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Sample records for calorimetry dsc experimental

  1. Influência de alguns parâmetros experimentais nos resultados de análises calorimétricas diferenciais - DSC Influence of some experimental parameters on the results of differential scanning calorimetry - DSC.

    Directory of Open Access Journals (Sweden)

    Cláudia Bernal

    2002-09-01

    Full Text Available A series of experiments were performed in order to demonstrate to undergraduate students or users of the differential scanning calorimetry (DSC, that several factors can influence the qualitative and quantitative aspects of DSC results. Saccharin, an artificial sweetner, was used as a probe and its thermal behavior is also discussed on the basis of thermogravimetric (TG and DSC curves.

  2. Differential scanning calorimetry (DSC) of ThO2

    International Nuclear Information System (INIS)

    In view of vast resources of thorium in the country, its utilisation has been identified as a key element in our country's nuclear energy programme to meet the long time energy security. As a part of a comprehensive programme undertaken for investigating the physico-chemical properties of thorium and its compounds, thermal studies have been carried out employing differential scanning calorimetry (DSC) to measure the heat capacity of ThO2. A number of parameters have been investigated to arrive at the optimum conditions for this measurement

  3. Determination of Purity by Differential Scanning Calorimetry (DSC).

    Science.gov (United States)

    Brown, M. E.

    1979-01-01

    An exercise is presented which demonstrates the determination of sample purity by differential scanning calorimetry. Data and references are provided to enable the exercise to be carried out as a dry-lab experiment. (BB)

  4. Nucleation and crystallisation kinetics of a Na-fluorrichterite based glass by differential scanning calorimetry (DSC)

    OpenAIRE

    Pérez, Juan M.; Casasola, Raquel; Rincón López, Jesús María; Romero, Maximina

    2012-01-01

    The present paper shows the results of a nucleation and crystallisation study of a Na-fluorrichterite glass carried out by dynamic scanning calorimetry (DSC). The kinetic study was performed using different procedures (Kissinger, Matusita–Sakka and Kissinger–Akahira–Sunose (KAS) methods), and the Avrami parameter was determined from the Ozawa and Malek approximations and the Malek equation. The results have indicated the coexistence of surface and bulk crystallisation in the devitrification p...

  5. Recent advances and potential applications of modulated differential scanning calorimetry (mDSC) in drug development.

    Science.gov (United States)

    Knopp, Matthias Manne; Löbmann, Korbinian; Elder, David P; Rades, Thomas; Holm, René

    2016-05-25

    Differential scanning calorimetry (DSC) is frequently the thermal analysis technique of choice within preformulation and formulation sciences because of its ability to provide detailed information about both the physical and energetic properties of a substance and/or formulation. However, conventional DSC has shortcomings with respect to weak transitions and overlapping events, which could be solved by the use of the more sophisticated modulated DSC (mDSC). mDSC has multiple potential applications within the pharmaceutical field and the present review provides an up-to-date overview of these applications. It is aimed to serve as a broad introduction to newcomers, and also as a valuable reference for those already practising in the field. Complex mDSC was introduced more than two decades ago and has been an important tool for the quantification of amorphous materials and development of freeze-dried formulations. However, as discussed in the present review, a number of other potential applications could also be relevant for the pharmaceutical scientist. PMID:26721421

  6. Evaluation of peritoneal tissue by means of differential scanning calorimetry (DSC

    Directory of Open Access Journals (Sweden)

    Łukasz Pietrzyk

    2012-01-01

    Full Text Available Abdominal surgeries alter the integrity of the peritoneal layer and cause imbalances among immunological, inflammatory and angiogenic mechanisms within the tissue. During laparoscopic procedures a protective function of the peritoneal layer can be disturbed by the gas used to create a pneumoperitoneum. The aim of this study was to characterize peritoneal tissue by means of differential scanning calorimetry (DSC as a reference for future investigations on the influence of surgical procedures on the physicochemical state of the peritoneum. Thirty-seven patients participated in the study. Patients were divided into three groups according to the type of surgery: group H — patients who underwent hernia repair; group Ch — patients who underwent laparoscopic cholecystectomy; and group C — patients operated due to rectal cancer. It was observed that onset temperature (To, denaturation temperature (Tm and change of enthalpy (ΔH during thermal denaturation of peritoneal collagen in were significantly different for these three groups of patients. The mean values of onset temperature (To and denaturation temperature (Tm in group H were significantly lower, while DH in this group was significantly higher than in the two other groups (Ch and C. This preliminary study does not answer whether the differences in collagen denaturation found in peritoneal tissue from different groups of patients resulted from a different inherent state of the tissue, or from surgical procedures. However, the results suggest that DSC is an appropriate method to study subtle changes in the physicochemical condition of the peritoneum using small samples obtained during surgical procedures. (Folia Histochemica et Cytobiologica 2011; Vol. 49, No. 4, pp. 700–705

  7. Combustion calorimetry experimental chemical thermodynamics

    CERN Document Server

    Sunner, Stig

    1979-01-01

    Combustion Calorimetry deals with expertise knowledge concerning the calorimetry of combustion reactions of an element or compound. After defining the use of units and physical constants, the book discusses the basic principles of combustion calorimetry and the various instruments and calorimeters used in the experiments to measure operations concerning temperatures and its time variations. One paper discusses the theory and design criteria of combustion calorimeter calibration. Another paper discusses the results obtained from a combustion calorimeter after it has measured the energy or entha

  8. Application of Differential Scanning Calorimetry (DSC in study of phase transformations in ductile iron

    Directory of Open Access Journals (Sweden)

    R. Przeliorz

    2010-04-01

    Full Text Available The effect of heating rate on phase transformations to austenite range in ductile iron of the EN-GJS-450-10 grade was investigated. For studies of phase transformations, the technique of differential scanning calorimetry (DSC was used. Microstructure was examined by optical microscopy. The calorimetric examinations have proved that on heating three transformations occur in this grade of ductile iron, viz. magnetic transformation at the Curie temperature, pearlite→austenite transformation and ferrite→austenite transformation. An increase in the heating rate shifts the pearlite→austenite and ferrite→austenite transformations to higher temperature range. At the heating rate of 5 and 15°C/min, local extrema have been observed to occur: for pearlite→austenite transformation at 784°C and 795°C, respectively, and for ferrite→austenite transformation at 805°C and 821°C, respectively. The Curie temperature of magnetic transformation was extrapolated to a value of 740°C. Each transformation is related with a specific thermal effect. The highest value of enthalpy is accompanying the ferrite→austenite transformation, the lowest occurs in the case of pearlite→austenite transformation.

  9. Effects of experimental variables in quantitative differential scanning calorimetry

    OpenAIRE

    Dooren, Adrianus August van

    1982-01-01

    Dit proefschriÍt beschrijft een onderzoek naar de effecten van experimentele omstandigheden op curve-karakteristieken en enige toepassingen van kwantitatieve Differentiele Scanning calorimetry (DSC). ... Zie: Samenvatting

  10. Characterization of a Friction Stir Weld in Aluminum Alloy 7055 Using Microhardness, Electrical Conductivity, and Differential Scanning Calorimetry (DSC)

    Science.gov (United States)

    Bush, Ralph; Kiyota, Michelle; Kiyota, Catherine

    2016-04-01

    Optical microscopy, microhardness, electrical conductivity, and differential scanning calorimetry (DSC) were used to characterize the microstructure, hardness, and precipitate structure as a function of position in a friction stir weld, naturally aged for 10 years, in aluminum alloy 7055. Results are shown for the as-welded/naturally aged condition and for a weld that was post-aged using a -T76 regimen. The grain structure and microhardness results reveal the expected central recrystallized region, a thermo-mechanical affected zone (TMAZ), and heat-affected zone (HAZ) with typical changes in microhardness. DSC scans for the as-welded/naturally aged condition indicate a precipitate structure similar to that of a naturally aged condition in the central recrystallized region. Maximum precipitate coarsening and overaging occurs near the TMAZ/HAZ boundary with reduced precipitate dissolution and coarsening as the distance from the weld increases. The post-weld aging resulted in the transformation of GP zones to more stable precipitates plus coarsening of the more stable η' and η precipitates. A combination of DSC testing and CALPHAD calculations allowed calculation of precipitate volume fraction in the HAZ. The precipitate volume fraction decreased monotonically from 0.052 in the baseline material to 0.044 at the TMAZ/HAZ interface.

  11. Characterization of a Friction Stir Weld in Aluminum Alloy 7055 Using Microhardness, Electrical Conductivity, and Differential Scanning Calorimetry (DSC)

    Science.gov (United States)

    Bush, Ralph; Kiyota, Michelle; Kiyota, Catherine

    2016-07-01

    Optical microscopy, microhardness, electrical conductivity, and differential scanning calorimetry (DSC) were used to characterize the microstructure, hardness, and precipitate structure as a function of position in a friction stir weld, naturally aged for 10 years, in aluminum alloy 7055. Results are shown for the as-welded/naturally aged condition and for a weld that was post-aged using a -T76 regimen. The grain structure and microhardness results reveal the expected central recrystallized region, a thermo-mechanical affected zone (TMAZ), and heat-affected zone (HAZ) with typical changes in microhardness. DSC scans for the as-welded/naturally aged condition indicate a precipitate structure similar to that of a naturally aged condition in the central recrystallized region. Maximum precipitate coarsening and overaging occurs near the TMAZ/HAZ boundary with reduced precipitate dissolution and coarsening as the distance from the weld increases. The post-weld aging resulted in the transformation of GP zones to more stable precipitates plus coarsening of the more stable η' and η precipitates. A combination of DSC testing and CALPHAD calculations allowed calculation of precipitate volume fraction in the HAZ. The precipitate volume fraction decreased monotonically from 0.052 in the baseline material to 0.044 at the TMAZ/HAZ interface.

  12. Study on the characterization and thermal decomposition of uranium compounds by thermogravimetry (TG) and differential scanning calorimetry (DSC)

    International Nuclear Information System (INIS)

    A contribution to the characterization of several uranium compounds obtained at the IPEN' Uranium Pilot Plant is given. Particularly, samples of ammonium diuranate (ADU) and uranium oxides were studied. The main objective was to know the stoichiometry of the ADU and the oxides resulting from its thermal transformation. ADU samples were prepared by batchwise precipitation, stationary dewatering into stove and batchwise thermal decomposition, or, alternatively, continuous precipitation, continuous filtration, continuous drying and continuous thermal decomposition inside a temperature gradient electrical furnace. All ADU were precipitated using NH3 gas from uranul sulfate or uranyl nitrate solutions. The thermal decomposition of ADU and uranium oxides were studied in an air atmosphere by thermogravimetry (TG) and differential scanning calorimetry (DSC). Any correlation between the parameters of precipitation, drying, calcination and the hystory of the obtaintion of the several uraniumm compounds and their initial and final composition was looked for. Heating program was established to have the U3O8 oxide as the final product. Intermediary phases were tentatively identified. Temperatures at which occurred the absorption water elimination, crystallization water elimination, evolution or oxidation of NH3, decomposition of NO-3 ion and oxygen evolution and the exo- and endothermic process for each sample were identified. (Author)

  13. Estimation of hydrogen bondings in coal utilizing FTir and differential scanning calorimetry (DSC); FTir to DSC wo mochiita sekitannai suiso ketsugo no teiryoteki hyoka no kokoromi

    Energy Technology Data Exchange (ETDEWEB)

    Mae, K.; Miura, K. [Kyoto University, Kyoto (Japan). Faculty of Engineering

    1996-10-28

    With an objective to know coal condensation structure which has influence on coal conversion reaction, an attempt was made on quantitative evaluation of hydrogen bonding in coal. Using as test samples the VDC made from Taiheiyo coal swollen by tetralin and vacuum-dried, and its pyrolyzed char, DSC measurement and Fourier transform infrared spectroscopy (FT) were performed. An FT spectrum comparison revealed that the VDC swollen at 220{degree}C has the hydrogen bonding relaxed partly from the original coal. However, since the change is in a huge coal molecular structure restraining space, it has stopped at relaxation of the bonding energy without causing separation as far as free radicals. On the other hand, the DSC curve shows that the VDC has slower endothermic velocity than the original coal. In other words, the difference in heat absorption amounts in both materials is equivalent to the difference of enthalpy ({Delta} H) of both materials, which corresponds to the relaxation of the hydrogen bonding. Therefore, the {Delta} H was related to wavenumber shift of the FT spectra (which corresponds to change in the hydrogen bonding condition). By using this relationship, a method for evaluating hydrogen bonding distribution was proposed from an O-H contracting vibration change that can be measured by using the FT spectra and a thermal change that can be measured by using the DSC. 3 refs., 7 figs.

  14. Calorimetry

    International Nuclear Information System (INIS)

    An overall review of properties of various types of calorimeters is given, with special attention given to the challenges of high luminosity and high energy. The calorimeters described include continuous calorimeters, scintillation sampling calorimetry, gas sampling calorimetry, and liquid ionization calorimeters. Next explored are some limiting factors involved in experiments at high luminosities (or at high energies), and some examples are offered of detectors capable of operating at the highest luminosities (energies). Specific areas where substantial research and development work is needed are itemized

  15. Estudo termoanalítico de comprimidos revestidos contendo captopril através de termogravimetria (TG e calorimetria exploratória diferencial (DSC Thermal analysis study of captopril coated tablets by thermogravimetry (TG and differential scanning calorimetry (DSC

    Directory of Open Access Journals (Sweden)

    Giovana Carolina Bazzo

    2005-09-01

    Full Text Available No presente trabalho foram desenvolvidos comprimidos de captopril revestidos com hidroxipropilmetilcelulose (HPMC, Opadry®, polivinilpirrolidona (PVP, Eudragit® E e goma laca. Foi realizado estudo termoanalítico do fármaco e das formulações através de termogravimetria (TG e calorimetria exploratória diferencial (DSC. Através da análise das curvas DSC verificou-se que não houve a ocorrência de interação entre o fármaco e os excipientes lactose, celulose microcristalina, croscarmelose sódica, Aerosil® e talco, utilizados na formulação do comprimido. Através desta técnica detectou-se a possibilidade de interação entre captopril e estearato de magnésio. De acordo com os resultados obtidos através de DSC não foram observadas alterações na cristalinidade do fármaco decorrentes dos processos de compressão e revestimento. A termogravimetria foi utilizada para o estudo da cinética de degradação do captopril e dos comprimidos. Os parâmetros cinéticos foram determinados através do método de Ozawa. Os resultados demonstraram que não houve alteração da estabilidade térmica do captopril na forma de comprimido. A formulação revestida com HPMC foi a que apresentou maior estabilidade térmica, quando comparada às demais formulações de revestimento.In the present study, captopril coated tablets with hydroxypropylmethylcellulose (HPMC, Opadry®, polyvinylpirrolidone (PVP, Eudragit® and shellac were produced. Differential scanning calorimetry (DSC and thermogravimetry (TG were used to evaluate the thermal properties of the drug and the formulations. On the basis of DSC results, captopril was found to be compatible with lactose, microcrystalline cellulose, sodium croscarmellose, Aerosil® and talc. Some possibility of interaction between drug-excipient was observed with magnesium stearate. However, additional techniques to confirm the results obtained are needed. There was no influence of mechanical treatment (tableting

  16. Mikrokalorimetrinin Hububat Teknolojisinde Kullanım İmkanları I. Differential Scanning Calorimetry (DSC) ve Yöntemin Genel Karakteristikleri

    OpenAIRE

    Certel, Muharrem; Ertugay, Zeki

    1991-01-01

    Hububat teknolojisinde, özellikle hububat ve ürünlerinden kalite kontrollerinde, basit ve hızlı bir ölçüm tekniği ile elde edilen sonuçların çok yönlülüğü nedeniyle, mikrokalorimetri günden güne artan bir önem arz etmektedir. Differential Scanning Calorimetry (DSC), gıdalardaki karbonhidrat, protein ve yağ komponentlerinin fonksiyonel özelliklerinin karakterize edilmesi ve bunların gıda teknolojisinde, özellikle de gıda işlem mühendisliğinde amaca yönelik olarak kullanımına imkan tanıyacak gü...

  17. Kinetics of Cold-Cap Reactions for Vitrification of Nuclear Waste Glass Based on Simultaneous Differential Scanning Calorimetry - Thermogravimetry (DSC-TGA) and Evolved Gas Analysis (EGA)

    International Nuclear Information System (INIS)

    For vitrifying nuclear waste glass, the feed, a mixture of waste with glass-forming and modifying additives, is charged onto the cold cap that covers 90-100% of the melt surface. The cold cap consists of a layer of reacting molten glass floating on the surface of the melt in an all-electric, continuous glass melter. As the feed moves through the cold cap, it undergoes chemical reactions and phase transitions through which it is converted to molten glass that moves from the cold cap into the melt pool. The process involves a series of reactions that generate multiple gases and subsequent mass loss and foaming significantly influence the mass and heat transfers. The rate of glass melting, which is greatly influenced by mass and heat transfers, affects the vitrification process and the efficiency of the immobilization of nuclear waste. We studied the cold-cap reactions of a representative waste glass feed using both the simultaneous differential scanning calorimetry thermogravimetry (DSC-TGA) and the thermogravimetry coupled with gas chromatography-mass spectrometer (TGA-GC-MS) as complementary tools to perform evolved gas analysis (EGA). Analyses from DSC-TGA and EGA on the cold-cap reactions provide a key element for the development of an advanced cold-cap model. It also helps to formulate melter feeds for higher production rate

  18. Kinetics of Cold-Cap Reactions for Vitrification of Nuclear Waste Glass Based on Simultaneous Differential Scanning Calorimetry - Thermogravimetry (DSC-TGA) and Evolved Gas Analysis (EGA)

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Carmen P.; Pierce, David A.; Schweiger, Michael J.; Kruger, Albert A.; Chun, Jaehun; Hrma, Pavel R.

    2013-12-03

    For vitrifying nuclear waste glass, the feed, a mixture of waste with glass-forming and modifying additives, is charged onto the cold cap that covers 90-100% of the melt surface. The cold cap consists of a layer of reacting molten glass floating on the surface of the melt in an all-electric, continuous glass melter. As the feed moves through the cold cap, it undergoes chemical reactions and phase transitions through which it is converted to molten glass that moves from the cold cap into the melt pool. The process involves a series of reactions that generate multiple gases and subsequent mass loss and foaming significantly influence the mass and heat transfers. The rate of glass melting, which is greatly influenced by mass and heat transfers, affects the vitrification process and the efficiency of the immobilization of nuclear waste. We studied the cold-cap reactions of a representative waste glass feed using both the simultaneous differential scanning calorimetry thermogravimetry (DSC-TGA) and the thermogravimetry coupled with gas chromatography-mass spectrometer (TGA-GC-MS) as complementary tools to perform evolved gas analysis (EGA). Analyses from DSC-TGA and EGA on the cold-cap reactions provide a key element for the development of an advanced cold-cap model. It also helps to formulate melter feeds for higher production rate.

  19. Differential Scanning Calorimetry Techniques: Applications in Biology and Nanoscience

    OpenAIRE

    Gill, Pooria; Moghadam, Tahereh Tohidi; Ranjbar, Bijan

    2010-01-01

    This paper reviews the best-known differential scanning calorimetries (DSCs), such as conventional DSC, microelectromechanical systems-DSC, infrared-heated DSC, modulated-temperature DSC, gas flow-modulated DSC, parallel-nano DSC, pressure perturbation calorimetry, self-reference DSC, and high-performance DSC. Also, we describe here the most extensive applications of DSC in biology and nanoscience.

  20. Monitoring of Pentoxifylline Thermal Behavior by Novel Simultaneous Laboratory Small and Wide X-Ray Scattering (SWAXS) and Differential Scanning Calorimetry (DSC).

    Science.gov (United States)

    Hodzic, Aden; Kriechbaum, Manfred; Schrank, Simone; Reiter, Franz

    2016-01-01

    The thermal and structural evolutions associated to active pharmaceutical ingredient (API) purity are monitored using a laboratory instrument (S3-MicroCaliX) allowing simultaneous time-resolved X-ray scattering at both wide and small angles (SWAXS) as a function of temperature. This is performed simultaneously with differential scanning calorimetric (DSC) that is carried out in the same apparatus at scanning rate of 2 K/min on the same sample in the range from 20° to 200°C. We have studied simultaneous thermal and structural properties of pentoxifylline, as an active pharmaceutical ingredient (API), for its purity quality control. We have found a satisfying API purity, due to obtained melting temperature and enthalpy values, which are in a well agreement with literature. We have also found that the combination of these techniques allows the thermal monitoring of scanning rates of 2 K/min, continuously without the need for static thermal equilibration, particularly for X-ray spectra. Hence, DSC and SWAXS allowing better identification of the structural thermal events recorded by following of the phase transitions simultaneously. This interpretation is much better possible when X-ray scattering at small and wide angles is coupled with DSC from the same sample. Hence, as a laboratory tool, the method presents a reproducible thermal and crystallographic API purity quality control of non-complex samples, as crucial information for pharmaceutical technology. PMID:27467972

  1. Monitoring of Pentoxifylline Thermal Behavior by Novel Simultaneous Laboratory Small and Wide X-Ray Scattering (SWAXS) and Differential Scanning Calorimetry (DSC)

    Science.gov (United States)

    Hodzic, Aden; Kriechbaum, Manfred; Schrank, Simone; Reiter, Franz

    2016-01-01

    The thermal and structural evolutions associated to active pharmaceutical ingredient (API) purity are monitored using a laboratory instrument (S3-MicroCaliX) allowing simultaneous time-resolved X-ray scattering at both wide and small angles (SWAXS) as a function of temperature. This is performed simultaneously with differential scanning calorimetric (DSC) that is carried out in the same apparatus at scanning rate of 2 K/min on the same sample in the range from 20° to 200°C. We have studied simultaneous thermal and structural properties of pentoxifylline, as an active pharmaceutical ingredient (API), for its purity quality control. We have found a satisfying API purity, due to obtained melting temperature and enthalpy values, which are in a well agreement with literature. We have also found that the combination of these techniques allows the thermal monitoring of scanning rates of 2 K/min, continuously without the need for static thermal equilibration, particularly for X-ray spectra. Hence, DSC and SWAXS allowing better identification of the structural thermal events recorded by following of the phase transitions simultaneously. This interpretation is much better possible when X-ray scattering at small and wide angles is coupled with DSC from the same sample. Hence, as a laboratory tool, the method presents a reproducible thermal and crystallographic API purity quality control of non-complex samples, as crucial information for pharmaceutical technology. PMID:27467972

  2. [Experimental high energy physics using electromagnetic energy calorimetry

    International Nuclear Information System (INIS)

    In the current year, the major part of the research on this contract was focussed on the construction of the DO detector, testing of production modules (as opposed to prototypes) and in actual coding of tracking software. We are contributing in two areas to the DO Project: the calorimetry, where we are involved in coordination, construction and testing of the central and end calorimeter modules, the test beam program and software development; and the central drift chamber being constructed at Stony Brook and for which we have developed the electronics, test facilities, tracking and general purpose software

  3. Evaluation of polymerization of an experimental bonding resin cured with light emitting diodes using Differential Scanning Calorimetry

    Directory of Open Access Journals (Sweden)

    Jafarzadekashi T.

    2009-08-01

    Full Text Available "nBackground and Aim: Extent of polymerization (Ep is the rate at which methacrylate C=C bonds are converted to aliphatic C-C bonds. The higher the Ep value, the better the polymerization of the polymer. If the polymer dose not polymerize sufficiently, it could have destructive effects e.g. releasing monomer, initiator, free radical or insufficient polymerization of hybrid layer. Therefore, measuring the Ep value is very important. Light-emitting diodes (LEDs are becoming increasingly popular in dental practice as they have a long life expectancy. LEDs do not generate infrared wavelength, and have a constant light output. Therefore, comparison of LED and Quartz tungsten halogen (QTH from the point of Ep is important. Differential Scanning Calorimetry (DSC is a proper tool for determining the Ep value, monitoring the process of reaction and reaction kinetics. The aim of this study was to measure the Ep value of a dental bonding containing camphorquinone/amine photoinitiator which were cured by LED and QTH using DSC. "nMaterials and Methods: In this experimental study, 2.5 mg of bonding material were placed in DSC aluminum pans. Two different light cures, LED & QTH (Coltene Company Coltolux ®75 LED Curing Light, were used in this study. The light guide was positioned at a distance of 9mm from the base of the sample chamber. Each sample was photopolymerized for 30 seconds, and the DSC curves were obtained after 100 seconds from initiation of photopolimerization of each sample, at both 23oC and 37oC. The heat of photopolymerization (DH was calculated from the area under the peak of the differential temperature curve. Five samples were used for each condition. The data was analyzed by two-way ANOVA. "nResults: There was highly significant difference between two temperatures in the experimental bonding (pvalue<0.001. Representative DSC curves showed the same kinetic behavior for LED and QTH. "nConclusion: The results revealed that the Ep generated by

  4. Experimental high energy physics using electromagnetic energy calorimetry

    International Nuclear Information System (INIS)

    The major emphasis of the work reported has been on the construction of the DO Project for the Fermilab 2 TeV anti p p collider (TeV I). DO has three major hardware systems - calorimetry, muon and central tracking. In addition, the group is involved in the Brookhaven neutrino experiment E734. The past year has seen publication of precision measurements of sin2Θ/sub w/ from elastic scattering of neutrinos from both electrons and protons. This experiment has just concluded its final data run which is expected to increase the neutrino-electron sample to 180ν/sub μ/e and 90 anti ν/sub μ/e events

  5. Experimental determination of the nucleation rates of undercooled micron-sized liquid droplets based on fast chip calorimetry

    International Nuclear Information System (INIS)

    Highlights: • Fast scanning calorimeter calibration with position dependence. • Calibration of fast scanning calorimeter during cooling. • Quantitative determination of nucleation rates by treating the undercooling as stochastic parameter - Abstract: Accurate thermal analyzes and calorimetry measurements depend on careful calibration measurements. For conventional differential scanning calorimeters (DSC) the calibration procedure is well known. The melting point of different pure metals is measured and compared with literature data to adjust the temperature reading of the calorimeter. Likewise, the measured melting enthalpies of standard reference substances serve for enthalpy calibration. Yet for fast chip calorimetry, new procedures need to be established. For the medium-area and large-area calorimeter chips, this procedure needs to be modified, because the calibration behavior depends on the position of the sample on the measurement area. Additionally, a way to calibrate the calorimeter for measurements performed during cooling will also be shown. For this second aspect, the athermal and diffusionless martensitic phase transformation of Ni49.9–Ti50.1 at% was used. The well-calibrated sensor chips are ideally suited to perform nucleation rate density analyzes based on a statistical approach. Here, the nucleation rate densities of micron-sized pure Sn droplets that had been coated with a non-catalytic coating have been determined by experimental analysis of the statistical variance of the undercooling response

  6. An experimental study of phase transformations in an Al-Zn-Mg-Zr alloy: DSC and hot microhardness and measurements

    International Nuclear Information System (INIS)

    Isothermal hot microhardness and multi-scan differential scanning calorimetry (DSC) experiments were carried out on an AlZnMgZr, 7000 series aluminum alloy to characterize the evolution and dissolution of GP zones and the formation of the η' phase. Three stages of hardness evolution with aging time were observed for aging in the 25-100 deg C temperature range corresponding to GP zone formation, simultaneous GP zone dissolution and η' formation, and η' formation and coarsening. The isothermal activation energy for the GP zone formation from hot microhardness measurements was about 0.35 eV per atom comparable with that from previous hardness measurements reported in the literature. From variable heating rate DSC scans, the activation energies for GP zone formation and dissolution were 0.75 and 0.92 eV per atom, respectively. The activation energy for η' phase formation and growth of the asquenched specimens as well as aged specimens was about 0.59 eV per atom, and the Avrami index for the transformation was inferred to be in the range 2.3-2.8 (±20%). The activation energies are discussed in terms of various diffusional processes in the Al matrix and are compared with values reported in the literature. (author). 37 refs., 3 tabs., 9 figs

  7. The use of Differential Scanning Calorimetry (DSC) to characterize phase diagrams of ionic mixtures of 1-n-butyl-3-methylimidazolium chloride and niobium chloride or zinc chloride

    International Nuclear Information System (INIS)

    The thermal behavior of the BMICl/NbCl5 and BMICl/ZnCl2 mixtures was investigated by DSC and correlated with previous studies using Raman spectroscopy. Combining both results, it was possible to built the phase diagram for these mixtures and suggest the formation of different compounds and the equilibria in the euthetic mixtures. The phase diagram of BMICl and NbCl5 mixture showed that probably only one compound is formed at XNbCl5 = 0.50 (BMINbCl6) and euthetic mixtures are present in the 0 ≤ XNbCl5 ≤ 0.50 composition range. For the BMICl and ZnCl2, four different compounds were detected: (BMI)2(ZnCl4) for XZnCl2 = 0.35; (BMI)2(Zn2Cl6); (BMI)2(Zn3Cl8) and (BMI)2(Zn4Cl10) for XZnCl2 = 0.70, and between these isoplets euthetic mixtures are formed.

  8. Experimental high energy physics using electomagnetic energy calorimetry

    International Nuclear Information System (INIS)

    This report discusses the following topics: Central Calorimeter and Installation; End Calorimeters; Calorimeter Calibration and Simulations; Central Drift Chamber Construction; Collider test of Drift Chamber Modules; Electronics and High Voltage System; Tracking Software; Liquid Argon Engineering for the SSC; SSC Experimental Facilities Development; and EMPACT, SSC Experiment Design

  9. Fast differential scanning calorimetry of liquid samples with chips

    DEFF Research Database (Denmark)

    Splinter, R.; van Herwaarden, A. W.; van Wetten, I. A.;

    2015-01-01

    Based on a modified version of standard chips for fast differential scanning calorimetry, DSC of liquid samples has been performed at temperature scan rates of up to 1000 °C/s. This paper describes experimental results with the protein lysozyme, bovine serum, and olive oil. The heating and cooling...

  10. IMPLICATIONS OF GLOBAL AND LOCAL MOBILITY IN AMORPHOUS EXCIPIENTS AS DETERMINED BY DSC AND TM DSC

    Directory of Open Access Journals (Sweden)

    Ion Dranca

    2009-12-01

    Full Text Available The paper explores the use of differential scanning calorimetry (DSC and temperature modulated differential scanning calorimetry (TM DSC to study α- and β- processes in amorphous sucrose and trehalose. The real part of the complex heat capacity is evaluated at the frequencies, f, from 5 to 20mHz. β-relaxations were studied by annealing glassy samples at different temperatures and subsequently heating at different rates in a differential scanning calorimeter.

  11. An experimental study of the (Ti-6Al-4V)-xH phase diagram using in situ synchrotron XRD and TGA/DSC techniques.

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Pei; Fang, Z. Zak; Koopman, Mark; Paramore, James D.; Chandran, K. S. Ravi; Ren, Yang; Lu, Jun

    2015-02-01

    Hydrogen has been investigated for decades as a temporary alloying element to refine the microstructure of Ti-6Al-4V, and is now being used in a novel powder metallurgy method known as "hydrogen sintering and phase transformation". Pseudo-binary phase diagrams of (Ti-6Al-4V)-xH have been studied and developed, but are not well established due to methodological limitations. In this paper, in situ studies of phase transformations during hydrogenation and dehydrogenation of (Ti-6Al-4V)-xH alloys were conducted using high-energy synchrotron X-ray diffraction (XRD), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The eutectoid phase transformation of β ↔ α + δ was observed in the (Ti-6Al-4V)-xH alloy via in situ synchrotron XRD at 211 °C with a hydrogen concentration of 37.5 at.% (measured using TGA-DSC). The relationships of hydrogen composition to partial pressure and temperature were investigated in the temperature range 450-900°C. Based on these results, a partial pseudo-binary phase diagram of (Ti-6Al-4V)-xH is proposed for hydrogen compositions up to 60 at.% in the temperature range 100-900°C. Using the data collected in real time under controlled parameters of temperature, composition and hydrogen partial pressure, this work characterizes relevant phase transformations and microstructural evolution for practical titanium-hydrogen technologies of Ti-6Al-4V.

  12. DSC Study of Collagen in Disc Disease

    OpenAIRE

    S. Skrzyński; Sionkowska, A.; A. Marciniak

    2010-01-01

    Differential scanning calorimetry (DSC) has been used to estimate the effect of disc disease on the collagen helix-coil transition and morphology for tissue extracted from patients during surgical operation. Forty discs were obtained from patients with degenerative disc disease undergoing surgery for low back pain. The patients were in the age between 20 and 70 years old. The specimens were kept wet during DSC experiment. The data allow the comparison between thermal stability of collagen ti...

  13. An experimental study of the (Ti–6Al–4V)–xH phase diagram using in situ synchrotron XRD and TGA/DSC techniques

    International Nuclear Information System (INIS)

    Hydrogen has been investigated for decades as a temporary alloying element to refine the microstructure of Ti–6Al–4V, and is now being used in a novel powder metallurgy method known as “hydrogen sintering and phase transformation”. Pseudo-binary phase diagrams of (Ti–6Al–4V)–xH have been studied and developed, but are not well established due to methodological limitations. In this paper, in situ studies of phase transformations during hydrogenation and dehydrogenation of (Ti–6Al–4V)–xH alloys were conducted using high-energy synchrotron X-ray diffraction (XRD), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The eutectoid phase transformation of β ↔ α + δ was observed in the (Ti–6Al–4V)–xH alloy via in situ synchrotron XRD at 211 °C with a hydrogen concentration of 37.5 at.% (measured using TGA–DSC). The relationships of hydrogen composition to partial pressure and temperature were investigated in the temperature range 450–900 °C. Based on these results, a partial pseudo-binary phase diagram of (Ti–6Al–4V)–xH is proposed for hydrogen compositions up to 60 at.% in the temperature range 100–900 °C. Using the data collected in real time under controlled parameters of temperature, composition and hydrogen partial pressure, this work characterizes relevant phase transformations and microstructural evolution for practical titanium–hydrogen technologies of Ti–6Al–4V

  14. Análise cinética da cura de adesivos de taninos das cascas de três espécies de Eucalyptus por calorimetria diferencial exploratória (DSC) Kinetic analysis of bark tannin adhesives from three species of Eucalyptus by differential scanning calorimetry (DSC)

    OpenAIRE

    Fábio Akira Mori; Benedito Rocha Vital; Alexandre Santos Pimenta; Paulo Fernando Trugilho; Gulab Newandram Jahm; Ricardo Marius Della Lucia

    2002-01-01

    O objetivo deste trabalho foi analisar a cinética de cura de adesivos à base de taninos de Eucalyptus grandis, Eucalyptus saligna e Eucalyptus urophylla por calorimetria diferencial exploratória (DSC), comparando-a com a cinética de cura de adesivos comerciais: fenol-formaldeído e de taninos de acácia-negra (Acacia mollissima D.Wild). Verificou-se que o adesivo de taninos de Eucalyptus urophylla apresentou os parâmetros cinéticos (energia de ativação, entalpia, temperatura de pico e ordem de ...

  15. Characterization of the Polycaprolactone Melt Crystallization: Complementary Optical Microscopy, DSC, and AFM Studies

    OpenAIRE

    Speranza, V; Sorrentino, A; F. De Santis; Pantani, R.

    2014-01-01

    The first stages of the crystallization of polycaprolactone (PCL) were studied using several techniques. The crystallization exotherms measured by differential scanning calorimetry (DSC) were analyzed and compared with results obtained by polarized optical microscopy (POM), rheology, and atomic force microscope (AFM). The experimental results suggest a strong influence of the observation scale. In particular, the AFM, even if limited on time scale, appears to be the most sensitive technique t...

  16. Electromagnetic calorimetry

    International Nuclear Information System (INIS)

    Electromagnetic calorimetry forms a key element of almost all current high energy particle physics detectors and has widespread application in related experimental fields such as nuclear physics and astro-particle physics. It will play a particularly important role in the latest generation of experiments at the CERN Large Hadron Collider (LHC), where it is expected that high energy electrons and photons will provide some of the clearest signatures for new discoveries. This article introduces the basic concepts underlying electromagnetic calorimetry and illustrates how these principles have been applied in recent and current detector designs, explaining the connection between technical choices and specific physics goals. Designs are described in sufficient detail to demonstrate the compromises that have to be made in achieving optimum performance within practical constraints. The main emphasis is on the LHC experiments, which provide outstanding examples of the state-of-the-art. Selected examples from other domains, such as nuclear physics and neutrino experiments are also considered and particular attention is given to calorimeter design studies for the proposed International Linear Collider (ILC) where the concept of Particle Flow Analysis is being used as a guiding influence in the overall detector optimization.

  17. Comportamento de cura de adesivo epoxídico contendo grupo mercaptana avaliado por espectroscopia no infravermelho (MIR/NIR e calorimetria exploratória diferencial (DSC Cure behavior of epoxy adhesive containig mercaptan group evaluated by infrared spectroscopy (MIR/NIR and differential scanning calorimetry (DSC

    Directory of Open Access Journals (Sweden)

    Hilzette P. C. Andrade

    2008-01-01

    Full Text Available No presente trabalho, a flexibilidade de um adesivo epoxídico contendo diglicidiléter de bisfenol A (DGEBA e dietilenotriamina (DETA como agente de cura foi modificada pela adição de um segundo componente contendo grupos mercaptana (CAPCURE. A adição de amianto ao adesivo contendo CAPCURE também foi avaliada. As reações entre os grupos epoxídicos e os grupos amina, assim como entre os grupos epoxídicos e os grupos mercaptana, foram estudadas nas regiões espectrais do infravermelho médio (MIR e próximo (NIR. Observou-se que o amianto não interfere nas reações de cura e que a espectroscopia FT-NIR evidencia melhor as alterações espectrométricas ocorridas durante as reações em relação à análise FT-MIR. O tempo das reações de cura foi monitorado por calorimetria exploratória diferencial (DSC, observando-se que a introdução do CAPCURE acelerou a cura da resina. A energia de ativação (Ea das reações de cura foi obtida pelos métodos de Barrett e Borchardt-Daniels. Os adesivos contendo CAPCURE mostraram Ea em torno de 30 kJ.mol-1, enquanto o adesivo DGEBA/DETA apresentou Ea de 46 kJ.mol-1, ambas calculadas pelo método de Barrett.In the present work, the flexibility of an epoxy adhesive containing diglycidylether of bisphenol-A (DGEBA and diethylenetriamine (DETA as curing agent was changed by the addition of a second component containing mercaptan groups (CAPCURE. The addition of asbestos as a filler in the adhesive containing CAPCURE was also evaluated. Epoxy-amine and epoxy-mercaptan reactions were studied in NIR and MIR spectral regions. The filler addition did not cause influence on the cure reactions and spectrometric changes of cure reactions could be better observed by FT-NIR than FT-MIR analysis. The cure reaction time was monitored by DSC experiments and it was observed that the introduction of CAPCURE accelerated the cure reaction. The activation energies (Ea of curing reactions were obtained using Barrett

  18. An experimental investigation to evaluate the heating value of palm oil waste by calorimetry. Paper no. IGEC-1-040

    International Nuclear Information System (INIS)

    A palm oil mill produces palm oil and kernel palm oil as main products and biomass residue (fiber and shell). This excess biomass residue can be used as fuel in boilers to meet energy and process heat demand in the industries. Quality of the palm oil waste (POW) is characterized by low fixed carbon and relatively high moisture content which may affect the heating value (HV). By applying the principle of calorimetry, a bomb calorimeter is utilized to evaluate the heating value of POW. From the experimental results, it is found that higher heating value (HHV) varies with the moisture content (MC) and it is observed as a function of MC. (author)

  19. Oil Analysis by Fast DSC

    OpenAIRE

    Wetten, I.A.; Van Herwaarden, A.W.; Splinter, R.; Ruth, van, S.M.

    2014-01-01

    Thermal analysis of Olive and Sunflower Oil is done by Fast DSC to evaluate its potential to replace DSC for adulteration detection. DSC measurements take hours, Fast DSC minutes. Peak temperatures of the crystallisation peak in cooling for different Olive and Sunflower Oils are both comparable to DSC, but not always distinguishable. The heating curves of Olive and Sunflower Oil show more differences. Compared to DSC, Fast DSC shows lower peak temperatures for heating curve peaks.

  20. The analysis of Al-based alloys by calorimetry: quantitative analysis of reactions and reaction kinetics

    OpenAIRE

    Starink, M.J.

    2004-01-01

    Differential scanning calorimetry (DSC) and isothermal calorimetry have been applied extensively to the analysis of light metals, especially Al based alloys. Isothermal calorimetry and differential scanning calorimetry are used for analysis of solid state reactions, such as precipitation, homogenisation, devitrivication and recrystallisation; and solid–liquid reactions, such as incipient melting and solidification, are studied by differential scanning calorimetry. In producing repeatable calo...

  1. Oil Analysis by Fast DSC

    NARCIS (Netherlands)

    Wetten, I.A.; Herwaarden, A.W.; Splinter, R.; Ruth, van S.M.

    2014-01-01

    Thermal analysis of Olive and Sunflower Oil is done by Fast DSC to evaluate its potential to replace DSC for adulteration detection. DSC measurements take hours, Fast DSC minutes. Peak temperatures of the crystallisation peak in cooling for different Olive and Sunflower Oils are both comparable to D

  2. 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

  3. Melting of Single Lipid Components in Binary Lipid Mixtures: A Comparison between FTIR Spectroscopy, DSC and Monte Carlo Simulations

    CERN Document Server

    Fidorra, M; Seeger, H M

    2007-01-01

    Monte Carlo (MC) Simulations, Differential Scanning Calorimetry (DSC) and Fourier Transform InfraRed (FTIR) spectroscopy were used to study the melting behavior of single lipid components in two-component membranes of 1,2-Dimyristoyl-D54-sn-Glycero-3-Phosphocholine (DMPC-d54) and 1,2-Distearoyl-sn-Glycero-3-Phosphocholine (DSPC). Microscopic information on the temperature dependent melting of the single lipid species could be investigated using FTIR. The microscopic behavior measured could be well described by the results from the MC simulations. These simulations also allowed to calculate heat capacity profiles as determined with DSC. These ones provide macroscopic information about melting enthalpies and entropy changes which are not accessible with FTIR. Therefore, the MC simulations allowed us to link the two different experimental approaches of FTIR and DSC.

  4. In-situ study of the thermal properties of hydrate slurry by high pressure DSC

    Energy Technology Data Exchange (ETDEWEB)

    Sari, O.; Hu, J.; Brun, F.; Erbeau, N. [Institute of Thermal Engineering, University of Applied Sciences of Western Switzerland, Yverdon-les-Bains (Switzerland); Homsy, P. [Nestec, Vevey (Switzerland); Logel, J.-C. [Axima Refrigeration, Bischheim (France)

    2008-07-01

    Knowing the enthalpy of hydrate slurry is very essential for energy balance and industrial applications. No direct measurement processes had been developed in this field in the past time. A new experimental method with special device has been developed to carry out on-line measurement of the thermal properties for hydrate slurry under dynamic conditions. With this special device, it is possible to deliver the hydrate slurry to the high pressure DSC (Differential Scanning Calorimetry) directly from the production tank or pipes. Thermal data acquisition will be performed afterwards by DSC. The investigated conditions were at pressure of 30 bar and temperature of {approx}+7 {sup o}C. The dissociation enthalpy of CO{sub 2} hydrate slurry was about 54 kJ/kg, corresponding 10.8% of solid fraction. The on-line measurement results for CO{sub 2} hydrate slurry give a good tendency to apply this phase change slurry to the industrial refrigeration process. (author)

  5. Hadron Calorimetry

    International Nuclear Information System (INIS)

    Hadron calorimetry has been a rapidly developing field in the past few decades. Perhaps not too far in the future, a realistic calorimeter will be capable of measuring the energies of all the fundamental particles with ∼1% precision. Currently, calorimeters with unprecedented complexity attest to the knowledge and experience that have been accumulated in high energy physics. In this review, we touch on fundamental concepts and explain new developments that we expect to be important in the future. In addition to describing applications in accelerator-based high energy physics, we briefly mention the use of hadron calorimeters in other fields.

  6. Modern calorimetry: going beyond tradition

    OpenAIRE

    Jeong, Y. H.

    2001-01-01

    Calorimetry has been a traditional tool for obtaining invaluable thermodynamic information of matter, the free energy. We describe recent efforts to go beyond this traditional calorimetry: After introducing dynamic heat capacity, we present the various experimental methods to measure it. Applications and future prospects are also given.

  7. Performance Evaluation of DSC Windows for Buildings

    Directory of Open Access Journals (Sweden)

    Jun-Gu Kang

    2013-01-01

    Full Text Available Interest in BIPV systems with dye-sensitized solar cells (DSCs that can replace building windows has increased for zero energy buildings. Although DSCs have lower efficiency in terms of electricity generation than silicon solar cells, they allow light transmission and application of various colors; they also have low production costs, which make them especially suitable for BIPV systems. DSC research is interdisciplinary, involving electrical, chemical, material, and metal engineering. A considerable amount of research has been conducted on increasing the electrical efficiency of DSC and their modules. However, there has not been sufficient research on building applications of DSC systems. The aim of this study is to evaluate the optical performance and thermal performance of DSC windows in buildings. For this study, DSC experimental models with different thicknesses and dye colors were manufactured, and their optical properties, such as transmittance and reflectivity, were measured by a spectrometer. The thermal and optical characteristics of double-glazed windows with DSC were analyzed with a window performance analysis program, WINDOW 6.0.

  8. Vapor pressure data for fatty acids obtained using an adaptation of the DSC technique

    International Nuclear Information System (INIS)

    Highlights: ► Vapor pressure data of fatty acids were measured by Differential Scanning Calorimetry. ► The DSC technique is especially advantageous for expensive chemicals. ► High heating rate was used for measuring the vapor pressure data. ► Antoine constants were obtained for the selected fatty acids. - Abstract: The vapor pressure data for lauric (C12:0), myristic (C14:0), palmitic (C16:0), stearic (C18:0) and oleic (C18:1) acids were obtained using Differential Scanning Calorimetry (DSC). The adjustments made in the experimental procedure included the use of a small sphere (tungsten carbide) placed over the pinhole of the crucible (diameter of 0.8 mm), making it possible to use a faster heating rate than that of the standard method and reducing the experimental time. The measurements were made in the pressure range from 1333 to 9333 Pa, using small sample quantities of fatty acids (3–5 mg) at a heating rate of 25 K min−1. The results showed the effectiveness of the technique under study, as evidenced by the low temperature deviations in relation to the data reported in the literature. The Antoine constants were fitted to the experimental data whose values are shown in Table 5.

  9. Vapor pressure data for fatty acids obtained using an adaptation of the DSC technique

    Energy Technology Data Exchange (ETDEWEB)

    Matricarde Falleiro, Rafael M. [LPT, Departamento de Processos Quimicos (DPQ), Faculdade de Engenharia Quimica, Universidade de Campinas (UNICAMP), 13083-852 Campinas - SP (Brazil); Akisawa Silva, Luciana Y. [Departamento de Ciencias Exatas e da Terra, Universidade Federal de Sao Paulo (UNIFESP), 09972-270 Diadema - SP (Brazil); Meirelles, Antonio J.A. [EXTRAE, Departamento de Engenharia de Alimentos (DEA), Faculdade de Engenharia de Alimentos, Universidade de Campinas (UNICAMP), 13083-862 Campinas - SP (Brazil); Kraehenbuehl, Maria A., E-mail: mak@feq.unicamp.br [LPT, Departamento de Processos Quimicos (DPQ), Faculdade de Engenharia Quimica, Universidade de Campinas (UNICAMP), 13083-852 Campinas - SP (Brazil)

    2012-11-10

    Highlights: Black-Right-Pointing-Pointer Vapor pressure data of fatty acids were measured by Differential Scanning Calorimetry. Black-Right-Pointing-Pointer The DSC technique is especially advantageous for expensive chemicals. Black-Right-Pointing-Pointer High heating rate was used for measuring the vapor pressure data. Black-Right-Pointing-Pointer Antoine constants were obtained for the selected fatty acids. - Abstract: The vapor pressure data for lauric (C{sub 12:0}), myristic (C{sub 14:0}), palmitic (C{sub 16:0}), stearic (C{sub 18:0}) and oleic (C{sub 18:1}) acids were obtained using Differential Scanning Calorimetry (DSC). The adjustments made in the experimental procedure included the use of a small sphere (tungsten carbide) placed over the pinhole of the crucible (diameter of 0.8 mm), making it possible to use a faster heating rate than that of the standard method and reducing the experimental time. The measurements were made in the pressure range from 1333 to 9333 Pa, using small sample quantities of fatty acids (3-5 mg) at a heating rate of 25 K min{sup -1}. The results showed the effectiveness of the technique under study, as evidenced by the low temperature deviations in relation to the data reported in the literature. The Antoine constants were fitted to the experimental data whose values are shown in Table 5.

  10. Quantum Calorimetry

    Science.gov (United States)

    Stahle, Caroline Kilbourne; McCammon, Dan; Irwin, Kent D.

    1999-01-01

    Your opponent's serve was almost perfect, but you vigorously returned it beyond his outstretched racquet to win the point. Now the tennis ball sits wedged in the chain-link fence around the court. What happened to the ball's kinetic energy? It has gone to heat the fence, of course, and you realize that if the fence were quite colder, you might be able to measure that heat and determine just how energetic your swing really was. Calorimetry has been a standard measurement technique since James Joule and Julius von Mayer independently concluded, about 150 years ago, that heat is a form of energy. But only in the past 15 years or so has calorimetry been applied, at millikelvin temperatures, to the measurement of the energy of individual photons and particles with exquisite sensitivity. In this article, we have tried to show that continuing research in low-temperature physics leads to a greater understanding of high-temperature astrophysics. Adaptations of the resulting spectrometers will be useful tool for fields of research beyond astrophysics.

  11. DSC Study on the Polyacrylonitrile Precursors for Carbon Fibers

    Institute of Scientific and Technical Information of China (English)

    Wangxi ZHANG; Musen LI

    2005-01-01

    Different polyacrylonitrile (PAN) precursor fibers that displayed various thermal properties were studied by using differential scanning calorimetry (DSC). Results showed that some commercial PAN precursor fibers displayed double separated peaks and these fibers were of high quality because of their process stability during their conversion to carbon fibers of high performance. Some fabrication processes, such as spinning, drawing, could not apparently change the DSC features of a PAN precursor fiber. It was concluded that the thermal properties of a PAN precursor fiber was mainly determined from its comonomer content type and compositions.

  12. Tritium calorimetry

    International Nuclear Information System (INIS)

    Complete text of publication follows. Future deuterium-tritium fusion experiments (like ITER) will use large amount of tritium. Therefore, it is very important to develop better tritium accountancy methods. Tritium calorimetry is used to measure the heat produced by the beta-decay of tritium. If we consider that all the decay energy is converted into thermal heat, we can calculate the tritium activity and mass from calorimetric measurements. The advantages of calorimetry are that it measures absolute activity, and the physical or chemical composition of the sample is not relevant. For example, tritiated structural components can only be measured in a non-destructive way with calorimeters. Disadvantages are: long measurement time for large sample volumes, and offline sampling. The accepted conversion factor is 0.324W/g ± 0.3%. I have started participation from ATOMKI in an EFDA-GOT program, called TRI-TOFFY (TRITium fOr Fusion Fuel cYcle), in 2010. I have spent 8 months at Tritium Laboratory Karlsruhe (TLK), Germany in 2011, and 9 months in 2012. TLK is a semi-industrial scale facility for processing tritium, the radioactive hydrogen isotope. The main tasks of TLK are fusion research (ITER) and neutrino physics (KATRIN), but also EU projects. The present site inventory is ∼ 25 g T2 (8914 TBq). There are four calorimeters are used for tritium analytics at TLK. My main work was to carry out upgrade on these devices, to deploy new modern control and data acquisition (DAQ) software, and to partly change their hardware. I worked on three calorimeters at the laboratory. The ANTECH-351 is a commercial 20 years old calorimeter. It is a power compensation type isothermal calorimeter. Useful sample volume is 1.2 dm3. This is not a sensitive device (power range is 1 mW - 5 W), mainly used for tritium shipment (from Canadian CANDU reactors) validation, but can measure tritium samples very fast: less than 8 hours. The IGC-V0.5 is a custom made heat flow calorimeter, using a

  13. Thermal analysis and safety information for metal nanopowders by DSC

    International Nuclear Information System (INIS)

    Highlights: • Metal nanopowders are common and frequently employed in industry. • Nano iron powder experimental results of To were 140–150 °C. • Safety information can benefit relevant metal powders industries. - Abstract: Metal nanopowders are common and frequently employed in industry. Iron is mostly applied in high-performance magnetic materials and pollutants treatment for groundwater. Zinc is widely used in brass, bronze, die casting metal, alloys, rubber, and paints, etc. Nonetheless, some disasters induced by metal powders are due to the lack of related safety information. In this study, we applied differential scanning calorimetry (DSC) and used thermal analysis software to evaluate the related thermal safety information, such as exothermic onset temperature (To), peak of temperature (Tp), and heat of reaction (ΔH). The nano iron powder experimental results of To were 140–150 °C, 148–158 °C, and 141–149 °C for 15 nm, 35 nm, and 65 nm, respectively. The ΔH was larger than 3900 J/g, 5000 J/g, and 3900 J/g for 15 nm, 35 nm, and 65 nm, respectively. Safety information can benefit the relevant metal powders industries for preventing accidents from occurring

  14. Thermal reactions of polyethylene with coal (TG/DSC approach)

    Czech Academy of Sciences Publication Activity Database

    Straka, Pavel; Náhunková, Jana

    2004-01-01

    Roč. 76, - (2004), s. 49-53. ISSN 1388-6150. [Conference on Thermal Analysis and Calorimetry /16./ TERMANAL 2003. Stará Lesná, 08.10.2003-10.10.2003] R&D Projects: GA AV ČR IAA2046902 Institutional research plan: CEZ:AV0Z3046908 Keywords : coal * DSC * TG Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.478, year: 2004

  15. Calorimetry of non-reacting systems

    CERN Document Server

    McCullough, John P

    2013-01-01

    Experimental Thermodynamics, Volume 1: Calorimetry of Non-Reacting Systems covers the heat capacity determinations for chemical substances in the solid, liquid, solution, and vapor states, at temperatures ranging from near the absolute zero to the highest at which calorimetry is feasible.This book is divided into 14 chapters. The first four chapters provide background information and general principles applicable to all types of calorimetry of non-reacting systems. The remaining 10 chapters deal with specific types of calorimetry. Most of the types of calorimetry treated are developed over a c

  16. Contactless Calorimetry for Levitated Samples

    Science.gov (United States)

    Lee, M. C.; Dokko, W.

