating behavior across the magnetic transition, yet a distinct change in slope in resistivity is observed around T{sub c}. We infer that though the insulating phase in Sr{sub 2}IrO{sub 4} is more close to be Slater-type but the simultaneous presence of both Slater- and Mott-type is the likely scenario for this material. - Highlights: • Critical analysis shows Sr{sub 2}IrO{sub 4} has ferromagnetic ordering temperature T{sub c}~225 K. • Obtained critical exponents imply spin interaction is close to mean-field model. • Analysis of magneto-entropy data also supports mean-field type interaction. • However, the presence of both itinerant and localized spin interaction is evident. • Sr{sub 2}IrO{sub 4} has simultaneous presence of both Slater- and Mott-type insulating phase.

  8. TG/FT-IR characterization of additives typically employed in EPDM formulations

    Directory of Open Access Journals (Sweden)

    Natália Beck Sanches

    2015-06-01

    Full Text Available AbstractThermogravimetric analysis coupled to Fourier transform infrared spectroscopy (TG/FT-IR is a very popular technique for rubbers characterization. It involves analyses of the base polymer and additives. Ethylene–propylene–diene (EPDM rubbers are frequently investigated by TG/FT-IR; however, the focus has been the degradation temperature range of the polymer. In this study, unvulcanized and vulcanized EPDM rubber and its additives were investigated by TG/FT-IR, without solvent extraction, and in a wide temperature range. Initially, the additives were individually characterized. TG/FT-IR identified the characteristic groups of all the additives analyzed and distinguished them from each other. Afterwards, unvulcanized and vulcanized EPDM rubbers were investigated without prior extraction.TG/FT-IR detected absorptions due to the additives tetramethylthiuram monosulfide and 2-mercaptobenzothiazole. Both of these sulfur-containing additives were present in the EPDM formulation at concentrations of 0.7 phr (0.63 wt %. The TG/FT-IR technique had some limitations, because not all the additives in EPDM rubber were detected. Paraffin oil, stearic acid and 2,2,4-trimethyl-1,2-dihydroquinoline functional groups were not observed in either the unvulcanized or vulcanized EPDM. Nevertheless, in addition to the ability of this method to detect sulfur-containing groups, the lack of a pre-extraction reduces the time and effort required for additive analysis in rubbers.

  9. Crystallization and diffraction analysis of the serpin IRS-2 from the hard tick Ixodes ricinus

    International Nuclear Information System (INIS)

    Kovářová, Zuzana; Chmelař, Jindřich; Šanda, Miloslav; Brynda, Jiří; Mareš, Michael; Řezáčová, Pavlína

    2010-01-01

    Cleavage of the serpin IRS-2 from the hard tick I. ricinus by contaminating proteolytic activity mimicked the specific processing of the serpin by its target protease and resulted in a more stable form of the serpin which produced crystals that diffracted to 1.8 Å resolution. IRS-2 from the hard tick Ixodes ricinus belongs to the serpin family of protease inhibitors. It is produced in the salivary glands of the tick and its anti-inflammatory activity suggests that it plays a role in parasite–host interaction. Recombinant IRS-2 prepared by heterologous expression in a bacterial system was crystallized using the hanging-drop vapour-diffusion method. The crystals belonged to the primitive tetragonal space group P4 3 and diffracted to 1.8 Å resolution. Mass-spectrometric and electrophoretic analyses revealed that IRS-2 was cleaved by contaminating proteases during crystallization. This processing of IRS-2 mimicked the specific cleavage of the serpin by its target protease and resulted in a more stable form (the so-called relaxed conformation), which produced well diffracting crystals. Activity profiling with specific substrates and inhibitors demonstrated traces of serine and cysteine proteases in the protein stock solution

  10. Pyrolysis characteristics and kinetics of aquatic biomass using thermogravimetric analyzer.

    Science.gov (United States)

    Wu, Kejing; Liu, Ji; Wu, Yulong; Chen, Yu; Li, Qinghai; Xiao, Xin; Yang, Mingde

    2014-07-01

    The differences in pyrolysis process of three species of aquatic biomass (microalgae, macroalgae and duckweed) were investigated by thermogravimetric analysis (TGA). Three stages were observed during the pyrolysis process and the main decomposition stage could be divided further into three zones. The pyrolysis characteristics of various biomasses were different at each zone, which could be attributed to the differences in their components. A stepwise procedure based on iso-conversional and master-plots methods was used for the kinetic and mechanism analysis of the main decomposition stage. The calculation results based on the kinetic model was in good agreement with the experimental data of weight loss, and each biomass had an increasing activation energy of 118.35-156.13 kJ/mol, 171.85-186.46 kJ/mol and 258.51-268.71 kJ/mol in zone 1, 2 and 3, respectively. This study compares the pyrolysis behavior of various aquatic biomasses and provides basis for further applications of the biomass thermochemical conversion. Copyright © 2014. Published by Elsevier Ltd.

  11. Analysis of the development of missile-borne IR imaging detecting technologies

    Science.gov (United States)

    Fan, Jinxiang; Wang, Feng

    2017-10-01

    Today's infrared imaging guiding missiles are facing many challenges. With the development of targets' stealth, new-style IR countermeasures and penetrating technologies as well as the complexity of the operational environments, infrared imaging guiding missiles must meet the higher requirements of efficient target detection, capability of anti-interference and anti-jamming and the operational adaptability in complex, dynamic operating environments. Missileborne infrared imaging detecting systems are constrained by practical considerations like cost, size, weight and power (SWaP), and lifecycle requirements. Future-generation infrared imaging guiding missiles need to be resilient to changing operating environments and capable of doing more with fewer resources. Advanced IR imaging detecting and information exploring technologies are the key technologies that affect the future direction of IR imaging guidance missiles. Infrared imaging detecting and information exploring technologies research will support the development of more robust and efficient missile-borne infrared imaging detecting systems. Novelty IR imaging technologies, such as Infrared adaptive spectral imaging, are the key to effectively detect, recognize and track target under the complicated operating and countermeasures environments. Innovative information exploring techniques for the information of target, background and countermeasures provided by the detection system is the base for missile to recognize target and counter interference, jamming and countermeasure. Modular hardware and software development is the enabler for implementing multi-purpose, multi-function solutions. Uncooled IRFPA detectors and High-operating temperature IRFPA detectors as well as commercial-off-the-shelf (COTS) technology will support the implementing of low-cost infrared imaging guiding missiles. In this paper, the current status and features of missile-borne IR imaging detecting technologies are summarized. The key

  12. A Rapid Method of Crude Oil Analysis Using FT-IR Spectroscopy

    African Journals Online (AJOL)

    HP USER

    Nigerian Journal of Basic and Applied Science (June,2016), 24(1): 47-55 ... ABSTRACT: This study determines the viability of the use of Fourier Transform ... IR spectra of Crude oil sample containing a mixture of both degraded (sample 151).

  13. Method for Determining the Activation Energy Distribution Function of Complex Reactions by Sieving and Thermogravimetric Measurements.

    Science.gov (United States)

    Bufalo, Gennaro; Ambrosone, Luigi

    2016-01-14

    A method for studying the kinetics of thermal degradation of complex compounds is suggested. Although the method is applicable to any matrix whose grain size can be measured, herein we focus our investigation on thermogravimetric analysis, under a nitrogen atmosphere, of ground soft wheat and ground maize. The thermogravimetric curves reveal that there are two well-distinct jumps of mass loss. They correspond to volatilization, which is in the temperature range 298-433 K, and decomposition regions go from 450 to 1073 K. Thermal degradation is schematized as a reaction in the solid state whose kinetics is analyzed separately in each of the two regions. By means of a sieving analysis different size fractions of the material are separated and studied. A quasi-Newton fitting algorithm is used to obtain the grain size distribution as best fit to experimental data. The individual fractions are thermogravimetrically analyzed for deriving the functional relationship between activation energy of the degradation reactions and the particle size. Such functional relationship turns out to be crucial to evaluate the moments of the activation energy distribution, which is unknown in terms of the distribution calculated by sieve analysis. From the knowledge of moments one can reconstruct the reaction conversion. The method is applied first to the volatilization region, then to the decomposition region. The comparison with the experimental data reveals that the method reproduces the experimental conversion with an accuracy of 5-10% in the volatilization region and of 3-5% in the decomposition region.

  14. Geographic identification of Boletus mushrooms by data fusion of FT-IR and UV spectroscopies combined with multivariate statistical analysis

    Science.gov (United States)

    Yao, Sen; Li, Tao; Li, JieQing; Liu, HongGao; Wang, YuanZhong

    2018-06-01

    Boletus griseus and Boletus edulis are two well-known wild-grown edible mushrooms which have high nutrition, delicious flavor and high economic value distributing in Yunnan Province. In this study, a rapid method using Fourier transform infrared (FT-IR) and ultraviolet (UV) spectroscopies coupled with data fusion was established for the discrimination of Boletus mushrooms from seven different geographical origins with pattern recognition method. Initially, the spectra of 332 mushroom samples obtained from the two spectroscopic techniques were analyzed individually and then the classification performance based on data fusion strategy was investigated. Meanwhile, the latent variables (LVs) of FT-IR and UV spectra were extracted by partial least square discriminant analysis (PLS-DA) and two datasets were concatenated into a new matrix for data fusion. Then, the fusion matrix was further analyzed by support vector machine (SVM). Compared with single spectroscopic technique, data fusion strategy can improve the classification performance effectively. In particular, the accuracy of correct classification of SVM model in training and test sets were 99.10% and 100.00%, respectively. The results demonstrated that data fusion of FT-IR and UV spectra can provide higher synergic effect for the discrimination of different geographical origins of Boletus mushrooms, which may be benefit for further authentication and quality assessment of edible mushrooms.

  15. Temperature dependence of the resonance frequency of thermogravimetric devices

    NARCIS (Netherlands)

    Iervolino, E.; Riccio, M.; Van Herwaarden, A.W.; Irace, A.; Breglio, G.; Van der Vlist, W.; Sarro, P.M.

    2010-01-01

    This paper investigates the temperature dependence of the resonance frequency of thermogravimetric (TG) devices for tip heating over the temperature range of View the MathML source 25–600?C. The resonance frequency of a fabricated TG device shows to be temperature independent for tip heating up to

  16. Computer calculations of activation energy for pyrolysis from thermogravimetric curves

    International Nuclear Information System (INIS)

    Hussain, R.

    1994-01-01

    A BASIC programme to determine energy of activation for the degradation of polymers has been described. The calculations are based on the results of thermogravimetric curves. This method is applicable for those polymers which produce volatile products upon thermal degradation. (author)

  17. FT-IR spectroscopic analysis for studying Clostridium cell response to conversion of enzymatically hydrolyzed hay

    Science.gov (United States)

    Grube, Mara; Gavare, Marita; Nescerecka, Alina; Tihomirova, Kristina; Mezule, Linda; Juhna, Talis

    2013-07-01

    Grass hay is one of assailable cellulose containing non-food agricultural wastes that can be used as a carbohydrate source by microorganisms producing biofuels. In this study three Clostridium strains Clostridium acetobutylicum, Clostridium beijerinckii and Clostridium tetanomorphum, capable of producing acetone, butanol and ethanol (ABE) were adapted to convert enzymatically hydrolyzed hay used as a growth media additive. The results of growth curves, substrate degradation kinetics and FT-IR analyses of bacterial biomass macromolecular composition showed diverse strain-specific cell response to the growth medium composition.

  18. Dual emitter IrQ(ppy)2 for OLED applications: Synthesis and spectroscopic analysis

    International Nuclear Information System (INIS)

    Ciobotaru, I.C.; Polosan, S.; Ciobotaru, C.C.

    2014-01-01

    The synthesis of organometallic compound with iridium and two types of ligands, quinoline and phenylpyridine, was done successfully. The absorption spectra of this compound have shown broad peaks in a visible region assigned to metal-to-ligands charge transfer and in UV region assigned to intraligand absorptions. The photoluminescence spectra exhibit dual character in which the red emission is more intense than the green one. In cathodoluminescence measurements, under electron beam, the powder obtained after recrystallization from dichloromethane, shows similar behaviors with photoluminescence spectra. The cathodoluminescence images have shown a luminescent crystalline powder with triclinic structure. This compound exhibits combined vibrational modes, which proves the presence in the same molecule of both ligands. Density Functional Theory calculation was involved in order to identify the main vibrations of this compound. Highlights: • Mixed-ligand of IrQ(ppy) 2 synthesis which gives green and red phosphorescence due to the MCLT processes coming from two types of ligands. • Absorption, photoluminescence, infrared spectroscopy and cathodoluminescence measurements for characterization of IrQ(ppy) 2 organometallic compound. • Experimental results have been compared with the output files obtained from Density Functional Theory by using the Gaussian 03W software

  19. Pan-cancer analysis of somatic copy-number alterations implicates IRS4 and IGF2 in enhancer hijacking

    DEFF Research Database (Denmark)

    Weischenfeldt, Joachim Lütken; Dubash, Taronish; Drainas, Alexandros P

    2017-01-01

    overexpression resulting from CRE reorganization (e.g., enhancer hijacking) by integrating SCNAs, gene expression data and information on topologically associating domains (TADs). Analysis of 7,416 cancer genomes uncovered several pan-cancer candidate genes, including IRS4, SMARCA1 and TERT. We demonstrate...... intersecting with a TAD boundary mediate de novo formation of a 3D contact domain comprising IGF2 and a lineage-specific super-enhancer, resulting in high-level gene activation. Our framework enables systematic inference of CRE rearrangements mediating dysregulation in cancer....

  20. An improved synthesis, spectroscopic (FT-IR, NMR) study and DFT computational analysis (IR, NMR, UV-Vis, MEP diagrams, NBO, NLO, FMO) of the 1,5-methanoazocino[4,3-b]indole core structure

    Science.gov (United States)

    Uludağ, Nesimi; Serdaroğlu, Goncagül

    2018-03-01

    This study examines the synthesis of azocino[4,3-b]indole structure, which constitutes the tetracyclic framework of uleine, dasycarpidoneand tubifolidineas well as ABDE substructure of the strychnosalkaloid family. It has been synthesized by Fischer indolization of 2 and through the cylization of 4 by 2,3-dichlor-5-6-dicyanobenzoquinone (DDQ). 1H and 1C NMR chemical shifts have been predicted with GIAO approach and the calculated chemical shifts show very good agreement with observed shifts. FT-IR spectroscopy is important for the analysis of functional groups of synthesized compounds and we also supported FT-IR vibrational analysis with computational IR analysis. The vibrational spectral analysis was performed at B3LYP level of the theory in both the gas and the water phases and it was compared with the observed IR values for the important functional groups. The DFT calculations have been conducted to determine the most stable structure of the 1,2,3,4,5,6,7-Hexahydro-1,5-methanoazocino [4,3-b] indole (5). The Frontier Molecular Orbital Analysis, quantum chemical parameters, physicochemical properties have been predicted by using the same theory of level in both gas phase and the water phase, at 631 + g** and 6311++g** basis sets. TD- DFT calculations have been performed to predict the UV- Vis spectral analysis for this synthesized molecule. The Natural Bond Orbital (NBO) analysis have been performed at B3LYP level of theory to elucidate the intra-molecular interactions such as electron delocalization and conjugative interactions. NLO calculations were conducted to obtain the electric dipole moment and polarizability of the title compound.

  1. Analysis of pure and malachite green doped polysulfone sample using FT-IR technique

    Science.gov (United States)

    Nayak, Rashmi J.; Khare, P. K.; Nayak, J. G.

    2018-05-01

    The sample of pure and malachite green doped Polysulfone in the form of foil was prepared by isothermal immersion technique. For the preparation of pure sample 4 gm of Polysulfone was dissolved in 50 ml of Dimethyl farmamide (DMF) solvent, while for the preparation of doped sample 10 mg, 50 mg and 100 mg Malachite Green was mixed with 4 gm of Polysulfone respectively. For the study of structural characterization of these pure and doped sample, Fourier Transform Infra-Red Spectroscopy (FT-IR) technique was used. This study shows that the intensity of transmittance decreases as the ratio of doping increases in pure polysulfone. The reduction in intensity of transmittance is clearly apparent in the present case more over the bands were broader which indicates towards charge transfer interaction between the donar and acceptor molecule.

  2. Safety Analysis Report for Primary Capsule of Ir-192 Radiation Source

    International Nuclear Information System (INIS)

    Lee, J. C.; Bang, K. S.; Choi, W. S.; Seo, K. S.; Son, K. J.; Park, W. J.

    2008-12-01

    All of the source capsules to transport a special form radioactive material should be designed and fabricated in accordance with the design criteria prescribed in IAEA standards and domestic regulations. The objective of this project is to prove the safety of a primary capsule for Ir-192 radiation source which produced in the HANARO. The safety tests of primary capsules were carried out for the impact, percussion and heat conditions. And leakage tests were carried out before and after the each tests. The capsule showed slight scratches and their deformations were not found after each tests. It also met the allowable limits of leakage rate after each test. Therefore, it has been verified that the capsule was designed and fabricated to meet all requirements for the special form radioactive materials

  3. Analysis of cosmetic residues on a single human hair by ATR FT-IR microspectroscopy

    Science.gov (United States)

    Pienpinijtham, Prompong; Thammacharoen, Chuchaat; Naranitad, Suwimol; Ekgasit, Sanong

    2018-05-01

    In this work, ATR FT-IR spectra of single human hair and cosmetic residues on hair surface are successfully collected using a homemade dome-shaped Ge μIRE accessary installed on an infrared microscope. By collecting ATR spectra of hairs from the same person, the spectral patterns are identical and superimposed while different spectral features are observed from ATR spectra of hairs collected from different persons. The spectral differences depend on individual hair characteristics, chemical treatments, and cosmetics on hair surface. The "Contact-and-Collect" technique that transfers remarkable materials on the hair surface to the tip of the Ge μIRE enables an identification of cosmetics on a single hair. Moreover, the differences between un-split and split hairs are also studied in this report. These highly specific spectral features can be employed for unique identification or for differentiation of hairs based on the molecular structures of hairs and cosmetics on hairs.

  4. Thermogravimetric studies on the silicothermic reduction of uranium tetrafluoride under nitrogen

    International Nuclear Information System (INIS)

    Venkataramani, R.; Bhatt, Y.J.; Krishnamurthy, N.; Garg, S.P.

    1986-01-01

    This paper presents details of the experimental procedure and results obtained by thermogravimetric studies on the preparation of uranium nitrides by silicothermic reduction of uranium tetrafluoride under a nitrogen atmosphere. The folowing sequential steps are involved during the reaction: 4UF 4 +Si->4UF 3 +SiF 4 (g), 2UF 3 +Si+N 2 ->2UNF+SiF 4 (g), 4UNF+Si+N 2 ->2U 2 N 3 +SiF 4 (g), the uranium sesquintride U 2 N 3 obtained in the above process then decomposed at 1370 K under a dynamic vacuum of less than 10 -2 Tor to yield uranium mononitride of purity better than 99.9%, according to reaction 2U 2 N 3 ->4UN+N 2 (g). The chemical composition of the intermediate products formed during the sequential steps of the process, assessed by thermogravimetric and differential thermogravimetric studies, were further confirmed by chemical and X-ray analysis

  5. Analysis of Printing Substrate, Ink Age and Number of IR Drying Influence on Electrical Resistance of Conductive Inks

    Directory of Open Access Journals (Sweden)

    Josip Jerić

    2015-05-01

    Full Text Available As a result of availability of new technologies, functional printing as a segment has become one of the most interesting directions of research and development in graphic technology. Conductive inks are not a novelty and they already have broad possibilities in production of everyday products. There is still a big market for the broadening of their use, as well as a possibility of further enhancing their properties. This paper analyzes the influence of printing substrate, age of ink and the number of IR drying on the electrical resistance of the conductive inks. In the paper, subject of analysis was the change of electrical resistance in the line that was 9 cm long and 10 typographic points wide. The semi-automated screen-printing machine was used for printing. Three types of printing substrates were used; uncoated, coated and recycled paper. Two types of inks were used; newly opened ink and ink that was out of date for half year. After the printing, prints were dried using the IR dryer. Prints were dried once, and then additional three times. After the first and last drying, multimeter was used to measure electrical resistance of the lines. Analysis of the data shows that the older ink produces prints with higher electrical resistance. There are also notable differences in the electrical resistance based on the printing substrate.

  6. Thermogravimetric control of intermediate compounds in uranium metallurgy

    International Nuclear Information System (INIS)

    Gasco Sanchez, L.; Fernandez Cellini, R.

    1959-01-01

    The thermal decomposition of some intermediate compounds in the metallurgy of the uranium as uranium peroxide, ammonium uranate, uranium and ammonium penta-fluoride, uranium tetrafluoride and uranous oxide has been study by means of the Chevenard's thermo balance. Some data on pyrolysis of synthetic mixtures of intermediate compounds which may occasionally appear during the industrial process, are given. Thermogravimetric methods of control are suggested, usable in interesting products in the uranium metallurgy. (Author) 20 refs

  7. Combining FT-IR spectroscopy and multivariate analysis for qualitative and quantitative analysis of the cell wall composition changes during apples development.

    Science.gov (United States)

    Szymanska-Chargot, M; Chylinska, M; Kruk, B; Zdunek, A

    2015-01-22

    The aim of this work was to quantitatively and qualitatively determine the composition of the cell wall material from apples during development by means of Fourier transform infrared (FT-IR) spectroscopy. The FT-IR region of 1500-800 cm(-1), containing characteristic bands for galacturonic acid, hemicellulose and cellulose, was examined using principal component analysis (PCA), k-means clustering and partial least squares (PLS). The samples were differentiated by development stage and cultivar using PCA and k-means clustering. PLS calibration models for galacturonic acid, hemicellulose and cellulose content from FT-IR spectra were developed and validated with the reference data. PLS models were tested using the root-mean-square errors of cross-validation for contents of galacturonic acid, hemicellulose and cellulose which was 8.30 mg/g, 4.08% and 1.74%, respectively. It was proven that FT-IR spectroscopy combined with chemometric methods has potential for fast and reliable determination of the main constituents of fruit cell walls. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Development of a diamond waveguide sensor for sensitive protein analysis using IR quantum cascade lasers

    Science.gov (United States)

    Piron, P.; Vargas Catalan, E.; Haas, J.; Österlund, L.; Nikolajeff, F.; Andersson, P. O.; Bergström, J.; Mizaikoff, B.; Karlsson, M.

    2018-02-01

    Microfabricated diamond waveguides, between 5 and 20 μm thick, manufactured by chemical vapor deposition of diamond, followed by standard lithographic techniques and inductively coupled plasma etching of diamond, are used as bio-chemical sensors in the mid infrared domain: 5-11 μm. Infrared light, emitted from a broadly tunable quantum cascade laser with a wavelength resolution smaller than 20 nm, is coupled through the diamond waveguides for attenuated total reflection spectroscopy. The expected advantages of these waveguides are a high sensitivity due to the high number of internal reflections along the propagation direction, a high transmittance in the mid-IR domain, the bio-compatibility of diamond and the possibility of functionalizing the surface layer. The sensor will be used for analyzing different forms of proteins such as α-synuclein which is relevant in understanding the mechanism behind Parkinson's disease. The fabrication process of the waveguide, its characteristics and several geometries are introduced. The optical setup of the biosensor is described and our first measurements on two analytes to demonstrate the principle of the sensing method will be presented. Future use of this sensor includes the functionalization of the diamond waveguide sensor surface to be able to fish out alpha-synuclein from cerebrospinal fluid.

  9. Analysis of cosmetic residues on a single human hair by ATR FT-IR microspectroscopy.

    Science.gov (United States)

    Pienpinijtham, Prompong; Thammacharoen, Chuchaat; Naranitad, Suwimol; Ekgasit, Sanong

    2018-05-15

    In this work, ATR FT-IR spectra of single human hair and cosmetic residues on hair surface are successfully collected using a homemade dome-shaped Ge μIRE accessary installed on an infrared microscope. By collecting ATR spectra of hairs from the same person, the spectral patterns are identical and superimposed while different spectral features are observed from ATR spectra of hairs collected from different persons. The spectral differences depend on individual hair characteristics, chemical treatments, and cosmetics on hair surface. The "Contact-and-Collect" technique that transfers remarkable materials on the hair surface to the tip of the Ge μIRE enables an identification of cosmetics on a single hair. Moreover, the differences between un-split and split hairs are also studied in this report. These highly specific spectral features can be employed for unique identification or for differentiation of hairs based on the molecular structures of hairs and cosmetics on hairs. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. Analysis of IRS-1-mediated phosphatidylinositol 3-kinase activation in the adipose tissue of polycystic ovary syndrome patients complicated with insulin resistance

    Energy Technology Data Exchange (ETDEWEB)

    Yongli, Chu [Yantai Yuhuangding Hospital, Yantai (China). Dept. of Obstetrics and Gynecology; Hongyu, Qiu; Yongyu, Sun; Min, Li; Hongfa, Li

    2004-04-01

    Objective: To investigate the insulin receptor substance-1 (IRS-1)-mediated phosphatidylinositol-3 (PI-3) kinase activity in adipose tissue of polycystic ovary syndrome (PCOS) patients, and to explore molecular mechanisms of insulin resistance of PCOS. Methods: Blood and adipose tissue samples from patients with PCOS with insulin resistance (n=19), PCOS without insulin resistance (n=10) and controls (n=15) were collected. Serum luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone (T) were measured by chemiluminescence assay. Fasting insulin (FIN) was measured by radioimmunoassay. Fasting plasma glucose (FPG) was measured by oxidase assay. Insulin resistance index (IR) was calculated using homeostasis model assessment (HOMA) to analyze the relationship between these markers and insulin resistance. The tyrosine phosphorylation of IRS-1 was measured by immunoprecipitation and enhanced chemiluminescent immunoblotting technique. PI-3 kinase activity was detected by immunoprecipitation, thin-layer chromatography and gamma scintillation counting. The results were analyzed by statistical methods. Results: 1) The levels of serum LH, LH/FSH, T, FIN and HOMA-IR in PCOS without insulin resistance were significantly higher than those of control group (all P<0.05); the levels of serum LH, LH/FSH, T, FIN and HOMA-IR in PCOS with insulin resistance were significantly higher than those of PCOS without insulin resistance (all P<0.05). 2) The tyrosine phosphorylation analysis of IRS-1 showed that IRS-1 tyrosine phosphorylation was significantly decreased in PCOS with insulin resistance compared to that of PCOS without insulin resistance and control groups (P<0.01). 3) PI-3 kinase activity was significantly decreased (P<0.01) and negatively correlated with HOMA-IR. Conclusion: In consequence of the weaker signal caused by the change of upper stream signal molecule IRS-1 tyrosine phosphorylation, PI-3 kinase activity decreased, it affects the insulin signal

  11. Analysis of IRS-1-mediated phosphatidylinositol 3-kinase activation in the adipose tissue of polycystic ovary syndrome patients complicated with insulin resistance

    International Nuclear Information System (INIS)

    Chu Yongli; Qiu Hongyu; Sun Yongyu; Li Min; Li Hongfa

    2004-01-01

    Objective: To investigate the insulin receptor substance-1 (IRS-1)-mediated phosphatidylinositol-3 (PI-3) kinase activity in adipose tissue of polycystic ovary syndrome (PCOS) patients, and to explore molecular mechanisms of insulin resistance of PCOS. Methods: Blood and adipose tissue samples from patients with PCOS with insulin resistance (n=19), PCOS without insulin resistance (n=10) and controls (n=15) were collected. Serum luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone (T) were measured by chemiluminescence assay. Fasting insulin (FIN) was measured by radioimmunoassay. Fasting plasma glucose (FPG) was measured by oxidase assay. Insulin resistance index (IR) was calculated using homeostasis model assessment (HOMA) to analyze the relationship between these markers and insulin resistance. The tyrosine phosphorylation of IRS-1 was measured by immunoprecipitation and enhanced chemiluminescent immunoblotting technique. PI-3 kinase activity was detected by immunoprecipitation, thin-layer chromatography and gamma scintillation counting. The results were analyzed by statistical methods. Results: 1) The levels of serum LH, LH/FSH, T, FIN and HOMA-IR in PCOS without insulin resistance were significantly higher than those of control group (all P<0.05); the levels of serum LH, LH/FSH, T, FIN and HOMA-IR in PCOS with insulin resistance were significantly higher than those of PCOS without insulin resistance (all P<0.05). 2) The tyrosine phosphorylation analysis of IRS-1 showed that IRS-1 tyrosine phosphorylation was significantly decreased in PCOS with insulin resistance compared to that of PCOS without insulin resistance and control groups (P<0.01). 3) PI-3 kinase activity was significantly decreased (P<0.01) and negatively correlated with HOMA-IR. Conclusion: In consequence of the weaker signal caused by the change of upper stream signal molecule IRS-1 tyrosine phosphorylation, PI-3 kinase activity decreased, it affects the insulin signal

  12. Temperature-dependent IR-transition moment orientational analysis applied to thin supported films of poly-ε-caprolactone.

    Science.gov (United States)

    Kossack, Wilhelm; Schulz, Martha; Thurn-Albrecht, Thomas; Reinmuth, Jörg; Skokow, Viktor; Kremer, Friedrich

    2017-12-13

    A novel experimental setup is described which enables one to carry out infrared transition moment orientational analysis (IR-TMOA) depending on temperature. By this, three dimensional molecular order parameter tensors of IR-active transition dipole moments with respect to the sample coordinate system can be determined in their thermal evolution (35 °C < T < 59 °C). As an example crystallinity and macroscopic order of poly-ε-caprolcatone are monitored. Both remain largely unaltered up to T ∼ 50 °C, above which they decrease. These reductions are explained as the melting of flat-on crystalline lamellae that make up about 34% of the crystalline material. The remaining crystallites are arranged into bulk-like, confined spherulitic structures and do not melt by more than (3 ± 3)%. Therefore, flat-on oriented lamellae are supposed to be kinetically favored by confinement during melt crystallization but are thermodynamically less stable than two-dimensionally confined bulk-like spherulites.

  13. Some critical aspects of FT-IR, TGA, powder XRD, EDAX and SEM studies of calcium oxalate urinary calculi.

    Science.gov (United States)

    Joshi, Vimal S; Vasant, Sonal R; Bhatt, J G; Joshi, Mihir J

    2014-06-01

    Urinary calculi constitute one of the oldest afflictions of humans as well as animals, which are occurring globally. The calculi vary in shape, size and composition, which influence their clinical course. They are usually of the mixed-type with varying percentages of the ingredients. In medical management of urinary calculi, either the nature of calculi is to be known or the exact composition of calculi is required. In the present study, two selected calculi were recovered after surgery from two different patients for detailed examination and investigated by using Fourier-Transform infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TGA), powder X-ray diffraction (XRD), scanning electron microscopy and energy dispersive analysis of X-rays (EDAX) techniques. The study demonstrated that the nature of urinary calculi and presence of major phase in mixed calculi could be identified by FT-IR, TGA and powder XRD, however, the exact content of various elements could be found by EDAX only.

  14. Kinetics of reaction dimer fatty acid C_36 with 1,9 diamino nonane and determination of thermodynamic constants by use of thermogravimetric analysis tga, and rheological constants for the resulted polyamide

    International Nuclear Information System (INIS)

    Mohammad, H.; Falah, Al; Hammoy, M.

    2014-01-01

    Study the kinetics degradation of poly (dimeric acid C_36 with 1.9 – diamino nonane) was carried out by thermal analysis (TGA), and thermodynamic and equilibrium constants have been defined, moreover, study the kinetics of reaction between 1.9 – diamino nonane and dimer fatty acid C_36 was carried out in molten state, the reaction was performed at 160°, the acid value, and percentage of carboxylic functions of the product were determined. The polyamidation reaction was found to be of overall second order until conversion of 97% at 160°, then the order of reaction changes. The degree of dispersion, number molecular weight, weight molecular weight ,and viscosity molecular weight have been calculated during different times.The relationships between degree of dispersion, number Average molecular weight, weight average molecular weight, and viscosity molecular weight with time is linear at160°. Spectroscopy studies were carried out by infra-red and ultraviolet spectroscopy (author).

  15. X-ray diffraction, IR spectroscopy and thermal characterization of partially hydrolyzed guar gum.

    Science.gov (United States)

    Mudgil, Deepak; Barak, Sheweta; Khatkar, B S

    2012-05-01

    Guar gum was hydrolyzed using cellulase from Aspergillus niger at 5.6 pH and 50°C temperature. Hydrolyzed guar gum sample was characterized using Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction, dilute solution viscometry and rotational viscometry. Viscometry analysis of native guar gum showed a molecular weight of 889742.06, whereas, after enzymatic hydrolysis, the resultant product had a molecular weight of 7936.5. IR spectral analysis suggests that after enzymatic hydrolysis of guar gum there was no major transformation of functional group. Thermal analysis revealed no major change in thermal behavior of hydrolyzed guar gum. It was shown that partial hydrolysis of guar gum could be achieved by inexpensive and food grade cellulase (Aspergillus niger) having commercial importance and utilization as a functional soluble dietary fiber for food industry. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. AN ANALYSIS OF THE SHAPES OF INTERSTELLAR EXTINCTION CURVES. VI. THE NEAR-IR EXTINCTION LAW

    International Nuclear Information System (INIS)

    Fitzpatrick, E. L.; Massa, D.

    2009-01-01

    We combine new observations from the Hubble Space Telescope's Advanced Camera of Survey with existing data to investigate the wavelength dependence of near-IR (NIR) extinction. Previous studies suggest a power law form for NIR extinction, with a 'universal' value of the exponent, although some recent observations indicate that significant sight line-to-sight line variability may exist. We show that a power-law model for the NIR extinction provides an excellent fit to most extinction curves, but that the value of the power, β, varies significantly from sight line to sight line. Therefore, it seems that a 'universal NIR extinction law' is not possible. Instead, we find that as β decreases, R(V) ≡ A(V)/E(B - V) tends to increase, suggesting that NIR extinction curves which have been considered 'peculiar' may, in fact, be typical for different R(V) values. We show that the power-law parameters can depend on the wavelength interval used to derive them, with the β increasing as longer wavelengths are included. This result implies that extrapolating power-law fits to determine R(V) is unreliable. To avoid this problem, we adopt a different functional form for NIR extinction. This new form mimics a power law whose exponent increases with wavelength, has only two free parameters, can fit all of our curves over a longer wavelength baseline and to higher precision, and produces R(V) values which are consistent with independent estimates and commonly used methods for estimating R(V). Furthermore, unlike the power-law model, it gives R(V)s that are independent of the wavelength interval used to derive them. It also suggests that the relation R(V) = -1.36 E(K-V)/(E(B-V)) - 0.79 can estimate R(V) to ±0.12. Finally, we use model extinction curves to show that our extinction curves are in accord with theoretical expectations, and demonstrate how large samples of observational quantities can provide useful constraints on the grain properties.

  17. Optimization of sample absorbance for quantitative analysis in the presence of pathlength error in the IR and NIR regions

    International Nuclear Information System (INIS)

    Hirschfeld, T.; Honigs, D.; Hieftje, G.

    1985-01-01

    Optical absorbance levels for quantiative analysis in the presence of photometric error have been described in the past. In newer instrumentation, such as FT-IR and NIRA spectrometers, the photometric error is no longer limiting. In these instruments, pathlength error due to cell or sampling irreproducibility is often a major concern. One can derive optimal absorbance by taking both pathlength and photometric errors into account. This paper analyzes the cases of pathlength error >> photometric error (trivial) and various cases in which the pathlength errors and the photometric error are of the same order: adjustable concentration (trivial until dilution errors are considered), constant relative pathlength error (trivial), and constant absolute pathlength error. The latter, in particular, is analyzed in detail to give the behavior of the error, the behavior of the optimal absorbance in its presence, and the total error levels attainable

  18. IR spectroscopy together with multivariate data analysis as a process analytical tool for in-line monitoring of crystallization process and solid-state analysis of crystalline product

    DEFF Research Database (Denmark)

    Pöllänen, Kati; Häkkinen, Antti; Reinikainen, Satu-Pia

    2005-01-01

    -ray powder diffraction (XRPD) as a reference technique. In order to fully utilize DRIFT, the application of multivariate techniques are needed, e.g., multivariate statistical process control (MSPC), principal component analysis (PCA) and partial least squares (PLS). The results demonstrate that multivariate...... Fourier transform infra red (ATR-FTIR) spectroscopy provides valuable information on process, which can be utilized for more controlled crystallization processes. Diffuse reflectance Fourier transform infra red (DRIFT-IR) is applied for polymorphic characterization of crystalline product using X......Crystalline product should exist in optimal polymorphic form. Robust and reliable method for polymorph characterization is of great importance. In this work, infra red (IR) spectroscopy is applied for monitoring of crystallization process in situ. The results show that attenuated total reflection...

  19. Ir and Rare Earth's Elements determination by Neutron Activation Analysis and ICP - MS in soil samples

    Science.gov (United States)

    Salvini, A.; Cattadori, C.; Broggini, C.; Cagnazzo, M.; Ori, Gian Gabriele; Nisi, S.; Borio, A.; Manera, S.

    2006-05-01

    The platinum metals depleted in the earth's crust are relative to their cosmic abundance; concentration of these elements in sediments may thus indicate influxes of extraterrestrial material. Analysis of these parameters are done easily by Neutron Activation Analysis (NAA) and comparative results with ICP-MS technique show a good match. Results, adjust parameters and limits of this method will be displayed in tables.

  20. Carrier Dynamics Analysis in Metal-SemiconductorMetal Device for mid-IR Silicon Photonics

    DEFF Research Database (Denmark)

    Hui, Alvin Tak Lok; Ding, Yunhong; Hu, Hao

    A modelling platform for active carrier removal based on metal-semiconductor-metal structure is reported on analysis of carrier dynamics. The analysis reveals electric current hot spots exist in geometric singularities and curly trajectory of carriers should be considered when accurately estimati...

  1. Carrier dynamics analysis in metal-semiconductor-metal device for mid-IR silicon photonics

    DEFF Research Database (Denmark)

    Hui, Alvin Tak Lok; Ding, Yunhong; Hu, Hao

    2017-01-01

    A modelling platform for active carrier removal based on metal-semiconductor-metal structure is reported on analysis of carrier dynamics. The analysis reveals electric current hot spots exist in geometric singularities and curly trajectory of carriers should be considered when accurately estimati...

  2. Impaired Insulin Signaling is Associated with Hepatic Mitochondrial Dysfunction in IR+/−-IRS-1+/− Double Heterozygous (IR-IRS1dh Mice

    Directory of Open Access Journals (Sweden)

    Andras Franko

    2017-05-01

    Full Text Available Mitochondria play a pivotal role in energy metabolism, but whether insulin signaling per se could regulate mitochondrial function has not been identified yet. To investigate whether mitochondrial function is regulated by insulin signaling, we analyzed muscle and liver of insulin receptor (IR+/−-insulin receptor substrate-1 (IRS-1+/− double heterozygous (IR-IRS1dh mice, a well described model for insulin resistance. IR-IRS1dh mice were studied at the age of 6 and 12 months and glucose metabolism was determined by glucose and insulin tolerance tests. Mitochondrial enzyme activities, oxygen consumption, and membrane potential were assessed using spectrophotometric, respirometric, and proton motive force analysis, respectively. IR-IRS1dh mice showed elevated serum insulin levels. Hepatic mitochondrial oxygen consumption was reduced in IR-IRS1dh animals at 12 months of age. Furthermore, 6-month-old IR-IRS1dh mice demonstrated enhanced mitochondrial respiration in skeletal muscle, but a tendency of impaired glucose tolerance. On the other hand, 12-month-old IR-IRS1dh mice showed improved glucose tolerance, but normal muscle mitochondrial function. Our data revealed that deficiency in IR/IRS-1 resulted in normal or even elevated skeletal muscle, but impaired hepatic mitochondrial function, suggesting a direct cross-talk between insulin signaling and mitochondria in the liver.

  3. Volatility-dependent 2D IR correlation analysis of traditional Chinese medicine ‘Red Flower Oil’ preparation from different manufacturers

    Science.gov (United States)

    Wu, Yan-Wen; Sun, Su-Qin; Zhou, Qun; Tao, Jia-Xun; Noda, Isao

    2008-06-01

    As a traditional Chinese medicine (TCM), 'Red Flower Oil' preparation is widely used as a household remedy in China and Southeast Asia. Usually, the preparation is a mixture of several plant essential oils with different volatile features, such as wintergreen oil, turpentine oil and clove oil. The proportions of these plant essential oils in 'Red Flower Oil' vary from different manufacturers. Thus, it is important to develop a simple and rapid evaluation method for quality assurance of the preparations. Fourier transform infrared (FT-IR) was applied and two-dimensional correlation infrared spectroscopy (2D IR) based on the volatile characteristic of samples was used to enhance the resolution of FT-IR spectra. 2D IR technique could, not only easily provide the composition and their volatile sequences in 'Red flower Oil' preparations, but also rapidly discriminate the subtle differences in products from different manufacturers. Therefore, FT-IR combined with volatility-dependent 2D IR correlation analysis provides a very fast and effective method for the quality control of essential oil mixtures in TCM.