    1986-01-01

    Temperature and specific heat of hot sample measured with pyrometer in proposed experimental technique. Technique intended expecially for contactless calorimetry of such materials as undercooled molten alloys, samples of which must be levitated to prevent contamination and premature crystallization. Contactless calorimetry technique enables data to be taken over entire undercooling temperature range with only one sample. Technique proves valuable in study of undercooling because difference in specific heat between undercooled-liquid and crystalline phases at same temperature provides driving force to convert metastable undercooled phase to stable crystalline phase.

  17. Cell asymmetry correction for temperature modulated differential scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Ishikiriyama, K.; Wunderlich, B. [Tennessee Univ., Knoxville, TN (United States). Dept. of Chemistry]|[Oak Ridge National Lab., TN (United States)

    1996-12-31

    The quality of measurement of heat capacity by differential scanning calorimetry (DSC) is based on strict symmetry of the twin calorimeter, which is important for temperature-modulated DSC. Heat capacities for sapphire-filled and empty aluminium calorimeters (pans) under designed cell imbalance caused by different pan-masses were measured. In addition, positive and negative signs of asymmetry were explored by analyzing the phase-shift between temperature and heat flow for sapphire and empty runs. The phase shifts change by more than 18{degree} depending on asymmetry sign. Once the asymmetry sign is determined, the asymmetry correction for modulated DSC can be made.

  18. Thermogravimetric and DSC testing of poly(lactic acid) nanocomposites

    International Nuclear Information System (INIS)

    Highlights: • The presence of nanoadditivities in PLA matrix improves thermal stability of PLA. • Shielding effect main reason for PLA thermal stability by nanofillers. • Thermal degradation suppression in UV-irradiated PLA by the removing of unstable compounds. - Abstract: Polymer nanocomposites based on poly(lactic acid), PLA, and two types of nanofillers: nanosilver and nanoclay were obtained by casting method. The thermal properties of PLA and nanocomposites have been studied by thermogravimetric analysis (TA) and differential scanning calorimetry (DSC). All samples have been UV-irradiated and the effect of photoprocess on their thermal stability has been estimated. It was found that nanoadditives and UV irradiation causes an increase of the activation energy of PLA thermal decomposition. DSC result supplies information on glass transition and crystallization/melting processes in PLA in the presence of nanosilver or nanoclay, also after exposure to UV

  19. Some Remarks on the Degree of Crystallinity Measured on DSC

    Institute of Scientific and Technical Information of China (English)

    邱高; 唐志廉; 黄南薰

    2001-01-01

    A modified mathematical model based on the melting and recrystallization of an initial distribution of melting temperatures predicts the melting behavior of polymer in differential scanning calorimetry ( DSC ), taking into account of changes in heat of fusion with melting temperature of crystal and average heat capacity of sample. It has been used to analytically prove that the crystallinity measured on a DSC diagram could not be equal to the weight percentage of crystalline state in the initial specimen. The deviation of the measured crystallinity, as observed relevant to the melting and recrystallization processes, is caused by the changes of the heat of fusion with the melting temperature of crystals, as well as the difference of heat capacities of liquld and solid state polymer. Furthermore, upper and lower limits of the deviation have been discussed.

  20. Thermal analysis of synthetic lubricating oils with DSC and TGA; Thermoanalyse synthetischer Schmieroele mit DSC und TGA

    Energy Technology Data Exchange (ETDEWEB)

    Fahl, J. [FUCHS DEA Schmierstoffe GmbH and Co. KG, Lab. Hamburg (Germany); Bruns, B. [DEA Mineraloel AG, Hamburg (Germany); Langenberg, E. [TA Instruments, Alzenau (Germany); Poetke, W. [Technische Univ. Bergakademie Freiberg (Germany)

    2001-07-01

    Thermal stability of selected lubricating oils was studied using thermoanalytical methods differential scanning calorimetry (DSC) and thermogravimetrical analysis (TGA). The ways worked out allow fast estimation of different base oils and additives especially under influence of CO{sub 2}. Based on heating curves thermal decomposition and evaporation reactions can be interpreted. Relations between chemical structure and thermal stability of synthetic lubricants result. (orig.) [German] Mit den thermoanalytischen Verfahren TGA und DSC wurden ausgewaehlte Schmieroele hinsichtlich ihrer thermischen Stabilitaet untersucht. Die erarbeiteten Methoden ermoeglichen eine schnelle Bewertung unterschiedlicher Grundoele und deren Additivierung insbesondere auch unter Einfluss von CO{sub 2}. Anhand der Aufheizkurven ist eine Interpretation thermischer Zersetzungs- und Verdampfungsreaktionen moeglich, und es ergeben sich somit Rueckschluesse der chemischen Struktur auf die thermische Stabilitaet. (orig.)

  1. The non-isothermal DSC kinetics of polyethylene tereftalate–epoxy compatible blends

    International Nuclear Information System (INIS)

    Highlights: ► The non-isothermal DSC kinetics of the reaction of DGEBA with DDS, in particular in the presence of phase separating PET, has been studied. ► The specific features in the kinetics of PET formulations in comparison to the pure system have been discussed. ► The fast pre-curing of the epoxy phase allows supposing sub-micro phase separation of PET and efficient toughening of the epoxy matrix. - Abstract: Polyethylene tereftalate has been dissolved in an epoxy resin based on diglycidyl ether of bisphenol-A, DGEBA, and the epoxy component has been cross-linked with the aid of two diamine hardeners. Two series of samples have been tested at the epoxy-amine stoichiometry applying the differential scanning calorimetry, DSC, in scanning mode. One of the series of samples was pre-cured at low temperatures with the aid of an aliphatic diamine hardener near the gel point and post-cured with diaminodiphenyl sulfone, DDS. The other series of samples contained the higher temperature hardener only. Consequently, the experimental data obtained in this study on both systems relate to the non-isothermal curing of DGEBA with DDS. The kinetics has been estimated applying preferably isoconversional (model free) methods. It has been established that the fast pre-curing allows performing a sub-micro phase separation and efficient toughening of the epoxy matrix

  2. The non-isothermal DSC kinetics of polyethylene tereftalate–epoxy compatible blends

    Energy Technology Data Exchange (ETDEWEB)

    Zvetkov, V.L., E-mail: zvetval@yahoo.com [Institute of Mechanics, Bulgarian Academy of Sciences, bl. I, Sofia 1113 (Bulgaria); Djoumaliisky, S.; Simeonova-Ivanova, E. [Institute of Mechanics, Bulgarian Academy of Sciences, bl. I, Sofia 1113 (Bulgaria)

    2013-02-10

    Highlights: ► The non-isothermal DSC kinetics of the reaction of DGEBA with DDS, in particular in the presence of phase separating PET, has been studied. ► The specific features in the kinetics of PET formulations in comparison to the pure system have been discussed. ► The fast pre-curing of the epoxy phase allows supposing sub-micro phase separation of PET and efficient toughening of the epoxy matrix. - Abstract: Polyethylene tereftalate has been dissolved in an epoxy resin based on diglycidyl ether of bisphenol-A, DGEBA, and the epoxy component has been cross-linked with the aid of two diamine hardeners. Two series of samples have been tested at the epoxy-amine stoichiometry applying the differential scanning calorimetry, DSC, in scanning mode. One of the series of samples was pre-cured at low temperatures with the aid of an aliphatic diamine hardener near the gel point and post-cured with diaminodiphenyl sulfone, DDS. The other series of samples contained the higher temperature hardener only. Consequently, the experimental data obtained in this study on both systems relate to the non-isothermal curing of DGEBA with DDS. The kinetics has been estimated applying preferably isoconversional (model free) methods. It has been established that the fast pre-curing allows performing a sub-micro phase separation and efficient toughening of the epoxy matrix.

  3. Analysis of crystallization kinetics of undercooled Fe-B hypereutectic alloy using DSC technique

    International Nuclear Information System (INIS)

    Highlights: ► Crystallization kinetics of undercooled Fe-B alloy was studied by DSC technique. ► Crystallization rate increased firstly and then was suppressed with increasing ΔT. ► Thermodynamic calculation was adopted to describe nucleation and growth rate. ► Temperature–time-transformation curve was constructed to explain experiment results. - Abstract: Crystallization kinetics of undercooled Fe-B hypereutectic alloy was researched using differential scanning calorimetry (DSC) technique. With the combination of melt-fluxing and high pure argon gas to purify and protect the melts, high undercooling up to 410 K was obtained successfully. The comparison of time dependent transformation fraction at different undercoolings has shown that the crystallization rate increased firstly with increasing ΔT until 354 K and then, the crystallization process was retarded with the further increase of ΔT. Applying quantitative thermodynamic calculation, the evolution of the nucleation and growth rates as a function of temperature was described. On this basis, the temperature–time-transformation (TTT) curve was thus constructed, which gives a reasonable explanation of the observed experimental results.

  4. Analysis of crystallization kinetics of undercooled Fe-B hypereutectic alloy using DSC technique

    Energy Technology Data Exchange (ETDEWEB)

    Yang, W., E-mail: weiyang@mail.nwpu.edu.cn [National Defence Key Discipline Laboratory of Light Alloy Processing Science and Technology, Nanchang Hangkong University, Nanchang 330063 (China); Liu, F.; Yang, G.C. [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an, Shaanxi 710072 (China); Xu, Z.F.; Wang, J.H.; Wang, Z.T. [National Defence Key Discipline Laboratory of Light Alloy Processing Science and Technology, Nanchang Hangkong University, Nanchang 330063 (China)

    2012-01-10

    Highlights: Black-Right-Pointing-Pointer Crystallization kinetics of undercooled Fe-B alloy was studied by DSC technique. Black-Right-Pointing-Pointer Crystallization rate increased firstly and then was suppressed with increasing {Delta}T. Black-Right-Pointing-Pointer Thermodynamic calculation was adopted to describe nucleation and growth rate. Black-Right-Pointing-Pointer Temperature-time-transformation curve was constructed to explain experiment results. - Abstract: Crystallization kinetics of undercooled Fe-B hypereutectic alloy was researched using differential scanning calorimetry (DSC) technique. With the combination of melt-fluxing and high pure argon gas to purify and protect the melts, high undercooling up to 410 K was obtained successfully. The comparison of time dependent transformation fraction at different undercoolings has shown that the crystallization rate increased firstly with increasing {Delta}T until 354 K and then, the crystallization process was retarded with the further increase of {Delta}T. Applying quantitative thermodynamic calculation, the evolution of the nucleation and growth rates as a function of temperature was described. On this basis, the temperature-time-transformation (TTT) curve was thus constructed, which gives a reasonable explanation of the observed experimental results.

  5. Thermal analysis on parchments I: DSC and TGA combined approach for heat damage assessment

    DEFF Research Database (Denmark)

    Fessas, D.; Signorelli, M.; Schiraldi, A.; Kennedy, C.J.; Wess, T.J.; Hassel, B.; Nielsen, Kurt

    2006-01-01

    Ancient, new and artificially aged parchments were investigated with both differential scanning calorimetry (DSC) and thermogravimetry (TGA). Criteria to define a quantitative ranking of the damage experienced by the bulk collagen of historical parchments were assessed. A damage-related correlation...

  6. Dynamic Calorimetry for Students

    Science.gov (United States)

    Kraftmakher, Yaakov

    2007-01-01

    A student experiment on dynamic calorimetry is described. Dynamic calorimetry is a powerful technique for calorimetric studies, especially at high temperatures and pressures. A low-power incandescent lamp serves as the sample. The ScienceWorkshop data-acquisition system with DataStudio software from PASCO Scientific displays the results of the…

  7. On the use of a reduced model for the simulation of melting of solutions in DSC experiments

    Energy Technology Data Exchange (ETDEWEB)

    Gibout, Stéphane, E-mail: stephane.gibout@univ-pau.fr [LaTEP-ENSGTI, Université de Pau et des Pays de l’Adour, Bâtiment d’Alembert, rue Jules Ferry, 64 075 Pau Cedex (France); Franquet, Erwin [LaTEP-ENSGTI, Université de Pau et des Pays de l’Adour, Bâtiment d’Alembert, rue Jules Ferry, 64 075 Pau Cedex (France); INRIA Bordeaux Sud Ouest, CAGIRE Team, 351 Cours de la Libération, 33 405 Talence Cedex (France); Maréchal, William; Dumas, Jean-Pierre [LaTEP-ENSGTI, Université de Pau et des Pays de l’Adour, Bâtiment d’Alembert, rue Jules Ferry, 64 075 Pau Cedex (France)

    2013-08-20

    Highlights: • Extension to binary solutions of a previous method developed for pure substances. • Thermal behavior of DSC sample can be obtained using a one-dimensional reduced model. • Thermodynamical parameters remain unchanged using this model. • In the perspective of future identification, this leads to a reduced computational time by 100 or even 1000. - Abstract: It is known that when studying the fusion of phase change materials (PCM) in differential scanning calorimetry (DSC) experiments, the geometry of the samples is not well known. Yet, some studies show that a numerical model, needing obviously to clearly define the shape of the sample, may reproduce the experimental DSC curve. In particular, such methods are currently applied to identification process based on inversion methods applied to the thermodynamical parameters governing the numerical model. Consequently, it means that if several numerical models are able to reproduce the thermal behavior of a PCM undergoing phase transition, the best one is the simplest one, that is to say the one which is the fastest to solve. Recently, we have thus shown that for pure substances PCM, a reduced model based on a spherical assumption for the shape of the sample leads to similar DSC curves that a more general model based on cylindrical shape. Clearly, if this result may be extended to other kinds of PCM, this will promote the capability of this method to be used in inversion process involved by identification process. The aim of the present paper is therefore to further study this method by considering non-pure materials, i.e. binary solution in the present case.

  8. Theory of calorimetry

    CERN Document Server

    Zielenkiewicz, Wojciech

    2004-01-01

    The purpose of this book is to give a comprehensive description of the theoretical fundamentals of calorimetry. The considerations are based on the relations deduced from the laws and general equations of heat exchange theory and steering theory.

  9. Calorimetry for the SSC

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, H.A.; Grannis, P.D.

    1984-01-01

    The activities related to calorimetry at Snowmass took place in three main areas. These were: (1) The performance criteria for SSC calorimetry, including the requirements on hermeticity, shower containment, segmentation and time resolution. The use of calorimetric means of particle identification was studied. (2) The study of triggering methods using calorimeter energy, angle and timing information. (3) A review of a wide variety of calorimeter materials for absorber and sampling, as well as several means of obtaining the readout of the energy deposits. 48 references, 10 figures, 1 table.

  10. Calorimetry for the SSC

    International Nuclear Information System (INIS)

    The activities related to calorimetry at Snowmass took place in three main areas. These were: (1) The performance criteria for SSC calorimetry, including the requirements on hermeticity, shower containment, segmentation and time resolution. The use of calorimetric means of particle identification was studied. (2) The study of triggering methods using calorimeter energy, angle and timing information. (3) A review of a wide variety of calorimeter materials for absorber and sampling, as well as several means of obtaining the readout of the energy deposits. 48 references, 10 figures, 1 table

  11. Using differential scanning calorimetry as an analytical tool for ultrafine-grained metals processed by severe plastic deformation

    OpenAIRE

    Gao, Nong; Starink, Marco J.; Langdon, Terence G.

    2009-01-01

    Differential Scanning Calorimetry (DSC) is a thermal analysis technique that measures the energy absorbed or released by a sample as a function of temperature or time. Analysis by DSC has wide applications for examining solid-state reactions and solid-liquid reactions in many different materials. Quantitative analyses of the kinetics of reactions may be assessed by reviewing the interrelation between activation energy analysis methods. In recent years, DSC has been applied in the examination ...

  12. PALS and DSC study of nanopores partially filled by hexadecane

    Science.gov (United States)

    Šauša, O.; Illeková, E.; Krištiak, J.; Berek, D.; Macová, E.

    2013-06-01

    The controlled porosity glasses (CPG) filled with various amount of hexadecane (HXD) in nanopores were studied both by the positron annihilation lifetime spectroscopy (PALS) and the differential scanning calorimetry (DSC) methods. Two types of CPG matrices were used with average pore sizes 12.6 and 22.2 nm. The PALS measurements showed, that when the process of large pores filling by HXD has started, the long o-Ps lifetime went down to HXD o-Ps lifetime about 3ns [1]. DSC measurements at partially filled nanopores showed always two crystallization peaks [2]. Their positions depended on average pore size of matrix. Third crystallization peak was identified in overfilled samples (only short o-Ps lifetimes were present) and their position in temperature scale was the same as for the bulk HXD peak. The latter peak was independent of the average pore size of matrices. This fact confirms the assumption that processes studied by PALS with the samples that contained smaller amount of HXD in CPG occured inside of nanopores of the matrix.

  13. PALS and DSC study of nanopores partially filled by hexadecane

    International Nuclear Information System (INIS)

    The controlled porosity glasses (CPG) filled with various amount of hexadecane (HXD) in nanopores were studied both by the positron annihilation lifetime spectroscopy (PALS) and the differential scanning calorimetry (DSC) methods. Two types of CPG matrices were used with average pore sizes 12.6 and 22.2 nm. The PALS measurements showed, that when the process of large pores filling by HXD has started, the long o-Ps lifetime went down to HXD o-Ps lifetime about 3ns. DSC measurements at partially filled nanopores showed always two crystallization peaks. Their positions depended on average pore size of matrix. Third crystallization peak was identified in overfilled samples (only short o-Ps lifetimes were present) and their position in temperature scale was the same as for the bulk HXD peak. The latter peak was independent of the average pore size of matrices. This fact confirms the assumption that processes studied by PALS with the samples that contained smaller amount of HXD in CPG occured inside of nanopores of the matrix.

  14. Cure Kinetics of DGEBA with Hyperbranched Poly(3-hydroxyphenyl) Phosphate as Curing Agent Studied by Non-isothermal DSC

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The cure kinetics of diglycidyl ether of bisphenol A(DGEBA) with hyperbranched poly(3-hydroxyphenyl) phosphate(HHPP) as the curing agent was investigated by means of non-isothermal differential scanning calorimetry(DSC) at various heating rates. The results were compared with the corresponding results by using 1,3-dihydroxybenzene(DHB) as a model compound. The results show that HHPP can enhance the cure reaction of DGEBA, resulting in the decrease of the peak temperature of the curing curve as well as the decrease of the activation energy because of the flexible -P-O- groups in the backbone of HHPP. However, both the activation energy of the cured polymer and the peak temperature of the curing curve are increased with DHB as a curing agent. The cure kinetics of the DGEBA/HHPP system was calculated by using the isoconversional method given by Málek. It was found that the two-parameter autocatalytic model(esták-Berggren equation) is the most adequate one to describe the cure kinetics of the studied system at various heating rates. The obtained non-isothermal DSC curves from the experimental data show the results being accordant with those theoretically calculated.

  15. Scintillator materials for calorimetry

    International Nuclear Information System (INIS)

    Requirements for fast, dense scintillator materials for calorimetry in high energy physics and approaches to satisfying these requirements are reviewed with respect to possible hosts and luminescent species. Special attention is given to cerium-activated crystals, core-valence luminescence, and glass scintillators. The present state of the art, limitations, and suggestions for possible new scintillator materials are presented

  16. Calorimetry at the SSC

    International Nuclear Information System (INIS)

    The state of the art, and our present understanding of the basic limitations in hadron calorimetry, are briefly described. The various options for SSC calorimeters are discussed, and the R and D needed for the ones that look most promising is outlined. 13 refs.; 8 figs

  17. Modulated differential scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Sauerbrunn, S.R.; Crowe, B.S.; Reading, M. [TA Instruments Inc., New Castle, DE (United States)

    1993-12-31

    Modulated DSC (MDSC){sup tm} is a new patent-pending extension to conventional DSC which provides information about the reversing and nonreversing characteristics of thermal events. This additional information aids interpretation and allows unique insights into the structure and behavior of materials. Data presented will demonstrate three uses of MDSC. First, the overlapping crystallization peak and glass transition in a bilayer film of polycarbonate and PET are separated by MDSC. Second, the glass transition and endothermic relaxation of epoxy are separated. Third, MDSC gives a direct measurement of the sample heat capacity. The ability to separate reversing and nonreversing transitions, as well as the ability to directly measure heat capacity, offers thermal analysis another tool for solving tough materials characterization problems.

  18. The effects of minor constituents on biodiesel cold flow properties: Differential scanning calorimetry (DSC) analyses

    Science.gov (United States)

    Biodiesel is an alternative diesel fuel made from vegetable oils, animal fats and other lipid feedstocks. Fuel properties and performance of biodiesel during cold weather are influenced by factors related to lipid feedstock as well as small concentrations of monoacylglycerols and other minor constit...

  19. Low-temperature phase behavior of fatty acid methyl esters by differential scanning calorimetry (DSC)

    Science.gov (United States)

    Fatty acid methyl ester (FAME) mixtures have many uses including biodiesel, lubricants, metal-working fluids, surfactants, polymers, coatings, green solvents and phase-change materials. The physical properties of a FAME mixture depends on the fatty acid concentration (FAC) profile. Some products hav...

  20. An absorbed dose to water standard for HDR 192Ir brachytherapy sources based on water calorimetry: Numerical and experimental proof-of-principle

    International Nuclear Information System (INIS)

    Water calorimetry is an established technique for absorbed dose to water measurements in external beams. In this paper, the feasibility of direct absorbed dose measurements for high dose rate (HDR) iridium-192 (192Ir) sources using water calorimetry is established. Feasibility is determined primarily by a balance between the need to obtain sufficient signal to perform a reproducible measurement, the effect of heat loss on the measured signal, and the positioning uncertainty affecting the source-detector distance. The heat conduction pattern generated in water by the Nucletron microSelectron-HDR 192Ir brachytherapy source was simulated using COMSOL MULTIPHYSICSTM software. Source heating due to radiation self-absorption was calculated using EGSnrcMP. A heat-loss correction kc was calculated as the ratio of the temperature rise under ideal conditions to temperature rise under realistic conditions. The calorimeter setup used a parallel-plate calorimeter vessel of 79 mm diameter and 1.12 mm thick front and rear glass windows located 24 mm apart. Absorbed dose was measured with two sources with nominal air kerma strengths of 38 000 and 21 000 U, at source-detector separations ranging from 24.7 to 27.6 mm and irradiation times of 36.0 to 80.0 s. The preliminary measured dose rate per unit air kerma strength of (0.502±0.007) μGy/(s U) compares well with the TG-43 derived 0.505 μGy/(s U). This work shows that combined dose uncertainties of significantly less than 5% can be achieved with only modest modifications of current water calorimetry techniques and instruments. This work forms the basis of a potential future absolute dose to water standard for HDR 192Ir brachytherapy

  1. An absorbed dose to water standard for HDR 192Ir brachytherapy sources based on water calorimetry: numerical and experimental proof-of-principle.

    Science.gov (United States)

    Sarfehnia, Arman; Stewart, Kristin; Seuntjens, Jan

    2007-12-01

    Water calorimetry is an established technique for absorbed dose to water measurements in external beams. In this paper, the feasibility of direct absorbed dose measurements for high dose rate (HDR) iridium-192 (192Ir) sources using water calorimetry is established. Feasibility is determined primarily by a balance between the need to obtain sufficient signal to perform a reproducible measurement, the effect of heat loss on the measured signal, and the positioning uncertainty affecting the source-detector distance. The heat conduction pattern generated in water by the Nucletron microSelectron-HDR 192Ir brachytherapy source was simulated using COMSOL MULTIPHYSICS software. Source heating due to radiation self-absorption was calculated using EGSnrcMP. A heat-loss correction k(c) was calculated as the ratio of the temperature rise under ideal conditions to temperature rise under realistic conditions. The calorimeter setup used a parallel-plate calorimeter vessel of 79 mm diameter and 1.12 mm thick front and rear glass windows located 24 mm apart. Absorbed dose was measured with two sources with nominal air kerma strengths of 38 000 and 21 000 U, at source-detector separations ranging from 24.7 to 27.6 mm and irradiation times of 36.0 to 80.0 s. The preliminary measured dose rate per unit air kerma strength of (0.502 +/- 0.007) microGy/(s U) compares well with the TG-43 derived 0.505 microGy/(s U). This work shows that combined dose uncertainties of significantly less than 5% can be achieved with only modest modifications of current water calorimetry techniques and instruments. This work forms the basis of a potential future absolute dose to water standard for HDR 192Ir brachytherapy. PMID:18196821

  2. Thermal Analysis (Differential Scanning Calorimetry And Thermogravimetric Analysis) Of SEBS Blends For Injection Molding

    OpenAIRE

    Juárez Varón, David; Ferrándiz Bou, Santiago; Peydro Rasero, Miguel Ángel; Sánchez Caballero, Samuel

    2013-01-01

    Thermal analysis (DSC: Differential Scanning Calorimetry and TGA: Thermogravimetric Analysis) of SEBS blends have been studied in this paper. SEBS blends were made using two transparent SEBS commercial grades with extreme hardness values. The first thermal property determined in SEBS blends was the evaluation of the thermal degradation at high temperatures (DSC). Another thermal property of the SEBS blends consists in knowing the degradation process of the blend (TGA). It should be emphasi...

  3. Application of calorimetry in evaluation of phase transformations in the selected hypoeutectic silumins

    Directory of Open Access Journals (Sweden)

    J. Szymszal

    2009-04-01

    Full Text Available The investigations of phase transformations described in this study were carried out on hypoeutectic alloys from the Al-Si during heating and cooling. The determination and analysis of characteristic temperature values from the solidification range was made by the DSC method in calorimetric investigations carried out on a high-temperature multi HTC Setaram scanning calorimeter. Applying the lever rule, the phase composition of the examined slumins was calculated and compared with the results of DSC calorimetry.

  4. Calorimetry of dehydrogenation and dangling-bond recombination in several hydrogenated amorphous silicon materials

    OpenAIRE

    Roura Grabulosa, Pere; Farjas Silva, Jordi; Rath, Chandana; Serra-Miralles, J.; Bertrán Serra, Enric; Roca I Cabarrocas, Pere

    2006-01-01

    Differential scanning calorimetry (DSC) was used to study the dehydrogenation processes that take place in three hydrogenated amorphous silicon materials: nanoparticles, polymorphous silicon, and conventional device-quality amorphous silicon. Comparison of DSC thermograms with evolved gas analysis (EGA) has led to the identification of four dehydrogenation processes arising from polymeric chains (A), SiH groups at the surfaces of internal voids (A'), SiH groups at interfaces (B), and in the b...

  5. Water calorimetry: The heat defect

    International Nuclear Information System (INIS)

    Domen developed a sealed water calorimeter at NIST to measure absorbed dose to water from ionizing radiation. This calorimeter exhibited anomalous behavior using water saturated with gas mixtures of H2O2. Using computer simulations of the radiolysis of water, the authors show that the observed behavior can be explained if, in the gas mixtures, the amount-of-substance of H2 and of O2 differed significantly from 50%. The authors also report the results of simulations for other dilute aqueous solutions that are used for water calorimetry--pure water, air-saturated water, and H2-saturated water. The production of H2O2 was measured for these aqueous solutions and compared to simulations. The results indicate that water saturated with a gas mixture containing an amount-of-substance of H2 of 50% and of O2 of 50% is suitable for water calorimetry if the water is stirred and is in contact with a gas space of similar volume. H2-saturated water does not require a gas space but O2 contamination must be guarded against. The lack of a scavenger for OH radicals in pure water means that, depending on the water purity, some pure water might require a large priming dose to remove reactive impurities. The experimental and theoretical problems associated with air-saturated water and O2-saturated water in water calorimeters are discussed

  6. Comparative study by TG and DSC Of membranes polyamide66/bentonite clay nanocomposite; Estudo comparativo por TG e DSC de membranas de nanocompositos poliamida66/argila bentonitica

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, K.M. de; Kojuch, L.R.; Araujo, E.M.; Lira, H.L., E-mail: keilamm@ig.com.b [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Unidade Academica de Engenharia de Materiais; Lima, F. [Universidade Estadual da Paraiba (UEPB), Campina Grande, PB (Brazil). Dept. de Quimica

    2010-07-01

    In this study, it was obtained membranes of nanocomposites polyamide66 with 3 and 5% bentonite clay consists of silicates in layers from the interior of Paraiba. The clay was treated with a quaternary ammonium salt in order to make it organophilic. The membranes were prepared by phase inversion technique from the nanocomposites in solution. The clays were characterized by X-ray diffraction (XRD) and thermogravimetry (TG). Also the membranes were characterized by differential scanning calorimetry (DSC) and TG. The XRD and TG confirmed the presence of salt in the clay and thermal stability of the treated clay. For DSC, it was observed that there was no change in melting temperature of the membranes of nanocomposites compared to membrane pure polyamide66. By TG, it was found that the decomposition of the membranes of polyamide66 with treated clay were higher compared with the untreated clay. (author)

  7. Isothermal Titration Calorimetry in the Student Laboratory

    Science.gov (United States)

    Wadso, Lars; Li, Yujing; Li, Xi

    2011-01-01

    Isothermal titration calorimetry (ITC) is the measurement of the heat produced by the stepwise addition of one substance to another. It is a common experimental technique, for example, in pharmaceutical science, to measure equilibrium constants and reaction enthalpies. We describe a stirring device and an injection pump that can be used with a…

  8. Calorimetry and thermal methods in catalysis

    CERN Document Server

    Auroux, Aline

    2013-01-01

    The book is about calorimetry and thermal analysis methods, alone or linked to other techniques, as applied to the characterization of catalysts, supports and adsorbents, and to the study of catalytic reactions in various domains: air and wastewater treatment, clean and renewable energies, refining of hydrocarbons, green chemistry, hydrogen production and storage. The book is intended to fill the gap between the basic thermodynamic and kinetics concepts acquired by students during their academic formation, and the use of experimental techniques such as thermal analysis and calorimetry to answ

  9. Scintillating-fibre calorimetry

    International Nuclear Information System (INIS)

    In the past decade, calorimetry based on scintillating plastic fibres as active elements was developed from a conceptual idea to a mature detector technology, which is nowadays widely applied in particle physics experiments. This development and the performance characteristics of representative calorimeters, both for the detection of electromagnetic and hadronic showers, are reviewed. We also discuss new information on shower development processes in dense matter and its application to calorimetric principles that has emerged from some very thorough studies that were performed in the framework of this development. (orig.)

  10. Thermal Analysis of Whole Bacterial Cells Exposed to Potassium Permanganate Using Differential Scanning Calorimetry: a Biphasic Dose-Dependent Response to Stress

    OpenAIRE

    Marina K. Abuladze; Victor M. Sokhadze; Emma N. Namchevadze; Kiziria, E.; Leila V. Tabatadze; Lejava, Lia V.; Sh. Gogichaishvili; Bakradze, Nugzar B.

    2009-01-01

    Differential scanning calorimetry (DSC) was applied to estimate the impact of the toxic oxidant potassium permanganate (PM) on the intracellular structural and functional alterations at whole cell level using soil bacteria Arthrobacter oxydans as a model culture. Differential scanning calorimetry (DSC) was applied in order to estimate the impact of the toxic oxidant potassium permanganate (PM) on the intracellular structural and functional alterations at the whole cell level using the soil b...

  11. DSC analysis of irradiated proteins from Crotalus durissus terrificus

    International Nuclear Information System (INIS)

    Full text: Snake bites are a serious public health problem, especially in subtropical countries. In Brazil, the serum, the only effective treatment in case of snake bites, is produced in horses which, despite the large size, have a reduced lifespan due to the high toxicity of the antigen. It is known that ionizing radiation effects - direct and indirect - can modify the molecular structure, affecting the biological properties of proteins. Ionizing radiation has been employed to attenuate the toxicity of snake venoms, aiming to generate an improved antigen with low toxicity. Two proteins, purified from Crotalus durissus terrificus (Cdt) venom were tested in this work: crotoxin and crotamine. Crotoxin, the main toxic compound of Cdt venom, is a heterodimeric protein composed of two subunits: crotapotin and phospholipase A2. Crotamine is a highly basic polypeptide (pI - 10.3), with myotoxic activity and molecular weight of 4882 Da. It is composed of 42 amino acids residues and reticulated by three disulfide bonds. This study aimed to investigate the effects of radiation on crotoxin and crotamine using Differential Scanning Calorimetry (DSC). After isolation of the toxins by chromatographic techniques, they were irradiated with 2.0 kGy from 60Co source. The thermodynamics analysis, carried out in a METTLER TOLEDO, DSC 822e calorimeter, showed that irradiation promoted changes of the calorimetric profile. These changes suggest that, although radiation induced structural modifications of the protein, denaturation was only partial, since transition states could still be detected, suggesting that some structural elements were still present after irradiation. Taken together, our data suggest that following irradiation, the molecules underwent conformational changes, and that the remaining structural elements displayed a lower enthalpy, clearly indicating that the previously described loss of toxicity of irradiated toxins can be mostly ascribed to structural changes. (author)

  12. DSC analysis of irradiated proteins from Crotalus durissus terrificus

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Karina Corleto de; Silva, Monica Nascimento da; Goncalves, Karina de Oliveira; Spencer, Patrick Jack; Nascimento, Nanci do [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Full text: Snake bites are a serious public health problem, especially in subtropical countries. In Brazil, the serum, the only effective treatment in case of snake bites, is produced in horses which, despite the large size, have a reduced lifespan due to the high toxicity of the antigen. It is known that ionizing radiation effects - direct and indirect - can modify the molecular structure, affecting the biological properties of proteins. Ionizing radiation has been employed to attenuate the toxicity of snake venoms, aiming to generate an improved antigen with low toxicity. Two proteins, purified from Crotalus durissus terrificus (Cdt) venom were tested in this work: crotoxin and crotamine. Crotoxin, the main toxic compound of Cdt venom, is a heterodimeric protein composed of two subunits: crotapotin and phospholipase A2. Crotamine is a highly basic polypeptide (pI - 10.3), with myotoxic activity and molecular weight of 4882 Da. It is composed of 42 amino acids residues and reticulated by three disulfide bonds. This study aimed to investigate the effects of radiation on crotoxin and crotamine using Differential Scanning Calorimetry (DSC). After isolation of the toxins by chromatographic techniques, they were irradiated with 2.0 kGy from {sup 60}Co source. The thermodynamics analysis, carried out in a METTLER TOLEDO, DSC 822e calorimeter, showed that irradiation promoted changes of the calorimetric profile. These changes suggest that, although radiation induced structural modifications of the protein, denaturation was only partial, since transition states could still be detected, suggesting that some structural elements were still present after irradiation. Taken together, our data suggest that following irradiation, the molecules underwent conformational changes, and that the remaining structural elements displayed a lower enthalpy, clearly indicating that the previously described loss of toxicity of irradiated toxins can be mostly ascribed to structural changes

  13. Dual-readout Calorimetry

    CERN Document Server

    Akchurin, N; Cardini, A.; Cascella, M.; Cei, F.; De Pedis, D.; Fracchia, S.; Franchino, S.; Fraternali, M.; Gaudio, G.; Genova, P.; Hauptman, J.; La Rotonda, L.; Lee, S.; Livan, M.; Meoni, E.; Moggi, A.; Pinci, D.; Policicchio, A.; Saraiva, J.G.; Sill, A.; Venturelli, T.; Wigmans, R.

    2013-01-01

    The RD52 Project at CERN is a pure instrumentation experiment whose goal is to un- derstand the fundamental limitations to hadronic energy resolution, and other aspects of energy measurement, in high energy calorimeters. We have found that dual-readout calorimetry provides heretofore unprecedented information event-by-event for energy resolution, linearity of response, ease and robustness of calibration, fidelity of data, and particle identification, including energy lost to binding energy in nuclear break-up. We believe that hadronic energy resolutions of {\\sigma}/E $\\approx$ 1 - 2% are within reach for dual-readout calorimeters, enabling for the first time comparable measurement preci- sions on electrons, photons, muons, and quarks (jets). We briefly describe our current progress and near-term future plans. Complete information on all aspects of our work is available at the RD52 website http://highenergy.phys.ttu.edu/dream/.

  14. Advances in hadron calorimetry

    International Nuclear Information System (INIS)

    This article concentrates on the recent improvements in our understanding of the fundamental aspects of hadron calorimetry: How do these devices work, what are the fundamental limitations to their performance, and how does the calorimeter performance relate to the needs of current and future experiments? The article is restricted to hadron calorimeter applications in accelerator-based experiments. Historically, the first large-scale detectors of this type were used in cosmic-ray experiments. They have found a wide application in underground experiments looking for nucleon decay, cosmic neutrinos, etc. In these experiments, the calorimeter is not only a detector but also a target and (for nucleon decay) a source. Therefore, the total instrumented mass is a very important parameter. Because of the completely different boundary conditions (low event rates, low energies, extremely rare processes), the emphasis in the development of these detectors has been on cheap, reliable technology with high signal-to-background separation capability

  15. Detection of sunflower oil in extra virgin olive oil by fast differential scanning calorimetry

    NARCIS (Netherlands)

    Wetten, I.A.; Herwaarden, A.W.; Splinter, R.; Boerrigter-Eenling, R.; Ruth, van S.M.

    2015-01-01

    Extra virgin olive oil (EVOO) is an economically valuable product, due to its high quality and premium price. Therefore it is vulnerable for adulteration by means of the addition of cheaper vegetable oils. Differential scanning calorimetry (DSC) has been suggested as a fast technique for the detecti

  16. Differential Scanning Calorimetry for Determining the Thermodynamic Properties of Selected Honeys

    OpenAIRE

    Tomaszewska-Gras Jolanta; Bakier Sławomir; Goderska Kamila; Mansfeld Krzysztof

    2015-01-01

    Thermodynamic properties of selected honeys: glass transition temperature (Tg), the change in specifi c heat capacity (ΔCp), and enthalpy (ΔH) were analysed using differential scanning calorimetry (DSC) in relation to the composition i.e. water and sugar content. Glass transition temperatures (Tg) of various types of honey differed significantly (p

  17. [DSC and FTIR study of adsorbed lysozyme on hydrophobic surface].

    Science.gov (United States)

    Lei, Zu-meng; Geng, Xin-peng; Dai, Li; Geng, Xin-du

    2008-09-01

    During a process of hen egg white lysozyme adsorption and folding on a moderately hydrophobic surface (PEG-600), the effects of salt((NH4)2SO4) concentrations, surface coverage and denaturant (guanidine hydrochloride, GuHCl) concentrations on thermal stability and the changes in the molecular conformation of adsorbed native and denatured lysozyme without aqueous solution were studied with a combination of differential scanning calorimetry (DSC) with FTIR spectroscopy. The results showed that temperature due to endothermic peaks was reduced and the disturbance increased at higher temperature with the increase in salt concentration and surface coverage of adsorbed protein. beta-Sheet and beta-Turn stucture increased while alpha-Helix structure decreased after the adsorption. The peaks corresponding to both C-C stretching frequency in 1400-1425 cm(-1) and amide I band frequency in 1650-1670 cm(-1) of adsorbed denatured lysozyme can be detected in FTIR spectra while that due to amide I band frequency of adsorbed native lysozyme almost can't be observed. Adsorption resulted in structural loss of adsorbed native lysozyme, whose performance was less stable. PMID:19093560

  18. Performance Evaluation of DSC Windows for Buildings

    OpenAIRE

    Jun-Gu Kang; Jin-Hee Kim; Jun-Tae Kim

    2013-01-01

    Interest in BIPV systems with dye-sensitized solar cells (DSCs) that can replace building windows has increased for zero energy buildings. Although DSCs have lower efficiency in terms of electricity generation than silicon solar cells, they allow light transmission and application of various colors; they also have low production costs, which make them especially suitable for BIPV systems. DSC research is interdisciplinary, involving electrical, chemical, material, and metal engineering. A con...

  19. One-step Real-time Food Quality Analysis by Simultaneous DSC-FTIR Microspectroscopy.

    Science.gov (United States)

    Lin, Shan-Yang; Lin, Chih-Cheng

    2016-01-01

    This review discusses an analytical technique that combines differential scanning calorimetry and Fourier-transform infrared (DSC-FTIR) microspectroscopy, which simulates the accelerated stability test and detects decomposition products simultaneously in real time. We show that the DSC-FTIR technique is a fast, simple and powerful analytical tool with applications in food sciences. This technique has been applied successfully to the simultaneous investigation of: encapsulated squid oil stability; the dehydration and intramolecular condensation of sweetener (aspartame); the dehydration, rehydration and solidification of trehalose; and online monitoring of the Maillard reaction for glucose (Glc)/asparagine (Asn) in the solid state. This technique delivers rapid and appropriate interpretations with food science applications. PMID:24762327

  20. DSC characterization of ion beam modifications in ion conducting PEO-salt polymers

    International Nuclear Information System (INIS)

    Ion conducting polymer films have been prepared by complexing non-conducting poly-(ethylene-oxide), PEO, with x fraction of NH4ClO4 salt. Since its electrical conductivity showed a maximum at x somewhere between 0.18 and 0.19, such polymer films having 17 and 19 wt% salt, have been chosen and irradiated by 160 MeV Ne6+ beam. The films have been investigated by differential scanning calorimetry (DSC) and ac impedance spectroscopy before and after the irradiations. Irradiation-induced shift of an endotherm in our DSC indicates a rise in the melting temperature from 54.6 oC to 57.9 oC for the 19% film. Cross-linking by the Ne-irradiation making the polymer structure more rigid can explain this as well as our other observation of a decrease in electrical conductivity

  1. Cure kinetics of epoxy matrix resin by differential scanning calorimetry

    Science.gov (United States)

    Cizmecioglu, M.; Gupta, A.

    1982-01-01

    A study was made on the cure kinetics of an epoxy neat-resin (Narmco 5208) using Differential Scanning Calorimetry (DSC). Two interrelated analytical methods were applied to dynamic DSC data for evaluating the kinetic parameters, such as activation energy, E, the order of reaction, n, and the total heat of polymerization (or crosslinking), delta H sub t. The first method was proposed by Ellerstein (1968), and uses a thorough differential-integral analysis of a single DSC curve to evaluate the kinetic parameters. The second method was proposed by Kissinger (1957), and uses multiple DSC curves obtained at various heating rates to evaluate E regardless of n. Kinetic analysis of Narmco 5208 epoxy resin showed that the reaction order, n, is substantially affected by the rate of heating; i.e., n is approximately 2 at slow scan rates but is reduced to 1.5 at higher scan rates. The activation energy, E, is not affected by the scan rate, and the average value of E is 25.6 + or - 1.8 kcal/mole.

  2. DSC analyses of static and dynamic precipitation of an Al–Mg–Si–Cu aluminum alloy

    OpenAIRE

    Manping Liu; Zhenjie Wu; Rui Yang; Jiangtao Wei; Yingda Yu; Pål C. Skaret; Hans J. Roven

    2015-01-01

    In the present investigation, both static and dynamic precipitations of an Al–Mg–Si–Cu aluminum alloy after solid-solution treatment (SST) were comparatively analyzed using differential scanning calorimetry (DSC). Dynamic aging was performed in the SST alloy through equal channel angular pressing (ECAP) at different temperatures of room temperature, 110, 170, 191 and 300 °C. For comparison, static artificial aging was conducted in the SST alloy at 191 °C with two aging times of 4 and 10 h. Th...

  3. Inhibitors of thermally induced burn incidents – characterization by microbiological procedure, electrophoresis, SEM, DSC and IR spectroscopy.

    Science.gov (United States)

    Pielesz, Anna; Machnicka, Alicja; Gawłowski, Andrzej; Fabia, Janusz; Sarna, Ewa; Biniaś, Włodzimierz

    2015-07-01

    Differential scanning calorimetry (DSC) and thermogravimetric (TGA) investigations, acetate electrophoresis (CAE), Fourier-transform infrared spectrometry (FTIR), scanning electron microscopy (SEM) analysis and microbiological procedures were all carried out after heating the samples to a temperature sufficient for simulating a burn incident. In particular, the purpose of the present study was to analyze the effect of antioxidants, such as fucoidan from brown seaweed and flame-retardant cyclic organophosphates and phosphonates, on an organic chicken skin that gets changed by a burn incident. DSC was considered to be a useful tool in assessing in vitro temperature-mediated cross-linking; an innovative analytical conclusion was obtained from the experimentation described in the paper. FTIR tests revealed that heating a dry organic chicken skin to the boiling point leads to the disappearance of a wide band in the 1650-1550 cm(-1) area or the conversion of a band, which may be attributed to the intermolecular β-sheet aggregates. Fucoidan from brown seaweed and flame-retardant cyclic organophosphates and phosphonates probably bind with the collagen that is changed by the burn (in addition to the influence of antioxidant solutions on samples of a blank or not boiled organic chicken skin) incident forming a polymer film with the collagen of the chicken skin surface (SEM analysis), decreasing the aggregation process and native collagen recovery. Good bacteriostatic properties were determined for fucoidan samples from brown seaweed and flame-retardant cyclic organophosphates and phosphonates against the pathogenic bacteria Escherichia coli and Staphylococcus aureus. Thus, it was observed that the fucoidan incorporated into collagen films can be used as a therapeutically active biomaterial that speeds up the wound-healing process. PMID:26029873

  4. Hydration characteristics of water in radiation polymerized hema-co- ionomeric controlled drug delivery matrices: a DSC study

    International Nuclear Information System (INIS)

    The changes in the bulk (freezable) and bound (non-freezable) water contents of radiation polymerized (2-hydroxy ethyl methacrylate) (PHEMA) containing two different types of ionomers have been studied by differential scanning calorimetry (DSC). It was found that introduction of 5-10% of acrylic acid into PHEMA matrix affects mainly the bulk water content whereas introduction of sodium para styrene sulphonate affects both types of water significantly. (author)

  5. Fractional and component analysis of crude oils by the method of dynamic microdistillation. Differential scanning calorimetry coupled with thermogravimetry

    Energy Technology Data Exchange (ETDEWEB)

    Shishkin, Yu.L. [Gubkin Russian State University of Oil and Gas, Leninsky Prospect 65, 119991 Moscow (Russian Federation)

    2006-02-15

    High-resolution differential scanning calorimetry was used to accurately establish the temperature intervals of oxidation/distillation of the major components of crude oils. Some theoretical aspects of the method of dynamic microdistillation, enabling consecutive distillation (oxidation) of the main components of hydrocarbon mixtures, are discussed. The experimental TG-DSC curves show that the temperature scan of the run can be divided into six regions, of which the first belongs to simple distillation of the sample's liquid constituent (the distillate) and the others to oxidative cracking distillation of the solid (heavy) residue. The latter occur in the order paraffins+light oils, middle base oils, heavy base oils, condensed aromatics (resins) and asphaltenes. The probable oxidation mechanisms of different classes of petroleum hydrocarbons operating in different temperature regions are discussed. Full quantitative fractional and group component analysis of a number of crude oils of different chemical classes and geological age was carried out by the combined TG-DSC techniques under specially chosen experimental conditions (those of dynamic microdistillation). (author)

  6. O valor energético dos alimentos: exemplo de uma determinação experimental, usando calorimetria de combustão Food energy values: example of an experimental determination, using combustion calorimetry

    Directory of Open Access Journals (Sweden)

    Rui C. Santos

    2010-01-01

    Full Text Available The energies involved in the combustion, under atmosphere of oxygen, of breakfast cereals and dehydrate powdered whole milk samples, were determined by combustion calorimetry. This practical work, in the field of human nutrition, involved the characterization of the nutritional composition and the combustion of samples of the two foods that are part of the alimentary diet, namely, at breakfast. The obtained results allowed to assess the energy value printed in the foods labels and discuss the way those values are estimated.

  7. DSC analysis of EB-cured polyurethane-acrylate

    International Nuclear Information System (INIS)

    The gel films obtained by electron beam (EB) solid-state polymerization of urethane-acrylate prepolymers were characterized by differential scanning calorimetry (DSC). Two kinds of urethane-acrylates were synthesized by reaction of poly(butylene adipate)diol (PBAD), 4,4'-diphenylmethane diisocyanate (MDI) and 2-hydroxyethyl acrylate (HEA) for this purpose. One is a semicrystalline prepolymer (UA-251M) with a number average molecular weight (M-barn) of 3200, and the other is an amorphous one (UA-071M) with M-barn of 1450. The M-barn varied by changing M-barn of PBAD. UA-251M gel film decreased in glass transition temperature (Tg) and increased in heat capacity change (ΔCp) at Tg with increasing irradiation dose, while the Tg and ΔCp values of UA-071M gel film changed in the opposite way to those of UA-251M gel film. Above 5 Mrad, gel fraction reached more than 90 %, and the Tg and ΔCp values changed steeply for both prepolymers. This steep change in Tg and ΔCp was attributed to the crosslinking of PBAD chains as well as of terminal acryloyl groups. Since the Tg change of UA-071M gel film depends merely on the crosslinking, the crosslinking structure was evaluated using two equations which relate the shift in Tg to crosslinking. The molecular weight between crosslinking junctions was found to be larger than the M-barn of the prepolymer. The crosslinking by the EB polymerization restricted the mobility of the polymer chain less strongly than the crosslinking by the three-functional isocyanate and α,ω-dihydroxy(polypropylene oxide) with a molecular weight of 1000 did. (author)

  8. DSC analysis of EB-cured polyurethane-acrylate

    Energy Technology Data Exchange (ETDEWEB)

    Ando, Masayuki; Uryu, Toshiyuki

    1987-10-01

    The gel films obtained by electron beam (EB) solid-state polymerization of urethane-acrylate prepolymers were characterized by differential scanning calorimetry (DSC). Two kinds of urethane-acrylates were synthesized by reaction of poly(butylene adipate)diol (PBAD), 4,4'-diphenylmethane diisocyanate (MDI) and 2-hydroxyethyl acrylate (HEA) for this purpose. One is a semicrystalline prepolymer (UA-251M) with a number average molecular weight (M-bar/sub n/) of 3200, and the other is an amorphous one (UA-071M) with M-bar/sub n/ of 1450. The M-bar/sub n/ varied by changing M-bar/sub n/ of PBAD. UA-251M gel film decreased in glass transition temperature (T/sub g/) and increased in heat capacity change (..delta..C/sub p/) at T/sub g/ with increasing irradiation dose, while the T/sub g/ and ..delta..C/sub p/ values of UA-071M gel film changed in the opposite way to those of UA-251M gel film. Above 5 Mrad, gel fraction reached more than 90 %, and the T/sub g/ and ..delta..C/sub p/ values changed steeply for both prepolymers. This steep change in T/sub g/ and ..delta..C/sub p/ was attributed to the crosslinking of PBAD chains as well as of terminal acryloyl groups. Since the T/sub g/ change of UA-071M gel film depends merely on the crosslinking, the crosslinking structure was evaluated using two equations which relate the shift in T/sub g/ to crosslinking. The molecular weight between crosslinking junctions was found to be larger than the M-bar/sub n/ of the prepolymer. The crosslinking by the EB polymerization restricted the mobility of the polymer chain less strongly than the crosslinking by the three-functional isocyanate and ..cap alpha..,..omega..-dihydroxy(polypropylene oxide) with a molecular weight of 1000 did.

  9. Performance of particle flow calorimetry at CLIC

    International Nuclear Information System (INIS)

    The particle flow approach to calorimetry can provide unprecedented jet energy resolution at a future high energy collider, such as the International Linear Collider (ILC). However, the use of particle flow calorimetry at the proposed multi-TeV Compact Linear Collider (CLIC) poses a number of significant new challenges. At higher jet energies, detector occupancies increase, and it becomes increasingly difficult to resolve energy deposits from individual particles. The experimental conditions at CLIC are also significantly more challenging than those at previous electron–positron colliders, with increased levels of beam-induced backgrounds combined with a bunch spacing of only 0.5 ns. This paper describes the modifications made to the PandoraPFA particle flow algorithm to improve the jet energy reconstruction for jet energies above 250 GeV. It then introduces a combination of timing and pT cuts that can be applied to reconstructed particles in order to significantly reduce the background. A systematic study is performed to understand the dependence of the jet energy resolution on the jet energy and angle, and the physics performance is assessed via a study of the energy and mass resolution of W and Z particles in the presence of background at CLIC. Finally, the missing transverse momentum resolution is presented, and the fake missing momentum is quantified. The results presented in this paper demonstrate that high granularity particle flow calorimetry leads to a robust and high resolution reconstruction of jet energies and di-jet masses at CLIC.

  10. Heat capacity and transition behavior of sucrose by standard, fast scanning and temperature-modulated calorimetry

    International Nuclear Information System (INIS)

    Highlights: • Experimental, apparent heat capacity of sucrose was investigated by advanced thermal analysis. • Vibrational heat capacity of solid state was linked with a low temperature experimental heat capacity of sucrose. • Equilibrium melting parameters of sucrose were determined. • Decomposition, superheating of crystalline sucrose during melting process were presented. • TGA, DSC, TMDSC, and FSC are useful tools for characterization of sucrose. - Abstract: The heat capacity (Cp) of crystalline and amorphous sucrose was determined using standard and quasi-isothermal temperature modulated differential scanning calorimetry. The results were combined with the published data determined by adiabatic calorimetry, and the Cp values are now reported for the wide 5–600 K range. The experimental Cp of solid sucrose at 5–300 K was used to calculate the vibrational, solid Cp based on the vibrational molecular motions. The calculated solid and liquid Cp together with the transition parameters for equilibrium conditions were used as references for detailed quantitative thermal analysis of crystalline and amorphous sucrose. Melting temperature (Tm) of the crystalline sucrose was identified in a broad 442–465 K range with a heat of fusion of 40–46 J/mol determined at heating rates 0.5–20 K/min, respectively. The equilibrium Tm and heat of fusion of crystalline sucrose were estimated at zero heating rate as Tom = 424.4 K and ΔHof = 32 kJ/mol, respectively. The glass transition temperature (Tg) of amorphous sucrose was at 331 K with a change in Cp of 267 J/(mol K) as it was estimated from reversing heat capacity by quasi-isothermal TMDSC on cooling. At heating rates less than 30 K/min, thermal decomposition occurred during melting, while at extreme rate of 1000 K/s, degradation was not observed. Data obtained by fast scanning calorimetry (FSC) at 1000 K/s, showed that Tm was 483 K and Tg was 364 K. Superheating effects were observed during the melting with

  11. Heat capacity and transition behavior of sucrose by standard, fast scanning and temperature-modulated calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Magoń, A. [Department of Chemistry, University of Technology, 35-959 Rzeszów (Poland); Wurm, A.; Schick, C. [Department of Physics, University of Rostock, 18057 Rostock (Germany); Pangloli, Ph.; Zivanovic, S. [Department of Food Science and Technology, University of Tennessee, Knoxville, TN 37996 (United States); Skotnicki, M. [Department of Pharmaceutical Technology, Poznan University of Medical Sciences, 60-780 Poznań (Poland); Pyda, M., E-mail: mpyda@utk.edu [Department of Chemistry, University of Technology, 35-959 Rzeszów (Poland)

    2014-08-10

    Highlights: • Experimental, apparent heat capacity of sucrose was investigated by advanced thermal analysis. • Vibrational heat capacity of solid state was linked with a low temperature experimental heat capacity of sucrose. • Equilibrium melting parameters of sucrose were determined. • Decomposition, superheating of crystalline sucrose during melting process were presented. • TGA, DSC, TMDSC, and FSC are useful tools for characterization of sucrose. - Abstract: The heat capacity (C{sub p}) of crystalline and amorphous sucrose was determined using standard and quasi-isothermal temperature modulated differential scanning calorimetry. The results were combined with the published data determined by adiabatic calorimetry, and the C{sub p} values are now reported for the wide 5–600 K range. The experimental C{sub p} of solid sucrose at 5–300 K was used to calculate the vibrational, solid C{sub p} based on the vibrational molecular motions. The calculated solid and liquid C{sub p} together with the transition parameters for equilibrium conditions were used as references for detailed quantitative thermal analysis of crystalline and amorphous sucrose. Melting temperature (T{sub m}) of the crystalline sucrose was identified in a broad 442–465 K range with a heat of fusion of 40–46 J/mol determined at heating rates 0.5–20 K/min, respectively. The equilibrium T{sub m} and heat of fusion of crystalline sucrose were estimated at zero heating rate as T{sup o}{sub m} = 424.4 K and ΔH{sup o}{sub f} = 32 kJ/mol, respectively. The glass transition temperature (T{sub g}) of amorphous sucrose was at 331 K with a change in C{sub p} of 267 J/(mol K) as it was estimated from reversing heat capacity by quasi-isothermal TMDSC on cooling. At heating rates less than 30 K/min, thermal decomposition occurred during melting, while at extreme rate of 1000 K/s, degradation was not observed. Data obtained by fast scanning calorimetry (FSC) at 1000 K/s, showed that T{sub m} was

  12. Characterization of the phase transformations in shape-memory alloys by modulated differential scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Z.G.; Sandstroem, R. [Royal Inst. of Technol., Stockholm (Sweden). Dept. of Materials Science and Engineering

    1999-12-15

    Modulated differential scanning calorimetry (MDSC) is a recently developed calorimetric technique, which has demonstrated some significant advantages over the conventional differential scanning calorimetry (DSC). By separating the reversing quantity from the non-reversing component in the total thermal events, it provides some new information that can not be obtained from the conventional DSC. The technique has been applied to various polycrystalline and single crystalline shape-memory alloys, including Cu-Zn-Al, Cu-Al-Ni, Ti-Ni(Cu), Ni-Mn-Ga and Fe-Mn-Si, to characterize the martensitic transformations, bainitic transformation, chemical and magnetic ordering transitions, atomic reordering and other kinetic relaxation processes in the alloys. The preliminary results of the MDSC measurements are summarized and the interpretation of the MDSC results and some factors affecting the results are discussed. (orig.)

  13. Characterization of the phase transformations in shape-memory alloys by modulated differential scanning calorimetry

    International Nuclear Information System (INIS)

    Modulated differential scanning calorimetry (MDSC) is a recently developed calorimetric technique, which has demonstrated some significant advantages over the conventional differential scanning calorimetry (DSC). By separating the reversing quantity from the non-reversing component in the total thermal events, it provides some new information that can not be obtained from the conventional DSC. The technique has been applied to various polycrystalline and single crystalline shape-memory alloys, including Cu-Zn-Al, Cu-Al-Ni, Ti-Ni(Cu), Ni-Mn-Ga and Fe-Mn-Si, to characterize the martensitic transformations, bainitic transformation, chemical and magnetic ordering transitions, atomic reordering and other kinetic relaxation processes in the alloys. The preliminary results of the MDSC measurements are summarized and the interpretation of the MDSC results and some factors affecting the results are discussed. (orig.)

  14. Modulated Temperature Differential Scanning Calorimetry Theoretical and Practical Applications in Polymer Characterisation

    CERN Document Server

    Reading, Mike

    2006-01-01

    MTDSC provides a step-change increase in the power of calorimetry to characterize virtually all polymer systems including curing systems, blends and semicrystalline polymers. It enables hidden transitions to be revealed, miscibility to be accurately assessed, and phases and interfaces in complex blends to be quantified. It also enables crystallinity in complex systems to be measured and provides new insights into melting behaviour. All of this is achieved by a simple modification of conventional DSC. In 1992 a new calorimetric technique was introduced that superimposed a small modulation on top of the conventional linear temperature program typically used in differential scanning calorimetry. This was combined with a method of data analysis that enabled the sample’s response to the linear component of the temperature program to be separated from its response to the periodic component. In this way, for the first time, a signal equivalent to that of conventional DSC was obtained simultaneously with a measure ...

  15. Experimental tests of particle flow calorimetry

    International Nuclear Information System (INIS)

    Precision physics at future colliders requires highly granular calorimeters to support the Particle Flow Approach for event reconstruction. This article presents a review of about 10-15 years of R and D, mainly conducted within the CALICE collaboration, for this novel type of detector. The performance of large scale prototypes in beam tests validate the technical concept of particle flow calorimeters. The comparison of test beam data with simulation, of e.g. hadronic showers, supports full detector studies and gives deeper insight into the structure of hadronic cascades than was possible previously.

  16. Experimental Tests of Particle Flow Calorimetry

    CERN Document Server

    Sefkow, Felix; Kawagoe, Kiyotomo; Pöschl, Roman; Repond, José

    2015-01-01

    Precision physics at future colliders requires highly granular calorimeters to support the Particle Flow Approach for event reconstruction. This article presents a review of about 10 - 15 years of R\\&D, mainly conducted within the CALICE collaboration, for this novel type of detector. The performance of large scale prototypes in beam tests validate the technical concept of particle flow calorimeters. The comparison of test beam data with simulation, of e.g.\\ hadronic showers, supports full detector studies and gives deeper insight into the structure of hadronic cascades than was possible previously.

  17. Calorimetry at industrial electron accelerators

    DEFF Research Database (Denmark)

    Miller, Arne; Kovacs, A.

    Calorimetry is a convenient way to measure doses at industrial electron accelerators, where high absorbed doses (1-100 kGy) are delivered at dose rates of 102-105 Gy s-1 or even higher. Water calorimeters have been used for this purpose for several years, but recently other materials such as...

  18. Calorimetry at industrial electron accelerators

    DEFF Research Database (Denmark)

    Miller, Arne; Kovacs, A.

    1985-01-01

    Calorimetry is a convenient way to measure doses at industrial electron accelerators, where high absorbed doses (1-100 kGy) are delivered at dose rates of 102-105 Gy s-1 or even higher. Water calorimeters have been used for this purpose for several years, but recently other materials such as...

  19. Development of Particle Flow Calorimetry

    OpenAIRE

    Repond, Jose

    2011-01-01

    This talk reviews the development of imaging calorimeters for the purpose of applying Particle Flow Algorithms (PFAs) to the measurement of hadronic jets at a future lepton collider. After a short introduction, the current status of PFA developments is presented, followed by a review of the major developments in electromagnetic and hadronic calorimetry.

  20. DIFFERENTIAL SCANNING CALORIMETRY NON-ISOTHERMAL THERMOXIDATIVE STUDY OF LOW DENSITY POLYETHYLENE FORMULATED WITH LIGNIN

    OpenAIRE

    Irama Piña-Saenz; Juan Chirinos-Colina; Fredy Ysambertt-Soto; Mónica Arias-Jimenez

    2012-01-01

    The antioxidant capacity of lignin (LLN) on low density polyethylene(LDPE) was studied by means of a non-isothermal method using differential scanning calorimetry (DSC). The samples under study, obtained by formulating LDPE with LLN, were subject of heat treatment at different heating rates ( = 1, 3, 5, 7, 10, 15, 20  C / min), under oxygen atmosphere to promote the thermo-oxidation of the material. A kinetic model of isoconversional termoxidative degradation, adjusted to the Arrhenius equ...

  1. Study and characterization of ammonium diuranate and uranium trioxide by thermogravimetry and differential scanning calorimetry

    International Nuclear Information System (INIS)

    Thermogravimetry (TG), Differential Thermogravimetry (DTG) and Differential Scanning Calorimetry (DSC) were used to characterize the thermal behavior of ammonium diuranate (ADU) and uranium trioxide (UO3) produced at IPEN'S Chemical Enginnering Department. Compounds characterization was done using the molar ratios among the compounds and the oxides resulting from thermal decomposition. The TG and DTG curves registered for each sample were used for the determination of the following temperatures: - temperature of water evolution (free and crystallized water); - ammonia evolution and oxidation temperature; - ocluded ammonium nitrate decomposition temperature and - oxygen release temperature. The intermediate phases and their thermal stabilities were also identified by TG and DTG and confirmed by DSC curves, DSC curves showed also the exothermic and endothermic behavior of the processes involved. Finally, the great amount of data collected in this study can be handed as a guide by the professionals responsible for the operation of ADU,UO3 and UF4 pilot plants. (Author)

  2. Evaluation of errors in determination of DNA melting curve registered with differential scanning calorimetry

    International Nuclear Information System (INIS)

    The differential scanning calorimetry (DSC) is more sensitive than UV absorption spectrophotometry as a tool for the measurement of DNA melting curves. The advantage of DSC is a direct determination of differential melting curves (DMC) obtained without numerical differentiation. However, the difference between the helix-coil transition enthalpies of AT and GC base pairs can cause distortions in the shape of melting curve. Up to date, the errors caused by those distortions were not evaluated. In this study, a simple procedure of recalculation of a calorimetric DMC into a real DMC is developed. It demonstrates that the 'real' melting curve and differential melting curve deviate very slightly from the same two curves calculated from DSC data. The melting temperature and the temperature melting range are usually the same even if the difference in the enthalpies is several times higher than a real one

  3. Isothermal Titration Calorimetry of RNA

    OpenAIRE

    Salim, Nilshad N.; Feig, Andrew L.

    2008-01-01

    Isothermal titration calorimetry (ITC) is a fast and robust method to study the physical basis of molecular interactions. A single well-designed experiment can provide complete thermodynamic characterization of a binding reaction, including Ka, ΔG, ΔH, ΔS and reaction stoichiometry (n). Repeating the experiment at different temperatures allows determination of the heat capacity change (ΔCP) of the interaction. Modern calorimeters are sensitive enough to probe even weak biological interactions...

  4. Differential scanning calorimetry of coal

    Science.gov (United States)

    Gold, P. I.

    1978-01-01

    Differential scanning calorimetry studies performed during the first year of this project demonstrated the occurrence of exothermic reactions associated with the production of volatile matter in or near the plastic region. The temperature and magnitude of the exothermic peak were observed to be strongly affected by the heating rate, sample mass and, to a lesser extent, by sample particle size. Thermal properties also were found to be influenced by oxidation of the coal sample due to weathering effects.

  5. Assessment of interactions between four proteins and benzothiazole derivatives by DSC and CD

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, Natalia [Soft Matter and Molecular Biophysics Group, Department of Applied Physics, Faculty of Physics, Campus Vida, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Verdes, Pedro V., E-mail: pedro.vazquez@usc.e [Soft Matter and Molecular Biophysics Group, Department of Applied Physics, Faculty of Physics, Campus Vida, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Ruso, Juan M. [Soft Matter and Molecular Biophysics Group, Department of Applied Physics, Faculty of Physics, Campus Vida, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain)

    2011-03-15

    The thermal denaturation of ovalbumin, lysozyme, myoglobin and fibrinogen at different BTS concentrations have been investigated using differential scanning calorimetry (DSC) and circular dichroism (CD) spectroscopy. Thermodynamic parameters: melting temperatures (T{sub m}), calorimetric enthalpy ({Delta}H), van't Hoff enthalpy ({Delta}H{sub v}) were obtained for all the systems under study. Thermal denaturation of the four proteins was completely irreversible. Changes in the protein conformation due to the adsorption of BTS molecules have been monitored by using UV-CD spectra. Greater changes in {alpha}-helical contents correspond with the BTS higher concentrations. The lysozyme denaturation temperature increases at low concentrations BTS indicating that BTS acts as a structure stabilizer; meanwhile it acts as a destabilizer at higher concentrations in all the proteins studied. The major effect is observed in the case of myoglobin, the protein with the highest {alpha}-helical secondary structure (75%).

  6. Effect of hindered amine light stabilizers on radiation resistance of polypropylene measured by DSC

    International Nuclear Information System (INIS)

    Differential scanning calorimetry (DSC) method was applied to characterize physical properties of isotactic polypropylene modified by selected HALSs before and after irradiation. Three types of amine stabilizers were applied: two derivatives of 1,2,2,6,6-pentamethyl piperidine of low and high molecular weight (Tinuvin 765 and Tinuvin 622, respectively) and one polymeric derivative of 2,2,6,6-tetramethyl piperidine (Chimassorb 944). The results obtained show that phase transitions of polypropylene are influenced by electron beam irradiation. Crystallization temperature decreases by about 6-10 oC upon exposure to ionizing radiation. Thus, upon irradiation the additives loss partly the nucleating properties, probably due to chemical changes of HALS stabilizers (hindered amine light stabilizers) during the Denisov cycle that leads to decrease of crystallization temperature

  7. Application of rigorous nonlinear regression for the analysis of complex isothermal DSC reactivity curves

    Energy Technology Data Exchange (ETDEWEB)

    Pickard, J.M.

    1988-01-01

    Differential scanning calorimetry (DSC) provides a convenient technique for monitoring the global reactivity in real time for decomposition of a variety of secondary explosives. Thermograms for decomposition of explosives are frequently characterized by nonzero initial rates followed by additional transitions involving autocatalysis. An example of this phenomenon is illustrated for decomposition of 2,2',4,4',6,6'-hexanitroazobenzene (HNAB) at temperatures of 590 and 600K. Thermograms exhibit nonzero initial rates followed by autocatalytic transitions exhibiting maxima in the range of 250--500 s. In view of the complexity and frequency of occurrence of these types of thermograms, a computer program was devised to evaluate global rate parameters using nonlinear regression. 7 refs., 5 figs., 1 tab.

  8. DSC and curing kinetics study of epoxy grouting diluted with furfural -acetone slurry

    Science.gov (United States)

    Yin, H.; Sun, D. W.; Li, B.; Liu, Y. T.; Ran, Q. P.; Liu, J. P.

    2016-07-01

    The use of furfural-acetone slurry as active diluents of Bisphenol-A epoxy resin (DGEBA) groutings has been studied by dynamic and non-isothermal DSC for the first time. Curing kinetics study was investigated by non-isothermal differential scanning calorimetries at different heating rates. Activation enery (Ea) was calculated based on Kissinger and Ozawa Methods, and the results showed that Ea increased from 58.87 to 71.13KJ/mol after the diluents were added. The furfural-acetone epoxy matrix could cure completely at the theoretical curing temperature of 365.8K and the curing time of 139mins, which were determined by the kinetic model parameters.

  9. Assessment of interactions between four proteins and benzothiazole derivatives by DSC and CD

    International Nuclear Information System (INIS)

    The thermal denaturation of ovalbumin, lysozyme, myoglobin and fibrinogen at different BTS concentrations have been investigated using differential scanning calorimetry (DSC) and circular dichroism (CD) spectroscopy. Thermodynamic parameters: melting temperatures (Tm), calorimetric enthalpy (ΔH), van't Hoff enthalpy (ΔHv) were obtained for all the systems under study. Thermal denaturation of the four proteins was completely irreversible. Changes in the protein conformation due to the adsorption of BTS molecules have been monitored by using UV-CD spectra. Greater changes in α-helical contents correspond with the BTS higher concentrations. The lysozyme denaturation temperature increases at low concentrations BTS indicating that BTS acts as a structure stabilizer; meanwhile it acts as a destabilizer at higher concentrations in all the proteins studied. The major effect is observed in the case of myoglobin, the protein with the highest α-helical secondary structure (75%).

  10. Evaluation of the modified nanoclay effect on the vulcanization of SBR through rheometric curve and DSC

    International Nuclear Information System (INIS)

    Rubber nanocomposites with nanoclays organically modified by quaternary ammonium salts may have the curing features modified significantly, since the salts may act on the rubber cure system. The aim of this work is to evaluate the influences of an organically modified montmorillonite (OMMT) on the curing reaction of an SBR (styrene butadiene rubber) with sulfur. The SBR/OMMT nanocomposites were prepared by co-coagulating SBR latex and CloisiteR 20A aqueous suspension at different nanoclay concentrations. The OMMT effect on the sulfur curing reaction was evaluated by the rheometric curve using a rheometer type RPA (Rubber Process Analyzer) and the heat of vulcanization (ΔHv) using Differential Scanning Calorimetry (DSC). The evaluation of the clay nanolayers dispersion in the SBR matrix was accomplished by x-ray diffraction (XRD) analysis. (author)

  11. Use of DSC to detect the heterogeneity of hydrothermal stability in the polyphenol-treated collagen matrix.

    Science.gov (United States)

    Tang, H R; Covington, A D; Hancock, R A

    2003-11-01

    The hydrothermal stability of the collagen matrixes treated with plant polyphenols (tannins) depends on not only the strength of the polyphenol-collagen interactions but also the distribution uniformity of polyphenolic molecules within the collagen fibrils. Traditional methods of uniformity tests rely heavily on the expertise of workers and are thus subjective. This paper describes a differential scanning calorimetry (DSC) study of the sheepskin collagen samples treated with hydrolyzable tannins, including two commercial tannins' extracts (chestnut and valonea), two pure ellagitannins (vescalagin and castalagin), and six synthetic gallotannins (di-galloyl-ethylene glycol (DGE), tri-galloyl-glycerol, tetra-galloyl-meso-erythritol, penta-galloyl-adonitol, penta-galloyl-glucose, and hexa-galloyl-ducitol). The collagen sample without polyphenol treatment and the sample treated with DGE showed a single sharp peak in their DSC thermogram with a full peak width at half height (fwhh) of 3-4 degrees C. The samples treated with other tannins all showed multiple peak DSC profiles with the fwhh of each peak at about 3-4 degrees C. These multiple peak profiles imply that in these polyphenol-treated samples, there is a distribution of collagen molecules having different hydrothermal stability. The results have demonstrated that DSC offers an objective method to detect the stability heterogeneity of collagen matrixes in the solid state, providing a useful tool for the leather industry to evaluate the uniformity of leather tanning. PMID:14582955

  12. STRUCTURAL CHARACTERIZATION OF POLYETHYLENES BY DSC ANALYSIS AFTER CRYSTALLIZATION SEGREGATION

    Institute of Scientific and Technical Information of China (English)

    Yu Ma; Mao Xu

    2000-01-01

    The molecular structure of polyethylene (PE) samples with various comonomers including propylene, 1-butene and 1-hexene was investigated by DSC and 13C-NMR techniques. The density of the samples varies from 0.948 g/cm3 to 0.917 g/cm3, and the molecular weight determined by the GPC method is in the range of 1~2 × 105. The branch point content of the samples was determined by 13C-NMR measurements and was found to be less than 20 per 1000 C atoms along the main chain. Crystallization segregation DSC technique (CSDSC) was used to characterize the branch point distribution or the segment length distribution of PEs. The crystallization segregation was performed in a successive annealing process at decreasing temperatures. The interval of two successive annealing temperatures was 6 K, and the time length of each annealing step was 2.5 h. The CSDSC results clearly indicate that all the PE samples used, including some metallocene PEs,more or less exhibit their non-uniformity in segment length distribution, and bimodal or multimodal CSDSC curves were usually observed. For quantitative characterization of the CSDSC curves and the segment length distribution two parameters,the average melting point, TmAV, and the root-mean-square deviation of melting temperature, (ATm2AV)1/2, were proposed.TmAV is corresponding to the average segment length due to branching and (ATm2AV)1/2 gives information about the width of the segment length distribution. Experimental results show that both the degree of average melting temperature depression and the width of the distribution seem to increase with increasing the branching content and are dependent on the type of comonomers. Very good reproducibility and additivity of the CSDSC method were evidenced experimentally. It was concluded that the CSDSC technique is a sensitive and convenient method for characterizing the segment length distribution of branched polyethylenes and will be of great interest in structure-property relationship

  13. DSC analyses of static and dynamic precipitation of an Al–Mg–Si–Cu aluminum alloy

    Directory of Open Access Journals (Sweden)

    Manping Liu

    2015-04-01

    Full Text Available In the present investigation, both static and dynamic precipitations of an Al–Mg–Si–Cu aluminum alloy after solid-solution treatment (SST were comparatively analyzed using differential scanning calorimetry (DSC. Dynamic aging was performed in the SST alloy through equal channel angular pressing (ECAP at different temperatures of room temperature, 110, 170, 191 and 300 °C. For comparison, static artificial aging was conducted in the SST alloy at 191 °C with two aging times of 4 and 10 h. The DSC analyses reveal that the dynamic precipitation has occurred in the ECAPed samples, while the activation energies associated with the strengthening precipitates in the dynamic samples are considerably higher than the energies in the SST and static aged samples. The higher activation energies are probably attributed to the smaller grains and higher dislocation density developed after ECAP. The results in the present investigation allow the prediction of the type of the dynamic precipitates to influence the strength of the ultrafine grained alloy during ECAP at various temperatures.

  14. Interactions of tamoxifen with distearoyl phosphatidylcholine multilamellar vesicles: FTIR and DSC studies

    Science.gov (United States)

    Bilge, Duygu; Sahin, Ipek; Kazanci, Nadide; Severcan, Feride

    2014-09-01

    Interactions of a non-steroidal antiestrogen drug, tamoxifen (TAM), with distearoyl-sn-glycero-3-phosphatidylcholine (DSPC) multilamellar liposomes (MLVs) were investigated as a function of drug concentration (1-15 mol%) by using two noninvasive techniques, namely Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). FTIR spectroscopy results show that increasing TAM concentrations (except 1 mol%) increased the wavenumbers of the CH2 stretching modes, implying an disordering effect for DSPC MLVs both in the gel and liquid crystalline phases. The bandwidth values of the CH2 stretchings except for 1 mol% increased when TAM concentrations increased for DSPC liposomes, indicating an increase in the dynamics of liposomes. The Cdbnd O stretching and PO2- antisymmetric double bond stretching bands were analyzed to study interactions of TAM with head groups of lipids. As the concentrations of TAM increased, dehydration occurred around these functional groups in the polar part of the lipids. The DSC studies on thermal properties of DSPC lipids indicate that TAM eliminated the pre transition, shifted the main phase transition to lower temperatures and broadened the phase transition curve of the liposomes.

  15. The Heats of Dilution Calorimetry and Van't-Hoff

    CERN Document Server

    Stepanov, I A

    2000-01-01

    Earlier it has been found that there is a big difference between heats of dilution measured by calorimetry and by the Van't-Hoff equation. In the present paper a reason for that is proposed. Experimental data for dilution of benzene and n-hexane in water were used.

  16. Isothermal Titration Calorimetry Can Provide Critical Thinking Opportunities

    Science.gov (United States)

    Moore, Dale E.; Goode, David R.; Seney, Caryn S.; Boatwright, Jennifer M.

    2016-01-01

    College chemistry faculties might not have considered including isothermal titration calorimetry (ITC) in their majors' curriculum because experimental data from this instrumental method are often analyzed via automation (software). However, the software-based data analysis can be replaced with a spreadsheet-based analysis that is readily…

  17. The Heats of Dilution. Calorimetry and Van't-Hoff

    OpenAIRE

    Stepanov, I. A.

    2000-01-01

    Earlier it has been found that there is a big difference between heats of dilution measured by calorimetry and by the Van't-Hoff equation. In the present paper a reason for that is proposed. Experimental data for dilution of benzene and n-hexane in water were used.

  18. Drug–polymer interaction between glucosamine sulfate and alginate nanoparticles: FTIR, DSC and dielectric spectroscopy studies

    Science.gov (United States)

    El-Houssiny, A. S.; Ward, A. A.; Mostafa, D. M.; Abd-El-Messieh, S. L.; Abdel-Nour, K. N.; Darwish, M. M.; Khalil, W. A.

    2016-06-01

    This work involves the preparation and characterization of alginate nanoparticles (Alg NPs) as a new transdermal carrier for site particular transport of glucosamine sulfate (GS). The GS–Alg NPs were examined through transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and dielectric spectroscopy. GS–Alg NPs was efficiently prepared via ionic gelation method which generates favorable conditions for the entrapment of hydrophilic drugs. The TEM studies revealed that GS–Alg NPs are discrete and have spherical shapes. FTIR studies showed a spectral change of the characteristic absorptions bands of Alg NPs after encapsulation with GS because of the amine groups of GS and the carboxylic acid groups of Alg. The DSC data showed changes in the thermal behavior of GS–Alg NPs after the addition of GS indicating signs of main chemical interaction among the drug (GS) and the polymer (Alg). The absence of the drug melting endothermic peak within the DSC thermogram of GS–Alg NPs indicating that GS is molecularly dispersed in the NPs and not crystallize. From the dielectric study, it was found modifications within the dielectric loss (ε″) and conductivity (σ) values after the addition of GS. The ε″ and σ values of Alg NPs decreased after the addition of GS which indicated the successful encapsulation of GS within Alg NPs. Furthermore, the dielectric study indicated an increase of the activation energy and the relaxation time for the first process in the GS–Alg NPs as compared to Alg NPs. Consequently, the existing observations indicated an initiation of electrostatic interaction among the amine group of GS and carboxyl group of Alg indicating the successful encapsulation of GS inside Alg NPs which could provide favorable circumstance for the encapsulation of GS for topical management.

  19. Raman and DSC studies of fragility in tellurium-zinc oxide glass formers

    Energy Technology Data Exchange (ETDEWEB)

    Stavrou, Elissaios [Department of Physics, National Technical University of Athens (Greece); Max-Planck-Institut fuer Festkoerperforschung, Stuttgart (Germany); Kripotou, Sotiria; Raptis, Constantine [Department of Physics, National Technical University of Athens (Greece); Turrell, Sylvia [Laboratoire de Spectrochimie Infrarouge et Raman (CNRS 8516), Centre d' Etudes et de Recherches Lasers et Applications (CERLA-FR CNRS 2416), Universite de Sciences et Technologies de Lille, Villeneuve d' Ascq cedex (France); Syassen, Karl [Max-Planck-Institut fuer Festkoerperforschung, Stuttgart (Germany)

    2011-11-15

    Raman scattering and differential scanning calorimetry (DSC) measurements have been carried out in four mixed (TeO{sub 2}){sub 1-x}(ZnO){sub x} (x = 0.1, 0.2, 0.3, 0.4) glasses at high temperatures (Raman and DSC through the glass transition) and high pressures (Raman) with the aim of determining the fragility of these glass forming oxides. Four different criteria, corresponding to four parameters, were applied to assess the fragility of the glasses. From the DSC studies, we have obtained the fragility parameter m which corresponds to the slopes of Arrhenius (lnQ vs. 1/T{sub g}, were Q is the heating rate) plots, and the glass transition width {delta}T{sub g}. Also, from the low-frequency Raman scattering, and in particular the boson peak intensity of the glasses at T{sub g}, we have estimated the fragility ratio r{sub R} (T{sub g}) = I{sub min}/I{sub max} whose value serves as another (empirical) fragility criterion. Finally, from high pressure Raman measurements on the glasses, we have estimated the Grueneisen parameter {gamma}{sub T} for each glass, which constitutes the fourth fragility parameter adopted in this work. Considering the four parameters {delta}T{sub g}, m, r (T{sub g}) and {gamma}{sub T} and the generally accepted (empirical) fragility criteria, we conclude that the mixed tellurium-zinc oxides constitute strong-to-intermediate glass formers (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. A Guide to Differential Scanning Calorimetry of Membrane and Soluble Proteins in Detergents.

    Science.gov (United States)

    Yang, Zhengrong; Brouillette, Christie G

    2016-01-01

    Differential scanning calorimetry (DSC) detects protein thermal unfolding by directly measuring the heat absorbed. Simple DSC experiments that require relatively small amounts of pure material can provide a wealth of information related to structure, especially with respect to domain architecture, without the need for a complete thermodynamic analysis. Thus, DSC is an ideal additional tool for membrane protein characterization and also offers several advantages over indirect thermal unfolding methods. Integral membrane proteins (IMPs) that comprise both large multitopic transmembrane domains (TMDs) and extramembranous domains (EMDs) are differentially affected by detergent interactions with both domains. In fact, in some cases, destabilization of the EMD by detergent may dominate overall IMP stability. This chapter will (1) provide a perspective on the advantages of DSC for membrane protein characterization and stability measurements, including numerous examples spanning decades of research; (2) introduce models for the interaction and destabilization of IMPs by detergents; (3) discuss two case studies from the authors' lab; and (4) offer practical advice for performing DSC in the presence of detergents. PMID:26794360

  1. Theoretical Aspects of Differential Scanning Calorimetry as a Tool for the Studies of Equilibrium Thermodynamics in Pharmaceutical Solid Phase Transitions.

    Science.gov (United States)

    Faroongsarng, Damrongsak

    2016-06-01

    Although differential scanning calorimetry (DSC) is a non-equilibrium technique, it has been used to gain energetic information that involves phase equilibria. DSC has been widely used to characterize the equilibrium melting parameters of small organic pharmaceutical compounds. An understanding of how DSC measures an equilibrium event could make for a better interpretation of the results. The aim of this mini-review was to provide a theoretical insight into the DSC measurement to obtain the equilibrium thermodynamics of a phase transition especially the melting process. It was demonstrated that the heat quantity obtained from the DSC thermogram (ΔH) was related to the thermodynamic enthalpy of the phase transition (ΔH (P) ) via: ΔH = ΔH (P) /(1 + K (- 1)) where K was the equilibrium constant. In melting, the solid and liquefied phases presumably coexist resulting in a null Gibbs free energy that produces an infinitely larger K. Thus, ΔH could be interpreted as ΔH (P). Issues of DSC investigations on melting behavior of crystalline solids including polymorphism, degradation impurity due to heating in situ, and eutectic melting were discussed. In addition, DSC has been a tool for determination of the impurity based on an ideal solution of the melt that is one of the official methods used to establish the reference standard. PMID:27091667

  2. Development of a certified reference material for calibration of DSC and DTA below room temperature: NMIJ CRM 5401-a, Cyclohexane for Thermal Analysis

    International Nuclear Information System (INIS)

    Highlights: • We developed a new CRM for quality assurance of DSC and DTA below room temperature. • Certified values are temperatures and enthalpies of two phase transitions. • Certified values agree with literature values. • Certified values are determined by adiabatic calorimetry and traceable to the SI. • Purity of this CRM was confirmed more than 0.9999. - Abstract: For the quality assurance of performance of differential scanning calorimeters (DSC) and differential thermal analyzers (DTA) below room temperature, we have developed “NMIJ CRM 5401-a, Cyclohexane for Thermal Analysis” applicable to calibration of DSC and DTA in the low temperature. Adiabatic calorimetry was used to measure the temperatures and enthalpies of solid–solid phase transition and fusion as certified values, and to determine the purity in amount of substance fraction as information. The certified values are consistent with their corresponding literature values within expanded uncertainties and have traceability to the SI. Purity in amount of substance fraction was measured by fractional melting method based on freezing point depression method and was confirmed to be more than 0.9999. NMIJ CRM 5401-a was produced based on a quality system in compliance with ISO Guide 34: 2000. We demonstrate the usefulness of NMIJ CRM 5401-a in the calibration, quality control, and validation aspects of DSC and DTA

  3. Simultaneous Thermodynamic and Kinetic Parameters Determination Using Differential Scanning Calorimetry

    Directory of Open Access Journals (Sweden)

    Nader Frikha

    2011-01-01

    Full Text Available Problem statement: The determination of reaction kinetics is of major importance, as for industrial reactors optimization as for environmental reasons or energy limitations. Although calorimetry is often used for the determination of thermodynamic parameters alone, the question that arises is: how can we apply the Differential Scanning Calorimetry for the determination of kinetic parameters. The objective of this study consists to proposing an original methodology for the simultaneous determination of thermodynamic and kinetic parameters, using a laboratory scale Differential Scanning Calorimeter (DSC. The method is applied to the dichromate-catalysed hydrogen peroxide decomposition. Approach: The methodology is based on operating of experiments carried out with a Differential Scanning Calorimeter. The interest of this approach proposed is that it requires very small quantities of reactants (about a few grams to be implemented. The difficulty lies in the fact that, using such microcalorimeters, the reactants temperature cannot directly be measured and a particular calibration procedure has thus to be developed, to determine the media temperature in an indirect way. The proposed methodology for determination of kinetics parameters is based on resolution of the coupled heat and mass balances. Results: A complete kinetic law is proposed. The Arrhenius parameters are determined as frequency factor k0 = 1.39×109 s−1 and activation energy E = 54.9 kJ mol−1. The measured enthalpy of reaction is ΔrH=−94 kJ mol−1. Conclusion: The comparison of the results obtained by such an original methodology with those obtained using a conventional laboratory scale reactor calorimetry, for the kinetics determination of, shows that this new approach is very relevant.

  4. Pcm inclusion in gypsum boards for thermal energy storage through latent heat: thermal characterization with DSC; Incorporacion de materiales de cambio de fase en placas de yeso para almacenamiento de energia termica mediante calor latente: caracterizacion termica del material mediante la tecnica DSC

    Energy Technology Data Exchange (ETDEWEB)

    Oliver, A.; Neila, F. J.; Garcia, A.

    2011-07-01

    Differential Scanning Calorimetry (DSC) is a thermal analysis technique which has been used for more than three decades to measure the temperatures and heat flows associated with transitions in materials as a function of time. Other techniques, are Differential Thermal Analysis DTA and Conventional Calorimetry. There is great uncertainty in the values supplied by the manufacturers (because they are referred to pure substances) and the DSC should be used to get more accurate values. It will be analyzed the thermal storage capacity depending on temperature for several compound materials formed by some aggregates, mainly gypsum and phase change materials, in various proportions. The results have been compared with other building materials such as gypsum boards and brick layer. The suitability of the new construction material for thermal energy storage will be assessed in comparison with other materials traditionally used for this purpose. (Author) 21 refs.

  5. Development of Quartz Fiber Calorimetry

    CERN Multimedia

    2002-01-01

    % RD40 \\\\ \\\\ Very Forward Calorimeters (VFCs) in LHC detectors should cover the pseudorapidity range from $\\eta$~=~2.5 to at least $\\eta$~=~5 in order to compute missing transverse energy and for jet tagging. Operation at such high rapidity requires the use of a calorimetry technique that is very radiation resistant, fast and insensitive to radioactivity (especially to neutrons). This can be accomplished through the Quartz-Calorimeter~(Q-Cal) concept of embedding silica core fibers, that resist to the Gigarad radiation level, into an absorber. In this calorimeter the shower particles produce light through the Cherenkov effect generating a signal less than 10~ns in duration. Unique to this new technology the visible energy of hadronic showers has a transverse dimension nearly an order of magnitude smaller than that in conventional calorimeters, enabling precise spatial resolution, sharper isolation cuts and better jet recognition against the minimum bias events background. Last but not least, most radioactive ...

  6. Tritium inventory measurements using calorimetry

    International Nuclear Information System (INIS)

    In the past calorimetry has been developed as a powerful tool in radiometrology. Calorimetric methods have been applied for the determination of activities, half lives and mean energies released during the disintegration of radioactive isotopes. The fundamental factors and relations which determine the power output of radioactive samples are presented and some basic calorimeter principles are discussed in this paper. At the Kernforschungszentrum Karlsruhe (KfK) a family of 3 calorimeters has been developed to measure the energy release from radiative waste products arising from reprocessing operations. With these calorimeters, radiative samples with sizes from a few cm3 to 2 ·105 cm3 and heat ratings ranging from a few nW to kW can be measured. After modifications of tits inner part the most sensitive calorimeter among the three calorimeters mentioned above would be best suited for measuring the tritium inventory in T-getters of the Amersham-type

  7. Micromegas for imaging hadronic calorimetry

    CERN Document Server

    Adloff, C; Cap, S; Chefdeville, M; Dalmaz, A; Drancourt, C; Espargiliere, A; Gaglione, R; Gallet, R; Geffroy, N; Jacquemier, J; Karyotakis, Y; Peltier, F; Prast, J; Vouters, G

    2011-01-01

    The recent progress in R&D of the Micromegas detectors for hadronic calorimetry including new engineering-technical solutions, electronics development, and accompanying simulation studies with emphasis on the comparison of the physics performance of the analog and digital readout is described. The developed prototypes are with 2 bit digital readout to exploit the Micromegas proportional mode and thus improve the calorimeter linearity. In addition, measurements of detection efficiency, hit multiplicity, and energy shower profiles obtained during the exposure of small size prototypes to radioactive source quanta, cosmic particles and accelerator beams are reported. Eventually, the status of a large scale chamber (1{\\times}1 m2) are also presented with prospective towards the construction of a 1 m3 digital calorimeter consisting of 40 such chambers.

  8. DSC modelling for predicting resilient modulus of crushed rock base as a road base material for Western Australia roads

    Institute of Scientific and Technical Information of China (English)

    KHOBKLANG Pakdee; VIMONSATIT Vanissorn; JITSANGIAM Peerapong; NIKRAZ Hamid

    2013-01-01

    In order to increase the applied efficiency of crushed rock base (CRB) in pavement structure design for Western Australia roads,the material modelling based on the experimental results was investigated,and the disturbed state concept (DSC) was used to predict the resilient modulus of CRB because of its simplicity and strong ability in capturing the elastic and inelastic responses of materials to loads.The actual deformation of DSC,at any loading state,was determined from its assumed relative intact (RI) state.The DSC equation of CRB was constructed by using a set of experimental results of resilient modulus tests,and an idealized material model,namely the linear elastic model,of relative intact (RI) part was considered.Analysis results reveal that the resilient modulus-applied stress relationships back-predicted by using the DSC modelling are consistent with the experimental results,so,the DSC equation is suited for predicting the resilient modulus of CRB specimen.However,the model and the equation coming from the test results are conducted in accordance with the Austroads standard,so further investigation and validation with respect to the field behaviours of pavement structure should be performed.7 figs,11 refs.

  9. DMSO-Induced Dehydration of DPPC Membranes Studied by X-ray Diffraction, Small-Angle Neutron Scattering, and Calorimetry

    OpenAIRE

    Kiselev, M. A.; Lesieur, P.; Kisselev, A. M.; Grabielle-Madelmond, C.; Ollivon, M.

    2001-01-01

    The influence of dimethyl sulfoxide (DMSO) on membrane thickness, multilamellar repeat distance, and phase transitions of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) was investigated by X-ray diffraction and small-angle neutron scattering (SANS). The differential scanning calorimetry (DSC) study of water freezing and ice melting was performed in the ternary DPPC /DMSO /water and binary DMSO /water systems. The methods applied demonstrated the differences in membrane structure in t...

  10. Scan-rate dependence in protein calorimetry: the reversible transitions of Bacillus circulans xylanase and a disulfide-bridge mutant.

    OpenAIRE

    J Davoodi; Wakarchuk, W. W.; Surewicz, W K; Carey, P. R.

    1998-01-01

    The stabilities of Bacillus circulans xylanase and a disulfide-bridge-containing mutant (S100C/N148C) were investigated by differential scanning calorimetry (DSC) and thermal inactivation kinetics. The thermal denaturation of both proteins was found to be irreversible, and the apparent transition temperatures showed a considerable dependence upon scanning rate. In the presence of low (nondenaturing) concentrations of urea, calorimetric transitions were observed for both proteins in the second...

  11. Dijet mass resolution and compensating calorimetry

    International Nuclear Information System (INIS)

    The calorimetry for SSC detectors has as its role the detection of the basic particles of the Standard Model. Those germane to calorimetry are quarks, photons, electrons, and gluons. Note that all the hadronic entities appear in the calorimetry as jets. The detection of single hadrons belongs to a past era when ''quark molecules'' were the focus of intense study. Thus, the goal of calorimetry at the SSC must be the study of jets. In particular, one must understand what defines the limits of accuracy of the jets. If there are intrinsic physical processes which limit the precision of jet measurements, then calorimetry which is more accurate is unnecessary if not wasteful. 5 refs., 5 figs

  12. Radiation Induced Aging Effects in Polymeric Cable Insulators at CERN. Compilation of the DSC and ATR-FTIR data on irradiated CERN cables.

    CERN Document Server

    Sorin, I

    2009-01-01

    This second part of the Report on Radiation Induced Aging Effects in Polymeric Cable Insulators at CERN [1] summarizes in a tabulated form all the experimental DSC results obtained in this work, concerning the life-time evaluation of the selected CERN cables irradiated in different conditions. Several examples of DSC curves and ATR-FTIR spectra were included to support the future polymeric materials analysis. Information on the experimental conditions, the instruments, the basic concept of life-time evaluation using the DSC data, as well as the examples of data processing and interpretation are presented and discussed in reference [1].

  13. Differential scanning calorimetry predicts the critical quality attributes of amorphous glibenclamide

    DEFF Research Database (Denmark)

    Mah, Pei T; Laaksonen, Timo; Rades, Thomas;

    2015-01-01

    Selection of a crystallinity detection tool that is able to predict the critical quality attributes of amorphous formulations is imperative for the development of process control strategies. The main aim of this study was to determine the crystallinity detection tool that best predicts the critical...... quality attributes (i.e. physical stability and dissolution behaviour) of amorphous material. Glibenclamide (model drug) was milled for various durations using a planetary mill and characterised using Raman spectroscopy and differential scanning calorimetry (DSC). Physical stability studies upon storage...... the superiority of DSC (onset of crystallisation) in detecting residual crystallinity in the samples milled for between 60 and 120min, which were not detectable with Raman spectroscopy. The physical stability upon storage and dissolution behaviour of the milled samples improved with increased milling...

  14. First application of simultaneous SANS and differential scanning calorimetry: Microphase separated alkane blends

    International Nuclear Information System (INIS)

    For almost 30 years, it has been possible at synchrotron facilities to perform small-angle x-ray scattering experiments whilst simultaneously measuring phase transitions using differential scanning calorimetry (DSC). However, a range of challenges exist to enable the collection of simultaneous small-angle neutron scattering (SANS) and DSC data associated not only with intrinsic flux limitations but also scattering geometry and thermal control. The development of a DSC (temperature range ca. −150 C to 500 C) suitable for SANS is detailed here which, to our knowledge, is the first and only one of its kind. An example study is presented from the 40 m SANS instrument, QUOKKA, at the OPAL reactor at ANSTO (Figure 1), concerned with phase transitions in a binary blend of normal alkanes in which one component has been deuterium labelled[1]. The ability to conduct simultaneous DSC and neutron scattering studies allows investigators to use these two complementary techniques to provide insight into structural and thermal changes and opens up the opportunity for SANS to make significant new contributions to a range of systems in which either scattering contrast is insufficient for SAXS studies or where neutron scattering is essential or inherently desirable (e.g. isotope effects).

  15. WA80 BGO calorimetry electronics

    International Nuclear Information System (INIS)

    This paper describes instrumentation designed for BGO scintillator-based calorimetry of particles covering a very wide range of energies (from less than 50 MeV to 50 GeV). The instrumentation was designed to have a measurement accuracy of 0.1% over as much of the energy range as possible so the energy resolution of BGO would be the limiting factor. Two 1.5-cm2 photodiodes were used per 2.5 cm x 2.5 cm x 25 cm BGO crystal. Both a charge-sensitive preamplifier and a pulse processor were developed specifically for the needs of the WA80 experiment. The preamplifier was designed for high detector capacitance (100 to 700 pF), low integral and differential non-linearity and low power consumption (200 mW). The pulse processor is a time-invariant shaping amplifier with integral peak-detect-and-hold and automatic gain selection circuits. The amplifier use quasi-triangular shaping with 4 μs peaking time, and the hold circuit is gated with a fast first level trigger. The system has more than 20 bits of effective resolution when used with an external 12-bit ADC. Results from beam tests at CERN are presented. 6 refs., 5 figs., 1 tab

  16. Kinetics of the thermal degradation of Erica arborea by DSC: Hybrid kinetic method

    CERN Document Server

    Cancellieri, Dominique; Rossi, Jean Louis; 10.1016/j.tca.2005.07.013

    2008-01-01

    The scope of this work was the determination of kinetic parameters of the thermal oxidative degradation of a Mediterranean scrub using a hybrid method developed at the laboratory. DSC and TGA were used in this study under air sweeping to record oxidative reactions. Two dominating and overlapped exothermic peaks were recorded in DSC and individualized using an experimental and numerical separation. This first stage allowed obtaining the enthalpy variation of each exothermic phenomenon. In a second time, a model free method was applied on each isolated curve to determine the apparent activation energies. A reactional kinetic scheme was proposed for the global exotherm composed of two independent and consecutive reactions. In fine mean values of enthalpy variation and apparent activation energy previously determined were injected in a model fitting method to obtain the reaction order and the preexponential factor of each oxidative reaction. We plan to use these data in a sub-model to be integrated in a wildland ...

  17. Thermal degradation of ligno-cellulosic fuels. DSC and TGA studies

    Energy Technology Data Exchange (ETDEWEB)

    Leroy, V.; Cancellieri, D.; Leoni, E. [SPE-CNRS UMR 6134, University of Corsica, Campus Grossetti, BP 52, 20250 Corti (France)

    2006-12-01

    The scope of this work was to show the utility of thermal analysis and calorimetric experiments to study the thermal oxidative degradation of Mediterranean scrubs. We investigated the thermal degradation of four species; DSC and TGA were used under air sweeping to record oxidative reactions in dynamic conditions. Heat released and mass loss are important data to be measured for wildland fires modelling purpose and fire hazard studies on ligno-cellulosic fuels. Around 638 and 778K, two dominating and overlapped exothermic peaks were recorded in DSC and individualized using a experimental and numerical separation. This stage allowed obtaining the enthalpy variation of each exothermic phenomenon. As an application, we propose to classify the fuels according to the heat released and the rate constant of each reaction. TGA experiments showed under air two successive mass loss around 638 and 778K. Both techniques are useful in order to measure ignitability, combustibility and sustainability of forest fuels. (author)

  18. Thermal degradation of ligno-cellulosic fuels: DSC and TGA studies

    CERN Document Server

    Leroy, Valérie; Leoni, Eric; 10.1016/j.tca.2006.09.017

    2008-01-01

    The scope of this work was to show the utility of thermal analysis and calorimetric experiments to study the thermal oxidative degradation of Mediterranean scrubs. We investigated the thermal degradation of four species; DSC and TGA were used under air sweeping to record oxidative reactions in dynamic conditions. Heat released and mass loss are important data to be measured for wildland fires modelling purpose and fire hazard studies on ligno-cellulosic fuels. Around 638 and 778 K, two dominating and overlapped exothermic peaks were recorded in DSC and individualized using a experimental and numerical separation. This stage allowed obtaining the enthalpy variation of each exothermic phenomenon. As an application, we propose to classify the fuels according to the heat released and the rate constant of each reaction. TGA experiments showed under air two successive mass loss around 638 and 778 K. Both techniques are useful in order to measure ignitability, combustibility and sustainability of forest fuels.

  19. DSC and TMA studies on freezing and thawing gelation of galactomannan polysaccharide

    Energy Technology Data Exchange (ETDEWEB)

    Iijima, Mika, E-mail: m-iijima@nagasaki-u.ac.jp [Faculty of Education, Nagasaki University, 1-14, Bunkyo-machi, Nagasaki 852-8521 (Japan); Hatakeyama, Tatsuko [Lignocell Research, 73-8 Yatsumata, Fukui 910-3558 (Japan); Hatakeyama, Hyoe [Department of Environment and Biotechnology, Faculty of Engineering, Fukui University of Technology, 3-6-1, Gakuen, Fukui 910-8505 (Japan)

    2012-03-20

    Research highlights: Black-Right-Pointing-Pointer Locust bean gum forms hydrogels by freezing and thawing. Black-Right-Pointing-Pointer Syneresis was observed when freezing and thawing cycle (n) increased. Black-Right-Pointing-Pointer Dynamic Young's modulus increased with increasing n. Black-Right-Pointing-Pointer Non-freezing water content restrained by hydrogels decreased with increasing n. Black-Right-Pointing-Pointer Strong gel with densely packed network structure formed with increasing n. - Abstract: Among various kinds of polysaccharides known to form hydrogels, locust bean gum (LBG) consisting of a mannose backbone and galactose side chains has unique characteristics, since LBG forms hydrogels by freezing and thawing. In this study, effect of thermal history on gelation was investigated by differential scanning calorimetry (DSC) and thermomechanical analysis (TMA). Gel/sol ratio calculated by weighing method was found to be affected by sol concentration, freezing rate and the number of freezing and thawing cycle (n). Once LBG hydrogels are formed, they are thermally stable, although syneresis was observed when n increased. Dynamic Young's modulus (E Prime ) of hydrogels measured by TMA in water increased with increasing n and decreasing freezing rate. Non-freezing water calculated from DSC melting peak of ice in the gel decreased with increasing n and decreasing freezing rate. Morphological observation of freeze-dried gels was carried out by scanning electron microscopy (SEM). The above results indicate that weak hydrogel having large molecular network structure transformed into strong gel with densely packed network structure by increasing n and decreasing freezing rate.

  20. Cryomilled Aluminum with Diamantane: Thermal Characterization by DSC and Effects of Magnesium

    Science.gov (United States)

    Arnold, Michael Colin

    Many structural applications require a material that is both lightweight and corrosion resistant, for which aluminum and its alloys may be considered for use if not for their relatively low strength. By improving strength of aluminum through the Hall-Petch mechanism, it could become a more suitable choice for many structural applications. Cryomilling is used as a production technique to strengthen aluminum by reduction of grain size to the 20-50 nm range. Although the powders produced by cryomilling are well within the nanocrystalline regime, the powders experience significant grain growth during consolidation to a solid body. Cryomilled powders have been shown to remain nanocrystalline by introducing a nano-diamond, diamantane to the grain boundaries. To better characterize the thermal stability of the cryomilled powder with diamantane, Differential Scanning Calorimetry (DSC) was used to measure the isothermal heat flow in the 0.6Tm to 0.9Tm range. A model was developed to correlate the isothermal DSC signal to a grain growth curve and grain growth parameters were elucidated by assuming variable boundary mobility with a sigmoidal form. The model revealed a tendency for boundary mobility to transition from an athermal grain growth mechanism to standard thermally activated grain growth. Grain growth parameters were compared to shed light on possible mechanisms of aluminum-diamantane involvement during grain growth. Powders and consolidated samples with very low concentrations of diamantane and with magnesium were observed by TEM, SEM and XRD, and compared both separately and together to characterize the how thermal stability is affected by diamantane concentration and the presence of magnesium.