  4. Validation of Correction Algorithms for Near-IR Analysis of Human Milk in an Independent Sample Set-Effect of Pasteurization.

    Science.gov (United States)

    Kotrri, Gynter; Fusch, Gerhard; Kwan, Celia; Choi, Dasol; Choi, Arum; Al Kafi, Nisreen; Rochow, Niels; Fusch, Christoph

    2016-02-26

    Commercial infrared (IR) milk analyzers are being increasingly used in research settings for the macronutrient measurement of breast milk (BM) prior to its target fortification. These devices, however, may not provide reliable measurement if not properly calibrated. In the current study, we tested a correction algorithm for a Near-IR milk analyzer (Unity SpectraStar, Brookfield, CT, USA) for fat and protein measurements, and examined the effect of pasteurization on the IR matrix and the stability of fat, protein, and lactose. Measurement values generated through Near-IR analysis were compared against those obtained through chemical reference methods to test the correction algorithm for the Near-IR milk analyzer. Macronutrient levels were compared between unpasteurized and pasteurized milk samples to determine the effect of pasteurization on macronutrient stability. The correction algorithm generated for our device was found to be valid for unpasteurized and pasteurized BM. Pasteurization had no effect on the macronutrient levels and the IR matrix of BM. These results show that fat and protein content can be accurately measured and monitored for unpasteurized and pasteurized BM. Of additional importance is the implication that donated human milk, generally low in protein content, has the potential to be target fortified.

  5. Validation of Correction Algorithms for Near-IR Analysis of Human Milk in an Independent Sample Set—Effect of Pasteurization

    Science.gov (United States)

    Kotrri, Gynter; Fusch, Gerhard; Kwan, Celia; Choi, Dasol; Choi, Arum; Al Kafi, Nisreen; Rochow, Niels; Fusch, Christoph

    2016-01-01

    Commercial infrared (IR) milk analyzers are being increasingly used in research settings for the macronutrient measurement of breast milk (BM) prior to its target fortification. These devices, however, may not provide reliable measurement if not properly calibrated. In the current study, we tested a correction algorithm for a Near-IR milk analyzer (Unity SpectraStar, Brookfield, CT, USA) for fat and protein measurements, and examined the effect of pasteurization on the IR matrix and the stability of fat, protein, and lactose. Measurement values generated through Near-IR analysis were compared against those obtained through chemical reference methods to test the correction algorithm for the Near-IR milk analyzer. Macronutrient levels were compared between unpasteurized and pasteurized milk samples to determine the effect of pasteurization on macronutrient stability. The correction algorithm generated for our device was found to be valid for unpasteurized and pasteurized BM. Pasteurization had no effect on the macronutrient levels and the IR matrix of BM. These results show that fat and protein content can be accurately measured and monitored for unpasteurized and pasteurized BM. Of additional importance is the implication that donated human milk, generally low in protein content, has the potential to be target fortified. PMID:26927169

  6. Thermogravimetric kinetic model of the pyrolysis and combustion of an ethylene-vinyl acetate copolymer refuse

    Energy Technology Data Exchange (ETDEWEB)

    Angela N. Garcia; Rafael Font [Universidad de Alicante, Alicante (Spain). Faculty of Sciences

    2004-06-01

    A kinetic study of the pyrolysis as well as the combustion of EVA copolymer refuse originating from the footwear industry was carried out by thermogravimetric analysis. Different runs were performed at heating rates between 5-20{sup o}C min{sup -1} and atmospheres with different percentages of oxygen: 0, 10 and 20% (v/v). Pyrolysis and combustion processes can be simulated by two series reactions. The results obtained indicate that the second reaction begins when the first one is almost finished which implies that a good correlation is also obtained by simulation of the thermal decomposition of two independent fractions. 32 refs., 4 figs., 3 tabs.

  7. Thermogravimetric study of γ-irradiated lanthanum oxalate

    International Nuclear Information System (INIS)

    Nayak, H.; Bhatta, D.

    2000-01-01

    Thermogravimetric study of La 2 (C 2 O 4 ) 3 , exposed to different doses (5.0 - 50.0 x 10 -2 MGy) of γ-rays has been carried out. Marginal effect is observed at lower doses which is prominent at higher dose (5.0 x 10 -1 MGy). The radiolytic damaged entities, generated by irradiation favours the reaction by creating new potential nucleation centres in the lattice. The solid product, La 2 O 3 formed by irradiation also acts as a heterogeneous catalyst and brings out changes in the reactivity of the solid. (author)

  8. FT-IR spectroscopy and multivariate analysis as an auxiliary tool for diagnosis of mental disorders: Bipolar and schizophrenia cases

    Science.gov (United States)

    Ogruc Ildiz, G.; Arslan, M.; Unsalan, O.; Araujo-Andrade, C.; Kurt, E.; Karatepe, H. T.; Yilmaz, A.; Yalcinkaya, O. B.; Herken, H.

    2016-01-01

    In this study, a methodology based on Fourier-transform infrared spectroscopy and principal component analysis and partial least square methods is proposed for the analysis of blood plasma samples in order to identify spectral changes correlated with some biomarkers associated with schizophrenia and bipolarity. Our main goal was to use the spectral information for the calibration of statistical models to discriminate and classify blood plasma samples belonging to bipolar and schizophrenic patients. IR spectra of 30 samples of blood plasma obtained from each, bipolar and schizophrenic patients and healthy control group were collected. The results obtained from principal component analysis (PCA) show a clear discrimination between the bipolar (BP), schizophrenic (SZ) and control group' (CG) blood samples that also give possibility to identify three main regions that show the major differences correlated with both mental disorders (biomarkers). Furthermore, a model for the classification of the blood samples was calibrated using partial least square discriminant analysis (PLS-DA), allowing the correct classification of BP, SZ and CG samples. The results obtained applying this methodology suggest that it can be used as a complimentary diagnostic tool for the detection and discrimination of these mental diseases.

  9. Near-IR laser-based spectrophotometer for comparative analysis of isotope content of CO2 in exhale air samples

    International Nuclear Information System (INIS)

    Stepanov, E V; Glushko, A N; Kasoev, S G; Koval', A V; Lapshin, D A

    2011-01-01

    We present a laser spectrophotometer aimed at high-accuracy comparative analysis of content of 12 CO 2 and 13 CO 2 isotope modifications in the exhale air samples and based on a tunable near-IR diode laser (2.05 μm). The two-channel optical scheme of the spectrophotometer and the special digital system for its control are described. An algorithm of spectral data processing aimed at determining the difference in the isotope composition of gas mixtures is proposed. A few spectral regions (near 4880 cm -1 ) are determined to be optimal for analysis of relative content of 12 CO 2 and 13 CO 2 in the exhale air. The use of the proposed spectrophotometer scheme and the developed algorithm makes the results of the analysis less susceptible to the influence of the interference in optical elements, to the absorption in the open atmosphere, to the slow drift of the laser pulse envelope, and to the offset of optical channels. The sensitivity of the comparative analysis of the isotope content of CO 2 in exhale air samples, achieved using the proposed scheme, is estimated to be nearly 0.1‰.

  10. Thermal Analysis, FT-IR Spectroscopy and Optical Microscopy as a Tool for Characterization of Marble

    Czech Academy of Sciences Publication Activity Database

    Plevová, Eva; Kožušníková, Alena; Vaculíková, Lenka

    2009-01-01

    Roč. 5, č. 9 (2009), s. 149-150 ISSN 1336-7242. [Zjazd chemikov /61./. 07.09.2009-11.09.2009, Tatranské Matliare] R&D Projects: GA ČR GP105/07/P416; GA ČR GA105/08/1398 Institutional research plan: CEZ:AV0Z30860518 Keywords : marbles * thermal analysis * thermomechanical analysis Subject RIV: CB - Analytical Chemistry, Separation

  11. Automation of a McBain-Bakr-type thermogravimetric analyzer using a digital image correlation technique

    International Nuclear Information System (INIS)

    Trexler, M.D.; Sanders, T.H. Jr.; Singh, P.M.

    2006-01-01

    Thermogravimetric analysis was used to obtain corrosion kinetics data for several materials in high-temperature environments. A thermogravimetric analyzer has been developed that uses a McBain-Bakr quartz spring balance in conjunction with a digital image acquisition and analysis package to accurately characterize materials through image correlation. This provides a new method for automatically measuring mass changes continuously with a variable resolution depending on the spring component. The decomposition of calcium oxalate was used to verify the validity of the technique. The results show two reactions, whose reaction temperatures were determined by the intercept method, upon heating to 650 deg. C. The mass loss at the first reaction temperature, 200 deg. C, was 20% and a 30% loss was observed at 500 deg. C. Comparison of the experimentally obtained results with those of other researchers who used commercial instruments suggests that the method of using digital image analysis in conjunction with a spring to monitor mass change is a viable and accurate replacement for automatic electrobalances and cathetometers for thermal analysis of materials. Additional comparison between corrosion tests performed on SA210 steel in H 2 S using both a commercial thermobalance and the developed technique confirmed that high-temperature corrosion can be monitored accurately with the proposed method

  12. An IR Sounding-Based Analysis of the Saharan Air Layer in North Africa

    Science.gov (United States)

    Nicholls, Stephen D.; Mohr, Karen I.

    2018-01-01

    Intense daytime surface heating over barren-to-sparsely vegetated surfaces results in dry convective mixing. In the absence of external forcing such as mountain waves, the dry convection can produce a deep, well-mixed, nearly isentropic boundary layer that becomes a well-mixed residual layer in the evening. These well-mixed layers (WML) retain their unique mid-tropospheric thermal and humidity structure for several days. To detect the SAL and characterize its properties, AIRS Level 2 Ver. 6 temperature and humidity products (2003-Present) are evaluated against rawinsondes and compared to model analysis at each of the 55 rawinsonde stations in northern Africa. To distinguish WML from Saharan air layers (WMLs of Saharan origin), the detection involved a two-step process: 1) algorithm-based detection of WMLs in dry environments (less than 7 g per kilogram mixing ratio) 2) identification of Sahara air layers (SAL) by applying Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) back trajectories to determine the history of each WML. WML occurrence rates from AIRS closely resemble that from rawinsondes, yet rates from model analysis were up to 30% higher than observations in the Sahara due to model errors. Despite the overly frequent occurrence of WMLs from model analysis, HYSPLIT trajectory analysis showed that SAL occurrence rates (given a WML exists) from rawinsondes, AIRS, and model analysis were nearly identical. Although the number of WMLs varied among the data sources, the proportion of WMLs which were classified as SAL was nearly the same. The analysis of SAL bulk properties showed that AIRS and model analysis exhibited a slight warm and moist bias relative to rawinsondes in non-Saharan locations, but model analysis was notably warmer than rawinsondes and AIRS within the Sahara. The latter result is likely associated with the dearth of available data assimilated by model analysis in the Sahara. The variability of SAL thicknesses was reasonably

  13. Thermogravimetric analysis of multi-stage hydropyrolysis of different coals

    Energy Technology Data Exchange (ETDEWEB)

    Li, W.; Wang, N.; Li, B [Chinese Academy of Sciences, Taiyuan (China). State Key Lab. of Coal Conversion

    2001-09-01

    Based on the characteristic of hydropyrolysis (HyPy), a multi-stage MHyPy of different coals was investigated using thermogravimetry. The results show that keeping the near peak temperature for some time in HyPy process can obviously increase the conversion rate, which is believed due to the full match between formation rate of free radicals and supply of hydrogen. The fast heating in MHyPy process results in the same conversion rate as that of the slow heating in HyPy process, which leads to the less reaction time and high yield of oil. The effect of MHyPy depends on the coal structure itself and it is notable for the coal with high H/C ratio. This suggests that the external hydrogen promotes the reaction between intrinsic hydrogen and free radicals. The MHyPy improves the removal of sulfur and nitrogen. 5 refs., 7 figs., 2 tabs.

  14. Carbon elimination from silicon kerf: Thermogravimetric analysis and mechanistic considerations.

    Science.gov (United States)

    Vazquez-Pufleau, Miguel; Chadha, Tandeep S; Yablonsky, Gregory; Biswas, Pratim

    2017-01-18

    40% of ultrapure silicon is lost as kerf during slicing to produce wafers. Kerf is currently not being recycled due to engineering challenges and costs associated with removing its abundant impurities. Carbon left behind from the lubricant remains as one of the most difficult contaminants to remove in kerf without significant silicon oxidation. The present work enables to better understand the mechanism of carbon elimination in kerf which can aid the design of better processes for kef recycling and low cost photovoltaics. In this paper, we studied the kinetics of carbon elimination from silicon kerf in two atmospheres: air and N 2, under a regime of no-diffusion-limitation. We report the apparent activation energy in both atmospheres using three methods: Kissinger, and two isoconversional approaches. In both atmospheres, a bimodal apparent activation energy is observed, suggesting a two stage process. A reaction mechanism is proposed in which (a) C-C and C-O bond cleavage reactions occur in parallel with polymer formation; (b) at higher temperatures, this polymer fully degrades in air but leaves a tarry residue in N 2 that accounts for about 12% of the initial total carbon.

  15. Thermogravimetric evaluation of the suitability of precursors for MOCVD

    International Nuclear Information System (INIS)

    Kunte, G V; Shivashankar, S A; Umarji, A M

    2008-01-01

    A method based on the Langmuir equation for the estimation of vapour pressure and enthalpy of sublimation of subliming compounds is described. The variable temperature thermogravimetric/differential thermogravimetric (TG/DTG) curve of benzoic acid is used to arrive at the instrument parameters. Employing these parameters, the vapour pressure–temperature curves are derived for salicylic acid and camphor from their TG/DTG curves. The values match well with vapour pressure data in the literature, obtained by effusion methods. By employing the Clausius–Clapeyron equation, the enthalpy of sublimation could be calculated. Extending the method further, two precursors for metal-organic chemical vapour deposition (MOCVD) of titanium oxide bis-isopropyl bis tert-butyl 2-oxobutanoato titanium, Ti(O i Pr) 2 (tbob) 2 , and bis-oxo-bis-tertbutyl 2-oxobutanoato titanium, [TiO(tbob) 2 ] 2 , have been evaluated. The complex Ti(O i Pr) 2 (tbob) 2 is found to be a more suitable precursor. This approach can be helpful in quickly screening for the suitability of a compound as a CVD precursor

  16. The genetic analysis of heading time in hybrid rice IR54 and its early-maturity mutant-5460

    International Nuclear Information System (INIS)

    Zhou Yuanchang; Cai Junmai; Li Weiming

    1994-01-01

    V 20 A, IR 54 and its early mutant line 5460 were used as parents in three crosses. The heading time of radiation induced 5460 was 35(1986)∼40(1989) days earlier than that of IR 54 , and the F 1 plants of 5460/IR 54 showed a heading time close to that of their middle-parent. The segregation ratio of early-, intermediate- and late heading plants are given. From the segregation patterns, it may be assumed that three dominant genes, A,B and C, are involved and when they are combined, their complementary interaction expresses a late-heading phenotype which is strongly sensitive to photo-period. As V 20 A is previously suggested to have abC, it is expected that IR 54 has ABc, and 5460 has Abc. This means that gene b in 5460 is a single locus recessive mutation for early-maturity from gene B in IR 54

  17. Evaluation of oil thickness by neural network analysis of IR imagery

    International Nuclear Information System (INIS)

    Wood, P.; Strachan, I.; Davies, L.; Lunel, T.

    1997-01-01

    The feasibility of using neural network analysis of conventional thermal infra-red data gathered from surveillance aircraft to determine the thickness of oil at sea, was examined. Sea trial data was examined using Multi-Layer Perceptron neural network architecture, based on indications that it was the most appropriate configuration for determining oil thickness. Core input variables included oil brightness, time of day, sea brightness, wind speed, oil type, and sea temperature. Other variables, such as altitude, wave height, air temperature, camera gain, and others, did not appear to produce any significant difference in the prediction performance. By using only a restricted sea trial data set in training the network, it was found that it was possible to correctly classify about 80 per cent of the data into one of four thickness classes. Since there was no additional data available to validate the network, these results were considered encouraging, but not definitive. Additional data will be collected in planned future sea trials to further evaluate the accuracy of the trained network. 4 refs., 6 tabs., 4 figs

  18. IR thermographic observation and shear bands plasticity analysis in Fe-based metallic glass

    International Nuclear Information System (INIS)

    Bouzakher, B.; Benameur, T.; Sidhom, H.

    2009-01-01

    Infrared thermography observation and in situ atomic force microscopy characterization were carried out to investigate the mechanical damage processes at the edge-notch region of large ribbons of Fe 78 Si 10 B 12 metallic glass. An obvious thermoelastic and inelastic degradation phenomenon was observed ahead at the notched region of the specimens, which probably result from free volume accumulation process and shear band activity during plane stress solicitations. Moreover, AFM topographic and frictional analysis of changes in the crack path during stable crack propagation regime revealed a periodic morphology evolution, formation of nanoscale damage cavity in the range of 20-140 nm and a maximum temperature rise ahead of the pre-crack tip was found in the order of 1.5 deg. C. The nanometer scaled shear offset, discreteness and shear bands density were determined. While these key parameters play a role in observing a large plastic zone in front of the crack, however they are unable to explain the distinct intrinsic ductility of some monolithic metallic glasses. A general Mohr-Coulomb-type constitutive description was used to deduce analytic expressions for prediction of the variation of hydrostatic component of the applied stress to the shear stress ratio as function of Poisson's ratio.

  19. Rapid discrimination of sea buckthorn berries from different H. rhamnoides subspecies by multi-step IR spectroscopy coupled with multivariate data analysis

    Science.gov (United States)

    Liu, Yue; Zhang, Ying; Zhang, Jing; Fan, Gang; Tu, Ya; Sun, Suqin; Shen, Xudong; Li, Qingzhu; Zhang, Yi

    2018-03-01

    As an important ethnic medicine, sea buckthorn was widely used to prevent and treat various diseases due to its nutritional and medicinal properties. According to the Chinese Pharmacopoeia, sea buckthorn was originated from H. rhamnoides, which includes five subspecies distributed in China. Confusion and misidentification usually occurred due to their similar morphology, especially in dried and powdered forms. Additionally, these five subspecies have vital differences in quality and physiological efficacy. This paper focused on the quick classification and identification method of sea buckthorn berry powders from five H. rhamnoides subspecies using multi-step IR spectroscopy coupled with multivariate data analysis. The holistic chemical compositions revealed by the FT-IR spectra demonstrated that flavonoids, fatty acids and sugars were the main chemical components. Further, the differences in FT-IR spectra regarding their peaks, positions and intensities were used to identify H. rhamnoides subspecies samples. The discrimination was achieved using principal component analysis (PCA) and partial least square-discriminant analysis (PLS-DA). The results showed that the combination of multi-step IR spectroscopy and chemometric analysis offered a simple, fast and reliable method for the classification and identification of the sea buckthorn berry powders from different H. rhamnoides subspecies.

  20. Nickel hydroxide electrode. 3: Thermogravimetric investigations of nickel (II) hydroxides

    Science.gov (United States)

    Dennstedt, W.; Loeser, W.

    1982-01-01

    Water contained in Ni hydroxide influences its electrochemical reactivity. The water content of alpha and beta Ni hydroxides is different with respect to the amount and bond strength. Thermogravimetric experiments show that the water of the beta Ni hydroxides exceeding the stoichiometric composition is completely removed at 160 deg. The water contained in the interlayers of the beta hydroxide, however, is removed only at higher temperatures, together with the water originating from the decomposition of the hydroxide. These differences are attributed to the formation of II bonds within the interlayers and between interlayers and adjacent main layers. An attempt is made to explain the relations between water content and the oxidizability of the Ni hydroxides.

  1. Hydrogen Adsorption in Zeolite Studied with Sievert and Thermogravimetric Methods

    International Nuclear Information System (INIS)

    Lesnicenoks, P; Sivars, A; Grinberga, L; Kleperis, J

    2012-01-01

    Natural clinoptilolite (mixture from clinoptilolite, quartz and muscovite) is activated with palladium and tested for hydrogen adsorption capability at temperatures RT - 200°C. Thermogravimetric and volumetric methods showed that zeolite activated with palladium (1.25%wt) shows markedly high hydrogen adsorption capacity - up to 3 wt%. Lower amount of adsorbed hydrogen (∼1.5 wt%) was found for raw zeolite and activated with higher amount of palladium sample. Hypothesis is proposed that the heating of zeolite in argon atmosphere forms and activates the pore structure in zeolite material, where hydrogen encapsulation (trapping) is believed to occur when cooling down to room temperature. An effect of catalyst (Pd) on hydrogen sorption capability is explained by spillover phenomena were less-porous fractions of natural clinoptilolite sample (quartz and muscovite) are involved.

  2. A simplification of the deuterium oxide dilution technique using FT-IR analysis of plasma, for estimating piglet milk intake

    International Nuclear Information System (INIS)

    Glencross, B.D.; Tuckey, R.C.; Hartmann, P.E.; Mullan, B.P.

    1997-01-01

    Previous studies estimating milk intake using deuterium oxide (D 2 O) as a tracer have required sublimation of the sample fluid (usually plasma) to remove solids and retrieve total water. This procedure has been simplified by directly measuring the D 2 O content of plasma with a Fourier transform-infrared (FT-IR) spectrometer, removing the requirement for sample sublimation. Comparisons of samples that were split and then analysed as water of sublimation and as total plasma were performed. It was found that the direct analysis of the plasma could be achieved without a loss in fidelity of the results (sublimated v. plasma, r 2 = 0.976; n = 26). Linearity of assay standards was very high (r 2 > 0.997). The modified technique was used to determine the milk intake by piglets from litters of 7 sows during established lactation (Days 10-15). Water turnover (WTO) was shown to be the primary point by which differences in the piglet milk intakes were influenced. Differences in the milk composition had minimal effect on the milk intake determinations. Milk intake by each piglet was shown to be strongly correlated to piglet growth (r 2 = 0.59, P 2 = 0.84, P < 0.01). Copyright (1997) CSIRO Australia

  3. Fourier Transform Infrared Spectroscopy (FT-IR) and Simple Algorithm Analysis for Rapid and Non-Destructive Assessment of Developmental Cotton Fibers.

    Science.gov (United States)

    Liu, Yongliang; Kim, Hee-Jin

    2017-06-22

    With cotton fiber growth or maturation, cellulose content in cotton fibers markedly increases. Traditional chemical methods have been developed to determine cellulose content, but it is time-consuming and labor-intensive, mostly owing to the slow hydrolysis process of fiber cellulose components. As one approach, the attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy technique has also been utilized to monitor cotton cellulose formation, by implementing various spectral interpretation strategies of both multivariate principal component analysis (PCA) and 1-, 2- or 3-band/-variable intensity or intensity ratios. The main objective of this study was to compare the correlations between cellulose content determined by chemical analysis and ATR FT-IR spectral indices acquired by the reported procedures, among developmental Texas Marker-1 (TM-1) and immature fiber ( im ) mutant cotton fibers. It was observed that the R value, CI IR , and the integrated intensity of the 895 cm -1 band exhibited strong and linear relationships with cellulose content. The results have demonstrated the suitability and utility of ATR FT-IR spectroscopy, combined with a simple algorithm analysis, in assessing cotton fiber cellulose content, maturity, and crystallinity in a manner which is rapid, routine, and non-destructive.

  4. A Thermogravimetric Study of the Behaviour of Biomass Blends During Combustion

    Directory of Open Access Journals (Sweden)

    Ivo Jiříček

    2012-01-01

    Full Text Available The ignition and combustion behavior of biomass and biomass blends under typical heating conditions were investigated. Thermogravimetric analyses were performed on stalk and woody biomass, alone and blended with various additive weight ratios. The combustion process was enhanced by adding oxygen to the primary air. This led to shorter devolatilization/pyrolysis and char burnout stages, which both took place at lower temperatures than in air alone. The results of the ignition study of stalk biomass show a decrease in ignition temperature as the particle size decreases. This indicates homogeneous ignition, where the volatiles burn in the gas phase, preventing oxygen from reaching the particle surface.The behavior of biomass fuels in the burning process was analyzed, and the effects of heat production and additive type were investigated. Mixing with additives is a method for modifying biofuel and obtaining a more continuous heat release process. Differential scanning calorimetric-thermogravimetric (DSC-TGA analysis revealed that when the additive is added to biomass, the volatilization rate is modified, the heat release is affected, and the combustion residue is reduced at the same final combustion temperature.

  5. Thermogravimetric-Mass Spectrometric Study of the Pyrolysis Behavior of PVC

    Institute of Scientific and Technical Information of China (English)

    SUN Qing-lei; SHI Xin-gang; LIN Yun-liang; ZHU He; WANG Xiao; CHENG Chuan-ge; LIU Jian-hua

    2007-01-01

    The pyrolysis characteristics of PVC were systematically investigated using a Netzschne TG thermo-balance coupled to a quadrupole mass spectrometer. The pyrolysis conditions were 0.1 MPa of Ar, a heating rate of 10 ℃/min and a final temperature of 1000 ℃. Both the thermogravimetric properties and the simultaneous evolution of gaseous products during pyrolysis were studied. The TG/DTG results showed that as the pyrolysis temperature increases the weight loss and weight loss rate of PVC increases. Near 412 ℃ the weight loss rate attained its peak value. At higher temperatures the rate of loss gradually decreases. The gases evolved during thermogravimetric analysis were analyzed by a mass spectrometer, monitoring the relative intensity of HCl, C6H6, light hydrocarbon and chlorine-containing gases. The evolution curves showed that HCl, C6H6, light hydrocarbon and chlorine-containing gases all peak at about 416 ℃. This is consistent with the fact that the weight loss curves also peak at about 412 ℃. The extensive HCl evolution is consistent with the high chlorine content of PVC. The formation of these gases can be explained by considering these reactions: dehydrochlorination, intramolecular cyclization and the addition of HCl to unsaturated hydrocarbons.

  6. Isolated Gramicidin Peptides Probed by IR Spectroscopy

    NARCIS (Netherlands)

    Rijs, A. M.; Kabelac, M.; Abo-Riziq, A.; Hobza, P.; de Vries, M. S.

    2011-01-01

    We report double-resonant IR/UV ion-dip spectroscopy of neutral gramicidin peptides in the gas phase. The IR spectra of gramicidin A and C, recorded in both the 1000 cm(-1) to 1800 cm(-1) and the 2700 to 3750 cm(-1) region, allow structural analysis. By studying this broad IR range, various local

  7. Thermogravimetric investigation of the co-combustion between the pyrolysis oil distillation residue and lignite.

    Science.gov (United States)

    Li, Hao; Xia, Shuqian; Ma, Peisheng

    2016-10-01

    Co-combustion of lignite with distillation residue derived from rice straw pyrolysis oil was investigated by non-isothermal thermogravimetric analysis (TGA). The addition of distillation residue improved the reactivity and combustion efficiency of lignite, such as increasing the weight loss rate at peak temperature and decreasing the burnout temperature and the total burnout. With increasing distillation residue content in the blended fuels, the synergistic interactions between distillation residue and lignite firstly increased and then decreased during co-combustion stage. Results of XRF, FTIR, (13)C NMR and SEM analysis indicated that chemical structure, mineral components and morphology of samples have great influence on the synergistic interactions. The combustion mechanisms and kinetic parameters were calculated by the Coats Redfern model, suggesting that the lowest apparent activation energy (120.19kJ/mol) for the blended fuels was obtained by blending 60wt.% distillation residue during main co-combustion stage. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Identification of Serine Conformers by Matrix-Isolation IR Spectroscopy Aided by Near-Infrared Laser Induced Conformational Change, 2D Correlation Analysis, and Quantum Mechanical Anharmonic Computations

    Science.gov (United States)

    Najbauer, Eszter E.; Bazsó, Gábor; Apóstolo, Rui; Fausto, Rui; Biczysko, Malgorzata; Barone, Vincenzo; Tarczay, György

    2018-01-01

    The conformers of α-serine were investigated by matrix-isolation IR spectroscopy combined with NIR laser irradiation. This method, aided by 2D correlation analysis, enabled unambiguously grouping the spectral lines to individual conformers. On the basis of comparison of at least nine experimentally observed vibrational transitions of each conformer with empirically scaled (SQM) and anharmonic (GVPT2) computed IR spectra, 6 conformers were identified. In addition, the presence of at least one more conformer in Ar matrix was proved, and a short-lived conformer with a half-live of (3.7±0.5)·103 s in N2 matrix was generated by NIR irradiation. The analysis of the NIR laser induced conversions revealed that the excitation of the stretching overtone of both the side-chain and the carboxylic OH groups can effectively promote conformational changes, but remarkably different paths were observed for the two kinds of excitations. PMID:26201050

  9. The TX-model - a quantitative heat loss analysis of district heating pipes by means of IR surface temperature measurements

    Energy Technology Data Exchange (ETDEWEB)

    Zinki, Heimo [ZW Energiteknik, Nykoeping (Sweden)

    1996-11-01

    The aim of this study was to investigate the possibility of analysing the temperature profile at the ground surface above buried district heating pipes in such a way that would enable the quantitative determination of heat loss from the pair of pipes. In practical applications, it is supposed that this temperature profile is generated by means of advanced IR-thermography. For this purpose, the principle of the TX - model has been developed, based on the fact that the heat losses from pipes buried in the ground have a temperature signature on the ground surface. Qualitative analysis of this temperature signature is very well known and in practical use for detecting leaks from pipes. These techniques primarily make use of relative changes of the temperature pattern along the pipe. In the quantitative heat loss analysis, however, it is presumed that the temperature profile across the pipes is related to the pipe heat loss per unit length. The basic idea is that the integral of the temperature profile perpendicular to the pipe, called TX, is a function of the heat loss, but is also affected by other parameters such as burial depth, heat diffusivity, wind, precipitation and so on. In order to analyse the parameters influencing the TX- factor, a simulation model for the energy balance at the ground surface has been developed. This model includes the heat flow from the pipe to the surface and the heat exchange at the surface with the environment due to convection, latent heat change, solar and long wave radiation. The simulation gives the surprising result that the TX factor is by and large unaffected during the course of a day even when the sun is shining, as long as other climate conditions are relatively stable (low wind, no rain, no shadows). The results from the simulations were verified at different sites in Denmark, Finland, Sweden and USA through a co-operative research program organised and partially financed by the IEA District Heating Programme, Task III, and

  10. FT-IR-cPAS—New Photoacoustic Measurement Technique for Analysis of Hot Gases: A Case Study on VOCs

    Science.gov (United States)

    Hirschmann, Christian Bernd; Koivikko, Niina Susanna; Raittila, Jussi; Tenhunen, Jussi; Ojala, Satu; Rahkamaa-Tolonen, Katariina; Marbach, Ralf; Hirschmann, Sarah; Keiski, Riitta Liisa

    2011-01-01

    This article describes a new photoacoustic FT-IR system capable of operating at elevated temperatures. The key hardware component is an optical-readout cantilever microphone that can work up to 200 °C. All parts in contact with the sample gas were put into a heated oven, incl. the photoacoustic cell. The sensitivity of the built photoacoustic system was tested by measuring 18 different VOCs. At 100 ppm gas concentration, the univariate signal to noise ratios (1σ, measurement time 25.5 min, at highest peak, optical resolution 8 cm−1) of the spectra varied from minimally 19 for o-xylene up to 329 for butyl acetate. The sensitivity can be improved by multivariate analyses over broad wavelength ranges, which effectively co-adds the univariate sensitivities achievable at individual wavelengths. The multivariate limit of detection (3σ, 8.5 min, full useful wavelength range), i.e., the best possible inverse analytical sensitivity achievable at optimum calibration, was calculated using the SBC method and varied from 2.60 ppm for dichloromethane to 0.33 ppm for butyl acetate. Depending on the shape of the spectra, which often only contain a few sharp peaks, the multivariate analysis improved the analytical sensitivity by 2.2 to 9.2 times compared to the univariate case. Selectivity and multi component ability were tested by a SBC calibration including 5 VOCs and water. The average cross selectivities turned out to be less than 2% and the resulting inverse analytical sensitivities of the 5 interfering VOCs was increased by maximum factor of 2.2 compared to the single component sensitivities. Water subtraction using SBC gave the true analyte concentration with a variation coefficient of 3%, although the sample spectra (methyl ethyl ketone, 200 ppm) contained water from 1,400 to 100k ppm and for subtraction only one water spectra (10k ppm) was used. The developed device shows significant improvement to the current state-of-the-art measurement methods used in industrial

  11. Characterizing floodplain evolution by joint analysis of SAR, GOES IR and local precipitation data: Case study of Rio Colorado, Bolivia

    Science.gov (United States)

    Koenders, R.; Oyen, A. M.; Weltje, G.; Sarna, K.; Donselaar, R.

    2013-12-01

    Dryland rivers in an endorheic basin experience downstream decrease of channel width and depth as the consequence of transmission losses by percolation and evapo-transpiration. Major changes in the river morphology take place during short peak discharge periods when the volume of water and sediment by far exceeds the river capacity and, as a consequence, meander bends are cut off, and the river path may change position by avulsion. Successive avulsions create a complex network of cross-cutting abandoned river channels. The Río Colorado, located in the southeast part of the Altiplano basin in Bolivia, is such a river system. This system consists of a very low-gradient lacustrine coastal plain onto which is deposited a 400 km2 sheet of fluvial sediment over the last 4000 year. Traditional studies to monitor the morphological changes at the terminus of the river system are based on field data acquisition of the fluvial sediments. This is time consuming and only covers a small area of the total fluvial morphology. The combination of field measurements and remote sensing imagery allows for the analysis of the development of the entire river system terminus at a longer temporal scale. Changes of alluvial surfaces affect the reflectance of objects and patterns on the ground, which is recorded by satellite images. In this study we show the response of the delta to rainfall events of various intensities in the Rio Colorado watershed. We combine precipitation data in the watershed with spaceborne synthetic aperture radar (SAR) data. We use two data sets that contain precipitation information: rainfall estimates based on Geostationary Operational Environmental Satellite (GOES) weather satellite IR window brightness temperatures and direct measures of rainfall from rain gauges in the vicinity of the delta. To detect changes on the surface water content we use the backscatter intensity or amplitude images from the European Remote Sensing Satellite (ERS) Synthetic Aperture

  12. Identification of urushi coated films taken from ancient Buddha images by using PIXE, FT-IR, and organic elemental analysis

    International Nuclear Information System (INIS)

    Kagemori, N.; Umemura, K.; Yoshimura, T.; Inoue, M.; Kawai, S.; Yano, K.; Sera, K.; Futatsugawa, S.; Nakamura, Y.

    1999-01-01

    Six types of samples including urushi, urushi tree and black coating films taken from ancient Buddha images were examined by analyses of PIXE, organic element and FT-IR to identify with urushi or another material. Based on the results of three analytical experiments above mentioned, the coating materials aging over hundreds of years were identified with weathered urushi films mixed with other material. Further investigation may reveal the urushi coating techniques used in the past. (author)

  13. GC-MS and FI-IR analysis of the bio-oil with addition of ethyl acetate during storage

    Directory of Open Access Journals (Sweden)

    Le eZhang

    2014-01-01

    Full Text Available Different mass fractions (0%, 3%, 6%, 9%, 12%, and 15% of ethyl acetate were added to bio-oil for improving its storage stability during storage at 40℃ for 35d. For different bio-oils during storage, physical properties were characterized and chemical components were determined by GC-MS and FT-IR. The results of properties characterization showed that, addition of ethyl acetate could instantly lower bio-oil viscosity, water content, and dramatically decrease the rate of aging. pH value of bio-oil can be instantly improved by adding ethyl acetate. GC-MS results revealed that addition of various content of ethyl acetate into bio-oil and its storage at 40℃ for 35d could both lead to disappearance of previous compounds and generation of new compounds. FT-IR results showed that addition of various content of ethyl acetate into bio-oils and its storage at 40℃ for 35d could slightly change the wavenumbers of substantial functional groups in bio-oils.

  14. Imaging of lipids in atherosclerotic lesion in aorta from ApoE/LDLR-/- mice by FT-IR spectroscopy and Hierarchical Cluster Analysis.

    Science.gov (United States)

    P Wrobel, Tomasz; Mateuszuk, Lukasz; Chlopicki, Stefan; Malek, Kamilla; Baranska, Malgorzata

    2011-12-21

    Spectroscopy-based approaches can provide an insight into the biochemical composition of a tissue sample. In the present work Fourier transform infrared (FT-IR) spectroscopy was used to develop a reliable methodology to study the content of free fatty acids, triglycerides, cholesteryl esters as well as cholesterol in aorta from mice with atherosclerosis (ApoE/LDLR(-/-) mice). In particular, distribution and concentration of palmitic, oleic and linoleic acid derivatives were analyzed. Spectral analysis of pure compounds allowed for clear discrimination between free fatty acids and other similar moieties based on the carbonyl band position (1699-1710 cm(-1) range). In order to distinguish cholesteryl esters from triglycerides a ratio of carbonyl band to signal at 1010 cm(-1) was used. Imaging of lipids in atherosclerotic aortic lesions in ApoE/LDLR(-/-) mice was followed by Hierarchical Cluster Analysis (HCA). The aorta from C57Bl/6J control mice (fed with chow diet) was used for comparison. The measurements were completed with an FT-IR spectrometer equipped with a 128 × 128 FPA detector. In cross-section of aorta from ApoE/LDLR(-/-) mice a region of atherosclerotic plaque was clearly identified by HCA, which was later divided into 2 sub-regions, one characterized by the higher content of cholesterol, while the other by higher contents of cholesteryl esters. HCA of tissues deposited on normal microscopic glass, hence limited to the 2200-3800 cm(-1) spectral range, also identified a region of atherosclerotic plaque. Importantly, this region correlates with the area stained by standard histological staining for atherosclerotic plaque (Oil Red O). In conclusion, the use of FT-IR and HCA may provide a novel tool for qualitative and quantitative analysis of contents and distribution of lipids in atherosclerotic plaque.

  15. Multivariate analysis of attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopic data to confirm phase partitioning in methacrylate-based dentin adhesive.

    Science.gov (United States)

    Ye, Qiang; Parthasarathy, Ranganathan; Abedin, Farhana; Laurence, Jennifer S; Misra, Anil; Spencer, Paulette

    2013-12-01

    Water is ubiquitous in the mouths of healthy individuals and is a major interfering factor in the development of a durable seal between the tooth and composite restoration. Water leads to the formation of a variety of defects in dentin adhesives; these defects undermine the tooth-composite bond. Our group recently analyzed phase partitioning of dentin adhesives using high-performance liquid chromatography (HPLC). The concentration measurements provided by HPLC offered a more thorough representation of current adhesive performance and elucidated directions to be taken for further improvement. The sample preparation and instrument analysis using HPLC are, however, time-consuming and labor-intensive. The objective of this work was to develop a methodology for rapid, reliable, and accurate quantitative analysis of near-equilibrium phase partitioning in adhesives exposed to conditions simulating the wet oral environment. Analysis by Fourier transform infrared (FT-IR) spectroscopy in combination with multivariate statistical methods, including partial least squares (PLS) regression and principal component regression (PCR), were used for multivariate calibration to quantify the compositions in separated phases. Excellent predictions were achieved when either the hydrophobic-rich phase or the hydrophilic-rich phase mixtures were analyzed. These results indicate that FT-IR spectroscopy has excellent potential as a rapid method of detection and quantification of dentin adhesives that experience phase separation under conditions that simulate the wet oral environment.

  16. OH/IR stars in the Galaxy

    International Nuclear Information System (INIS)

    Baud, B.

    1978-01-01

    Radio astronomical observations leading to the discovery of 71 OH/IR sources are described in this thesis. These OH/IR sources are characterized by their double peaked OH emission profile at a wavelength of 18 cm and by their strong IR infrared emission. An analysis of the distribution and radial velocities of a number of previously known and new OH/IR sources was performed. The parameter ΔV (the velocity separation between two emission peaks of the 18 cm line profile) was found to be a good criterion for a population classification with respect to stellar age

  17. Characterization of microalga Chlorella as a fuel and its thermogravimetric behavior

    International Nuclear Information System (INIS)

    Rizzo, Andrea Maria; Prussi, Matteo; Bettucci, Lorenzo; Libelli, Ilaria Marsili; Chiaramonti, David

    2013-01-01

    Highlights: ► Proximate and ultimate analysis of two microalgae (Nannochloropsis and Chlorella spp.). ► TGA of Chlorella spp. and Nannochloropsis investigated at 15 °C/min up to 800 °C. ► 1.2 kg of Chlorella pyrolyzed in a novel batch, intermediate pyrolysis pilot reactor at 450 °C. ► Bio-oil from Chlorella oil analysed and compared to pine chips fast pyrolysis oil. ► Bio-oil from Chlorella exhibited superior properties compared to lignocellulosic pyrolysis oil as intermediate energy carrier. -- Abstract: Microalgae are photosynthetic microorganisms living in marine or freshwater environment. In this study, samples of Chlorella spp. and Nannochloropsis from two different origins were analysed to settle a preliminary characterization of these microorganisms as intermediate energy carriers and their properties compared to a conventional lignocellulosic feedstock (pine chips). Both microalgae samples were characterized in terms of elemental composition (CHONS and P) and thermogravimetric behavior. This was investigated through non-isothermal thermogravimetric analysis in nitrogen atmosphere at heating rate of 15 °C min −1 and temperature up to 800 °C. Solid residues produced at 300 °C and 800 °C from TGA were also analysed to determine the ultimate composition of chars. Activation energy, reaction order and pre-exponential factor were calculated for the single step conversion mechanism of 1 g of Chlorella spp. and compared to literature data on Chlorella protothecoides and Spirulina platensis. Calculated kinetic parameters, given as intervals of several determinations, resulted to be: pre-exponential factor (A) 1.47–1.62E6 min −1 , activation energy (E) 7.13–7.92E4 J mol −1 , reaction order (n) 1.69–2.41. 1.2 kg of Chlorella spp. was then processed in a newly designed batch pyrolysis pilot reactor, capable of converting up to 1.5 kg h −1 of material, and pyrolysis liquid collected, analysed and compared with a sample of fast pyrolysis

  18. Thermogravimetric studies of the thermo-oxidative stability of irradiated and unirradiated polyethylene

    International Nuclear Information System (INIS)

    Novakovic, L.; Gal, O.; Markovic, V.; Stannett, V.T.