  1. Kinetics Characteristics of Nitrogen Hydrates Respond to Differential Scanning Calorimetry

    Science.gov (United States)

    Chen, Q.; Liu, C.; Ye, Y.; Gong, J.

    2012-12-01

    In this study, a high pressure differential scanning calorimetry (HP DSC) based on thermo-analytical technique was applied to investigate the kinetics and thermodynamics characteristics of nitrogen hydrates. Nitrogen hydrates was synthesized in the sample vessel under different pressures as temperature decreased from 293 to 233 K with a constant cooling rate of 0.2 K/min controlled by the DSC. To measure the hydrates dissociation enthalpies , the temperature was slowly raised up from 233 to 293 K at a constant rate ranging of 0.05 K/min. 1. Peak area on the heat flow curves represents the amount of heat during phase transition. In these experiments, the total water added to the sample vessel (mt) is already known. By integrating the peak areas of ice and hydrate, we know the total heats of ice (Qi) and hydrate (Qh), respectively. As the heat of ice per gram can be measured easily (336.366 J/g), the mass of ice (mi) can be obtain. Then, the dissociation heat of nitrogen hydrate per gram (Hh ) can be calculated by the equation: H(J/g)=Qh/(mt-mi) It is shown that the dissociation heats of nitrogen hydrates are a little larger than ice, but do not change a lot with different pressures. The average value of dissociation heat is 369.158 J/g. 2. During the DSC cooling stage, hydrate formed at temperature much lower than equilibrium. The biggest sub-cooling is about 291 K, while the smallest one is about 279 K. However, during these experiments, the pressure did not show obvious relationship with sub-cooling. It confirmed that even the proper conditions were achieved, formation was still a stochastic process. For one thing, due to the random distribution of dissolved gas in water, the interfacial tension and the water activity were not equal in the whole system. And if there was a free gas phase, which leads to different fugacity on water-gas interface, the stochastic behavior would be more significant in the sample vessel. 3. The energy released from hydrates formation as

  2. Experimental studies on hydrogen/deuterium evolution from zirconium alloy based matrices using TGA-EGA

    International Nuclear Information System (INIS)

    Measurement of Hydrogen isotopes (H/D) is very critical in quality control and life management of pressure tubes (PT) in PHWRs. Main techniques used for measurement of Heq are Differential Scanning Calorimetry (DSC), Hot Vacuum Extraction-Quadrupole Mass Spectrometry (HVE-QMS) and Inert Gas Fusion and extraction Technique (IGF). In this paper, experimental studies on H/D evolution from Zirconium based alloys have been reported as a function of temperature. It will be helpful in studying the extraction characteristics of H/D isotopes in Zirconium based matrices and fixing the extraction parameters for analysis by various techniques. (author)

  3. Automatic calorimetry system monitors RF power

    Science.gov (United States)

    Harness, B. W.; Heiberger, E. C.

    1969-01-01

    Calorimetry system monitors the average power dissipated in a high power RF transmitter. Sensors measure the change in temperature and the flow rate of the coolant, while a multiplier computes the power dissipated in the RF load.

  4. Entropy production in ac-calorimetry

    OpenAIRE

    Garden, Jean-Luc; Richard, Jacques

    2007-01-01

    In calorimetry and particularly in heat capacity measurements, different characteristic relaxation time constants may perturb the experiment which cannot be considered at thermodynamic equilibrium. In this case, thermodynamics of irreversible processes has to be taken into account and the calorimetric measurements must be considered as dynamic. In a temperature modulated experiment, such as ac-calorimetry, these non-equilibrium experiments give rise to the notion of frequency dependent comple...

  5. Melting and thermal history of poly(hydroxybutyrate-co-hydroxyvalerate) using step-scan DSC

    International Nuclear Information System (INIS)

    Melting behaviour and crystal morphology of poly(3-hydroxybutyrate) (PHB) and its copolymer of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with various hydroxyvalerate (HV) contents [5 wt.% (PHB5HV), 8 wt.% (PHB8HV) and 12 wt.% (PHB12HV)] have been investigated by conventional DSC, step-scan differential scanning calorimetry (SDSC) and hot-stage polarised optical microscopy (HSPOM). Crystallisation behaviour of PHB and its copolymers were investigated by SDSC. Thermal properties were investigated after different crystallisation treatments, fast, medium and slow cooling. Multiple melting peak behaviour was observed for all polymers. SDSC data revealed that PHB and its copolymers undergo melting-recrystallisation-remelting during heating, as evidenced by exothermic peaks in the IsoK baseline (non-reversing signal). An increase in degree of crystallinity due to significant melt-recrystallisation was observed for slow-cooled copolymers. PHB5HV showed different crystal morphologies for various crystallisation conditions. SDSC proved a convenient and precise method for measurement of the apparent thermodynamic specific heat (reversing signal) HSPOM results showed that the crystallisation rates and sizes of spherulites were significantly reduced as crystallisation rate increased

  6. Effect of hydrate formation-dissociation on emulsion stability using DSC and visual techniques

    Energy Technology Data Exchange (ETDEWEB)

    Lachance, J.W.; Dendy Sloan, E.; Koh, C.A. [Colorado School of Mines, Golden, CO (United States). Center for Hydrates Research

    2008-07-01

    Many flow assurance operators are now focusing on preventing hydrates from agglomerating and forming plugs within pipelines. A key factor in reducing plug formation in oil-dominated systems is the stability of emulsified water in gas hydrate formation. In this study, differential scanning calorimetry (DSC) studies were used to show that gas hydrate formation has a destabilizing effect on water and oil emulsions, and can result in a free water phase through the coalescence and agglomeration of dissociated hydrate particles. The study focused on investigating the ability of the hydrates to stay segregated with hydrate formation. The stability of water-in-oil emulsions with hydrate formation was investigated with a range of different crude oils with varying emulsion stability levels. Thermal properties were measured at both atmospheric and pressurized conditions. Thermocouples in the calorimetric furnace were used to measure the temperature difference between reference and sample cells. Emulsion stability was measured over a 1-month time period. Results of the study showed that hydrate formation and dissociation destabilizes emulsions. However, the asphaltene fraction in crude oils resists hydrate-induced destabilization. The stability of the emulsion increased when asphaltene content increased. It was concluded that emulsion stability is a key factor in preventing agglomeration in flow lines. 14 refs., 3 tabs., 8 figs.

  7. Study of the crystallization kinetics of LAS glass by differential scanning calorimetry, X-ray diffraction, and beam bending viscometry

    International Nuclear Information System (INIS)

    Highlights: ► The crystallization of LAS glass was investigated using XRD, DSC and beam bending viscometry. ► Different models were used to determine the kinetic parameters for crystallization. ► The activation energy and Avrami parameters obtained are consistent with reported values. ► The crystallization of LAS glass occurs with three-dimensional crystals growth. - Abstract: The crystallization kinetics of a commercial lithium-aluminum silicate (LAS) glass were characterized by differential scanning calorimetry (DSC) under non-isothermal conditions, by in-situ X-ray diffraction, and by three point beam bending viscosimeter (BBV). Non-isothermal DSC experiments were conducted at different heating rates. Results show that the crystal growth is controlled by a thermally activated process of the Arrhenius type. The activation energies obtained from isoconversional analysis are close to that extracted using the Johnson–Mehl–Avrami equation. While X-ray diffraction volume fraction data confirm the DSC analysis, it also shows that the crystallite size changes only at the end of the heat treatment protocol, during a hold at temperatures as high as 1000 °C. In this latter case, the crystal growth follows the Ostwald ripening mechanism. Finally, the viscosity measured in the crystallization region by BBV provides the activation energy for viscous flow, and it is slightly higher than the values obtained by DSC.

  8. Thermal Properties of Silk Fibroin Using Fast Scanning Calorimetry

    Science.gov (United States)

    Cebe, Peggy; Partlow, Benjamin; Kaplan, David; Wurm, Andreas; Zhuravlev, Evgeny; Schick, Christoph

    We performed fast scanning chip-based calorimetry of silk protein using the Mettler Flash DSC1. We suggest the methodology by which to obtain quantitative information on the very first scan to high temperature, including the melting endotherm of the beta pleated sheets. For proteins, this first scan is the most important one, because the crystalline secondary structural features, the beta pleated sheets, melt after the first heating and cannot be thermally reintroduced. To obtain high quality data, the samples must be treated to drying and enthalpy relaxation sequences. The heat flow rates in heating and cooling must be corrected for asymmetric heat loses. We evaluate methods to obtain an estimate of the sample mass, finally choosing internal calibration using the known heat capacity increment at the glass transition. We report that even heating at rates of 2000 K/s, thermal degradation of silk cannot be totally avoided, though it can be minimized. Using a set of nineteen samples, we successfully determine the liquid state heat capacity of silk as: Cpliquid (T) = (1.98 +0.06) J/gK + T (6.82 +1.4) x10-4 J/gK2. Methods for estimation of the sample mass will be presented and compared. National Science Foundation, Polymers Program DMR-1206010; DAAD; Tufts Faculty Supported Leave.

  9. Study of the developed precipitates in Al-0.63Mg-0.37Si-0.5Cu (wt.%) alloy by using DSC and TEM techniques

    Energy Technology Data Exchange (ETDEWEB)

    Gaber, A. [Physics Department, Faculty of Science, Assiut University (Egypt)]. E-mail: gaberaf@acc.aun.edu.eg; Ali, A. Mossad [Physics Department, Faculty of Science, Assiut University (Egypt); Matsuda, K. [Faculty of Engineering, University of Toyama (Japan); Kawabata, T. [Faculty of Engineering, University of Toyama (Japan); Yamazaki, T. [Faculty of Engineering, University of Toyama (Japan); Ikeno, S. [Faculty of Engineering, University of Toyama (Japan)

    2007-04-25

    Heat treatable Al-Mg-Si containing Cu alloys can be strengthened by the precipitation of the nano-scale metastable precipitates. In order to follow the precipitation sequence in balanced Al-1 mass%Mg{sub 2}Si containing 0.5 mass%Cu during continuous heating, differential scanning calorimetry (DSC) was performed. Analysis of non-isothermal DSC scans at various heating rates were carried out to evaluate the overall activation energies associated with the precipitation processes and, therefore, the mechanism of the developed precipitates has been characterized. The most important developed precipitates that assist the strength of the alloy are random, Q' and {beta}' precipitates. According to the obtained activation energies, the kinetics of the evolved Q'-precipitates could be controlled by the diffusion of Mg, Si and Cu in the crystal lattice of the alloy. Both conventional and high resolution transmission electron microscopy (HRTEM) were utilized to confirm the obtained results.

  10. Thermodynamic Property Study of Nano structured Mg-H, Mg-Ni-H, and Mg-Cu-H Systems by High Pressure DSC Method

    International Nuclear Information System (INIS)

    Mg, Ni, and Cu nanoparticles were synthesized by hydrogen plasma metal reaction method. Preparation of Mg2Ni and Mg2Cu alloys from these Mg, Ni, and Cu nanoparticles has been successfully achieved in convenient conditions. High pressure differential scanning calorimetry (DSC) technique in hydrogen atmosphere was applied to study the synthesis and thermodynamic properties of the hydrogen absorption/desorption processes of nano structured Mg-H, Mg-Ni-H, and Mg-Cu-H systems. Van’t Hoff equation of Mg-Ni-H system as well as formation enthalpy and entropy of Mg2NiH4 was obtained by high pressure DSC method. The results agree with the ones by pressure-composition isotherm (PCT) methods in our previous work and the ones in literature.

  11. TOPEM DSC study of glass transition region of polyurethane cationomers

    International Nuclear Information System (INIS)

    Highlights: ► TOPEM DSC method was employed to investigate the glass transition (Tg) region of fluorinated polyurethane cationomers. ► Introduction of fluorine compounds significantly changes thermal behaviour of cationomers in the Tg region of hard segments. ► Introduction of fluorine compound leads to changes of the slope in activation diagram of glass transition. - Abstract: In this paper TOPEM DSC method was employed to investigate the glass transition region of fluorinated polyurethane cationomers. Fluorinated polyurethane cationomers have been synthesised in the reaction of MDI with poly(ethylene glycol) (600) and butane1,4-diol or N-methyl- or N-butyldiethanolamine and 2,2,3,3-tetrafluoro-1,4-butanediol. Better rigidity was found for generally amorphous cationomer coats. It was found that introduction of fluorine compound changes thermal behaviour of polyurethane cationomers as well as leads to changes in the slope in activation diagram profiles of glass transition in comparison to polyuretahene cationomer without fluorine compound. Application of TOPEM DSC allows to obtain more information concerning frequency dependence of glass transition region and thermodynamical stability of polyurethane structures.

  12. Thermodynamic properties of isomeric iso-butoxybenzoic acids: Experimental and theoretical study

    International Nuclear Information System (INIS)

    Highlights: • Vapor pressures of butoxy benzoic acid derivatives were measured. • Vaporization, sublimation and fusion enthalpies were derived. • Molar enthalpies of formation were measured by calorimetry. • Thermochemical data tested for consistency using additivity rules and computations. • Simple additivity method suggested for prediction thermochemical properties. - Abstract: Standard (p° = 0.1 MPa) molar enthalpies of formation at the temperature T = 298.15 K of the 2-, 3-, and 4-iso-butoxybenzoic acids were measured using the combustion calorimetry. Standard molar enthalpies of vaporization and sublimation were derived from the vapor pressure temperature dependencies measured by the transpiration method. Molar enthalpies of the solid state phase transitions were measured by the DSC. Thermodynamic data on alkoxy substituted benzoic acids available in the literature were collected and combined with own experimental results. This data set on alkoxybenzoic acids was evaluated by using quantum-chemical and group-additivity methods

  13. Thermodynamic properties of isomeric iso-butoxybenzoic acids: Experimental and theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Jakubczyk, Michał; Sporzyński, Andrzej [Faculty of Chemistry, Warsaw University of Technology, 00-664 Warszawa (Poland); Emel’yanenko, Vladimir N.; Varfolomeev, Mikhail A. [Department of Physical Chemistry, Kazan Federal University, 420008 Kazan (Russian Federation); Verevkin, Sergey P., E-mail: sergey.verevkin@uni-rostock.de [Department of Physical Chemistry, Kazan Federal University, 420008 Kazan (Russian Federation); Department of Physical Chemistry and Department, Science and Technology of Life, Light and Matter, University of Rostock, D-18059 Rostock (Germany)

    2015-09-10

    Highlights: • Vapor pressures of butoxy benzoic acid derivatives were measured. • Vaporization, sublimation and fusion enthalpies were derived. • Molar enthalpies of formation were measured by calorimetry. • Thermochemical data tested for consistency using additivity rules and computations. • Simple additivity method suggested for prediction thermochemical properties. - Abstract: Standard (p° = 0.1 MPa) molar enthalpies of formation at the temperature T = 298.15 K of the 2-, 3-, and 4-iso-butoxybenzoic acids were measured using the combustion calorimetry. Standard molar enthalpies of vaporization and sublimation were derived from the vapor pressure temperature dependencies measured by the transpiration method. Molar enthalpies of the solid state phase transitions were measured by the DSC. Thermodynamic data on alkoxy substituted benzoic acids available in the literature were collected and combined with own experimental results. This data set on alkoxybenzoic acids was evaluated by using quantum-chemical and group-additivity methods.

  14. COMPARATIVE KINETICS STUDY OF THE THERMAL AND THERMO-OXIDATIVE DEGRADATION OF A POLYSTYRENE-CLAY NANOCOMPOZITE BY TGA AND DSC

    Directory of Open Access Journals (Sweden)

    Ion Dranca

    2010-12-01

    Full Text Available The methods of thermogravimetry (TGA and differential scanning calorimetry (DSC have been used to study the thermal and thermo-oxidative degradation of polystyrene (PS and a PS-clay nanocomposite. An advanced isoconversional method has been applied for kinertic analysis. Introduction of the clay phase increasers the activation energy and affects the total heat of degradation, which suggests a change in the reaction mechanism. The obtained kinetic data permit a comparative assessment of the fire resistance of the studied materials

  15. Thermodynamic properties of methylquinolines: Experimental results for 2,6-dimethylquinoline and mutual validation between experiments and computational methods for methylquinolines

    Energy Technology Data Exchange (ETDEWEB)

    Chirico, Robert D. [Physical and Chemical Properties Division, National Institute of Standards and Technology (NIST), Boulder, CO 80305-3328 (United States)]. E-mail: chirico@boulder.nist.gov; Johnson, Russell D. [Physical and Chemical Properties Division, National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899-8380 (United States)]. E-mail: rjohnson@nist.gov; Steele, William V. [Physical Properties Research Facility, Chemical Engineering Department, 327 Dougherty Engineering Building, 1512 Middle Drive, University of Tennessee, Knoxville, TN 37996-2200 (United States) and Nuclear Science and Technology Division, Oak Ridge National Laboratory (ORNL), Oak Ridge, TN 37831-6273 (United States)]. E-mail: steelewv@ornl.gov

    2007-05-15

    Measurements leading to the calculation of the standard thermodynamic properties for gaseous 2,6-dimethylquinoline (Chemical Abstracts registry number [877-43-0]) are reported. Experimental methods included adiabatic heat-capacity calorimetry, vibrating-tube densimetry, comparative ebulliometry, inclined-piston gauge manometry, differential-scanning calorimetry (d.s.c.), and combustion calorimetry. The critical temperature was measured with d.s.c. The critical pressure and critical density were estimated. Molar entropies, molar enthalpies, and molar Gibbs free energies of formation for the ideal gas state were derived at selected temperatures between 298.15 K and 700 K. Results are compared with experimental property values reported previously in the literature. Independent calculations of the ideal gas entropies were performed at the B3LYP/6-31+G(d,p) model chemistry for 2,6-dimethylquinoline and other methylquinolines (including hindered internal rotations) and are shown to be in excellent accord with the calorimetric results. Implications of these results are discussed.

  16. Characterization of moisture-protective polymer coatings using differential scanning calorimetry and dynamic vapor sorption.

    Science.gov (United States)

    Bley, O; Siepmann, J; Bodmeier, R

    2009-02-01

    The aim of this study was to evaluate the moisture-protective ability of different polymeric coatings. Free films and film-coated tablets (with cores containing freeze-dried garlic powder) were prepared using aqueous solutions/dispersions of hydroxypropyl methylcellulose (HPMC), Opadry AMB [a poly(vinylalcohol)-based formulation] and Eudragit E PO [a poly(methacrylate-methylmethacrylate)]. The water content of the systems upon open storage at 75% relative humidity (RH) and 22 degrees C (room temperature) was followed gravimetrically. Furthermore, polymer powders, free films and coated tablets were analyzed by differential scanning calorimetry (DSC) and dynamic vapor sorption (DVS). The type of polymer strongly affected the resulting water uptake kinetics of the free films and coated tablets. DSC analysis revealed whether or not significant physical changes occurred in the coatings during storage, and whether the water vapor permeability was water concentration dependent. Using DVS analysis the critical glass transition RH of Opadry AMB powder and Opadry AMB-coated tablets at 25 degrees C could be determined: 44.0% and 72.9% RH. Storage below these threshold values significantly reduces water penetration. Thus, DVS and DSC measurements can provide valuable information on the nature of polymers used for moisture protection. PMID:18481311

  17. DSC and X-ray diffraction studies on the physicochemical changes occurring in polyester films exposed to heavy ion irradiation

    International Nuclear Information System (INIS)

    Poly(ethylene terephthalate) (PET) (commercial biaxially oriented Mylar and Hostaphan, 23 and 19 μm thick) and poly(butylene terephthalate) (PBT) (80μm thick) films were exposed to heavy ion irradiation and the resulting structural transformations were studied by differential scanning calorimetry (Perkin-Elmer DSC-7, heating rate in nitrogen flow , 2 or 3 K/min, open pans; heating cooling-heating cycles run at rates of 10-10-10 K/min, and 2-20-2 K/min, closed pans), wide-angle and small angle X-ray scattering (WAXS and SAXS), Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), and density measurements. The PBT film was prepared from the molten phase and then heated at 150oC. They were irradiated with Ar ions (5.5 MeV/amu, 1011 ions /cm2), Dy ions (13 MeV/amu, 1-5x1010 and 1011 ions/cm2), and Pb ions (11.4 MeV/amu, 1010 ions/cm2). The calculated radiation doses were found to be contained with the range of (1.1-22.0)x105 Gy. The irradiation-effected different film melting and crystallization courses detected by DSC and the changes in reflection intensities in WAXS diffractograms indicated to a reduced crystal phase content in the irradiated polyester films. The amorphization of the PET film was confirmed by SAXS and FTIR spectra and also by density measurements. As found by GPC, the molecular weight of the soluble fraction in PET decreases on irradiation and the accompanying increase in the content of the insoluble phase indicates that cross-linking process occur. The DSC and X-ray techniques proved to be helpful in following the structural changes induced in polymer films by irradiation with heavy ions. (author)

  18. Study of asphaltene precipitation by Calorimetry

    DEFF Research Database (Denmark)

    Verdier, Sylvain Charles Roland; Plantier, Frédéric; Bessières, David; Andersen, Simon Ivar; Stenby, Erling Halfdan; Carrier, Hervé

    2007-01-01

    Can calorimetry bring new input to the Current understanding of asphaltene precipitation? In this work, two types of precipitation were studied by means of calorimetry: addition of n-heptane into asphaltene solutions and temperature/pressure variations on a recombined live oil. The first series of...... experiments showed that weak forces determine precipitation. Indeed, isothermal titration calorimetry could not detect any clear signal although this technique can detect low-energy transitions such as liquid-liquid equilibrium and rnicellization. The second series of tests proved that precipitation caused by...... T and P variations is exothermic for this system. Furthermore, the temperature-induced precipitation is accompanied by an increase in the apparent thermal expansivity. Therefore, it seems that these two phase transitions exhibit different calorimetric behaviours and they may not be as similar as...

  19. A Study of Concept Mapping as an Instructional Intervention in an Undergraduate General Chemistry Calorimetry Laboratory

    Science.gov (United States)

    Stroud, Mary W.

    This investigation, rooted in both chemistry and education, considers outcomes occurring in a small-scale study in which concept mapping was used as an instructional intervention in an undergraduate calorimetry laboratory. A quasi-experimental, multiple-methods approach was employed since the research questions posed in this study warranted the use of both qualitative and quantitative perspectives and evaluations. For the intervention group of students, a convenience sample, post-lab concept maps, written discussions, quiz responses and learning surveys were characterized and evaluated. Archived quiz responses for non-intervention students were also analyzed for comparison. Students uniquely constructed individual concept maps containing incorrect, conceptually correct and "scientifically thin" calorimetry characterizations. Students more greatly emphasized mathematical relationships and equations utilized during the calorimetry experiment; the meaning of calorimetry concepts was demonstrated to a lesser extent.

  20. A DSC STUDY OF PHOTOPOLYMERIZATION OF POLYESTERS CONTAINING CONJUGATED DIACETYLENES

    Institute of Scientific and Technical Information of China (English)

    Yao-wen Bai; Xiao-fang Chen; Dong Zhang; Xin-hua Wan; Qi-feng Zhou

    2000-01-01

    The photopolymerization of two kinds of prepolyesters containing conjugated diacetylene (PDA-6 and PDA-12)was investigated using DSC. By measuring the endothermic enthalpy of the prepolymers after different UV-irradiation times,the polymerizations were found to follow the first-order rate law which agreed with the results of other investigators using a different method. The endothermic enthalpy measurements of PDA-6 and PDA-12 before UV-irradiation precluded the possibility that the decrease of endothermic enthalpy was caused by thermal polymerization.

  1. Heat capacity measurements of petroleum fuels by modulated DSC

    Energy Technology Data Exchange (ETDEWEB)

    Zanier, A.; Jaeckle, H.W. [Fuels and Lubricants Department of the Swiss Federal Laboratories for Materials Testing and Research EMPA, Duebendorf (Switzerland)

    1996-10-01

    In this work, the usefulness of modulated DSC (MDSC) for measuring the heat capacity of commercial hydrocarbon fuels is illustrated. Specifically, the reliability of the method is outlined by testing five liquid fuels of diverse composition and origin over a temperature range between -70C and 70C. The experiments were carried out using a DSC 2910 module from TA Instruments Inc., upgraded with the MDSC option. The samples were exposed to a cyclic heating profile which was generated by a linear heating rate of 2C min{sup -1} while simultaneously superimposing a sinusoidally varying time-temperature wave with an amplitude of {+-}0.5C and a period of 100s. On the basis of these measurements, MDSC proved to be a valuable technique with which to measure directly the heat capacity of hydrocarbon fuels. Moreover, the ability of MDSC to measure heat capacity with great accuracy and precision offers a powerful approach for studying the effects of compositional differences on heat capacity

  2. Reticulation of Aqueous Polyurethane Systems Controlled by DSC Method

    Directory of Open Access Journals (Sweden)

    Jakov Stamenkovic

    2006-06-01

    Full Text Available The DSC method has been employed to monitor the kinetics of reticulation ofaqueous polyurethane systems without catalysts, and with the commercial catalyst of zirconium(CAT®XC-6212 and the highly selective manganese catalyst, the complex Mn(III-diacetylacetonemaleinate (MAM. Among the polyol components, the acrylic emulsions wereused for reticulation in this research, and as suitable reticulation agents the water emulsiblealiphatic polyisocyanates based on hexamethylendoisocyanate with the different contents ofNCO-groups were employed. On the basis of DSC analysis, applying the methods of Kissinger,Freeman-Carroll and Crane-Ellerstein the pseudo kinetic parameters of the reticulation reactionof aqueous systems were determined. The temperature of the examination ranged from 50oC to450oC with the heat rate of 0.5oC/min. The reduction of the activation energy and the increaseof the standard deviation indicate the catalytic action of the selective catalysts of zirconium andmanganese. The impact of the catalysts on the reduction of the activation energy is thestrongest when using the catalysts of manganese and applying all the three afore-said methods.The least aberrations among the stated methods in defining the kinetic parameters wereobtained by using the manganese catalyst.

  3. New crystals for dual-readout calorimetry

    Czech Academy of Sciences Publication Activity Database

    Akchurin, N.; Bedeschi, F.; Cardini, A.; Carosi, R.; Ciapetti, G.; Ferrari, R.; Franchino, S.; Fraternali, M.; Gaudio, G.; Hauptman, J.; Incagli, M.; Korzhik, M.; Lacava, F.; La Rotonda, L.; Livan, M.; Meoni, E.; Nikl, Martin; Pinci, D.; Policicchio, A.; Popescu, S.; Scuri, F.; Sill, A.; Vandelli, W.; Vedda, A.; Venturelli, T.; Voena, C.; Volobouev, I.; Wigmans, R.

    2009-01-01

    Roč. 604, č. 3 (2009), s. 512-526. ISSN 0168-9002 Institutional research plan: CEZ:AV0Z10100521 Keywords : calorimetry * Cherenkov light * high-Z scintillating crystals Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.317, year: 2009

  4. HDTHe calorimetry v.1.0

    Energy Technology Data Exchange (ETDEWEB)

    2016-01-12

    The software generates predicted results of differential scanning calorimetry experiments for samples of palladium in a perforated capsule in an atmosphere containing a mixture of hydrogen isotopologues and helium. It can also be used to predict the results of absorption-desorption experiments at constant temperature and solid-phase isotopic ratio.

  5. Final Technical Report CMS fast optical calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Winn, David R. [Fairfield Univ., CT (United States)

    2012-07-12

    This is the final report of CMS FAST OPTICAL CALORIMETRY, a grant to Fairfield University for development, construction, installation and operation of the forward calorimeter on CMS, and for upgrades of the forward and endcap calorimeters for higher luminosity and radiation damage amelioration.

  6. Calculation of Temperature Rise in Calorimetry.

    Science.gov (United States)

    Canagaratna, Sebastian G.; Witt, Jerry

    1988-01-01

    Gives a simple but fuller account of the basis for accurately calculating temperature rise in calorimetry. Points out some misconceptions regarding these calculations. Describes two basic methods, the extrapolation to zero time and the equal area method. Discusses the theoretical basis of each and their underlying assumptions. (CW)

  7. Effect of sonication applied during production of carbon fiber/epoxy resin composites evaluated by differential scanning calorimetry and thermo-gravimetric analysis

    OpenAIRE

    Bogoeva-Gaceva, Gordana; Dimeski, Dimko; Herakovic, Niko

    2011-01-01

    The influence of ultrasonic treatment, applied during the impregnation of carbon fiber bundle by epoxy resin system, on thermal behavior of carbon fiber/epoxy resin composites in the course of crosslinknetwork formation has been analyzed by differential scanning calorimetry (DSC). It was previously shown [1] that this treatment has resulted in drastically increased interlaminar shear strength (ILSS) of the bulk composites, produced by hot pressing. The enhanced ILSS was attributed...

  8. Detection of cervical cancer biomarker patterns in blood plasma and urine by differential scanning calorimetry and mass spectrometry.

    Directory of Open Access Journals (Sweden)

    Nichola C Garbett

    Full Text Available Improved methods for the accurate identification of both the presence and severity of cervical intraepithelial neoplasia (CIN and extent of spread of invasive carcinomas of the cervix (IC are needed. Differential scanning calorimetry (DSC has recently been shown to detect specific changes in the thermal behavior of blood plasma proteins in several diseases. This methodology is being explored to provide a complementary approach for screening of cervical disease. The present study evaluated the utility of DSC in differentiating between healthy controls, increasing severity of CIN and early and advanced IC. Significant discrimination was apparent relative to the extent of disease with no clear effect of demographic factors such as age, ethnicity, smoking status and parity. Of most clinical relevance, there was strong differentiation of CIN from healthy controls and IC, and amongst patients with IC between FIGO Stage I and advanced cancer. The observed disease-specific changes in DSC profiles (thermograms were hypothesized to reflect differential expression of disease biomarkers that subsequently bound to and affected the thermal behavior of the most abundant plasma proteins. The effect of interacting biomarkers can be inferred from the modulation of thermograms but cannot be directly identified by DSC. To investigate the nature of the proposed interactions, mass spectrometry (MS analyses were employed. Quantitative assessment of the low molecular weight protein fragments of plasma and urine samples revealed a small list of peptides whose abundance was correlated with the extent of cervical disease, with the most striking plasma peptidome data supporting the interactome theory of peptide portioning to abundant plasma proteins. The combined DSC and MS approach in this study was successful in identifying unique biomarker signatures for cervical cancer and demonstrated the utility of DSC plasma profiles as a complementary diagnostic tool to evaluate

  9. Differential scanning calorimetry study of glycerinated rabbit psoas muscle fibres in intermediate state of ATP hydrolysis

    Directory of Open Access Journals (Sweden)

    Farkas Nelli

    2007-06-01

    Full Text Available Abstract Background Thermal denaturation experiments were extended to study the thermal behaviour of the main motor proteins (actin and myosin in their native environment in striated muscle fibres. The interaction of actin with myosin in the highly organized muscle structure is affected by internal forces; therefore their altered conformation and interaction may differ from those obtained in solution. The energetics of long functioning intermediate states of ATP hydrolysis cycle was studied in muscle fibres by differential scanning calorimetry (DSC. Results SETARAM Micro DSC-II was used to monitor the thermal denaturation of the fibre system in rigor and in the presence of nucleotide and nucleotide analogues. The AM.ADP.Pi state of the ATP hydrolysis cycle has a very short lifetime therefore, we mimicked the different intermediate states with AMP.PNP and/or inorganic phosphate analogues Vi and AlF4 or BeFx. Studying glycerol-extracted muscle fibres from the rabbit psoas muscle by DSC, three characteristic thermal transitions were detected in rigor. The thermal transitions can be assigned to myosin heads, myosin rods and actin with transition temperatures (Tm of 52.9 ± 0.7°C, 57.9 ± 0.7°C, 63.7 ± 1.0°C. In different intermediate states of the ATP hydrolysis mimicked by nucleotide analogues a fourth thermal transition was also detected which is very likely connected with nucleotide binding domain of myosin and/or actin filaments. This transition temperature Tm4 depended on the mimicked intermediate states, and varied in the range of 66°C – 77°C. Conclusion According to DSC measurements, strongly and weakly binding states of myosin to actin were significantly different. In the presence of ADP only a moderate change of the DSC pattern was detected in comparison with rigor, whereas in ADP.Pi state trapped by Vi, AlF4 or BeFx a remarkable stabilization was detected on the myosin head and actin filament which is reflected in a 3.0 – 10.0

  10. DIFFERENTIAL SCANNING CALORIMETRY AND X-RAY DIFFRACTION STUDIES ON AGING BEHAVIOR OF Zn-Al ALLOYS

    Institute of Scientific and Technical Information of China (English)

    X.L. Xu; Z.W. Yu; S.J. Ji; J.C. Sun; Z.K. Hei

    2001-01-01

    Decomposition processes of the quenched Zn-Al alloys were studied by differentiai scanning calorimetry (DSC), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that the stabilities of supersaturated solid solution (SSS) of Zn-Al alloy and c' phase formed by quenching would reduce with increasing Zn content and precipitating η-Zn phases even when aging at ambient temperature,so that exothermic precipitation peak in DSC curve would disappear. The activation energy of the η-Zn precipitation and their reaction enthalpy were calculated and measured. The kinetics of α' decomposition or η-Zn formation was determined by XRD.The microstructure change during aging was observed by TEM.

  11. Raman scattering boson peak and differential scanning calorimetry studies of the glass transition in tellurium-zinc oxide glasses

    Energy Technology Data Exchange (ETDEWEB)

    Stavrou, E; Tsiantos, C; Tsopouridou, R D; Kripotou, S; Kontos, A G; Raptis, C [Department of Physics, National Technical University of Athens, GR-15780 Athens (Greece); Capoen, B; Bouazaoui, M [Laboratoire de Physique des Lasers, Atomes et Molecules (CNRS, UMR 8523), Batiment P-5, Centre d' Etudes et de Recherches Lasers et Applications (CERLA-FR CNRS 2416), Universite de Sciences et Technologies de Lille, F-59655 Villeneuve d' Ascq Cedex (France); Turrell, S; Khatir, S, E-mail: craptis@central.ntua.g [Laboratoire de Spectrochimie Infrarouge et Raman (CNRS 8516), Batiment C-5, Centre d' Etudes et de Recherches Lasers et Applications (CERLA-FR CNRS 2416), Universite de Sciences et Technologies de Lille, F-59655 Villeneuve d' Ascq Cedex (France)

    2010-05-19

    Raman scattering and differential scanning calorimetry (DSC) measurements have been carried out on four mixed tellurium-zinc oxide (TeO{sub 2}){sub 1-x}(ZnO){sub x} (x = 0.1, 0.2, 0.3, 0.4) glasses under variable temperature, with particular attention being given to the respective glass transition region. From the DSC measurements, the glass transition temperature T{sub g} has been determined for each glass, showing a monotonous decrease of T{sub g} with increasing ZnO content. The Raman study is focused on the low-frequency band of the glasses, the so-called boson peak (BP), whose frequency undergoes an abrupt decrease at a temperature T{sub d} very close to the respective T{sub g} values obtained by DSC. These results show that the BP is highly sensitive to dynamical effects over the glass transition and provides a means for an equally reliable (to DSC) determination of T{sub g} in tellurite glasses and other network glasses. The discontinuous temperature dependence of the BP frequency at the glass transition, along with the absence of such a behaviour by the high-frequency Raman bands (due to local atomic vibrations), indicates that marked changes of the medium range order (MRO) occur at T{sub g} and confirms the correlation between the BP and the MRO of glasses.

  12. CFD simulation of a TG–DSC furnace during the indium phase change process

    International Nuclear Information System (INIS)

    Highlights: ► Working behaviour in TGA–DSC is studied. ► A CFD model of the original device is simulated. ► Indium is employed as sample and a melting model is programmed. ► Heat flux to the sample is computed. ► Experimental and simulated results are compared. -- Abstract: A ThermoGravimetric Analyser with Differential Scanning Calorimeter (TGA–DSC) was modelled and simulated to evaluate heat transfer to the sample and the internal operation of the equipment. For this purpose, a mesh was generated based on a CAD design of the real geometry, and several models were applied. Some of these models were built into the CFD commercial software, and some were developed by the authors. Realistic boundary conditions were applied, and a control system based on PID operation was implemented to manage the heat released by an electrical resistance, similar to the real equipment. Finally, simulation results were obtained and contrasted with real data.

  13. DSC Study on Polypropylene Modified with Calcium Carbonate Nanoparticles

    International Nuclear Information System (INIS)

    The exposure of polypropylene containing various concentrations of calcium carbonate nanoparticles was performed in air and water. The radiolysis products of water determine different behaviour of polymer substrate. The irradiation effect induced on polymer and the contribution of nanoparticles to the scavenging of oxygenated products that were created during γ exposure were investigated by DSC measurements over the temperature range from 340-400 K, the usual temperatures for thermal overcharge. Two kinds of carbonate particles, one type is represented by unmodified filler, while the second type is the superficially modified with stearic acid. The covering of particle surface with stearic acid confers to them a different ability in the abstraction of degradation products formed in irradiated isotactic polypropylene

  14. CRYSTALLIZATION SEGREGATION DSC STUDIES OF PP/PE COPOLYMERS

    Institute of Scientific and Technical Information of China (English)

    Yu Ma; Ying Wang; Shan-nong Zhu; Mao Xu

    2001-01-01

    The structural analysis of two PP/PE copolymer samples, I and 2, was conducted by using 13C-NMR, GPC and crystallization segregation DSC (CSDSC) techniques. A pure polypropylene sample was also used for comparison. It was found that the two copolymer samples are very close in composition (the ethylene mol content is 4.3% and 4.5%,respectively), stereoregularity (96% and 97%) and molecular weight (Mw, = 7.0 x 104 and 7.3x104; Mw/Mn = 5.0 and 6.1,respectively). While the CSDSC thermograms of the two samples are quite different from each other. Sample 1 shows a higher average melting temperature and a broader distribution of its thermogram. These phenomena were explained as an indication of a less uniform distribution of ethylene units along the PP chains for sample 1. It was noted that CSDSC is a very sensitive and convenient technique for structural studies of copolymers.

  15. DSC melting behavior of irradiated low density polyethylenes containing antioxidants

    International Nuclear Information System (INIS)

    The effect of antioxidants (0.5 wt% content) on the melting behaviour of low density polyethylenes, one branched and one linear, was examined with data obtained by DSC. The two polyethylenes exhibit noticeable differences in pure form: LLDPE has a higher melting point, lower heat of fusion and a more complex fusion endotherm than LDPE. The addition of antioxidants has a scarcely noticeable influence on the melting behaviour of LDPE whether irradiated or not, while in the case of LLDPE the effect is more visible. However, a careful analysis of the observed characteristics, peak temperatures and lamellae thickness distribution as well as heat of fusion, show that the observed effects are appearing as the consequence of chemical processes, scission and crosslinking, which occur in PE under either thermomechanical action (mixing in the course of the sample preparation), or radiation. (author)

  16. INVESTIGATION OF THE TRANSITIONS OF OLIGO-POLYSULFONES BY DSC

    Institute of Scientific and Technical Information of China (English)

    DONG Lisong; ZHENG Guodong; FENG Zhiliu

    1987-01-01

    The transitions of bisphenol A and phenolphthalein oligopolysulfones were investigated by DSC. It is found that both the oligomers have three transitions within the temperature range (230-550K) studied.Considering the strong dependence of the appearance of the two transitions, lower and higher than Tg, on the specimens' thermal history, i.e., temperature and time of heat-treatment, and their particular molecular structure, it is proposed that these two transitions are morphological in origin and are due to the disordering of relatively short range order of very small regions, and to the disordering of relatively well-ordered intraor/and intermolecular segments, respectively. Equations for linear relationship between Tg and 1/(M)(n)for both the oligomers are given in the paper.

  17. Detection of a new 'nematic-like' phase in liquid crystal-amphiphile mixture by differential scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Dan, Kaustabh, E-mail: kaustabhdan@gmail.com; Roy, Madhusudan, E-mail: kaustabhdan@gmail.com; Datta, Alokmay, E-mail: kaustabhdan@gmail.com [Surface Physics and Materials Science Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar Block, Sector 1, Kolkata-700064 (India)

    2014-04-24

    Differential Scanning Calorimetry (DSC) studies on phase transitions of the pure liquid crystalline material N-4-methoxybenzylidene-4-butylaniline (MBBA) and mixtures of MBBA and the amphiphile Stearic Acid (StA) show significant changes in the behavior of mixture from pure MBBA, as regards the nematic-isotropic (N-I) transition temperature (T{sub c}) and other thermodynamic parameters like enthalpy, specific heat and activation energy with concentration of StA. In particular, the convexity of the Arrhenius plot in pure MBBA vanishes with StA concentration pointing to the formation of a new, perhaps 'nematic-like', phase in the mixtures.

  18. Cerium fluoride crystals for calorimetry at LHC

    International Nuclear Information System (INIS)

    High-resolution homogeneous calorimetry is fully justified for part of the physics program at the Large Hadron Collider (LHC). The main design features of proposed CeF3 crystals for calorimetry for LHC are discussed. The severe constraints LHC imposes on detectors make the use of 'classical' crystals impossible. Therefore, a large R and D effort has been undertaken by the 'Crystal Clear' collaboration in order to find new, dense, fast and radiation hard crystals. A good candidate, cerium fluoride, has been identified and studied. It is interesting at this stage to review the specifications of scintillators for LHC and to see how well available data on CeF3 luminescence, decay time, light yield, optical transmission and resistance to radiation meet them. Milestones to reach before starting a large scale crystal production in view of the eventual construction of a calorimeter, are also discussed. (author) 15 refs., 15 figs., 1 tab

  19. A modulated DSC characterization of morphology of composite latex particles

    International Nuclear Information System (INIS)

    A modulated differential scanning calorimetry (MDSC) method combining transmission electron microscopy (TEM) for characterizing the morphology of composite latex particles has been developed. Sulfonated polystyrene (S-PS)/poly(methyl methacrylate) (PMMA) (50:50 by weight) composite latex particles were prepared as model samples. PS particles were prepared by self-emulsification using lightly S-PS in co-solvents/water. For the preparation of S-PS/PMMA composite latex particles, the guest methyl methacrylate (MMA) monomers first diffused into swollen S-PS particles in S-PS aqueous dispersions, and then the MMA monomers were polymerized. Based on the MDSC method, one can determine quickly whether and what kinds of composite latex particles are prepared. Combing TEM, morphological parameters, such as the radius of core, diffused-phase thickness and thickness of shell of the composite latex particles, can be obtained

  20. A modulated DSC characterization of morphology of composite latex particles

    Energy Technology Data Exchange (ETDEWEB)

    Song, M.; Liao, B

    2004-12-01

    A modulated differential scanning calorimetry (MDSC) method combining transmission electron microscopy (TEM) for characterizing the morphology of composite latex particles has been developed. Sulfonated polystyrene (S-PS)/poly(methyl methacrylate) (PMMA) (50:50 by weight) composite latex particles were prepared as model samples. PS particles were prepared by self-emulsification using lightly S-PS in co-solvents/water. For the preparation of S-PS/PMMA composite latex particles, the guest methyl methacrylate (MMA) monomers first diffused into swollen S-PS particles in S-PS aqueous dispersions, and then the MMA monomers were polymerized. Based on the MDSC method, one can determine quickly whether and what kinds of composite latex particles are prepared. Combing TEM, morphological parameters, such as the radius of core, diffused-phase thickness and thickness of shell of the composite latex particles, can be obtained.

  1. The glass transition process in humid biopolymers. DSC study

    International Nuclear Information System (INIS)

    Thermal properties of native and denatured biopolymers with quite different chemical and steric structure (globular and fibrillar proteins, DNA, starches) were studied by means of differential scanning calorimetry in a wide range of temperatures and concentrations of water. It was shown that both native and denatured humid biopolymers are glassy systems. The glass transition temperature of these systems strongly depends on percentage of water, with water being simultaneously an intrinsic element of systems' ordered structure and a plasticizer of its amorphous state. On the base of the absolute values of heat capacities for biopolymer-water systems as a whole, heat capacities for biopolymers themselves were calculated as functions on water concentration at fixed temperatures. The S-shaped change of heat capacity observed on diagrams of state both for native and denatured biopolymers is the manifestation of biopolymers' passing through the vitrification region, as it occurs for denatured samples at heating

  2. CDF [Collider Detector at Fermilab] calorimetry

    International Nuclear Information System (INIS)

    The Collider Detector at Fermilab (CDF) is a large detector built to study 2 TeV anti p p collisions at the Fermilab Tevatron. The calorimetry, which has polar angle coverage from 20 to 1780, and complete azimuthal coverage within this region, forms the subject of this paper. It consists of both electromagnetic shower counters (EM calorimeters) and hadron calorimeters, and is segmented into about 5000 ''towers'' or solid angle elements

  3. Analysis of Cooperativity by Isothermal Titration Calorimetry

    OpenAIRE

    Alan Brown

    2009-01-01

    Cooperative binding pervades Nature. This review discusses the use of isothermal titration calorimetry (ITC) in the identification and characterisation of cooperativity in biological interactions. ITC has broad scope in the analysis of cooperativity as it determines binding stiochiometries, affinities and thermodynamic parameters, including enthalpy and entropy in a single experiment. Examples from the literature are used to demonstrate the applicability of ITC in the characterisation of coop...

  4. Calorimetry and thermodynamics of living systems

    International Nuclear Information System (INIS)

    Calorimetry of living systems and classical thermodynamics developed in parallel, from Lavoisier's early ice calorimeter experiments on guinea pigs, followed by Dubrunfaut's macrocalorimetric research of fermentation processes and Atwater-Rosa's whole-body calorimetry on humans and domestic animals, to the introduction of the famous Tian-Calvet instrument that found entrance into so many different fields of biology. In this work, six examples of living-system calorimetry and thermodynamics are presented. These are: (i) glycolytic oscillations far off the thermodynamic equilibrium; (ii) growth and energy balances in fermenting and respiring yeast cultures; (iii) direct and indirect calorimetric monitoring of electrically stimulated reptile metabolism; (iv) biologic and climatic factors influencing the temperature constancy and distribution in the mound of a wood ant colony as an example of a complex ecological system; (v) energetic considerations on the clustering of European honeybees in winter as a means to save energy and stored food as well as for their Japanese counterparts in defending against hornet predators; and (vi) energetic and evolutionary aspects of the mass specific entropy production rate, the so-called bound dissipation or psiu-function. The examples presented here are just a very personal selection of living systems from a broad spectrum at all levels of complexity. Common for all of them is that they were investigated calorimetrically on the background of classical and irreversible thermodynamics

  5. Missing energy induced by thin hadron calorimetry

    International Nuclear Information System (INIS)

    It is relatively straightforward to estimate the total, unsegmented, depth required in SSC experiments. Typically depths in the range of 9--11 absorption lengths were specified by the SDC and GEM experiments. With these depths, the induced missing energy signal due to calorimeter leakage was found to be well below the signals caused by light gluinos, and the exterior muon systems were well protected from punch through backgrounds. In certain applications, where calorimetry is inscribed inside the magnetic field producing coils, that depth of calorimetry becomes exceedingly expensive. Examples are the ZEUS barrel and the proposed CMS barrel calorimeters. The problems can be alleviated by placing a ''tailcatcher'' of active elements outside the coil, but the problem of inert material placed within the active volume of the calorimetry remains. This inert material can potentially induce missing transverse energy signals which are large with respect to real physics signatures. The purpose of this note is to explore schemes to minimize the measured leakage energy

  6. Thermodynamic properties of three-ring aza-aromatics. 1. Experimental results for phenazine and acridine, and mutual validation of experiments and computational methods

    International Nuclear Information System (INIS)

    Measurements leading to the calculation of thermodynamic properties for phenazine (Chemical Abstracts registry number [92-82-0]) in the ideal-gas state are reported. Experimental methods included adiabatic heat-capacity calorimetry, inclined-piston manometry, and combustion calorimetry. Thermodynamic properties for acridine (Chemical Abstracts registry number [260-94-6]) were reported previously and included those measured with adiabatic heat-capacity calorimetry, comparative ebulliometry, inclined-piston manometry, and combustion calorimetry. New measurement results for acridine reported here are densities determined with a vibrating-tube densimeter and heat capacities for the liquid phase at saturation pressure determined with a differential-scanning calorimeter (d.s.c.). All critical properties were estimated. Molar entropies for the ideal-gas state were derived for both compounds at selected temperatures. Independent calculations of entropies for the ideal-gas state were performed at the B3LYP/6-31+G(d, p) model chemistry for phenazine and acridine. These are shown to be in excellent accord with the calorimetric results. All results are compared with experimental property values reported in the literature.

  7. Utilisation de la DSC pour la caractérisation de la stabilité des émulsions eau dans pétrole Use of the Dsc Technique to Characterize Water-In-Crude Oil Emulsions Stability

    Directory of Open Access Journals (Sweden)

    Dalmazzone C.

    2006-12-01

    Full Text Available La technique DSC (Differential Scanning Calorimetry a été appliquée à l'étude des émulsions eau dans pétrole, qui se forment naturellement après un déversement de pétrole en mer. Ces émulsions, également appelées mousses au chocolat , peuvent contenir de 50 à 80% d'eau et se présentent souvent sous la forme d'un produit visqueux, difficile à récupérer mécaniquement, à traiter ou à brûler. Il est par conséquent important de pouvoir estimer leur stabilité pour optimiser le choix du traitement. Un grand nombre de techniques, généralement fondées sur l'analyse de la distribution de tailles de gouttes, peuvent être utilisées pour estimer la stabilité d'une émulsion. Malheureusement, la plupart ne sont pas adaptées à l'étude des émulsions eau dans huile opaques. La méthode la plus utilisée pour caractériser la stabilité de ce type d'émulsions est le bottle test. Elle consiste à mesurer la séparation de phases en fonction du temps. Ce test est la source d'une quantité d'informations appréciables quant à la stabilité de l'émulsion et à la qualité de la phase aqueuse séparée, mais il reste très empirique. La technique DSC est généralement utilisée pour déterminer la composition des émulsions eau dans huile, car elle permet de distinguer l'eau libre de l'eau émulsifiée. Cette étude a montré qu'il s'agit d'une technique très utile qui permet à la fois l'étude de l'évolution de la taille des gouttes dans l'émulsion, et une détermination précise de la quantité d'eau. The DSC technique (Differential Scanning Calorimetry was applied to the study of water-in-crude oil emulsions, which naturally form after an oil spill. The resulting emulsions contain between 50 and 80% seawater and they are often heavy materials, hard to recover mechanically, treat or burn. It is therefore important to assess their stability in order to optimize their treatments. A great variety of techniques are available for

  8. DETERMINATION OF HYDROGEN DESORBED THROUGH THERMAL CALORIMETRY IN A HIGH STRENGTH STEEL

    Directory of Open Access Journals (Sweden)

    Carolina A. Asmus

    2014-03-01

    Full Text Available The following study aims to quantify the release activation energy (Ea of hydrogen (H from lattice sites, reversible or irreversible, where the H can be trapped. Moreover, enthalpy changes associated with the main hydrogen (H trapping sites can be analyzed by means of differential scanning calorimetry (DSC. In this technique, the peak temperature measurement is determined at two different heating rates, 3ºC/min y 5ºC/min, from ambient temperature to 500°C. In order to simulate severe conditions of hydrogen income into resulfurized high strength steel, electrolytic permeation tests were performed on test tubes suitable for fatigue tests. Sometimes during charging, H promoters were aggregated to electrolytic solution. Subsequently, the test tubes were subjected to flow cycle fatigue tests. Finally, irreversible trap which anchor more strongly H atoms are MnS inclusions. Its role on hydrogen embrittlement during fatigue tests is conclusive.

  9. Laboratory Annealing Experiments Of Refractory Silicate Grain Analogs Using Differential Scanning Calorimetry

    Science.gov (United States)

    Kimura, Yuki; Nuth, Joseph A., III; Tsukamota, Katsuo; Kaito, Chihiro

    2010-01-01

    Exothermic reactions during the annealing of laboratory synthesized amorphous magnesium-bearing silicate particles used as grain analogs of cosmic dust were detected by differential scanning calorimetry (DSC) in air. With infrared spectroscopy and transmission electron microscopy, we show that cosmic dust could possibly undergo fusion to larger particles, with oxidation of magnesium silicide and crystallization of forsterite as exothermic reactions in the early solar system. The reactions begin at approximately 425, approximately 625, and approximately 1000 K, respectively, and the reaction energies (enthalpies) are at least 727, 4151, and 160.22 J per gram, respectively. During the crystallization of forsterite particles, the spectral evolution of the 10 micrometer feature from amorphous to crystalline was observed to begin at lower temperature than the crystallization temperature of 1003 K. During spectral evolution at lower temperature, nucleation and/or the formation of nanocrystallites of forsterite at the surface of the grain analogs was observed.

  10. DSC study and calculation of metronidazole and clarithromycin thermodynamic melting parameters for individual substances and for eutectic mixture

    International Nuclear Information System (INIS)

    Highlights: • The system clarithromycin–metronidazole is a system with a simple eutectic. • The eutectic melting temperature for the system clarithromycin–metronidazole is 155.2 ± 0.5 °C and it is not changed by varying the composition of the system. • The DSC curve for the composition of 89:11 mol or 64.9:35.1 wt% corresponds to the eutectic (or the invariant) composition for the system clarithromycin–metronidazole. - Abstract: In this study melting thermodynamic characteristics of clarithromycin and metronidazole as individual substances were investigated by DSC method. It was found that the binary system of clarithromycin and metronidazole is a system with simple eutectic. Composition, melting temperature and the heat of fusion of the eutectic were determined by calculation and experimental methods

  11. DSC study and calculation of metronidazole and clarithromycin thermodynamic melting parameters for individual substances and for eutectic mixture

    Energy Technology Data Exchange (ETDEWEB)

    Agafonova, Evgeniia V., E-mail: agafonova.ev@samgtu.ru [Samara State Technical University, Molodogvardeyskaya 244, 443100 Samara (Russian Federation); Moshchenskiy, Yuriy V. [Samara State Technical University, Molodogvardeyskaya 244, 443100 Samara (Russian Federation); Tkachenko, Mikhail L., E-mail: tka-mikhail@yandex.ru [Samara State Medical University, Chapaevskaya 89, 443099 Samara (Russian Federation)

    2014-03-01

    Highlights: • The system clarithromycin–metronidazole is a system with a simple eutectic. • The eutectic melting temperature for the system clarithromycin–metronidazole is 155.2 ± 0.5 °C and it is not changed by varying the composition of the system. • The DSC curve for the composition of 89:11 mol or 64.9:35.1 wt% corresponds to the eutectic (or the invariant) composition for the system clarithromycin–metronidazole. - Abstract: In this study melting thermodynamic characteristics of clarithromycin and metronidazole as individual substances were investigated by DSC method. It was found that the binary system of clarithromycin and metronidazole is a system with simple eutectic. Composition, melting temperature and the heat of fusion of the eutectic were determined by calculation and experimental methods.

  12. Hydrogen determinations in a zirconium based alloy with a DSC

    International Nuclear Information System (INIS)

    In the present work a method to measure hydrogen concentrations in zirconium-based alloys was developed measuring simultaneously both, the temperature of terminal solid solubility, TTSSd, and the hydride dissolution heat, Qδ->α, using a differential scanning calorimeter (DSC). The hydrogen concentration measured with that technique, [H]Q, and the values obtained with a standard hydrogen gas meter, [H]HGM, shows a linear relation: [H]Q=(1.00+/-0.03)[H]HGM|+(9.2+/-8.0) with a correlation factor of 0.99 in the entire solubility interval in the αZr phase, from 15 to 650wt.ppm-H. The mean enthalpy value determined with two different criteria for TTSSd and Qδ->α measurements is ΔHδ->α(Q)=39.3+/-1.5kJ/mol H. The present method is specially appropriate for alloys where a partition of the overall hydrogen concentration in two phases exists. It is applicable to all hydride forming metals which ideally follows the van't Hoff law

  13. Profiles in Leadership: Donald E. Francke, MSc, DSc (Hon).

    Science.gov (United States)

    Stevenson, James G; Beham, Rachel E; Weber, Robert J

    2013-10-01

    The Director's Forum series is designed to guide pharmacy leaders in establishing patient-centered services in hospitals and health systems. August 2013 marked the 50th anniversary of the publication of the Mirror to Hospital Pharmacy, the results of a federally funded comprehensive study of pharmacy services in the United States. The late Don E. Francke, MS, DSc, was the lead author of the Mirror and the principal investigator for the US Public Health Service grant W-45. To celebrate the anniversary of the Mirror, the Director's Forum is profiling the leadership styles of Drs. Latiolais and Francke. September's article highlighted Dr. Clifton J. Latiolais; this month's Director's Forum reviews Dr. Francke's biography and key career accomplishments, describes his leadership philosophy, and translates that philosophy to today's health care challenges. Don's influence on health system pharmacy serves as an example of effective leadership. This historical perspective provides directors of pharmacy a valuable leadership view as they develop strategies to enhance patient-centered pharmacy services. PMID:24421553

  14. Design and long-term monitoring of DSC/CIGS tandem solar module

    Science.gov (United States)

    Vildanova, M. F.; Nikolskaia, A. B.; Kozlov, S. S.; Shevaleevskiy, O. I.

    2015-11-01

    This paper describes the design and development of tandem dye-sensitized/Cu(In, Ga)Se (DSC/CIGS) PV modules. The tandem PV module comprised of the top DSC module and a bottom commercial 0,8 m2 CIGS module. The top DSC module was made of 10 DSC mini-modules with the field size of 20 × 20 cm2 each. Tandem DSC/CIGS PV modules were used for providing the long-term monitoring of energy yield and electrical parameters in comparison with standalone CIGS modules under outdoor conditions. The outdoor test facility, containing solar modules of both types and a measurement unit, was located on the roof of the Institute of Biochemical Physics in Moscow. The data obtained during monitoring within the 2014 year period has shown the advantages of the designed tandem DSC/CIGS PV-modules over the conventional CIGS modules, especially for cloudy weather and low-intensity irradiation conditions.

  15. State of the water in crosslinked sulfonated poly(ether ether ketone). Two-dimensional differential scanning calorimetry correlation mapping

    Energy Technology Data Exchange (ETDEWEB)

    Al Lafi, Abdul G. [Department of Chemistry, Atomic Energy Commission, Damascus, P.O. Box 6091 (Syrian Arab Republic); Hay, James N., E-mail: cscientific9@aec.org.sy [The School of Metallurgy and Materials, College of Physical Sciences and Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)

    2015-07-20

    Highlights: • 2D-DSC mapping was applied to analyze the heat flow responses of hydrated crosslinked sPEEK. • Two types of loosely bond water were observed. • The first was bond to the sulfonic acid groups and increased with ion exchange capacity. • The second was attributed to the polar groups introduced by ions irradiation and increased with crosslinking degree. • DSC combined with 2D mapping provides a powerful tool for polymer structural determination. - Abstract: This paper reports the first application of two-dimensional differential scanning calorimetry correlation mapping, 2D-DSC-CM to analyze the heat flow responses of sulphonated poly(ether ether ketone), sPEEK, films having different ion exchange capacity and degrees of crosslinks. With the help of high resolution and high sensitivity of 2D-DSC-CM, it was possible to locate two types of loosely bound water within the structure of crosslinked sPEEK. The first was bound to the sulfonic acid groups and dependent on the ion exchange capacity of the sPEEK. The second was bound to other polar groups, either introduced by irradiation with ions and dependent on the crosslinking degree or present in the polymer such as the carbonyl groups or terminal units. The results suggest that the ability of the sulfonic acid groups in the crosslinked sPEEK membranes to adsorb water molecules is increased by crosslinking, probably due to the better close packing efficiency of the crosslinked samples. DSC combined with 2D correlation mapping provides a fast and powerful tool for polymer structural determination.

  16. State of the water in crosslinked sulfonated poly(ether ether ketone). Two-dimensional differential scanning calorimetry correlation mapping

    International Nuclear Information System (INIS)

    Highlights: • 2D-DSC mapping was applied to analyze the heat flow responses of hydrated crosslinked sPEEK. • Two types of loosely bond water were observed. • The first was bond to the sulfonic acid groups and increased with ion exchange capacity. • The second was attributed to the polar groups introduced by ions irradiation and increased with crosslinking degree. • DSC combined with 2D mapping provides a powerful tool for polymer structural determination. - Abstract: This paper reports the first application of two-dimensional differential scanning calorimetry correlation mapping, 2D-DSC-CM to analyze the heat flow responses of sulphonated poly(ether ether ketone), sPEEK, films having different ion exchange capacity and degrees of crosslinks. With the help of high resolution and high sensitivity of 2D-DSC-CM, it was possible to locate two types of loosely bound water within the structure of crosslinked sPEEK. The first was bound to the sulfonic acid groups and dependent on the ion exchange capacity of the sPEEK. The second was bound to other polar groups, either introduced by irradiation with ions and dependent on the crosslinking degree or present in the polymer such as the carbonyl groups or terminal units. The results suggest that the ability of the sulfonic acid groups in the crosslinked sPEEK membranes to adsorb water molecules is increased by crosslinking, probably due to the better close packing efficiency of the crosslinked samples. DSC combined with 2D correlation mapping provides a fast and powerful tool for polymer structural determination

  17. Differential Scanning Calorimetry for Determining the Thermodynamic Properties of Selected Honeys

    Directory of Open Access Journals (Sweden)

    Tomaszewska-Gras Jolanta

    2015-06-01

    Full Text Available Thermodynamic properties of selected honeys: glass transition temperature (Tg, the change in specifi c heat capacity (ΔCp, and enthalpy (ΔH were analysed using differential scanning calorimetry (DSC in relation to the composition i.e. water and sugar content. Glass transition temperatures (Tg of various types of honey differed significantly (p<0.05 and ranged from -49.7°C (polyfloral to -34.8°C (sunflower. There was a strong correlation between the Tg values and the moisture content in honey (r = -0.94. The degree of crystallisation of the honey also influenced the Tg values. It has been shown that the presence or absence of sugar crystals influenced the glass transition temperature. For the decrystallised honeys, the Tg values were 6 to 11°C lower than for the crystallised honeys. The more crystallised a honey was, the greater the temperature difference was between the decrystallised and crystallized honey. In conclusion, to obtain reliable DSC results, it is crucial to measure the glass transition after the complete liquefaction of honey.

  18. Methodology of hot nucleus calorimetry and thermometry produced by nuclear reactions around Fermi energies

    International Nuclear Information System (INIS)

    This work deals with the calorimetry and thermometry of hot nuclei produced in collisions Xe + Sn between 25 and 100 MeV/u. The apparatus for hot nucleus physical characterization is the 4π detector array Indra. This study was made by using the event generators Gemini, Simon and Hipse and a data-processing filter simulating the complete operation of the multi-detector. The first chapter presents the different ways of producing hot nuclei. In the second and third chapters, the author presents a critical methodological study of calorimetry and thermometry applied to hot nuclei, different methods are reviewed, their accuracy and application range are assessed. All the calorimetry methods rely on the assumption that we are able to discriminate decay products of the hot nucleus from evaporated particles. In the fourth chapter, the author gives some ways of improving calorimetry characterization of the hot nucleus. An alternative method of calorimetry is proposed in the fifth chapter, this method is based on the experimental determination of an evaporation probability that is deduced from the physical characteristics of the particles present in a restricted domain of the space of velocities

  19. Thermal Analysis of Whole Bacterial Cells Exposed to Potassium Permanganate Using Differential Scanning Calorimetry: a Biphasic Dose-Dependent Response to Stress

    Directory of Open Access Journals (Sweden)

    Marina K. Abuladze

    2009-01-01

    Full Text Available Differential scanning calorimetry (DSC was applied to estimate the impact of the toxic oxidant potassium permanganate (PM on the intracellular structural and functional alterations at whole cell level using soil bacteria Arthrobacter oxydans as a model culture. Differential scanning calorimetry (DSC was applied in order to estimate the impact of the toxic oxidant potassium permanganate (PM on the intracellular structural and functional alterations at the whole cell level using the soil bacteria Arthrobacter oxydans as a model culture. We compared the total melting heat and the temperature of DNA-protein complex (DNP melting at the PM application prior to the calorimetry measurement and after 24-h exposure at the concentration range 0.02–1.4 mM. The initial oxidative effect caused changes in the pattern of the whole cell melting spectra (mainly at the temperature range 56–78°C, the decrease of Tmax °C DNP melting, and did not influence significantly the total heat of bacterial melting at different concentrations of PM. The prolonged effect of permanganate up to 24 h was characterized by a biphasic dose-dependent response to stress estimated by the DSC technique and the colony-forming assay. The low doses of PM (0.02 and 0.2 mM stimulated cell proliferation, and increased the total whole cell melting heat and the temperature of DNP melting. The toxic effect of PM up to 0.04 mM reduced cell viability, changed the character of multipeaked thermograms, and lowered the total melting heat and the temperature of DNP melting in a concentration-dependent manner. This study presents the DSC method for evaluating and monitoring the effects of exposure to potential human and environmental toxicants.

  20. Scintillating Fibre Calorimetry at the LHC

    CERN Multimedia

    2002-01-01

    Good electromagnetic and hadronic calorimetry will play a central role in an LHC detector. The lead/scintillating fibre calorimeter technique provides a fast signal response well matched to the LHC rate requirements. It can be made to give equal response for electrons and hadrons (compensation) with good electromagnetic and hadronic energy resolutions.\\\\ \\\\ The aim of this R&D proposal is to study in detail the aspects that are relevant for application of this type of calorimeter in an LHC environment, including its integration in a larger system of detectors, e.g.~projective geometry, radiation hardness, light detection, calibration and stability monitoring, electron/hadron separation.....

  1. Isothermal calorimetry of enzymatic biodiesel reaction

    DEFF Research Database (Denmark)

    Fjerbæk Søtoft, Lene; Westh, Peter; Christensen, Knud Villy;

    2010-01-01

      Isothermal calorimetry ITC has been used to investigate enzymatic biodiesel production. The transesterification of rapeseed oil with methanol and ethanol was catalyzed by the immobilized lipase Novozym 435 at 40°C. The ITC-experiments clearly demonstrate the possibilities of investigating complex...... and composition change in the system, the heat of reaction at 40°C for the two systems has been determined to -9.8 ± 0.9 kJ/mole biodiesel formed from rapeseed oil and methanol, and - 9.3 ± 0.7 kJ/mole when rapeseed oil and ethanol is used....

  2. Calorimetry of the CMD-3 detector

    Science.gov (United States)

    Shebalin, V. E.; Akhmetshin, R. R.; Anisenkov, A. V.; Aulchenko, V. M.; Bashtovoy, N. S.; Epifanov, D. A.; Epshteyn, L. B.; Erofeev, A. L.; Grebenuk, A. A.; Grigoriev, D. N.; Ignatov, F. V.; Kazanin, V. F.; Kovalenko, O. A.; Kozyrev, A. N.; Kuzmenko, A. E.; Kuzmin, A. S.; Logashenko, I. B.; Mikhailov, K. Yu.; Okhapkin, V. S.; Razuvaev, G. P.; Ruban, A. A.; Shwartz, B. A.; Titov, V. M.; Talyshev, A. A.; Yudin, Yu. V.

    2016-07-01

    CMD-3 is a general purpose detector designed to study e+e- annihilation into hadrons. It is mounted at VEPP-2000 collider which operates in the wide energy range, E c . m . s = 0.32 - 2 GeV. The calorimetry at the detector is based on three subsystems: closest to the beam pipe barrel Liquid Xenon calorimeter, outer barrel calorimeter based on CsI scintillation crystals and the endcap calorimeter made of BGO scintillation crystals. We describe the structure of the calorimeters, their electronics and the energy calibration procedures.

  3. Adsorption calorimetry of conjugated organic molecules on metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Lytken, Ole; Drescher, Hans-Joerg; Bebensee, Fabian; Steinrueck, Hans-Peter; Gottfried, J. Michael [Universitaet Erlangen-Nuernberg, Lehrstuhl fuer Physikalische Chemie II (Germany)

    2011-07-01

    Traditional experimental methods for determining adsorption energies, such as temperature programmed desorption (TPD) and equilibrium adsorption isotherms, rely on desorption. However, on many metal surfaces large conjugated organic molecules, such as PTCDA and pentacene, decompose at elevated temperatures before or simultaneously with desorption. Discussions about relative bond strengths are, therefore, typically based on indirect arguments, such as the height of the adsorbed species above the surface as measured with normal incidence X-ray standing waves (NIXSW) or chemical shifts in spectroscopic techniques such as X-ray photoelectron spectroscopy (XPS). Unlike the more traditional methods, nanojoule adsorption calorimetry does not require desorption of the molecules; instead, the heat of adsorption is measured directly as an adsorption-induced temperature change of the sample. We will describe the construction of such a calorimeter at the Universitaet Erlangen-Nuernberg.

  4. Thermodynamic optimization of individual steel database by means of systematic DSC measurements according the CALPHAD approach

    Science.gov (United States)

    Presoly, P.; Six, J.; Bernhard, C.

    2016-03-01

    Reliable thermodynamic data are essential information required for the design of new steel types and are a prerequisite to effective process optimization and simulation. Moreover, it is important to know the exact temperatures at which the high-temperature phase transformations (TLiquid, TSolid, TPerit, Tγ→δ) occur in order to describe the solidification sequence and to describe further processing parameters. By utilizing DTA/DSC measurements, our earlier experimental studies of selected commercial DP, TRIP and high-Mn TWIP steels, have indicated that currently commercially available databases can often not be utilised to reliably describe the behaviour and microstructural development in such complex alloy systems. Because of these ostensible deficiencies, an experimental study was undertaken in an attempt to determine the pertaining thermodynamic data to analyse the behaviour of the important five- component Fe-C-Si-Mn-Al alloy system. High purity model alloys with systematic alloy variations were prepared and utilized in order to determine the influence of individual alloying elements in this complex, but industrially important alloy system. The present study provides new validated experimental thermodynamic data and analysis of the five-component Fe-C-Si- Mn-Al system, which will allow the construction of new phase diagrams, prediction of solidification sequences and the assessment of micro-segregation.

  5. Experimental investigation and modelling of heat capacity, heat of fusion and melting interval of rocks

    Energy Technology Data Exchange (ETDEWEB)

    Leth-Miller, R.; Jensen, A.D.; Glarborg, P.; Jensen, L.M.; Hansen, P.B.; Joergensen, S.B

    2003-11-28

    The heat capacity and heat of fusion were measured for a number of minerals using differential scanning calorimetry (DSC). The DSC measurements showed that the heat of fusion for the minerals is very low compared to the heat of fusion for pure crystalline phases reported elsewhere. A model for the melting behaviour of mineral materials in terms of melting interval, heat capacities and heat of fusion has been developed. The only model input is the chemical composition of the mineral material. The model was developed to be implemented in a detailed model of a cupola furnace, thus the focus for the development was not only precision but also to obtain a model that was continuous and differentiable. The model is based on several different submodels that each covers a part of the heating and melting of rocks. Each submodel is based on large amounts of empirical data. Comparison of the model and the DSC measurements showed reasonable agreement for the model to be used when a fast estimate is needed and experimental data is not available.

  6. Experimental investigation and modelling of heat capacity, heat of fusion and melting interval of rocks

    International Nuclear Information System (INIS)

    The heat capacity and heat of fusion were measured for a number of minerals using differential scanning calorimetry (DSC). The DSC measurements showed that the heat of fusion for the minerals is very low compared to the heat of fusion for pure crystalline phases reported elsewhere. A model for the melting behaviour of mineral materials in terms of melting interval, heat capacities and heat of fusion has been developed. The only model input is the chemical composition of the mineral material. The model was developed to be implemented in a detailed model of a cupola furnace, thus the focus for the development was not only precision but also to obtain a model that was continuous and differentiable. The model is based on several different submodels that each covers a part of the heating and melting of rocks. Each submodel is based on large amounts of empirical data. Comparison of the model and the DSC measurements showed reasonable agreement for the model to be used when a fast estimate is needed and experimental data is not available

  7. Microwave curing of initially compatible epoxy–poly(ethylene terephthalate) blends: DSC kinetic study and nano-structure analysis☆

    International Nuclear Information System (INIS)

    Graphical abstract: The curves proposed to tabulate the curing regime in microwave field. - Highlights: • The monitoring of the curing process in microwave field is the aim of the study. • We consider an approach to estimate the curing regime in microwave field. • We present physical evidences for obtaining nano-modified epoxy composites. - Abstract: Poly(ethylene terephthalate), PET, dissolved in diglycidyl ether of bisphenol-A epoxy resins, DGEBA, is used as a toughening modifier. Two DGEBA resins in the presence of PET have been cured with the aid of diaminodiphenyl sulfone, DDS, in stoichiometric proportion. The curing process of the system DGEBA with DDS, in the presence of PET in particular, is monitored applying differential scanning calorimetry, DSC, in isothermal mode. The curing data are used to estimate the temperature regime in a microwave, MW, cavity. Physical confirmations for obtaining sub-micro phase separated DGEBA–DDS–PET composites and, in turn, for efficient modifying of the epoxy phase, have been discussed

  8. Thermal Hazard Evaluation of Cumene Hydroperoxide-Metal Ion Mixture Using DSC, TAM III, and GC/MS.

    Science.gov (United States)

    You, Mei-Li

    2016-01-01

    Cumene hydroperoxide (CHP) is widely used in chemical processes, mainly as an initiator for the polymerization of acrylonitrile-butadiene-styrene. It is a typical organic peroxide and an explosive substance. It is susceptible to thermal decomposition and is readily affected by contamination; moreover, it has high thermal sensitivity. The reactor tank, transit storage vessel, and pipeline used for manufacturing and transporting this substance are made of metal. Metal containers used in chemical processes can be damaged through aging, wear, erosion, and corrosion; furthermore, the containers might release metal ions. In a metal pipeline, CHP may cause incompatibility reactions because of catalyzed exothermic reactions. This paper discusses and elucidates the potential thermal hazard of a mixture of CHP and an incompatible material's metal ions. Differential scanning calorimetry (DSC) and thermal activity monitor III (TAM III) were employed to preliminarily explore and narrate the thermal hazard at the constant temperature environment. The substance was diluted and analyzed by using a gas chromatography spectrometer (GC) and gas chromatography/mass spectrometer (GC/MS) to determine the effect of thermal cracking and metal ions of CHP. The thermokinetic parameter values obtained from the experiments are discussed; the results can be used for designing an inherently safer process. As a result, the paper finds that the most hazards are in the reaction of CHP with Fe(2+). When the metal release is exothermic in advance, the system temperature increases, even leading to uncontrollable levels, and the process may slip out of control. PMID:27136518

  9. Evaluation of mechanical properties and DSC study of commercial multilayer PA/PE film treated with E-beam radiation

    International Nuclear Information System (INIS)

    Packaging materials have been widely processed by ionizing radiation in order to improve their chemical and physical properties and also for sterilization purposes. Basically, flexible packaging manufacturers apply specific radiation doses to promote cross-linking and scission of the polymeric chains and thus obtain alterations in certain properties of the material. While enhancing a specific property, significant losses may result in others. In this study, we examined the effects of E-beam radiation on a commercial multilayer PA6/LDPE based film, irradiated with doses up to 127 kGy. Food producers mostly use this structure as a thermoforming bottom web for processed meat products. Two weeks after irradiation, tensile strength and elongation of the film were analyzed. Both mechanical properties were again analyzed 18 months after irradiation took place. Significant changes of mechanical properties were observed specially 18 months after irradiation. Once cross-linking and scission are able to affect the material crystalline arrangement and consequently cause properties changes, a DSC ( Differential Scanning Calorimetry) study was carried out for doses up to 130 kGy in order to verify such changes. (author)

  10. Thermal Hazard Evaluation of Cumene Hydroperoxide-Metal Ion Mixture Using DSC, TAM III, and GC/MS

    Directory of Open Access Journals (Sweden)

    Mei-Li You

    2016-04-01

    Full Text Available Cumene hydroperoxide (CHP is widely used in chemical processes, mainly as an initiator for the polymerization of acrylonitrile–butadiene–styrene. It is a typical organic peroxide and an explosive substance. It is susceptible to thermal decomposition and is readily affected by contamination; moreover, it has high thermal sensitivity. The reactor tank, transit storage vessel, and pipeline used for manufacturing and transporting this substance are made of metal. Metal containers used in chemical processes can be damaged through aging, wear, erosion, and corrosion; furthermore, the containers might release metal ions. In a metal pipeline, CHP may cause incompatibility reactions because of catalyzed exothermic reactions. This paper discusses and elucidates the potential thermal hazard of a mixture of CHP and an incompatible material’s metal ions. Differential scanning calorimetry (DSC and thermal activity monitor III (TAM III were employed to preliminarily explore and narrate the thermal hazard at the constant temperature environment. The substance was diluted and analyzed by using a gas chromatography spectrometer (GC and gas chromatography/mass spectrometer (GC/MS to determine the effect of thermal cracking and metal ions of CHP. The thermokinetic parameter values obtained from the experiments are discussed; the results can be used for designing an inherently safer process. As a result, the paper finds that the most hazards are in the reaction of CHP with Fe2+. When the metal release is exothermic in advance, the system temperature increases, even leading to uncontrollable levels, and the process may slip out of control.

  11. Comments on the interpretation of differential scanning calorimetry results for thermoelastic martensitic transformations: Athermal versus thermally activated kinetics

    International Nuclear Information System (INIS)

    In a previous article Van Humbeeck and Planes have made a number of criticisms of the authors' recent paper concerning the interpretation of the results obtained by Differential Scanning Calorimetry (DSC) from the Martensitic Transformation of Cu-Al-Ni-Mn-B alloys. Although the martensitic transformation of these shape memory alloys is generally classified as athermal, it has been confirmed that the capacity of the alloys to undergo a more complete thermoelastic transformation (i.e. better reversibility of the transformation) increased with the Mn content. This behavior has been explained by interpreting the DSC results obtained during thermal cycling in terms of a thermally activated mechanism controlling the direct and reverse transformations. When the heating rate increases during the reverse transformation the DSC curves shift towards higher temperatures while they shift towards the lower temperatures when the cooling rate was increased during the direct transformation. Since the starting transformation temperatures (As, Ms) do not shift, Van Humbeeck and Planes state that there is no real peak shift and assume that the DCS experiments were carried out without taking into account the thermal lag effect between sample and cell. On the following line they deduce a time constant, τ, of 60 seconds because the peak maximum shifts. In fact the assumption made by Van Humbeeck and Planes is false

  12. Synergistic antioxidation of organic molybdenum complex with dithiocarbamate antioxidant evaluated by differential scanning calorimetry and thin film micro oxidation test

    International Nuclear Information System (INIS)

    An oil-soluble sulfur- and phosphorus-free organic molybdenum complex (MC) was synthesized. The antioxidation properties of MC- and methylene bis(di-n-butyldithiocarbamate) (V 7723)-containing poly-α-olefin (PAO)-derived lubricants were evaluated by differential scanning calorimetry (DSC) and modified penn state micro-oxidation test (PMOT). DSC test measures incipient oxidation temperature (OT) and oxidation induction time (IT) of the lubricant at high temperatures and the oxidation stability of oil weight loss is measured by PMOT test. DSC test shows that OT and IT of V 7723-containing PAO were improved significantly by MC addition. PMOT test indicates that when combining with V 7723 antioxidants, MC can also effectively reduce the increase in weight loss of PAO. These results suggest that the MC shows a good oxidative synergism with V 7723 antioxidant. In addition, FTIR results from PMOT test confirm that addition of MC can significantly enhance the oxidation induction time of oils and inhibit formation of oxidation products containing carbonyl bonds or hydroxyl group. The proposed mechanism of the inhibition involves a synergy between MC and V 7723

  13. Experimental investigation of the Mg-Al-Ca system

    International Nuclear Information System (INIS)

    This work focuses on the experimental investigation of the ternary Mg-Al-Ca system using differential scanning calorimetry (DSC), X-ray diffraction (XRD) and metallographic techniques. DSC has permitted real time measurement of the temperature and enthalpy of the phase transformations. One of the invariant transformations predicted by thermodynamic modeling was verified experimentally and found to occur at 513 oC with composition close to 10.8 at.% Ca, 79.5 at.% Mg and 9.7 at.% Al. Three binary compounds are found to have an extended solid solubility into the ternary system: (Mg2Ca) where Al substitute Mg in the binary compound Mg2Ca (Al2Ca) and (Al3Ca8) where Mg substitute Al in the binary compounds Al2Ca and Al3Ca8, respectively. Two morphologies of eutectic structure were observed in the micrographs and supported by solidification curves; a coarse and fine eutectic microstructures due to the existence of Al2Ca and Mg2Ca, respectively

  14. Silicon calorimetry for the SSC[ Superconducting Supercollider

    International Nuclear Information System (INIS)

    SSC experiments will rely heavily on their calorimeters. Silicon calorimetry, which has been introduced in recent years as a useful technology, has many attractive characteristics which may make it a viable option for consideration. The many attractive properties of silicon detectors are reviewed. The relevant present day applications of large areas of silicon detectors are summarize to illustrate the emerging use. The troublesome issue of radiation damage in a high luminosity environment like the SSC is considered with a summary of much of the recent new measurements which help clarify this situation. A discussion of the electronics and a possible mechanical configuration is presented, followed by a summary of the outstanding R and D issues. 31 refs., 11 figs., 3 tabs

  15. Isothermal calorimetry on enzymatic biodiesel production

    DEFF Research Database (Denmark)

    Fjerbæk, Lene

    2008-01-01

    information about effects taking place when using lipases immobilized on an inert carrier for transesterification of a triglyceride and an alcohol as for biodiesel production. The biodiesel is produced by rapeseed oil and methanol as well as ethanol and a commercial biocatalyst Novozym 435 from Novozymes...... containing a Candida Antarctica B lipase immobilized on an acrylic resin. The reaction investigated is characterized by immiscible liquids (oil, methanol, glycerol and biodiesel) and enzymes imm. on an inert carrier during reaction, which allows several effects to take place that during normal reaction...... conditions can not be elucidated. These effects have been observed with isothermal calorimetry bringing forth new information about the reaction of enzymes catalyzing transesterification. Enzymatic biodiesel production has until now not been investigated with isothermal microcalorimetry, but the results...

  16. Analog pipeline readout for ATLAS calorimetry

    International Nuclear Information System (INIS)

    This paper presents the design and prototype testing of an analog pipeline readout module suitable for readout of the LAr calorimetry at the large hadron collider. The design has been driven by the readout requirements of the ATLAS electromagnetic liquid argon calorimeter and the ATLAS trigger design parameters. The results indicate that an analog pipeline readout system meeting the ATLAS requirements can be built using our modules. The SCA-chip employed has resolution approaching 13-bits (using the full range of the SCA) and can achieve a 16-bit dynamic range using a dual-range scheme. The module is based on switched capacitor array chips. A brief description of the design of the pipeline controller development, that will enable the SCA readout system to run as a deadtimeless analog RAM, is also given. (orig.)

  17. Calorimetry studies on U-Cr alloys

    International Nuclear Information System (INIS)

    A calorimetric study of Uranium-Chromium system is of interest on both basic and applied fronts. With the advent of U-Pu-Zr alloy as the fuel, in combination with ferritic-martensitic steel as the cladding material, the metal fuelled fast reactors constitute the second major step in Indian nuclear power program. In such a context, a fundamental investigation on the high temperature phase stability of U-Cr alloys is of particular relevance in getting further insight in to the complex issue of the metallurgical compatibility of ferritic steels with metallic Uranium-Zirconium fuel. It may be added that following U-Fe, and U-Zr binaries, the U-Cr constitutes one of the important subsystems of the complex U-Zr-Pu-Fe- Cr-Mn-Si-V-Nb-C-N multinary system. In the current study, the results of calorimetry investigations on U, U-2, 3, 7, 15wt. % Cr alloys are presented

  18. Bipolar monolithic preamplifiers for SSC silicon calorimetry

    International Nuclear Information System (INIS)

    This paper describes preamplifiers designed specifically to address the requirements of silicon calorimetry for the Superconducting Super Collider (SSC). Eight different preamplifiers designed for detector capacitances ranging from 20 pF to 500 pF and operating temperatures from 25 degree C to -20 degree C are discussed. The preamplifiers were fabricated with two different high-frequency processes (one with the VTC, Inc. VJ900 process, seven with the Harris Semiconductor VHF Process). The different topologies and their features are discussed in addition to the design methodologies employed. The results for noise, power consumption, speed, and radiation damage effects as well as data for post-damage annealing are presented for the VTC process preamplifier. Simulations for the VHF Process circuits are presented. This work was funded through SSC Generic Detector funding, SSC Detector Subsystem funding, and the Oak Ridge National Laboratory (ORNL) Detector Center

  19. Fast Scanning Calorimetry Studies of Supercooled Liquids and Glasses

    Science.gov (United States)

    Bhattacharya, Deepanjan

    This dissertation is a compilation of research results of extensive Fast Scanning Calorimetry studies of two non-crystalline materials: Toluene and Water. Motivation for fundamental studies of non-crystalline phases, a brief overview of glassy materials and concepts and definitions related to them is provided in Chapter 1. Chapter 2 provides fundamentals and details of experimental apparata, experimental protocol and calibration procedure. Chapter 3 & 4 provides extensive studies of stable non-crystalline toluene films of micrometer and nanometer thicknesses grown by vapor deposition at distinct deposition rates and temperatures and probed by Fast Scanning Calorimetry. Fast scanning calorimetry is shown to be extremely sensitive to the structure of the vapor-deposited phase and was used to characterize simultaneously its kinetic stability and its thermodynamic properties. According to our analysis, transformation of vapor -deposited samples of toluene during heating with rates in excess 100,000 K/s follows the zero-order kinetics. The transformation rate correlates strongly with the initial enthalpy of the sample, which increases with the deposition rate according to sub-linear law. Analysis of the transformation kinetics of vapor deposited toluene films of various thicknesses reveal a sudden increase in the transformation rate for films thinner than 250 nm. The change in kinetics correlates with the surface roughness scale of the substrate, which is interpreted as evidence for kinetic anisotropy of the samples. We also show that out-of-equilibrium relaxation kinetics and possibly the enthalpy of vapor-deposited (VD) films of toluene are distinct from those of ordinary supercooled (OS) phase even when the deposition takes place at temperatures above the glass softening (Tg). The implications of these findings for the formation mechanism and structure of vapor deposited stable glasses are discussed. Chapter 5 and 6 provide detailed Fast Scanning Calorimetry studies

  20. Kinetic analysis by DSC of the cationic curing of mixtures of DGEBA and 6,6-dimethyl (4,8-dioxaspiro[2.5]octane-5,7-dione)

    International Nuclear Information System (INIS)

    The kinetics of the thermal cationic cure reaction of mixtures in different proportions of diglycidylether of bisphenol A (DGEBA) with 6,6-dimethyl (4,8-dioxaspiro[2.5]octane-5,7-dione) (MCP) initiated by ytterbium or lanthanum triflates or using a conventional initiator, BF3.MEA was investigated. The non-isothermal differential scanning calorimetry (DSC) experiments at a controlled heating rate was used for obtaining the kinetic parameters of the reactive systems. BF3.MEA and lanthanide triflates initiated curing systems follow a complete different kinetic model. Among lanthanide triflates, ytterbium is the most active initiator

  1. Kinetic analysis by DSC of the cationic curing of mixtures of DGEBA and 6,6-dimethyl (4,8-dioxaspiro[2.5]octane-5,7-dione)

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Lidia [Departament de Quimica Analitica i Quimica Organica, Universitat Rovira i Virgili, C/Marcelli Domingo s/n, 43007 Tarragona (Spain); Ramis, Xavier [Laboratori de Termodinamica, ETSEIB, Universitat Politecnica de Catalunya, Av. Diagonal 647, 08028 Barcelona (Spain); Salla, Josep Maria [Laboratori de Termodinamica, ETSEIB, Universitat Politecnica de Catalunya, Av. Diagonal 647, 08028 Barcelona (Spain)], E-mail: salla@mmt.upc.edu; Mantecon, Ana; Serra, Angels [Departament de Quimica Analitica i Quimica Organica, Universitat Rovira i Virgili, C/Marcelli Domingo s/n, 43007 Tarragona (Spain)

    2007-11-25

    The kinetics of the thermal cationic cure reaction of mixtures in different proportions of diglycidylether of bisphenol A (DGEBA) with 6,6-dimethyl (4,8-dioxaspiro[2.5]octane-5,7-dione) (MCP) initiated by ytterbium or lanthanum triflates or using a conventional initiator, BF{sub 3}.MEA was investigated. The non-isothermal differential scanning calorimetry (DSC) experiments at a controlled heating rate was used for obtaining the kinetic parameters of the reactive systems. BF{sub 3}.MEA and lanthanide triflates initiated curing systems follow a complete different kinetic model. Among lanthanide triflates, ytterbium is the most active initiator.

  2. Titration Calorimetry Standards and the Precision of Isothermal Titration Calorimetry Data

    OpenAIRE

    Daumantas Matulis; Jurgita Matulienė; Vilma Petrikaitė; Lina Baranauskienė

    2009-01-01

    Current Isothermal Titration Calorimetry (ITC) data in the literature have relatively high errors in the measured enthalpies of protein-ligand binding reactions. There is a need for universal validation standards for titration calorimeters. Several inorganic salt co-precipitation and buffer protonation reactions have been suggested as possible enthalpy standards. The performances of several commercial calorimeters, including the VP-ITC, ITC200, and Nano ITC-III, were validated using these sug...

  3. Calorimetry for ILC Experiments: CALICE Collaboration R&D

    OpenAIRE

    Bailey, D.S.; Collaboration, for the CALICE

    2008-01-01

    The CALICE Collaboration is carrying out research and development into calorimetry for a detector at the International Linear Collider (ILC). CALICE is investigating a range of technologies for both electromagnetic and hadronic calorimetry. An overview of the prototypes and selected test-beam results are presented.

  4. Excess heat capacity of the (Li1−xCax)F1+x liquid solution determined by differential scanning calorimetry and drop calorimetry

    International Nuclear Information System (INIS)

    Highlights: • The heat capacity of the (Li1−xCax)F1+x liquid solution was measured. • A procedure for DSC was developed to measure heat capacity of encapsulated samples. • A significant excess heat capacity of (Li1−xCax)F1+x liquid solution was observed. - Abstract: The work presents the measured heat capacity of the (Li1−xCax)F1+x liquid solution. Four samples with different compositions have been prepared and measured using a Differential Scanning Calorimeter. Since this technique was newly adopted for measuring encapsulated fluoride samples, some modifications were introduced in the standard configuration of the instrument and they are described in this work as well. For comparison one of the analysed composition (xCaF2 = 0.5) was also measured using drop calorimetry, which has been previously used for similar studies. The reliability of the results obtained was confirmed by the good agreement between the two techniques. Moreover, the excess heat capacity of the (Li1−xCax)F1+x liquid solution was derived and a strong deviation from the ideal behaviour was observed

  5. Evaluation of shrinkage temperature of bovine pericardium tissue for bioprosthetic heart valve application by differential scanning calorimetry and freeze-drying microscopy

    Directory of Open Access Journals (Sweden)

    Virgilio Tattini Jr

    2007-03-01

    Full Text Available Bovine pericardium bioprosthesis has become a commonly accepted device for heart valve replacement. Present practice relies on the measurement of shrinkage temperature, observed as a dramatic shortening of tissue length. Several reports in the last decade have utilized differential scanning calorimetry (DSC as an alternative method to determine the shrinkage temperature, which is accompanied by the absorption of heat, giving rise to an endothermic peak over the shrinkage temperature range of biological tissues. Usually, freeze-drying microscope is used to determine collapse temperature during the lyophilization of solutions. On this experiment we used this technique to study the shrinkage event. The aim of this work was to compare the results of shrinkage temperature obtained by DSC with the results obtained by freeze-drying microscopy. The results showed that both techniques provided excellent sensitivity and reproducibility, and gave information on the thermal shrinkage transition via the thermodynamical parameters inherent of each method.

  6. Current status of tritium calorimetry at TLK

    International Nuclear Information System (INIS)

    Inside a tritium facility, calorimetry is an important analytical method as it is the only reference method for accountancy (it is based on the measurement of the heat generated by the radioactive decay). Presently, at Tritium Laboratory Karlsruhe (TLK), 4 calorimeters are in operation, one of isothermal type and three of inertial guidance control type (IGC). The volume of the calorimeters varies between 0.5 and 20.6 liters. About two years ago we started an extensive work to improve our calorimeters with regard to reliability and precision. We were forced to upgrade 3 of our 4 calorimeters due to the outdated interfaces and software. This work involved creating new LabView programs driving the devices, re-tuning control loops and replacing obsolete hardware components. In this paper we give a review on the current performance of our calorimeters, comparing it to recently available devices from the market and in the literature. We also show some ideas for a next generation calorimeter based on experiences with our IGC calorimeters and other devices reported in the literature. (authors)

  7. Melting by temperature-modulated calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Wunderlich, B.; Okazaki, Iwao; Ishikiriyama, Kazuhiko; Boller, A. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemistry]|[Oak Ridge National Lab., TN (United States)

    1997-09-01

    Well-crystallized macromolecules melt irreversibly due to the need of molecular nucleation, while small molecules melt reversibly as long as crystal nuclei are present to assist crystallization. Furthermore, imperfect crystals of low-molar-mass polymers may have a sufficiently small region of metastability between crystallization and melting to show a reversing heat-flow component due to melting of poor crystals followed by crystallization of imperfect crystals which have insufficient time to perfect before the modulation switches to heating and melts the imperfect crystals. Many metals, in turn. melt sharply and reversibly as long as nuclei remain after melting for subsequent crystallization during the cooling cycle. Their analysis is complicated, however, due to thermal conductivity limitations of the calorimeters. Polymers of sufficiently high molar mass, finally, show a small amount of reversible. local melting that may be linked to partial melting of individual molecules. Experiments by temperature-modulated calorimetry and model calculations are presented. The samples measured included poly(ethylene terephthalate)s, poly(ethylene oxide)s, and indium. Two unsolved problems that arose from this research involve the origin of a high, seemingly stable, reversible heat capacity of polymers in the melting region, and a smoothing of melting and crystallization into a close-to-elliptical Lissajous figure in a heat-flow versus sample-temperature plot.

  8. Study of thermal decomposition of methyl ethyl ketone peroxide using DSC and simulation.

    Science.gov (United States)

    Tseng, Jo-Ming; Chang, Ying-Yu; Su, Teh-Sheng; Shu, Chi-Min

    2007-04-11

    Methyl ethyl ketone peroxide (MEKPO) is a typical organic peroxide with thermally unstable nature that has been broadly employed in the manufacturing process of acrylic resins, as a hardening agent for fiberglass-reinforced plastics, and as a curing agent for unsaturated polyester resins. The aim of this study was to identify the characteristics of MEKPO 31 wt.% while mixing with contaminants, such as H(2)SO(4), HCl, and NaCl under runaway conditions. To acquire the thermal runaway data, DSC and a simulation were used for thermal analysis. The results showed that the thermal decomposition of MEKPO and MEKPO+H(2)SO(4) follows two stages. The first one can be modeled by using an empirical nth order rate equation. The second stage can be modeled as autocatalytic. MEKPO+HCl and MEKPO+NaCl included two independent autocatalytic reactions. The decomposition of MEKPO in the presence of Cl- ions (added in MEKPO either in the form of HCl or NaCl) follows a significantly different path, an earlier decomposition "onset" temperature, higher amount of generated thermal power and smaller temperature of no return (T(NR)) and time to maximum rate (TMR) values. Simulations based on experimental data indicated that the effect of H(2)SO(4) was the most dangerous contaminant on MEKPO 31 wt.%. However, the impact of Cl ions was also important. It is therefore recommended that the means of fire fighting employed for this substance to be free of Cl-. PMID:16905247

  9. A DSC study on the effect of marination on the stability of skin collagen from chicken wings

    Directory of Open Access Journals (Sweden)

    Jolanta Tomaszewska-Gras

    2010-12-01

    Full Text Available   Background. Marination is a good method to enhance attractiveness of chicken wings, which are considered by consumers as least attractive. Sensory value of marinated wings is dependent largely on the flavour of skin, because they contain proportionally more skin than other carcass elements. Moreover, skin constitutes a natural barrier, which may facilitate or hinder the penetration of marinade components, depending on the conformation state of proteins it is composed of primarily collagen. The aim of the study was to investigate the effect of specific marinades on thermal stability of collagen – the main component of skin proteins using differential scanning calorimetry (DSC. Material and methods. Chicken wings were marinated using model marinades, marinades prepared according to original recipes and ready-to-use marinades used in industrial practice. Marinated skin samples were weighted (approx. 10 mg and analyzed by DSC. Heating rate was 5°C/min, within the range from 20 to 100°C. Results. In analyses using model marinades denaturation temperature (Tmax of collagen was reduced by approx. 3°C and enthalpy (ΔH was lowered by approx. 40%. An even bigger reduction of collagen denaturation temperature (by approx. 7°C and enthalpy ΔH (by approx. 48% was found after the application of marinades prepared following original recipes (W1, W2, W3. In turn, the application of model marinades containing NaCl and organic acids (acetic or citric resulted in stabilization of collagen, which was manifested by an increase of enthalpy (ΔH by approx. 50% (for marinade containing 2% citric acid. Conclusions. Temperature and enthalpy of collagen denaturation was dependent on type of marinade. The extent of collagen denaturation affects nutritional and sensory value. Considering that time and temperature of intensive heat treatment are important factors in the formation process of carcinogenic compounds i.e. heterocyclic aromatic amines, it bis

  10. Microphase separation in copolymers of hydrophilic PEG blocks and hydrophobic tyrosine-derived segments using simultaneous SAXS/WAXS/DSC.

    Science.gov (United States)

    Murthy, N S; Wang, W; Kohn, J

    2010-08-01

    Hydration- and temperature-induced microphase separations were investigated by simultaneous small- and wide-angle X-ray scattering (SAXS and WAXS) and differential scanning calorimetry (DSC) in a family of copolymers in which hydrophilic poly(ethylene glycol) (PEG) blocks are inserted randomly into a hydrophobic polymer made of either desaminotyrosyl-tyrosine ethyl ester (DTE) or iodinated I(2)DTE segments. Iodination of the tyrosine rings in I(2)DTE increased the X-ray contrast between the hydrophobic and hydrophilic segments in addition to facilitating the study of the effect of iodination on microphase separation. The formation of phase-separated, hydrated PEG domains is of considerable significance as it profoundly affects the polymer properties. The copolymers of DTE (or I(2)DTE) and PEG are a useful model system and the findings presented here may be applicable to other PEG-containing random copolymers as well. In copolymers of PEG and DTE and I(2)DTE, the presence of PEG depressed the glass transition temperature (T(g)) of the copolymer relative to the homopolymer, poly(DTE carbonate), and the DTE/ I(2)DTE segments hindered the crystallization of the PEG segments. In the dry state, at large PEG fractions (> 70 vol%), the PEG domains self-assembled into an ordered structure with 14-18 nm distance between the domains. These domains gave rise to a SAXS peak at all temperatures in the iodinated polymers, but only above the T(g) in non-iodinated polymers, due to the unexpected contrast- match between the crystalline PEG domains and the glassy DTE segments. Irrespective of whether PEG was crystalline or not, immersion of these copolymers in water resulted in the formation of hydrated PEG domains that were 10-20 nm apart. Since both water and the polymer chains must be mobile for the phase separation to occur, the PEG domains disappeared when the water froze, and reappeared as the ice began to melt. This transformation was reversible, and showed hysteresis as did

  11. Small-angle x-ray scattering and differential scanning calorimetry studies of DPPC multilamellar structures containing membranotropic agents of different chemical nature

    International Nuclear Information System (INIS)

    Multilamellar structures formed in DPPC/water/glycerol and DPPC/water/oxyethylated glycerol systems are studied by small-angle X-ray scattering (SAXS) and differential scanning calorimetry (DSC) methods. The effects of glycerol, oxyethylated glycerol, and other membranotropic agents (MTAs) on the lamellar repeat distance D are compared in gel, ripple, and high-temperature (Lα) liquid crystal phases of the hydrated phospholipids. It is noted that the introduction of MTAs could lead to different types of 'D vs. temperature' behavior in the Lα phase, which is correlated with changes in D caused by the introduction of these substances to the DPPC/water reference system

  12. Experimental study of the ternary Ag-Cu-In phase diagram

    International Nuclear Information System (INIS)

    The phase diagram of the Ag-Cu-In system was investigated using powder X-ray diffraction (XRD), differential scanning calorimetry (DSC) and electron probe microanalysis (EPMA). Two isothermal sections (at 510 and 607 deg. C) and 15 isopletic sections were studied. The results showed seven ternary peritectics, one ternary eutectic and one ternary metatectic. A complete reaction scheme was constructed, the valleys were drawn and the liquidus surfaces were derived from DSC data in the entire composition range.

  13. Experimental study of the ternary Ag-Cu-In phase diagram

    Energy Technology Data Exchange (ETDEWEB)

    Bahari, Zahra [Laboratoire de chimie physique et minerale, Faculte des sciences pharmaceutiques et biologiques, Universite Paris Descartes, avenue de l' Observatoire, 75006 Paris (France); Laboratoire de chimie du solide mineral (LCSM), Faculte des sciences, Universite Mohamed 1er, Route Sidi Maafa, B.P. 524, Oujda, Maroc (Morocco); Elgadi, Mohamed [Laboratoire de chimie du solide mineral (LCSM), Faculte des sciences, Universite Mohamed 1er, Route Sidi Maafa, B.P. 524, Oujda, Maroc (Morocco); Rivet, Jacques [Laboratoire de chimie physique et minerale, Faculte des sciences pharmaceutiques et biologiques, Universite Paris Descartes, avenue de l' Observatoire, 75006 Paris (France); Dugue, Jerome [Laboratoire de chimie physique et minerale, Faculte des sciences pharmaceutiques et biologiques, Universite Paris Descartes, avenue de l' Observatoire, 75006 Paris (France)], E-mail: jerome.dugue@univ-paris5.fr

    2009-05-27

    The phase diagram of the Ag-Cu-In system was investigated using powder X-ray diffraction (XRD), differential scanning calorimetry (DSC) and electron probe microanalysis (EPMA). Two isothermal sections (at 510 and 607 deg. C) and 15 isopletic sections were studied. The results showed seven ternary peritectics, one ternary eutectic and one ternary metatectic. A complete reaction scheme was constructed, the valleys were drawn and the liquidus surfaces were derived from DSC data in the entire composition range.

  14. Study of Liquid Argon Dopants for LHC Hadron Calorimetry

    CERN Multimedia

    2002-01-01

    Hadron calorimetry based on the Liquid Argon Ionisation Chamber technique is one of the choice techniques for LHC-experimentation. A systematic study of the effect of selected dopants on Liquid Argon (LAr) will be carried out with the aim to achieve an improvement on: \\item (i)~``Fast Liquid Argon'' search and study of dopants to increase the drift velocity. It has been already shown that CH&sub4. added at a fraction of one percent increases the drift velocity by a factor of two or more. \\item (ii)~``Compensated Liquid Argon'' search and study of dopants to increase the response to densely ionising particles, resulting in improved compensation, such as photosensitive dopants. \\end{enumerate}\\\\ \\\\ Monitoring of the parameters involved in understanding the response of a calorimeter is essential. In case of doped LAr, the charge yield, the non-saturated drift velocity and the electron lifetime in the liquid should be precisely and simultaneously monitored as they all vary with the level of dopant concentrati...

  15. Summary session of the Gas Sampling Calorimetry Workshop

    International Nuclear Information System (INIS)

    The summary session of the Gas Sampling Calorimetry Workshop was a review and discussion session. A number of questions were raised and briefly discussed. More extensive discussions of energy resolution formed the heart of the final session

  16. Application of adiabatic calorimetry to metal systems. Final report

    International Nuclear Information System (INIS)

    Research on the application of adiabatic calorimetry to metal systems is described. Investigations into formation of pearlite in steels, ferromagnetic effects, cold working and annealing, solid solution alloys, pure solid metals, and pure liquid metals, are briefly described

  17. Isothermal Calorimetry for Biological Applications in Food Science and Technology

    OpenAIRE

    Wadsö, Lars; Gomez, Federico

    2009-01-01

    All physical, chemical and biological processes produce heat and isothermal calorimetry is a general measurement technique to study all kinds of processes by the heat they produce. This paper gives several examples of studies of biological processes in the food area using isothermal calorimetry. It is for example shown how different unit operations influence respiration of vegetable tissue, how the kinetics of a fermentation process can be studied, and how spoilage processes can be followed f...

  18. Particle Flow Calorimetry and the PandoraPFA Algorithm

    OpenAIRE

    Thomson, M. A.

    2009-01-01

    The Particle Flow (PFlow) approach to calorimetry promises to deliver unprecedented jet energy resolution for experiments at future high energy colliders such as the proposed International Linear Collider (ILC). This paper describes the PandoraPFA particle flow algorithm which is then used to perform the first systematic study of the potential of high granularity PFlow calorimetry. For simulated events in the ILD detector concept, a jet energy resolution of sigma_E/E < 3.8 % is achieved for 4...

  19. Continuing Studies on Lead/Scintillating Fibres Calorimetry (LFC)

    CERN Multimedia

    2002-01-01

    Starting from the results obtained in the framework of the LAA Project~2B, we propose a continuation of the R&D on lead/scintillating fibres calorimetry (``spaghetti calorimetry''), including further tests on the old calorimeter prototypes and the construction and testing of new prototypes. The main results we pursue concern the performances of a projective calorimeter built with new, cheaper, techniques and the radiation hardness of the scintillating fibres, the optimization of a preshower detector system is also studied.

  20. Differential scanning calorimetry of superelastic Nitinol for tunable cymbal transducers

    OpenAIRE

    Feeney, Andrew; Lucas, Margaret

    2015-01-01

    Recent research has shown that estimations of the transformation temperatures of superelastic Nitinol using differential scanning calorimetry can be inaccurate, in part, due to the residual stress in the material. Superelastic Nitinol is selected as the end-cap material in a tunable cymbal transducer. The differential scanning calorimetry accuracy is initially probed by comparing transformation temperature measurements of cold-worked superelastic Nitinol with the same material after an anneal...