    1985-01-01

    In part one of this series the effects of a phenolic, an amine and a thioester antioxidant on the thermo-oxidative stability of irradiated and unirradiated low-density polyethylene was reported. In this paper the effects of combined phenolic and thioester stabilizers are described. Isothermal thermogravimetric analysis was used to study the systems. Pronounced synergism was observed with the induction periods, the time when the initial weight loss begins and the 5% weight loss. At about 50% of each stabilizer increases greater than twofold were observed both with the unirradiated and irradiated polymers. The rate constants for oxygen uptake were decreased. However, the rates of degradation at 5% weight loss fell between the values of the two pure stabilizers with no pronounced synergism in either case. In the absence of oxygen little effect of either antioxidant or their mixtures was observed. The corresponding activation energies were somewhat higher, however, with the irradiated samples containing antioxidants. Dynamic thermogravimetry was used for this study. A kinetic analysis indicated that there were somewhat different modes of degradation at lower- and higher-temperature ranges. (author)

  19. Thermogravimetric studies of the thermo-oxidative stability of irradiated and unirradiated polyethylene. 2. Combined antioxidants

    Energy Technology Data Exchange (ETDEWEB)

    Novakovic, L; Gal, O; Markovic, V; Stannett, V T

    1985-01-01

    In part one of this series the effects of a phenolic, an amine and a thioester antioxidant on the thermo-oxidative stability of irradiated and unirradiated low-density polyethylene was reported. In this paper the effects of combined phenolic and thioester stabilizers are described. Isothermal thermogravimetric analysis was used to study the systems. Pronounced synergism was observed with the induction periods, the time when the initial weight loss begins and the 5% weight loss. At about 50% of each stabilizer increases greater than twofold were observed both with the unirradiated and irradiated polymers. The rate constants for oxygen uptake were decreased. However, the rates of degradation at 5% weight loss fell between the values of the two pure stabilizers with no pronounced synergism in either case. In the absence of oxygen little effect of either antioxidant or their mixtures was observed. The corresponding activation energies were somewhat higher, however, with the irradiated samples containing antioxidants. Dynamic thermogravimetry was used for this study. A kinetic analysis indicated that there were somewhat different modes of degradation at lower- and higher-temperature ranges. (author).

  20. Physicotechnical, spectroscopic and thermogravimetric properties of powdered cellulose and microcrystalline cellulose derived from groundnut shells

    Directory of Open Access Journals (Sweden)

    Chukwuemeka P. Azubuike

    2012-09-01

    Full Text Available α-Cellulose and microcrystalline cellulose powders, derived from agricultural waste products, that have for the pharmaceutical industry, desirable physical (flow properties were investigated. α–Cellulose (GCN was extracted from groundnut shell (an agricultural waste product using a non-dissolving method based on inorganic reagents. Modification of this α -cellulose was carried out by partially hydrolysing it with 2N hydrochloric acid under reflux to obtain microcrystalline cellulose (MCGN. The physical, spectroscopic and thermal properties of the derived α-cellulose and microcrystalline cellulose powders were compared with Avicel® PH 101, a commercial brand of microcrystalline cellulose (MCCA, using standard methods. X-ray diffraction and infrared spectroscopy analysis showed that the α-cellulose had lower crystallinity. This suggested that treatment with 2N hydrochloric acid led to an increase in the crystallinity index. Thermogravimetric analysis showed quite similar thermal behavior for all cellulose samples, although the α-cellulose had a somewhat lower stability. A comparison of the physical properties between the microcrystalline celluloses and the α-cellulose suggests that microcrystalline cellulose (MCGN and MCCA might have better flow properties. In almost all cases, MCGN and MCCA had similar characteristics. Since groundnut shells are agricultural waste products, its utilization as a source of microcrystalline cellulose might be a good low-cost alternative to the more expensive commercial brand.

  1. 2DCOS and PCMW2D analysis of FT-IR/ATR spectra measured at variable temperatures on-line to a polyurethane polymerization

    Science.gov (United States)

    Schuchardt, Patrick; Unger, Miriam; Siesler, Heinz W.

    2018-01-01

    In the present communication the potential of 2DCOS analysis and the spin-off technique perturbation-correlation moving window 2D (PCMW2D) analysis is illustrated with reference to spectroscopic changes observed in a data set recorded by in-line fiber-coupled FT-IR spectroscopy in the attenuated total reflection (ATR) mode during a polyurethane solution polymerization at different temperatures. In view of the chemical functionalities involved, hydrogen bonding plays an important role in this polymerization reaction. Based on the 2DCOS and PCMW2D analysis, the sequence of hydrogen bonding changes accompanying the progress of polymerization and precipitation of solid polymer can be determined. Complementary to the kinetic data derived from the original variable-temperature spectra in a previous publication the results provide a more detailed picture of the investigated solution polymerization.

  2. IOT Overview: IR Instruments

    Science.gov (United States)

    Mason, E.

    In this instrument review chapter the calibration plans of ESO IR instruments are presented and briefly reviewed focusing, in particular, on the case of ISAAC, which has been the first IR instrument at VLT and whose calibration plan served as prototype for the coming instruments.

  3. A novel frequency analysis method for assessing K(ir)2.1 and Na (v)1.5 currents.

    Science.gov (United States)

    Rigby, J R; Poelzing, S

    2012-04-01

    Voltage clamping is an important tool for measuring individual currents from an electrically active cell. However, it is difficult to isolate individual currents without pharmacological or voltage inhibition. Herein, we present a technique that involves inserting a noise function into a standard voltage step protocol, which allows one to characterize the unique frequency response of an ion channel at different step potentials. Specifically, we compute the fast Fourier transform for a family of current traces at different step potentials for the inward rectifying potassium channel, K(ir)2.1, and the channel encoding the cardiac fast sodium current, Na(v)1.5. Each individual frequency magnitude, as a function of voltage step, is correlated to the peak current produced by each channel. The correlation coefficient vs. frequency relationship reveals that these two channels are associated with some unique frequencies with high absolute correlation. The individual IV relationship can then be recreated using only the unique frequencies with magnitudes of high absolute correlation. Thus, this study demonstrates that ion channels may exhibit unique frequency responses.

  4. Ft-Ir Spectroscopic Analysis of Potsherds Excavated from the First Settlement Layer of Kuriki Mound, Turkey

    Science.gov (United States)

    Bayazit, Murat; Isik, Iskender; Cereci, Sedat; Issi, Ali; Genc, Elif

    The region covering Southeastern Anatolia takes place in upper Mesopotamia, so it has numerous cultural heritages due to its witness to various social movements of different civilizations in ancient times. Kuruki Mound is located on the junction point of Tigris River and Batman Creek, near Oymatas village which is almost 15 km to Batman, Turkey. The mound is dated back to Late Chalcolithic. Archaeological excavations are carried out on two hills named as “Kuriki Mound-1” and “Kuriki Mound-2” in which 4-layer and 2-layer settlements have been revealed, respectively. This region will be left under the water by the reservoir lake of Ilısu Dam when its construction is completed. Thus, characterization of ancient materials such as potsherds, metals and skeleton ruins should be rapidly done. In this study, 12 potsherds excavated from Layer-1 (the first settlement layer after the surface) in Kuriki Mound-2 were investigated by FT-IR spectrometry. Energy dispersive X-ray fluorescence (EDXRF) and X-ray diffraction (XRD) analyses were used as complementary techniques in order to expose chemical and mineralogical/phase contents, respectively. Obtained results showed that the potteries have been produced with calcareous clays and they include moderate amounts of MgO, K2O, Na2O and Fe2O3 in this context. Additionally, high temperature phases have also been detected with XRD analyses in some samples.

  5. Thermogravimetric study of a Phase Change Slurry: Effect of variable conditions

    International Nuclear Information System (INIS)

    Giro-Paloma, J.; Valle-Zermeño, R. del; Fernández, A.I.; Chimenos, J.M.; Formosa, J.

    2016-01-01

    Highlights: • Dry or wet PCS present differences in their thermal behavior. • The optimum conditions of dry PCS were determined by TGA. • Type of atmosphere and heating rate were the variables under consideration. • T peak can be accurately determined at 1 °C·min −1 in N 2. • Fusion/latent heat can be best determined at 10 °C·min −1 . - Abstract: Microcapsules containing Phase Change Materials (MPCM) are widely used for passive systems in energy storage. When MPCM are mixed with a carrier fluid, Phase Change Slurries (PCS) are used for heat transfer fluids in active systems or heat transport systems. The thermal behavior of PCS can be measured as dry or wet basis, resulting in important differences in weight losses. This study explores the optimum conditions for analyzing the thermal behavior of dried PCS by thermogravimetric analysis (TGA) varying the parameter conditions for obtaining peak temperature and heat flow (latent heat). The factors that were taken into account were the atmosphere of study (air and nitrogen) and the heating rate (0.5, 1, 5, and 10 °C·min −1 ). The best conditions to determine peak temperature are at 1 °C·min −1 and in N 2 atmosphere, whereas the decomposition fusion/latent heat of the sample is improved at higher heating velocities towards 10 °C·min −1 .

  6. Thermogravimetric study of the kinetics of lithium titanate reduction by hydrogen

    International Nuclear Information System (INIS)

    Sonak, Sagar; Rakesh, R.; Jain, Uttam; Mukherjee, Abhishek; Kumar, Sanjay; Krishnamurthy, Nagaiyar

    2014-01-01

    Highlights: • Li 2 TiO 3 powder is synthesized by the gel combustion route. • Activation energy of reduction of Li 2 TiO 3 by H 2 found out to be 27.45 kJ/mol H 2 . • Non-stoichiometric phase of Li 2 TiO 3 is formed in hydrogen atmosphere. • One-dimensional diffusion appears to be the most probable mechanism of reduction. - Abstract: The lithium titanate powder was synthesized by gel-combustion route. The mechanism and the kinetics of hydrogen interaction with lithium titanate powder were studied using non-isothermal thermogravimetric technique. Lithium titanate underwent reduction in hydrogen atmosphere which led to the formation of oxygen deficient non-stoichiometric compound in lithium titanate. One-dimensional diffusion appeared to be the most probable reaction mechanism. The activation energy for reduction of lithium titanate under hydrogen atmosphere was found to be 27.4 kJ/mol/K. Structural changes after hydrogen reduction in lithium titanate were observed in X-ray diffraction analysis

  7. Thermogravimetric-mass spectrometric study on the evolution of nitrogen compounds during coal devolatilisation

    Energy Technology Data Exchange (ETDEWEB)

    Arenillas, A.; Rubiera, F.; Pevida, C.; Pis, J.J. [Department of Energy and Environment, Instituto Nacional del Carbon, CSIC, Apartado 73, 33080 Oviedo (Spain)

    2002-10-01

    Emissions of nitrogen oxides during coal combustion are a major environmental problem. The chemically bound nitrogen in fuel accounts for up to 80% of total NO{sub x} emissions. In this respect, fundamental studies are needed to clarify the mechanisms and to identify the different species that are precursors in the formation of the NO{sub x}. Mass spectrometry (MS) has been used for decades as a successful technique in evolved gas analysis. However, MS is normally used to identify typical volatile compounds formed during coal pyrolysis (i.e. H{sub 2}, CH{sub 4}, CO, CO{sub 2} and H{sub 2}O) but very few works on the detection by MS of nitrogen compounds during coal devolatilisation can be found. In this work, the possibility of detecting different nitrogen compounds by means of thermogravimetric-MS during the temperature-programmed pyrolysis of coal was evaluated. Interferences in the N-compounds MS signals were determined. The use of model compounds provided additional information on the MS response factors of the volatile compounds produced.

  8. Thermogravimetric studies on alkyl methacrylate polymers and poly(alkyl methacrylate)-grafted polypropylene fibers

    International Nuclear Information System (INIS)

    Hayakawa, Kiyoshi; Taoda, Hiroshi; Kawase, Kaoru; Tazawa, Masato; Yamakita, Hiromi

    1986-01-01

    Thermal behavior of several kinds of poly (alkyl methacrylate) and polypropylene-g-poly (alkyl methacrylate) fibers prepared by γ-irradiation was investigated by thermogravimetric measurements with the intermittent analysis of the gaseous products. The degradation of poly (methyl methacrylate) proceeded according to the deploymerization mechanism reproducing the pristine monomer exclusively. The thermogram in inert atmosphere showed the features of a two-step depolymerization, while in air it showed no such a stepwise decrease with the elevating temperature. The dissolution-precipitation treatment of polymer seemed to affect the decomposition behavior. On other alkyl methacrylate polymers, the thermal decomposition generally proceeded also according to the depolymerization mechanism. But, for instance, at least two kinds of products besides its own monomer were formed from poly (isobutyl methacrylate), and their relative fractions differed with the temperature. Polypropylene-g-poly (alkyl methacrylate) fibers showed lowering of initiation temperature of decomposition with the increase in extent of the grafting, and their initiation temperatures of decomposition in air were lower than those in inert atmosphere. (author)

  9. Thermogravimetric investigation on the degradation properties and combustion performance of bio-oils.

    Science.gov (United States)

    Ren, Xueyong; Meng, Jiajia; Moore, Andrew M; Chang, Jianmin; Gou, Jinsheng; Park, Sunkyu

    2014-01-01

    The degradation properties and combustion performance of raw bio-oil, aged bio-oil, and bio-oil from torrefied wood were investigated through thermogravimetric analysis. A three-stage process was observed for the degradation of bio-oils, including devolatilization of the aqueous fraction and light compounds, transition of the heavy faction to solid, and combustion of carbonaceous residues. Pyrolysis kinetics parameters were calculated via the reaction order model and 3D-diffusion model, and combustion indexes were used to qualitatively evaluate the thermal profiles of tested bio-oils for comparison with commercial oils such as fuel oils. It was found that aged bio-oil was more thermally instable and produced more combustion-detrimental carbonaceous solid. Raw bio-oil and bio-oil from torrefied wood had comparable combustion performance to fuel oils. It was considered that bio-oil has a potential to be mixed with or totally replace the fuel oils in boilers. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Pyrolysis of olive residue/low density polyethylene mixture:Part I Thermogravimetric kinetics

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This paper demonstrates the thermal pyrolysis of olive residue, low density polyethylene (LDPE) and olive residue/LDPE mixture in an inert atmosphere of N2 using thermogravimetric analysis (TGA). Measurements were carried out in the temperature range 300K~973K at heating rates of 2K/min, 10K/min, 20K/min and 50K/min. Based on the results obtained, three temperature regimes were selected for studying the non-isothermal kinetics of olive residue/LDPE mixture. The first two were dominated by the olive residue pyrolysis, while the third was linked to the LDPE pyrolysis, which occurred at much higher temperatures. Discrepancies between the experimental and calculated TG/DTG profiles were considered as a measurement of the extent of interactions occurring on co-pyrolysis. The maximum degradation temperatures of each component in the mixture were higher than those the individual components;thus an increase in thermal stability was expected. The kinetic parameters associated with thermal degradation were determined using Friedman isoconversional method.

  11. Thermogravimetric Studies of Deposited Potash Impregnated for Flame-Retardancy into a Cotton Fabric

    Institute of Scientific and Technical Information of China (English)

    MOSTASHARI, S.M.; NIA, Y.K.; BAIE, S.

    2007-01-01

    The effect of potash as a nondurable finish on the flammability of 100% cotton fabric (plain 180 g/m2) was investigated. The bone-dried weighed fabrics were dipped into suitable concentrations of potash, with a volume of 100 mL at 20-2 ℃. The impregnation was followed by means of squeeze rolls and drying at 110 C. The samples were then reweighed with analytical precision. After conditioning overnight by using our "vertical flame tester" the optimum add-on values to impart flame-retardancy to cotton fabric was determined and expressed by 0.80 g of potash per 100 g fabric to be an efficient addition. Thermogravimetric analysis of pure cotton, treated cotton with potash at its optimum efficiency for donation of flame-retardancy into cotton fabric was fulfilled and the thermograms were compared and commented. The effectiveness of this hydroxide was attributed to the heat dissipation by the remaining consumed material during the combustion. The results obtained are in favor of "Dust or Wall Effect Theory".

  12. CORRELATION ANALYSIS OF IR, 1 H- AND 13 C-NMR SPECTRAL DATA OF N-ALKYL AND N-CYCLOALKYL CYANOACETAMIDES

    Directory of Open Access Journals (Sweden)

    Aleksandar D. Marinković

    2011-09-01

    Full Text Available Linear free energy relationships (LFER were applied to the IR, 1H- and 13C--NMR spectral data in N-alkyl and N-cycloalkyl cyanoacetamides. N-alkyl and N-cycloalkyl cyanocetamides were synthesized from corresponding amine and ethyl cyanoacetate. A number of substituents were employed for alkyl substitution, and fairly good correlations were obtained, using simple Hammett equation. In N-alkyl and N-cycloalkyl cyanoacetamides substituent cause SCS of N-H hydrogen primarily by steric interaction, polar subtituent effect influences SCS shift of C=O carbon, while steric effect of N-alkyl substituent causes IR stretching frequencies of N-H, C=O and CN group. The conformations of investigated compounds have been studied by the use of semiempirical PM6 method, and together with LFER analysis, give a better insight into the influence of such a structure on the transmission of electronic substituent effects. Negative ρ values for several correlations (reverse substituent effect were found.

  13. Vibrational spectra (FT-IR, FT-Raman), frontier molecular orbital, first hyperpolarizability, NBO analysis and thermodynamics properties of Piroxicam by HF and DFT methods

    Science.gov (United States)

    Suresh, S.; Gunasekaran, S.; Srinivasan, S.

    2015-03-01

    The solid phase FT-IR and FT-Raman spectra of 4-Hydroxy-2-methyl-N-(2-pyridinyl)-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide (Piroxicam) have been recorded in the region 4000-400 and 4000-100 cm-1 respectively. The molecular geometry, harmonic vibrational frequencies and bonding features of piroxicam in the ground state have been calculated by Hartree-Fock (HF) and density functional theory (DFT) methods using 6-311++G(d,p) basis set. The calculated harmonic vibrational frequencies are scaled and they are compared with experimental obtained by FT-IR and FT-Raman spectra. A detailed interpretation of the vibrational spectra of the title compound has been made on the basis of the calculated potential energy distribution (PED). The electronic properties, such as HOMO and LUMO energies, molecular electrostatic potential (MESP) are also performed. The linear polarizability (α) and the first order hyper polarizability (β) values of the title compound have been computed. The molecular stability arising from hyper conjugative interaction, charge delocalization has been analyzed using natural bond orbital (NBO) analysis.

  14. Molecular structure, vibrational spectroscopic analysis (IR & Raman), HOMO-LUMO and NBO analysis of anti-cancer drug sunitinib using DFT method

    Science.gov (United States)

    Mıhçıokur, Özlem; Özpozan, Talat

    2017-12-01

    Oxindole and its derivatives have wide applications in different industries such as in synthetic & natural fibers, dyes for hair and plastic materials in addition to their biological importance. In the present study, one of the oxindole derivatives, N-(2-diethylaminoethyl)-5-[(Z)-(5-fluoro-2-oxo-1H-indol-3-ylidene)methyl]-2,4-dimethyl-1H-pyrrole-3-carboxamide (Sunitinib), which is used as an anti-cancer drug, was investigated in terms of structural, vibrational spectroscopic and theoretical analysis. The calculations have been performed for gaseous, aqueous and DMSO phases, respectively. Potential Energy Surface (PES) scan has been carrried out to obtain the most stable structures of all the phases of the title molecule using B3LYP/6-31G(d,p) level and the geometrical variations among them are discussed. The solvent effect for Sunitinib in aqueous and DMSO phases have been performed by means of the self-consistent recognition reaction field (SCRF) method as implemented in the integral equation formalism polarized continuum model (IEFPCM). On the other hand, NBO analysis has been carried out to understand probable hydrogen bonding sites and charge transfers. Additionally, the HOMO and the LUMO energies are calculated using B3LYP/6-31G(d,p) to determine the intra molecular charge transfers (ICT) within the molecule and the kinetic stabilities for each phases. The molecular electrostatic potential surface (MESP) has been plotted over the optimized structure to estimate the reactive sites of electrophilic and nucleophilic attacks regarding Sunitinib molecule. The potential energy distribution (PED) has been calculated using VEDA4 program and vibrational assignments of the experimental spectra (IR & Raman) have been elucidated by means of the calculated vibrational spectra. The observed vibrational spectra of Sunitinib is compared with the calculated spectra obtained by using B3LYP functional both with 6-31G(d,p) and 6-311++G(d,p) basis sets. Theoretical results

  15. Classification and structural analysis of live and dead salmonella cells using fourier transform infrared (FT-IR) spectroscopy and principle component analysis (PCA)

    Science.gov (United States)

    Fourier Transform Infrared Spectroscopy (FT-IR) was used to detect Salmonella typhimurium and Salmonella enteritidis foodborne bacteria and distinguish between live and dead cells of both serotypes. Bacteria were loaded individually on the ZnSe Attenuated Total Reflection (ATR) crystal surface and s...

  16. Effect of superfine grinding on the physico-chemical, morphological and thermogravimetric properties of Lentinus edodes mushroom powders.

    Science.gov (United States)

    Ming, Jian; Chen, Long; Hong, Hui; Li, Jinlong

    2015-09-01

    Lentinus edodes is an edible mushroom commonly known as shiitake, which is the second most produced and consumed edible mushroom in the world and is an important nutrient source in the human diet. To fully use L. edodes, the mushrooms are occasionally ground into powder as a flavourful and functional food additive. This study produces powders from the cap and stipe of Lentinus edodes mushrooms through superfine grinding. These powders are composed of sub-micron range particles with various size distributions. The superfine grinding process is then compared with shear pulverisation to determine the different effects on both the cap and stipe powders in terms of particle size and physico-chemical, morphological and thermogravimetric properties. When average particle size was reduced to 0.54 and 0.46 µm, respectively, the moisture and protein content, angles of repose and slide, and water holding capacity of the powders decreased to varied extents. However, soluble dietary fibre, water solubility index, and swelling capacity increased. Scanning electron microscope images suggested that the superfine grinding process effectively changed the original surface structure of the L. edodes powders. The curves of thermogravimetric analysis and those of the derivatives of thermogravimetry indicated that superfine grinding can improve the thermostability of L. edodes powders. Furthermore, superfinely ground L. edodes powders may be used as pharmaceutical or food additives in various fields. The present study suggests that superfinely ground L. edodes powders may be applied in various fields as pharmaceutical or food additives. © 2014 Society of Chemical Industry.

  17. Interpretation of Quasi-Isothermal Thermogravimetric Weight Curves

    DEFF Research Database (Denmark)

    Sørensen, Ole Toft

    1979-01-01

    Quasi-isothermal analysis (QIA) is a very useful technique. Compared to conventional non-isothermal thermogravimetry, close-lying reactions can easily be separated by use of this method and kinetic data can be obtained for each intermediate reaction in a single run. This paper discusses the shape...

  18. Spectroscopic investigation (FT-IR, FT-Raman), HOMO-LUMO, NBO, and molecular docking analysis of N-ethyl-N-nitrosourea, a potential anticancer agent

    Science.gov (United States)

    Singh, Priyanka; Islam, S. S.; Ahmad, Hilal; Prabaharan, A.

    2018-02-01

    Nitrosourea plays an important role in the treatment of cancer. N-ethyl-N-nitrosourea, also known as ENU, (chemical formula C3H7N3O2), is a highly potent mutagen. The chemical is an alkylating agent and acts by transferring the ethyl group of ENU to nucleobases (usually thymine) in nucleic acids. The molecular structure of N-ethyl-N-nitrosourea has been elucidated using experimental (FT-IR and FT-Raman) and theoretical (DFT) techniques. APT charges, Mulliken atomic charges, Natural bond orbital, Electrostatic potential, HOMO-LUMO and AIM analysis were performed to identify the reactive sites and charge transfer interactions. Furthermore, to evaluate the anticancer activity of ENU molecular docking studies were carried out against 2JIU protein.

  19. Conversion of Natural Aldehydes from Eucalyptus citriodora, Cymbopogon citratus, and Lippia multiflora into Oximes: GC-MS and FT-IR Analysis

    Directory of Open Access Journals (Sweden)

    Igor W. Ouédraogo

    2009-08-01

    Full Text Available Three carbonyl-containing extracts of essential oils from Eucalyptus citriodora (Myrtaceae, Cymbopogon citratus (Gramineae and Lippia multiflora (Verbenaceae were used for the preparation of oximes. The reaction mixtures were analyzed by GC-MS and different compounds were identified on the basis of their retention times and mass spectra. We observed quantitative conversion of aldehydes to their corresponding oximes with a purity of 95 to 99%. E and Z stereoisomers of the oximes were obtained and separated by GC-MS. During GC analysis, the high temperature in the injector was shown to cause partial dehydratation of oximes and the resulting nitriles were readily identified. Based on FT-IR spectroscopy, that revealed the high stability and low volatility of these compounds, the so-obtained oximes could be useful for future biological studies.

  20. Dominant thermogravimetric signatures of lignin in cashew shell as compared to cashew shell cake.

    Science.gov (United States)

    Gangil, Sandip

    2014-03-01

    Dominant thermogravimetric signatures related to lignin were observed in cashew shell as compared to these signatures in cashew shell cake. The phenomenon of weakening of lignin from cashew shell to cashew shell cake was explained on the basis of changes in the activation energies. The pertinent temperature regimes responsible for the release of different constituents of both the bio-materials were identified and compared. The activation energies of cashew shell and cashew shell cake were compared using Kissinger-Akahira-Sunose method. Thermogravimetric profiling of cashew shell and cashew shell cake indicated that these were different kinds of bio-materials. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. A meta-analysis of the effect of angiotensin receptor blockers and calcium channel blockers on blood pressure, glycemia and the HOMA-IR index in non-diabetic patients.

    Science.gov (United States)

    Yang, Yue; Wei, Ri-bao; Xing, Yue; Tang, Lu; Zheng, Xiao-yong; Wang, Zi-cheng; Gao, Yu-wei; Li, Min-xia; Chen, Xiang-mei

    2013-12-01

    This study compared the efficacy of angiotensin receptor blockers (ARBs) and calcium channel blockers (CCBs) in the effect of insulin resistance (IR) as assessed using the homeostasis model assessment of insulin resistance (HOMA-IR) in non-diabetic patients. The MEDLINE, EMBASE, and Cochrane Library databases were searched to identify studies published before December 2012 that investigated the use of ARBs and CCBs to determine the effect on the HOMA-IR index in non-diabetics. Parameters on IR and blood pressure were collected. Review Manager 5.2 and Stata 12.0 were used to perform the meta-analysis. Fixed and random effects models were applied to various aspects of the meta-analysis, which assessed the therapeutic effects of the two types of drug using the HOMA-IR index in non-diabetic patients. The meta-analysis included five clinical trials. Patient comparisons before and after treatment with ARBs and CCBs revealed that ARBs reduced the HOMA-IR index (weighted mean difference (WMD) -0.65, 95% confidence interval (CI) -0.93 to -0.38) and fasting plasma insulin (FPI) (WMD -2.01, 95% CI -3.27 to -0.74) significantly more than CCBs. No significant differences in the therapeutic effects of these two types of drug on blood pressure were observed. Given that there are no significant differences in the therapeutic effects of ARBs and CCBs on blood pressure, as ARBs are superior to CCBs in their effect on the HOMA-IR index in non-diabetics, they might be a better choice in hypertension patients without diabetes. © 2013.

  2. Thermogravimetric, Devolatilization Rate, and Differential Scanning Calorimetry Analyses of Biomass of Tropical Plantation Species of Costa Rica Torrefied at Different Temperatures and Times

    Directory of Open Access Journals (Sweden)

    Johanna Gaitán-Álvarez

    2018-03-01

    Full Text Available We evaluated the thermogravimetric and devolatilization rates of hemicellulose and cellulose, and the calorimetric behavior of the torrefied biomass, of five tropical woody species (Cupressus lusitanica, Dipteryx panamensis, Gmelina arborea, Tectona grandis and Vochysia ferruginea, at three temperatures (TT and three torrefaction times (tT using a thermogravimetric analyzer. Through a multivariate analysis of principal components (MAPC, the most appropriate torrefaction conditions for the different types of woody biomass were identified. The thermogravimetric analysis-derivative thermogravimetry (TGA-DTG analysis showed that a higher percentage of the hemicellulose component of the biomass degrades, followed by cellulose, so that the hemicellulose energy of activation (Ea was less than that of cellulose. With an increase in TT and tT, the Ea for hemicellulose decreased but increased for cellulose. The calorimetric analyses showed that hemicellulose is the least stable component in the torrefied biomass under severe torrefaction conditions, and cellulose is more thermally stable in torrefied biomass. From the MAPC results, the best torrefaction conditions for calorimetric analyses were at 200 and 225 °C after 8, 10, and 12 min, for light and middle torrefaction, respectively, for the five woody species.

  3. Sugar composition and FT-IR analysis of exopolysaccharides produced by microbial isolates from paper mill slime deposits

    NARCIS (Netherlands)

    Verhoef, R.P.; Schols, H.A.; Blanco, A.; Siika-aho, M.; Ratto, M.; Buchert, J.; Lenon, G.; Voragen, A.G.J.

    2005-01-01

    Thirty exopolysaccharides (EPS) produced by bacteria isolated from biofilms or slimelayers from different paper and board mills in Finland, France and Spain were subjected to size exclusion chromatography and sugar compositional analysis. High performance size exclusion chromatography (HPSEC)

  4. GHRSST Level 4 MW_IR_OI Global Foundation Sea Surface Temperature analysis (GDS versions 1 and 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) global Level 4 sea surface temperature analysis produced daily on a 0.81 degree grid at Remote Sensing...

  5. Application of PCA and SIMCA statistical analysis of FT-IR spectra for the classification and identification of different slag types with environmental origin.

    Science.gov (United States)

    Stumpe, B; Engel, T; Steinweg, B; Marschner, B

    2012-04-03

    In the past, different slag materials were often used for landscaping and construction purposes or simply dumped. Nowadays German environmental laws strictly control the use of slags, but there is still a remaining part of 35% which is uncontrolled dumped in landfills. Since some slags have high heavy metal contents and different slag types have typical chemical and physical properties that will influence the risk potential and other characteristics of the deposits, an identification of the slag types is needed. We developed a FT-IR-based statistical method to identify different slags classes. Slags samples were collected at different sites throughout various cities within the industrial Ruhr area. Then, spectra of 35 samples from four different slags classes, ladle furnace (LF), blast furnace (BF), oxygen furnace steel (OF), and zinc furnace slags (ZF), were determined in the mid-infrared region (4000-400 cm(-1)). The spectra data sets were subject to statistical classification methods for the separation of separate spectral data of different slag classes. Principal component analysis (PCA) models for each slag class were developed and further used for soft independent modeling of class analogy (SIMCA). Precise classification of slag samples into four different slag classes were achieved using two different SIMCA models stepwise. At first, SIMCA 1 was used for classification of ZF as well as OF slags over the total spectral range. If no correct classification was found, then the spectrum was analyzed with SIMCA 2 at reduced wavenumbers for the classification of LF as well as BF spectra. As a result, we provide a time- and cost-efficient method based on FT-IR spectroscopy for processing and identifying large numbers of environmental slag samples.

  6. Chemical and Pyrolytic Thermogravimetric Characterization of Nigerian Bituminous Coals

    Directory of Open Access Journals (Sweden)

    Nyakuma Bemgba Bevan

    2016-12-01

    Full Text Available The discovery of new coal deposits in Nigeria presents solutions for nation’s energy crises and prospects for socioeconomic growth and sustainable development. Furthermore, the quest for sustainable energy to limit global warming, climate change, and environmental degradation has necessitated the exploration of alternatives using cleaner technologies such as coal pyrolysis. However, a lack of comprehensive data on physico-chemical and thermal properties of Nigerian coals has greatly limited their utilization. Therefore, the physico-chemical properties, rank (classification, and thermal decomposition profiles of two Nigerian bituminous coals – Afuze (AFZ and Shankodi-Jangwa (SKJ – were examined in this study. The results indicate that the coals contain high proportions of C, H, N, S, O and a sufficiently high heating value (HHV for energy conversion. The coal classification revealed that the Afuze (AFZ coal possesses a higher rank, maturity, and coal properties compared to the Shankodi-Jangwa (SKJ coal. A thermal analysis demonstrated that coal pyrolysis in both cases occurred in three stages; drying (30-200 °C, devolatilization (200-600 °C, and char decomposition (600-1000 °C. The results also indicated that pyrolysis at 1000 °C is not sufficient for complete pyrolysis. In general, the thermochemical and pyrolytic fuel properties indicate that the coal from both places can potentially be utilized for future clean energy applications.

  7. Thermogravimetric and nuclear magnetic resonance study of hydrated Na-β''-alumina

    International Nuclear Information System (INIS)

    Donoso, P.; Panepucci, H.; Gobato, Y.G.; Oliveira, L.N.; Souza, D.P.F. de

    1990-01-01

    This paper reports thermogravimetric and proton spin-lattice relaxation times measurement of hydrated Na-β''-alumina, which yield information about the identification of the sites where the loosely bound water molecules are located in the polycrystalline sample. It examines also the influence of impurities on the motion of the protons. (autor) [pt

  8. Co-combustion characteristics and blending optimization of tobacco stem and high-sulfur bituminous coal based on thermogravimetric and mass spectrometry analyses.

    Science.gov (United States)

    Zhang, Kaihua; Zhang, Kai; Cao, Yan; Pan, Wei-ping

    2013-03-01

    Despite much research on co-combustion of tobacco stem and high-sulfur coal, their blending optimization has not been effectively found. This study investigated the combustion profiles of tobacco stem, high-sulfur bituminous coal and their blends by thermogravimetric analysis. Ignition and burnout performances, heat release performances, and gaseous pollutant emissions were also studied by thermogravimetric and mass spectrometry analyses. The results indicated that combustion of tobacco stem was more complicated than that of high-sulfur bituminous coal, mainly shown as fixed carbon in it was divided into two portions with one early burning and the other delay burning. Ignition and burnout performances, heat release performances, and gaseous pollutant emissions of the blends present variable trends with the increase of tobacco stem content. Taking into account the above three factors, a blending ratio of 0–20% tobacco stem content is conservatively proposed as optimum amount for blending. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Thermogravimetric characteristics and kinetics of scrap tyre and Juglans regia shell co-pyrolysis.

    Science.gov (United States)

    Uzun, B B; Yaman, E

    2014-10-01

    The degradation kinetics of Juglans regia shell, scrap tyre and their blends were investigated using a thermogravimetric analysis method. Experiments were performed under dynamic conditions and a nitrogen atmosphere in the range 293 to 973 K at different heating rates. During pyrolysis of J. regia shell three mass loss zones were specified as removal of water, decomposition of hemicelluloses and cellulose, and decomposition of lignin. The degradation curves of scrap tyre showed merely one stage which was due to decomposition of styrene butadiene rubber. The kinetic parameters were calculated using both Arrhenius and Coats-Redfern methods. By adopting the Arrhenius method, the average value of activation energies of J. regia shell, scrap tyre and their 1 : 1 blends were found to be 69.22, 71.48 and 47.03 kJ mol(-1), respectively. Additionally, by using the Coats-Redfern method, the average value of activation energies of J. regia shell, scrap tyre and their 1 : 1 blend were determined as 99.85, 78.72 and 63.81 kJ mol(-1), respectively. The addition of J. regia shell to scrap tyre caused a reduction in the activation energies. The difference of weight loss was measured to examine interactions between raw materials. The maximum difference between experimental and theoretical mass loss was 5% at about 648 K with a heating rate of 20 K min(-1). These results indicated a significant synergistic effect was available during co-pyrolysis of J. regia shell and scrap tyre in the high temperature region. © The Author(s) 2014.

  10. Protonation of benzimidazoles and 1,2,3-benzotriazoles Solid-state linear dichroic infrared (IR-LD) spectral analysis and ab initio calculations

    Science.gov (United States)

    Ivanova, Bojidarka B.; Pindeva, Liliya I.

    2006-09-01

    IR-LD spectroscopic data obtained by the orientated solid samples as a suspension in a nematic liquid crystal of 1-hydroxy-1,2,3-benzotriazole, 2-methyl-, 2-acetonitrilebenzimidazoles and their protonated salts have been presented. The stereo-structures have been predicted and compared with theoretical ones. The IR-characteristic bands assignments of all molecule systems have been achieved.

  11. GC-MS and FT-IR analysis of a coastal medicinal plant-Hyptis suaveolens (L.) Poit

    Institute of Scientific and Technical Information of China (English)

    Joselin Joseph; Solomon Jeeva

    2016-01-01

    Objective:To investigate the bioactive components of a coastal medicinal plant,Hyptis suaveolens (L.) Poit. (H. suaveolens) leaves using fourier transform-infrared spectroscopy and gas chromatography-mass spectrometer (GC-MS). Methods: The chemical compositions of the ethanol extract of whole plant ofH. suaveolens was investigated using PerkinElmerGC-MS, while the mass spectra of the compounds found in the extract was matched with the National Institute of Standard and Technology library. Results: The results of fourier transform-infrared spectroscopy analysis confirmed the presence of secondary alcohols, phenols, alkanes, alkynes, aromatics, nitro compounds and aliphatic compounds.GC-MS analysis of the ethanolic extract revealed the existence of 30 phytochemical compounds. 5,5-Dimethylimidazolidin-2,4-diamine (20.35%) was found to be the major compound. Conclusions: The results of this study offer a platform to useH. suaveolens leaves as herbal alternative for various diseases.

  12. GC-MS and FT-IR analysis of a coastal medicinal plant-Hyptis suaveolens (L. Poit

    Directory of Open Access Journals (Sweden)

    Joselin Joseph

    2016-05-01

    Full Text Available Objective: To investigate the bioactive components of a coastal medicinal plant, Hyptis suaveolens (L. Poit. (H. suaveolens leaves using fourier transform-infrared spectroscopy and gas chromatography-mass spectrometer (GC-MS. Methods: The chemical compositions of the ethanol extract of whole plant of H. suaveolens was investigated using PerkinElmer GC-MS, while the mass spectra of the compounds found in the extract was matched with the National Institute of Standard and Technology library. Results: The results of fourier transform-infrared spectroscopy analysis confirmed the presence of secondary alcohols, phenols, alkanes, alkynes, aromatics, nitro compounds and aliphatic compounds. GC-MS analysis of the ethanolic extract revealed the existence of 30 phytochemical compounds. 5,5-Dimethylimidazolidin-2,4-diamine (20.35% was found to be the major compound. Conclusions: The results of this study offer a platform to use H. suaveolens leaves as herbal alternative for various diseases.