  1. Thermal characterization of starch-water system by photopyroelectric technique and adiabatic scanning calorimetry

    Science.gov (United States)

    Cruz-Orea, A.; Bentefour, E. H.; Jamée, P.; Chirtoc, M.; Glorieux, C.; Pitsi, G.; Thoen, J.

    2003-01-01

    Starch is one of the most important carbohydrate sources in human nutrition. For the thermal analysis of starch, techniques such as differential scanning calorimetry have been extensively used. As an alternative, we have applied a photopyroelectric (PPE) configuration and adiabatic scanning calorimetry (ASC) to study the thermal properties of starch-water systems. For this study we used nixtamalized corn flour and potato starch with different quantities of distilled water, in order to obtain samples with different moisture content. By using PPE and ASC methods we have measured, for each technique separately, the heat capacity by unit volume (ρcp) at room temperature for a corn flour sample at 90% moisture. The obtained values agree within experimental uncertainty. By using these techniques we also studied the thermal behavior of potato starch, at 80% moisture, in the temperature range where phase transitions occur. In this case the PPE signal phase could be used as a sensitive and versatile monitor for phase transitions.

  2. Methodology of hot nucleus calorimetry and thermometry produced by nuclear reactions around Fermi energies; Methodologie de la calorimetrie et de la thermometrie des noyaux chauds formes lors de collisions nucleaires aux energies de Fermi

    Energy Technology Data Exchange (ETDEWEB)

    Vient, E

    2006-12-15

    This work deals with the calorimetry and thermometry of hot nuclei produced in collisions Xe + Sn between 25 and 100 MeV/u. The apparatus for hot nucleus physical characterization is the 4{pi} detector array Indra. This study was made by using the event generators Gemini, Simon and Hipse and a data-processing filter simulating the complete operation of the multi-detector. The first chapter presents the different ways of producing hot nuclei. In the second and third chapters, the author presents a critical methodological study of calorimetry and thermometry applied to hot nuclei, different methods are reviewed, their accuracy and application range are assessed. All the calorimetry methods rely on the assumption that we are able to discriminate decay products of the hot nucleus from evaporated particles. In the fourth chapter, the author gives some ways of improving calorimetry characterization of the hot nucleus. An alternative method of calorimetry is proposed in the fifth chapter, this method is based on the experimental determination of an evaporation probability that is deduced from the physical characteristics of the particles present in a restricted domain of the space of velocities.

  3. DSC: software tool for simulation-based design of control strategies applied to wastewater treatment plants.

    Science.gov (United States)

    Ruano, M V; Ribes, J; Seco, A; Ferrer, J

    2011-01-01

    This paper presents a computer tool called DSC (Simulation based Controllers Design) that enables an easy design of control systems and strategies applied to wastewater treatment plants. Although the control systems are developed and evaluated by simulation, this tool aims to facilitate the direct implementation of the designed control system to the PC of the full-scale WWTP (wastewater treatment plants). The designed control system can be programmed in a dedicated control application and can be connected to either the simulation software or the SCADA of the plant. To this end, the developed DSC incorporates an OPC server (OLE for process control) which facilitates an open-standard communication protocol for different industrial process applications. The potential capabilities of the DSC tool are illustrated through the example of a full-scale application. An aeration control system applied to a nutrient removing WWTP was designed, tuned and evaluated with the DSC tool before its implementation in the full scale plant. The control parameters obtained by simulation were suitable for the full scale plant with only few modifications to improve the control performance. With the DSC tool, the control systems performance can be easily evaluated by simulation. Once developed and tuned by simulation, the control systems can be directly applied to the full-scale WWTP. PMID:21330730

  4. Energy expenditure in critically ill patients estimated by population-based equations, indirect calorimetry and CO2-based indirect calorimetry

    OpenAIRE

    Rousing, Mark Lillelund; Hahn-Pedersen, Mie Hviid; Andreassen, Steen; Pielmeier, Ulrike; Preiser, Jean-Charles

    2016-01-01

    Background Indirect calorimetry (IC) is the reference method for measurement of energy expenditure (EE) in mechanically ventilated critically ill patients. When IC is unavailable, EE can be calculated by predictive equations or by VCO2-based calorimetry. This study compares the bias, quality and accuracy of these methods. Methods EE was determined by IC over a 30-min period in patients from a mixed medical/postsurgical intensive care unit and compared to seven predictive equations and to VCO2...

  5. DMSO-induced dehydration of DPPC membranes studied by x-ray diffraction, small angle neutron scattering and calorimetry

    International Nuclear Information System (INIS)

    The properties of dimethyl sulfoxide (DMSO), a cryoprotector well known for its biological and therapeutic applications, were investigated on lipid membranes by x-ray diffraction, differential scanning calorimetry (DSC) and small angle neutron scattering (SANS). The DSC study of water freezing and melting of ice was performed in the ternary system which consists of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC)/DMSO/water system. The influence of DMSO on the DPPC membrane structure was established in the excess of solvent in the region of DMSO mole fraction from 0.0 to 1.0. The methods applied demonstrated the differences in the membrane structure in three sub-regions of DMSO mole fraction (XDMSO) from 0.0 to 0.3 for the first, from 0.3 to 0.9 for the second, and from 0.9 to 1.0 for the third sub-region. The results for 0.0 ≤ XDMSO ≤ 0.3 can be explained in the framework of DMSO-induced dehydration of intermembrane space

  6. Study of phase transformations of Fe-Cr-C system using the technique of differential scanning calorimetry

    International Nuclear Information System (INIS)

    The family of 9% Cr-1% Mo steels has been considered by The Generation IV International Forum as candidate materials for the construction of these prospective advanced nuclear reactors. A simple system related with these steels is the Fe-Cr-C system. In this work, a laboratory made Fe-10% Cr-0,1% C alloy has been studied. Particularly, the effect of the cooling rate on the transformations that take place when the alloy is cooled from the austenitic field was analyzed. To perform this analysis two techniques have been used: The differential scanning calorimetry (DSC) and the scanning electron microscopy (SEM). Different cooling rates of 4, 10, 50 and 90 °C/min were tested in the DSC and the resulting microstructures were observed by SEM. At the rates of 50 and 90 °C/min the cooling treatment produced a martensitic structure. Contrarily, cooling at a rate of 4 °C/min produced a microstructure consisting mainly of ferrite-pearlite with a low fraction of martensite. In the heating step which followed the cooling step, the magnetic transformation is well resolved as a broad peak which presents a maximum at 753 ± 1 °C for all the cooling rates. (author)

  7. Thermal and structural behavior of dioctadecyldimethylammonium bromide dispersions studied by differential scanning calorimetry and X-ray scattering.

    Directory of Open Access Journals (Sweden)

    Eloi Feitosa

    Full Text Available Dioctadecyldimethylammonium bromide (DODAB is a double chain cationic lipid, which assembles as bilayer structures in aqueous solution. The precise structures formed depend on, e.g., lipid concentration and temperature. We here combine differential scanning calorimetry (DSC and X-ray scattering (SAXS and WAXS to investigate the thermal and structural behavior of up to 120 mM DODAB in water within the temperature range 1-70 °C. Below 1 mM, this system is dominated by unilamellar vesicles (ULVs. Between 1 and 65 mM, ULVs and multilamellar structures (MLSs co-exist, while above 65 mM, the MLSs are the preferred structure. Depending on temperature, DSC and X-ray data show that the vesicles can be either in the subgel (SG, gel, or liquid crystalline (LC state, while the MLSs (with lattice distance d = 36.7 Å consist of interdigitated lamellae in the SG state, and ULVs in the LC state (no Bragg peak. Critical temperatures related to the thermal transitions of these bilayer structures obtained in the heating and cooling modes are reported, together with the corresponding transition enthalpies.

  8. Assessing Mixing Quality of a Copovidone-TPGS Hot Melt Extrusion Process with Atomic Force Microscopy and Differential Scanning Calorimetry.

    Science.gov (United States)

    Lamm, Matthew S; DiNunzio, James; Khawaja, Nazia N; Crocker, Louis S; Pecora, Anthony

    2016-02-01

    Atomic force microscopy (AFM) and modulated differential scanning calorimetry (mDSC) were used to evaluate the extent of mixing of a hot melt extrusion process for producing solid dispersions of copovidone and D-α-tocopherol polyethylene glycol 1000 succinate (TPGS 1000). In addition to composition, extrusion process parameters of screw speed and thermal quench rate were varied. The data indicated that for 10% TPGS and 300 rpm screw speed, the mixing was insufficient to yield a single-phase amorphous material. AFM images of the extrudate cross section for air-cooled material indicate round domains 200 to 700 nm in diameter without any observed alignment resulting from the extrusion whereas domains in extrudate subjected to chilled rolls were elliptical in shape with uniform orientation. Thermal analysis indicated that the domains were predominantly semi-crystalline TPGS. For 10% TPGS and 600 rpm screw speed, AFM and mDSC data were consistent with that of a single-phase amorphous material for both thermal quench rates examined. When the TPGS concentration was reduced to 5%, a single-phase amorphous material was achieved for all conditions even the slowest screw speed studied (150 rpm). PMID:26283196

  9. Measurements at the RA Reactor related to the VISA-2 project - Part 4, Calorimetry and chemical dosimetry of the new partly filled RA reactor core

    International Nuclear Information System (INIS)

    This report contains the results of values of chemical and calorimetry measurements of absorbed doses in the experimental channels VK-5, VK-9, GF-34 and fuel channels (0706 and 0607) of the Ra reactor. Calorimetry measurements were during reactor operation at 900 kW or 1 MW power, dependent on the type of samples in the calorimeters. For the chemical measurements the power was kept at 500 kW

  10. Differential scanning calorimetry study--assessing the influence of composition of vegetable oils on oxidation.

    Science.gov (United States)

    Qi, Baokun; Zhang, Qiaozhi; Sui, Xiaonan; Wang, Zhongjiang; Li, Yang; Jiang, Lianzhou

    2016-03-01

    The thermal oxidation of eight different vegetable oils was studied using differential scanning calorimetry (DSC) under non-isothermal conditions at five different heating rates (5, 7.5, 10, 12.5, and 15°C/min), in a temperature range of 100-400°C. For all oils, the activation energy (Ea) values at Tp were smaller than that at Ts and Ton. Among all the oils, refined palm oil (RPO) exhibited the highest Ea values, 126.06kJ/mol at Ts, 134.7kJ/mol at Ton, and 91.88kJ/mol at Tp. The Ea and reaction rate constant (k) values at Ts, Ton, and Tp were further correlated with oil compositions (fatty acids and triacylglycerols) using Pearson correlation analysis. The rate constant (k) and Ea of all oils exhibited varying correlations with FAs and TAGs, indicating that the thermal oxidation behaviors were affected by oil compositions. PMID:26471598

  11. Study of temperature dependent zirconium silicide phases in Zr/Si structure by differential scanning calorimetry

    International Nuclear Information System (INIS)

    The differential scanning calorimetry (DSC) technique is employed to study the formation of different silicide compounds of Zr thin-film deposited on a 100 μm-thick Si (1 0 0) substrate by dc sputtering. A detailed analysis shows that silicide layers start growing at  ∼246 °C that changes to stable ZrSi2 at 627 °C via some compounds with different stoichiometric ratios of Zr and Si. It is further observed that oxygen starts reacting with Zr at  ∼540 °C but a stoichiometric ZrO2 film is formed after complete consumption of Zr metal at 857 °C. A further rise in temperature changes a part of ZrSi2 to Zr-Silicate. The synchrotron radiation-based grazing incidence x-ray diffraction and x-ray photoelectron spectroscopy studies also corroborate the above findings. Atomic force microscopy is also carried out on the samples. It is evident from the observations that an intermixing and nucleation of Zr and Si occur at lower temperature prior to the formation of the interfacial silicate layer. Zr-Silicate formation takes place only at a higher temperature. (paper)

  12. Contribution of modulated DSc to study the thermal behaviour of PET films drawn in hot water

    International Nuclear Information System (INIS)

    PET films uni-axially drawn in hot water are studied by means of conventional DSc and modulated DSc. The glass transition is studied by modulated DSc which allows access to the values of the glass transition temperature Tg and the variations of δ Cp = Cp1-Cpg (difference between thermal capacity in the liquid-like and glassy states at T = Tg). Variations of Tg with the water content (which act as plasticizer) and with the drawing (which rigidifies the amorphous phase) are discussed in regard to the structure engaged in these materials. The variations of δ Cp are also interpreted with the help of a three phase model and a strong-fragile glass former liquid concept. We show that the fragility of the medium increases by the conjugated effects of deformation and water as soon as a strain induced crystalline phase is obtained, and it decreases drastically when the rigid amorphous phase occurs. (author)

  13. Calorimetric sensitivity and thermal resolution of a novel miniaturized ceramic DSC chip in LTCC technology

    Energy Technology Data Exchange (ETDEWEB)

    Missal, Wjatscheslaw, E-mail: wmissal@gmx.net [Department of Functional Materials, University of Bayreuth, 95440 Bayreuth (Germany); Kita, Jaroslaw [Department of Functional Materials, University of Bayreuth, 95440 Bayreuth (Germany); Wappler, Eberhard [wsk Mess- und Datentechnik GmbH, Gueterbahnhofstr. 1, 63450 Hanau (Germany); Bechtold, Franz [VIA electronic GmbH, Robert-Friese-Str. 3, 07629 Hermsdorf (Germany); Moos, Ralf [Department of Functional Materials, University of Bayreuth, 95440 Bayreuth (Germany)

    2012-09-10

    Highlights: Black-Right-Pointing-Pointer Unique vertical design of a DSC device manufactured in the low-cost LTCC technology and therefore capable of one-way use. Black-Right-Pointing-Pointer Fully functional DSC device with a size of only 1.5 mm Multiplication-Sign 11 mm Multiplication-Sign 39 mm enabling very low power consumption. Black-Right-Pointing-Pointer Comparable measurement performance as conventional DSC whilst also suitable for mobile thermal analysis. Black-Right-Pointing-Pointer Thermal resolution is 0.12 (TAWN test). Repeatability of the peak area is within 0.3% for indium samples. Black-Right-Pointing-Pointer Calorimetric sensitivity: linear with regard to temperature and independent from sample mass and heating rate in wide ranges. - Abstract: The calorimetric properties of a novel miniaturized ceramic differential scanning calorimeter device (MC-DSC) with integrated heater and crucible are presented. All features of a conventional DSC apparatus (including oven) are integrated into this DSC device of the size 11 mm Multiplication-Sign 39 mm Multiplication-Sign 1.5 mm. The MC-DSC device is suitable for one-way use, since it is fully manufactured in the low-cost planar low temperature co-fired ceramics technology. First characterization of this device is performed using indium, tin and zinc samples. The calorimetric sensitivity at 156.6 Degree-Sign C is 0.24 J/ Degree-Sign C s. It depends linearly on temperature in the range of at least 150 Degree-Sign C and 420 Degree-Sign C. The calorimetric sensitivity is constant up to an enthalpy of fusion of at least {Delta}H = 750 mJ (at 156.6 Degree-Sign C). The thermal analysis of indium in direct contact to the crucible of the chip even reveals a constant calorimetric sensitivity up to an enthalpy of fusion of at least {Delta}H = 1000 mJ. The repeatability of the peak area is within {+-}0.3% (11 mg indium, 10 measurements). The thermal resolution determined using 4,4 Prime -azoxyanisole under TAWN test

  14. Influence of benzene on the Ni3Fe nanocrystalline compound formation by wet mechanical alloying: An investigation combining DSC, X-ray diffraction, mass and IR spectrometries

    International Nuclear Information System (INIS)

    Research highlights: → Influence of benzene (PCA) used in wet MA on the powder properties is studied. → Nature of exothermic peak, linked to benzene presence on the particles wet milled. → Adsorbed benzene on the particles during wet milling is decomposed by annealing. → IR and TG-MS studies showed that CO2, CO and C are the main fragments obtained. - Abstract: Nanocrystalline Ni3Fe powders were obtained via wet mechanical alloying using benzene as surfactant. The differential scanning calorimetry (DSC) measurements showed the presence of an exothermic peak which does not correspond to any phase transformation or phase formation as was proved by X-ray diffraction measurements. The exothermic peak was observed neither for the dry milled samples nor for the wet milled and subsequently annealed powders at 350 deg. C for 4 h. The infra-red (IR) spectra registered for the wet milled samples showed a series of vibration bands corresponding to C6H6 and also to a series of fragments resulting from benzene decomposition. The results obtained by IR investigation were confirmed by thermogravimetry and mass spectrometry (TG + MS) investigations. The main fragments resulting from the benzene decomposition on the surface of the nanocrystalline Ni3Fe powders are: CO2, CO and C. The evolution of the particle size distribution versus the milling time has been determined for the wet mechanical milling process of nanocrystalline Ni3Fe powders. The DSC analysis reveals a displacement of the exothermic peak onset towards lower temperatures and an increase of the surface of this peak attributed to the changes in the particles specific surface and to the quantity of benzene added in the milling experiments.

  15. Liquid Argon Calorimetry with LHC-Performance Specifications

    CERN Multimedia

    2002-01-01

    % RD-3 Liquid Argon Calorimetry with LHC-Performance Specifications \\\\ \\\\Good electromagnetic and hadronic calorimetry will play a central role in an LHC detector. Among the techniques used so far, or under development, the liquid argon sampling calorimetry offers high radiation resistence, good energy resolution (electromagnetic and hadronic), excellent calibration stability and response uniformity. Its rate capabilities, however, do not yet match the requirements for LHC. \\\\ \\\\The aim of this proposal is to improve the technique in such a way that high granularity, good hermiticity and adequate rate capabilities are obtained, without compromising the above mentioned properties. To reach this goal, we propose to use a novel structure, the $^{\\prime\\prime}$accordion$^{\\prime\\prime}$, coupled to fast preamplifiers working at liquid argon temperature. Converter and readout electrodes are no longer planar and perpendicular to particles, as usual, but instead they are wiggled around a plane containing particles. ...

  16. Performance of Particle Flow Calorimetry at CLIC

    CERN Document Server

    Marshall, J.S.; Thomson, M.A.

    2013-01-01

    The experimental conditions at CLIC are also significantly more challenging than those at previous electron-positron colliders, with increased levels of beam-induced backgrounds combined with a bunch spacing of only 0.5 ns. This paper describes the modifications made to the PandoraPFA particle flow algorithm to improve the jet energy reconstruction for jet energies above 250 GeV. It then introduces a combination of timing and pT cuts that can be applied to reconstructed particles in order to significantly reduce the background. A systematic study is...

  17. Experimental study on thermo-mechanical properties of Polymer Modified Mortar

    International Nuclear Information System (INIS)

    Highlights: • We studied thermal and mechanical properties of ordinary and Polymer Modified Mortars. • For ordinary and polymer samples with different contents of Portland cement were used. • XDM, DSC and SEM were conducted to examine the interaction of the polymer mortars used. • Real improvement of the polymer mortars thermal properties was observed in comparison with ordinary ones. • Decrease of the mechanical strength of polymer mortars was observed when HDPE is added. - Abstract: This paper presents the results of an experimental program devoted to the study of Polymer Modified Mortars’ (PMM) thermal conductivity, thermal diffusivity and calorific capacity at different temperatures and compressive and flexural strengths at room-temperature. For this purpose, Ordinary Mortar (OM) and PMM samples with different contents and through partial substitution of Portland cement were prepared. A real improvement of the PMM thermal properties was observed in comparison with those of OM despite the decrease of mechanical strength. X-rays Diffract Meter (XDM), Differential Scanning Calorimetry (DSC) and Scanning Electron Microscope (SEM) were also conducted to show the interaction of the polymer material considered

  18. Combined experimental and density functional theory studies of an organic-inorganic hybrid perovskite.

    Science.gov (United States)

    Kassou, S; El-Mrabet, R; Kaiba, A; Guionneau, P; Belaaraj, A

    2016-04-14

    Single crystals of [C6H5-C2H4-NH3]2ZnCl4 were obtained by slow evaporation at room temperature. Single-Crystal X-Ray Diffraction (SCXRD), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA) and UV-Visible spectroscopy were used to characterize the crystal structure, and thermal and optical properties, respectively. At 293 K, PEA-ZnCl4 crystallizes in a monoclinic unit-cell in the P21/c space group a = 7.449(2) Å, b = 24.670(3) Å, c = 11.187(2) Å and β = 91.762(5)°, V = 2054.8(2) Å(3) and Z = 4. The DSC and TGA analyses show respectively the presence of two first order reversible phase transitions and a sample thermal stability below 541 K. The optical study reveals that the compound undergoes a direct optical transition and an energy gap about of Eg = 4.46 eV. In parallel, ab initio DFT calculations are performed to study the electronic band structure, to examine electronic density and to calculate the gap energy value. The calculated values are in good agreement with the experimental data. PMID:26979598

  19. Evaluation of the quasi-isothermal method of modulated DSC for heat capacity measurement

    International Nuclear Information System (INIS)

    Heat capacity measurements were carried out on ThO2 by Modulated Differential Scanning Calorimetry (MDSC) using quasi-isothermal method in the temperature range 323-723 K. The highest accuracy of the heat capacity data obtained by this method was ± 2-3% which is much lower than that reported in the literature. (author)

  20. Determination of Energy Characteristic and Microporous Volume by Immersion Calorimetry in Carbon Monoliths

    OpenAIRE

    Moreno-Piraján, Juan Carlos; Giraldo, Liliana; Vargas, Diana P.

    2012-01-01

    Activated carbon monoliths disc and honeycomb type were prepared by chemical activation of coconut shell with zinc chloride at different concentrations, without using a binder. The structures were characterized by N2 adsorption at 77 K and immersion calorimetry into benzene. The experimental results showed that the activation with zinc chloride produces a wide microporous development, with micropore volume between 0,38 and 0,79 cm3g-1, apparent BET surface area between 725 and 1523 m2g-1 and ...

  1. The thermodynamic stability of the three isomers of methoxybenzamide: An experimental and computational study

    International Nuclear Information System (INIS)

    Highlights: • Vapour pressures of the crystalline methoxybenzamides were measured. • Enthalpies and entropies of sublimation and combustion were determined. • Temperature and enthalpy of fusion were determined using DSC. • Enthalpies and standard Gibbs free energies of formation and isomerization are presented. • Gas-phase enthalpies of formation were estimated at the G3 and G4 levels. - Abstract: Thermodynamic properties of ortho, meta and para methoxybenzamides were determined using the Knudsen effusion method and calorimetric experiments as well as computational approaches. The vapour pressure of the crystalline phase of the three isomers was measured and values of the standard (po = 0.1 MPa) molar enthalpy, Gibbs energy and entropy of sublimation, at T = 298.15 K, were derived. Static bomb combustion calorimetry was used to measure the standard molar enthalpies of combustion from which the standard molar enthalpies of formation in the crystalline state, at T = 298.15 K, were derived. Together with the standard molar enthalpies of sublimation, these results yielded the standard molar enthalpies of formation in gaseous phase of the three isomers. The standard Gibbs energies of formation in crystalline and gaseous phases were also derived and used to differentiate the thermodynamic stability of the three isomers. Moreover, differential scanning calorimetry analysis enabled determination of the temperature and molar enthalpies of fusion of the studied compounds. Gas-phase enthalpies of formation of the three compounds were estimated computationally at the G3 and G4 levels of theory and compared with the experimental results

  2. Optimization of crystals for applications in dual-readout calorimetry

    Czech Academy of Sciences Publication Activity Database

    Akchurin, N.; Bedeschi, F.; Cardini, A.; Carosi, R.; Ciapetti, G.; Fasoli, M.; Ferrari, R.; Franchino, S.; Fraternali, M.; Gaudio, G.; Hauptman, J.; Incagli, M.; Lacava, F.; La Rotonda, L.; Lee, S.; Livan, M.; Meoni, E.; Nikl, Martin; Pinci, D.; Policicchio, A.; Popescu, S.; Scuri, F.; Sill, A.; Susinno, G.; Vandelli, W.; Vedda, A.; Venturelli, T.; Voena, C.; Volobouev, I.; Wigmans, R.

    2010-01-01

    Roč. 621, 1-3 (2010), 212-221. ISSN 0168-9002 Institutional research plan: CEZ:AV0Z10100521 Keywords : calorimetry * Cherenkov light * High-Z scintillating crystals Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.142, year: 2010

  3. Warm-up calorimetry of Dewar-Detector Assemblies

    Science.gov (United States)

    Veprik, A.; Shlomovich, B.; Tuito, A.

    2015-12-01

    Boil-off isothermal calorimetry of Dewar-Detector Assemblies (DDA) is a routine part of their Acceptance Testing Procedure. In this approach, the cryogenic liquid coolant (typically LN2) is allowed to naturally boil-off from the Dewar well to the atmosphere through a mass flow meter; the parasitic heat load is then evaluated as the product of the latent heat of vaporization and the "last drop" boil-off rate. An inherent major limitation of this technique is that it may be performed only at the fixed boiling temperature of the chosen liquid coolant. A further drawback is related to the explosive nature of "last drop" boiling, manifesting itself as an uneven flow rate. This especially holds true for advanced High Operational Temperature Dewar-Detector Assemblies, typically featuring short cold fingers and working at 150 K and above. In this work, we adapt the well-known technique of dual-slope calorimetry and show how accurate heat load evaluation may be performed by comparing the slopes of the warm-up thermal transients under different trial added heat loads. Because of the simplicity, accuracy and ability to perform calorimetry literally at any temperature of interest, this technique shows good potential for replacing traditional boil-off calorimetry.

  4. Preparation of Solid Derivatives by Differential Scanning Calorimetry.

    Science.gov (United States)

    Crandall, E. W.; Pennington, Maxine

    1980-01-01

    Describes the preparation of selected aldehydes and ketones, alcohols, amines, phenols, haloalkanes, and tertiaryamines by differential scanning calorimetry. Technique is advantageous because formation of the reaction product occurs and the melting point of the product is obtained on the same sample in a short time with no additional purification…

  5. Historical roots and development of thermal analysis and calorimetry

    Czech Academy of Sciences Publication Activity Database

    Šesták, J.; Hubík, Pavel; Mareš, Jiří J.

    Dodrecht: Springer, 2011 - (Šesták, J.; Mareš, J.; Hubík, P.), s. 347-370 ISBN 978-90-481-2881-5 Institutional research plan: CEZ:AV0Z10100521 Keywords : thermal analysis * calorimetry * history * Carnot ideas * personalities * DTA * ICTA Subject RIV: BM - Solid Matter Physics ; Magnetism

  6. DSC and optical studies on BaO-Li2O-B2O3-CuO glass system

    Science.gov (United States)

    Bhogi, Ashok; Kumar, R. Vijaya; Ahmmad, Shaik Kareem; Kistaiah, P.

    2016-05-01

    Glasses with composition 15BaO-25Li2O-(60-x)B2O3 -xCuO (x= 0, 0.2, 0.4, 0.6, 0.8 and 1 mol%) were prepared by the conventional melt quenching technique. These glasses were characterized using X-ray diffraction (XRD), differential scanning calorimetry (DSC) and density measurements. Optical absorption studies were carried out as a function of copper ion concentration. The optical absorption spectra of studied glasses containing copper oxide exhibit a single broad band around 761nm which has been assigned to the 2B1g→2B2g transition. From these studies, the variations in the values of glass transition temperature (Tg) have been observed. The fundamental absorption edge has been determined from the optical absorption spectra. The values of optical band gap and Urbach energy were determined with increase in concentration of CuO. The variations in density, glass transition temperature, optical band gap and Urbach energy with CuO content have been discussed in terms of changes in the glass structure. The analysis of these results indicated that copper ions mostly exist in Cu2+ state in these glasses when the concentration of CuO ≤ 0.8 mol% and above this concentration copper ions seem to subsist in Cu1+ state.

  7. Microwave curing of initially compatible epoxy–poly(ethylene terephthalate) blends: DSC kinetic study and nano-structure analysis{sup ☆}

    Energy Technology Data Exchange (ETDEWEB)

    Zvetkov, V.L., E-mail: zvetval@yahoo.com; Simeonova-Ivanova, E.; Djoumaliisky, S.

    2014-11-10

    Graphical abstract: The curves proposed to tabulate the curing regime in microwave field. - Highlights: • The monitoring of the curing process in microwave field is the aim of the study. • We consider an approach to estimate the curing regime in microwave field. • We present physical evidences for obtaining nano-modified epoxy composites. - Abstract: Poly(ethylene terephthalate), PET, dissolved in diglycidyl ether of bisphenol-A epoxy resins, DGEBA, is used as a toughening modifier. Two DGEBA resins in the presence of PET have been cured with the aid of diaminodiphenyl sulfone, DDS, in stoichiometric proportion. The curing process of the system DGEBA with DDS, in the presence of PET in particular, is monitored applying differential scanning calorimetry, DSC, in isothermal mode. The curing data are used to estimate the temperature regime in a microwave, MW, cavity. Physical confirmations for obtaining sub-micro phase separated DGEBA–DDS–PET composites and, in turn, for efficient modifying of the epoxy phase, have been discussed.

  8. Thermal degradation of ligno-cellulosic fuels: DSC and TGA studies

    OpenAIRE

    Leroy, Valérie; Cancellieri, Dominique; Leoni, Eric

    2008-01-01

    International audience The scope of this work was to show the utility of thermal analysis and calorimetric experiments to study the thermal oxidative degradation of Mediterranean scrubs. We investigated the thermal degradation of four species; DSC and TGA were used under air sweeping to record oxidative reactions in dynamic conditions. Heat released and mass loss are important data to be measured for wildland fires modelling purpose and fire hazard studies on ligno-cellulosic fuels. Around...

  9. Nucleation activity of glass fibers towards iPP evaluated by DSC and polarizing light microscopy

    OpenAIRE

    Janevski, Aco; Bogoeva-Gaceva, Gordana; Mader, Edit

    2001-01-01

    Nucleation activity of unsized and differently sized glass fibers during the crystallization of polypropylene from melt was investigated by polarizing light microscopy and DSC. Depending on the type of surface treatment, glass fibers were shown to exhibit different nucleating effects, evaluated by induction time of crystallization, crystallization onset temperature as well as half-time of crystallization in model composites with 50% wt glass fibers. Predominant nucleation activity was found f...

  10. DSC and TMDSC studies on glass transition temperature of alkali rare earth metaphosphate glasses

    Czech Academy of Sciences Publication Activity Database

    Rodová, Miroslava; Brožek, J.; Nitsch, Karel

    Praha : Czechoslovak Association for Crystal Growth (CSACG), 2012 - (Kožíšek, Z.; Nitsch, K.). s. 60-60 ISBN 978-80-260-2357-9. [Joint Seminar – Development of materials science in research and education /22./. 03.09.2012-07.09.2012, Lednice] R&D Projects: GA AV ČR KAN300100802 Institutional research plan: CEZ:AV0Z10100521 Keywords : DSC * TMDSC * glass transition temperature Subject RIV: BM - Solid Matter Physics ; Magnetism

  11. Differential Scanning Calorimetry and Evolved Gas Analysis of Hydromagnesite

    Science.gov (United States)

    Lauer, H. V., Jr.; Golden, D. C.; Ming, Douglas W.; Boynton, W. V.

    1999-01-01

    Volatile-bearing minerals (e.g., Fe-oxyhydroxides, phyllosilicates, carbonates and sulfates) may be important phases on the surface of Mars. In order to characterize these phases the Thermal and Evolved Gas Analyzer (TEGA) flying on the Mars'98 lander will perform analyses on surface samples from Mars. Hydromagnesite [Mg5(CO3)4(OH)2.4H2O] is considered a good standard mineral to examine as a Mars soil analog component because it evolves both H2O and CO2 at temperatures between 0 and 600 C. Our aim here is to interpret the DSC signature of hydromagnesite under ambient pressure and 20 sccm N2 flow in the range 25 to 600 C. The DSC curve for hydromagnesite under the above conditions consists of three endothermic peaks at temperatures 296, 426, and 548 and one sharp exotherm at 511 C. X-ray analysis of the sample at different stop temperatures suggested that the exotherm corresponded with the formation of crystalline magnesite. The first endotherm was due to dehydration of hydromagnesite, and then the second one was due to the decomposition of carbonate, immediately followed by the formation of magnesite (exotherm) and its decomposition to periclase (last endotherm). Evolution of water and CO2 were consistent with the observed enthalpy changes. A library of such DSC-evolved gas curves for putative Martian minerals are currently being acquired in order to facilitate the interpretation of results obtained by a robotic lander.

  12. Factors influencing the crystallisation of highly concentrated water-in-oil emulsions: A DSC study

    OpenAIRE

    Irina Masalova; Karina Kovalchuk

    2012-01-01

    Highly concentrated emulsions are used in a variety of applications, including the cosmetics, food and liquid explosives industries. The stability of these highly concentrated water-in-oil emulsions was studied by differential scanning calorimetry. Crystallisation of the emulsions was initiated by exposing the emulsions to a low temperature. The effects of surfactant type, electrolyte concentration and electrolyte composition in the aqueous phase on emulsion crystallisation temperature were s...

  13. Optimization of Crystals for Applications in Dual-readout Calorimetry

    International Nuclear Information System (INIS)

    Dual-Readout Calorimetry is a promising new technique for high resolution hadron and jet calorimetry. It is based on simultaneous measurements of the scintillation and Cherenkov light generated in the shower development process. Due to the fact that the Cherenkov light is only produced by the electromagnetic shower component, the relative contribution of this component to the signals can be measured on the event by event basis, resulting in reduction of fluctuations. This leads to an important improvement in the hadronic calorimeter performance. Further improvement on both the electromagnetic and hadronic resolution can be achieved by using homogeneous, dense crystals. This reduces both the sampling fluctuations and the quantum fluctuations. We present a systematic study of lead tungstate crystals doped with a small fraction of molybdenum, varying between 0.1% and 5% and exploring different readout configurations.

  14. Monitoring assembly of ribonucleoprotein complexes by isothermal titration calorimetry

    OpenAIRE

    Recht, Michael I.; Ryder, Sean P.; Williamson, James R.

    2008-01-01

    Isothermal titration calorimetry (ITC) is a useful technique to study RNA-protein interactions, as it provides the only method by which the thermodynamic parameters of free energy, enthalpy, and entropy can be directly determined. This chapter presents a general procedure for studying RNA-protein interactions using ITC, and gives specific examples for monitoring the binding of Caenorhabditis elegans GLD-1 STAR domain to TGE RNA and the binding of Aquifex aeolicus S6:S18 ribosomal protein hete...

  15. Thermal Polymerization of Acrylamide by Differential Scanning Calorimetry

    OpenAIRE

    Kishore, K.; Santhanalakshmi, KN

    1981-01-01

    Thermal polymerization of acrylamide was studied by differential scanning calorimetry. Latent heat of fusion \\bigtriangleup Hf and enthalpy of polymerization \\bigtriangleup Hp values were found to be 36 and $-18.0 kcal mol^{-1}$, respectively. The overall activation energy E for the polymerization was calculated to be $19 k cal mol^{-1}$ up to 60% conversion. The added free-radical inhibitor (benzoquinone) was found to desensitize the thermal polymerization of acrylamide suggesting the polyme...

  16. Application of kinetic inductance thermometers to x-ray calorimetry

    International Nuclear Information System (INIS)

    A kinetic inductance thermometer is applied to x-ray calorimetry, and its operation over a wide range of frequencies and geometries is discussed. Three amplifier configurations are described, one using a superconducting quantum interference device (SQUID) amplifier, another incorporating an FET amplifier in an amplitude modulated system, and the third, using a tunnel diode frequency modulated oscillator circuit. The predicted performance of each configuration is presented. 13 refs., 6 figs., 1 tab

  17. Depth of calorimetry for SSC [Superconducting Super Collider] experiments

    International Nuclear Information System (INIS)

    The depth of calorimetry required for SSC experiments is investigated using data of hadronic shower development in neutrino detectors and a parameterization of average hadronic shower shapes. The effect of hadronic shower fluctuations is included. A depth of nine to ten proton absorption lengths in iron is found to be sufficient to contain at least 95% of the energy of 95% of 1-TeV jets. 6 refs., 5 figs

  18. Accurate Measurement of Heat Capacity by Differential Scanning Calorimetry

    Science.gov (United States)

    1984-01-01

    Experience with high quality heat capacity measurement by differential scanning calorimetry is summarized and illustrated, pointing out three major causes of error: (1) incompatible thermal histories of the sample, reference and blank runs; (2) unstable initial and final isotherms; (3) incompatible differences between initial and final isotherm amplitudes for sample, reference and blank runs. Considering these problems, it is shown for the case of polyoxymethylene that accuracies in heat capacity of 0.1 percent may be possible.

  19. The upgraded CDF front end electronics for calorimetry

    International Nuclear Information System (INIS)

    The front end electronics used in the calorimetry of the CDF detector has been upgraded to meet system requirements for higher expected luminosity. A fast digitizer utilizing a 2 μSec, 16 bit ADC has been designed and built. Improvements to the front end trigger circuitry have been implemented, including the production of 900 new front end modules. Operational experience with the previous system is presented, with discussion of the problems and performance goals

  20. Direct Animal Calorimetry, the Underused Gold Standard for Quantifying the Fire of Life*

    OpenAIRE

    Kaiyala, Karl J.; Ramsay, Douglas S.

    2010-01-01

    Direct animal calorimetry, the gold standard method for quantifying animal heat production (HP), has been largely supplanted by respirometric indirect calorimetry owing to the relative ease and ready commercial availability of the latter technique. Direct calorimetry, however, can accurately quantify HP and thus metabolic rate (MR) in both metabolically normal and abnormal states, whereas respirometric indirect calorimetry relies on important assumptions that apparently have never been tested...

  1. Characteristics of rose hip (Rosa canina L.) cold-pressed oil and its oxidative stability studied by the differential scanning calorimetry method.

    Science.gov (United States)

    Grajzer, Magdalena; Prescha, Anna; Korzonek, Katarzyna; Wojakowska, Anna; Dziadas, Mariusz; Kulma, Anna; Grajeta, Halina

    2015-12-01

    Two new commercially available high linolenic oils, pressed at low temperature from rose hip seeds, were characterised for their composition, quality and DPPH radical scavenging activity. The oxidative stability of oils was assessed using differential scanning calorimetry (DSC). Phytosterols, tocopherols and carotenoids contents were up to 6485.4; 1124.7; and 107.7 mg/kg, respectively. Phenolic compounds determined for the first time in rose hip oil totalled up to 783.55 μg/kg, with a predominant presence of p-coumaric acid methyl ester. Antiradical activity of the oils reached up to 3.00 mM/kg TEAC. The acid, peroxide and p-anisidine values as well as iron and copper contents indicated good quality of the oils. Relatively high protection against oxidative stress in the oils seemed to be a result of their high antioxidant capacity and the level of unsaturation of fatty acids. PMID:26041218

  2. Crystallization and melting behavior of iPP studied by DSC

    OpenAIRE

    Janevski, Aco; Bogoeva-Gaceva, Gordana; GROZDANOV, Anita

    1998-01-01

    This article is a part of a study of model and bulk composites, based on isotactic polypropylene (i-PP) and glass (or carbon) fibers, produced from knitted textile preforms of hybrid yarns. First, we report the results on crystallization and fusion of textile-grade i-PP, used for the processing of hybrid yarns and the corresponding knitted fabrics. The kinetics of the crystallization process, in the dynamic and isothermal regime, was followed by DSC, and the results were analyzed by Avrami, O...

  3. The Impact of Structural Recovery on Dyanamic DSC Measurements: Tool- Narayanaswamy Model Calculations for Typical Polymers

    Science.gov (United States)

    Simon, Sindee L.; McKenna, Gregory B.

    1997-03-01

    It is well known that structural recovery in polymeric glasses leads to highly nonlinear events, such as the enthalpy overshoot, in non-isothermal experiments. One common model for describing these events is the Tool-Narayanaswamy (TN) equation. Here we apply the TN equation to analyze typical modulated DSC experiments and examine the influence of the material nonlinearities on the dynamic heat flow. We also study the effects of nonlinearity on the reversing and non-reversing heat flows and compare the values of Cp obtained from the TN model with those expected from the MDSC when the material nonlinearities are ignored.

  4. DSC study on temperature memory effect of NiTi shape memory alloy

    Institute of Scientific and Technical Information of China (English)

    N. LIU; W. M. HUANG

    2006-01-01

    A systematic study on the temperature memory effect (TME) in a polycrystalline NiTi shape memory alloy was presented. The investigation was carried out through a series of differential scanning calorimeter (DSC) tests. Two types of tests were conducted,namely single-step test and multi-step test. The influence of the step temperature on the peak/trough temperatures in the subsequent heating process and the associated energy absorption/release in the phase transformations was investigated. Using a simple theoretical model,the exact mechanism behind TME was studied.

  5. XRD and TG-DSC analysis of the silicon carbide-palladium reaction

    OpenAIRE

    2014-01-01

    The attack of palladium on silicon carbide was investigated using high purity powders of α-SiC and palladium blended to produce a mixture with composition of 95 at.% SiC and 5 at.% Pd and cold pressed to pellets. The palladium silicon carbide reaction was studied by thermogravimetry (TG) and differential scanning calorimentry (DSC), whereas the phase composition of the specimens was studied using X-ray diffractometry (XRD) before and after thermoscans. X-ray powder analysis (XRD) was employed...

  6. STUDY ON THE SHOCK WAVE CRYSTALLIZATION OF AMORPHOUS ALLOYS BY DSC

    Institute of Scientific and Technical Information of China (English)

    H.Y. Zhao; H. Wang; Q.J. Liu; J.D. Kan; Z.Q. Liu

    2002-01-01

    Shock wave and annealing crystallization of amorphous alloys FeSiB, FeMoSiB andFeCuNbSiB were studied by isothermal and non-isothermal DSC technique. It wasfound that the shock wave crystallization is very perfect, the fraction crystallized isvery close to 100%, though the period of crystallization is very short, only about10-4-10-6 s. Their produced phases differ from the parent phase in structure andcomposition. The high velocity of the transformation is very difficult to explain by thediffusion theory of solid state phase transition.

  7. DSC method: Determination of amorphous fraction in solid dosage and fragility

    Science.gov (United States)

    Saini, Manoj K.

    2015-06-01

    We have used Differential Scanning Calorimeter (DSC) method to quantifying the amorphous content in solid dosage of a commonly used drugs namely mephenesin. The glass transition temperature (Tg) of supercooled liquid sample and melting temperature (Tm) of as received sample are found to be 232.2 K and 343.1 K respectively. The "fragility index" of mephenesin has been discussed in detail using the coupling model (m = 250(± 30) - 320βKWW) and compared with acetaminophen and methocarbamol. The sample studied here is found to be kinetically strong in comparison.

  8. Crystallization and glass transition of the diols and aminoalcohols, according to DSC data

    Science.gov (United States)

    Solonina, I. A.; Rodnikova, M. N.; Kiselev, M. P.; Khoroshilov, A. V.

    2015-05-01

    Overcooling, crystallization, and glass transition of the diol series and aminoalcohols which are the liquids with spatial hydrogen-bond networks, which are the along with the overcooling of dioxane, dimethylsulfoxide, and acetonitrile, which do not have such networks were studied by DSC. The observed phenomena are explained by the stability of H-bond networks. It was concluded that changes in the stability of the networks in and between series of diols and aminoalcohols are due to differences between their molecular structures, the energies of their hydrogen bonds, and their network topologies.

  9. DTA and DSC study on the effect of mechanical dispersion on poly(tetrafluorethylene properties

    Directory of Open Access Journals (Sweden)

    Dumitraşa Mihai

    2014-12-01

    Full Text Available Poly(tetrafluorethylene particles were obtained by mechanical processing of the formed polymer (Teflon bar. In order to assess the effect of mechanical wear on polymer properties, their melting and crystallization behaviour was investigated by DSC and DTA, and the results were compared to the ones obtained for the native polymer. An increase of the crystallinity degree and an accentuated decrease of the average molecular weight were found for the samples submitted to mechanical wear, as a result of mechanical degradation of the polymer

  10. Use of thermal analysis techniques (TG–DSC) for the characterization of diverse organic municipal waste streams to predict biological stability prior to land application

    International Nuclear Information System (INIS)

    Highlights: ► Thermal analysis was used to assess stability and composition of organic matter in three diverse municipal waste streams. ► Results were compared with C mineralization during 90-day incubation, FTIR and 13C NMR. ► Thermal analysis reflected the differences between the organic wastes before and after the incubation. ► The calculated energy density showed a strong correlation with cumulative respiration. ► Conventional and thermal methods provide complimentary means of characterizing organic wastes. - Abstract: The use of organic municipal wastes as soil amendments is an increasing practice that can divert significant amounts of waste from landfill, and provides a potential source of nutrients and organic matter to ameliorate degraded soils. Due to the high heterogeneity of organic municipal waste streams, it is difficult to rapidly and cost-effectively establish their suitability as soil amendments using a single method. Thermal analysis has been proposed as an evolving technique to assess the stability and composition of the organic matter present in these wastes. In this study, three different organic municipal waste streams (i.e., a municipal waste compost (MC), a composted sewage sludge (CS) and a thermally dried sewage sludge (TS)) were characterized using conventional and thermal methods. The conventional methods used to test organic matter stability included laboratory incubation with measurement of respired C, and spectroscopic methods to characterize chemical composition. Carbon mineralization was measured during a 90-day incubation, and samples before and after incubation were analyzed by chemical (elemental analysis) and spectroscopic (infrared and nuclear magnetic resonance) methods. Results were compared with those obtained by thermogravimetry (TG) and differential scanning calorimetry (DSC) techniques. Total amounts of CO2 respired indicated that the organic matter in the TS was the least stable, while that in the CS was the

  11. Thermochemistry of some binary lead and transition metal compounds by high temperature direct synthesis calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Meschel, S.V., E-mail: meschel@jfi.uchicago.edu [Illinois Institute of Technology,Thermal Processing Technology Center, 10 W. 32nd Street, Chicago, Illinois 60615 (United States); Gordon Center for Integrated Science, 929 E. 57th Street, Chicago, Illinois 60637 (United States); Nash, P. [Illinois Institute of Technology,Thermal Processing Technology Center, 10 W. 32nd Street, Chicago, Illinois 60615 (United States); Chen, X.Q.; Wei, P. [Materials processing Modeling Division, Shenyang National Laboratory for Materials Science, Institute of Metals Research, 72 Wenhua Road, Shenyang City (China)

    2015-06-05

    Highlights: • Studied binary lead-transition metal alloys by high temperature calorimetry. • Determined the enthalpies of formation of 8 alloys. • Compared the measurements with predictions by the model of Miedema and by the ab initio method. - Abstract: The standard enthalpies of formation of some binary lead and transition metal compounds have been measured by high temperature direct synthesis calorimetry. The reported results are: Pb{sub 3}Sc{sub 5}(−61.3 ± 2.9); PbTi{sub 4}(−16.6 ± 2.4); Pb{sub 3}Y{sub 5}(−64.8 ± 3.6); Pb{sub 3}Zr{sub 5}(−50.6 ± 3.1); PbNb{sub 3}(−10.4 ± 3.4); PbRh(−16.5 ± 3.3); PbPd{sub 3}(−29.6 ± 3.1); PbPt(−34.7 ± 3.3) kJ/mole of atoms. We will compare our results with previously published measurements. We will also compare the experimental measurements with enthalpies of formation of transition metal compounds with elements in the same vertical column in the periodic table. We will compare our measurements with predicted values on the basis of the semi empirical model of Miedema and coworkers and with ab initio values when available.

  12. A High-Throughput Biological Calorimetry Core: Steps to Startup, Run, and Maintain a Multiuser Facility.

    Science.gov (United States)

    Yennawar, Neela H; Fecko, Julia A; Showalter, Scott A; Bevilacqua, Philip C

    2016-01-01

    Many labs have conventional calorimeters where denaturation and binding experiments are setup and run one at a time. While these systems are highly informative to biopolymer folding and ligand interaction, they require considerable manual intervention for cleaning and setup. As such, the throughput for such setups is limited typically to a few runs a day. With a large number of experimental parameters to explore including different buffers, macromolecule concentrations, temperatures, ligands, mutants, controls, replicates, and instrument tests, the need for high-throughput automated calorimeters is on the rise. Lower sample volume requirements and reduced user intervention time compared to the manual instruments have improved turnover of calorimetry experiments in a high-throughput format where 25 or more runs can be conducted per day. The cost and efforts to maintain high-throughput equipment typically demands that these instruments be housed in a multiuser core facility. We describe here the steps taken to successfully start and run an automated biological calorimetry facility at Pennsylvania State University. Scientists from various departments at Penn State including Chemistry, Biochemistry and Molecular Biology, Bioengineering, Biology, Food Science, and Chemical Engineering are benefiting from this core facility. Samples studied include proteins, nucleic acids, sugars, lipids, synthetic polymers, small molecules, natural products, and virus capsids. This facility has led to higher throughput of data, which has been leveraged into grant support, attracting new faculty hire and has led to some exciting publications. PMID:26794364

  13. Thermochemistry of some binary lead and transition metal compounds by high temperature direct synthesis calorimetry

    International Nuclear Information System (INIS)

    Highlights: • Studied binary lead-transition metal alloys by high temperature calorimetry. • Determined the enthalpies of formation of 8 alloys. • Compared the measurements with predictions by the model of Miedema and by the ab initio method. - Abstract: The standard enthalpies of formation of some binary lead and transition metal compounds have been measured by high temperature direct synthesis calorimetry. The reported results are: Pb3Sc5(−61.3 ± 2.9); PbTi4(−16.6 ± 2.4); Pb3Y5(−64.8 ± 3.6); Pb3Zr5(−50.6 ± 3.1); PbNb3(−10.4 ± 3.4); PbRh(−16.5 ± 3.3); PbPd3(−29.6 ± 3.1); PbPt(−34.7 ± 3.3) kJ/mole of atoms. We will compare our results with previously published measurements. We will also compare the experimental measurements with enthalpies of formation of transition metal compounds with elements in the same vertical column in the periodic table. We will compare our measurements with predicted values on the basis of the semi empirical model of Miedema and coworkers and with ab initio values when available

  14. Estimation of the nucleation rate by differential scanning calorimetry

    Science.gov (United States)

    Kelton, Kenneth F.

    1992-01-01

    A realistic computer model is presented for calculating the time-dependent volume fraction transformed during the devitrification of glasses, assuming the classical theory of nucleation and continuous growth. Time- and cluster-dependent nucleation rates are calculated by modeling directly the evolving cluster distribution. Statistical overlap in the volume fraction transformed is taken into account using the standard Johnson-Mehl-Avrami formalism. Devitrification behavior under isothermal and nonisothermal conditions is described. The model is used to demonstrate that the recent suggestion by Ray and Day (1990) that nonisothermal DSC studies can be used to determine the temperature for the peak nucleation rate, is qualitatively correct for lithium disilicate, the glass investigated.

  15. Application of the modulated temperature differential scanning calorimetry technique for the determination of the specific heat of copper nanofluids

    International Nuclear Information System (INIS)

    The purpose of this work is to investigate the applicability of the modulated temperature differential scanning calorimetry technique to measure specific heat of copper nanofluids by using the ASTM E2719 standard procedure, which is generally applied to thermally stable solids and liquids. The one-step method of preparation of copper nanofluid samples is described. The synthesized nanoparticles were separated from the base fluid and examined by X-ray diffraction and transmission electron microscopy in order to evaluate their structure, morphology and chemical nature. The presence of copper nanoparticles in the base fluid alters the characteristics of crystallization and melting processes and reduces the specific heat values of nanofluids in the whole studied temperature range. - Highlights: ► Copper nanofluids prepared by one-step method. ► Methodology of synthesis improved nanofluid stability. ► Specific heat determinations using modulated temperature differential scanning calorimetry. ► Good agreement between theoretical and experimental values.

  16. Kinetics of solid-gas reactions characterized by scanning AC nano-calorimetry with application to Zr oxidation

    International Nuclear Information System (INIS)

    Scanning AC nano-calorimetry is a recently developed experimental technique capable of measuring the heat capacity of thin-film samples of a material over a wide range of temperatures and heating rates. Here, we describe how this technique can be used to study solid-gas phase reactions by measuring the change in heat capacity of a sample during reaction. We apply this approach to evaluate the oxidation kinetics of thin-film samples of zirconium in air. The results confirm parabolic oxidation kinetics with an activation energy of 0.59 ± 0.03 eV. The nano-calorimetry measurements were performed using a device that contains an array of micromachined nano-calorimeter sensors in an architecture designed for combinatorial studies. We demonstrate that the oxidation kinetics can be quantified using a single sample, thus enabling high-throughput mapping of the composition-dependence of the reaction rate.