  13. Physico-chemical and electrochemical characterization of Ti/RhO{sub x}-IrO{sub 2} electrodes using sol-gel technology

    Energy Technology Data Exchange (ETDEWEB)

    Klink, M.J.; Makgae, M.E. [Institute of Molecular Sciences, School of Chemistry, Faculty of Science, University of the Witwatersrand, Private Bag 3, Jorrissen Street, Johannesburg 2050 (South Africa); Crouch, A.M., E-mail: Andrew.Crouch@wits.ac.za [Institute of Molecular Sciences, School of Chemistry, Faculty of Science, University of the Witwatersrand, Private Bag 3, Jorrissen Street, Johannesburg 2050 (South Africa)

    2010-11-01

    Sol-gel technology has been successfully used for the incorporation of RhO{sub x}-IrO{sub 2} on a Ti substrate. RhO{sub x}-IrO{sub 2} was prepared from chloride precursors of Rh and Ir, for surface studies. These metal oxides were then immobilised on solid Ti substrates via dip withdrawal coating methods to form thin films. The Ti/RhO{sub x}-IrO{sub 2} thin films were extensively characterized in terms of surface characterization and chemical composition and used in the oxidation of phenol. Thermo-gravimetric analysis (TGA) determined the calcination temperature at 700 deg. C where no further structural changes occurred due to mass loss. The rhodium oxide showed two-phase formations, RhO{sub 2} and Rh{sub 2}O{sub 3}, which were attributed to high calcinated temperatures compare to one phase IrO{sub 2} which was stable at lower temperatures. The scanning electron microscopy (SEM) showed that the morphology of the film was found to be rough with a grain-like appearance in the 150-nm range. The phase composition of these metal oxides was determined by X-ray diffraction (XRD) technique and found to have crystalline structures. The results obtained from Rutherford backscattering spectrometry (RBS) revealed information regarding the chemical composition of the metal oxides and confirmed the diffusion of Rh and Ir into the Ti substrate. Electrochemical characterization of the Ti/RhO{sub x}-IrO{sub 2} electrode, via cyclic voltammetry (CV), showed distinctive redox peaks: anodic and cathodic peaks associated with the oxidation and reduction of the ferricyanide-ferrocyanide couple was seen at 250 and 100 mV respectively; the peak observed at 1000 mV was associated with oxygen evolution and a broad reductive wave at -600 mV can be ascribed to the Ti/RuO{sub x}-IrO{sub 2} reduction, which proved that the Ti/RhO{sub x}-IrO{sub 2} electrode were electroactive and exhibit fast electrochemistry.

  14. Dosimetric analysis of urethral strictures following HDR 192Ir brachytherapy as monotherapy for intermediate- and high-risk prostate cancer

    International Nuclear Information System (INIS)

    Díez, Patricia; Mullassery, Vinod; Dankulchai, Pittaya; Ostler, Peter; Hughes, Robert; Alonzi, Roberto; Lowe, Gerry; Hoskin, Peter J.

    2014-01-01

    Background and purpose: To evaluate dosimetric parameters related to urethral strictures following high dose-rate brachytherapy (HDRBT) alone for prostate cancer. Material and methods: Ten strictures were identified in 213 patients treated with HDRBT alone receiving 34 Gy in four fractions, 36 Gy in four fractions, 31.5 Gy in 3 fractions or 26 Gy in 2 fractions. A matched-pair analysis used 2 controls for each case matched for dose fractionation schedule, pre-treatment IPSS score, number of needles used and clinical target volume. The urethra was divided into membranous urethra and inferior, mid and superior thirds of the prostatic urethra. Results: Stricture rates were 3% in the 34 Gy group, 4% in the 36 Gy group, 6% in the 31.5 Gy group and 4% in the 26 Gy group. The median time to stricture formation was 26 months (range 8–40). The dosimetric parameters investigated were not statistically different between cases and controls. No correlation was seen between stricture rate and fractionation schedule. Conclusions: Urethral stricture is an infrequent complication of prostate HDRBT when used to deliver high doses as sole treatment, with an overall incidence in this cohort of 10/213 (4.7%). In a matched pair analysis no association with dose schedule or urethral dosimetry was identified, but the small number of events limits definitive conclusions

  15. Advantages of TOF-SIMS analysis of hydroxyapatite and fluorapatite in comparison with XRD, HR-TEM and FT-IR.

    Science.gov (United States)

    Okazaki, Masayuki; Hirata, Isao; Matsumoto, Takuya; Takahashi, Junzo

    2005-12-01

    The chemical analysis of hydroxyapatite and fluorapatite was carried out using time-of-flight secondary ion mass spectrometry (TOF-SIMS). Hydroxyapatite and fluorapatite were synthesized at 80 +/- 1 degrees C and pH 7.4 +/- 0.2. Fluorapatite was better crystallized, with its (300) reflection shifted to a slightly higher angle. High-resolution transmission electron microscopy clearly revealed a typical, regular hexagonal cross section perpendicular to the c-axis for fluorapatite and a flattened hexagonal cross section for hydroxyapatite. FT-IR spectra of fluorapatite confirmed the absence of OH absorption peak--which was seen in hydroxyapatite at about 3570 cm(-1). TOF-SIMS mass spectra showed a peak at 40 amu due to calcium. In addition, a peak at 19 amu due to fluorine could be clearly seen, although the intensities of PO, PO2, and PO3 were very low. It was confirmed that TOF-SIMS clearly showed the differences between positive and negative mass spectra of hydroxyapatite and fluorapatite, especially for F-. We concluded that TOF-SIMS exhibited distinct advantages compared with other methods of analysis.

  16. V{sub 1+x}Nb{sub 1-x}IrB{sub 2} (x ∼ 0.1), the first quaternary metal-rich -boride adopting the Mo{sub 2}IrB{sub 2}-type structure: Synthesis, crystal and electronic structure and bonding analysis

    Energy Technology Data Exchange (ETDEWEB)

    Goerens, Christian; Fokwa, Boniface P.T. [Institute of Inorganic Chemistry, RWTH Aachen University (Germany)

    2013-02-15

    Polycrystalline samples and single crystals of the new metal-rich boride V{sub 1+x}Nb{sub 1-x}IrB{sub 2} (x ∼ 0.1), were synthesized by arc-melting the elements in a water-cooled copper crucible under an argon atmosphere and characterized by X-ray diffraction and EDX measurements. The crystal structure was refined on the basis of single crystal data. The new phase adopts the Mo{sub 2}IrB{sub 2}-type structure (space group Pnnm, no. 58) with the lattice parameters a = 7.301(7) Aa, b = 9.388(9) Aa and c = 3.206(5) Aa. It is the first quaternary representative of Mo{sub 2}IrB{sub 2}-type structure. The structure contains zigzag B{sub 4}-fragments with boron-boron distances of 1.83-1.85 Aa. The electronic density of states and crystal orbital Hamilton population (for bonding analysis) were calculated, using the linear muffin-tin orbital atomic sphere approximation (LMTO-ASA) method. According to these calculations, this metal-rich compound should be metallic, as expected. Furthermore, very strong boron-boron interactions are observed in the zigzag B{sub 4}-fragment and two significantly different Ir-B interactions are observed in the new phase and the prototype Mo{sub 2}IrB{sub 2}. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Synthesis and XRD, FT-IR vibrational, UV-vis, and nonlinear optical exploration of novel tetra substituted imidazole derivatives: A synergistic experimental-computational analysis

    Science.gov (United States)

    Ahmad, Muhammad Saeed; Khalid, Muhammad; Shaheen, Muhammad Ashraf; Tahir, Muhammad Nawaz; Khan, Muhammad Usman; Braga, Ataualpa Albert Carmo; Shad, Hazoor Ahmad

    2018-04-01

    Heterocyclic compounds have potential applications in many fields of life. We synthesized novel tetra substituted imidazoles by four-component condensation of benzil, substituted aldehydes, substituted anilines and ammonium acetate as a source of ammonia and acetic acid as the solvent. Their chemical structures were resolved through X-ray crystallographic and spectroscopic (Fourier transform IR and UV-vis) techniques. In addition to experimental analysis, density functional theory (DFT) calculations at the B3LYP/6-311 + G(d,p) level were performed on 4-bromo-2-(1-(4-methoxyphenyl)-4,5-diphenyl-1H-imidazole-2-yl)phenol (1), 4-bromo-2-(1-(1-naphthalen-yl)-4,5-diphenyl-1H-imidazole-2-yl)phenol (2), and 2-(1-(2-chlorophenyl)-4,5-diphenyl-1-H-imidazole-2-yl)-6-methoxyphenol (3) to obtain the optimized geometry and spectroscopic (Fourier transform IR and UV-vis) and non-linear optical properties. Frontier molecular orbital analysis was performed at the Hartee-Fock/6-311+g(d,p) and DFT/B3LYP/6-311+G(d,p) levels of theory. Natural bond orbital (NBO) and UV-vis spectral analyses were performed at the M06-2X/6-31+G(d,p) and time-dependent DFT/B3LYP/6-311+G(d,p) levels, respectively. Overall, the DFT findings show good agreement with the experimental data. The hyper conjugative interaction network, which is responsible for the stability of compounds 1, 2 and 3 was explored by the NBO approach. The global reactivity parameters were explored with use of the energy of the frontier molecular orbitals. DFT calculations predict the first-order hyperpolarizabilities of compounds 1, 2 and 3 are 294.89 × 10-30, 219.45 × 10-30 and 146.77 × 10-30 esu, respectively. A two-state model was used to describe the non-linear optical properties of the compounds investigated.

  18. Comprehensive gene expression analysis of the NAC gene family under normal growth conditions, hormone treatment, and drought stress conditions in rice using near-isogenic lines (NILs) generated from crossing Aday Selection (drought tolerant) and IR64.

    Science.gov (United States)

    Nuruzzaman, Mohammed; Sharoni, Akhter Most; Satoh, Kouji; Moumeni, Ali; Venuprasad, Ramiah; Serraj, Rachid; Kumar, Arvind; Leung, Hei; Attia, Kotb; Kikuchi, Shoshi

    2012-05-01

    The NAC (NAM, ATAF1/2 and CUC2) genes are plant-specific transcriptional factors known to play diverse roles in various plant developmental processes. We describe the rice (Oryza sativa) OsNAC genes expression profiles (GEPs) under normal and water-deficit treatments (WDTs). The GEPs of the OsNAC genes were analyzed in 25 tissues covering the entire life cycle of Minghui 63. High expression levels of 17 genes were demonstrated in certain tissues under normal conditions suggesting that these genes may play important roles in specific organs. We determined that 16 genes were differentially expressed under at least 1 phytohormone (NAA, GA3, KT, SA, ABA, and JA) treatment. To investigate the GEPs in the root, leaf, and panicle of three rice genotypes [e.g., 2 near-isogenic lines (NILs) and IR64], we used two NILs from a common genetic combination backcross developed by Aday Selection and IR64. WDTs were applied using the fraction of transpirable soil water at severe, mild, and control conditions. Transcriptomic analysis using a 44K oligoarray from Agilent was performed on all the tissue samples. We identified common and specific genes in all tissues from the two NILs under both WDTs, and the majority of the OsNAC genes that were activated were in the drought-tolerant IR77298-14-1-2-B-10 line compared with the drought-susceptible IR77298-14-1-2-B-13 or IR64. In IR77298-14-1-2-B-10, seventeen genes were very specific in their expression levels. Approximately 70 % of the genes from subgroups SNAC and NAM/CUC3 were activated in the leaf, but 37 % genes from subgroup SND were inactivated in the root compared with the control under severe stress conditions. These results provide a useful reference for the cloning of candidate genes from the specific subgroup for further functional analysis.

  19. Vibrational frequency analysis, FT-IR, DFT and M06-2X studies on tert-Butyl N-(thiophen-2yl)carbamate

    Science.gov (United States)

    Sert, Yusuf; Singer, L. M.; Findlater, M.; Doğan, Hatice; Çırak, Ç.

    2014-07-01

    In this study, the experimental and theoretical vibrational frequencies of a newly synthesized tert-Butyl N-(thiophen-2yl)carbamate have been investigated. The experimental FT-IR (4000-400 cm-1) spectrum of the molecule in the solid phase have been recorded. The theoretical vibrational frequencies and optimized geometric parameters (bond lengths and bond angles) have been calculated by using density functional theory (DFT/B3LYP: Becke, 3-parameter, Lee-Yang-Parr) and DFT/M06-2X (the highly parametrized, empirical exchange correlation function) quantum chemical methods with the 6-311++G(d,p) basis set by Gaussian 09W software, for the first time. The vibrational frequencies have been assigned using potential energy distribution (PED) analysis by using VEDA 4 software. The computational optimized geometric parameters and vibrational frequencies have been found to be in good agreement with the corresponding experimental data, and with related literature results. In addition, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energies and the other related molecular energy values have been calculated and are depicted.

  20. Raman and Mid-IR Spectral Analysis of the Atacamite-Structure Hydroxyl/Deuteroxyl Nickel Chlorides Ni2(OH/D)3Cl

    Institute of Scientific and Technical Information of China (English)

    LIU Xiao-Dong; Hagihala Masato; ZHENG Xu-Guang; MENG Dong-Doug; GUO Qi-Xin

    2011-01-01

    @@ Vibrational spectra(Raman 4000-95cm-1 and mid-IR 4000-400cm-1) of the atacamite-structure Ni2(OH)3Cl,including a rarely reported kind of asymmetric trimetric hydrogen bond, as a member of the geometrically frustrated material series and its deuteride Ni2(OD)3Cl are, to the best of our knowledge, reported for the first time and analyzed at room temperature.Through a comparative study of four spectra according to their crystal structural parameters, we assign OH stretching modes v(OH) in a functional group region(3700-3400 cm-1) and their deformation modes δ(NiOH/D) in the correlation peak region(900-600 cm-1)with the corresponding mode frequency ratios ωv(OD)/ωv(OH)≈73% and ωδ(NiOD)/ωδ(NiOH)≈75%, and further self-consistently suggest NiO and Ni-Cl related modes in the fingerprint region(500-200cm-1 and 200-Ocm-1, respectively) by use of the unified six-ligand NiO5Cl and NiO4Cl2 frames.This report may contribute to the spectral analysis of other hydroxyl transition-metal halides and to the understanding of the fundamental physics of their exotic magnetic geometrical frustration property from the spectral changes around the corresponding low transition temperatures.

  1. Quantum mechanical, spectroscopic studies (FT-IR, FT-Raman, NMR, UV) and normal coordinates analysis on 3-([2-(diaminomethyleneamino) thiazol-4-yl] methylthio)-N'-sulfamoylpropanimidamide

    Science.gov (United States)

    Muthu, S.; Uma Maheswari, J.; Sundius, Tom

    2013-05-01

    Famotidine (3-([2-(diaminomethyleneamino) thiazol-4-yl] methylthio)-N'-sulfamoylpropanimidamide) is a histamine H2-receptor antagonist that inhibits stomach acid production, and it is commonly used in the treatment of peptic ulcer disease (PUD) and gastroesophageal reflux disease (GERD/GORD). Quantum chemical calculations of the equilibrium geometry of famotidine in the ground state were carried out using density functional theory (DFT/B3LYP) with the 6-311G(d,p) basis set. In addition, harmonic vibrational frequencies, infrared intensities and Raman activities were calculated at the same level of theory. A detailed interpretation of the infrared and Raman spectrum of the drug is also reported. Theoretical simulations of the FT-IR, and FT-Raman spectra of the title compound have been calculated. Good correlations between the experimental 1H and 13C NMR chemical shifts and calculated GIAO shielding tensors were found. The results of the energy and oscillator strength calculations by time-dependent density functional theory (TD-DFT) supplement the experimental findings. Total and partial density of state (TDOS and PDOS) and also overlap population density of state (COOP or OPDOS) diagrams analysis were presented. The dipole moment, linear polarizability and first order hyperpolarizability values were also computed. The linear polarizability and first order hyperpolarizabilities of the studied molecule indicate that the compound is a good candidate for nonlinear optical materials.

  2. Sedimentation technique of waste bituminization and thermogravimetric characteristics of the final products

    Energy Technology Data Exchange (ETDEWEB)

    Zeger, J; Knotik, K; Jakusch, H

    1976-01-01

    In the research centre of the Oesterreichische Studiengesellschaft fuer Atomenergie GesmbH a semitechnical plant has been installed for waste bituminization, which has been tested inactively since 1973. This plant is using a new technological process for embedding. One of the important features of this new process is that the, normally inactive solution water is distilled off prior to the embedding, resulting in dry and powdery salts. The second important feature is that the mixing of these dry salts with the thin fluid bitumen is done by sedimentation. Expecially there is no mechanical aid used for mixing. Thermogravimetric analysis of samples which simulated the final products of this pilot plant, were carried out to verify the best working parameters and to study the possible chemical damage to the bitumen. Analysis was performed by heating the samples, consisting of various mixtures of bitumen and inorganic salts, in a METTLER-Thermoanalyzer up to 500/sup 0/C using different atmospheres (air, nitrogen). It could be shown that only nitrate and nitrite especially in combination with Fe(III)-ions are of negative influence on the thermostability of bitumen. They lead to a sudden and quick weight loss of the samples between 370 and 410/sup 0/C (above the melting point of both NaNO/sub 2/ and NaNO/sub 3/). The Fe-ions hava a catalytic influence, as it could be shown that 1 1% addiation of Fe(NO/sub 3/)/sub 3/ to NaNO/sub 3/ leads to a considerable acceleration of the incineration. This influence of the Fe(III)-ion can be suppressed to some extend by a hydrolysis prior to the embedding. In preparation of further studies concerning the behaviour of radiation damaged bitumen there has been developed a method of measuring the dose rate of an unknown radioactive salt mixture at any point of this mixture. This is done by making two measurements with glass dosimeters. One with a beta-absorber to get a pure gamma-dose and the other without it to get the combined beta and

  3. Sedimentation technique of waste bituminization and thermogravimetric characteristics of the finalproducts

    International Nuclear Information System (INIS)

    Zeger, J.; Knotik, K.

    1976-01-01

    In the research centre of the Oesterreichische Studiengesellschaft fuer Atomenergie GesmbH a semitechnical plant has been installed for waste bituminization, which has been tested inactively since 1973. This plant is using a new technological process for embedding. One of the important features of this new process is that the, normally inactive solution water is distilled off prior to the embedding, resulting in dry and powdery salts. The second important feature is that the mixing of these dry salts with the thin fluid bitumen is done by sedimentation. Expecially there is no mechanical aid used for mixing. Thermogravimetric analysis of samples which simulated the final products of this pilot plant, were carried out to verify the best working parameters and to study the possible chemical damage to the bitumen. Analysis was performed by heating the samples, consisting of various mixtures of bitumen and inorganic salts, in a METTLER-Thermoanalyzer up to 500 0 C using different atmospheres (air, nitrogen). It could be shown that only nitrate and nitrite especially in combination with Fe(III)-ions are of negative influence on the thermostability of bitumen. They lead to a sudden and quick weight loss of the samples between 370 and 410 0 C (above the melting point of both NaNO 2 and NaNO 3 ). The Fe-ions hava a catalytic influence, as it could be shown that 1 1% addiation of Fe(NO 3 ) 3 to NaNO 3 leads to a considerable acceleration of the incineration. This influence of the Fe(III)-ion can be suppressed to some extend by a hydrolysis prior to the embedding. In preparation of further studies concerning the behaviour of radiation damaged bitumen there has been developed a method of measuring the dose rate of an unknown radioactive salt mixture at any point of this mixture. This is done by making two measurements with glass dosimeters. One with a beta-absorber to get a pure gamma-dose and the other without it to get the combined beta and gamma dose. (author)

  4. Characterization of prepared In2O3 thin films: The FT-IR, FT-Raman, UV-Visible investigation and optical analysis.

    Science.gov (United States)

    Panneerdoss, I Joseph; Jeyakumar, S Johnson; Ramalingam, S; Jothibas, M

    2015-08-05

    In this original work, the Indium oxide (In2O3) thin film is deposited cleanly on microscope glass substrate at different temperatures by spray pyrolysis technique. The physical properties of the films are characterized by XRD, SEM, AFM and AFM measurements. The spectroscopic investigation has been carried out on the results of FT-IR, FT-Raman and UV-Visible. XRD analysis exposed that the structural transformation of films from stoichiometric to non-stoichiometric orientation of the plane vice versa and also found that, the film is polycrystalline in nature having cubic crystal structure with a preferred grain orientation along (222) plane. SEM and AFM studies revealed that, the film with 0.1M at 500°C has spherical grains with uniform dimension. The complete vibrational analysis has been carried out and the optimized parameters are calculated using HF and DFT (CAM-B3LYP, B3LYP and B3PW91) methods with 3-21G(d,p) basis set. Furthermore, NMR chemical shifts are calculated by using the gauge independent atomic orbital (GIAO) technique. The molecular electronic properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, molecular electrostatic potential energy (MEP) analysis and Polarizability first order hyperpolarizability calculations are performed by time dependent DFT (TD-DFT) approach. The energy excitation on electronic structure is investigated and the assignment of the absorption bands in the electronic spectra of steady compound is discussed. The calculated HOMO and LUMO energies showed the enhancement of energy gap by the addition of substitutions with the base molecule. The thermodynamic properties (heat capacity, entropy, and enthalpy) at different temperatures are calculated and interpreted in gas phase. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

  5. FT-IR, FT-Raman, NMR studies and ab initio-HF, DFT-B3LYP vibrational analysis of 4-chloro-2-fluoroaniline.

    Science.gov (United States)

    Arivazhagan, M; Anitha Rexalin, D

    2012-10-01

    The Fourier transform infrared (FT-IR) and Fourier transform Raman (FT-Raman) spectra of 4-chloro-2-fluoroaniline (CFA) have been recorded and analyzed. The equilibrium geometry, bonding features and harmonic vibrational frequencies have been investigated with the help of ab initio and density functional theory (DFT) methods. The assignments of the vibrational spectra have been carried out with the help of normal coordinate analysis (NCA) following the scaled quantum mechanical force field methodology. The (1)H and (13)C nuclear magnetic resonance (NMR) chemical shifts of the molecule are calculated by the Gauge including atomic orbital (GIAO) method. The first order hyperpolarizability (β(0)) of this novel molecular system and related properties (β, α(0) and Δα) of CFA are calculated using B3LYP/6-311++G(d,p) and HF/6-311++G(d,p) methods on the finite-field approach. The calculated results also show that the CFA molecule might have microscopic nonlinear optical (NLO) behavior with non-zero values. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The result confirms the occurrence of intramolecular charge transfer (ICT) within the molecule. The HOMO-LUMO energies UV-vis spectral analysis and MEP are performed by B3LYP/6-311++G(d,p) approach. A detailed interpretation of the infrared and Raman spectra of CFA is also reported based on total energy distribution (TED). The difference between the observed and scaled wave number values of the most of the fundamentals is very small. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Thermogravimetric study of superconducting YBa2Cu3O9-x in hydrogen

    International Nuclear Information System (INIS)

    Swaminathan, K.; Janaki, J.; Rao, G.V.N.; Sreedharan, O.M.; Radhakrishnan, T.S.

    1988-01-01

    The thermogravimetric curve of YBa 2 Cu 3 O 9-x in hydrogen exhibits five steps, the first two corresponding to the reduction of copper oxide to copper by about 683 K (as identified by XRD on quenched samples) followed by three more steps predominantly due to hydration-dehydration behaviour of BaO. The need for blank corrections and the choice of 1223 K as the temperature for the determination of oxygen stoichiometry are discussed. 6 refs.; 2 figs.; 1 table

  7. Synthesis, characterization and thermogravimetric study of zinc and cadmium acetates-polyaniline hybrids

    International Nuclear Information System (INIS)

    Fernandes de Farias, Robson

    2004-01-01

    By dissolution of respective acetates and conducting polymer in dimethylformamide, homogeneous zinc acetate and cadmium acetate-polyaniline (PANI) hybrids were synthesized and characterized by infrared spectroscopy, thermogravimetry and SEM microscopy. The infrared spectra suggests that there are interactions between PANI and the metal cations involving both, imine and amine nitrogens in a typical Lewis acid-base reaction. The thermogravimetric degradation profile of the synthesized hybrids resembles those exhibited by PANI samples

  8. Modified thermogravimetric apparatus to measure magnetic susceptibility on-line during annealing of metastable ferromagnetic materials

    International Nuclear Information System (INIS)

    Luciani, G.; Constantini, A.; Branda, F.; Ausanio, G.; Hison, C.; Iannotti, V.; Luponio, C.; Lanotte, L.

    2004-01-01

    The insertion of proper coils to generate a magnetic field, with controlled gradient, in a standard thermogravimetric apparatus is shown to be a valid solution to measure on-line, upon heat treatment, the magnetic susceptibility in ribbon shaped samples of a metastable ferromagnetic material. The method is very useful to individuate the annealing conditions that optimise soft or hard magnetic properties without using separate apparatuses for heat treatment, control of the structural phase transition and characterization of magnetic susceptibility

  9. Synthesis and physicochemical analysis of Sm (II, III) acetylacetone chelate complexes

    International Nuclear Information System (INIS)

    Kostyuk, N.N.; Dik, T.A.; Trebnikov, A.G.

    2004-01-01

    Sm (II, III) acetylacetone chelate complexes were synthesized by electrochemical method. It was shown that anode dissolution of the metal samarium over acetylacetone leads to formation of the Sm (II, III) chelate complexes: xSm(acac)2 · ySm(acac)3 · zH(acac). Factors x, y and z depend on quantity of the electricity, which flew through the electrolysis cell. The compositions of the obtained substances were confirmed by the physicochemical analysis (ultimate analysis, IR-, mass spectroscopy and thermal analysis (thermogravimetric, isothermal warming-up and differential scanning colorimetry). (Authors)

  10. Sedimentation technique of waste bituminization and thermogravimetric characteristics of the final products

    International Nuclear Information System (INIS)

    Zeger, J.; Knotik, K.; Jakusch, H.

    1976-01-01

    In the research centre of the Oesterreichische Studiengesellschaft fuer Atomenergie GmbH a semi-technical plant has been installed for waste bituminization, which has been tested inactively since 1973. This plant uses a new technological process for embedding. One of the important features of this new process is that the solution water, which is normally inactive, is distilled off before embedding, resulting in dry and powdery salts. The second important feature is that these dry salts are mixed with the thin fluid bitumen by sedimentation. A special feature is that there is no mechanical aid used for mixing. Thermogravimetric analysis of samples which simulated the final products of this pilot plant was carried out to verify the best working parameters and to study the possible chemical damage to the bitumen. It was shown that only nitrate and nitrite, especially in combination with Fe(III)-ions, are of negative influence on the thermostability of bitumen. They lead to a sudden and quick weight loss of the samples between 370 and 410 0 C (above the melting point of both NaNO 2 and NaNO 3 ). The Fe-ions have a catalytic influence, as it could be shown that a 1% addition of Fe(NO 3 ) 3 to NaNO 3 leads to a considerable acceleration of the incineration. This influence of the Fe(III)-ion can be suppressed to some extent by a hydrolysis before the embedding. There is, however, no danger to the embedding process from these effects since the process temperature of maximum 200 0 C is well below the ignition temperatures. A method of measuring the dose rate of an unknown radioactive salt mixture at any point of this mixture has been developed. This is done by making two measurements with glass dose-meters, one with a beta-absorber to get a pure gamma dose and the other without it to get the combined beta and gamma dose. During the first measurement the dose-meters were protected against contamination by a thin layer of rubber

  11. Efficient Synthesis of Ir-Polyoxometalate Cluster Using a Continuous Flow Apparatus and STM Investigation of Its Coassembly Behavior on HOPG Surface.

    Science.gov (United States)

    Zhang, Junyong; Chang, Shaoqing; Suryanto, Bryan H R; Gong, Chunhua; Zeng, Xianghua; Zhao, Chuan; Zeng, Qingdao; Xie, Jingli

    2016-06-06

    Taking advantage of a continuous-flow apparatus, the iridium(III)-containing polytungstate cluster K12Na2H2[Ir2Cl8P2W20O72]·37H2O (1) was obtained in a reasonable yield (13% based on IrCl3·H2O). Compound 1 was characterized by Fourier transform IR, UV-visible, (31)P NMR, electrospray ionization mass spectrometry (ESI-MS), and thermogravimetric analysis measurements. (31)P NMR, ESI-MS, and elemental analysis all indicated 1 was a new polytungstate cluster compared with the reported K14[(IrCl4)KP2W20O72] compound. Intriguingly, the successful isolation of 1 relied on the custom-built flow apparatus, demonstrating the uniqueness of continuous-flow chemistry to achieve crystalline materials. The catalytic properties of 1 were assessed by investigating the activity on catalyzing the electro-oxidation of ruthenium tris-2,2'-bipyridine [Ru(bpy)3](2+/3+). The voltammetric behavior suggested a coupled catalytic behavior between [Ru(bpy)3](3+/2+) and 1. Furthermore, on the highly oriented pyrolytic graphite surface, 1,3,5-tris(10-carboxydecyloxy) benzene (TCDB) was used as the two-dimensional host network to coassemble cluster 1; the surface morphology was observed by scanning tunneling microscope technique. "S"-shape of 1 was observed, indicating that the cluster could be accommodated in the cavity formed by two TCDB host molecules, leading to a TCDB/cluster binary structure.

  12. Molecular structure, electronic properties, NLO, NBO analysis and spectroscopic characterization of Gabapentin with experimental (FT-IR and FT-Raman) techniques and quantum chemical calculations

    Science.gov (United States)

    Sinha, Leena; Karabacak, Mehmet; Narayan, V.; Cinar, Mehmet; Prasad, Onkar

    2013-05-01

    Gabapentin (GP), structurally related to the neurotransmitter GABA (gamma-aminobutyric acid), mimics the activity of GABA and is also widely used in neurology for the treatment of peripheral neuropathic pain. It exists in zwitterionic form in solid state. The present communication deals with the quantum chemical calculations of energies, geometrical structure and vibrational wavenumbers of GP using density functional (DFT/B3LYP) method with 6-311++G(d,p) basis set. In view of the fact that amino acids exist as zwitterions as well as in the neutral form depending on the environment (solvent, pH, etc.), molecular properties of both the zwitterionic and neutral form of GP have been analyzed. The fundamental vibrational wavenumbers as well as their intensities were calculated and compared with experimental FT-IR and FT-Raman spectra. The fundamental assignments were done on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanical (SQM) method. The electric dipole moment, polarizability and the first hyperpolarizability values of the GP have been calculated at the same level of theory and basis set. The nonlinear optical (NLO) behavior of zwitterionic and neutral form has been compared. Stability of the molecule arising from hyper-conjugative interactions and charge delocalization has been analyzed using natural bond orbital analysis. Ultraviolet-visible (UV-Vis) spectrum of the title molecule has also been calculated using TD-DFT method. The thermodynamic properties of both the zwitterionic and neutral form of GP at different temperatures have been calculated.

  13. Comprehensive GC–FID, GC–MS and FT-IR spectroscopic analysis of the volatile aroma constituents of Artemisia indica and Artemisia vestita essential oils

    Directory of Open Access Journals (Sweden)

    Manzoor A. Rather

    2017-05-01

    Full Text Available In the current study, the leaf volatile constituents of the essential oils of Artemisia indica Willd. and Artemisia vestita Wall were studied using a combination of capillary GC–FID, GC–MS and FT-IR (Fourier-Transform Infra-Red analytical techniques. The analysis led to the identification of 42 compounds in the essential oil of A. indica, representing 96.6% of the essential oil and the major components were found to be artemisia ketone (42.1%, germacrene D (8.6%, borneol (6.1% and cis-chrysanthenyl acetate (4.8%. The essential oil was dominated by the presence of oxygenated monoterpenes constituting 65.2% of the total oil composition followed by sesquiterpene hydrocarbons and monoterpene hydrocarbons constituting 15.7% and 10.7%, respectively of the total oil composition. The essential oil composition of A. vestita was found to contain a total of 18 components representing 94.2% of the total oil composition. The principal components were found to be 1,8-cineole (46.8%, (E-citral (13.7%, limonene (9.8%, α-phellandrene (6.4%, camphor (5.0%, (Z and (E-thujones (3.0% each. Oxygenated monoterpenes were the dominant group of terpenes in the essential oil constituting 73.1% of the total oil composition followed by monoterpene hydrocarbons (17.3%. The results of the current study reveal remarkable differences in the essential oil compositions of these two Artemisia species already reported in the literature from other parts of the globe.

  14. Spin orientations of the spin-half Ir(4+) ions in Sr3NiIrO6, Sr2IrO4, and Na2IrO3: Density functional, perturbation theory, and Madelung potential analyses.

    Science.gov (United States)

    Gordon, Elijah E; Xiang, Hongjun; Köhler, Jürgen; Whangbo, Myung-Hwan

    2016-03-21

    The spins of the low-spin Ir(4+) (S = 1/2, d(5)) ions at the octahedral sites of the oxides Sr3NiIrO6, Sr2IrO4, and Na2IrO3 exhibit preferred orientations with respect to their IrO6 octahedra. We evaluated the magnetic anisotropies of these S = 1/2 ions on the basis of density functional theory (DFT) calculations including spin-orbit coupling (SOC), and probed their origin by performing perturbation theory analyses with SOC as perturbation within the LS coupling scheme. The observed spin orientations of Sr3NiIrO6 and Sr2IrO4 are correctly predicted by DFT calculations, and are accounted for by the perturbation theory analysis. As for the spin orientation of Na2IrO3, both experimental studies and DFT calculations have not been unequivocal. Our analysis reveals that the Ir(4+) spin orientation of Na2IrO3 should have nonzero components along the c- and a-axis directions. The spin orientations determined by DFT calculations are sensitive to the accuracy of the crystal structures employed, which is explained by perturbation theory analyses when interactions between adjacent Ir(4+) ions are taken into consideration. There are indications implying that the 5d electrons of Na2IrO3 are less strongly localized compared with those of Sr3NiIrO6 and Sr2IrO4. This implication was confirmed by showing that the Madelung potentials of the Ir(4+) ions are less negative in Na2IrO3 than in Sr3NiIrO6 and Sr2IrO4. Most transition-metal S = 1/2 ions do have magnetic anisotropies because the SOC induces interactions among their crystal-field split d-states, and the associated mixing of the states modifies only the orbital parts of the states. This finding cannot be mimicked by a spin Hamiltonian because this model Hamiltonian lacks the orbital degree of freedom, thereby leading to the spin-half syndrome. The spin-orbital entanglement for the 5d spin-half ions Ir(4+) is not as strong as has been assumed.

  15. IR and the Earth

    DEFF Research Database (Denmark)

    Corry, Olaf; Stevenson, Hayley

    2017-01-01

    , in the end, one finite interconnected space. Together these two starting points make for the basic conundrum of Inter- national Relations and the Earth: how does a divided world live on a single globe? This introduction first provides an overview of the recent rise of ‘the environment’ in international......, ‘what has the environment ever done for IR?’, before the plan for the rest of the book sketches the content and direction of the ensuing chapters that explore the problematique of International Relations and the Earth....

  16. Identification of Serine Conformers by Matrix-Isolation IR Spectroscopy Aided by Near-Infrared Laser-Induced Conformational Change, 2D Correlation Analysis, and Quantum Mechanical Anharmonic Computations.

    Science.gov (United States)

    Najbauer, Eszter E; Bazsó, Gábor; Apóstolo, Rui; Fausto, Rui; Biczysko, Malgorzata; Barone, Vincenzo; Tarczay, György

    2015-08-20

    The conformers of α-serine were investigated by matrix-isolation IR spectroscopy combined with NIR laser irradiation. This method, aided by 2D correlation analysis, enabled unambiguously grouping the spectral lines to individual conformers. On the basis of comparison of at least nine experimentally observed vibrational transitions of each conformer with empirically scaled (SQM) and anharmonic (GVPT2) computed IR spectra, six conformers were identified. In addition, the presence of at least one more conformer in Ar matrix was proved, and a short-lived conformer with a half-life of (3.7 ± 0.5) × 10(3) s in N2 matrix was generated by NIR irradiation. The analysis of the NIR laser-induced conversions revealed that the excitation of the stretching overtone of both the side chain and the carboxylic OH groups can effectively promote conformational changes, but remarkably different paths were observed for the two kinds of excitations.

  17. Detailed IR aperture measurements

    CERN Document Server

    Bruce, Roderik; Garcia Morales, Hector; Giovannozzi, Massimo; Hermes, Pascal Dominik; Mirarchi, Daniele; Quaranta, Elena; Redaelli, Stefano; Rossi, Carlo; Skowronski, Piotr Krzysztof; Wretborn, Sven Joel; CERN. Geneva. ATS Department

    2016-01-01

    MD 1673 was carried out on October 5 2016, in order to investigate in more detail the available aperture in the LHC high-luminosity insertions at 6.5 TeV and β∗=40 cm. Previous aperture measurements in 2016 during commissioning had shown that the available aperture is at the edge of protection, and that the aperture bottleneck at β∗=40 cm in certain cases is found in the separation plane instead of in the crossing plane. Furthermore, the bottlenecks were consistently found in close to the upstream end of Q3 on the side of the incoming beam, and not in Q2 on the outgoing beam as expected from calculations. Therefore, this MD aimed at measuring IR1 and IR5 separately (at 6.5 TeV and β∗=40 cm, for 185 µrad half crossing angle), to further localize the bottlenecks longitudinally using newly installed BLMs, investigate the difference in aperture between Q2 and Q3, and to see if any aperture can be gained using special orbit bumps.

  18. A novel FT-IR spectroscopic method based on lipid characteristics for qualitative and quantitative analysis of animal-derived feedstuff adulterated with ruminant ingredients.

    Science.gov (United States)

    Gao, Fei; Zhou, Simiao; Han, Lujia; Yang, Zengling; Liu, Xian

    2017-12-15

    The objective of this study was to explore the ability of Fourier transform infrared (FT-IR) spectroscopy to authenticate adulterated animal-derived feedstuff. A total of 18 raw meat and bone meals (MBMs), including 9 non-ruminant MBMs and 9 ruminant MBMs, were mixed to obtain 81 binary mixtures with specific proportions (1-35%). Lipid spectral characteristics were analyzed by FT-IR spectroscopy combined with chemometrics. Changes in FT-IR spectra were observed as adulterant concentration was varied. The results illustrate ruminant adulteration can be successfully distinguished based on lipid characteristics. PLS model was established to quantify ruminant adulteration, which was shown to be valid (R 2 P >0.90). Furthermore, the ratios of CC/CO and CC/CH(CH 2 ), as well as the number of CH(CH 2 ) in the fatty acids of adulterated lipids, were calculated, which showed that differences in the trans fatty acid content and the degree of unsaturation were the main contributors to determination of adulteration based on FT-IR spectroscopy. Copyright © 2017. Published by Elsevier Ltd.

  19. Reaction of LiD with water vapor: thermogravimetric and scanning electron microscopy studies

    International Nuclear Information System (INIS)

    Balooch, M; Dinh, L N; LeMay, J D

    2000-01-01

    The kinetics of hydroxide film growth on LiD have been studied by the thermogravimetric method in nitrogen saturated with water vapor and by scanning electron microscopy (SEM) of samples that have been exposed to air with 50% relative humidity. The reaction probability is estimated to be 4 x 10 -7 for LiD exposed to ambient air with 50% relative humidity, suggesting that the diffusion through the hydroxide film is not the limiting step on the overall process at high moisture levels. The rate of growth is drastically reduced when the temperature is increased to 60 C

  20. Thermogravimetric analytical procedures for characterizing New Zealand and eastern Australian coals

    Energy Technology Data Exchange (ETDEWEB)

    Benfell, K.E.; Beamish, B.B.; Rodgers, K.A. [University of Auckland, Auckland (New Zealand). Dept. of Geology

    1996-09-01

    Under tightly constrained experimental conditions (particle size {lt}75 {mu}m, sample mass 5.0 {+-} 0.5 mg), heating rate 15{degree}C min{sup -1}, dry air purge 50 mL min{sup -1}, maximum temperature 900{degree}C a repeatability of {lt} {+-} 2{degree}C, may be achieved for significant temperatures that characterize the differential thermogravimetric burning profiles of typical medium-volatile, bituminous Australian Gondwanan coals and high-volatile, bituminous New Zealand Cretaceous-Tertiary coals.

  1. Room temperature mid-IR single photon spectral imaging

    DEFF Research Database (Denmark)

    Dam, Jeppe Seidelin; Tidemand-Lichtenberg, Peter; Pedersen, Christian

    2012-01-01

    Spectral imaging and detection of mid-infrared (mid-IR) wavelengths are emerging as an enabling technology of great technical and scientific interest; primarily because important chemical compounds display unique and strong mid-IR spectral fingerprints revealing valuable chemical information. Whi...... 20 % for polarized incoherent light at 3 \\mum. The proposed method is relevant for existing and new mid-IR applications like gas analysis and medical diagnostics....

  2. New Ir Bis-Carbonyl Precursor for Water Oxidation Catalysis

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Daria L. [Department of Chemistry, Yale University, 225; Beltrán-Suito, Rodrigo [Department of Chemistry, Yale University, 225; Thomsen, Julianne M. [Department of Chemistry, Yale University, 225; Hashmi, Sara M. [Department of Chemical and Environmental; Materna, Kelly L. [Department of Chemistry, Yale University, 225; Sheehan, Stafford W. [Catalytic Innovations LLC, 70 Crandall; Mercado, Brandon Q. [Department of Chemistry, Yale University, 225; Brudvig, Gary W. [Department of Chemistry, Yale University, 225; Crabtree, Robert H. [Department of Chemistry, Yale University, 225

    2016-02-05

    This paper introduces IrI(CO)2(pyalc) (pyalc = (2-pyridyl)-2-propanoate) as an atom-efficient precursor for Ir-based homogeneous oxidation catalysis. This compound was chosen to simplify analysis of the water oxidation catalyst species formed by the previously reported Cp*IrIII(pyalc)OH water oxidation precatalyst. Here, we present a comparative study on the chemical and catalytic properties of these two precursors. Previous studies show that oxidative activation of Cp*Ir-based precursors with NaIO4 results in formation of a blue IrIV species. This activation is concomitant with the loss of the placeholder Cp* ligand which oxidatively degrades to form acetic acid, iodate, and other obligatory byproducts. The activation process requires substantial amounts of primary oxidant, and the degradation products complicate analysis of the resulting IrIV species. The species formed from oxidation of the Ir(CO)2(pyalc) precursor, on the other hand, lacks these degradation products (the CO ligands are easily lost upon oxidation) which allows for more detailed examination of the resulting Ir(pyalc) active species both catalytically and spectroscopically, although complete structural analysis is still elusive. Once Ir(CO)2(pyalc) is activated, the system requires acetic acid or acetate to prevent the formation of nanoparticles. Investigation of the activated bis-carbonyl complex also suggests several Ir(pyalc) isomers may exist in solution. By 1H NMR, activated Ir(CO)2(pyalc) has fewer isomers than activated Cp*Ir complexes, allowing for advanced characterization. Future research in this direction is expected to contribute to a better structural understanding of the active species. A diol crystallization agent was needed for the structure determination of 3.