  17. Energy dispersive x-ray diffractometry as a tool alternative to differential scanning calorimetry for investigating polymer phase transitions

    International Nuclear Information System (INIS)

    Recently, a technique based on energy dispersive x-ray diffraction has been proposed to follow the polymer phase transitions. However, the potentialities of this method were not clear, as well as the experimental conditions in which it is more convenient than differential scanning calorimetry, generally used for the same purpose. In the present letter, the answer to this question is provided. It is shown that the two methods are complementary, rather than equivalent, the heating rate being the relevant parameter to establish which is preferable. The demonstration of this statement is given through the observation of the complex thermal properties of a reference sample studied in both ways at progressively lower heating rates. The connection between such unusual application of x-ray diffraction and the differential scanning calorimetry is discussed in terms of the two possible definitions of entropy

  18. DMSO-Induced Dehydration of DPPC Membranes Studied by X-ray Diffraction, Small-Angle Neutron Scattering, and Calorimetry

    CERN Document Server

    Kiselev, M A; Kisselev, A M; Grabielle-Madelmond, C; Ollivon, M

    1999-01-01

    The influence of dimethyl sulfoxide (DMSO) on membrane thickness, multilamellar repeat distance, and phase transitions of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) was investigated by X-ray diffraction and small-angle neutron scattering (SANS). The differential scanning calorimetry (DSC) study of water freezing and ice melting was performed in the ternary DPPC /DMSO /water and binary DMSO /water systems. The methods applied demonstrated the differences in membrane structure in three sub-regions of the DMSO mole fraction (X_dmso): from 0.0 to 0.3 for the first, from 0.3 to 0.8 for the second, and from 0.9 to 1.0 for the third sub-region. The thickness of the intermembrane solvent at T =20C decreases from 14.4 +/- 1.8 A at X_dmso =0.0 to 7.8 +/- 1.8 A at X_dmso =0.1. The data were used to determine the number of free water molecules in the intermembrane space in the presence of DMSO. The results for 0.0 < X_dmso < 0.3 were explained in the framework of DMSO-induced dehydration of the interme...

  19. Weak interactions in clobazam–lactose mixtures examined by differential scanning calorimetry: Comparison with the captopril–lactose system

    International Nuclear Information System (INIS)

    Highlights: ► Thermodynamic and kinetic parameters of weak interactions in binary systems by DSC. ► Energy-barrier decrease for lactose dehydration induced by clobazam. ► Recrystallisation of metastable liquid clobazam induced by anhydrous alpha lactose. ► Decrease of lactose dehydration temperature in binary mixtures with captopril. ► Increase of lactose dehydration enthalpy in binary mixtures with captopril. - Abstract: The thermal behaviour of binary mixtures of two drugs (clobazam and captopril, respectively) and a pharmaceutical excipient (lactose monohydrate) was measured with differential scanning calorimetry to determine thermodynamic and kinetic parameters (dehydration and melting enthalpies and dehydration and glass-transition activation energies) which might be affected by intermolecular interactions. A kinetic study showed that lactose dehydration is not a single-step conversion and that clobazam contributed to reduce the energy barrier for the bulk dehydration of the excipient. On the other hand, the physical interactions between metastable liquid clobazam and crystalline anhydrous α-lactose obtained from monohydrate dehydration gave rise to the recrystallisation of clobazam. In the captopril–lactose system, the liquid captopril influenced the lactose dehydration: a sharp increase of the dehydration enthalpy and a concurrent reduction of the dehydration temperature were observed. Finally, it turned out that solid-phase transitions were enhanced by the contact with a liquid phase.

  20. Weak interactions in clobazam-lactose mixtures examined by differential scanning calorimetry: Comparison with the captopril-lactose system

    Energy Technology Data Exchange (ETDEWEB)

    Toscani, S. [Departement de Chimie - UMR 6226, Faculte des Sciences, Universite de Rennes 1, Batiment 10B, 263 avenue du General Leclerc, F-35042 Rennes Cedex (France); Cornevin, L. [Universite de Rennes 1, Faculte de Pharmacie, 2 Avenue Leon Bernard, F-35043 Rennes Cedex (France); Burgot, G., E-mail: Gwenola.burgot@univ-rennes1.fr [Universite de Rennes 1, Faculte de Pharmacie, Laboratoire de Chimie Analytique, EA 1274 ' Mouvement, sports, sante' , 2 Avenue Leon Bernard, F-35043 Rennes Cedex (France); CHGR Rennes, Pole Medico-Technique Pharmacie, F-35703 Rennes Cedex (France)

    2012-09-10

    Highlights: Black-Right-Pointing-Pointer Thermodynamic and kinetic parameters of weak interactions in binary systems by DSC. Black-Right-Pointing-Pointer Energy-barrier decrease for lactose dehydration induced by clobazam. Black-Right-Pointing-Pointer Recrystallisation of metastable liquid clobazam induced by anhydrous alpha lactose. Black-Right-Pointing-Pointer Decrease of lactose dehydration temperature in binary mixtures with captopril. Black-Right-Pointing-Pointer Increase of lactose dehydration enthalpy in binary mixtures with captopril. - Abstract: The thermal behaviour of binary mixtures of two drugs (clobazam and captopril, respectively) and a pharmaceutical excipient (lactose monohydrate) was measured with differential scanning calorimetry to determine thermodynamic and kinetic parameters (dehydration and melting enthalpies and dehydration and glass-transition activation energies) which might be affected by intermolecular interactions. A kinetic study showed that lactose dehydration is not a single-step conversion and that clobazam contributed to reduce the energy barrier for the bulk dehydration of the excipient. On the other hand, the physical interactions between metastable liquid clobazam and crystalline anhydrous {alpha}-lactose obtained from monohydrate dehydration gave rise to the recrystallisation of clobazam. In the captopril-lactose system, the liquid captopril influenced the lactose dehydration: a sharp increase of the dehydration enthalpy and a concurrent reduction of the dehydration temperature were observed. Finally, it turned out that solid-phase transitions were enhanced by the contact with a liquid phase.

  1. Effect of polyglycerol esters additive on palm oil crystallization using focused beam reflectance measurement and differential scanning calorimetry.

    Science.gov (United States)

    Saw, M H; Hishamuddin, E; Chong, C L; Yeoh, C B; Lim, W H

    2017-01-01

    The effect of 0.1-0.7% (w/w) of polyglycerol esters (PGEmix-8) on palm oil crystallization was studied using focused beam reflectance measurement (FBRM) to analyze the in-line changes of crystal size distribution during the crystallization. FBRM results show that 0.1-0.5% (w/w) of PGEmix-8 did not significantly affect nucleation but slightly retarded crystal growth. The use of 0.7% (w/w) additive showed greater heterogeneous nucleation compared to those with lower dosages of additive. Crystal growth was also greatly reduced when using 0.7% (w/w) dosage. The morphological study indicated that the palm oil crystals were smaller and more even in size than when more additive was added. Isothermal crystallization studies using differential scanning calorimetry (DSC) showed increased inhibitory effects on palm oil crystal growth with increasing concentration of PGEmix-8. These results imply that PGEmix-8 is a nucleation enhancing and crystal growth retarding additive in palm oil crystallization at 0.7% (w/w) dosage. PMID:27507476

  2. Differential scanning calorimetry studies of Se85Te15-xPbx (x 4,6,8 and 10) glasses

    International Nuclear Information System (INIS)

    Results of differential scanning calorimetry (DSC) studies of Se85Te15-xPbx (x = 4, 6, 8 and 10) glasses have been reported and discussed in this paper. The results have been analyzed on the basis of structural relaxation equation, Matusita's equation and modified Kissinger's equation. The activation energies of structural relaxation lie in between 226 and 593 kJ/mol. The crystallization growth is found to be one-dimensional for all compositions. The activation energies of crystallization are found to be 100-136 kJ/mol by Matusita's equation while 102-139 kJ/mol by modified Kissinger's equation. The Hruby number (indicator of ease of glass forming and higher stability) is the highest for Se85Te9Pb6 glass while S factor (indicator of resistance to devitrification) is highest for Se85Te7Pb8 glass at all heating rates in our experiment. Further the highest resistance to devitrification has the highest value of structural activation energy and the activation energy of crystallization is maximum for the most stable glass by both Matusita's equation and the modified Kissinger's equation. (author)

  3. Differential scanning calorimetry studies of Se85Te15–Pb ( = 4, 6, 8 and 10) glasses

    Indian Academy of Sciences (India)

    N B Maharajan; N S Saxena; Deepika Bhandari; Mousa M Imran; D D Paudyal

    2000-10-01

    Results of differential scanning calorimetry (DSC) studies of Se85Te15–Pb ( = 4, 6, 8 and 10) glasses have been reported and discussed in this paper. The results have been analyzed on the basis of structural relaxation equation, Matusita’s equation and modified Kissinger’s equation. The activation energies of structural relaxation lie in between 226 and 593 kJ/mol. The crystallization growth is found to be onedimensional for all compositions. The activation energies of crystallization are found to be 100–136 kJ/mol by Matusita’s equation while 102–139 kJ/mol by modified Kissinger’s equation. The Hruby number (indicator of ease of glass forming and higher stability) is the highest for Se85Te9Pb6 glass while S factor (indicator of resistance to devitrification) is highest for Se85Te7Pb8 glass at all heating rates in our experiment. Further the highest resistance to devitrification has the highest value of structural activation energy and the activation energy of crystallization is maximum for the most stable glass by both Matusita’s equation and the modified Kissinger’s equation.

  4. Activation Enthalpies of Deformation-Induced Lattice Defects in Severe Plastic Deformation Nanometals Measured by Differential Scanning Calorimetry

    Science.gov (United States)

    Setman, Daria; Kerber, Michael B.; Schafler, Erhard; Zehetbauer, Michael J.

    2010-04-01

    Samples of 99.99 pct pure copper and nickel of 99.998 pct purity were deformed by high-pressure torsion (HPT) at different hydrostatic pressures, to different shear strains. Activation enthalpies ( Q) were determined by differential scanning calorimetry (DSC) using Kissinger’s method. For the one annealing peak found in HPT Cu, Q amounts to Q = 0.78 to 0.48 eV depending on the shear strain applied. In the case of Ni, the activation enthalpies of the two annealing peaks were determined as Q = 0.65 eV and Q = 0.95 eV, respectively, with no obvious dependence on shear strain, although this has been indicated by the annealing peak temperatures. Applying defect specific analyses of the annealing peaks, it turned out that the larger Q value represents the annihilation of dislocations and agglomerates, while the smaller one reflects the annihilation of single or double vacancies. Concerning the strain dependence of the larger Q, two possible explanations have been discussed: (1) the annihilation of dislocations assisted by the strain-dependent density of vacancy agglomerates and (2) the annihilation of dislocations enhanced by a strain-dependent level of long-range internal stresses. Because of closer correlations of Q with external and internal stresses at very high shear strains, explanation (2) has been favored.

  5. On the Interpretation of Low Temperature Calorimetry Data

    DEFF Research Database (Denmark)

    Kjeldsen, Ane Mette; Geiker, Mette Rica

    2008-01-01

    The effect of selected factors and phenomena on Low Temperature Calorimetry (LTC) results has been investigated, in order to determine the possibilities and limitations of using LTC for characterisation of the porosity of cement-based materials. LTC was carried out on a model material with mono...... ions on freezing point depression into account. It is proposed that the connectivity of pores, e.g. in cement-based materials, may be characterised based on cooling curves, whereas the pore size distribution may be characterised based on the heating curve. Cooling should be undertaken at a high rate to...

  6. Fabrication of 12% {sup 240}Pu calorimetry standards

    Energy Technology Data Exchange (ETDEWEB)

    Long, S.M.; Hildner, S.; Gutierrez, D.; Mills, C.; Garcia, W.; Gurule, C.

    1995-08-01

    Throughout the DOE complex, laboratories are performing calorimetric assays on items containing high burnup plutonium. These materials contain higher isotopic range and higher wattages than materials previously encountered in vault holdings. Currently, measurement control standards have been limited to utilizing 6% {sup 240}Pu standards. The lower isotopic and wattage value standards do not complement the measurement of the higher burnup material. Participants of the Calorimetry Exchange (CALEX) Program have identified the need for new calorimetric assay standards with a higher wattage and isotopic range. This paper describes the fabrication and verification measurements of the new CALEX standard containing 12% {sup 240}Pu oxide with a wattage of about 6 to 8 watts.

  7. Fast, radiation-hard charge preamplifier for warm liquid calorimetry

    International Nuclear Information System (INIS)

    The authors describe the design, construction, and operation of an ultra-sensitive, high-bandwidth charge preamplifier for calorimetry at the Superconducting Super Collider. The design is based on a monolithic, bipolar technology with 5 Mrad radiation hardness. The intrinsic low noise (≤ 600 e- rms) and low power consumption (60 mwatt) of this device at room temperature make it an attractive front-end preamp for either warm or cryogenic liquid media detectors, or even for tetrodes for scintillating fiber technology. Measurements are reported on a prototype device built in an industrial BiFET process with a 37 nsec risetime

  8. Application of pressure perturbation calorimetry to lipid bilayers.

    OpenAIRE

    Heerklotz, Heiko; Seelig, Joachim

    2002-01-01

    Pressure perturbation calorimetry (PPC) is a new method that measures the heat consumed or released by a sample after a sudden pressure jump. The heat change can be used to derive the thermal volume expansion coefficient, alpha(V), as a function of temperature and, in the case of phase transitions, the volume change, DeltaV, occurring at the phase transition. Here we present the first report on the application of PPC to determine these quantities for lipid bilayers. We measure the volume chan...

  9. A custom floating point format ADC for LHC calorimetry

    International Nuclear Information System (INIS)

    Due to their large dynamic range (in excess of 16 bits) signals from LHC calorimetry poses severe problems to the shaping and digitizing circuits. We are investigating a solution for an ADC based on a custom floating point format. Since the calorimeter precision is limited, the full dynamic range can be split into 8 positive sub-ranges and 5 negative ones, each with an 8 bits dynamic. The reduced number of bits (8 for the mantissa, 4 for the exponent and 1 for the sign) translates itself into a reduction of the power consumption both of the ADC and of the following digital filtering stages. (authors)

  10. Study of Polymer Glasses by Modulated Differential Scanning Calorimetry in the Undergraduate Physical Chemistry Laboratory

    Science.gov (United States)

    Folmer, J. C. W.; Franzen, Stefan

    2003-07-01

    Recent technological advances in thermal analysis present educational opportunities. In particular, modulated differential scanning calorimetry (MDSC) can be used to contrast reversing and nonreversing processes in practical laboratory experiments. The introduction of these concepts elucidates the relationship between experimental timescales and reversibility. The latter is a key concept of undergraduate thermodynamics theory that deserves reinforcement. In this paper, the theory and application of MDSC to problems of current interest is outlined with special emphasis on the contrast between crystallization and vitrification. Glass formation deserves greater emphasis in the undergraduate curriculum. Glass transitions are increasingly recognized as an important aspect of materials properties and dynamics in fields ranging from polymer science to protein folding. The example chosen for study is a comparison of polyethylene glycol and atactic polypropylene glycol. The experiment is easily performed in a typical three-hour lab session.

  11. Energetics of methanol and formic acid oxidation on Pt(111): Mechanistic insights from adsorption calorimetry

    Science.gov (United States)

    Silbaugh, Trent L.; Karp, Eric M.; Campbell, Charles T.

    2016-08-01

    The catalytic and electrocatalytic oxidation and reforming of methanol and formic acid have received intense interest due to potential use in direct fuel cells and as prototype models for understanding electrocatalysis. Consequently, the reaction energy diagram (energies of all the adsorbed intermediates and activation energies of all the elementary steps) have been estimated for these reactions on Pt(111) by density functional theory (DFT) in several studies. However, no experimental measurement of these energy diagrams have been reported, nor is there a consensus on the mechanisms. Here, we use energies of key intermediates on Pt(111) from single crystal adsorption calorimetry (SCAC) and temperature programmed desorption (TPD) to build a combined energy diagram for these reactions. It suggests a new pathway involving monodentate formate as a key intermediate, with bidentate formate only being a spectator species that slows the rate. This helps reconcile conflicting proposed mechanisms.

  12. Evaluation of aluminosilicate glass sintering during differential scanning calorimetry

    International Nuclear Information System (INIS)

    In this work a difference in the baseline in differential scanning calorimetry analyses, observed in a work where aluminosilicate glasses microspheres containing Ho were studied for application in selective internal radiotherapy as hepatocellular carcinoma treatment, was studied. The glasses with nominal composition 53,7 SiO2 .10,5 Al2O3 . 35,8 MgO in %mol were produced from traditional melting. The first obtained were milled and sieved in the range of 45 a 63 μm. The material was used to produce glass microspheres by the gravitational fall method. The glass powder and the microspheres were characterized by X ray fluorescence spectrometry, laser diffraction, X ray diffraction, differential scanning calorimetry, differential thermal analysis, thermogravimetry, mass spectrometry, and scanning electron microscopy. After the thermal analyses, pellets were formed in the crucibles and were analyzed by scanning electron microscopy, X ray diffraction, and He pycnometry. The difference in the baseline was associated to the viscous flow sintering process and happens because of the decrease in the detected heat flow due to the sample shrinkage. Other events as concurrent crystallization with the sintering process were also studied. (author)

  13. Temperature Modulated DSC and Stiffness Threshold in Ge_xSe_1-x Glasses

    Science.gov (United States)

    Bresser, W. J.; Feng, Xingwei; Boolchand, P.; Schilthuis, J.

    1997-03-01

    We have examined binary Ge_xSe_1-x glasses over a wide composition range 0 MDSC. The glass transitions deduced from the heat flow increase monotonically with x or = 2(1+x), the average coordination number. The heat flow near Tg shows a rather striking threshold behavior (minimum) near x = 0.23, corresponding to the composition at which the glass network begins to abruptly stiffen as noted by an upshift in Raman mode frequencies(Xingwei Feng, et al., to be published.). The present observations suggest that the minimum in Cp change at Tg near the stiffness threshold, deduced from ordinary DSC(M. Tatsumisago, B.L. Halfpap, J.L. Green, S.M. Lindsay, and C.A. Angell, Phys. Rev. Lett. 64, 1549 (1990).), i.e., total heat flow, largely derives from the non-reversing component (relaxation related) heat flow near T_g.

  14. Complex Heat Capacity of Lithium Borate Glasses Studied by Modulated DSC

    International Nuclear Information System (INIS)

    Complex heat capacity, Cp* = Cp' - iCp'', of lithium borate glasses Li2O·(1-x)B2O3 (x = 0.00 - 0.33) has been investigated by Modulated DSC (MDSC). We have successfully observed the frequency dependent Cp* by MDSC in the frequency range 0.01 to 0.1 Hz, and the average relaxation time of glass transition has been determined as a function of temperature. Moreover, the composition dependence of the thermal properties has been investigated. The calorimetric glass transition temperatures become higher with the increase of concentration of Li2O and show the board maximum around x = 0.26-0.28. The width of glass transition region becomes narrower as Li2O increases. These results relate to the change of the fragility of the system. It has been proven that the complex heat capacity spectroscopy by MDSC is a powerful tool to investigate the glass transition phenomena

  15. Complex Heat Capacity of Lithium Borate Glasses Studied by Modulated DSC

    Science.gov (United States)

    Matsuda, Yu; Matsui, Chihiro; Ike, Yuji; Kodama, Masao; Kojima, Seiji

    2006-05-01

    Complex heat capacity, Cp* = Cp' - iCp″, of lithium borate glasses Li2Oṡ(1-x)B2O3 (x = 0.00 - 0.33) has been investigated by Modulated DSC (MDSC). We have successfully observed the frequency dependent Cp* by MDSC in the frequency range 0.01 to 0.1 Hz, and the average relaxation time of glass transition has been determined as a function of temperature. Moreover, the composition dependence of the thermal properties has been investigated. The calorimetric glass transition temperatures become higher with the increase of concentration of Li2O and show the board maximum around x = 0.26-0.28. The width of glass transition region becomes narrower as Li2O increases. These results relate to the change of the fragility of the system. It has been proven that the complex heat capacity spectroscopy by MDSC is a powerful tool to investigate the glass transition phenomena.

  16. Fabrication and laboratory testing of a high-temperature superconducting subsystem for DSC1800 mobile communications

    International Nuclear Information System (INIS)

    In this paper, we report on the design, fabrication and testing of a 20-pole high-temperature superconducting (HTS) filter for DSC1800 mobile communications with the pass band from 1710 to 1785 MHz. The test results show that the insertion loss of the pass band is less than 0.3 dB, the out-of-band rejection is better than 65 dB, and the steepness of the band edges is greater than 14 dB MHz-1. We also tested an HTS subsystem, which consists of the HTS filter, a low-noise amplifier (LNA) with 21 dB gain and a Stirling Cooler, and a traditional subsystem, which consists of a traditional filter and a LNA with 23 dB gain. The results show that the HTS subsystem is much better than the conventional subsystem

  17. DSC and conductivity studies on PVA based proton conducting gel electrolytes

    Indian Academy of Sciences (India)

    S L Agrawal; Arvind Awadhia

    2004-12-01

    An attempt has been made in the present work to prepare polyvinyl alcohol (PVA) based proton conducting gel electrolytes in ammonium thiocyanate (NH4SCN) solution and characterize them. DSC studies affirm the formation of gels along with the presence of partial complexes. The cole–cole plots exhibit maximum ionic conductivity (2.58 × 10-3 S cm-1) for gel samples containing 6 wt% of PVA. The conductivity of gel electrolytes exhibit liquid like nature at low polymer concentrations while the behaviour is seen to be affected by the formation of PVA–NH4SCN complexes upon increase in polymer content beyond 5 wt%. Temperature dependence of ionic conductivity exhibits VTF behaviour.

  18. Estimation of Critical Temperature of Thermal Explosion for Nitrosubstituted Azetidines Using Non-isothermal DSC

    Institute of Scientific and Technical Information of China (English)

    HU, Rongzu; ZHAO, Fengqi; GAO, Hongxu; ZHANG, Jiaoqiang; ZHANG, Hai; MA, Haixia

    2009-01-01

    Based on reasonable hypothesis, two general expressions and their six derived formulae for estimating the critical temperature (T_b) of thermal explosion for energetic materials (EM) were derived from the Semenov's thermal explosion theory and eight non-isothermal kinetic equations. We can easily obtain the values of the initial temperature (T_(0i)) at which DSC curve deviates from the baseline of the non-isothermal DSC curve of EM, the onset temperature (T_(ei)), the exothermic decomposition reaction kinetic parameters and the values of T_(00) and T_(e0) from the equation T_(0i or ei)=T_(00 or e0)+α_1β_i+α_2β_i~2+…+α_(L-2)β_i~(L-2), i=1,2,…,L and then calculate the values of T_b by the six derived formulae. The T_b values for seven nitrosubstituted azetidines, 3,3-dinitroazetidinium nitrate (1), 3,3-dinitroazetidinium picrate (2), 3,3-dinitroazetidinium-3-nitro-1,2,4-triazol-5-onate (3), 1,3-bis(3',3'-dinitro-azetidine group)-2,2-dinitropropane (4), 1-(2',2',2'-trinitroethyi)-3,3-dinitroazetidine (5), 3,3-dinitroazetidinium perchiorate (6) and 1-(3',Y-dinitroazetidineyl)-2,2-dinitropropane (7), obtained with the six derived formulae are agreeable to each other, whose differences are within 1.5%. The results indicate that the heat-resistance stability of the seven nitrosubstituted azetidines decreases in the order 6>7>5>4>3>2>1.

  19. Thermodynamic study of ibuprofen by adiabatic calorimetry and thermal analysis

    International Nuclear Information System (INIS)

    Molar heat capacities of ibuprofen were precisely measured with a small sample precision automated adiabatic calorimeter over the temperature range from 80 to 400 K. The polynomial functions of Cp,m (J K-1 mol-1) versus T were established on the heat capacity measurements by means of the least fitting square method. The functions are as follows: for solid ibuprofen, at the temperature range of 79.105 K≤T≤333.297 K, Cp,m=144.27+77.046X+3.5171X2+10.925X3+11.224X4, where X=(T-206.201)/127.096; for liquid ibuprofen, at the temperature range of 353.406 K≤T≤378.785 K, Cp,m=325.79+8.9696X-1.6073X2-1.5145X3, where X=(T-366.095)/12.690. A fusion transition at T=348.02 K was found from the Cp-T curve. The molar enthalpy and entropy of the fusion transition were determined to be 26.65 kJ mol-1 and 76.58 J mol-1 K-1, respectively. The thermodynamic functions on the base of the reference temperature of 298.15 K, (HT-H298.15) and (ST-S298.15), were derived. Thermal characteristic of ibuprofen was studied by thermo-gravimetric analysis (TG-DTG) and differential scanning calorimeter (DSC). The temperature of fusion, the molar enthalpy and entropy of fusion obtained by DSC were well consistent with those obtained by adiabatic calorimeter. The evaporation process of ibuprofen was investigated further by TG and DTG, and the activation energy of the evaporation process was determined to be 80.3±1.4 kJ mol-1

  20. Comparison study of trapped water in human erythrocytes by EPC and DSC method and its application

    Institute of Scientific and Technical Information of China (English)

    ZHAO; Gang; HE; Liqun; GUO; Xiaojie; LIU; Zhong; LUO; Dawei

    2004-01-01

    The novel differential scanning calorimetry method for determining trapped water volume of human red blood cell during freezing process has been reexamined. Results show that the final erythrocyte volume is 53% of its isotonic volume after freezing to -40℃. An electronic particle counter (MultisizerTM III, Beckman Coulter Inc., USA) was used to measure cell volume changes in response to hypertonic solution. Using this approach, when extracellular solution was 3186 mOsm, the equilibrium cell volume was found to be 57% of its isotonic value. Both results indicate that 34%-40% of intracellular water is trapped and cannot respond to osmotic difference between intra- and extracellular solution. These findings are consistent with the published data: at least 20%-32% of the isotonic cell water volume is retained within RBCs during freezing. Some applications of the values of trapped water are addressed.

  1. DSC study of phase transitions of cephalin pseudo-binary systems in excess water

    Institute of Scientific and Technical Information of China (English)

    王邦宁; 谈夫

    1999-01-01

    The gel-liquid crystal phase transitions of the pseudo-binary systems of cephalins DMPE and DHPE in excess water were studied by differential scanning calorimetry. The phase diagram of the pseudo-binary systems has been given. The experiments showed that the partial phase separation in gel phase might occur at least at the mole fractions of DHPE below 0.1. The analysis by the model of ideal solution showed that both the cephalins were non-ideally miscible both in the gel phases and in the liquid crystal phases. The analysis by the model of regular solution showed that all the non-ideality parameters in the gel phases were larger than those in the liquid crystal phases at the same temperature. All the non-ideality parameters were not constant, but rather dependent on temperature.

  2. Electrical conductivity, differential scanning calorimetry, X-ray diffraction, and 7Li nuclear magnetic resonance studies of n-CxH(2x+1)OSO3Li (x = 12, 14, 16, 18, and 20)

    International Nuclear Information System (INIS)

    Electrical conductivity (σ), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) measurements of n-C xH(2x+1)OSO3Li (x= 12, 14, 16, 18, and 20) crystals were performed as a function of temperature. In addition, σ, DSC, and XRD observations of n-C xH(2x+1)OSO3Na and n-C xH(2x+1)OSO3K (x= 12, 14, 16, 18, and 20) crystals were carried out for comparison. DSC results of the salts revealed several solid-solid phase transitions with large entropy changes (ΔS). For n-C 18H37OSO3Li and n-C 20H41OSO3Li salts, each melting point produced a small ΔSmp value compared with the total entropy change in the solid phases (ΔStr1+ΔStr2). Additionally, Li + ion diffusion was detected in the highest temperature solid phases. For K salts, larger σ values were detected for potassium alkylsulfates compared with those reported for alkyl carboxylate. 7Li NMR spectra of n-C 18H37OSO3Li crystals recorded in the low-temperature phase showed large asymmetry parameters, suggesting the Li + ions are localized at asymmetric sites in the crystals

  3. Application of an open circuit indirect calorimetry system for gaseous exchange measurements in small ruminant nutrition

    OpenAIRE

    CRISCIONI FERREIRA, PATRICIA FABIOLA

    2016-01-01

    [EN] The main objective of this Thesis was to study the energy metabolism in small ruminants under different nutrition sceneries. As methodology we utilized indirect calorimetry instead of direct calorimetry or feeding trials. Within indirect calorimetry we worked with a portable open circuit gas exchange system with a head hood. This open circuit respiration system permitted completed the whole energy balance and evaluate the efficiency of utilization of the energy of the diet for different ...

  4. A scanning AC calorimetry technique for the analysis of nano-scale quantities of materials

    OpenAIRE

    Vlassak, Joost J.; Xiao, Kechao; John M. Gregoire; McCluskey, Patrick J.

    2012-01-01

    We present a scanning AC nanocalorimetry method that enables calorimetry measurements at heating and cooling rates that vary from isothermal to \\(2×10^3 K/s\\), thus bridging the gap between traditional scanning calorimetry of bulk materials and nanocalorimetry. The method relies on a micromachined nanocalorimetry sensor with a serpentine heating element that is sensitive enough to make measurements on thin-film samples and composition libraries. The ability to perform calorimetry over such a ...

  5. Neural second-level trigger system based on calorimetry

    Science.gov (United States)

    Seixas, J. M.; Caloba, L. P.; Souza, M. N.; Braga, A. L.; Rodrigues, A. P.

    1996-06-01

    A second-level triggering system based on calorimetry is analyzed using neural networks. Calorimeter data in a LHC environment is obtained with Monte Carlo simulations and an algorithm for the first-level trigger operation is applied. The surviving events are then available as a 20×20 matrix information corresponding to the calorimeter towers in the region of interest. The dominant background for triggering on electrons is assumed to consist of QCD jets which passed the first-level trigger condition. The main features of the calorimeter are extracted. Matrix information, shower deposition in concentric rings and tail weighting procedures are studied. The processed information is sent to a fully connected backpropagation neural network. In this analysis we also consider pileup effects of an average of 20 minimum bias events. The neural network based system achieved up to 99% electron efficiency with less than 9% of jets being misclassified as electrons. Implementation on digital signal processors is suggested.

  6. Present status of CMS HF quartz fiber calorimetry

    CERN Document Server

    Önel, Y M

    2002-01-01

    The experiments at the Large Hadron Collider will have to deal with unprecedented radiation levels. The design of the CMS forward calorimetry detector (HF) is now finalized. The present design of CMS calls for the HF calorimeter to be based on quartz fiber technology. It consists of two modules, located symmetrically at about 11 meters from either side of interaction point. They cover the pseudorapidity range 3-5. The length along the beam is 1.65 m or 10 nuclear interaction lengths. Each calorimeter consists of a large steel block that serves as the absorber. Embedded quartz fibers in the steel absorber run parallel to the beam and constitute the active component of the detector. In order to optimize energy resolution for E and E /sup T/ flows and forward jets, the calorimeter is effectively segmented longitudinally by using two different fiber lengths. The present status will be discussed. (6 refs).

  7. Novel investigation of enzymatic biodiesel reaction by isothermal calorimetry

    DEFF Research Database (Denmark)

    Søtoft, Lene Fjerbaek; Westh, Peter; Christensen, Knud V.;

    2010-01-01

    Isothermal calorimetry (ITC) was used to investigate solvent-free enzymatic biodiesel production. The transesterification of rapeseed oil with methanol and ethanol was catalyzed by immobilized lipase Novozym 435 at 40 °C. The aim of the study was to determine reaction enthalpy for the enzymatic...... transesterification and to elucidate the mass transfer and energetic processes taking place. Based on the measured enthalpy and composition change in the system, the heat of reaction at 40 °C for the two systems was determined as −9.8 ± 0.9 kJ/mole biodiesel formed from rapeseed oil and methanol, and −9.3 ± 0.7 k...

  8. Particle flow calorimetry at the international linear collider

    Indian Academy of Sciences (India)

    Mark A Thomson

    2007-12-01

    One of the most important requirements for a detector at the ILC is good jet energy resolution. It is widely believed that the particle flow approach to calorimetry is the key to achieving the goal of $0.3/\\sqrt{E(GeV)}$. This paper describes the current performance of the PandoraPFA particle flow algorithm. For 45 GeV jets in the Tesla TDR detector concept, the ILC jet energy resolution goal is reached. At higher energies the jet energy resolution becomes worse and can be described by the empirical expression: $_{E}/E ≈ 0.265/\\sqrt{E(GeV)} + 1.2 times 10^{-4} E(GeV)$.

  9. Applications of isothermal titration calorimetry in protein science

    Institute of Scientific and Technical Information of China (English)

    Yi Liang

    2008-01-01

    During the past decade,isothermal titration calorimetry (ITC)has developed from a specialist method for understanding molecular interactions and other biological processes within cells to a more robust,widely used method.Nowadays,ITC is used to investigate all types of protein interactions,including protein-protein interactions,protein-DNA/RNA interactions,protein-small molecule interactions and enzyme kinetics;it provides a direct route to the complete thermodynamic characterization of protein interactions.This review concentrates on the new applications of ITC in protein folding and misfolding,its traditional application in protein interactions,and an overview of what can be achieved in the field of protein science using this method and what developments are likely to occur in the near future.Also,this review discusses some new developments of ITC method in protein science,such as the reverse titration of ITC and the displacement method of ITC.

  10. NEUTRON-ENHANCED CALORIMETRY FOR HADRONS (NECH): FINAL REPORT

    Energy Technology Data Exchange (ETDEWEB)

    Andrew Stroud, Lee Sawyer

    2012-08-31

    We present the results of a project to apply scintillator technology recently developed at Louisiana Tech University to hadronic calorimetry. In particular, we developed a prototype calorimeter module incorporating scintillator embedded with metal oxide nanoparticles as the active layers. These metal oxide nanoparticles of gadolinium oxide, have high cross-sections for interactions with slow neutrons. As a part fo this research project, we have developed a novel method for producing plastic scintillators with metal oxide nanoparticles evenly distributed through the plastic without aggregation.We will test the performance of the calorimeter module in test beam and with a neutron source, in order to measure the response to the neutron component of hadronic showers. We will supplement our detector prototyping activities with detailed studies of the effect of neutron component on the resolution of hadronic energy measurements, particular in the next generation of particle flow calorimeters.

  11. A novel photomultiplier tube for calorimetry at the SSC

    International Nuclear Information System (INIS)

    A silicon target photomultiplier tube with an anode consisting of a large area Avalanche Photodiode (APD) has been developed. The tube combines the advantages of an avalanche photodiode, excellent linearity and large dynamic range, with the properties of a phototube. The tube structure is proximity focussing, which is not affected by high magnetic fields approximately aligned with the axis. The high linearity makes this device attractive for calorimetry at the SSC. The extension of this concept to an APD array will provide a cost effective fiber readout for both digital (tracking) and analogue applications. A tube equipped with an APD array is being developed currently as a readout option for the SDC Shower Maximum Detector

  12. Hadronic shower development in Iron-Scintillator Tile Calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Amaral, P.; Amorim, A.; Anderson, K.; Barreira, G.; Benetta, R.; Berglund, S.; Biscarat, C.; Blanchot, G.; Blucher, E.; Bogush, A.; Bohm, C.; Boldea, V.; Borisov, O.; Bosman, M.; Bromberg, C.; Budagov, J.; Burdin, S.; Caloba, L.; Carvalho, J.; Casado, P.; Castillo, M.V.; Cavalli-Sforza, M.; Cavasinni, V.; Chadelas, R.; Chirikov-Zorin, I.; Chlachidze, G.; Cobal, M.; Cogswell, F.; Colaco, F.; Cologna, S.; Constantinescu, S.; Costanzo, D.; Crouau, M.; Daudon, F.; David, J.; David, M.; Davidek, T.; Dawson, J.; De, K.; Del Prete, T.; De Santo, A.; Di Girolamo, B.; Dita, S.; Dolejsi, J.; Dolezal, Z.; Downing, R.; Efthymiopoulos, I.; Engstroem, M.; Errede, D.; Errede, S.; Evans, H.; Fenyuk, A.; Ferrer, A.; Flaminio, V.; Gallas, E.; Gaspar, M.; Gil, I.; Gildemeister, O.; Glagolev, V.; Gomes, A.; Gonzalez, V.; Gonzalez De La Hoz, S.; Grabski, V.; Grauges, E.; Grenier, P.; Hakopian, H.; Haney, M.; Hansen, M.; Hellman, S.; Henriques, A.; Hebrard, C.; Higon, E.; Holmgren, S.; Huston, J.; Ivanyushenkov, Yu.; Jon-And, K.; Juste, A.; Kakurin, S.; Karapetian, G.; Karyukhin, A.; Kopikov, S.; Kukhtin, V.; Kulchitsky, Y.; Kurzbauer, W.; Kuzmin, M.; Lami, S.; Lapin, V.; Lazzeroni, C.; Lebedev, A.; Leitner, R.; Li, J.; Lomakin, Yu.; Lomakina, O.; Lokajicek, M.; Lopez Amengual, J.M.; Maio, A.; Malyukov, S.; Marroquin, F.; Martins, J.P.; Mazzoni, E.; Merritt, F.; Miller, R.; Minashvili, I.; Miralles, Ll.; Montarou, G.; Munar, A.; Nemecek, S.; Nessi, M. E-mail: marzio.nessi@cern.ch; Onofre, A.; Orteu, S.; Park, I.C.; Pallin, D.; Pantea, D.; Paoletti, R.; Patriarca, J.; Pereira, A.; Perlas, J.A.; Petit, P.; Pilcher, J.; Pinhao, J.; Poggioli, L.; Price, L.; Proudfoot, J.; Pukhov, O.; Reinmuth, G.; Renzoni, G.; Richards, R.; Roda, C.; Romance, J.B.; Romanov, V.; Ronceux, B.; Rosnet, P.; Rumyantsev, V.; Russakovich, N.; Sanchis, E.; Sanders, H.; Santoni, C.; Santos, J.; Sawyer, L.; Says, L.-P.; Seixas, J.M.; Sellden, B.; Semenov, A.; Shchelchkov, A.; Shochet, M.; Simaitis, V. [and others

    2000-03-21

    The lateral and longitudinal profiles of hadronic showers detected by a prototype of the ATLAS Iron-Scintillator Tile Hadron Calorimeter have been investigated. This calorimeter presents a unique longitudinal configuration of scintillator tiles. Using a fine-grained pion beam scan at 100 GeV, a detailed picture of transverse shower behaviour is obtained. The underlying radial energy densities for the four depth segments and for the entire calorimeter have been reconstructed. A three-dimensional hadronic shower parametrisation has been developed. The results presented here are useful for understanding the performance of iron-scintillator calorimeters, for developing fast simulations of hadronic showers, for many calorimetry problems requiring the integration of a shower energy deposition in a volume and for future calorimeters design.

  13. Hadronic shower development in Iron-Scintillator Tile Calorimetry

    International Nuclear Information System (INIS)

    The lateral and longitudinal profiles of hadronic showers detected by a prototype of the ATLAS Iron-Scintillator Tile Hadron Calorimeter have been investigated. This calorimeter presents a unique longitudinal configuration of scintillator tiles. Using a fine-grained pion beam scan at 100 GeV, a detailed picture of transverse shower behaviour is obtained. The underlying radial energy densities for the four depth segments and for the entire calorimeter have been reconstructed. A three-dimensional hadronic shower parametrisation has been developed. The results presented here are useful for understanding the performance of iron-scintillator calorimeters, for developing fast simulations of hadronic showers, for many calorimetry problems requiring the integration of a shower energy deposition in a volume and for future calorimeters design

  14. Hadronic Shower Development in Iron-Scintillator Tile Calorimetry

    CERN Document Server

    Amaral, P; Anderson, K; Barreira, G; Benetta, R; Berglund, S; Biscarat, C; Blanchot, G; Blucher, E; Bogush, A A; Bohm, C; Boldea, V; Borisov, O; Bosman, M; Bromberg, C; Budagov, Yu A; Burdin, S; Caloba, L; Carvalho, J; Casado, M P; Castillo, M V; Cavalli-Sforza, M; Cavasinni, V; Chadelas, R; Chirikov-Zorin, I E; Chlachidze, G; Cobal, M; Cogswell, F; Colaço, F; Cologna, S; Constantinescu, S; Costanzo, D; Crouau, M; Daudon, F; David, J; David, M; Davidek, T; Dawson, J; De, K; Del Prete, T; De Santo, A; Di Girolamo, B; Dita, S; Dolejsi, J; Dolezal, Z; Downing, R; Efthymiopoulos, I; Engström, M; Errede, D; Errede, S; Evans, H; Fenyuk, A; Ferrer, A; Flaminio, V; Gallas, E; Gaspar, M; Gil, I; Gildemeister, O; Glagolev, V; Gomes, A; González, V; González de la Hoz, S; Grabskii, V; Graugès-Pous, E; Grenier, P; Hakopian, H H; Haney, M; Hansen, M; Hellman, S; Henriques, A; Hébrard, C; Higón, E; Holmgren, S O; Huston, J; Ivanyushenkov, Yu M; Jon-And, K; Juste, A; Kakurin, S; Karapetian, G V; Karyukhin, A N; Kopikov, S; Kukhtin, V; Kulchitskii, Yu A; Kurzbauer, W; Kuzmin, M; Lami, S; Lapin, V; Lazzeroni, C; Lebedev, A; Leitner, R; Li, J; Lomakin, Yu F; Lomakina, O V; Lokajícek, M; López-Amengual, J M; Maio, A; Malyukov, S; Marroquin, F; Martins, J P; Mazzoni, E; Merritt, F S; Miller, R; Minashvili, I A; Miralles, L; Montarou, G; Munar, A; Némécek, S; Nessi, Marzio; Onofre, A; Orteu, S; Park, I C; Pallin, D; Pantea, D; Paoletti, R; Patriarca, J; Pereira, A; Perlas, J A; Petit, P; Pilcher, J E; Pinhão, J; Poggioli, L; Price, L; Proudfoot, J; Pukhov, O; Reinmuth, G; Renzoni, G; Richards, R; Roda, C; Romance, J B; Romanov, V; Ronceux, B; Rosnet, P; Rumyantsev, V; Rusakovich, N; Sanchis, E; Sanders, H; Santoni, C; Santos, J; Sawyer, L; Says, L P; Seixas, J M; Selldén, B; Semenov, A; Shchelchkov, A S; Shochet, M; Simaitis, V; Sissakian, A N; Solodkov, A; Solovyanov, O; Sonderegger, P; Sosebee, M; Soustruznik, K; Spanó, F; Stanek, R; Starchenko, E A; Stephens, R; Suk, M; Tang, F; Tas, P; Thaler, J; Tokar, S; Topilin, N; Trka, Z; Turcot, A S; Turcotte, M; Valkár, S; Varandas, M J; Vartapetian, A H; Vazeille, F; Vichou, I; Vinogradov, V; Vorozhtsov, S B; Wagner, D; White, A; Wolters, H; Yamdagni, N; Yarygin, G; Yosef, C; Zaitsev, A; Zdrazil, M; Zúñiga, J

    2000-01-01

    The lateral and longitudinal profiles of hadronic showers detected by a prototype of the ATLAS Iron-Scintillator Tile Hadron Calorimeter have been investigated. This calorimeter uses a unique longitudinal configuration of scintillator tiles. Using a fine-grained pion beam scan at 100 GeV, a detailed picture of transverse shower behavior is obtained. The underlying radial energy densities for four depth segments and for the entire calorimeter have been reconstructed. A three-dimensional hadronic shower parametrization has been developed. The results presented here are useful for understanding the performance of iron-scintillator calorimeters, for developing fast simulations of hadronic showers, for many calorimetry problems requiring the integration of a shower energy deposition in a volume and for future calorimeter design.

  15. Local Measurement of Fuel Energy Deposition and Heat Transfer Environment During Fuel Lifetime Using Controlled Calorimetry

    International Nuclear Information System (INIS)

    A comprehensive description of the accomplishments of the DOE grant titled, ''Local Measurement of Fuel Energy Deposition and Heat Transfer Environment During Fuel Lifetime using Controlled Calorimetry''

  16. Thermal characterization of Li/sulfur, Li/ S-LiFePO4 and Li/S-LiV3O8 cells using Isothermal Micro-Calorimetry and Accelerating Rate Calorimetry

    Science.gov (United States)

    Seo, Jeongwook; Sankarasubramanian, Shrihari; Kim, Chi-Su; Hovington, Pierre; Prakash, Jai; Zaghib, Karim

    2015-09-01

    The thermal behavior of three cathode materials for the lithium/sulfur (Li/S) cell, namely - sulfur, sulfur-LiFePO4 (S-LFP) composite and sulfur-LiV3O8 (S-LVO) composite was studied using Isothermal Micro-Calorimetry (IMC) at various discharge rates. A continuum model was used to calculate the reversible entropic heat and irreversible resistive heat generated over the discharge process and the model data was compared to the experimental data to elucidate contributions of reversible and irreversible heats to the overall heat generated during discharge. The reaction enthalpy (ΔHRx) was measured using IMC for each elementary reaction step and in combination with the calculated reversible entropic heat and irreversible resistive heat was fitted against the experimental total heat measurement. The model showed an excellent fit against the experimental data. Further, Accelerating Rate Calorimetry (ARC) was used to study the thermal safety of these three cells. The cell with the S-LVO composite cathode was found to have the highest onset temperature for thermal runaway and also the lowest maximum self-heat rate. Results of this study suggest that S-LVO composite is a promising electrode for Li/S cells.

  17. An Investigation of Thermal Characteristic of Mechanical Crimp Textured Polyester Yarn by Differential Scanning Calorimeter (DSC)

    Science.gov (United States)

    Bhattacharya, Someshwar S.; Shaikh, Tasnim N.; Pratap, Arun

    2010-06-01

    Deficiencies related to the lack of bulk in flat continuous filament yarns make them unsuitable for apparel, home textiles as well as other applications such as car seat covering. Hence, texturising is employed to impart lofty and bulky characteristics to them. The two major texturising techniques employed for polyester yarn are false-twist and air-jet texturising. Out of these earlier technique depends on the thermoplasticity of the yarn being textured whereas the later one demands subsequent amount of compressed air to carry out cold fluid texturising. A new concept of mechanical crimp texturising has been designed to overcome these limitations of commercially successful techniques. In this new technique, pre-twisted FDY (Fully Drawn Yarn) flat multifilament yarn has been subjected to the higher false-twisting (depending on yarn fineness) action under the condition of underfeed (depending on ductility of parent yarn). The torque caused due to high level of false-twisting, forces the filaments to follow helical path at a certain angle (depends on magnitude of twist and denier per filament) to the filament yarn longitudinal axis. Internal stresses arising in single filaments tend to bend the filament and take the shape of spatial helical spring. After the yarn has passed through the false twisting unit, the initial twist would reassert itself and lock the already formed crimpy convolutions in position. Mechanical crimp textured polyester yarns with different pre-twist and false-twist levels have been subjected to thermal stress analysis using differential Scanning Calorimeter (DSC) in heat-cool-heat mode. The samples were heated at a rate of 10°C/minute. Almost all samples appear to be crystalline in nature. However, the melting endotherm does not show sharp peak. Instead, the diffuse nature of the peak is a signature of a partial crystalline nature (48%) of the samples. After melting the specimens, cooling of the same leads to crystallization of the material

  18. Influence of benzene on the Ni{sub 3}Fe nanocrystalline compound formation by wet mechanical alloying: An investigation combining DSC, X-ray diffraction, mass and IR spectrometries

    Energy Technology Data Exchange (ETDEWEB)

    Neamtu, B.V. [Material Science and Technology Department, Technical University of Cluj-Napoca, 103-105 Muncii Avenue, 400641 Cluj-Napoca (Romania); Institut Neel, CNRS/Universite Joseph Fourier, BP 166, 38042 Grenoble, Cedex 9 (France); Isnard, O. [Institut Neel, CNRS/Universite Joseph Fourier, BP 166, 38042 Grenoble, Cedex 9 (France); Chicinas, I., E-mail: Ionel.chicinas@stm.utcluj.ro [Material Science and Technology Department, Technical University of Cluj-Napoca, 103-105 Muncii Avenue, 400641 Cluj-Napoca (Romania); Vagner, C. [Laboratoire Chimie Provence, Universites d' Aix-Marseille I, II et III - CNRS, 13397 Marseille, Cedex 20 (France); Jumate, N. [Material Science and Technology Department, Technical University of Cluj-Napoca, 103-105 Muncii Avenue, 400641 Cluj-Napoca (Romania); Plaindoux, P. [Institut Neel, CNRS/Universite Joseph Fourier, BP 166, 38042 Grenoble, Cedex 9 (France)

    2011-02-15

    Research highlights: {yields} Influence of benzene (PCA) used in wet MA on the powder properties is studied. {yields} Nature of exothermic peak, linked to benzene presence on the particles wet milled. {yields} Adsorbed benzene on the particles during wet milling is decomposed by annealing. {yields} IR and TG-MS studies showed that CO{sub 2}, CO and C are the main fragments obtained. - Abstract: Nanocrystalline Ni{sub 3}Fe powders were obtained via wet mechanical alloying using benzene as surfactant. The differential scanning calorimetry (DSC) measurements showed the presence of an exothermic peak which does not correspond to any phase transformation or phase formation as was proved by X-ray diffraction measurements. The exothermic peak was observed neither for the dry milled samples nor for the wet milled and subsequently annealed powders at 350 deg. C for 4 h. The infra-red (IR) spectra registered for the wet milled samples showed a series of vibration bands corresponding to C{sub 6}H{sub 6} and also to a series of fragments resulting from benzene decomposition. The results obtained by IR investigation were confirmed by thermogravimetry and mass spectrometry (TG + MS) investigations. The main fragments resulting from the benzene decomposition on the surface of the nanocrystalline Ni{sub 3}Fe powders are: CO{sub 2}, CO and C. The evolution of the particle size distribution versus the milling time has been determined for the wet mechanical milling process of nanocrystalline Ni{sub 3}Fe powders. The DSC analysis reveals a displacement of the exothermic peak onset towards lower temperatures and an increase of the surface of this peak attributed to the changes in the particles specific surface and to the quantity of benzene added in the milling experiments.

  19. Thermodynamic study of ibuprofen by adiabatic calorimetry and thermal analysis

    Energy Technology Data Exchange (ETDEWEB)

    Xu Fen; Sun Lixian; Tan Zhicheng; Liang Jianguo; Li Ruilian

    2004-03-23

    Molar heat capacities of ibuprofen were precisely measured with a small sample precision automated adiabatic calorimeter over the temperature range from 80 to 400 K. The polynomial functions of C{sub p,m} (J K{sup -1} mol{sup -1}) versus T were established on the heat capacity measurements by means of the least fitting square method. The functions are as follows: for solid ibuprofen, at the temperature range of 79.105 K{<=}T{<=}333.297 K, C{sub p,m}=144.27+77.046X+3.5171X{sup 2}+10.925X{sup 3}+11.224X{sup 4}, where X=(T-206.201)/127.096; for liquid ibuprofen, at the temperature range of 353.406 K{<=}T{<=}378.785 K, C{sub p,m}=325.79+8.9696X-1.6073X{sup 2}-1.5145X{sup 3}, where X=(T-366.095)/12.690. A fusion transition at T=348.02 K was found from the C{sub p}-T curve. The molar enthalpy and entropy of the fusion transition were determined to be 26.65 kJ mol{sup -1} and 76.58 J mol{sup -1} K{sup -1}, respectively. The thermodynamic functions on the base of the reference temperature of 298.15 K, (H{sub T}-H{sub 298.15}) and (S{sub T}-S{sub 298.15}), were derived. Thermal characteristic of ibuprofen was studied by thermo-gravimetric analysis (TG-DTG) and differential scanning calorimeter (DSC). The temperature of fusion, the molar enthalpy and entropy of fusion obtained by DSC were well consistent with those obtained by adiabatic calorimeter. The evaporation process of ibuprofen was investigated further by TG and DTG, and the activation energy of the evaporation process was determined to be 80.3{+-}1.4 kJ mol{sup -1}.

  20. Experimental investigation of phase equilibria in the Fe–Nb–Si ternary system

    International Nuclear Information System (INIS)

    Highlights: • Three isothermal sections of the Fe–Nb–Si system were experimentally determined. • Some different phase relationships are confirmed in this work. • The solubility of Si in the εNbFe2 phase is about 27.5 at.%, remaining unchanged with the temperature range from 1200 °C to 1000 °C. • The solubility of Si in the μFeNb phase decreases from 14.7 at.% to 10.0 at.% with decrease of temperature from 1200 °C to 1000 °C. - Abstract: The phase equilibria of the Fe–Nb–Si ternary system were investigated by electron probe microanalyzer (EPMA), back scattered electron (BSE), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) on the equilibrated alloys. In this study, three isothermal sections of the Fe–Nb–Si ternary system at 1200 °C, 1100 °C and 1000 °C were respectively determined and six ternary compounds were confirmed. The obtained experimental results show that there are large solubilities of Si in the εNbFe2 and μFeNb phases. The newly determined phase equilibria of the Fe–Nb–Si system will provide useful information for silicon steels development

  1. Experimental and computational study of the thermodynamic properties of 2-nitrofluorene and 2-aminofluorene

    International Nuclear Information System (INIS)

    Highlights: • A thermodynamic study of two fluorene derivatives is presented. • Vapour pressures and energies of combustion were measured. • Enthalpy, entropy and Gibbs energy of sublimation were derived. • Enthalpy and Gibbs energy of formation in crystal and gas phases were calculated. • Gas phase enthalpy of formation was also estimated by quantum chemical calculations. - Abstract: This report presents a comprehensive experimental and computational study of the thermodynamic properties of two fluorene derivatives: 2-aminofluorene and 2-nitrofluorene. The standard (p° = 0.1 MPa) molar enthalpies of formation in the crystalline phase of these compounds were derived from the standard molar energies of combustion, in oxygen, at T = 298.15 K, measured by static bomb combustion calorimetry. A Knudsen effusion method was used to perform the vapour pressure study of the referred compounds, yielding an accurate determination of the standard molar enthalpies and entropies of sublimation. The enthalpies of sublimation were also determined using Calvet microcalorimetry and the enthalpy and temperature of fusion were derived from DSC experiments. Derived results of standard enthalpy and Gibbs energy of formation in both gaseous and crystalline phases were compared with the ones reported in literature for fluorene. A theoretical study at the G3 and G4 levels has been carried out, and the calculated enthalpies of formation have been compared to the experimental values

  2. Change in physical structure of a phenol-spiked sapric histosol observed by Differential Scanning Calorimetry

    Science.gov (United States)

    Ondruch, Pavel; Kucerik, Jiri; Schaumann, Gabriele E.