  3. Use of a fluidized bed combustor and thermogravimetric analyzer for the study of coal ignition temperature

    International Nuclear Information System (INIS)

    Ávila, Ivonete; Crnkovic, Paula M.; Luna, Carlos M.R.; Milioli, Fernando E.

    2017-01-01

    Highlights: • Coal ignition tests were conducted in a fluidized bed and thermogravimetric conditions. • The use of two different ignition criteria showed a similar coal ignition temperature. • Coal ignition temperature was obtained by the changes of gas concentrations in FBC. • Ignition temperatures were associated with the activation energy of coal combustion. - Abstract: Ignition experiments with two bituminous coals were carried out in an atmospheric bubbling fluidized bed combustor (FBC) and a thermogravimetric analyzer (TGA). In the FBC tests, the rapid increase in O_2, CO_2, and SO_2 concentrations is an indication of the coal ignition. In the TGA technique, the ignition temperature was determined by the evaluation of the TGA curves in both combustion and pyrolysis processes. Model-Free Kinetics was applied and the coal ignition temperatures were associated with changes in the activation energy values during the combustion process. The results show the coal with the lowest activation energy also showed the lowest ignition temperature, highest values of volatile content and a higher heating value. The application of two different ignition criteria (TGA and FBC) resulted in similar ignition temperatures. The FBC curves indicated the high volatile coal ignites in the freeboard, i.e. during the feeding in the reactor, whereas the low volatile coal ignites in the bed. Finally, the physicochemical characteristics of the investigated coal types were correlated with their reactivities for the prediction of the ignition temperatures behaviors under different operating conditions as those in FBC.

  4. Thermogravimetric studies on electron beam initiated grafting of triallyl cyanurate onto polyethylene

    International Nuclear Information System (INIS)

    Chaki, T.K.; Bhowmik, A.K.; Mukunda, P.G.; Majali, A.B.; Tikku, V.K.

    1993-01-01

    Low density polyethylene (LDPE) containing different levels of triallyl cyanurate (TAC) have been prepared in a Brabender Plasticorder at 120 degC. The moulded samples in the form of rectangular compression sheet were irradiated under electron beam accelerator with different irradiation doses. Thermogravimetric and derivative thermogravimetric analyses of the irradiated samples grafted with TAC have been carried out in order to explore the decomposition behaviour and kinetics of decomposition under nitrogen atmosphere. Initial decomposition temperature (Ti), temperature at which 50% weight loss takes place (T50), final decomposition temperature (Tf) and the kinetic parameters evaluated from TGA traces of samples at different radiation doses (constant TAC level) and at different levels of TAC (constant radiation dose) have been reported. The effect of radiation dose and TAC level on the grafting of TAC onto polyethylene have been explained on the basis of degradation characteristics of irradiated samples. Kinetic studies show that the degradation of the irradiated samples follow first order reaction kinetics. Activation energies of degradation have been determined using McCarty and Green's method. Activation energy of the irradiated samples increases with the increasing radiation dose and also with increasing level of TAC. (author). 3 tabs

  5. The IRS-1 signaling system.

    Science.gov (United States)

    Myers, M G; Sun, X J; White, M F

    1994-07-01

    Insulin-receptor substrate 1 (IRS-1) is a principal substrate of the receptor tyrosine kinase for insulin and insulin-like growth factor 1, and a substrate for a tyrosine kinase activated by interleukin 4. IRS-1 undergoes multisite tyrosine phosphorylation and mediates downstream signals by 'docking' various proteins that contain Src homology 2 domains. IRS-1 appears to be a unique molecule; however, 4PS, a protein found mainly in hemopoietic cells, may represent another member of this family.

  6. Analysis of Fe species in zeolites by UV-VIS-NIR, IR spectra and voltammetry. Effect of preparation, Fe loading and zeolite type

    Czech Academy of Sciences Publication Activity Database

    Čapek, Libor; Kreibich, Viktor; Dědeček, Jiří; Grygar, Tomáš; Wichterlová, Blanka; Sobalík, Zdeněk; Martens, J. A.; Brosius, R.; Tokarová, V.

    2005-01-01

    Roč. 80, 1-3 (2005), s. 279-289 ISSN 1387-1811 R&D Projects: GA MŠk OC D15.20 Grant - others:European Union(XE) G5RD-CT-2001-00595 Institutional research plan: CEZ:AV0Z40400503 Keywords : Fe-zeolites * UV-VIS spectra * IR spectra * voltammetry * Fe complexes Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.355, year: 2005

  7. Analysis of clay smoking pipes from archeological sites in the region of the Guanabara Bay (Rio de Janeiro, Brazil) by FT-IR

    Science.gov (United States)

    Freitas, Renato P.; Ribeiro, Iohanna M.; Calza, Cristiane; Oliveira, Ana L.; Silva, Mariane L.; Felix, Valter S.; Ferreira, Douglas S.; Coelho, Felipe A.; Gaspar, Maria D.; Pimenta, André R.; Medeiros, Elanio A.; Lopes, Ricardo T.

    2016-06-01

    In this study, twenty samples of clay smoking pipes excavated in an 18 km2 area between the Macacu and Caceribu rivers, in the municipality of Itaboraí, Rio de Janeiro, Brazil were analyzed by FT-IR technique. The samples, excavated in different archeological sites of the region, are dated between the seventeenth and the nineteenth centuries and are part of the material culture left by Africans and African descendants that lived in the complex. FT-IR analyses and complementary SEM-EDS studies showed that the clay paste used in the manufacture of smoking pipes, mostly handcrafted, is composed of quartz, feldspar, phyllosilicates and iron oxides. Multivariate statistical tests (PCA) were applied to FT-IR data to assess the interactions between the archeological sites. The results indicated that one archeological site - Macacu IV - is greatly related to the other sites. The results obtained have helped archeologists and anthropologists in better understanding the manufacturing process employed in ancient ceramic artifacts produced during the period of colonial Brazil.

  8. Complementary online aerosol mass spectrometry and offline FT-IR spectroscopy measurements: Prospects and challenges for the analysis of anthropogenic aerosol particle emissions

    Science.gov (United States)

    Faber, Peter; Drewnick, Frank; Bierl, Reinhard; Borrmann, Stephan

    2017-10-01

    The aerosol mass spectrometer (AMS) is well established in investigating highly time-resolved dynamics of submicron aerosol chemical composition including organic aerosol (OA). However, interpretation of mass spectra on molecular level is limited due to strong fragmentation of organic substances and potential reactions inside the AMS ion chamber. Results from complementary filter-based FT-IR absorption measurements were used to explain features in high-resolution AMS mass spectra of different types of OA (e.g. cooking OA, cigarette smoking OA, wood burning OA). Using this approach some AMS fragment ions were validated in this study as appropriate and rather specific markers for a certain class of organic compounds for all particle types under investigation. These markers can therefore be used to get deeper insights in the chemical composition of OA based on AMS mass spectra in upcoming studies. However, the specificity of other fragment ions such as C2H4O2+ (m/z 60.02114) remains ambiguous. In such cases, complementary FT-IR measurements allow the interpretation of highly time-resolved AMS mass spectra at the level of molecular functional groups. Furthermore, this study discusses the challenges in reducing inorganic interferences (e.g. from water and ammonium salts) in FT-IR spectra of atmospheric aerosols to decrease spectral uncertainties for better comparisons and, thus, to get more robust results.

  9. Fourier Transform Infrared (FT-IR) and Laser Ablation Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) Imaging of Cerebral Ischemia: Combined Analysis of Rat Brain Thin Cuts Toward Improved Tissue Classification.

    Science.gov (United States)

    Balbekova, Anna; Lohninger, Hans; van Tilborg, Geralda A F; Dijkhuizen, Rick M; Bonta, Maximilian; Limbeck, Andreas; Lendl, Bernhard; Al-Saad, Khalid A; Ali, Mohamed; Celikic, Minja; Ofner, Johannes

    2018-02-01

    Microspectroscopic techniques are widely used to complement histological studies. Due to recent developments in the field of chemical imaging, combined chemical analysis has become attractive. This technique facilitates a deepened analysis compared to single techniques or side-by-side analysis. In this study, rat brains harvested one week after induction of photothrombotic stroke were investigated. Adjacent thin cuts from rats' brains were imaged using Fourier transform infrared (FT-IR) microspectroscopy and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The LA-ICP-MS data were normalized using an internal standard (a thin gold layer). The acquired hyperspectral data cubes were fused and subjected to multivariate analysis. Brain regions affected by stroke as well as unaffected gray and white matter were identified and classified using a model based on either partial least squares discriminant analysis (PLS-DA) or random decision forest (RDF) algorithms. The RDF algorithm demonstrated the best results for classification. Improved classification was observed in the case of fused data in comparison to individual data sets (either FT-IR or LA-ICP-MS). Variable importance analysis demonstrated that both molecular and elemental content contribute to the improved RDF classification. Univariate spectral analysis identified biochemical properties of the assigned tissue types. Classification of multisensor hyperspectral data sets using an RDF algorithm allows access to a novel and in-depth understanding of biochemical processes and solid chemical allocation of different brain regions.

  10. Deciphering diet and monitoring movement: Multiple stable isotope analysis of the viking age settlement at Hofstaðir, Lake Mývatn, Iceland.

    Science.gov (United States)

    Sayle, Kerry L; Hamilton, W Derek; Cook, Gordon T; Ascough, Philippa L; Gestsdóttir, Hildur; McGovern, Thomas H

    2016-05-01

    A previous multi-isotope study of archaeological faunal samples from Skútustaðir, an early Viking age settlement on the southern shores of Lake Mývatn in north-east Iceland, demonstrated that there are clear differences in δ(34)S stable isotope values between animals deriving their dietary protein from terrestrial, freshwater, and marine reservoirs. The aim of this study was to use this information to more accurately determine the diet of humans excavated from a nearby late Viking age churchyard. δ(13)C, δ(15)N, and δ(34)S analyses were undertaken on terrestrial animal (n = 39) and human (n = 46) bone collagen from Hofstaðir, a high-status Viking-period farmstead ∼10 km north-west of Skútustaðir. δ(34)S values for Hofstaðir herbivores were ∼6‰ higher relative to those from Skútustaðir (δ(34)S: 11.4 ± 2.3‰ versus 5.6 ± 2.8‰), while human δ(13)C, δ(15)N, and δ(34)S values were broad ranging (-20.2‰ to -17.3‰, 7.4‰ to 12.3‰, and 5.5‰ to 14.9‰, respectively). Results suggest that the baseline δ(34)S value for the Mývatn region is higher than previously predicted due to a possible sea-spray effect, but the massive deposition of Tanytarsus gracilentus (midges) (δ(34)S: -3.9‰) in the soil in the immediate vicinity of the lake is potentially lowering this value. Several terrestrial herbivores displayed higher bone collagen δ(34)S values than their contemporaries, suggesting trade and/or movement of animals to the region from coastal areas. Broad ranging δ(13)C, δ(15)N, and δ(34)S values for humans suggest the population were consuming varied diets, while outliers within the dataset could conceivably have been migrants to the area. © 2016 Wiley Periodicals, Inc.

  11. THERMOGRAVIMETRIC INVESTIGATION AND THERMAL CONVERSION KINETICS OF TYPICAL NORTH-AFRICA AND MIDDLE-EAST LIGNOCELLULOSIC WASTES

    Directory of Open Access Journals (Sweden)

    2012-01-01

    Full Text Available The aim of this work was to thermally characterize the renewable lignocellulosic bioresources derived from palm trees in order to highlight their energy potential. Pyrolysis and combustion behaviours of date stones (DS agricultural by-products were tested by thermo-gravimetric analysis, and the main chemical compositions were analyzed. The work has also been conducted to identify their most important physical characteristics. The study of the sizes and heating rate effects constitute the first part of the experimental work. Inert atmosphere and three heating rates: 10, 20, and 50 °C/min, were applied to various particle sizes of DS. In the second part, tests were carried out in an oxidizing atmosphere (21% O2 by varying the size of the DS. The kinetic parameters such as pre-exponential factor and activation energy were determined. Increasing the particle sizes and the heating rates didn’t have an appreciable influence on the global weight losses. However, degradation rates were significant with the porous structure of the DS. Weight losses in inert and oxidizing atmospheres were found to occur in two stages (drying and devolatilization and in three stages (drying, devolatilization, and oxidation of the char.

  12. Thermogravimetric kinetic modelling of in-situ catalytic pyrolytic conversion of rice husk to bioenergy using rice hull ash catalyst.

    Science.gov (United States)

    Loy, Adrian Chun Minh; Gan, Darren Kin Wai; Yusup, Suzana; Chin, Bridgid Lai Fui; Lam, Man Kee; Shahbaz, Muhammad; Unrean, Pornkamol; Acda, Menandro N; Rianawati, Elisabeth

    2018-04-07

    The thermal degradation behaviour and kinetic parameter of non-catalytic and catalytic pyrolysis of rice husk (RH) using rice hull ash (RHA) as catalyst were investigated using thermogravimetric analysis at four different heating rates of 10, 20, 50 and 100 K/min. Four different iso conversional kinetic models such as Kissinger, Friedman, Kissinger-Akahira-Sunose (KAS) and Ozawa-Flynn-Wall (OFW) were applied in this study to calculate the activation energy (E A ) and pre-exponential value (A) of the system. The E A of non-catalytic and catalytic pyrolysis was found to be in the range of 152-190 kJ/mol and 146-153 kJ/mol, respectively. The results showed that the catalytic pyrolysis of RH had resulted in a lower E A as compared to non-catalytic pyrolysis of RH and other biomass in literature. Furthermore, the high Gibb's free energy obtained in RH implied that it has the potential to serve as a source of bioenergy production. Copyright © 2018 Elsevier Ltd. All rights reserved.

  13. Comparative study on pyrolysis of lignocellulosic and algal biomass using a thermogravimetric and a fixed-bed reactor.

    Science.gov (United States)

    Yuan, Ting; Tahmasebi, Arash; Yu, Jianglong

    2015-01-01

    Pyrolysis characteristics of four algal and lignocellulosic biomass samples were studied by using a thermogravimetric analyzer (TGA) and a fixed-bed reactor. The effects of pyrolysis temperature and biomass type on the yield and composition of pyrolysis products were investigated. The average activation energy for pyrolysis of biomass samples by FWO and KAS methods in this study were in the range of 211.09-291.19kJ/mol. CO2 was the main gas component in the early stage of pyrolysis, whereas H2 and CH4 concentrations increased with increasing pyrolysis temperature. Bio-oil from Chlorellavulgaris showed higher content of nitrogen containing compounds compared to lignocellulosic biomass. The concentration of aromatic organic compounds such as phenol and its derivatives were increased with increasing pyrolysis temperature up to 700°C. FTIR analysis results showed that with increasing pyrolysis temperature, the concentration of OH, CH, CO, OCH3, and CO functional groups in char decreased sharply. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Differential thermal, Thermogravimetric and X-ray diffraction investigation of hydration phases in cementitious waste form

    International Nuclear Information System (INIS)

    Khalil, M.Y.; Nagy, M.E.; El-Sourougy, M.R.; Zaki, A.A.

    1996-01-01

    Hydration phases of cement determine the final properties of the product. Adding other components to the cement paste may alter the final phases formed and affect properties of the hardened products. In this work ordinary portland cement and/or blast furnace slag cement were hardened with low-or intermediate-level radioactive liquid wastes and different additives. Hydration phases were investigated using differential thermal, thermogravimetric, and X-ray diffraction techniques. Low-and intermediate-level liquid wastes were found not to affect the hydration phases of cement. The addition of inorganic exchangers and latex were found to affect the hydration properties of the cement waste system. This resulted in a reduction of compressive strength. On the contrary, addition of epoxy also affected the hydration causing increase in compressive strength. 10 figs., 2 tabs

  15. Thermogravimetric study of the pyrolysis of biomass residues from tomato processing industry

    Energy Technology Data Exchange (ETDEWEB)

    Mangut, V.; Sabio, E.; Ganan, J.; Gonzalez, J.F.; Ramiro, A.; Gonzalez, C.M.; Roman, S.; Al-Kassir, A. [Department of Chemical and Energy Engineering, University of Extremadura, Avda. de Elvas s/n, 06071 Badajoz (Spain)

    2006-01-15

    There is an increasing concern with the environmental problems associated with the increasing CO{sub 2}, NO{sub x} and SO{sub x} emissions resulting from the rising use of fossil fuels. Renewable energy, mainly biomass, can contribute to reduce the fossil fuels consumption. Biomass is a renewable resource with a widespread world distribution. Tomato processing industry produces a high amount of biomass residue (peel and seeds) that could be used for thermal energy and electricity. A characterization and thermogravimetric study has been carried out. The residue has a high HHV and volatile content, and a low ash, and S contents. A kinetic model has been developed based on the degradation of hemicellulose, cellulose, lignin and oil that describe the pyrolysis of peel, seeds and peel and seeds residues. (author)

  16. Thermogravimetric characteristics of typical municipal solid waste fractions during co-pyrolysis.

    Science.gov (United States)

    Zhou, Hui; Long, YanQiu; Meng, AiHong; Li, QingHai; Zhang, YanGuo

    2015-04-01

    The interactions of nine typical municipal solid waste (MSW) fractions during pyrolysis were investigated using the thermogravimetric analyzer (TGA). To compare the mixture results with the calculation results of superposition of single fractions quantitatively, TG overlap ratio was introduced. There were strong interactions between orange peel and rice (overlap ratio 0.9736), and rice and poplar wood (overlap ratio 0.9774). The interactions of mixture experiments postponed the peak and lowered the peak value. Intense interactions between PVC and rice, poplar wood, tissue paper, wool, terylene, and rubber powder during co-pyrolysis were observed, and the pyrolysis at low temperature was usually promoted. The residue yield was increased when PVC was blended with rice, poplar wood, tissue paper, or rubber powder; while the residue yield was decreased when PVC was blended with wool. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Thermogravimetric kinetics of corn stalk pretreated by oleaginous fungi Cunninghamella echinulata.

    Science.gov (United States)

    Wu, Jianguo; Gao, Shi; Wan, Jilin; Zeng, Yelin; Ma, Fuying; Zhang, Xiaoyu

    2011-04-01

    The thermogravimetric and composition of corn stalk pretreated by oleaginous fungi Cunninghamella echinulata had been studied in this paper. Results indicated that pretreatment by oleaginous fungi C. echinulata could decrease the activation energy and make the pyrolysis more efficient and energy-saving. By bio-pretreatment, the contents of elements agreed with the weight loss, sugar content, and oil contents, especially the sulfur content was greatly decreased, greatly eliminating the inventory of gas contamination such as the emission of SOx and making the pyrolysis more environmentally friendly. Therefore, corn stalk with sugar pretreated by oleaginous fungi C. echinulata should be a good pyrolysis material to obtain high quality bio-oil. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Thermogravimetric and x-ray diffraction analyses of Luna-24 regolith samples

    International Nuclear Information System (INIS)

    Deshpande, V.V.; Dharwadkar, S.R.; Jakkal, V.S.

    1979-01-01

    Two samples of Luna-24 were analysed by X-ray diffraction and thermogravimetric (TG) techniques. The sample 24123.12 shows a weight loss of nearly 0.85 percent between 23O-440deg C and followed by 1.16 percent weight gain from 500 to 800deg C. The sample 23190.13 showed only a weight gain of about 1.5 percent from 5O0deg C to 900deg C. X-ray diffraction analyses show the presence of olivine, plagioclase, pigeonite, enstatite, and native iron in both the virgin samples. The heated samples, however, show that only the native iron got oxidized to iron oxide. The other constituents remain unaltered. (auth.)

  19. Thermogravimetric investigation on characteristic of biomass combustion under the effect of organic calcium compounds.

    Science.gov (United States)

    Zhang, Lihui; Duan, Feng; Huang, Yaji

    2015-01-01

    Experiments were conducted in a thermogravimetric analyzer to investigate thermal behavior of different organic calcium compounds (OCCs) and its blended fuels with three kinds of biomass. The effectiveness of synthesized method for OCC was assessed by the pyrolysis test. Effect of the mole ratio of calcium to sulfur on co-combustion characteristics was studied. Results indicated that preparation method of modified calcium acetate (MCA) had high precision and accuracy. Co-combustion characteristic of OCCs blended with biomass was controlled by OCCs' additive amount and the content of volatile matter which is mainly composed of small hydrocarbon molecules. Combustion performance indexes for peanut shell and wheat straw impregnated by OCCs were improved, however, an inverse trend was found for rice husk because of lower additive amount of OCCs. The blended fuel show higher combustion performance indexes compared with combustion of individual biomass, and these indexes decrease with increases of Ca/S ratio. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. A vacuum thermogravimetric method for outgassing evaluations of silicone-coated fiberglass cloth

    Science.gov (United States)

    Jensen, L. B.; Mccauley, G. B.; Honma, M.; Hultquist, A. E.

    1972-01-01

    A method for evaluating outgassing characteristics of space-sensitive materials was devised by modifying a thermogravimetric balance so that a continual weight loss trace is obtained as a function of time at constant temperature and nearly constant pressure. In addition the apparatus is capable of collecting room temperature condensibles during the outgassing run. A series of silicone-coated glass cloth samples were evaluated by this method. The major advantage of the technique is that data presentation is developed in the form of a continuous trace. This data can then be utilized to develop the kinetics of weight loss. The technique has been shown to be a useful and valid one for indicating small differences between materials under vacuum and elevated temperature conditions.

  1. Thermogravimetric analytical procedures for determining reactivities of chars from New Zealand coals

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, K.J.; Beamish, B.B.; Rodgers, K.A. [University of Auckland, Auckland (New Zealand). Dept. of Geology

    1997-10-22

    This paper describes how tightly constrained thermogravimetric experimental procedures (particle size {lt} 212 {mu}m, sample mass 15.5 mg, CO{sub 2} reactant gas, near isothermal conditions) allow the reactivity of chars from high volatile New Zealand coals to be determined to a repeatability of {+-}0.07 h{sup -1} at 900{degree}C and {+-}0.5 h{sup -1} at 1100{degree}C. The procedure also provides proximate analyses information and affords a quick ({lt} 90 min) comparison between different coal types as well as indicating likely operating conditions and problems associated with a particular coal or blend. A clear difference is evident between reactivities of differing New Zealand coal ranks. Between 900 and 1100{degree}C, bituminous coals increase thirtyfold in reactivity compared with fourfold for subbituminous, with the latter being three to five times greater in reactivity at higher temperature.

  2. The Effect of Radiation Timing on Patients With High-Risk Features of Parameningeal Rhabdomyosarcoma: An Analysis of IRS-IV and D9803

    Energy Technology Data Exchange (ETDEWEB)

    Spalding, Aaron C., E-mail: Aaron.Spalding@nortonhealthcare.org [Kosair Children' s Hospital and Brain Tumor Center, Louisville, Kentucky (United States); Hawkins, Douglas S. [Division of Hematology/Oncology, Seattle Children' s Hospital, and Fred Hutchinson Cancer Research Center, University of Washington, Seattle, Washington (United States); Donaldson, Sarah S. [Department of Radiation Oncology, Stanford University Medical Center, Stanford, California (United States); Anderson, James R.; Lyden, Elizabeth [University of Nebraska Medical Center, Omaha, Nebraska (United States); Laurie, Fran [Quality Assurance Review Center, Providence, Rhode Island and Seattle, Washington (United States); Wolden, Suzanne L. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Arndt, Carola A.S. [Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota (United States); Michalski, Jeff M. [Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri (United States)

    2013-11-01

    Purpose: Radiation therapy remains an essential treatment for patients with parameningeal rhabdomyosarcoma (PMRMS), and early radiation therapy may improve local control for patients with intracranial extension (ICE). Methods and Materials: To address the role of radiation therapy timing in PMRMS in the current era, we reviewed the outcome from 2 recent clinical trials for intermediate-risk RMS: Intergroup Rhabdomyosarcoma Study (IRS)-IV and Children's Oncology Group (COG) D9803. The PMRMS patients on IRS-IV with any high-risk features (cranial nerve palsy [CNP], cranial base bony erosion [CBBE], or ICE) were treated immediately at day 0, and PMRMS patients without any of these 3 features received week 6-9 radiation therapy. The D9803 PMRMS patients with ICE received day 0 X-Ray Therapy (XRT) as well; however, those with either CNP or CBBE had XRT at week 12. Results: Compared with the 198 PMRMS patients from IRS-IV, the 192 PMRMS patients from D9803 had no difference (P<.05) in 5-year local failure (19% vs 19%), failure-free-survival (70% vs 67%), or overall survival (75% vs 73%) in aggregate. The 5-year local failure rates by subset did not differ when patients were classified as having no risk features (None, 15% vs 19%, P=.25), cranial nerve palsy/cranial base of skull erosion (CNP/CBBE, 15% vs 28%, P=.22), or intracranial extension (ICE, 21% vs 15%, P=.27). The D9083 patients were more likely to have received initial staging by magnetic resonance imaging (71% vs 53%). Conclusions: These data support that a delay in radiation therapy for high-risk PMRMS features of CNP/CBBE does not compromise clinical outcomes.

  3. Synthesis, Spectral, Thermogravimetric, XRD, Molecular Modelling and Potential Antibacterial Studies of Dimeric Complexes with Bis Bidentate ON–NO Donor Azo Dye Ligands

    Directory of Open Access Journals (Sweden)

    Bipin Bihari Mahapatra

    2013-01-01

    Full Text Available The dimeric complexes of Co(II, Ni(II, Cu(II, Zn(II, Cd(II, and Hg(II with two new symmetrical ON–NO donor bis bidentate (tetradentate azo dye ligands, LH2 = 4,4′-bis(4′-hydroxyquinolinolinylazodiphenylsulphone, and L′H2 = 4,4′-bis(acetoacetanilideazodiphenylsulphone have been synthesized. The metal complexes have been characterised by elemental analytical, conductance, magnetic susceptibility, IR, electronic spectra, ESR, NMR, thermogravimetry, X-ray diffraction (powder pattern spectra, and molecular modelling studies. The Co(II and Ni(II complexes are found to be octahedral, Cu(II complexes are distorted octahedral, and a tetrahedral stereochemistry has been assigned to Zn(II, Cd(II, and Hg(II complexes. The thermogravimetric study indicates that compounds are quite stable. The energy optimized structures are proposed using the semiempirical ZINDO/1 quantum mechanical calculations. The potential antibacterial study of the ligands and some metal complexes has been made with one gram positive bacteria Staphylococcus aureus and one gram negative bacteria E. coli which gives encouraging results. Both the Co(II complexes are found to possess monoclinic crystal system.

  4. An Analysis of the Microstructure, Macrostructure and Microhardness of Nicr-Ir Joints Produced by Laser Welding with and without Preheat

    Directory of Open Access Journals (Sweden)

    Różowicz S.

    2016-06-01

    Full Text Available This paper discusses some of the basic problems involved in laser welding of dissimilar materials with significant differences in melting points. It focuses on the micro and macrostructure of laser welded NiCr-Ir microjoints used in central spark plug electrodes. The joints were produced by welding with and without preheat using an Nd,YAG laser. The structure and composition of the welded joints were analyzed by means of a light microscope (LM and a scanning electron microscope (SEM equipped with an energy dispersive X-ray (EDX spectrometer. The microhardness of the weld area was also studied.

  5. Development of pixellated Ir-TESs

    Science.gov (United States)

    Zen, Nobuyuki; Takahashi, Hiroyuki; Kunieda, Yuichi; Damayanthi, Rathnayaka M. T.; Mori, Fumiakira; Fujita, Kaoru; Nakazawa, Masaharu; Fukuda, Daiji; Ohkubo, Masataka

    2006-04-01

    We have been developing Ir-based pixellated superconducting transition edge sensors (TESs). In the area of material or astronomical applications, the sensor with few eV energy resolution and over 1000 pixels imaging property is desired. In order to achieve this goal, we have been analyzing signals from pixellated TESs. In the case of a 20 pixel array of Ir-TESs, with 45 μm×45 μm pixel sizes, the incident X-ray signals have been classified into 16 groups. We have applied numerical signal analysis. On the one hand, the energy resolution of our pixellated TES is strongly degraded. However, using pulse shape analysis, we can dramatically improve the resolution. Thus, we consider that the pulse signal analysis will lead this device to be used as a practical photon incident position identifying TES.

  6. Development of pixellated Ir-TESs

    International Nuclear Information System (INIS)

    Zen, Nobuyuki; Takahashi, Hiroyuki; Kunieda, Yuichi; Dayanthi, Rathnayaka M.T.; Mori, Fumiakira; Fujita, Kaoru; Nakazawa, Masaharu; Fukuda, Daiji; Ohkubo, Masataka

    2006-01-01

    We have been developing Ir-based pixellated superconducting transition edge sensors (TESs). In the area of material or astronomical applications, the sensor with few eV energy resolution and over 1000 pixels imaging property is desired. In order to achieve this goal, we have been analyzing signals from pixellated TESs. In the case of a 20 pixel array of Ir-TESs, with 45 μmx45 μm pixel sizes, the incident X-ray signals have been classified into 16 groups. We have applied numerical signal analysis. On the one hand, the energy resolution of our pixellated TES is strongly degraded. However, using pulse shape analysis, we can dramatically improve the resolution. Thus, we consider that the pulse signal analysis will lead this device to be used as a practical photon incident position identifying TES

  7. Thermogravimetric determination of the carbon dioxide reactivity of char from some New Zealand coals and its association with the inorganic geochemistry of the parent coal

    Energy Technology Data Exchange (ETDEWEB)

    Beamish, B.B.; Shaw, K.J.; Rodgers, K.A.; Newman, J. [University of Auckland, Auckland (New Zealand). Dept. of Geology

    1998-02-01

    Thermogravimetrically-determined carbon dioxide reactivities of char formed from New Zealand coals, ranging in rank from lignite to high volatile bituminous, vary from 0.12 to 10.63 mg/h/mg on a dry, ash-free basis. The lowest rank subbituminous coal chars have similar reactivities to the lignite coal chars. Calcium content of the char shows the strongest correlation with reactivity, which increases as the calcium content increases. High calcium per se does not directly imply a high char reactivity. Organically-bound calcium catalyses the conversion of carbon to carbon monoxide in the presence of carbon dioxide, whereas calcium present as discrete minerals in the coal matrix e.g., calcite, fails to significantly affect reactivity. Catalytic effects of magnesium, iron, sodium and phosphorous are not as obvious, but can be recognised for individual chars. The thermogravimetric technique provides a fast, reliable analysis that is able to distinguish char reactivity differences between coals, which may be due to any of the above effects. 27 refs., 6 figs., 4 tabs.

  8. Molten salt corrosion behavior of structural materials in LiCl-KCl-UCl3 by thermogravimetric study

    Science.gov (United States)

    Rao, Ch Jagadeeswara; Ningshen, S.; Mallika, C.; Mudali, U. Kamachi

    2018-04-01

    The corrosion resistance of structural materials has been recognized as a key issue in the various unit operations such as salt purification, electrorefining, cathode processing and injection casting in the pyrochemical reprocessing of spent metallic nuclear fuels. In the present work, the corrosion behavior of the candidate materials of stainless steel (SS) 410, 2.25Cr-1Mo and 9Cr-1Mo steels was investigated in molten LiCl-KCl-UCl3 salt by thermogravimetric analysis under inert and reactive atmospheres at 500 and 600 °C, for 6 h duration. Insignificant weight gain (less than 1 mg/cm2) in the inert atmosphere and marginal weight gain (maximum 5 mg/cm2) in the reactive atmosphere were observed at both the temperatures. Chromium depletion rates and formation of Cr-rich corrosion products increased with increasing temperature of exposure in both inert and reactive atmospheres as evidenced by SEM and EDS analysis. The corrosion attack by LiCl-KCl-UCl3 molten salt, under reactive atmosphere for 6 h duration was more in the case of SS410 than 9Cr-1Mo steel followed by 2.25Cr-1Mo steel at 500 °C and the corrosion attack at 600 °C followed the order: 9Cr-1Mo steel >2.25Cr-1Mo steel > SS410. Outward diffusion of the minor alloying element, Mo was observed in 9Cr-1Mo and 2.25Cr-1Mo steels at both temperatures under reactive atmosphere. Laser Raman spectral analysis of the molten salt corrosion tested alloys under a reactive atmosphere at 500 and 600 °C for 6 h revealed the formation of unprotected Fe3O4 and α-as well as γ-Fe2O3. The results of the present study facilitate the selection of structural materials for applications in the corrosive molten salt environment at high temperatures.

  9. FT-IR, FT-Raman spectra, density functional computations of the vibrational spectra and molecular conformational analysis of 2,5-di-tert-butyl-hydroquinone

    Science.gov (United States)

    Subramanian, N.; Sundaraganesan, N.; Dereli, Ö.; Türkkan, E.

    2011-12-01

    The purpose of finding conformer among six different possible conformers of 2,5-di-tert-butyl-hydroquinone (DTBHQ), its equilibrium geometry and harmonic wavenumbers were calculated by the B3LYP/6-31G(d,p) method. The infrared and Raman spectra of DTBHQ were recorded in the region 400-4000 cm -1 and 50-3500 cm -1, respectively. In addition, the IR spectra in CCl 4 at various concentrations of DTBHQ are also recorded. The computed vibrational wavenumbers were compared with the IR and Raman experimental data. Computational calculations at B3LYP level with two different basis sets 6-31G(d,p) and 6-311++G(d,p) are also employed in the study of the possible conformer of DTBHQ. The complete assignments were performed on the basis of the potential energy distribution (PED) of the vibrational modes, calculated using VEDA 4 program. The general agreement between the observed and calculated frequencies was established.

  10. Preliminary Analysis of IR Cloudtop Temperatures of Sprite Producing Storms over Argentina Observed from Brazil, and Comparison with US Case Study

    Science.gov (United States)

    Sao Sabbas, F. T.; Pautet, P.; Taylor, M. J.; Pinto, O.; Thomas, J.; Solorzano, N.; Holzworth, R.; Bailey, M.; Schuch, N.; Michels, M.

    2006-12-01

    We will present the preliminary results of the cloudtop temperature characteristics of two very active sprite- producing Mesoscale Convective System (MCS) which occurred over Argentina in the evening of February 22, and March 04, 2006. These were prolific storms, e.g. the first one produced more than 400 TLEs, including sprites, halos and possibly elves. The events were observed from the INPE Observatorio Espacial Sul-OES (Southern Space Observatory), located at the center of Rio Grande do Sul State, the most Southern State of Brazil. Except for the lack of triangulated locations for the sprites and halos recorded, the methodology used for this study is the same as for the paper Sao Sabbas and Sentman [2003], where a sprite producing storm over the central U.S. was observed during the night of July 22, 1996. We analyzed the IR satellite data provided by GOES-12 and the lightning information from the Brazilian Lightning Detection Network in combination with data from the World Wide Lightning Location Network WWLLN. We will also show a comparison between the obtained results and the results presented at the Sao Sabbas and Sentman [2003] paper. Sao Sabbas, F.T. and D. D. Sentman, Dynamical Relationship of IR Cloudtop Temperatures With Occurrence Rates of Cloud-to-Ground Lightning and Sprites, Geophys. Res. Lett., 30 (5), 40-1-40-4, 2003.

  11. A thermogravimetric analyzer for corrosive atmospheres, and its application to the chlorination of ZrO2-C mixtures

    International Nuclear Information System (INIS)

    Pasquevich, Daniel; Caneiro, Alberto

    1990-01-01

    A thermogravimetric analyzer built on the basis of a Cahn 2000 electrobalance, suitable for using with corrosive atmospheres, is reported. The corrections for buoyancy and gas-flow effects, which strongly modify the thermogravimetric curves are discussed. As an application, the kinetics of a reaction between chlorine and a mixture of zirconia and carbon has been studied. It has been able to measure the uptake of chlorine by carbon and the reaction rate within the first 50 seconds. Evidence of a transition to quite a different reaction rate at longer times is presented. (Author)

  12. Thermogravimetric and microscopic analysis of SiC/SiC materials with advanced interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Windisch, C.F. Jr.; Jones, R.H. [Pacific Northwest National Lab., Richland, WA (United States); Snead, L.L. [Oak Ridge National Lab., TN (United States)

    1997-04-01

    The chemical stability of SiC/SiC composites with fiber/matrix interfaces consisting of multilayers of SiC/SiC and porous SiC have been evaluated using a thermal gravimetric analyzer (TGA). Previous evaluations of SiC/SiC composites with carbon interfacial layers demonstrated the layers are not chemically stable at goal use temperatures of 800-1100{degrees}C and O{sub 2} concentrations greater than about 1 ppm. No measureable mass change was observed for multilayer and porous SiC interfaces at 800-1100{degrees}C and O{sub 2} concentrations of 100 ppm to air; however, the total amount of oxidizable carbon is on the order of the sensitivity of the TGA. Further studies are in progress to evaluate the stability of these materials.

  13. Thermogravimetric study and kinetic analysis of fungal pretreated corn stover using the distributed activation energy model.

    Science.gov (United States)

    Ma, Fuying; Zeng, Yelin; Wang, Jinjin; Yang, Yang; Yang, Xuewei; Zhang, Xiaoyu

    2013-01-01

    Non-isothermal thermogravimetry/derivative thermogravimetry (TG/DTG) measurements are used to determine pyrolytic characteristics and kinetics of lignocellulose. TG/DTG experiments at different heating rates with corn stover pretreated with monocultures of Irpex lacteus CD2 and Auricularia polytricha AP and their cocultures were conducted. Heating rates had little effect on the pyrolysis process, but the peak of weight loss rate in the DTG curves shifted towards higher temperature with heating rate. The maximum weight loss of biopretreated samples was 1.25-fold higher than that of the control at the three heating rates, and the maximum weight loss rate of the co-culture pretreated samples was intermediate between that of the two mono-cultures. The activation energies of the co-culture pretreated samples were 16-72 kJ mol(-1) lower than that of the mono-culture at the conversion rate range from 10% to 60%. This suggests that co-culture pretreatment can decrease activation energy and accelerate pyrolysis reaction thus reducing energy consumption. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Discernment of synergism in pyrolysis of biomass blends using thermogravimetric analysis.

    Science.gov (United States)

    Mallick, Debarshi; Poddar, Maneesh Kumar; Mahanta, Pinakeswar; Moholkar, Vijayanand S

    2018-04-12

    This study reports pyrolysis kinetics of biomass blends using isoconversional methods, viz. Friedman, FWO and KAS. Blends of three biomasses, viz. saw dust, bamboo dust and rice husk, were used. Extractives and volatiles in biomass and minerals in ash had marked influence on enhancement of reaction kinetics during co-pyrolysis, as indicated by reduction in activation energy and increase in decomposition intensity. Pyrolysis kinetics of saw dust and rice husk accelerated (positive synergy), while that of bamboo dust decelerated after blending (negative synergy). Predominant reaction mechanism of all biomass blends was 3-D diffusion in lower conversion range (α ≤ 0.5), while for α ≥ 0.5 pyrolysis followed random nucleation (or nucleation and growth mechanism). Higher reaction order for pyrolysis of blends of rice husk with saw dust and bamboo dust was attributed to catalytic effect of minerals in ash. Positive ΔH and ΔG was obtained for pyrolysis of all biomass blends. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. Analysis of unburned carbon in industrial ashes from biomass combustion by thermogravimetric method using Boudouard reaction

    Czech Academy of Sciences Publication Activity Database

    Straka, Pavel; Náhunková, Jana; Žaloudková, Margit

    2014-01-01

    Roč. 575, JAN (2014), s. 188-194 ISSN 0040-6031 R&D Projects: GA MZe QI102A207 Institutional support: RVO:67985891 Keywords : unburned carbon * biomass * ash * thermogravimetry Subject RIV: GD - Fertilization, Irrigation, Soil Processing Impact factor: 2.184, year: 2014 http://www.sciencedirect.com/science/article/pii/S0040603113005455

  16. Electronic [UV-Visible] and vibrational [FT-IR, FT-Raman] investigation and NMR-mass spectroscopic analysis of terephthalic acid using quantum Gaussian calculations

    Science.gov (United States)

    Karthikeyan, N.; Joseph Prince, J.; Ramalingam, S.; Periandy, S.

    2015-03-01

    In this research work, the vibrational IR, polarization Raman, NMR and mass spectra of terephthalic acid (TA) were recorded. The observed fundamental peaks (IR, Raman) were assigned according to their distinctiveness region. The hybrid computational calculations were carried out for calculating geometrical and vibrational parameters by DFT (B3LYP and B3PW91) methods with 6-31++G(d,p) and 6-311++G(d,p) basis sets and the corresponding results were tabulated. The molecular mass spectral data related to base molecule and substitutional group of the compound was analyzed. The modification of the chemical property by the reaction mechanism of the injection of dicarboxylic group in the base molecule was investigated. The 13C and 1H NMR spectra were simulated by using the gauge independent atomic orbital (GIAO) method and the absolute chemical shifts related to TMS were compared with experimental spectra. The study on the electronic and optical properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, were performed by hybrid Gaussian calculation methods. The orbital energies of different levels of HOMO and LUMO were calculated and the molecular orbital lobe overlapping showed the inter charge transformation between the base molecule and ligand group. From the frontier molecular orbitals (FMO), the possibility of electrophilic and nucleophilic hit also analyzed. The NLO activity of the title compound related to Polarizability and hyperpolarizability were also discussed. The present molecule was fragmented with respect to atomic mass and the mass variation depends on the substitutions have also been studied.

  17. Brachytherapy source calibration, reviews, and consistency of 192Ir high-dose rate afterloading sources supplied over the period of 10 years: a retrospective analysis

    International Nuclear Information System (INIS)

    Nagappan, Balasubramanian; Kumar, Yogesh; Patel, Narayan P.; Dhull, Anil Kumar; Kaushal, Vivek

    2015-01-01

    Measurement and verification of strength of monomodal high-dose rate (mHDR) 192 Ir source supplied by the vendor is a major part of quality assurance program. Reference air kerma rate (RAKR) or air kerma strength (AKS) is the recommended quantity to specify the strength of gamma emitting brachytherapy sources. Physicist in our institution performed the source calibration as soon as each 192 Ir new source was loaded on the mHDR afterloading machine. The AKS accurately measured using a physikalisch technische werkstatten (PTW) re-entrant chamber-electrometer system in a scatter-free geometry was used to compute the air kerma rate (AKR) at one-meter distance in the air. To ensure accurate dose delivery to brachytherapy patients, measured AKS or RAKR should be entered correctly in both HDR treatment console station (TCS) as well as treatment planning system (TPS) associated with it. The clinical outcome mainly depends not only on the accuracy of the source strength measurement in the hospital but also on the correct source strength entered into both TCS and TPS software. A retrospective study on 22 mHDR V2 sources supplied by the vendor for the period of 10 years was taken up to access the accuracy of source strength supplied to the Radiotherapy department. The results are analyzed and reported. The accuracy in measured RAKR of all 22 sources supplied by vendor was well within the tolerance limits set by the national regulatory body and international recommendations. The deviations observed between measured RAKR versus manufacturer's quoted RAKR were in the range from -1.71% to +1.15%. In conclusion, the measured RAKR have good agreement with vendor quoted RAKR values. (author)

  18. Measurement and analysis of the excitation function and isomeric cross section ratios for α-induced reaction on Ir, Au, Re and Ta nuclei

    International Nuclear Information System (INIS)

    Ismail, M.

    1998-01-01

    Excitation functions and a few isomeric cross section ratios for production of (1) 192 Au, 193 Au, 194 Au, 195 Au and 192 Ir nuclides in α-induced reactions on 191,193 Ir, (2) 197 Tl, 197m Hg, 198m.g Tl, 199 Tl and 200 Tl nuclides in α-induced reaction in 197 Au and (3) 183 Re and 184m.g Re nuclides in α-induced reaction in 181 Ta and 185 Re are obtained from the measurements of the residual activities by the conventional stacked-foils technique from threshold to 50 MeV. The excitation function and isomeric cross section ratios for nuclear reaction 181 Ta (α,n) 184m.g Re are compared with the theoretical calculation using the code Stapre which is based on exciton model for pre-equilibrium phase and Hauser-Feshbach formalism taking angular momentum and parity into account for the equilibrium phase of the nuclear reaction. All other experimental excitation functions are compared with the calculations considering equilibrium as well as pre-equilibrium reaction mechanism according to the geometry dependent hybrid (GDH) model and hybrid model of Blann using the code Alice/91. The high energy part of the excitation functions are dominated by pre-equilibrium reaction mechanism whereas the low energy parts are dominated by equilibrium evaporation with its characteristic peak. The GDH model provides a potentially better description of the physical process (i.e. a higher probability for peripheral collisions to undergo precompound decay than for central collisions) compared to hybrid model. However in the energy range of present measurement most of the excitation functions are fitted reasonably well by both GDH model and hybrid model with initial exciton number N 0 =4 (N n =2, N p =2, N h =0). Barring a few reactions we have found the overall agreement between theory and experiment is reasonably good taking the limitations of the theory into account. (author)

  19. Electronic [UV-Visible] and vibrational [FT-IR, FT-Raman] investigation and NMR-mass spectroscopic analysis of terephthalic acid using quantum Gaussian calculations.

    Science.gov (United States)

    Karthikeyan, N; Prince, J Joseph; Ramalingam, S; Periandy, S

    2015-03-15

    In this research work, the vibrational IR, polarization Raman, NMR and mass spectra of terephthalic acid (TA) were recorded. The observed fundamental peaks (IR, Raman) were assigned according to their distinctiveness region. The hybrid computational calculations were carried out for calculating geometrical and vibrational parameters by DFT (B3LYP and B3PW91) methods with 6-31++G(d,p) and 6-311++G(d,p) basis sets and the corresponding results were tabulated. The molecular mass spectral data related to base molecule and substitutional group of the compound was analyzed. The modification of the chemical property by the reaction mechanism of the injection of dicarboxylic group in the base molecule was investigated. The (13)C and (1)H NMR spectra were simulated by using the gauge independent atomic orbital (GIAO) method and the absolute chemical shifts related to TMS were compared with experimental spectra. The study on the electronic and optical properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, were performed by hybrid Gaussian calculation methods. The orbital energies of different levels of HOMO and LUMO were calculated and the molecular orbital lobe overlapping showed the inter charge transformation between the base molecule and ligand group. From the frontier molecular orbitals (FMO), the possibility of electrophilic and nucleophilic hit also analyzed. The NLO activity of the title compound related to Polarizability and hyperpolarizability were also discussed. The present molecule was fragmented with respect to atomic mass and the mass variation depends on the substitutions have also been studied. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

  20. Cluster pattern analysis of energy deposition sites for the brachytherapy sources 103Pd, 125I, 192Ir, 137Cs, and 60Co.

    Science.gov (United States)

    Villegas, Fernanda; Tilly, Nina; Bäckström, Gloria; Ahnesjö, Anders

    2014-09-21

    Analysing the pattern of energy depositions may help elucidate differences in the severity of radiation-induced DNA strand breakage for different radiation qualities. It is often claimed that energy deposition (ED) sites from photon radiation form a uniform random pattern, but there is indication of differences in RBE values among different photon sources used in brachytherapy. The aim of this work is to analyse the spatial patterns of EDs from 103Pd, 125I, 192Ir, 137Cs sources commonly used in brachytherapy and a 60Co source as a reference radiation. The results suggest that there is both a non-uniform and a uniform random component to the frequency distribution of distances to the nearest neighbour ED. The closest neighbouring EDs show high spatial correlation for all investigated radiation qualities, whilst the uniform random component dominates for neighbours with longer distances for the three higher mean photon energy sources (192Ir, 137Cs, and 60Co). The two lower energy photon emitters (103Pd and 125I) present a very small uniform random component. The ratio of frequencies of clusters with respect to 60Co differs up to 15% for the lower energy sources and less than 2% for the higher energy sources when the maximum distance between each pair of EDs is 2 nm. At distances relevant to DNA damage, cluster patterns can be differentiated between the lower and higher energy sources. This may be part of the explanation to the reported difference in RBE values with initial DSB yields as an endpoint for these brachytherapy sources.

  1. Multiwaveband simulation-based signature analysis of camouflaged human dismounts in cluttered environments with TAIThermIR and MuSES

    Science.gov (United States)

    Packard, Corey D.; Klein, Mark D.; Viola, Timothy S.; Hepokoski, Mark A.

    2016-10-01

    The ability to predict electro-optical (EO) signatures of diverse targets against cluttered backgrounds is paramount for signature evaluation and/or management. Knowledge of target and background signatures is essential for a variety of defense-related applications. While there is no substitute for measured target and background signatures to determine contrast and detection probability, the capability to simulate any mission scenario with desired environmental conditions is a tremendous asset for defense agencies. In this paper, a systematic process for the thermal and visible-through-infrared simulation of camouflaged human dismounts in cluttered outdoor environments is presented. This process, utilizing the thermal and EO/IR radiance simulation tool TAIThermIR (and MuSES), provides a repeatable and accurate approach for analyzing contrast, signature and detectability of humans in multiple wavebands. The engineering workflow required to combine natural weather boundary conditions and the human thermoregulatory module developed by ThermoAnalytics is summarized. The procedure includes human geometry creation, human segmental physiology description and transient physical temperature prediction using environmental boundary conditions and active thermoregulation. Radiance renderings, which use Sandford-Robertson BRDF optical surface property descriptions and are coupled with MODTRAN for the calculation of atmospheric effects, are demonstrated. Sensor effects such as optical blurring and photon noise can be optionally included, increasing the accuracy of detection probability outputs that accompany each rendering. This virtual evaluation procedure has been extensively validated and provides a flexible evaluation process that minimizes the difficulties inherent in human-subject field testing. Defense applications such as detection probability assessment, camouflage pattern evaluation, conspicuity tests and automatic target recognition are discussed.

  2. CCD and IR array controllers

    Science.gov (United States)

    Leach, Robert W.; Low, Frank J.

    2000-08-01

    A family of controllers has bene developed that is powerful and flexible enough to operate a wide range of CCD and IR focal plane arrays in a variety of ground-based applications. These include fast readout of small CCD and IR arrays for adaptive optics applications, slow readout of large CCD and IR mosaics, and single CCD and IR array operation at low background/low noise regimes as well as high background/high speed regimes. The CCD and IR controllers have a common digital core based on user- programmable digital signal processors that are used to generate the array clocking and signal processing signals customized for each application. A fiber optic link passes image data and commands to VME or PCI interface boards resident in a host computer to the controller. CCD signal processing is done with a dual slope integrator operating at speeds of up to one Megapixel per second per channel. Signal processing of IR arrays is done either with a dual channel video processor or a four channel video processor that has built-in image memory and a coadder to 32-bit precision for operating high background arrays. Recent developments underway include the implementation of a fast fiber optic data link operating at a speed of 12.5 Megapixels per second for fast image transfer from the controller to the host computer, and supporting image acquisition software and device drivers for the PCI interface board for the Sun Solaris, Linux and Windows 2000 operating systems.

  3. Quantum mechanical study and spectroscopic (FT-IR, FT-Raman, UV-Visible) study, potential energy surface scan, Fukui function analysis and HOMO-LUMO analysis of 3-tert-butyl-4-methoxyphenol by DFT methods.

    Science.gov (United States)

    Saravanan, S; Balachandran, V

    2014-09-15

    This study represents an integral approach towards understanding the electronic and structural aspects of 3-tert-butyl-4-methoxyphenol (TBMP). Fourier-transform Infrared (FT-IR) and Fourier-transform Raman (FT-Raman) spectra of TBMP was recorded in the region 4000-400 cm(-1) and 3500-100 cm(-1), respectively. The molecular structures, vibrational wavenumbers, infrared intensities and Raman activities were calculated using DFT (B3LYP and LSDA) methods using 6-311++G (d,p) basis set. The most stable conformer of TBMP was identified from the computational results. The assignments of vibrational spectra have been carried out with the help of normal co-ordinate analysis (NCA) following the scaled quantum mechanical force field (SQMFF) methodology. The first order hyperpolarizability (β0) and related properties (β, α0 and Δα) of TBMP have been discussed. The stability and charge delocalization of the molecule was studied by Natural Bond Orbital (NBO) analysis. UV-Visible spectrum and effects of solvents have been discussed and the electronic properties such as HOMO and LUMO energies were determined by time-dependent TD-DFT approach with B3LYP/6-311++G (d,p) level of theory. The molecule orbital contributions are studied by density of energy states (DOSs). The reactivity sites are identified by mapping the electron density into electrostatic potential surface (MEP). Mulliken analysis of atomic charges is also calculated. The thermodynamic properties at different temperatures were calculated, revealing the correlations between standard heat capacities, standard entropy and standard enthalpy changes with temperatures. Global hardness, global softness, global electrophilicity and ionization potential of the title compound are determined. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Synthesis, X-ray diffraction method, spectroscopic characterization (FT-IR, 1H and 13C NMR), antimicrobial activity, Hirshfeld surface analysis and DFT computations of novel sulfonamide derivatives

    Science.gov (United States)

    Demircioğlu, Zeynep; Özdemir, Fethi Ahmet; Dayan, Osman; Şerbetçi, Zafer; Özdemir, Namık

    2018-06-01

    Synthesized compounds of N-(2-aminophenyl)benzenesulfonamide 1 and (Z)-N-(2-((2-nitrobenzylidene)amino)phenyl)benzenesulfonamide 2 were characterized by antimicrobial activity, FT-IR, 1H and 13C NMR. Two new Schiff base ligands containing aromatic sulfonamide fragment of (Z)-N-(2-((3-nitrobenzylidene)amino)phenyl)benzenesulfonamide 3 and (Z)-N-(2-((4-nitrobenzylidene)amino)phenyl)benzenesulfonamide 4 were synthesized and investigated by spectroscopic techniques including 1H and 13C NMR, FT-IR, single crystal X-ray diffraction, Hirshfeld surface, theoretical method analyses and by antimicrobial activity. The molecular geometry obtained from the X-ray structure determination was optimized Density Functional Theory (DFT/B3LYP) method with the 6-311++G(d,p) basis set in ground state. From the optimized geometry of the molecules of 3 and 4, the geometric parameters, vibrational wavenumbers and chemical shifts were computed. The optimized geometry results, which were well represented the X-ray data, were shown that the chosen of DFT/B3LYP 6-311G++(d,p) was a successful choice. After a successful optimization, frontier molecular orbitals, chemical activity, non-linear optical properties (NLO), molecular electrostatic mep (MEP), Mulliken population method, natural population analysis (NPA) and natural bond orbital analysis (NBO), which cannot be obtained experimentally, were calculated and investigated.

  5. Spectroscopic investigations (FT-IR & FT-Raman) and molecular docking analysis of 6-[1-methyl-4-nitro-1H-imidazol-5-yl) sulfonyl]-7H-purine

    Science.gov (United States)

    Prasath, M.; Govindammal, M.; Sathya, B.

    2017-10-01

    The Azathioprine is used as anticancer agent. Azathioprine is chemically called 6-[1-methyl-4-nitro-1H-imidazol-5-yl) sulfonyl]-7H-purine (6M4N5P). The vibrational analysis of the 6M4N5P compound was carried out by using FT-IR and FT-Raman spectroscopic techniques and compared with aspects. The optimized geometry, frequency and intensity of the vibrational bands of 6M4N5P were obtained from the HF and DFT methods with 6-31G (d,p) basis set. The harmonic vibrational frequencies were calculated and the scaled values have been compared with experimental FT-IR and FT-Raman spectra. The calculated Highest Occupied Molecular Orbital (HOMO) and Lowest Unoccupied Molecular Orbital (LUMO) energies show that charge transfer occur within the molecule. MEP (Molecular Electrostatic Potential) is very useful in the investigation of the charge distributions and molecular structure. The molecule orbital contributions were determined by using the total density of states (TDOS). A molecular docking analysis has been carried out to understand the conformational change and electrostatic properties of 6M4N5P in the active site of Rac1-Receptor.

  6. A preliminary high-pressure thermogravimetric study of combustion reactivity of a Collie coal char

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Yii Leng; Zhang, Zhezi; Zhu, Mingming; Zhang, Dongke [Western Australia Univ., Crawley, WA (Australia). Centre for Energy (M473); Luan, Chao [Western Australia Univ., Crawley, WA (Australia). Centre for Energy (M473); Tsinghua Univ., Beijing (China). Inst. of Thermal Engineering; You, Changfu [Tsinghua Univ., Beijing (China). Inst. of Thermal Engineering

    2013-07-01

    The effect of pressure(up to 20 bar)on the reactivity of a char(150-160 {mu}m) produced from Western Australian Collie coal has been studied using a high-pressure thermogravimetric analyser (HP TGA). The pressure demonstrated a positive effect in enhancing char combustion reactivities.Kinetic parameters have been determined from the experimental data.The apparent reaction order was found to be approximately 0.7 and the apparent activation energies were 91.0 kJ/mol at atmospheric pressure and 1.5 kJ/mol at an elevated pressure(10 bar),indicating a shift in the control regimes of the reaction at elevated pressures.The lumped effect of the sample size, bulk diffusion,interparticle and intraparticle diffusion at the elevated pressures played an important role in reducing the mass transfer during the HP-TGA experimentation.Thus the activation energy calculated at elevated pressures may not represent the intrinsic activation energy of the char particles but the apparent values of the bulk of the samples.

  7. Vaporization enthalpies of imidazolium based ionic liquids. A thermogravimetric study of the alkyl chain length dependence

    International Nuclear Information System (INIS)

    Verevkin, Sergey P.; Zaitsau, Dzmitry H.; Emel’yanenko, Vladimir N.; Ralys, Ricardas V.; Yermalayeu, Andrei V.; Schick, Christoph

    2012-01-01

    Highlights: ► Enthalpies of vaporization of ionic liquids were measured with thermogravimetry. ► We studied 1-alkyl-3-methyl-imidazolium bis(trifluoromethanesulfonyl)imide. ► The linear alkyl chain length was 4, 6, 8, 10, 12, 14, 16, and 18 C-atoms. ► A linear dependence on the chain length of the alkyl-imidazolium cation was found. - Abstract: Vaporization enthalpies for a series of ten ionic liquids (ILs) 1-alkyl-3-methyl-imidazolium bis(trifluoromethanesulfonyl)imide [C n mim][NTf 2 ], with the alkyl chain length n = 4, 6, 8, 10, 12, 14, 16, and 18 were determined using the thermogravimetric method. An internally consistent set of experimental data and vaporization enthalpies at 540 K was obtained. Vaporization enthalpies at 540 K have shown a linear dependence on the chain length of the alkyl-imidazolium cation in agreement with the experimental results measured previously with a quartz crystal microbalance. Ambiguity of Δ l g C pm o -values required for the extrapolation of experimental vaporization enthalpies to the reference temperature 298 K has been discussed.

  8. Thermogravimetric studies of high temperature reactions between potassium salts and chromium

    International Nuclear Information System (INIS)

    Lehmusto, J.; Lindberg, D.; Yrjas, P.; Skrifvars, B.-J.; Hupa, M.

    2012-01-01

    Highlights: ► K 2 CO 3 reacted with Cr 2 O 3 forming K 2 CrO 4 . ► Presence of chlorine did not alone explain the initiation of accelerated oxidation. ► More light was shed to the role of chromates in accelerated oxidation. ► Accelerated oxidation of chromia protected steels occurs in two consecutive stages. ► Both potassium and chloride are required, so that both stages of reaction occur. - Abstract: This study compares the high temperature reactions of potassium chloride (KCl) and potassium carbonate (K 2 CO 3 ), two salts found in fly ashes formed in biomass combustion, with both pure metallic chromium (Cr) and chromium oxide (Cr 2 O 3 ). The reactions were investigated with thermogravimetric measurements and the results discussed based on thermodynamic calculations. In simple terms: potassium chloride reacted with chromium forming potassium chromate (K 2 CrO 4 ) and chromium oxide. Potassium chloride did not react with chromium oxide. Potassium carbonate reacted with chromium oxide, but not with chromium. The presence of potassium is sufficient to initiate accelerated oxidation, but chloride is needed to sustain it.

  9. Relativistic band-structure calculations for CeTIn sub 5 (T=Ir and Co) and analysis of the energy bands by using tight-binding method

    CERN Document Server

    Maehira, T; Ueda, K; Hasegawa, A

    2003-01-01

    In order to investigate electronic properties of recently discovered heavy fermion superconductors CeTIn sub 5 (T=Ir and Co), we employ the relativistic linear augmented-plane-wave (RLAPW) method to clarify the energy band structures and Fermi surfaces of those materials. The obtained energy bands mainly due to the large hybridization between Ce 4 f and In 5 p states well reproduce the Fermi surfaces consistent with the de Haas-van Alphen experimental results. However, when we attempt to understand magnetism and superconductively in CeTIn sub 5 from the microscopic viewpoint, the energy bands obtained in the RLAPW method are too complicated to analyze the system by further including electron correlations. Thus, it is necessary to prepare a more simplified model, keeping correctly the essential characters of the energy bands obtained in the band-structure calculation. For the purpose, we construct a tight-binding model for CeTIn sub 5 by including f-f and p-p hoppings as well as f-p hybridization, which are ex...

  10. Hydrogel-Embedded Model Photocatalytic System Investigated by Raman and IR Spectroscopy Assisted by Density Functional Theory Calculations and Two-Dimensional Correlation Analysis.

    Science.gov (United States)

    Geitner, Robert; Götz, Stefan; Stach, Robert; Siegmann, Michael; Krebs, Patrick; Zechel, Stefan; Schreyer, Kristin; Winter, Andreas; Hager, Martin D; Schubert, Ulrich S; Gräfe, Stefanie; Dietzek, Benjamin; Mizaikoff, Boris; Schmitt, Michael; Popp, Jürgen

    2018-03-15

    The presented study reports the synthesis and the vibrational spectroscopic characterization of different matrix-embedded model photocatalysts. The goal of the study is to investigate the interaction of a polymer matrix with photosensitizing dyes and metal complexes for potential future photocatalytic applications. The synthesis focuses on a new rhodamine B derivate and a Pt(II) terpyridine complex, which both contain a polymerizable methacrylate moiety and an acid labile acylhydrazone group. The methacrylate moieties are afterward utilized to synthesize functional model hydrogels mainly consisting of poly(ethylene glycol) methacrylate units. The pH-dependent and temperature-dependent behavior of the hydrogels is investigated by means of Raman and IR spectroscopy assisted by density functional theory calculations and two-dimensional correlation spectroscopy. The spectroscopic results reveal that the Pt(II) terpyridine complex can be released from the polymer matrix by cleaving the C═N bond in an acid environment. The same behavior could not be observed in the case of the rhodamine B dye although it features a comparable C═N bond. The temperature-dependent study shows that the water evaporation has a significant influence neither on the molecular structure of the hydrogel nor on the model photocatalytic moieties.

  11. Spectroscopic [FT-IR and FT-Raman] and theoretical [UV-Visible and NMR] analysis on α-Methylstyrene by DFT calculations

    Science.gov (United States)

    Karthikeyan, N.; Joseph Prince, J.; Ramalingam, S.; Periandy, S.

    2015-05-01

    In the present research work, the FT-IR, FT-Raman and 13C and 1H NMR spectra of the α-Methylstyrene were recorded. The observed fundamental frequencies in finger print as well as functional group regions were assigned according to their uniqueness region. The Gaussian computational calculations are carried out by HF and DFT (B3LYP and B3PW91) methods with 6-31++G(d,p) and 6-311++G(d,p) basis sets and the corresponding results were tabulated. The impact of the presence of vinyl group in phenyl structure of the compound is investigated. The modified vibrational pattern of the molecule associated vinyl group was analyzed. Moreover, 13C NMR and 1H NMR were calculated by using the gauge independent atomic orbital (GIAO) method with B3LYP methods and the 6-311++G(d,p) basis set and their spectra were simulated and the chemical shifts linked to TMS were compared. A study on the electronic and optical properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies were carried out. The kubo gap of the present compound was calculated related to HOMO and LUMO energies which confirm the occurring of charge transformation between the base and ligand. Besides frontier molecular orbitals (FMO), molecular electrostatic potential (MEP) was performed. The NLO properties related to Polarizability and hyperpolarizability based on the finite-field approach were also discussed.

  12. Preparation and characterizations of SnO2 nanopowder and spectroscopic (FT-IR, FT-Raman, UV-Visible and NMR) analysis using HF and DFT calculations.

    Science.gov (United States)

    Ayeshamariam, A; Ramalingam, S; Bououdina, M; Jayachandran, M

    2014-01-24

    In this work, pure and singe phase SnO2 Nano powder is successfully prepared by simple sol-gel combustion route. The photo luminescence and XRD measurements are made and compared the geometrical parameters with calculated values. The FT-IR and FT-Raman spectra are recorded and the fundamental frequencies are assigned. The optimized parameters and the frequencies are calculated using HF and DFT (LSDA, B3LYP and B3PW91) theory in bulk phase of SnO2 and are compared with its Nano phase. The vibrational frequency pattern in nano phase gets realigned and the frequencies are shifted up to higher region of spectra when compared with bulk phase. The NMR and UV-Visible spectra are simulated and analyzed. Transmittance studies showed that the HOMO-LUMO band gap (Kubo gap) is reduced from 3.47 eV to 3.04 eV while it is heated up to 800°C. The Photoluminescence spectra of SnO2 powder showed a peak shift towards lower energy side with the change of Kubo gap from 3.73 eV to 3.229 eV for as-prepared and heated up to 800°C. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

  13. The spectroscopic (FT-IR, FT-Raman, UV and NMR) first order hyperpolarizability and HOMO-LUMO analysis of dansyl chloride

    Science.gov (United States)

    Karabacak, M.; Cinar, M.; Kurt, M.; Poiyamozhi, A.; Sundaraganesan, N.

    2014-01-01

    The solid phase FT-IR and FT-Raman spectra of dansyl chloride (DC) have been recorded in the regions 400-4000 and 50-4000 cm-1, respectively. The spectra have been interpreted in terms of fundamentals modes, combination and overtone bands. The structure of the molecule has been optimized and the structural characteristics have been determined by density functional theory (B3LYP) method with 6-311++G(d,p) as basis set. The vibrational frequencies were calculated for most stable conformer and were compared with the experimental frequencies, which yield good agreement between observed and calculated frequencies. The infrared and Raman spectra have also been predicted from the calculated intensities. 1H and 13C NMR spectra were recorded and 1H and 13C nuclear magnetic resonance chemical shifts of the molecule were calculated using the gauge independent atomic orbital (GIAO) method. UV-Visible spectrum of the compound was recorded in the region 200-600 nm and the electronic properties HOMO and LUMO energies were measured by time-dependent TD-DFT approach. Nonlinear optical and thermodynamic properties were interpreted. All the calculated results were compared with the available experimental data of the title molecule.

  14. Analysis of 19th century ceramic fragments excavated from Pirenópolis (Goiás, Brazil) using FT-IR, Raman, XRF and SEM

    Science.gov (United States)

    Freitas, Renato P.; Coelho, Filipe A.; Felix, Valter S.; Pereira, Marcelo O.; de Souza, Marcos André Torres; Anjos, Marcelino J.

    2018-03-01

    This study used Raman, FT-IR and XRF spectroscopy and SEM to analyze ceramic fragments dating from the 19th century, excavated from an old farm in the municipality of Pirenópolis, Goiás, Brazil. The results show that the samples were produced in an open oven at a firing temperature below 500 °C, using raw materials including kaolinite, hematite, magnetite, quartz, microcline, albite, anhydrite, calcite, illite, orthoclase and MnO2. Although the analyses showed similarities in the manufacturing process and the presence of many minerals was common in all samples, multivariate statistical methods (PCA) allowed a more detailed assessment of similarities and differences in the mineral composition of the samples. The results of the PCA showed that the samples excavated in one of the slave quarters (senzalas) group with those excavated at the farmhouse, where the landowner lived, which indicates a paternalistic attitude towards captives, including the sharing of ceramic materials of everyday use.

  15. Quantum computational studies, spectroscopic (FT-IR, FT-Raman and UV-Vis) profiling, natural hybrid orbital and molecular docking analysis on 2,4 Dibromoaniline

    Science.gov (United States)

    Abraham, Christina Susan; Prasana, Johanan Christian; Muthu, S.; Rizwana B, Fathima; Raja, M.

    2018-05-01

    The research exploration will comprise of investigating the molecular structure, vibrational assignments, bonding and anti-bonding nature, nonlinear optical, electronic and thermodynamic nature of the molecule. The research is conducted at two levels: First level employs the spectroscopic techniques - FT-IR, FT-Raman and UV-Vis characterizing techniques; at second level the data attained experimentally is analyzed through theoretical methods using and Density Function Theories which involves the basic principle of solving the Schrodinger equation for many body systems. A comparison is drawn between the two levels and discussed. The probability of the title molecule being bio-active theoretically proved by the electrophilicity index leads to further property analyzes of the molecule. The target molecule is found to fit well with Centromere associated protein inhibitor using molecular docking techniques. Higher basis set 6-311++G(d,p) is used to attain results more concurrent to the experimental data. The results of the organic amine 2, 4 Dibromoaniline is analyzed and discussed.

  16. Application of experimental design in examination of the dissolution rate of carbamazepine from formulations: Characterization of the optimal formulation by DSC, TGA, FT-IR and PXRD analysis

    Directory of Open Access Journals (Sweden)

    Krstić Marko

    2015-01-01

    Full Text Available Poor solubility is one of the key reasons for the poor bioavailability of these drugs. This paper displays a formulation of a solid surfactant system with carbamazepine, in order to increase its dissolution rate. Solid state surfactant systems are formed by application of fractal experimental design. Poloxamer 237 and Poloxamer 338 were used as surfactants and Brij® 35 was used as the co-surfactant. The ratios of the excipients and carbamazepine were varied and their effects on the dissolution rate of carbamazepine were examined. Moreover, the effects of the addition of natural (diatomite and a synthetic adsorbent carrier (Neusiline UFL2 on the dissolution rate of carbamazepine were also tested. The prepared surfactant systems were characterized and the influence of the excipients on possible changes of the polymorphous form of carbamazepine examined by application of analytical techniques (DSC, TGA, FT-IR, PXRD. It was determined that an appropriate selection of the excipient type and ratio could provide a significant increase in the carbamazepine dissolution rate. By application of analytical techniques, it was found that that the employed excipients induce a transition of carbamazepine into the amorphous form and that the selected sample was stable for three months, when kept under ambient conditions. [Projekat Ministarstva nauke Republike Srbije, br. TR34007

  17. Solubility and IR studies of gamma-irradiated arabinoxylan

    International Nuclear Information System (INIS)

    Ebringerova, A.; Kacurakova, M.; Hromadkova, Z.; Pruzinec, J.

    1989-01-01

    The structural and solubility changes of a water-insoluble arabinoxylan with a low degree of branching was studied after γ-irradiation by IR spectroscopy and chemical analysis of the polysaccharide and its polymeric fractions. New functional groups like hydroperoxidic, carbonylic and endiolic ones were found after irradiation. The IR spectra shows that the structural changes involved by radiolytic treatment are reflected in the shape of the IR spectra of both polymeric fractions. The ratio of absorbance of the peaks at 1725 and 2920 cm -1 increased with radiation dose. (author) 17 refs.; 2 figs.; 2 tabs

  18. TG-FTIR analysis of biomass pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Bassilakis, R.; Carangelo, R.M.; Wojtowicz, M.A. [Advanced Fuel Research Inc., Hartford, CT (United States)

    2001-10-09

    A great need exists for comprehensive biomass-pyrolysis models that could predict yields and evolution patterns of selected volatile products as a function of feedstock characteristics and process conditions. A thermogravimetric analyzer coupled with Fourier transform infrared analysis of evolving products (TG-FTIR) can provide useful input to such models in the form of kinetic information obtained under low heating rate conditions. In this work, robust TG-FTIR quantification routes were developed for infrared analysis of volatile products relevant to biomass pyrolysis. The analysis was applied to wheat straw, three types of tobacco (Burley, Oriental, and Bright) and three biomass model compounds (xylan, chlorogenic acid, and D-glucose). Product yields were compared with literature data, and species potentially quantifiable by FT-IR are reviewed. Product-evolution patterns are reported for all seven biomass samples. 41 refs., 7 figs., 2 tabs.

  19. PEP-II IR-2 Alignment

    International Nuclear Information System (INIS)

    Seryi, A

    2004-01-01

    This paper describes the first results and preliminary analysis obtained with several alignment monitoring systems recently installed in the PEP-II interaction region. The hydrostatic level system, stretched wire system, and laser tracker have been installed in addition to the existing tiltmeters and LVDT sensors. These systems detected motion of the left raft, which correlated primarily with the low energy ring (LER) current. The motion is of the order of 120 micrometers. The cause was identified as synchrotron radiation heating the beampipe, causing its expansion which then results in its deformation and offset of the IR quadrupoles. We also discuss further plans on measurements, analysis and means to counteract this motion

  20. Determinação da espessura da camada polimérica de fases estacionárias imobilizadas para cromatografia líquida de alta eficiência por termogravimetria Determination of polymeric layer thickness on immobilized stationary phases for high-performance liquid chromatography using thermogravimetric analyses

    Directory of Open Access Journals (Sweden)

    Anizio M. Faria

    2008-01-01

    Full Text Available This paper presents a simple and practical thermogravimetric method for determining the layer thickness of immobilized polymer stationary phases used in reversed-phase high-performance liquid chromatography. In this method, the weight loss of different polysiloxanes immobilized onto chromatographic supports, determined over the temperature range 150-650 ºC, demonstrated excellent agreement with the sum of carbon and hydrogen content obtained by elemental analysis. The results presented here suggest that the thermogravimetric procedure is an accurate and precise method to determine the polymeric material content on polymer-coated stationary phases.

  1. Biological activities of Allium sativum and Zingiber officinale extracts on clinically important bacterial pathogens, their phytochemical and FT-IR spectroscopic analysis.

    Science.gov (United States)

    Awan, Uzma Azeem; Ali, Shaukat; Shahnawaz, Amna Mir; Shafique, Irsa; Zafar, Atiya; Khan, Muhammad Abdul Rauf; Ghous, Tahseen; Saleem, Azhar; Andleeb, Saiqa

    2017-05-01

    The spread of bacterial infectious diseases is a major public threat. Herbs and spices have offered an excellent, important and useful source of antimicrobial agents against many pathological infections. In the current study, the antimicrobial potency of fresh, naturally and commercial dried Allium sativum and Zingiber officinale extracts had been investigated against seven local clinical bacterial isolates such as Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, Staphylococcus aureus, Streptococcus pyogenes, Staphylococcus epidermidis, and Serratia marcesnces by the agar disc diffusion method. All tested pathogens except P. aeruginosa and E. coli were most susceptible to ethanolic and methanolic extracts of A. sativum. Similarly, chloroform and diethyl ether extracts of Z. officinale showed a greater zone of inhibition of tested pathogens except for P. aeruginosa and E. coli. We found that all extracts of A. sativum and Z. officinale have a strong antibacterial effect compared to recommended standard antibiotics through activity index. All results were evaluated statistically and a significant difference was recorded at Psativum and Z. officinale proposed the presence of various phytochemicals such as tannins, phenols, alkaloids, steroids and saponins. Retention factor of diverse phytochemicals provides a valuable clue regarding their polarity and the selection of solvents for separation of phytochemicals. Significant inhibition of S. aureus was also observed through TLC-Bioautography. FT-IR Spectrometry was also performed to characterize both natural and commercial extracts of A. sativum and Z. officinale to evaluate bioactive compounds. These findings provide new insights to use A. sativum and Z. officinale as potential plant sources for controlling pathogenic bacteria and potentially considered as cost-effective in the management of diseases and to the threat of drug resistance phenomenon.

  2. Spectroscopic [FT-IR and FT-Raman] and theoretical [UV-Visible and NMR] analysis on α-Methylstyrene by DFT calculations.

    Science.gov (United States)

    Karthikeyan, N; Joseph Prince, J; Ramalingam, S; Periandy, S

    2015-05-15

    In the present research work, the FT-IR, FT-Raman and (13)C and (1)H NMR spectra of the α-Methylstyrene were recorded. The observed fundamental frequencies in finger print as well as functional group regions were assigned according to their uniqueness region. The Gaussian computational calculations are carried out by HF and DFT (B3LYP and B3PW91) methods with 6-31++G(d,p) and 6-311++G(d,p) basis sets and the corresponding results were tabulated. The impact of the presence of vinyl group in phenyl structure of the compound is investigated. The modified vibrational pattern of the molecule associated vinyl group was analyzed. Moreover, (13)C NMR and (1)H NMR were calculated by using the gauge independent atomic orbital (GIAO) method with B3LYP methods and the 6-311++G(d,p) basis set and their spectra were simulated and the chemical shifts linked to TMS were compared. A study on the electronic and optical properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies were carried out. The kubo gap of the present compound was calculated related to HOMO and LUMO energies which confirm the occurring of charge transformation between the base and ligand. Besides frontier molecular orbitals (FMO), molecular electrostatic potential (MEP) was performed. The NLO properties related to Polarizability and hyperpolarizability based on the finite-field approach were also discussed. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

  3. Thermogravimetric measurement of hydrogen storage in carbon-based materials: promise and pitfalls

    International Nuclear Information System (INIS)

    Pinkerton, F.E.; Wicke, B.G.; Olk, C.H.; Tibbetts, G.G.; Meisner, G.P.; Meyer, M.S.; Herbst, J.F.

    2000-01-01

    We have used a thermogravimetric analyzer (TGA) to measure the hydrogen absorption capacity of a variety of carbon-based storage materials, including Li- and K-intercalated graphite and Li-doped multi-wall nanotubes. The TGA uses weight gain/loss as a function of time and temperature to monitor hydrogen absorption/desorption in flowing hydrogen gas. Creating and maintaining a contaminant-free atmosphere is critical to the accurate TGA measurement of hydrogen absorption in carbon-based materials; even low concentrations of impurity gases such as O 2 or H 2 O are sufficient to masquerade as hydrogen absorption. We will discuss examples of this effect relevant to recent reports of hydrogen storage appearing in the literature. The precautions required are non-trivial. In our TGA, for instance, about 16% of the original atmosphere remains after a two-hour purge; at least 15 hours is required to fully purge the apparatus. Furthermore, we cover the TGA with a protective atmosphere enclosure during sample loading to minimize the introduction of impurity gases. With these precautions it is possible to unambiguously measure hydrogen storage. For example, we have determined the hydrogen absorption capacity of our K-intercalated graphite samples to be 1.3 wt% total hydrogen absorption above 50 o C, of which 0.2 wt% can be reproducibly recovered with temperature cycling. With due care, TGA measurements provide complementary information to that obtained from standard pressure techniques for measuring hydrogen sorption, which rely on measuring the loss of gas pressure in a known volume. Taken together, TGA and pressure measurements provide a powerful combination for determining verifiable hydrogen storage capacity. (author)

  4. Thermogravimetric pyrolysis kinetics of bamboo waste via Asymmetric Double Sigmoidal (Asym2sig) function deconvolution.

    Science.gov (United States)

    Chen, Chuihan; Miao, Wei; Zhou, Cheng; Wu, Hongjuan

    2017-02-01

    Thermogravimetric kinetic of bamboo waste (BW) pyrolysis has been studied using Asymmetric Double Sigmoidal (Asym2sig) function deconvolution. Through deconvolution, BW pyrolytic profiles could be separated into three reactions well, each of which corresponded to pseudo hemicelluloses (P-HC), pseudo cellulose (P-CL), and pseudo lignin (P-LG) decomposition. Based on Friedman method, apparent activation energy of P-HC, P-CL, P-LG was found to be 175.6kJ/mol, 199.7kJ/mol, and 158.4kJ/mol, respectively. Energy compensation effects (lnk 0, z vs. E z ) of pseudo components were in well linearity, from which pre-exponential factors (k 0 ) were determined as 6.22E+11s -1 (P-HC), 4.50E+14s -1 (P-CL) and 1.3E+10s -1 (P-LG). Integral master-plots results showed pyrolytic mechanism of P-HC, P-CL, and P-LG was reaction order of f(α)=(1-α) 2 , f(α)=1-α and f(α)=(1-α) n (n=6-8), respectively. Mechanism of P-HC and P-CL could be further reconstructed to n-th order Avrami-Erofeyev model of f(α)=0.62(1-α)[-ln(1-α)] -0.61 (n=0.62) and f(α)=1.08(1-α)[-ln(1-α)] 0.074 (n=1.08). Two-steps reaction was more suitable for P-LG pyrolysis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Broadly tunable picosecond ir source

    International Nuclear Information System (INIS)

    Campillo, A.J.; Hyer, R.C.; Shapiro, S.L.

    1979-01-01

    A completely grating tuned (1.9 to 2.4 μm) picosecond traveling wave IR generator capable of controlled spectral bandwidth operation down to the Fourier Transform limit is reported. Subsequent down conversion in CdSe extends tuning to 10 to 20 μm

  6. Ion beam synthesis of IrSi3 by implantation of 2 MeV Ir ions

    International Nuclear Information System (INIS)

    Sjoreen, T.P.; Chisholm, M.F.; Hinneberg, H.J.

    1992-11-01

    Formation of a buried IrSi 3 layer in (111) oriented Si by ion implantation and annealing has been studied at an implantation energy of 2 MeV for substrate temperatures of 450--550C. Rutherford backscattering (RBS), ion channeling and cross-sectional transmission electron microscopy showed that a buried epitaxial IrSi 3 layer is produced at 550C by implanting ≥ 3.4 x 10 17 Ir/cm 2 and subsequently annealing for 1 h at 1000C plus 5 h at 1100C. At a dose of 3.4 x 10 17 Ir/cm 2 , the thickness of the layer varied between 120 and 190 nm and many large IrSi 3 precipitates were present above and below the film. Increasing the dose to 4.4 x 10 17 Ir/cm 2 improved the layer uniformity at the expense of increased lattice damage in the overlying Si. RBS analysis of layer formation as a function of substrate temperature revealed the competition between the mechanisms for optimizing surface crystallinity vs. IrSi 3 layer formation. Little apparent substrate temperature dependence was evident in the as-implanted state but after annealing the crystallinity of the top Si layer was observed to deteriorate with increasing substrate temperature while the precipitate coarsening and coalescence improved

  7. Thermogravimetric control of intermediate compounds in uranium metallurgy; Control termogravimetrico de productos intermedios de la metalurgia del uranio

    Energy Technology Data Exchange (ETDEWEB)

    Gasco Sanchez, L; Fernandez Cellini, R

    1959-07-01

    The thermal decomposition of some intermediate compounds in the metallurgy of the uranium as uranium peroxide, ammonium uranate, uranium and ammonium penta-fluoride, uranium tetrafluoride and uranous oxide has been study by means of the Chevenard's thermo balance. Some data on pyrolysis of synthetic mixtures of intermediate compounds which may occasionally appear during the industrial process, are given. Thermogravimetric methods of control are suggested, usable in interesting products in the uranium metallurgy. (Author) 20 refs.

  8. Thermogravimetric control of intermediate compounds in uranium metallurgy; Control termogravimetrico de productos intermedios de la metalurgia del uranio

    Energy Technology Data Exchange (ETDEWEB)

    Gasco Sanchez, L.; Fernandez Cellini, R.

    1959-07-01

    The thermal decomposition of some intermediate compounds in the metallurgy of the uranium as uranium peroxide, ammonium uranate, uranium and ammonium penta-fluoride, uranium tetrafluoride and uranous oxide has been study by means of the Chevenard's thermo balance. Some data on pyrolysis of synthetic mixtures of intermediate compounds which may occasionally appear during the industrial process, are given. Thermogravimetric methods of control are suggested, usable in interesting products in the uranium metallurgy. (Author) 20 refs.

  9. Spectroscopic investigation (FT-IR and FT-Raman), vibrational assignments, HOMO-LUMO analysis and molecular docking study of 1-hydroxy-4,5,8-tris(4-methoxyphenyl) anthraquinone

    Science.gov (United States)

    Renjith, R.; Sheena Mary, Y.; Tresa Varghese, Hema; Yohannan Panicker, C.; Thiemann, Thies; Shereef, Anas; Al-Saadi, Abdulaziz A.

    2015-12-01

    FT-IR and FT-Raman spectra of 1-hydroxy-4,5,8-tris(4-methoxyphenyl)anthraquinone were recorded and analyzed. The vibrational wavenumbers were computed using DFT quantum chemical calculations. The data obtained from wavenumber calculations were used to assign the vibrational bands obtained experimentally. A detailed molecular picture of the title compound and its interactions were obtained from NBO analysis. From the MEP plot it is clear that the negative electrostatic potential regions are mainly localized over carbonyl group. There is some evidence of a region of negative electrostatic potential due to π-electron density of the benzo groups. Molecular docking study shows that methoxy groups attached to the phenyl rings and hydroxyl group are crucial for binding and the title compound might exhibit inhibitory activity against PI3K and may act as an anti-neoplastic agent.

  10. Alkoholio ir tabako pasiūlos ir paklausos teisinio reguliavimo raida Lietuvos Respublikoje: problemos ir sprendimai

    OpenAIRE

    Mockevičius, Arminas

    2014-01-01

    Viešosios teisės magistro studijų programos studento Armino Mockevičiaus buvo parašytas magistro baigiamasis darbas „Alkoholio ir tabako pasiūlos ir paklausos teisinio reguliavimo raida Lietuvos Respublikoje: problemos ir sprendimai“. Šis darbas parašytas Vilniuje, 2014 metais, Mykolo Romerio universiteto Teisės fakulteto Konstitucinės ir administracinės teisės institute, vadovaujant dr. Gintautui Vilkeliui, apimtis 98 p. Darbo tikslas yra atskleisti alkoholio ir tabako pasiūlos ir paklau...

  11. A new Density Functional Theory (DFT) based method for supporting the assignment of vibrational signatures of mannan and cellulose—Analysis of palm kernel cake hydrolysis by ATR-FT-IR spectroscopy as a case study

    DEFF Research Database (Denmark)

    Barsberg, Søren Talbro; Sanadi, Anand Ramesh; Jørgensen, Henning

    2011-01-01

    Attenuated Total Reflectance (ATR) FT-IR spectroscopy gives in situ information on molecular concentration, organization and interactions in plant cell walls. We demonstrate its potential for further developments by a case study which combines ATR-FT-IR spectroscopy with a recently published DFT...... a decreasing degree of polymerization to be a plausible cause, although others may interfere. Keywords: Cellulose; Mannan; FT-IR; DFT; Molecular modelling; Palm kernel...

  12. IR fixed points in SU(3 gauge theories

    Directory of Open Access Journals (Sweden)

    K.-I. Ishikawa

    2015-09-01

    Full Text Available We propose a novel RG method to specify the location of the IR fixed point in lattice gauge theories and apply it to the SU(3 gauge theories with Nf fundamental fermions. It is based on the scaling behavior of the propagator through the RG analysis with a finite IR cutoff, which we cannot remove in the conformal field theories in sharp contrast to the confining theories. The method also enables us to estimate the anomalous mass dimension in the continuum limit at the IR fixed point. We perform the program for Nf=16,12,8 and Nf=7 and indeed identify the location of the IR fixed points in all cases.

  13. Adjoint Sensitivity Analysis of Radiative Transfer Equation: Temperature and Gas Mixing Ratio Weighting Functions for Remote Sensing of Scattering Atmospheres in Thermal IR

    Science.gov (United States)

    Ustinov, E.

    1999-01-01

    Sensitivity analysis based on using of the adjoint equation of radiative transfer is applied to the case of atmospheric remote sensing in the thermal spectral region with non-negligeable atmospheric scattering.

  14. Oferta ir akceptas vartojimo sutartyse

    OpenAIRE

    Ežerskytė, Ramunė

    2011-01-01

    Sutarčiai sudaryti paprastai reikia, kad viena šalis pasiūlytų sudaryti sutartį (oferta), o kita šalis sutiktų su pasiūlymu (akceptas). Sutarčių įvairovėje išskiriamos vartojimo sutartys, kurios dėl silpnesnės šalies apsaugos principo įgyvendinimo pasižymi tam tikrais ypatumais. Vartojimo sutarčių sudarymas pateikiant ofertą ir akceptą yra šio magistro baigiamojo darbo objektas. Magistro baigiamąjį darbą sudaro trys dalys. Pirmojoje darbo dalyje analizuojama vartojimo sutarties sąvoka ir spec...

  15. Data in support of FSH induction of IRS-2 in human granulosa cells: Mapping the transcription factor binding sites in human IRS-2 promoter

    Directory of Open Access Journals (Sweden)

    Surleen Kaur

    2016-03-01

    Full Text Available Insulin receptor substrate-2 (IRS-2 plays critical role in the regulation of various metabolic processes by insulin and IGF-1. The defects in its expression and/or function are linked to diseases like polycystic ovary syndrome (PCOS, insulin resistance and cancer. To predict the transcription factors (TFs responsible for the regulation of human IRS-2 gene expression, the transcription factor binding sites (TFBS and the corresponding TFs were investigated by analysis of IRS-2 promoter sequence using MatInspector Genomatix software (Cartharius et al., 2005 [1]. The ibid data is part of author׳s publication (Anjali et al., 2015 [2] that explains Follicle stimulating hormone (FSH mediated IRS-2 promoter activation in human granulosa cells and its importance in the pathophysiology of PCOS. Further analysis was carried out for binary interactions of TF regulatory genes in IRS-2 network using Cytoscape software tool and R-code. In this manuscript, we describe the methodology used for the identification of TFBSs in human IRS-2 promoter region and provide details on experimental procedures, analysis method, validation of data and also the raw files. The purpose of this article is to provide the data on all TFBSs in the promoter region of human IRS-2 gene as it has the potential for prediction of the regulation of IRS-2 gene in normal or diseased cells from patients with metabolic disorders and cancer. Keywords: IRS-2, TFBS, FSH, SP1, ChIP

  16. Direct analysis of triterpenes from high-salt fermented cucumbers using infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI)

    Science.gov (United States)

    High-salt samples present a challenge to mass spectrometry (MS) analysis, particularly when electrospray ionization (ESI) is used, requiring extensive sample preparation steps such as desalting, extraction, and purification. In this study, infrared matrix-assisted laser desorption electrospray ioniz...

  17. Climate Prediction Center IR 4km Dataset

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — CPC IR 4km dataset was created from all available individual geostationary satellite data which have been merged to form nearly seamless global (60N-60S) IR...

  18. IR, UV-Vis, magnetic and thermal characterization of chelates of some catecholamines and 4-aminoantipyrine with Fe(III) and Cu(II)

    Science.gov (United States)

    Mohamed, Gehad G.; Zayed, M. A.; El-Dien, F. A. Nour; El-Nahas, Reham G.

    2004-07-01

    The dopamine derivatives participate in the regulation of wide variety of physiological functions in the human body and in medication life. Increase and/or decrease in the concentration of dopamine in human body reflect an indication for diseases such as Schizophrenia and/or Parkinson diseases. α-Methyldopa (α-MD) in tablets is used in medication of hypertension. The Fe(III) and Cu(II) chelates with coupled products of adrenaline hydrogen tartarate (AHT), levodopa (LD), α-MD and carbidopa (CD) with 4-aminoantipyrine (4-AAP) are prepared and characterized. Different physico-chemical methods like IR, magnetic and UV-Vis spectra are used to investigate the structure of these chelates. Fe(III) form 1:2 (M:catecholamines) chelates while Cu(II) form 1:1 chelates. Catecholamines behave as a bidentate mono- or dibasic ligands in binding to the metal ions. IR spectra show that the catecholamines are coordinated to the metal ions in a bidentate manner with O,O donor sites of the phenolic - OH. Magnetic moment measurements reveal the presence of Fe(III) chelates in octahedral geometry while the Cu(II) chelates are square planar. The thermal decomposition of Fe(III) and Cu(II) complexes is studied using thermogravimetric (TGA) and differential thermal analysis (DTA) techniques. The water molecules are removed in the first step followed immediately by decomposition of the ligand molecules. The activation thermodynamic parameters, such as, energy of activation, enthalpy, entropy and free energy change of the complexes are evaluated and the relative thermal stability of the complexes are discussed.

  19. Radioluminescence dating: the IR emission of feldspar

    International Nuclear Information System (INIS)

    Schilles, Thomas.; Habermann, Jan

    2000-01-01

    A new luminescence reader for radioluminescence (RL) measurements is presented. The system allows detection of RL emissions in the near infrared region (IR). Basic bleaching properties of the IR-RL emission of feldspars are investigated. Sunlight-bleaching experiments as a test for sensitivity changes are presented. IR-bleaching experiments were carried out to obtain information about the underlying physical processes of the IR-RL emission

  20. Morphological Changes of Limestone Sorbent Particles during Carbonation/Calcination Looping Cycles in a Thermogravimetric Analyzer (TGA) and Reactivation with Steam

    KAUST Repository

    Wu, Y.; Blamey, J.; Anthony, E. J.; Fennell, P. S.

    2010-01-01

    Carbonation and calcination looping cycles were carried out on four limestones in a thermogravimetric analyzer (TGA). The CO2 carrying capacity of a limestone particle decays very quickly in the first 10 cycles, reducing to about 20% of its original

  1. Thermogravimetric and calorimetric characteristics during co-pyrolysis of municipal solid waste components.

    Science.gov (United States)

    Ansah, Emmanuel; Wang, Lijun; Shahbazi, Abolghasem

    2016-10-01

    The thermogravimetric and calorimetric characteristics during pyrolysis of wood, paper, textile and polyethylene terephthalate (PET) plastic in municipal solid wastes (MSW), and co-pyrolysis of biomass-derived and plastic components with and without torrefaction were investigated. The active pyrolysis of the PET plastic occurred at a much higher temperature range between 360°C and 480°C than 220-380°C for the biomass derived components. The plastic pyrolyzed at a heating rate of 10°C/min had the highest maximum weight loss rate of 18.5wt%/min occurred at 420°C, followed by 10.8wt%/min at 340°C for both paper and textile, and 9.9wt%/min at 360°C for wood. At the end of the active pyrolysis stage, the final mass of paper, wood, textile and PET was 28.77%, 26.78%, 21.62% and 18.31%, respectively. During pyrolysis of individual MSW components at 500°C, the wood required the least amount of heat at 665.2J/g, compared to 2483.2J/g for textile, 2059.4J/g for paper and 2256.1J/g for PET plastic. The PET plastic had much higher activation energy of 181.86kJ/mol, compared to 41.47kJ/mol for wood, 50.01kJ/mol for paper and 36.65kJ/mol for textile during pyrolysis at a heating rate of 10°C/min. H2O and H2 peaks were observed on the MS curves for the pyrolysis of three biomass-derived materials but there was no obvious H2O and H2 peaks on the MS curves of PET plastic. There was a significant interaction between biomass and PET plastic during co-pyrolysis if the biomass fraction was dominant. The amount of heat required for the co-pyrolysis of the biomass and plastic mixture increased with the increase of plastic mass fraction in the mixture. Torrefaction at a proper temperature and time could improve the grindability of PET plastic. The increase of torrefaction temperature and time did not affect the temperature where the maximum pyrolytic rates occurred for both biomass and plastic but decreased the maximum pyrolysis rate of biomass and increased the maximum pyrolysis

  2. Composition dependence of phase transformation behavior and shape memory effect of Ti(Pt, Ir)

    International Nuclear Information System (INIS)

    Yamabe-Mitarai, Y.; Hara, T.; Kitashima, T.; Miura, S.; Hosoda, H.

    2013-01-01

    Highlights: ► The partial isothemal section at 1523 K was determined in Ti–Pt–Ir. ► The high-temperature shape memory effect of Ti(Pt, Ir) was investigated. ► The shape recovery ratio was 72% in Ti–10Pt–32Ir after deformation at 1123 K. ► Ir addition to TiPt is effective to improve shape memory effect of TiPt. -- Abstract: The phase transformation and high-temperature shape memory effect of Ti(Pt, Ir) were investigated. First, the Ti-rich phase boundary of Ti(Pt, Ir) was investigated by phase composition analysis by secondary electron microscopy (SEM) using an electron probe X-ray micro analyzer (EPMA), X-ray diffraction analysis and transmission electron microscopy (TEM). Then, the three alloys Ti–35Pt–10Ir, Ti–22Pt–22Ir, and Ti–10Pt–32Ir (at%) close to the phase boundary but in the single phase of Ti(Pt, Ir) were prepared by the arc melting method. The shape memory effect and crystal structure were investigated by compression loading–unloading tests and high-temperature X-ray diffraction analysis, respectively

  3. Determination of trace elements in the seeds of fruits using instrumental neutron activation analysis (INAA) in Arak, I.R. Iran

    International Nuclear Information System (INIS)

    Pourimani Reza; Meighani Elham; Fathivand Aliasghar

    2018-01-01

    In this study, four fruit's seed samples as Punica granatum L., Citrus medica var. limonum, Malus domestica L. and Citrus vulgaris Risso were prepared from Arak's markets. They were analyzed using instrumental neutron activation method (INAA). In this method, Tehran research reactor as a neutron source and relative INAA method has been used as the analysis method and to record gamma ray spectrum, the high purity germanium detector was used. Pomegranate seeds had the highest number of essential elements. Apple seeds and sour orange seeds contain the highest levels of Mg and K, Respectively. (author)

  4. Thermo spectral analysis (TSA) of living human skin by FT-IR -Development of a diagnostic method for the early detection of chronic diseases

    Science.gov (United States)

    Folberth, W.; Heim, G.

    1985-12-01

    A Fourier spectrometer was used in order to measure the spectral emissivity E(k) of human skin in the FIR region k=190-420 cm-1. Three studies on patient groups with defined chronic diseases have been performed: patients with untreated bronchial carcinoma, patients with rheumatic arthritis and patients with chronic renal insufficiency. In comparison with a symptomfree control group all patient groups show significant differences in E(k). As result of a discriminant analysis a separation of 95.7% between carcinoma patients and control persons is possible. The separation quotes between the other groups indicate that patients with malignant neoplasms can be discriminated from other chronically ill persons.

  5. Correlation of resistance and thermogravimetric measurements of the Er/sub 1/Ba/sub 2/Cu/sub 3/O/sub 9-δ/ superconductor to sample preparation techniques

    International Nuclear Information System (INIS)

    Lee, S.I.; Golben, J.P.; Song, Y.; Chen, X.D.; McMichael, R.D.; Gaines, J.R.

    1987-01-01

    The resistance dependence and thermogravimetric analysis (TGA) of Er/sub 1/Ba/sub 2/Cu/sub 3/O/sub 9-δ/ has been measured in the temperature range 27 C to 920 CV. The heat treatments and oxygen flow rates simulated actual sintering and annealing processes used in sample preparation. Evidence of a phase transition in Er/sub 1/Ba/sub 2/Cu/sub 3/O/sub 9-δ/ near 680 C is discussed, as well as the implications of the maximum oxygen uptake near 400 C. The impact of sample preparation procedures on sample features is also discussed

  6. Vibrational spectroscopy (FT-IR and Laser-Raman) investigation, and computational (M06-2X and B3LYP) analysis on the structure of 4-(3-fluorophenyl)-1-(propan-2-ylidene)-thiosemicarbazone.

    Science.gov (United States)

    Sert, Yusuf; Miroslaw, Barbara; Çırak, Çağrı; Doğan, Hatice; Szulczyk, Daniel; Struga, Marta

    2014-07-15

    In this study, the experimental and theoretical vibrational spectral analysis of 4-(3-fluorophenyl)-1-(propan-2-ylidene)-thiosemicarbazone have been carried out. The experimental FT-IR (4000-400 cm(-1)) and Laser-Raman spectra (4000-100 cm(-1)) have been recorded for the solid state samples. The theoretical vibrational frequencies and the optimized geometric parameters (bond lengths and angles) have been calculated for gas phase using density functional theory (DFT/B3LYP: Becke, 3-parameter, Lee-Yang-Parr) and M06-2X (the highly parametrized, empirical exchange correlation function) quantum chemical methods with 6-311++G(d,p) basis set. The diversity in molecular geometry of fluorophenyl substituted thiosemicarbazones has been discussed based on the X-ray crystal structure reports and theoretical calculation results from the literature. The assignments of the vibrational frequencies have been done on the basis of potential energy distribution (PED) analysis by using VEDA4 software. A good correlation was found between the computed and experimental geometric and vibrational data. In addition, the highest occupied (HOMO) and lowest unoccupied (LUMO) molecular orbital energy levels and other related molecular energy values of the compound have been determined using the same level of theoretical calculations. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Spectroscopic studies (FT-IR, FT-Raman, UV-Visible), normal co-ordinate analysis, first-order hyperpolarizability and HOMO, LUMO studies of 3,4-dichlorobenzophenone by using Density Functional Methods.

    Science.gov (United States)

    Venkata Prasad, K; Samatha, K; Jagadeeswara Rao, D; Santhamma, C; Muthu, S; Mark Heron, B

    2015-01-01

    The vibrational frequencies of 3,4-dichlorobenzophenone (DCLBP) were obtained from the FT-IR and Raman spectral data, and evaluated based on the Density Functional Theory using the standard method B3LYP with 6-311+G(d,p) as the basis set. On the basis of potential energy distribution together with the normal-co-ordinate analysis and following the scaled quantum mechanical force methodology, the assignments for the various frequencies were described. The values of the electric dipole moment (μ) and the first-order hyperpolarizability (β) of the molecule were computed. The UV-absorption spectrum was also recorded to study the electronic transitions. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. The NBO analysis, to study the intramolecular hyperconjugative interactions, was carried out. Mulliken's net charges were evaluated. The MEP and thermodynamic properties were also calculated. The electron density-based local reactivity descriptor, such as Fukui functions, was calculated to explain the chemical selectivity or reactivity site in 3,4-dichlorobenzophenone. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. An Object-Based Image Analysis Method for Monitoring Land Conversion by Artificial Sprawl Use of RapidEye and IRS Data

    Directory of Open Access Journals (Sweden)

    Maud Balestrat

    2012-02-01

    Full Text Available In France, in the peri-urban context, urban sprawl dynamics are particularly strong with huge population growth as well as a land crisis. The increase and spreading of built-up areas from the city centre towards the periphery takes place to the detriment of natural and agricultural spaces. The conversion of land with agricultural potential is all the more worrying as it is usually irreversible. The French Ministry of Agriculture therefore needs reliable and repeatable spatial-temporal methods to locate and quantify loss of land at both local and national scales. The main objective of this study was to design a repeatable method to monitor land conversion characterized by artificial sprawl: (i We used an object-based image analysis to extract artificial areas from satellite images; (ii We built an artificial patch that consists of aggregating all the peripheral areas that characterize artificial areas. The “artificialized” patch concept is an innovative extension of the urban patch concept, but differs in the nature of its components and in the continuity distance applied; (iii The diachronic analysis of artificial patch maps enables characterization of artificial sprawl. The method was applied at the scale of four departments (similar to provinces along the coast of Languedoc-Roussillon, in the South of France, based on two satellite datasets, one acquired in 1996–1997 (Indian Remote Sensing and the other in 2009 (RapidEye. In the four departments, we measured an increase in artificial areas of from 113,000 ha in 1997 to 133,000 ha in 2009, i.e., an 18% increase in 12 years. The package comes in the form of a 1/15,000 valid cartography, usable at the scale of a commune (the smallest territorial division used for administrative purposes in France that can be adapted to departmental and regional scales. The method is reproducible in homogenous spatial-temporal terms, so that it could be used periodically to assess changes in land conversion

  9. QM/MM methodology, docking and spectroscopic (FT-IR/FT-Raman, NMR, UV) and Fukui function analysis on adrenergic agonist

    Science.gov (United States)

    Uma Maheswari, J.; Muthu, S.; Sundius, Tom

    2015-02-01

    The Fourier transform infrared, FT-Raman, UV and NMR spectra of Ternelin have been recorded and analyzed. Harmonic vibrational frequencies have been investigated with the help of HF with 6-31G (d,p) and B3LYP with 6-31G (d,p) and LANL2DZ basis sets. The 1H and 13C nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by GIAO method. The polarizability (α) and the first hyperpolarizability (β) values of the investigated molecule have been computed using DFT quantum mechanical calculations. Stability of the molecule arising from hyper conjugative interactions, and charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The electron density-based local reactivity descriptors such as Fukui functions were calculated to explain the chemical selectivity or reactivity site in Ternelin. Finally the calculated results were compared to simulated infrared and Raman spectra of the title compound which show good agreement with observed spectra. Molecular docking studies have been carried out in the active site of Ternelin and reactivity with ONIOM was also investigated.

  10. An Analysis of Laser-Welded Nicr-Ir and Nicr-Pt Micro Joints on Spark Plug Electrodes in Biogas-Fuelled Engines

    Directory of Open Access Journals (Sweden)

    Grabas B.

    2016-06-01

    Full Text Available The paper deals with the laser beam welding of tips to central and side spark plug electrodes made of a nickel-chromium alloy. The tips attached to the central electrodes were made from a solid iridium wire 0.8 mm in diameter and 2 mm in length, while the tips connected to the side electrodes were made from a platinum wire 1.5 mm in diameter and 0.25 mm in thickness. In both cases, accurate positioning of the tips was required before they were resistance welded to the electrodes. Then, a fillet weld was produced with an Nd:YAG laser using single, partly overlapping conductive pulses. The laser welding was performed at different laser power levels and pulse durations. Metallographic sections of the joints were prepared to observe changes in the microstructure and determine their correlation with the changes in the process parameters. The results were used to select appropriate welding parameters for the materials joined. The microscopic analysis indicated welding imperfections such as micro cracks at the interface between the elements joined. The tips welded to the spark plug electrodes can help extend the service life of spark plugs in highly corrosive environments.

  11. Determining the amount of Br, Na and K in six wheat samples with neutron activation analysis (NAA) method in Arak, I.R. Iran

    International Nuclear Information System (INIS)

    Reza Pourimani; Khatoon Abasnejad; Khadijeh Ghanbarzadeh; Mohammad Reza Zare; Mahdi Kamali

    2013-01-01

    Accurate knowledge of the trace elemental concentrations in wheat and its products is of great importance from a nutritional point of view. In this study, six wheat samples were prepared from the agriculture research center of Arak named Sardari, Amir, MV-17, Batava, Karaj-2 and Alvand; they were analyzed by neutron activation method (NAA). In this method, Isfahan miniature reactor as a neutron source and relative NAA method has been used as the analysis type. In this design in order to record gamma spectrum the MCA system and high purity germanium detector were used. Finally, the concentration of the trace elements such as Br, K and Na value was determined for the Sardari, Amir, Alvand, MV-17, Batava, Karaj-2 wheat samples. The average concentration of trace elements in all wheat samples in the studied area are 2.41(0.8597-6.1175) mg kg -1 for Br, 13.42(8.7063-24.696) mg kg -1 for Na and 463.30(434.22-505.45) mg kg -1 for K, respectively. These were compared with other reports results. This study has been conducted as the first time for this region. (author)

  12. A Data-driven Study of RR Lyrae Near-IR Light Curves: Principal Component Analysis, Robust Fits, and Metallicity Estimates

    Science.gov (United States)

    Hajdu, Gergely; Dékány, István; Catelan, Márcio; Grebel, Eva K.; Jurcsik, Johanna

    2018-04-01

    RR Lyrae variables are widely used tracers of Galactic halo structure and kinematics, but they can also serve to constrain the distribution of the old stellar population in the Galactic bulge. With the aim of improving their near-infrared photometric characterization, we investigate their near-infrared light curves, as well as the empirical relationships between their light curve and metallicities using machine learning methods. We introduce a new, robust method for the estimation of the light-curve shapes, hence the average magnitudes of RR Lyrae variables in the K S band, by utilizing the first few principal components (PCs) as basis vectors, obtained from the PC analysis of a training set of light curves. Furthermore, we use the amplitudes of these PCs to predict the light-curve shape of each star in the J-band, allowing us to precisely determine their average magnitudes (hence colors), even in cases where only one J measurement is available. Finally, we demonstrate that the K S-band light-curve parameters of RR Lyrae variables, together with the period, allow the estimation of the metallicity of individual stars with an accuracy of ∼0.2–0.25 dex, providing valuable chemical information about old stellar populations bearing RR Lyrae variables. The methods presented here can be straightforwardly adopted for other classes of variable stars, bands, or for the estimation of other physical quantities.

  13. Characterization and identification of microorganisms by FT-IR microspectrometry

    Science.gov (United States)

    Ngo-Thi, N. A.; Kirschner, C.; Naumann, D.

    2003-12-01

    We report on a novel FT-IR approach for microbial characterization/identification based on a light microscope coupled to an infrared spectrometer which offers the possibility to acquire IR-spectra of microcolonies containing only few hundred cells. Microcolony samples suitable for FT-IR microspectroscopic measurements were obtained by a replica technique with a stamping device that transfers spatially accurate cells of microcolonies growing on solid culture plates to a special, IR-transparent or reflecting stamping plate. High quality spectra could be recorded either by applying the transmission/absorbance or the reflectance/absorbance mode of the infrared microscope. Signal to noise ratios higher than 1000 were obtained for microcolonies as small as 40 μm in diameter. Reproducibility levels were established that allowed species and strain identification. The differentiation and classification capacity of the FT-IR microscopic technique was tested for different selected microorganisms. Cluster and factor analysis methods were used to evaluate the complex spectral data. Excellent discrimination between bacteria and yeasts, and at the same time Gram-negative and Gram-positive bacterial strains was obtained. Twenty-two selected strains of different species within the genus Staphylococcus were repetitively measured and could be grouped into correct species cluster. Moreover, the results indicated that the method allows also identifications at the subspecies level. Additionally, the new approach allowed spectral mapping analysis of single colonies which provided spatially resolved characterization of growth heterogeneity within complex microbial populations such as colonies.

  14. Quantum mechanical and spectroscopic (FT-IR, FT-Raman) study, NBO analysis, HOMO-LUMO, first order hyperpolarizability and molecular docking study of methyl[(3R)-3-(2-methylphenoxy)-3-phenylpropyl]amine by density functional method

    Science.gov (United States)

    Kuruvilla, Tintu K.; Prasana, Johanan Christian; Muthu, S.; George, Jacob; Mathew, Sheril Ann

    2018-01-01

    Quantum chemical techniques such as density functional theory (DFT) have become a powerful tool in the investigation of the molecular structure and vibrational spectrum and are finding increasing use in application related to biological systems. The Fourier transform infrared (FT-IR) and Fourier transform Raman (FT-Raman) techniques are employed to characterize the title compound. The vibrational frequencies were obtained by DFT/B3LYP calculations with 6-31G(d,p) and 6-311 ++G(d,p) as basis sets. The geometry of the title compound was optimized. The vibrational assignments and the calculation of Potential Energy Distribution (PED) were carried out using the Vibrational Energy Distribution Analysis (VEDA) software. Molecular electrostatic potential was calculated for the title compound to predict the reactive sites for electrophilic and nucleophilic attack. In addition, the first-order hyperpolarizability, HOMO and LUMO energies, Fukui function and NBO were computed. The thermodynamic properties of the title compound were calculated at different temperatures, revealing the correlations between heat capacity (C), entropy (S) and enthalpy changes (H) with temperatures. Molecular docking studies were also conducted as part of this study. The paper further explains the experimental results which are in line with the theoretical calculations and provide optimistic evidence through molecular docking that the title compound can act as a good antidepressant. It also provides sufficient justification for the title compound to be selected as a good candidate for further studies related to NLO properties.

  15. FT-IR and Raman vibrational analysis, B3LYP and M06-2X simulations of 4-bromomethyl-6-tert-butyl-2H-chromen-2-one

    Science.gov (United States)

    Sert, Yusuf; Puttaraju, K. B.; Keskinoğlu, Sema; Shivashankar, K.; Ucun, Fatih

    2015-01-01

    In this study, the experimental and theoretical vibrational frequencies of a newly synthesized bacteriostatic and anti-tumor molecule namely, 4-bromomethyl-6-tert-butyl-2H-chromen-2-one have been investigated. The experimental FT-IR (4000-400 cm-1) and Raman spectra (4000-100 cm-1) of the compound in solid phase have been recorded. The theoretical vibrational frequencies and optimized geometric parameters have been calculated using density functional theory (DFT/B3LYP: Becke, 3-parameter, Lee-Yang-Parr and DFT/M06-2X: highly parametrized, empirical exchange correlation function) with 6-311++G(d, p) basis set by Gaussian 03 software, for the first time. The assignments of the vibrational frequencies have been done by potential energy distribution (PED) analysis using VEDA 4 software. The theoretical optimized geometric parameters and vibrational frequencies have been found to be in good agreement with the corresponding experimental data and results in the literature. In addition, the highest occupied molecular orbital (HOMO) energy, the lowest unoccupied molecular orbital (LUMO) energy and the other related molecular energy values of the compound have been investigated using the same theoretical calculations.

  16. Experimental FT-IR, Laser-Raman and DFT spectroscopic analysis of a potential chemotherapeutic agent 6-(2-methylpropyl)-4-oxo-2-sulfanylidene-1,2,3,4-tetrahydropyrimidine-5-carbonitrile.

    Science.gov (United States)

    Sert, Yusuf; Al-Turkistani, Abdulghafoor A; Al-Deeb, Omar A; El-Emam, Ali A; Ucun, Fatih; Çırak, Çağrı

    2014-01-01

    In this study, the experimental and theoretical vibrational frequencies of a newly synthesized potential chemotherapeutic agent namely, 6-(2-methylpropyl)-4-oxo-2-sulfanylidene-1,2,3,4-tetrahydropyrimidine-5-carbonitrile have been investigated. The experimental FT-IR (4000-400 cm(-1)) and Laser-Raman spectra (4000-100 cm(-1)) of the molecule in solid phase have been recorded. The theoretical vibrational frequencies and optimized geometric parameters (bond lengths and bond angles) have been calculated by using density functional theory (DFT/B3LYP: Becke, 3-parameter, Lee-Yang-Parr) and M06-2X (the highly parametrized, empirical exchange correlation function) quantum chemical methods with 6-311++G(d,p) basis set by Gaussian 09 W software, for the first time. The assignments of the vibrational frequencies have been done by potential energy distribution (PED) analysis by using VEDA 4 software. The theoretical optimized geometric parameters and vibrational frequencies have been found to be in good agreement with the corresponding experimental data, and with the results in the literature. In addition, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energies and the other related molecular energy values have been calculated and depicted. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. PENDIDIKAN AKHLAK MUSLIMAT MELALUISYA’IR : ANALISIS GENDER ATAS AJARAN SYI’IR MUSLIMAT KARYA NYAI WANIFAH KUDUS

    Directory of Open Access Journals (Sweden)

    Nur Said

    2016-03-01

    Full Text Available Penelitian ini difokuskan pada tiga hal: (1 Apakah karakteristik lingkup isi Syi’ir Muslimat?, (2 Bagai-manakah kondisi sosial budaya pada saat naskah ditulis oleh penulis?, (3 Apa nilai-nilai pendidikan moral bagi perempuan Muslim di isi Syi’ir Muslimat dalam perspektif gender?. Penelitian ini menggunakan pendekatan filologi dengan meningkatkan penggunaan analisis gender. Hasil dari penelitian ini adalah: Pertama, Syi’ir Muslimat ditulis oleh Nyai Wanifah, seorang wanita yang hidup pada zaman kolonial Belanda dipesantren tradisi di Kudus, Jawa Tengah. Kedua, beberapa nilai pendidikan moral di Syi’ir Muslimatantara lain: (1 Pentingnya pendidikan moral, (2 Bahaya perempuan bodoh; (3 Pentingnya belajar bagi perempuan di usia dini, (4 Etika menghias diri; (5 Bahaya materialisme, (6 Etika hubungan keluarga; (7 Dari rumah untuk mencapai surga; (8 Berhati-hatilah dengan tipu iblis; (9 Hindari perzinahan; (10 yang penting dari penutupan aurot; (11 yang ditujukan kepada orang tua. Ketiga, meskipun ada beberapa senyawa yang bias gender dalam Syi’ir Muslimat misalnya: (a Ada penjelasan yang menunjukkan bahwa perempuan lebih rendah dibandingkan laki-laki dalam derajat, (2 Pernyataan bahwa wanita bicara dibandingkan laki-laki, (3 wanita hanya cocok di wilayah domestik; Namun secara umum nasihat di syi’ir masih sangat relafen dalam konteks sekarang, terutama untuk memberikan solusi alternatif dalam merespon krisis moral bangsa terutama pada wanita generasi muda. Kata kunci: Syi’ir Muslimat, Pendidikan Karakter, Analisis Gender. This study focused on three things: (1 What is the characteristics of the scope of contents of Syi’ir Muslimat?, (2 What is the socio-cultural conditions at the time the manuscript was written by the author?, (3 What are the moral education values for Muslim women in the content of Syi’ir Muslimat in the perspective of gender?. This research uses a philological approach with enhanced use of gender analysis. The

  18. A novel IrNi@PdIr/C core-shell electrocatalyst with enhanced activity and durability for the hydrogen oxidation reaction in alkaline anion exchange membrane fuel cells.

    Science.gov (United States)

    Qin, Bowen; Yu, Hongmei; Jia, Jia; Jun, Chi; Gao, Xueqiang; Yao, Dewei; Sun, Xinye; Song, Wei; Yi, Baolian; Shao, Zhigang

    2018-03-08

    Herein, a novel non-platinum core-shell catalyst, namely, IrNi@PdIr/C was prepared via a galvanic replacement reaction; it exhibits enhanced hydrogen oxidation activity and excellent stability under alkaline conditions. Electrochemical experiments demonstrated that the mass and specific activities at 50 mV of IrNi@PdIr/C are 2.1 and 2.2 times that of commercial Pt/C in 0.1 M KOH at 298 K, respectively. Moreover, accelerated degradation tests have shown that the electrochemically active surface area (ECSA) of IrNi@PdIr/C reduces by only 5.1%, which is almost 4 times less than that of commercial Pt/C and the mass activity at 50 mV of IrNi@PdIr/C after 2000 potential cycles is still 1.8 times higher than that of aged Pt/C. XRD and XPS analysis suggest that the enhanced HOR activity is attributed to the weakening of the hydrogen binding to the PdIr overlayers induced by the IrNi core. The better stability to potential cycling can be associated with the PdIr shell, which inhibits oxide formation. These results suggest that IrNi@PdIr/C is a promising non-platinum anode catalyst for alkaline anion exchange membrane fuel cells.

  19. Reading handprinted addresses on IRS tax forms

    Science.gov (United States)

    Ramanaprasad, Vemulapati; Shin, Yong-Chul; Srihari, Sargur N.

    1996-03-01

    The hand-printed address recognition system described in this paper is a part of the Name and Address Block Reader (NABR) system developed by the Center of Excellence for Document Analysis and Recognition (CEDAR). NABR is currently being used by the IRS to read address blocks (hand-print as well as machine-print) on fifteen different tax forms. Although machine- print address reading was relatively straightforward, hand-print address recognition has posed some special challenges due to demands on processing speed (with an expected throughput of 8450 forms/hour) and recognition accuracy. We discuss various subsystems involved in hand- printed address recognition, including word segmentation, word recognition, digit segmentation, and digit recognition. We also describe control strategies used to make effective use of these subsystems to maximize recognition accuracy. We present system performance on 931 address blocks in recognizing various fields, such as city, state, ZIP Code, street number and name, and personal names.

  20. Multichannel Dynamic Fourier-Transform IR Spectrometer

    Science.gov (United States)

    Balashov, A. A.; Vaguine, V. A.; Golyak, Il. S.; Morozov, A. N.; Khorokhorin, A. I.

    2017-09-01

    A design of a multichannel continuous scan Fourier-transform IR spectrometer for simultaneous recording and analysis of the spectral characteristics of several objects is proposed. For implementing the design, a multi-probe fiber is used, constructed from several optical fibers connected into a single optical connector and attached at the output of the interferometer. The Fourier-transform spectrometer is used as a signal modulator. Each fiber is individually mated with an investigated sample and a dedicated radiation detector. For the developed system, the radiation intensity of the spectrometer is calculated from the condition of the minimum spectral resolution and parameters of the optical fibers. Using the proposed design, emission spectra of a gas-discharge neon lamp have been recorded using a single fiber 1 mm in diameter with a numerical aperture NA = 0.22.

  1. Studies of IR-screening smoke clouds

    Energy Technology Data Exchange (ETDEWEB)

    Cudzilo, S. [Military Univ. of Technology, Warsaw (Poland)

    2001-02-01

    This paper contains some results of research on the IR-screening capability of smoke clouds generated during the combustion process of varied pyrotechnic formulations. The smoke compositions were made from some oxygen or oxygen-free mixtures containing metal and chloroorganic compounds or mixtures based on red phosphorus. The camouflage effectiveness of clouds generated by these formulations was investigated under laboratory conditions with an infrared camera. The technique employed enables determination of radiant temperature distributions in a smoke cloud treated as an energy equivalent of a grey body emission. The results of the analysis of thermographs from the camera were the basis on which the mixtures producing screens of the highest countermeasure for thermal imaging systems have been chosen. (orig.)

  2. Innovations in IR projector arrays

    Science.gov (United States)

    Cole, Barry E.; Higashi, B.; Ridley, Jeff A.; Holmen, J.; Newstrom, K.; Zins, C.; Nguyen, K.; Weeres, Steven R.; Johnson, Burgess R.; Stockbridge, Robert G.; Murrer, Robert Lee; Olson, Eric M.; Bergin, Thomas P.; Kircher, James R.; Flynn, David S.

    2000-07-01

    In the past year, Honeywell has developed a 512 X 512 snapshot scene projector containing pixels with very high radiance efficiency. The array can operate in both snapshot and raster mode. The array pixels have near black body characteristics, high radiance outputs, broad band performance, and high speed. IR measurements and performance of these pixels will be described. In addition, a vacuum probe station that makes it possible to select the best die for packaging and delivery based on wafer level radiance screening, has been developed and is in operation. This system, as well as other improvements, will be described. Finally, a review of the status of the present projectors and plans for future arrays is included.

  3. Thermogravimetric Characterization of the Microstructui Composition of Polyamide Injection Molded Denture Base Material vs Conventional Compression Molded Heat-cured Denture Base Material.

    Science.gov (United States)

    Al-Dharrab, Ayman; Shinawi, Lana

    2016-02-01

    Thermoplastic resin polymers are widely used in medicine due to their biostability and hypoallergenic properties, making them a possible alternative to poly-methylmethacrylate (PMMA). The current research examined the microstructure of a rapid injection molding system thermoplastic resin for construction of flexible denture compared with that of heat-cured PMMA. A total of 40 disk-shaped specimens (25 mm in diameter and 3 mm in thickness) were prepared and divided into two groups of 20 disks each (group I samples were of thermoplastic acrylic resin while group II was heat-cured PMMA resin). In group I, thermogravimetric analyzer showed that increasing the temperature up to 169°C resulted in about 1.3% of the material loss, and after that the material remains thermally stable up to 200°C. Group 11 showed 2.24% weight loss at 171°C, and further weight loss (12.025%) was observed on heating to 230°C. Fourier transform infrared (FTIR) spectrophotometer analysis in the range of 400-4000 cm(-1) detected the presence of an amine group (N-H) in group I samples and the presence of methylene group attached to inorganic Si as reinforcement filler (Si-CH3). Thermoplastic resin displayed excellent thermal stability and the absence of residual monomer within the polymerized material, suggesting its suitability for the fabrication dentures.

  4. Thermogravimetric and Magnetic Studies of the Oxidation and Reduction Reaction of SmCoO3 to Nanostructured Sm2O3 and Co

    Science.gov (United States)

    Kelly, Brian; Cichocki, Ronald; Poirier, Gerald; Unruh, Karl

    The SmCoO3 to nanostructured Sm2O3 and Co oxidation and reduction reaction has been studied by thermogravimetric analysis (TGA) measurements in forming gas (FG) and inert N2 atmospheres, x-ray diffraction (XRD) and vibrating sample magnetometry (VSM). The TGA measurements showed two clearly resolvable reduction processes when heating in FG, from the initial SmCoO3 phase through an intermediate nanostructured mixture of Sm2O3 and CoO when heated to 330°C for several minutes, and then the conversion of CoO to metallic Co when heated above 500°C. These phases were confirmed by XRD and VSM. Similar measurements in N2 yielded little mass change below 900°C and coupled reduction processes at higher temperatures. Isoconversional measurements of the CoO to Co reduction reaction in FG yielded activation energies above 2eV/atom in the nanostructured system. This value is several times larger than those reported in the literature or obtained by similar measurements of bulk mixtures of Sm2O3 and CoO, suggesting the nanostructuring was the source of the large increase in activation energy.

  5. Quantum mechanical study of the structure and spectroscopic (FT-IR, FT-Raman, 13C, 1H and UV), first order hyperpolarizabilities, NBO and TD-DFT analysis of the 4-methyl-2-cyanobiphenyl.

    Science.gov (United States)

    Sebastian, S; Sundaraganesan, N; Karthikeiyan, B; Srinivasan, V

    2011-02-01

    The Fourier transform infrared (FT-IR) and FT-Raman of 4-methyl-2-cyanobiphenyl (4M2CBP) have been recorded and analyzed. The equilibrium geometry, bonding features and harmonic vibrational frequencies have been investigated with the help of density functional theory (DFT) method. The assignments of the vibrational spectra have been carried out with the help of normal coordinate analysis (NCA) following the scaled quantum mechanical force field methodology (SQMFF). The 1H and 13C nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by the Gauge including atomic orbital (GIAO) method. The first order hyperpolarizability (β0) of this novel molecular system and related properties (β, α0 and Δα) of 4M2CBP are calculated using HF/6-311G(d,p) method on the finite-field approach. Stability of the molecule arising from hyperconjugative interactions, charge delocalization have been analyzed using natural bond orbital (NBO) analysis. The results show that charge in electron density (ED) in the σ* and π* antibonding orbitals and second order delocalization energies (E2) confirms the occurrence of intramolecular charge transfer (ICT) within the molecule. UV-vis spectrum of the compound was recorded and the electronic properties, such as HOMO and LUMO energies, were performed by time-dependent density functional theory (TD-DFT) approach. Finally the calculations results were applied to simulated infrared and Raman spectra of the title compound which show good agreement with observed spectra. Copyright © 2010 Elsevier B.V. All rights reserved.

  6. Microscale Solubility Measurements of Matrix-Assisted Laser Desorption-Ionization (MALDI) Matrices Using Attenuated Total Reflection (ATR) Fourier Transform Infrared Spectroscopy (FT-IR) Coupled with Partial Least Squares (PLS) Analysis.

    Science.gov (United States)

    Gorre, Elsa; Owens, Kevin G

    2016-11-01

    In this work an attenuated total reflection Fourier transform infrared (FT-IR) absorption based method is used to measure the solubility of two matrix-assisted laser desorption-ionization (MALDI) matrices in a few pure solvents and mixtures of acetonitrile and water using low microliter amounts of solution. Results from a method that averages the values obtained from multiple calibration curves created by manual peak picking are compared to those predicted using a partial least squares (PLS) chemometrics approach. The PLS method provided solubility values that were in good agreement with the manual method with significantly greater ease of analysis. As a test, the solubility of adipic acid in acetone was measured using the two methods of analysis, and the values are in good agreement with solubility values reported in literature. The solubilities of the MALDI matrices α-cyano-4-hydroxy cinnamic acid (CHCA) and sinapinic acid (SA) were measured in a series of mixtures made from acetonitrile (ACN) and water; surprisingly, the results show a highly nonlinear trend. While both CHCA and SA show solubility values of less than 10 mg/mL in the pure solvents, the solubility value for SA increases to 56.3 mg/mL in a 75:25 v/v ACN:water mixture. This can have a significant effect on the matrix-to-analyte ratios in the MALDI experiment when sample protocols call for preparation of a saturated solution of the matrix in the chosen solvent system. © The Author(s) 2016.

  7. STATYBINIŲ MEDŽIAGŲ KONKURENCINGUMAS IR TENDENCIJOS

    OpenAIRE

    Kontrimas, Robertas

    2010-01-01

    Darbe analizuojamas statybinių medžiagų konkurencingumas, nustatyti statybinių medžiagų konkurencingumą įtakojantys veiksniai ir pateikti pasiūlymai rinkos gerinimui. Pasitvirtino hipotezė, kad statybinių medžiagų paklausą ir kainas įtakoja klientų poreikiai ir jų finansinės galimybės, tačiau pasaulinės krizės įtaka yra labai ženkli,. Atlikta darbuotojų ir pirkėjų apklausa padėjo nustatyti, kokios statybinės medžiagos dažniausiai yra perkamos, kaip klientai ir darbuotojai vertina įmonę ir jos...

  8. Hermann agreement updates IRS guidelines for incentives.

    Science.gov (United States)

    Broccolo, B M; Peregrine, M W

    1995-01-01

    The October 1994 agreement between the Internal Revenue Service (IRS) and Hermann Hospital of Houston, Texas, elucidates current IRS policy on physician recruitment incentives. The IRS distinguishes between the recruiting and the retention of physicians and perimts incentives beyond reasonable compensation in the former but not the latter circumstance. This new agreement, while not legally precedential, nevertheless provides guidance for healthcare organizations seeking safe harbor protection.

  9. Molecular structure, vibrational, HOMO-LUMO, MEP and NBO analysis of hafnium selenite

    Science.gov (United States)

    Yankova, Rumyana; Genieva, Svetlana; Dimitrova, Ginka

    2017-08-01

    In hydrothermal condition hafnium selenite with estimated chemical composition Hf(SeO3)2·n(H2O) was obtained and characterized by powder X-Ray diffraction, IR spectroscopy and thermogravimetrical analysis. The composition of the obtained crystalline phase was established as dihydrate of tetraaqua complex of the hafnium selenite [Hf(SeO3)2(H2O)4]·2H2O. The results of the thermogravimetrical analysis are shown that the two hydrated water molecules are released in the temperature interval 80-110°C, while the four coordinated water molecules - at 210-300°C. By DFT method, with Becke's three parameter exchange-functional combined with gradient-corrected correlation functional of Lee, Yang and Parr and 6-31G(d), 6-311 + G(d,p) basis sets and LANL2DZ for Hf atom were calculated the molecular structure, vibrational frequencies and thermodynamic properties of the structure. The UV-Vis spectra and electronic properties are presented. The energy and oscillator strength calculated by time-dependent density functional theory corresponds well with the experimental ones. Molecular electrostatic potential (MEP) was performed. Mulliken population analysis on atomic charges was also calculated. The stability and intramolecular interactions are interpreted by NBO analysis.

  10. Structural, magnetic, and electronic transport properties of pyrochlore iridate Pr2Ir2O7

    Science.gov (United States)

    Kumar, Harish; Chaurasia, Rachna; Kumari, Pratibha; Paramanik, A. K.

    2018-04-01

    We have studied the structural, magnetic, and electronic transport properties of pyrochlore iridate Pr2Ir2O7. Structural investigation has been done using x-ray powder diffraction and Rietveld analysis. Pr2Ir2O7 crystallize in cubic crystallographic phase with Fd-3m space group. Temperature dependent magnetization data does not show magnetic bifurcation down to 2 K. Electrical resistivity data of Pr2Ir2O7 exhibits metallic behavior throughout temperature range. Below 50 K, a small rise in resistivity data of Pr2Ir2O7 is observed down to 12 K.

  11. Atmospheric Entry Experiments at IRS

    Science.gov (United States)

    Auweter-Kurtz, M.; Endlich, P.; Herdrich, G.; Kurtz, H.; Laux, T.; Löhle, S.; Nazina, N.; Pidan, S.

    2002-01-01

    Entering the atmosphere of celestial bodies, spacecrafts encounter gases at velocities of several km/s, thereby being subjected to great heat loads. The thermal protection systems and the environment (plasma) have to be investigated by means of computational and ground facility based simulations. For more than a decade, plasma wind tunnels at IRS have been used for the investigation of TPS materials. Nevertheless, ground tests and computer simulations cannot re- place space flights completely. Particularly, entry mission phases encounter challenging problems, such as hypersonic aerothermodynamics. Concerning the TPS, radiation-cooled materials used for reuseable spacecrafts and ablator tech- nologies are of importance. Besides the mentioned technologies, there is the goal to manage guidance navigation, con- trol, landing technology and inflatable technologies such as ballutes that aim to keep vehicles in the atmosphere without landing. The requirement to save mass and energy for planned interplanetary missions such as Mars Society Balloon Mission, Mars Sample Return Mission, Mars Express or Venus Sample Return mission led to the need for manoeuvres like aerocapture, aero-breaking and hyperbolic entries. All three are characterized by very high kinetic vehicle energies to be dissipated by the manoeuvre. In this field flight data are rare. The importance of these manoeuvres and the need to increase the knowledge of required TPS designs and behavior during such mission phases point out the need of flight experiments. As result of the experience within the plasma diagnostic tool development and the plasma wind tunnel data base, flight experiments like the PYrometric RE-entry EXperiment PYREX were developed, fully qualified and successfully flown. Flight experiments such as the entry spectrometer RESPECT and PYREX on HOPE-X are in the conceptual phase. To increase knowledge in the scope of atmospheric manoeuvres and entries, data bases have to be created combining both

  12. Thermogravimetric method of estimation of uranyl cation state in melts of alkali metal chlorides and their mixtures

    International Nuclear Information System (INIS)

    Vorobej, M.P.; Desyatnik, V.N.

    1979-01-01

    The thermogravimetric method was used to study the chloridizing of uranium oxides in molten media. The study of the uranium oxide chloridizing served as a basis for evaluating comparatively, using the DTA method, the uranyl-cation state in a melt. Using the alkali metals as example, it was shown that the decomposition of the frozen uranium oxychlorides proceeds with the formation of intermediate chlorouranates. The final product of the thermolysis are uranates Me 2 U 2 O 7 (Me-Li, Na, K, Rb, Cs). The time and the conditions of the change of uranium oxides to the oxyanion [UO 2 Cl 4 ] 2- were determined as a function of the chloridizing agent. The method can be employed for evaluating uranyl-ions in molten media where they are used as electrolytes in the extraction of uranium dioxide

  13. Teaching IR to Medical Students: A Call to Action.

    Science.gov (United States)

    Lee, Aoife M; Lee, Michael J

    2018-02-01

    Interventional radiology (IR) has grown rapidly over the last 20 years and is now an essential component of modern medicine. Despite IR's increasing penetration and reputation in healthcare systems, IR is poorly taught, if taught at all, in most medical schools. Medical students are the referrers of tomorrow and potential IR recruits and deserve to be taught IR by expert IRs. The lack of formal IR teaching curricula in many medical schools needs to be addressed urgently for the continued development and dissemination of, particularly acute, IR services throughout Europe. We call on IRs to take up the baton to teach IR to the next generation of doctors.

  14. Premier's imaging IR limb sounder

    Science.gov (United States)

    Kraft, Stefan; Bézy, Jean-Loup; Meynart, Roland; Langen, Jörg; Carnicero Dominguez, Bernardo; Bensi, Paolo; Silvestrin, Pierluigi

    2017-11-01

    The Imaging IR Limb Sounder (IRLS) is one of the two instruments planned on board of the candidate Earth Explorer Core Mission PREMIER. PREMIER stands for PRocess Exploration through Measurements of Infrared and Millimetre-wave Emitted Radiation. PREMIER went recently through the process of a feasibility study (Phase A) within the Earth Observation Envelope Program. Emerging from recent advanced instrument technologies IRLS shall, next to a millimetre-wave limb sounder (called STEAMR), explore the benefits of three-dimensional limb sounding with embedded cloud imaging capability. Such 3D imaging technology is expected to open a new era of limb sounding that will allow detailed studies of the link between atmospheric composition and climate, since it will map simultaneously fields of temperature and many trace gases in the mid/upper troposphere and stratosphere across a large vertical and horizontal field of view and with high vertical and horizontal resolution. PREMIER shall fly in a tandem formation looking backwards to METOP's swath and thereby improve meteorological and environmental analyses.

  15. Atom condensation on an atomically smooth surface: Ir, Re, W, and Pd on Ir(111)

    International Nuclear Information System (INIS)

    Wang, S.C.; Ehrlich, G.

    1991-01-01

    The distribution of condensing metal atoms over the two types of sites present on an atomically smooth Ir(111) has been measured in a field ion microscope. For Ir, Re, W, and Pd from a thermal source, condensing on Ir(111) at ∼20 K, the atoms are randomly distributed, as expected if they condense at the first site struck

  16. Biochemical applications of FT-IR spectroscopy

    NARCIS (Netherlands)

    Pistorius, A.M.A.

    1996-01-01

    This thesis describes the use of (FT-)IR spectroscopy in general biochemical research. In chapter 3, IR spectroscopy is used in the quantitation of residual detergent after reconstitution of an integral membrane protein in a pre-defined lipid matrix. This chapter discusses the choice of the

  17. How to remedy Eurocentrism in IR?

    DEFF Research Database (Denmark)

    Bilgin, Pinar

    2016-01-01

    While IR's Eurocentric limits are usually acknowledged, what those limits mean for theorizing about the international is seldom clarified. In The Global Transformation, Buzan and Lawson offer a 'composite approach' that goes some way towards addressing IR's Eurocentrism, challenging existing myth...

  18. Benzene adsorption and oxidation on Ir(111)

    NARCIS (Netherlands)

    Weststrate, C.J.; Bakker, J.W.; Gluhoi, A.C.; Ludwig, W.; Nieuwenhuys, B.E.

    2007-01-01

    Adsorption, decompn. and oxidn. of benzene on Ir(1 1 1) was studied by high resoln. (synchrotron) XPS, temp. programmed desorption and LEED. Mol. adsorption of benzene on Ir(1 1 1) is obsd. between 170 K and 350 K. Above this temp. both desorption and decompn. of benzene take place. An ordered

  19. Smulkaus ir vidutinio verslo konkurencingumas Lietuvoje

    OpenAIRE

    Vijeikis, Juozas; Makštutis, Antanas

    2009-01-01

    Straipsnio mokslinė problema, naujumas ir aktualumas. Konkurencingumas kaip įmonių efektyvios veiklos reiškinys yra aktualus šalies verslo gyvenime vykdant darnios ekonominės plėtros politiką. Ši politika kaip problema smulkaus ir vidutinio verslo (SVV) plėtrai ir konkurencingumui didinti nėra sistemiškai ištirta ir aprašyta Lietuvos sąlygomis mokslinėje ir praktinėje literatūroje. Vienas svarbiausių veiksnių, siekiant spartaus ekonominio augimo, yra darnios verslininkystės plėtra Lietuvoje n...

  20. Tarptautinio turizmo raida ir vystymo prognozės Lietuvoje ir Lenkijoje

    OpenAIRE

    Veličkaitė, Dalia

    2009-01-01

    Išanalizuota ir įvertinta Lietuvos ir Lenkijos atvykstamojo turizmo raida 2000- 2007m., užsienio turistų srautai, apgyvendinimo paslaugų paklausa, turistų tikslai ir kelionių transporto pasirinkimas, turistų išlaidos ir šalių turizmo pajamos, iškeltos atvykstamojo turizmo problemos bei pateikti jų sprendimo siūlymai.paskutinėje darbo dalyje buvo atliktos 2008- 2015metų Lietuvos ir Lenkijos turizmo raidos prognozės. In the final master work Lithuanian and Poland arriving tourism development...

  1. Visualizing Infrared (IR) Spectroscopy with Computer Animation

    Science.gov (United States)

    Abrams, Charles B.; Fine, Leonard W.

    1996-01-01

    IR Tutor, an interactive, animated infrared (IR) spectroscopy tutorial has been developed for Macintosh and IBM-compatible computers. Using unique color animation, complicated vibrational modes can be introduced to beginning students. Rules governing the appearance of IR absorption bands become obvious because the vibrational modes can be visualized. Each peak in the IR spectrum is highlighted, and the animation of the corresponding normal mode can be shown. Students can study each spectrum stepwise, or click on any individual peak to see its assignment. Important regions of each spectrum can be expanded and spectra can be overlaid for comparison. An introduction to the theory of IR spectroscopy is included, making the program a complete instructional package. Our own success in using this software for teaching and research in both academic and industrial environments will be described. IR Tutor consists of three sections: (1) The 'Introduction' is a review of basic principles of spectroscopy. (2) 'Theory' begins with the classical model of a simple diatomic molecule and is expanded to include larger molecules by introducing normal modes and group frequencies. (3) 'Interpretation' is the heart of the tutorial. Thirteen IR spectra are analyzed in detail, covering the most important functional groups. This section features color animation of each normal mode, full interactivity, overlay of related spectra, and expansion of important regions. This section can also be used as a reference.

  2. Deposition and characterization of IrOx nanofoils on carbon nanotube templates by reactive magnetron sputtering

    International Nuclear Information System (INIS)

    Chen, Yi-Min; Cai, Jhen-Hong; Huang, Ying-Sheng; Lee, Kuei-Yi; Tsai, Dah-Shyang; Tiong, Kwong-Kau

    2012-01-01

    Large surface area IrO x nanofoils (IrO x NF) were deposited on multi-wall carbon nanotube (MWCNT) templates, forming IrO x /MWCNT nanocomposites, by reactive radio frequency magnetron sputtering using Ir metal target. The structural and spectroscopic properties of IrO x NF were characterized. The micrographs of field emission scanning electron microscopy showed the formation of foil-like structure for the as-deposited samples. Transmission electron microscopy analysis revealed the contiguous presence of glassy iridium oxide, iridium metal, and iridium dioxide nanocrystals in the foil. X-ray photoelectron spectroscopy analysis provided the information of the oxidation states and the stoichiometry of IrO x NF. Raman spectra revealed the amorphous-like phase of the as-deposited IrO x NF. The nanofoil structure provided ultra-high surface area for electrical charge storage which made the IrO x /MWCNT nanocomposites as an attractive candidate for the supercapacitor applications.

  3. Synthesis, single crystal X-ray, spectroscopic (FT-IR, UV-vis, fluorescence, 1H &13C NMR), computational (DFT/B3LYP) studies of some imidazole based picrates

    Science.gov (United States)

    Arockia doss, M.; Rajarajan, G.; Thanikachalam, V.; Selvanayagam, S.; Sridhar, B.

    2018-04-01

    2,4,5-triphenyl-1H-imidazol-3-ium picrate (1), 2-(4-fluorophenyl)-4,5-diphenyl-1H-imidazol-3-ium picrate (2), 2-(4-methylphenyl)-4,5-diphenyl-1H-imidazol-3-ium picrate (3) were synthesised. These compounds 1-3 were characterized by elemental, FT-IR, 1H NMR and 13C NMR analyses. The structure of compound 3 was further confirmed by single crystal X-ray diffraction. The studies reveal that the molecule is associated with weak Nsbnd H⋯O and Csbnd H⋯N and van der Waals interactions which are responsible for the formation and strengthening of supramolecular assembly. The nature of the interactions and their importance are explored using the Hirshfeld surface method. The physicochemical properties of the compounds 1-3 were evaluated by UV-vis spectroscopy, fluorescence spectroscopy, and thermogravimetric analysis. According to thermal data the salts possess excellent thermal stabilities with decomposition temperatures ranging from 220 to 280 °C. Second-harmonic generation (SHG) results exposed that the picrates 1-3 were about 1.13-1.50 times greater than potassium dihydrogen phosphate (KDP). Here we also used Density functional theory (DFT) calculations in order to investigate the opto-electronic properties. The obtained theoretical results validate with available experimental data.

  4. Mock Target Window OTR and IR Design and Testing

    Energy Technology Data Exchange (ETDEWEB)

    Wass, Alexander Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-09-19

    In order to fully verify temperature measurements made on the target window using infrared (IR) optical non-contact methods, actual comparative measurements are made with a real beam distribution as the heat source using Argonne National Laboratory’s (ANL) 35 MeV electron accelerator. Using Monte Carlo N-Particle (MCNP) simulations and thermal Finite Element Analysis (FEA), a cooled mock target window with thermocouple implants is designed to be used in such a test to achieve window temperatures up to 700°C. An uncoated and blackcoated mock window is designed to enhance the IR temperature measurements and verify optical transmitted radiation (OTR) imagery. This allows us to fully verify and characterize our temperature accuracy with our current IR camera method and any future method we may wish to explore using actual production conditions. This test also provides us with valuable conclusions/concerns regarding the calibration method we developed using our IR test stand at TA-53 in MPF-14.

  5. Thermogravimetric and Differential Scanning Calorimetric Behavior of Ball-Milled Nuclear Graphite

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eung Seon; Kim, Min Hwan; Kim, Yong Wan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Yi Hyun; Cho, Seung Yon [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    An examination was made to characterize the oxidation behavior of ball-milled nuclear graphite powder through a TG-DSC analysis. With the ball milling time, the BET surface area increased with the reduction of particle size, but decreased with the chemisorptions of O{sub 2} on the activated surface. The enhancement of the oxidation after the ball milling is attributed to both increases in the specific surface area and atomic scale defects in the graphite structure. In a high temperature gas-cooled reactor, nuclear graphite has been widely used as fuel elements, moderator or reflector blocks, and core support structures owing to its excellent moderating power, mechanical properties and machinability. For the same reason, it will be used in a helium cooled ceramic reflector test blanket module for the ITER. Each submodule has a seven-layer breeding zone, including three neutron multiplier layers packed with beryllium pebbles, three lithium ceramic pebbles packed tritium breeder layers, and a reflector layer packed with 1 mm diameter graphite pebbles to reduce the volume of beryllium. The abrasion of graphite structures owing to relative motion or thermal cycle during operation may produce graphite dust. It is expected that graphite dust will be more oxidative than bulk graphite, and thus the oxidation behavior of graphite dust must be examined to analyze the safety of the reactors during an air ingress accident. In this study, the thermal stability of ball-milled graphite powder was investigated using a simultaneous thermogravimeter-differential scanning calorimeter.

  6. Vartotojų lojalumas : formavimas ir valdymas

    OpenAIRE

    Zikienė, Kristina

    2010-01-01

    Vienas iš esminių daugelio organizacijų tikslų, garantuojančių tolesnį sėkmingą konkuravimą nuolat besikeičiančiame verslo pasaulyje, yra vartotojų lojalumo įgijimas ir išlaikymas. Įvairios lojalumo formavimo ir valdymo problemos plačiai ir detaliai analizuojamos šioje mokomojoje knygoje. Knyga pradedama vartotojų lojalumo analize marketingo mokslo raidos kontekste. Tolesnis dėmesys skiriamas vartotojų lojalumo vadybinio aspekto analizei, atskleidžiant vartotojų lojalumo koncepcijos teorines ...

  7. The TApIR experiment. IR absorption spectra of liquid hydrogen isotopologues; Das TApIR Experiment IR-Absorptionsspektren fluessiger Wasserstoffisotopologe

    Energy Technology Data Exchange (ETDEWEB)

    Groessle, Robin

    2015-11-27

    The scope of the thesis is the infrared absorption spectroscopy of liquid hydrogen isotopologues with the tritium absorption infrared spectroscopy (TApIR) experiment at the tritium laboratory Karlsruhe (TLK). The calibration process from the sample preparation to the reference measurements are described. A further issue is the classical evaluation of FTIR absorption spectra and the extension using the rolling circle filter (RCF) including the effects on statistical and systematical errors. The impact of thermal and nuclear spin temperature on the IR absorption spectra is discussed. An empirical based modeling for the IR absorption spectra of liquid hydrogen isotopologues is performed.

  8. Intraarterial 192Ir high-dose-rate brachytherapy for prophylaxis of restenosis after femoropopliteal percutaneous transluminal angioplasty: the prospective randomized Vienna-2-trial radiotherapy parameters and risk factors analysis

    International Nuclear Information System (INIS)

    Pokrajac, Boris; Poetter, Richard; Maca, Thomas; Fellner, Claudia; Mittlboeck, Martina; Ahmadi, Ramazanali; Seitz, Wolfgang; Minar, Erich

    2000-01-01

    Purpose: The aim of the Vienna-2-trial was to compare the restenosis rate of femoropopliteal arteries after percutaneous transluminal angioplasty (PTA) with or without intraarterial high-dose-rate (HDR) brachytherapy (BT) using an 192 Ir source. Materials and Methods: A prospective, randomized trial was conducted from 11/96 to 8/98. A total of 113 patients (63 men, 50 women), with a mean age of 71 years (range, 43-89 years) were included. Inclusion criteria were (1) claudication or critical limb ischemia, (2) de-novo stenosis of 5 cm or more, (3) restenosis after former PTA of any length, and (4) no stent implantation. Patients were randomized after successful PTA for BT vs. no further treatment. A well-balanced patient distribution was achieved for the criteria used for stratification, as there were 'de-novo stenosis vs. restenosis after former PTA', 'stenosis vs. occlusion', 'claudication vs. critical limb ischemia' and above these for 'diabetes vs. nondiabetes'. PTA length was not well balanced between the treatment arms: a PTA length of 4-10 cm was seen in 19 patients in the PTA alone group and in 11 patients in the PTA+BT group, whereas a PTA length of greater than10 cm was seen in 35 patients and 42 patients, respectively. A dose of 12 Gy was prescribed in 3-mm distance from the source axis. According to AAPM recommendations, the dose was 6.8 Gy in 5-mm distance (vessel radius + 2 mm). Primary endpoint of the study was femoropopliteal patency after 6 months. Results: PTA and additional BT were feasible and well tolerated by all 57 pts in this treatment arm. No acute, subacute, and late adverse side effects related to BT were seen after a mean follow up of 12 months (6-24 months) in 107 patients (PTA n = 54; PTA+ BT n = 53). Crude restenosis rate at 6 months was in the PTA arm 54% vs. 28% in the PTA + BT arm (χ 2 test; p 10 cm) showed significant decrease of the restenosis rate, if BT was added. Significant reduction was not achieved in diabetes patients

  9. Thermogravimetric study on the hydration of reactive magnesia and silica mixture at room temperature

    International Nuclear Information System (INIS)

    Jin, Fei; Al-Tabbaa, Abir

    2013-01-01

    Highlights: • The characteristics of reactive MgO vary significantly in terms of their impurity content and reactivity depending on their sources and calcination conditions. • The synthesis of magnesium silicate hydrate (MSH) is affected by the characteristics of the precursors, i.e., MgO and silica. • The reaction process in the MgO–SiO 2 –H 2 O system can be followed by TGA, and is essential to develop MSH-based materials. - Abstract: The synthesis of magnesium silicate hydrate (MSH), which has wide applications in both construction and environmental fields, has been studied for decades. However, it is known that the characteristics of magnesia (MgO) vary significantly depending on their calcination conditions, which is expected to affect their performance in the MgO–SiO 2 –H 2 O system. This paper investigated the effect of different MgO and silica sources on the formation of magnesium silicate hydrate (MSH) at room temperature. The hydration process was studied by mixing commercial reactive MgO and silica powders with water and curing for 1, 7 and 28 days. The hydration products were analysed with the help of X-ray diffraction (XRD) and thermogravimatric analysis (TGA). The results showed the continuous consumption of MgO and the existence of MSH and brucite and other minor phases such as magnesite and calcite. It is found that the Mg and Si sources have significant effect on the hydration process of MgO–SiO 2 –H 2 O system. The reaction degree is controlled by the availability of dissolved Mg and Si in the solution. The former is determined by the reactivity of MgO and the latter is related to the reactivity of the silica as well as the pH of the system

  10. PKCδ-mediated IRS-1 Ser24 phosphorylation negatively regulates IRS-1 function

    International Nuclear Information System (INIS)

    Greene, Michael W.; Ruhoff, Mary S.; Roth, Richard A.; Kim, Jeong-a; Quon, Michael J.; Krause, Jean A.

    2006-01-01

    The IRS-1 PH and PTB domains are essential for insulin-stimulated IRS-1 Tyr phosphorylation and insulin signaling, while Ser/Thr phosphorylation of IRS-1 disrupts these signaling events. To investigate consensus PKC phosphorylation sites in the PH-PTB domains of human IRS-1, we changed Ser24, Ser58, and Thr191 to Ala (3A) or Glu (3E), to block or mimic phosphorylation, respectively. The 3A mutant abrogated the inhibitory effect of PKCδ on insulin-stimulated IRS-1 Tyr phosphorylation, while reductions in insulin-stimulated IRS-1 Tyr phosphorylation, cellular proliferation, and Akt activation were observed with the 3E mutant. When single Glu mutants were tested, the Ser24 to Glu mutant had the greatest inhibitory effect on insulin-stimulated IRS-1 Tyr phosphorylation. PKCδ-mediated IRS-1 Ser24 phosphorylation was confirmed in cells with PKCδ catalytic domain mutants and by an RNAi method. Mechanistic studies revealed that IRS-1 with Ala and Glu point mutations at Ser24 impaired phosphatidylinositol-4,5-bisphosphate binding. In summary, our data are consistent with the hypothesis that Ser24 is a negative regulatory phosphorylation site in IRS-1

  11. Activity uniformity of Ir-192 seeds

    International Nuclear Information System (INIS)

    Ling, C.C.; Gromadzki, Z.C.

    1981-01-01

    A simple device that uses materials and apparatus commonly available in a radiotherapy department has been designed, fabricated and used in routine quality control relative to the activity uniformity of clinical Ir-192 seeds in ribbons. Detailed evaluation indicated that this system is easy to use and can yield relative activity measurements of individual Ir-192 seeds accurate to within 2%. With this device, activity uniformity of commercial Ir-192 seeds from two manufacturers has been assessed. For the seven shipments of Ir-192 seeds studied, the root mean square variations of individual seed strength from the average of each shipment ranged from 3.4 to 7.1%. Variation in seed activity by more than +- 10% from the average is not uncommon

  12. Implementing GPS into Pave-IR.

    Science.gov (United States)

    2009-03-01

    To further enhance the capabilities of the Pave-IR thermal segregation detection system developed at the Texas Transportation Institute, researchers incorporated global positioning system (GPS) data collection into the thermal profiles. This GPS capa...

  13. Joint IAEA/NEA IRS guidelines

    International Nuclear Information System (INIS)

    1997-01-01

    The Incident Reporting System (IRS) is an international system jointly operated by the International Atomic Energy Agency (IAEA) and the Nuclear Energy Agency of the Organization for Economic Cooperation and Development (OECD/NEA). The fundamental objective of the IRS is to contribute to improving the safety of commercial nuclear power plants (NPPs) which are operated worldwide. This objective can be achieved by providing timely and detailed information on both technical and human factors related to events of safety significance which occur at these plants. The purpose of these guidelines, which supersede the previous IAEA Safety Series No. 93 (Part II) and the NEA IRS guidelines, is to describe the system and to give users the necessary background and guidance to enable them to produce IRS reports meeting a high standard of quality while retaining the high efficiency of the system expected by all Member States operating nuclear power plants

  14. Co-pyrolysis behavior of fermentation residues with woody sawdust by thermogravimetric analysis and a vacuum reactor.

    Science.gov (United States)

    Zheng, Yan; Zhang, Yimin; Xu, Jingna; Li, Xiayang; Charles Xu, Chunbao

    2017-12-01

    This study aimed at cost-effective utilization of fermentation residues (FR) from biogas project for bio-energy via co-pyrolysis of FR and woody sawdust (WS). In this study, a vacuum reactor was used to study the pyrolysis behaviors of individual and blend samples of FR and WS. Obvious synergistic effects were observed, resulting in a lower char yield but a higher gas yield. The presence of woody sawdust promoted the devolatilization of FR, and improved the syngas (H 2 and CO) content in the gaseous products. Compared to those of the char from pyrolysis of individual feedstock, co-pyrolysis of FR and WS in the vacuum reactor promoted the cracking reactions of large aromatic rings, enlarged the surface area and reduced the oxygenated groups of the resulted char. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Botanical trash mixtures analyzed with near-infrared and attenuated total reflectance fourier transform spectroscopy and thermogravimetric analysis

    Science.gov (United States)

    Botanical cotton trash mixed with lint reduces cotton’s marketability and appearance. During cotton harvesting, ginning, and processing, trash size reduction occurs, thus complicating its removal and identification. This trash causes problems by increasing ends down in yarn formation and thus proce...

  16. Co-gasification of biosolids with biomass: Thermogravimetric analysis and pilot scale study in a bubbling fluidized bed reactor.

    Science.gov (United States)

    Yu, Ming Ming; Masnadi, Mohammad S; Grace, John R; Bi, Xiaotao T; Lim, C Jim; Li, Yonghua

    2015-01-01

    This work studied the feasibility of co-gasification of biosolids with biomass as a means of disposal with energy recovery. The kinetics study at 800°C showed that biomass, such as switchgrass, could catalyze the reactions because switchgrass ash contained a high proportion of potassium, an excellent catalyst for gasification. However, biosolids could also inhibit gasification due to interaction between biomass alkali/alkaline earth metals and biosolids clay minerals. In the pilot scale experiments, increasing the proportion of biosolids in the feedstock affected gasification performance negatively. Syngas yield and char conversion decreased from 1.38 to 0.47m(3)/kg and 82-36% respectively as the biosolids proportion in the fuel increased from 0% to 100%. Over the same range, the tar content increased from 10.3 to 200g/m(3), while the ammonia concentration increased from 1660 to 19,200ppmv. No more than 25% biosolids in the fuel feed is recommended to maintain a reasonable gasification. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Thermogravimetric study of thermal decontamination of soils polluted by hexachlorobenzene, 4-chlorobiphenyl, naphthalene, or n-decane.

    Science.gov (United States)

    Risoul, V; Pichon, C; Trouvé, G; Peters, W A; Gilot, P; Prado, G

    1999-02-15

    To determine decontamination behavior as affected by temperature, shallow beds of a clay-rich, a calcerous, and a sedimentary soil, artificially polluted with hexachlorobenzene, 4-chlorobiphenyl, naphthalene, or n-decane, were separately heated at 5 degrees C min-1 in a thermogravimetric analyzer. Temperatures for deep cleaning of the calcerous and the sedimentary soil increased with increasing boiling point (bp) of the aromatic contaminants, but removal efficiencies still approached 100% well below the bp. Decontamination rates were therefore modelled according to a pollutant evaporation-diffusion transport model. For the calcerous and sedimentary soils, this model reasonably correlated removal of roughly the first 2/3 of the naphthalene, but gave only fair predictions for hexachlorobenzene and 4-chlorobiphenyl. It was necessary to heat the clay soil above the aromatics bp to achieve high decontamination efficiencies. Weight loss data imply that for temperatures from near ambient to as much as 150 degrees C, interactions of each aromatic with the clay soil, or its decomposition products, result in lower net volatilization of the contaminated vs. neat clay. A similar effect was observed in heating calcerous soil polluted with hexachlorobenzene from near ambient to about 140 degrees C. Decontamination mechanisms remain to be established, although the higher temperatures needed to remove aromatics from the clay may reflect a more prominent role for surface desorption than evaporation. This would be consistent with our estimates that the clay can accommodate all of the initial pollutant loadings within a single surface monolayer, whereas the calcerous and sedimentary soils cannot.

  18. Effect of biopretreatment on thermogravimetric and chemical characteristics of corn stover by different white-rot fungi.

    Science.gov (United States)

    Yang, Xuewei; Zeng, Yelin; Ma, Fuying; Zhang, Xiaoyu; Yu, Hongbo

    2010-07-01

    The thermogravimetric and chemical characterization of corn stover biopretreated by three different species of white-rot fungi have been studied in this research. Results indicated that biopretreatment can optimize the thermal decomposition, decrease the reaction temperature and reduce the gas contamination (SO(x)), making the biomass pyrolysis more efficient and environmentally friendly. Biopretreatment can decrease the activation energy and reacting temperature of the hemicellulose and cellulose pyrolysis (up to 36 degrees C), shorten the temperature range of the active pyrolysis (up to 14 degrees C), and increase the thermal decomposition rate, greatly promoting the reaction and making the biomass pyrolysis easier to start and carry on. On the other hand, by biopretreatment, the sulphur content can decrease up to 46.15%, which can considerably reduce the inventory of SO(x) emission. Moreover, the mechanism of the biopretreatment was also explored that the deconstruction and depolymerization of the recalcitrant linkages of lignin and cellulose by biopretreatment can make the structure of biomass incompact and easier to be pyrolyzed. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  19. Splitting CO2 with a ceria‐based redox cycle in a solar‐driven thermogravimetric analyzer

    Science.gov (United States)

    Takacs, M.; Ackermann, S.; Bonk, A.; Neises‐von Puttkamer, M.; Haueter, Ph.; Scheffe, J. R.; Vogt, U. F.

    2016-01-01

    Thermochemical splitting of CO2 via a ceria‐based redox cycle was performed in a solar‐driven thermogravimetric analyzer. Overall reaction rates, including heat and mass transport, were determined under concentrated irradiation mimicking realistic operation of solar reactors. Reticulated porous ceramic (RPC) structures and fibers made of undoped and Zr4+‐doped CeO2, were endothermally reduced under radiative fluxes of 1280 suns in the temperature range 1200–1950 K and subsequently re‐oxidized with CO2 at 950–1400 K. Rapid and uniform heating was observed for 8 ppi ceria RPC with mm‐sized porosity due to its low optical thickness and volumetric radiative absorption, while ceria fibers with μm‐sized porosity performed poorly due to its opacity to incident irradiation. The 10 ppi RPC exhibited higher fuel yield because of its higher sample density. Zr4+‐doped ceria showed increasing reduction extents with dopant concentration but decreasing specific CO yield due to unfavorable oxidation thermodynamics and slower kinetics. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1263–1271, 2017 PMID:28405030

  20. Effect of biodegradation on thermogravimetric and chemical characteristics of hardwood and softwood by brown-rot fungus.

    Science.gov (United States)

    Gao, Zhenzhong; Fan, Qi; He, Zesen; Wang, Zhinan; Wang, Xiaobo; Sun, Jin

    2016-07-01

    The thermogravimetric and chemical characterization of hardwood Eucalyptus urophylla (Ep) and softwood Pinus massoniana (Mp) pretreated by brown-rot fungus Gloeophyllum trabeum were investigated. The results indicated that the brown-rot fungus pretreatment can optimize the thermal decomposition and decrease the initiation temperatures (8-11°C lower) of both the Ep and Mp pyrolysis. The mean activation energy values of the bio-treated samples were 29.7kJ/mol (for Ep) and 42.3kJ/mol (for Mp) lower than that of the un-treated samples at the conversion rate from 0.1 to 0.7 based on Flynn-Wall-Ozawa (FWO) method. After the bio-pretreatment, the required temperatures were lower (4-7°C) for the pyrolysis rates of hemicellulose and cellulose in Mp reaching maximum and termination. However, the situation was just the opposite for Ep. The variations in chemical properties of hydrogen bonding, as well as the relative changes in lignin/carbohydrate composition of both wood species were also examined. Copyright © 2016 Elsevier Ltd. All rights reserved.