    2014-05-01

    Interactions of pollutants with soil organic matter (SOM), their fate and transformation are crucial for understanding of soil functions and properties. In past, many papers dealing with sorption of organic and inorganic compounds have been published. However, their aim was almost exceptionally fo-cused on the pollutants themselves, determination of sorption isotherms and influence of external factors, while the change in SOM supramolecular structure was usually ignored. The SOM structure is, however, very important, since the adsorbed pollutant might have a significant influence on soil stability and functions. Differential scanning calorimetry (DSC) represents a technique, which has been successfully used to analyze the physical structure and physico-chemical aging of SOM. It has been found out that water molecules progressively stabilize SOM (water molecule bridge (WaMB)) (Schaumann & Bertmer 2008). Those bridges connect and stabilize SOM and can be disrupted at higher temperature (WaMB transition; (Kunhi Mouvenchery et al. 2013; Schaumann et al. 2013). In the same temperature region melting of aliphatic moieties can be observed (Hu et al. 2000; Chilom & Rice 2005; Kucerik et al. submitted 2013). In this work, we studied the effect of phenol on the physical structure of sapric histosol. Phenol was dissolved in various solvents (water, acetone, hexane, methanol) and added to soils. After the evaporation of solvents by air drying, the sample was equilibrated at 76% relative humidity for 3 weeks. Using DSC, we investigated the influence of phenol on histosol structure and time dependence of melting temperature of aliphatic moieties and WaMB transition. While addition of pure organic solvent only resulted in slightly increased transition temperatures, both melting temperature and WaMB transition temperature were significantly reduced in most cases if phenol was dissolved in these solvents. Water treatment caused a decrease in WaMB transition temperature but

  3. ESTIMATION OF THE CRITICAL RATE OF TEMPERATURE INCREASE OF THERMAL EXPLOSION OF NITROCELLULOSE USING NON-ISOTHERMAL DSC

    Institute of Scientific and Technical Information of China (English)

    Rorng-zu Hu; Peng-jiang Guo; Sheng-li Gao; Hai Zhang; Zhi-ming Xia; Bin-ke Ning; Yan Fang; Qi-zhen Shi; Rong Liu

    2003-01-01

    A method of estimating the critical rate of temperature increase of thermal explosion for the first order autocatalytic decomposition reaction system using non-isothermal DSC is presented. Information is obtained on the increasing rate of temperature in nitrocellulose containing 13.54% of nitrogen when the first order autocatalytic decomposition converts into thermal explosion.

  4. Cerebral perfusion alterations in epileptic patients during peri-ictal and post-ictal phase: PASL vs DSC-MRI.

    Science.gov (United States)

    Pizzini, Francesca B; Farace, Paolo; Manganotti, Paolo; Zoccatelli, Giada; Bongiovanni, Luigi G; Golay, Xavier; Beltramello, Alberto; Osculati, Antonio; Bertini, Giuseppe; Fabene, Paolo F

    2013-07-01

    Non-invasive pulsed arterial spin labeling (PASL) MRI is a method to study brain perfusion that does not require the administration of a contrast agent, which makes it a valuable diagnostic tool as it reduces cost and side effects. The purpose of the present study was to establish the viability of PASL as an alternative to dynamic susceptibility contrast (DSC-MRI) and other perfusion imaging methods in characterizing changes in perfusion patterns caused by seizures in epileptic patients. We evaluated 19 patients with PASL. Of these, the 9 affected by high-frequency seizures were observed during the peri-ictal period (within 5hours since the last seizure), while the 10 patients affected by low-frequency seizures were observed in the post-ictal period. For comparison, 17/19 patients were also evaluated with DSC-MRI and CBF/CBV. PASL imaging showed focal vascular changes, which allowed the classification of patients in three categories: 8 patients characterized by increased perfusion, 4 patients with normal perfusion and 7 patients with decreased perfusion. PASL perfusion imaging findings were comparable to those obtained by DSC-MRI. Since PASL is a) sensitive to vascular alterations induced by epileptic seizures, b) comparable to DSC-MRI for detecting perfusion asymmetries, c) potentially capable of detecting time-related perfusion changes, it can be recommended for repeated evaluations, to identify the epileptic focus, and in follow-up and/or therapy-response assessment. PMID:23623332

  5. A DSC study of deterioration caused by environmental chemical pollutants to parchment, a collagen-based material

    International Nuclear Information System (INIS)

    A DSC study of new parchments exposed at 25 oC for 1-16 weeks to controlled atmospheres containing 50 ppm of gaseous chemical pollutants (NO2, SO2, NO2 + SO2) and 50% relative humidity (RH) was performed. Samples were exposed to chemical pollutants alone, as well as after previous heating at 100 oC for 2-16 days and/or irradiating with visible light (1.7 x 105 lx) for 4-16 h. DSC measurements were performed in both sealed crucibles in static air atmosphere at 25-200 oC and open crucibles under gas flow (nitrogen, oxygen, synthetic air) at 25-280 oC. Analysis of DSC curves provided the variation induced by ageing on the thermodynamic parameters associated with both parchment denaturation and softening of collagen crystalline fraction. All the ageing procedures decreased both temperature and enthalpy of denaturation and increased broadness of DSC peak in function of ageing time. The occurrence of thermal oxidation peaks and/or lower temperature endothermic peaks was observed. The temperature of the first softening peak always indicated a general tendency to decrease as a function of ageing time. Shrinkage temperature of collagen fibres measured by thermomicroscopy also decreased as a result of accelerated ageing treatments.

  6. A DSC study of deterioration caused by environmental chemical pollutants to parchment, a collagen-based material

    Energy Technology Data Exchange (ETDEWEB)

    Budrugeac, Petru [National R and D Institute for Electrical Engineering, INCDIE-ICPE-CA, Splaiul Unirii 313, 030138 Bucharest (Romania); Badea, Elena, E-mail: elena.badea@unito.it [Department of Chemistry IFM, University of Turin, via Pietro Giuria 9, 10125 Torino (Italy); Gatta, Giuseppe Della [Department of Chemistry IFM, University of Turin, via Pietro Giuria 9, 10125 Torino (Italy); Miu, Lucretia [National R and D Institute for Textile and Leather-Div. Leather and Footwear, INCDTP-ICPI, str Ion Minulescu 93, 031215 Bucharest (Romania); Comanescu, Alina [National R and D Institute for Electrical Engineering, INCDIE-ICPE-CA, Splaiul Unirii 313, 030138 Bucharest (Romania)

    2010-03-10

    A DSC study of new parchments exposed at 25 {sup o}C for 1-16 weeks to controlled atmospheres containing 50 ppm of gaseous chemical pollutants (NO{sub 2}, SO{sub 2}, NO{sub 2} + SO{sub 2}) and 50% relative humidity (RH) was performed. Samples were exposed to chemical pollutants alone, as well as after previous heating at 100 {sup o}C for 2-16 days and/or irradiating with visible light (1.7 x 10{sup 5} lx) for 4-16 h. DSC measurements were performed in both sealed crucibles in static air atmosphere at 25-200 {sup o}C and open crucibles under gas flow (nitrogen, oxygen, synthetic air) at 25-280 {sup o}C. Analysis of DSC curves provided the variation induced by ageing on the thermodynamic parameters associated with both parchment denaturation and softening of collagen crystalline fraction. All the ageing procedures decreased both temperature and enthalpy of denaturation and increased broadness of DSC peak in function of ageing time. The occurrence of thermal oxidation peaks and/or lower temperature endothermic peaks was observed. The temperature of the first softening peak always indicated a general tendency to decrease as a function of ageing time. Shrinkage temperature of collagen fibres measured by thermomicroscopy also decreased as a result of accelerated ageing treatments.

  7. Applications of Immersion Calorimetry in Dubinin’s Theory and Electrochemistry

    OpenAIRE

    Stoeckli, Fritz; Centeno, Teresa A.

    2008-01-01

    This study shows that immersion calorimetry is a useful technique which simplifies considerably the analysis of porosity and chemical nature of activated carbons. The characterization of activated carbons in the general theoretical framework of Dubinin's theory with its extensions to calorimetry and adsorption from solutions allows the identification of some key parameters for the performance of these materials in electrochemical capacitors.

  8. Front-End Electronics in calorimetry: from LHC to ILC

    International Nuclear Information System (INIS)

    This report summarizes the electronics developments for liquid argon calorimeter read-out at LHC and the development carried out in the framework of the CALICE collaboration for those of the future linear collider (ILC). It also includes chips designed for multi-anode photomultipliers (MaPMT) used in the OPERA experiment or on ATLAS luminometer, which also find applications in medical imaging. Started in the early 90's, the development for ATLAS calorimetry was extremely challenging in terms of readout speed, radiation tolerance and measurement accuracy. The high speed has required a new approach using current-sensitive preamplifiers instead of charge sensitive ones and the redefinition of noise performance in terms of ENI. The preamplifiers developed at Orsay and the monolithic shapers are described in Chapter 1, including considerations of digital filtering, which was a new technique in our field. Chapter 2 is dedicated to the calibration system, designed and built by Orsay, for which the high performance and accuracy necessitated in-depth studies. The 3. chapter closes the studies for ATLAS with a summary of the detector measurements which had to be carried out on the 200 000 channels in order to understand and model the detector and achieve everywhere the accuracy and uniformity at per-cent level. These developments for ATLAS ended in 2004, although parallel work was also carried out for the NA48 and DO calorimeters which are not detailed here. The next generation of collider will require a new generation of calorimeters, much more granular, referred to as 'imaging calorimetry' with embedded read-out electronics. The ASICs developed for this purpose in the framework of the CALICE collaboration are described in Chapter 4. They integrate all the functionalities of amplification, digitization and read-out making them complex 'System-On-Chip' circuits extremely efficient that find many other applications. A family of 3 chips reads out the Si-W electromagnetic

  9. DSC and TG Analysis of a Blended Binder Based on Waste Ceramic Powder and Portland Cement

    Science.gov (United States)

    Pavlík, Zbyšek; Trník, Anton; Kulovaná, Tereza; Scheinherrová, Lenka; Rahhal, Viviana; Irassar, Edgardo; Černý, Robert

    2016-03-01

    Cement industry belongs to the business sectors characteristic by high energy consumption and high {CO}2 generation. Therefore, any replacement of cement in concrete by waste materials can lead to immediate environmental benefits. In this paper, a possible use of waste ceramic powder in blended binders is studied. At first, the chemical composition of Portland cement and ceramic powder is analyzed using the X-ray fluorescence method. Then, thermal and mechanical characterization of hydrated blended binders containing up to 24 % ceramic is carried out within the time period of 2 days to 28 days. The differential scanning calorimetry and thermogravimetry measurements are performed in the temperature range of 25°C to 1000°C in an argon atmosphere. The measurement of compressive strength is done according to the European standards for cement mortars. The thermal analysis results in the identification of temperature and quantification of enthalpy and mass changes related to the liberation of physically bound water, calcium-silicate-hydrates dehydration and portlandite, vaterite and calcite decomposition. The portlandite content is found to decrease with time for all blends which provides the evidence of the pozzolanic activity of ceramic powder even within the limited monitoring time of 28 days. Taking into account the favorable results obtained in the measurement of compressive strength, it can be concluded that the applied waste ceramic powder can be successfully used as a supplementary cementing material to Portland cement in an amount of up to 24 mass%.

  10. Effect of a bioactive curcumin derivative on DPPC membrane: A DSC and Raman spectroscopy study

    Energy Technology Data Exchange (ETDEWEB)

    Gardikis, Kostantinos [Department of Pharm. Technology, School of Pharmacy, University of Athens, Athens (Greece); Hatziantoniou, Sophia [Department of Pharm. Technology, School of Pharmacy, University of Athens, Athens (Greece); Viras, Kyriakos [Laboratory of Physical Chemistry, Department of Chemistry, University of Athens, Athens (Greece); Demetzos, Costas [Department of Pharm. Technology, School of Pharmacy, University of Athens, Athens (Greece)]. E-mail: demetzos@pharm.uoa.gr

    2006-08-01

    Interactions of dimethoxycurcumin (1) a lipophilic bioactive curcumin derivative with dipalmitoyl phosphatidylcholine (DPPC) were investigated. The thermodynamic changes caused by (1) and its location into DPPC lipid bilayers were monitored by differential scanning calorimetry and Raman spectroscopy. The results reveal that (1) influences the thermotropic properties of DPPC lipid membrane causing abolition of the pretransition and broadening of the phase-transition profile and slightly decreases the T {sub m} at increasing concentrations. The Raman height intensity ratios of the peaks I {sub 2935/2880}, I {sub 2844/2880} and I {sub 1090/1130} are representative of the interaction of (1) with the alkyl chains and furnish information about the ratio between disorder and order that exists in the conformation of the alkyl chain. The intensity changes of the peak at 715 cm{sup -1} indicates interaction between the choline head group and (1). The Raman spectroscopy results are in agreement with the thermal analysis results. Biologically active lipophilic molecules such as (1) should be studied in terms of their interaction with lipid bilayers prior to the development of advanced lipid carrier systems such as liposomes. The results of these studies provide information on the membrane integrity and physicochemical properties that are essential for the rational design lipidic drug delivery systems.

  11. Factors influencing the crystallisation of highly concentrated water-in-oil emulsions: A DSC study

    Directory of Open Access Journals (Sweden)

    Irina Masalova

    2012-03-01

    Full Text Available Highly concentrated emulsions are used in a variety of applications, including the cosmetics, food and liquid explosives industries. The stability of these highly concentrated water-in-oil emulsions was studied by differential scanning calorimetry. Crystallisation of the emulsions was initiated by exposing the emulsions to a low temperature. The effects of surfactant type, electrolyte concentration and electrolyte composition in the aqueous phase on emulsion crystallisation temperature were studied. Surfactant type affected the emulsion crystallisation temperature in the following order: PIBSA-MEA=PIBSA-UREA < PIBSA-MEA/SMO < PIBSA-IMIDE < SMO. These results are in the same sequence as results obtained for the stability of these emulsions in aging studies, that is, PIBSA-MEA was the most stable with age and SMO was the least. The effect of the surfactant type on emulsion crystallisation can probably be attributed to the differing strengths of the surfactant–electrolyte interactions, which result in different molecular packing geometry and differing mobility of the surfactant lipophilic portion at the interface. These results enhance our understanding of the factors that affect the stability of explosive emulsions.

  12. Loading of praziquantel in the crystal lattice of solid lipid nanoparticles - studies by DSC and SAXS

    International Nuclear Information System (INIS)

    Full text: Praziquantel (PZQ) is the drug of choice for oral treatment of schistosomiasis and other fluke infections that affect humans. Its low oral bioavailability demands the development of innovative strategies to overcome the first pass metabolism. In this work, solid lipid nanoparticles loaded with PZQ (PZQ-SLN) were prepared by a modified oil-in-water microemulsion method selecting stearic acid as lipid phase after solubility screening studies. The mean particle size (Z-Ave) and zeta potential (ZP) were 500 nm and -34.0 mV, respectively. Morphology and shape of PZQ-SLN were analysed by scanning electron microscopy revealing the presence of spherical particles with smooth surface. Differential scanning calorimetry suggested that SLN comprised a less ordered arrangement of crystals and the drug was molecularly dispersed in the lipid matrix. No supercooled melts were detected. The entrapment efficiency (EE) and loading capacity of PZQ, determined by high performance liquid chromatography, were 99.0 and 17.5, respectively. Effective incorporation of PZQ into the particles was confirmed by small angle X-ray scattering revealing the presence of a lipid lamellar structure. Stability parameters of PZQ-SLN stored at room temperature (25 deg C) and at 4 deg C were checked by analysing Z-Ave, ZP and the EE for a period of 60 days Results showed a relatively long-term physical stability after storage at 4 deg C, without drug expulsion. (author)

  13. Loading of praziquantel in the crystal lattice of solid lipid nanoparticles - studies by DSC and SAXS

    Energy Technology Data Exchange (ETDEWEB)

    Souza, A.L.R.; Cassimiro, D.L.; Almeida, A.E.; Ribeiro, C.A.; Gremiao, M.P.D. [UNESP, Araraquara, SP (Brazil); Sarmento, V.H.V. [Universidade Federal de Sergipe (UFS), Itabaiana, SE (Brazil); Andreani, T.; Silva, A.M.; Souto, E.B. [Universidade de Tras-os-Montes e Alto Douro, Vila Real (Portugal)

    2012-07-01

    Full text: Praziquantel (PZQ) is the drug of choice for oral treatment of schistosomiasis and other fluke infections that affect humans. Its low oral bioavailability demands the development of innovative strategies to overcome the first pass metabolism. In this work, solid lipid nanoparticles loaded with PZQ (PZQ-SLN) were prepared by a modified oil-in-water microemulsion method selecting stearic acid as lipid phase after solubility screening studies. The mean particle size (Z-Ave) and zeta potential (ZP) were 500 nm and -34.0 mV, respectively. Morphology and shape of PZQ-SLN were analysed by scanning electron microscopy revealing the presence of spherical particles with smooth surface. Differential scanning calorimetry suggested that SLN comprised a less ordered arrangement of crystals and the drug was molecularly dispersed in the lipid matrix. No supercooled melts were detected. The entrapment efficiency (EE) and loading capacity of PZQ, determined by high performance liquid chromatography, were 99.0 and 17.5, respectively. Effective incorporation of PZQ into the particles was confirmed by small angle X-ray scattering revealing the presence of a lipid lamellar structure. Stability parameters of PZQ-SLN stored at room temperature (25 deg C) and at 4 deg C were checked by analysing Z-Ave, ZP and the EE for a period of 60 days Results showed a relatively long-term physical stability after storage at 4 deg C, without drug expulsion. (author)

  14. Transfer kinetics from colloidal drug carriers and liposomes to biomembrane models: DSC studies

    Directory of Open Access Journals (Sweden)

    Maria Grazia Sarpietro

    2011-01-01

    Full Text Available The release of bioactive molecules by different delivery systems has been studied. We have proposed a protocol that takes into account a system that is able to carry out the uptake of a bioactive molecule released during the time, resembling an in vivo-like system, and for this reason we have used biomembrane models represented by multi-lamellar and unilamellar vesicles. The bioactive molecule loaded delivery system has been put in contact with the biomembrane model and the release has been evaluated, to consider the effect of the bioactive molecule on the biomembrane model thermotropic behavior, and to compare the results with those obtained when a pure drug interacts with the biomembrane model. The differential scanning calorimetry technique has been employed. Depending on the delivery system used, our research permits to evaluate the effect of different parameters on the bioactive molecule release, such as pH, drug loading degree, delivery system swelling, crosslinking agent, degree of cross-linking, and delivery system side chains.

  15. Strategies for assessing proton linkage to bimolecular interactions by global analysis of isothermal titration calorimetry data

    International Nuclear Information System (INIS)

    Highlights: ► We demonstrate the usefulness of global analysis of ITC data for proton-linked binding study. ► Various experimental strategies are evaluated for their information content. ► Data at multiple temperatures might improve the precision of binding parameters. ► Methods for detailed error analysis of parameter uncertainties are discussed. ► By global modeling, an uncertainty in molecular concentrations can be accounted for. - Abstract: Isothermal titration calorimetry (ITC) is a traditional and powerful method for studying the linkage of ligand binding to proton uptake or release. The theoretical framework has been developed for more than two decades and numerous applications have appeared. In the current work, we explored strategic aspects of experimental design. To this end, we simulated families of ITC data sets that embed different strategies with regard to the number of experiments, range of experimental pH, buffer ionization enthalpy, and temperature. We then re-analyzed the families of data sets in the context of global analysis, employing a proton linkage binding model implemented in the global data analysis platform SEDPHAT, and examined the information content of all data sets by a detailed statistical error analysis of the parameter estimates. In particular, we studied the impact of different assumptions about the knowledge of the exact concentrations of the components, which in practice presents an experimental limitation for many systems. For example, the uncertainty in concentration may reflect imperfectly known extinction coefficients and stock concentrations or may account for different extents of partial inactivation when working with proteins at different pH values. Our results show that the global analysis can yield reliable estimates of the thermodynamic parameters for intrinsic binding and protonation, and that in the context of the global analysis the exact molecular component concentrations may not be required. Additionally

  16. Adiabatic calorimetry (RSST and VSP) tests with sodium acetate

    Energy Technology Data Exchange (ETDEWEB)

    Kirch, N.W.

    1993-09-01

    As requested in the subject reference, adiabatic calorimetry (RSST and VSP) tests have been performed with sodium acetate covering TOC concentrations from 3 to 7% with the following results: Exothermic activity noted around 200{degrees}C. Propagating reaction initiated at about 300{degrees}C. Required TOC concentration for propagation estimated at about 6 w% (dry mixture) or about 20 w% sodium acetate. Heat of reaction estimated to be 3.7 MJ per kg of sodium acetate (based on VSP test with 3 w% TOC and using a dry mixture specific heat of 1000 J kg{sup {minus}1} K{sup {minus}1}). Based upon the above results we estimate that a moisture content in excess of 14 w% would prevent a propagating reaction of a stoichiometric mixture of fuel and oxidizer ({approximately} 38 w% sodium acetate and {approximately}62 w% sodium nitrate). Assuming that the fuel can be treated as sodium acetate equivalent, and considering that the moisture content in the organic containing waste generally is believed to be in excess of 14 w%, it follows that the possibility of propagating reactions in the Hanford waste tanks can be ruled out.

  17. Applying fast calorimetry on a spent nuclear fuel calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Liljenfeldt, Henrik [Swedish Nuclear Fuel and Waste Management (Sweden); Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Uppsala Univ. (Sweden)

    2015-04-15

    Recently at Los Alamos National Laboratory, sophisticated prediction algorithms have been considered for the use of calorimetry for treaty verification. These algorithms aim to predict the equilibrium temperature based on early data and therefore be able to shorten the measurement time while maintaining good accuracy. The algorithms have been implemented in MATLAB and applied on existing equilibrium measurements from a spent nuclear fuel calorimeter located at the Swedish nuclear fuel interim storage facility. The results show significant improvements in measurement time in the order of 15 to 50 compared to equilibrium measurements, but cannot predict the heat accurately in less time than the currently used temperature increase method can. This Is both due to uncertainties in the calibration of the method as well as identified design features of the calorimeter that limits the usefulness of equilibrium type measurements. The conclusions of these findings are discussed, and suggestions of both improvements of the current calorimeter as well as what to keep in mind in a new design are given.

  18. Isothermal titration calorimetry: A thermodynamic interpretation of measurements

    International Nuclear Information System (INIS)

    Highlights: ► Literature review shows that many ITC utilizations are based on empirical rules. ► A proper and rigorous thermodynamic interpretation of heats of titration is proposed. ► Heats of titration are independent of the cell type using infinitesimal titrations. ► Heats of interaction between solutes require only two different titration runs. - Abstract: Isothermal titration calorimeters have been developed and in use since the 1960s and the number of applications based on empirical rules to use them steadily increases. In this paper a rigorous study of the physical interpretation of the titration heat and the thermodynamic framework underlying isothermal titration calorimetry are proposed. For infinitesimal titrations, the titration heat is independent of the cell type employed, and the interpretation of the titration heat depends on the titrant composition and on the experiment type. Moreover, for the study of the interaction between two solutes in solution, only a combination of two experiments is necessary, and the result is interpreted as the partial enthalpy of interaction at infinite dilution of the solute contained in the titrant solution.

  19. Applying fast calorimetry on a spent nuclear fuel calorimeter

    International Nuclear Information System (INIS)

    Recently at Los Alamos National Laboratory, sophisticated prediction algorithms have been considered for the use of calorimetry for treaty verification. These algorithms aim to predict the equilibrium temperature based on early data and therefore be able to shorten the measurement time while maintaining good accuracy. The algorithms have been implemented in MATLAB and applied on existing equilibrium measurements from a spent nuclear fuel calorimeter located at the Swedish nuclear fuel interim storage facility. The results show significant improvements in measurement time in the order of 15 to 50 compared to equilibrium measurements, but cannot predict the heat accurately in less time than the currently used temperature increase method can. This Is both due to uncertainties in the calibration of the method as well as identified design features of the calorimeter that limits the usefulness of equilibrium type measurements. The conclusions of these findings are discussed, and suggestions of both improvements of the current calorimeter as well as what to keep in mind in a new design are given.

  20. Novel investigation of enzymatic biodiesel reaction by isothermal calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Sotoft, Lene Fjerbaek, E-mail: lfj@kbm.sdu.dk [Institute of Chemical Engineering, Biotechnology and Environmental Technology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M (Denmark); Westh, Peter [Department of Life Science and Chemistry, Roskilde University, PO Box 260, DK-4000 Roskilde (Denmark); Christensen, Knud V.; Norddahl, Birgir [Institute of Chemical Engineering, Biotechnology and Environmental Technology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M (Denmark)

    2010-03-30

    Isothermal calorimetry (ITC) was used to investigate solvent-free enzymatic biodiesel production. The transesterification of rapeseed oil with methanol and ethanol was catalyzed by immobilized lipase Novozym 435 at 40 {sup o}C. The aim of the study was to determine reaction enthalpy for the enzymatic transesterification and to elucidate the mass transfer and energetic processes taking place. Based on the measured enthalpy and composition change in the system, the heat of reaction at 40 {sup o}C for the two systems was determined as -9.8 {+-} 0.9 kJ/mole biodiesel formed from rapeseed oil and methanol, and -9.3 {+-} 0.7 kJ/mole when rapeseed oil and ethanol was used. Simple Michaelis-Menten kinetics was not an appropriate choice for describing the kinetics of this heterogeneous system. The experiments demonstrated the possibility of investigating complex reaction mixtures using ITC. Although it is possible to determine thermodynamic properties such as reaction enthalpy and reaction rate, the difficulty in actually measuring the true non-mass-transfer-limited reaction kinetics is exposed by the high time resolution of ITC.

  1. A microfabrication-based approach to quantitative isothermal titration calorimetry.

    Science.gov (United States)

    Wang, Bin; Jia, Yuan; Lin, Qiao

    2016-04-15

    Isothermal titration calorimetry (ITC) directly measures heat evolved in a chemical reaction to determine equilibrium binding properties of biomolecular systems. Conventional ITC instruments are expensive, use complicated design and construction, and require long analysis times. Microfabricated calorimetric devices are promising, although they have yet to allow accurate, quantitative ITC measurements of biochemical reactions. This paper presents a microfabrication-based approach to integrated, quantitative ITC characterization of biomolecular interactions. The approach integrates microfabricated differential calorimetric sensors with microfluidic titration. Biomolecules and reagents are introduced at each of a series of molar ratios, mixed, and allowed to react. The reaction thermal power is differentially measured, and used to determine the thermodynamic profile of the biomolecular interactions. Implemented in a microdevice featuring thermally isolated, well-defined reaction volumes with minimized fluid evaporation as well as highly sensitive thermoelectric sensing, the approach enables accurate and quantitative ITC measurements of protein-ligand interactions under different isothermal conditions. Using the approach, we demonstrate ITC characterization of the binding of 18-Crown-6 with barium chloride, and the binding of ribonuclease A with cytidine 2'-monophosphate within reaction volumes of approximately 0.7 µL and at concentrations down to 2mM. For each binding system, the ITC measurements were completed with considerably reduced analysis times and material consumption, and yielded a complete thermodynamic profile of the molecular interaction in agreement with published data. This demonstrates the potential usefulness of our approach for biomolecular characterization in biomedical applications. PMID:26655185

  2. Measuring the Kinetics of Molecular Association by Isothermal Titration Calorimetry.

    Science.gov (United States)

    Vander Meulen, Kirk A; Horowitz, Scott; Trievel, Raymond C; Butcher, Samuel E

    2016-01-01

    The real-time power response inherent in an isothermal titration calorimetry (ITC) experiment provides an opportunity to directly analyze association kinetics, which, together with the conventional measurement of thermodynamic quantities, can provide an incredibly rich description of molecular binding in a single experiment. Here, we detail our application of this method, in which interactions occurring with relaxation times ranging from slightly below the instrument response time constant (12.5s in this case) to as large as 600s can be fully detailed in terms of both the thermodynamics and kinetics. In a binding titration scenario, in the most general case an injection can reveal an association rate constant (kon). Under more restrictive conditions, the instrument time constant-corrected power decay following each injection is simply an exponential decay described by a composite rate constant (kobs), from which both kon and the dissociation rate constant (koff) can be extracted. The data also support the viability of this exponential approach, for kon only, for a slightly larger set of conditions. Using a bimolecular RNA folding model and a protein-ligand interaction, we demonstrate and have internally validated this approach to experiment design, data processing, and error analysis. An updated guide to thermodynamic and kinetic regimes accessible by ITC is provided. PMID:26794355

  3. Combined Forward Calorimetry Option for Phase II CMS Endcap Upgrade

    International Nuclear Information System (INIS)

    Traditionally, EM and HAD compartments are thought to be separate and are often optimized individually. However, it is possible to optimize a robust and economical combined calorimeter system for myriad physics objectives. By employing event-by-event compensation afforded by the dual-readout technique, we have shown that excellent jet performance can be attained with a longitudinally un-segmented calorimeter that is calibrated only with electrons. In addition, the linear hadronic energy scale renders complex off-line correction schemes unnecessary. The proposed replacement of the CMS EE and HE calorimeters with a single Combined Forward Calorimeter (CFC) shows excellent jet performance complemented by good EM object detection. In this paper, we give brief snapshots on basic design criteria, timing characteristics of Cherenkov and scintillation pulses, trigger generation criteria and performance under high radiation fields. Although CMS has recently chosen different technologies for its endcap calorimetry in Phase II, the concepts developed here are likely to remain valuable for some time to come

  4. Two decoupling methods for non-isothermal DSC results of AIBN decomposition

    International Nuclear Information System (INIS)

    Highlights: • DSC curves of liquid-state AIBN were obtained by a solvent decoupling method. • A mathematical method was introduced to solve the coupling phenomenon by MATLAB. • The overlapping area of heat absorption and generation was determined. • True characteristic parameters of AIBN’s melting and decomposition were obtained. - Abstract: During thermal decomposition of azobisisobutyronitrile (AIBN), the endothermic process of phase transition disturbed exothermic decomposition, which brought deformation in its thermal graphs. Therefore, exact kinetic parameters of the decomposition could not be obtained by the existing kinetics analytic models, and the accurate enthalpy data of the decomposition and phase transition were not available. Two methods, i.e., a solvent method and a mathematical method, were introduced in this paper to resolve the coupling phenomenon. In the former method, AIBN was dissolved into aniline to eliminate the endothermic process and obtain curves of the liquid-state decomposition. In the latter method, MATLAB software was employed to get the “pure” exothermic decomposition curve without the influence of phase transition by fitting coupling curves within the section after the transition point and extrapolating to the initial stage of decomposition. Moreover, the kinetic parameters of the “pure” exothermic decomposition of AIBN obtained by the mathematical fitting agreed with the results from the solvent method, verifying the accuracy of the decoupling. The research is of great significance for comprehending the exact characteristics of thermal behaviors and safety parameters of AIBN. It also provides a great help to determine the safe operating temperature and alarm temperature for processes in industry

  5. Physical-chemical characterization and stability study of alpha-trypsin at ph 3.0 by differential scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Santos, A.M.C.; Santana, M.A.; Gomide, F.T.F.; Oliveira, J.S.; Vilas Boas, F.A.S.; Santoro, M.M.; Teixera, K.N. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Inst. de Ciencias Biologicas (ICB). Dept. de Bioquimica e Imunologia; Miranda, A.A.C.; Biondi, I. [Universidade Estadual de Feira de Santana (UEFS), BA (Brazil). Dept. de Ciencias Biologicas; Vasconcelos, A.B.; Bemquerer, M.P. [EMBRAPA Recursos Geneticos e Biotecnologia, Brasilia, DF (Brazil). Parque Estacao Biologica (PqEB)

    2008-07-01

    Full text: {alpha}-Trypsin is a serine-protease with a polypeptide chain of 223 amino acid residues and six disulfide bridges. It is a globular protein with predominance of antiparallel {beta}-sheet secondary structure and it has two domains with similar structures. In the present work, a stability study of {alpha}-trypsin in the acid pH range was performed and physical-chemical denaturation parameters were measured by using differential scanning calorimetry (DSC). The {alpha}-trypsin has a shelf-life (t{sub 95%}) of about ten months at pH 3.0 and 4 deg C and its hydrolysis into the {psi}-trypsin isoform is negligible during six months as monitored by mass spectrometry (Micromass Q-ToF). The observed {delta}H{sub cal}/{delta}H{sub vH} ratio is close to unity for {alpha}-trypsin denaturation, which suggests the occurrence of a two-state transition, devoid of molten-globule intermediates. At pH 3.0, {alpha}-trypsin unfolded with T{sub m} 325.9 K and {delta}H= 99.10 kcal mol{sup -1}, and the change in heat capacity between the native and unfolded forms of the protein was estimated to be 1.96 {+-} 0.18 kcal mol{sup -1} K{sup -1}. The stability of {alpha}-trypsin calculated at 298 K and at pH 3.0 was {delta}G{sub U} = 6.10 kcal mol{sup -1}. These values are in the range expected for a small globular protein. These results show that the thermodynamic parameters for unfolding of {beta}-trypsin do not change substantially after its conversion to {alpha}-trypsin.

  6. Measurement of heat capacity and thermal conductivity of HDPE/expanded graphite nanocomposites by differential scanning calorimetry

    Directory of Open Access Journals (Sweden)

    A. Ezan

    2011-07-01

    Full Text Available Purpose: In this study, heat capacity and thermal conductivity of nanocomposites formed by high density polyethylene (HDPE matrix and expanded graphite (EG conductive filling material were investigated.Design/methodology/approach: Nanocomposites containing up to 20 weight percent of expanded graphite filler material were prepared by mixing them in a Brabender Plasticorder. Two grades of expanded graphite fillers were used namely expanded graphite with 5 µm (EG5 and 50 µm (EG50 in diameter. Heat capacity and thermal conductivity of pure HDPE and the nanocomposites were measured using differential scanning calorimetry (DSC.Findings: A substantial increase in thermal conductivity was observed with the addition of expanded graphite to HDPE. Thermal conductivity increased from 0.442 W/m.K for pure HDPE to 0.938 W/m.K for nanocomposites containing 7% by weight of expended graphite. Heat capacity increases with the increase in temperature for both pure HDPE and the nanocomposites filled with expanded graphite and no appreciable difference in the values of heat capacity were detected due to particle size. Heat capacity decreased with increasing graphite particle content for both particle size, following the low of mixtures.Practical implications: Layers of expanded graphite have become of intense interest as fillers in polymeric nanocomposites. Upon mixing the expanded graphite intercalates and exfoliates into nanometer thickness sheets due to their sheet-like structure and week bonds normal to the graphite sheets. That way they have very big surface area and high aspect ratio (200−1500 what results in a formation of percolating network at very low filler content. The nanoparticles usage results in significant improvement in thermal, mechanical, and electrical properties of polymers even with very low loading levels compared with microparticles.Originality/value: To see the effect of conducting fillers on thermal conductivity and heat capacity two

  7. Physical-chemical characterization and stability study of alpha-trypsin at ph 3.0 by differential scanning calorimetry

    International Nuclear Information System (INIS)

    Full text: α-Trypsin is a serine-protease with a polypeptide chain of 223 amino acid residues and six disulfide bridges. It is a globular protein with predominance of antiparallel β-sheet secondary structure and it has two domains with similar structures. In the present work, a stability study of α-trypsin in the acid pH range was performed and physical-chemical denaturation parameters were measured by using differential scanning calorimetry (DSC). The α-trypsin has a shelf-life (t95%) of about ten months at pH 3.0 and 4 deg C and its hydrolysis into the Ψ-trypsin isoform is negligible during six months as monitored by mass spectrometry (Micromass Q-ToF). The observed ΔHcal/ΔHvH ratio is close to unity for α-trypsin denaturation, which suggests the occurrence of a two-state transition, devoid of molten-globule intermediates. At pH 3.0, α-trypsin unfolded with Tm 325.9 K and ΔH= 99.10 kcal mol-1, and the change in heat capacity between the native and unfolded forms of the protein was estimated to be 1.96 ± 0.18 kcal mol-1 K-1. The stability of α-trypsin calculated at 298 K and at pH 3.0 was ΔGU = 6.10 kcal mol-1. These values are in the range expected for a small globular protein. These results show that the thermodynamic parameters for unfolding of β-trypsin do not change substantially after its conversion to α-trypsin

  8. Crystallization kinetics of Fe-B based amorphous alloys studied in-situ using X-rays diffraction and differential scanning calorimetry

    Directory of Open Access Journals (Sweden)

    Santos D.R. dos

    2001-01-01

    Full Text Available The crystallization processes for the amorphous metallic alloys Fe74B17Si2Ni4Mo3 and Fe86B6Zr7Cu1 (at. % were investigated using X-rays diffraction measurements performed in-situ during Joule-heating, with simultaneous monitoring of the electrical resistance. We determined the main structural transitions and crystalline phases formed during heating, and correlated these results to the observed resistance variations. As the annealing current is increased, the resistance shows an initial decrease due to stress relaxation, followed by a drop to a minimum value due to massive nucleation and growth of alpha-Fe nanocrystals. Further annealing causes the formation of small fractions of Fe-B, B2Zr or ZrO2, while the resistance increases due to temperature enhancement. In situ XRD measurements allowed the identification of metastable phases, as the gamma-Fe phase which occurs at high temperatures. The exothermal peaks observed in the differential scanning calorimetry (DSC for each alloy corroborate the results. We also have performed DSC measurements with several heating rates, which allowed the determination of the Avrami exponent and crystallization activation energy for each alloy. The obtained activation energies (362 and 301 kJ/mol for Fe-B-Zr-Cu; 323 kJ/mol for Fe-B-Si-Ni-Mo are comparable to reported values for amorphous iron alloys, while the Avrami exponent values (n = 1.0 or n = 1.2 are consistent with diffusion controlled crystallization processes with nucleation rates close to zero.

  9. Calorimetry at the international linear collider. From simulation to reality

    International Nuclear Information System (INIS)

    Calorimetry plays a crucial role in ongoing and upcoming high-energy physics experiments. To build a powerful calorimetric system with a performance tailored to the expected physics signatures, demands dedicated research and development of new readout technologies as well as dedicated reconstruction algorithms. The presented design of a calorimetric system which meets the high demands of precision physics at the future linear collider ILC, follows the paradigm of particle ow. Particle ow is a reconstruction principle that relies on a calorimetric system with high spatial granularity. In the detector optimisation process, the development of hardware and software are interlinked and cannot be judged independently. This thesis addresses two different aspects of detector optimisation, a test of the detector design against one example physics scenario and the development of a stable calibration procedure. In the rst part, a gauge-mediated Supersymmetry breaking scenario is used to test the design of the electromagnetic calorimeter in a full detector simulation study. The reconstruction of the neutralino properties, each decaying into a photon and a gravitino, requires a good energy resolution, as well as excellent position and angular resolution. The error bounds on the neutralino mass is strongly linked to the energy resolution, while the position and angular reconstruction of neutral particles is essential for the determination of the neutralino lifetime. The second part of this thesis focuses on the calibration procedure for a prototype of the hadron calorimeter. 7608 novel photodetectors are operated and tested in this prototype. They are exposed to beams of well de ned particle type and energy. The calibration is tested with a detailed study of electromagnetic showers inside the cubic-metre-sized prototype, with special attention paid towards the non-linearity correction. (orig.)

  10. Calorimetry at the international linear collider. From simulation to reality

    Energy Technology Data Exchange (ETDEWEB)

    Wattimena, Nanda

    2010-02-15

    Calorimetry plays a crucial role in ongoing and upcoming high-energy physics experiments. To build a powerful calorimetric system with a performance tailored to the expected physics signatures, demands dedicated research and development of new readout technologies as well as dedicated reconstruction algorithms. The presented design of a calorimetric system which meets the high demands of precision physics at the future linear collider ILC, follows the paradigm of particle ow. Particle ow is a reconstruction principle that relies on a calorimetric system with high spatial granularity. In the detector optimisation process, the development of hardware and software are interlinked and cannot be judged independently. This thesis addresses two different aspects of detector optimisation, a test of the detector design against one example physics scenario and the development of a stable calibration procedure. In the rst part, a gauge-mediated Supersymmetry breaking scenario is used to test the design of the electromagnetic calorimeter in a full detector simulation study. The reconstruction of the neutralino properties, each decaying into a photon and a gravitino, requires a good energy resolution, as well as excellent position and angular resolution. The error bounds on the neutralino mass is strongly linked to the energy resolution, while the position and angular reconstruction of neutral particles is essential for the determination of the neutralino lifetime. The second part of this thesis focuses on the calibration procedure for a prototype of the hadron calorimeter. 7608 novel photodetectors are operated and tested in this prototype. They are exposed to beams of well de ned particle type and energy. The calibration is tested with a detailed study of electromagnetic showers inside the cubic-metre-sized prototype, with special attention paid towards the non-linearity correction. (orig.)

  11. Estudo da preparação do catalisador Cp2ZrCl2 suportado em sílica utilizando um planejamento de experimentos Preparation conditions of Cp2ZrCl2 supported on silica using an experimental planning

    Directory of Open Access Journals (Sweden)

    Anunciata Conte

    2001-03-01

    Full Text Available O monômero eteno foi polimerizado através dos sistemas catalíticos Cp2ZrCl2/SiO2 e Cp2ZrCl2/MAO/SiO2. Foi elaborado um planejamento estatístico de experimentos a fim de se identificar as melhores condições de preparo dos catalisadores heterogêneos. As variáveis utilizadas foram a concentração de metilaluminoxano (MAO no pré-tratamento do suporte, a concentração e a temperatura de imobilização do metaloceno. Os catalisadores suportados foram analisados por espectrometria de emissão com plasma acoplado indutivamente e as resinas produzidas foram caracterizadas por cromatografia de permeação em gel (GPC e calorimetria de varredura diferencial (DSC. Foi observado que quanto maior a concentração de zircônio fixada na superfície do suporte, menor foi a atividade catalítica, na faixa de variáveis estudadas.Ethylene was polymerized with the catalytic systems Cp2ZrCl2/SiO2 and Cp2ZrCl2/MAO/SiO2. A experimental planning model was developed in order to identify the best conditions for the preparation of metallocene heterogeneous catalysts. The variables used were methylaluminoxane (MAO concentration of the support treatment, concentration and temperature of metallocene immobilization. The supported catalysts were analyzed by inductively coupled plasma emission spectometry and the polyethylene (PE produced was characterized by gel permeation calorimetry (GPC and differential scanning calorimetry (DSC. It was observed that the higher the zirconium concentration fixed on the support surface, the lower the catalyst activity, in the studied variables range.

  12. The use of DSC curves to determine the acetylation deg.ree of chitin/chitosan samples

    International Nuclear Information System (INIS)

    The use of DSC curves is proposed as an alternative method to determine the deg.ree of N-acetylation (DA) in chitin/chitosan samples, based in both peak area and height of the decomposition signal. Samples with DA from 74 to 16% were prepared from a chitin commercial sample and the DA was determined by 1H NMR, 13C CP/MAS NMR and IR spectra. The effect of water content, heating rate, sample mass and gas flow on the DSC peaks were evaluated and optimized. Using optimized conditions a linear relationship between peak area and height with the DA could be achieved with linear correlation coefficients of -0.998 and -0.999 (n = 7), respectively. The calibration graphs were used to determine the DA of a commercial chitosan sample with relative errors ranging from 2 to 3% for both peak area and peak height, when compared with the DA determined by 1H NMR method

  13. Kinetics of Phase Transformation of Indium in the Presence of Polytetrafluoroethylene: Implications for DSC Measurements on Polymers and Their Composites

    OpenAIRE

    Maria Raimo

    2015-01-01

    The present work focuses on the influence, at nominal constant temperatures, of an inert polymer on the crystallization kinetics of a highly conductive metal as indium (In) to show not only that the presence of a polymer allows obtaining information on the In crystallization directly from differential scanning calorimeter (DSC) curves, but also that appropriate corrections of thermal measurements on low conductivity samples are needed.

  14. Formation of Cholesterol Bilayer Domains Precedes Formation of Cholesterol Crystals in Cholesterol/Dimyristoylphosphatidylcholine Membranes: EPR and DSC Studies

    OpenAIRE

    Mainali, Laxman; Raguz, Marija; Subczynski, Witold K.

    2013-01-01

    Saturation-recovery EPR along with DSC were used to determine the cholesterol content at which pure cholesterol bilayer domains (CBDs) and cholesterol crystals begin to form in dimyristoylphosphatidylcholine (DMPC) membranes. To preserve compositional homogeneity throughout the membrane suspension, lipid multilamellar dispersions were prepared using a rapid solvent exchange method. The cholesterol content increased from 0 to 75 mol%. With spin-labeled cholesterol analogs it was shown that the...

  15. Application of Differential Scanning Calorimetry to Evaluate Thermal Properties and Study of Microstructure of Biodegradable Films

    Science.gov (United States)

    Aguilar-Méndez, M. A.; Martin-Martínez, E. San; Ortega-Arroyo, L.; Cruz-Orea, A.

    2010-03-01

    The glass transition temperature ( T g) and melting temperature ( T m) of gelatin-starch films were determined using differential scanning calorimetry. Also, the microstructure was observed using scanning electron microscopy (SEM) and the crystalline structure by means of X-ray diffraction (XRD). The effect of starch and glycerol concentrations in films on the thermal properties was evaluated through response surface methodology (RSM). The highest values of T m were obtained at starch concentration intervals of (0.26 to 0.54) %w/w and glycerol concentrations lower than 0.5 (%w/w). On the other hand, the T g values diminished as the glycerol concentration increased. Mathematical models for both transitions were fitted to the experimental data. The micrographs obtained by SEM show the influence of glycerol in the microstructure of the films, being more “gummy” as the content of the plasticizer increased. The XRD patterns of the films demonstrate the existence of some pseudo-crystalline regions in the biodegradable materials.

  16. Changes in polymer foils used in food packaging tested by using differential scanning calorimetry

    Indian Academy of Sciences (India)

    J Gajdoš Kljusurić

    2003-12-01

    This work is an experimental study of the differential scanning calorimetry characterisation of polymer materials used in food packaging materials, such as polypropylene (0.03 mm), polyethylene (0.1 and 0.03 mm), poly(D-(-)--hydroxybutyrate) (powder), two-layered polypropylene (0.064 mm), and two-layered polypropylene with poly-vinylidene-chloride (0.012/0.021). The polymer stability was checked by simulation of conditions during food preparation in microwave ovens, sterilisation or rapid freezing. The materials were tested in the temperature range from 40 to 200°C at different scan rates from 2 to 30° C min-1 during heating or cooling. The enthalpies show a high correlation coefficient (0.964) with scan rate. All samples undergo phase change in the temperature range from 107 to 173°C during heating and enthalpies are in the range from 31.8 to 71.1 J g−1 Upon subsequent cooling from 200°C, the temperature range of phase changes is shifted to lower temperatures from 86 to 102°C with enthalpies ranging from 30.4 to 57.8 J g−1. Experiments with exposure of polymers to microwave radiation and freezing prove that the phase change considering the temperature range is very similar in all experiments.

  17. High Temperature Heat Capacity of Alloy D9 Using Drop Calorimetry Based Enthalpy Increment Measurements

    Science.gov (United States)

    Banerjee, Aritra; Raju, S.; Divakar, R.; Mohandas, E.

    2007-02-01

    Alloy D9 is a void-swelling resistant nuclear grade austenitic stainless steel (SS) based on AISI type 316-SS in which titanium constitutes an added predetermined alloying composition. In the present study, the high-temperature enthalpy values of alloy D9 with three different titanium-to-carbon mass percent ratios, namely Ti/C = 4, 6, and 8, have been measured using inverse drop calorimetry in the temperature range from 295 to 1323 K. It is found that within the level of experimental uncertainty, the enthalpy values are independent of the Ti-C mass ratio. The temperature dependence of the isobaric specific heat C P is obtained by a linear regression of the measured enthalpy data. The measured C P data for alloy D9 may be represented by the following best-fit expression: C_P(J \\cdot kg^{-1}\\cdot K^{-1})= 431 + 17.7 × 10^{-2}T + 8.72 × 10^{-5}/T^2. It is found that the measured enthalpy and specific heat values exhibit good agreement with reported data on 316 and other related austenitic stainless steels.

  18. Thermodynamic Study on the Protonation Reactions of Glyphosate in Aqueous Solution: Potentiometry, Calorimetry and NMR spectroscopy.

    Science.gov (United States)

    Liu, Bijun; Dong, Lan; Yu, Qianhong; Li, Xingliang; Wu, Fengchang; Tan, Zhaoyi; Luo, Shunzhong

    2016-03-10

    Glyphosate [N-(phosphonomethyl)glycine] has been described as the ideal herbicide because of its unique properties. There is some conflicting information concerning the structures and conformations involved in the protonation process of glyphosate. Protonation may influence the chemical and physical properties of glyphosate, modifying its structure and the chemical processes in which it is involved. To better understand the species in solution associated with changes in pH, thermodynamic study (potentiometry, calorimetry and NMR spectroscopy) about the protonation pathway of glyphosate is performed. Experimental results confirmed that the order of successive protonation sites of totally deprotonated glyphosate is phosphonate oxygen, amino nitrogen, and finally carboxylate oxygen. This trend is in agreement with the most recent theoretical work in the literature on the subject ( J. Phys. Chem. A 2015, , 119 , 5241 - 5249 ). The result is important because it confirms that the protonated site of glyphosate in pH range 7-8, is not on the amino but on the phosphonate group instead. This corrected information can improve the understanding of the glyphosate chemical and biochemical action. PMID:26862689

  19. Study on the Interaction of Zinc Ion Binding with Human Serum Albumin using Isothermal Titration Calorimetry

    International Nuclear Information System (INIS)

    The interaction between zinc ion and human serum albumin (HSA) was investigated by nano-Watt- scale isothermal titration calorimetry (ITC). From the analysis of the ITC data, the binding characteristics and thermodynamic properties of the system were obtained and the binding mechanism was discussed. It was found that the experimental data fit well with the Langmuir's binding theory and the system behaved as a system with two classes of binding sites (high-affinity and low-affinity binding site). The binding number of high-affinity binding site (N1) is 1.40 and the binding constant (K1) is 2.72*105 L/mol. For the low-affinity binding site, the binding number (N2) is 1.55 and the binding constant (K2) is 3.78*103 L/mol. Moreover, it was indicated by the thermodynamic analysis that the binding processes of both types of binding sites were exothermic and spontaneous. The high-affinity binding was an enthalpy-entropy synergically driven process and the electrostatic interaction was the main force, while the low-affinity binding was an enthalpy driven process and this process was mainly driven by the van der Waals forces. (author)

  20. Ring-shaped Calorimetry Information for a Neural eGamma Identification with ATLAS Detector

    CERN Document Server

    Da Fonseca Pinto, Joao Victor; The ATLAS collaboration; Oliveira Damazio, Denis; Seixas, Jose

    2016-01-01

    \\title{Ring-shaped Calorimetry Information for a Neural e/$\\gamma$ Identification with ATLAS Detector} After the successful operation of the Large Hadron Collider resulting with the discovery of the Higgs boson, a new data-taking period (Run 2) has started. For the first time, collisions are produced with energies of 13 TeV in the centre of mass. It is foreseen the luminosity increase, reaching values as high as $10^{34}cm^{-2}s^{-1}$ yet in 2015. These changes in experimental conditions bring a proper environment for possible new physics key-findings. ATLAS is the largest LHC detector and was designed for general-purpose physics studies. Many potential physics channels have electrons or photons in their final states. For efficient studies on these channels precise measurement and identification of such particles is necessary. The identification task consists of disentangling those particles (signal) from collimated hadronic jets (background). Reported work concerns the identification process based on the cal...

  1. Experimental investigation of phase equilibria in the Cu–Ni–Si ternary system

    International Nuclear Information System (INIS)

    Highlights: •Three isothermal sections of the Cu–Ni–Si system have been investigated. •The ternary compound τ1 and the liquid phase are confirmed at 1073 K. •The γ (Cu5Si) and θ (Ni2Si) phases can be stabilized at higher or lower temperatures. -- Abstract: The phase equilibria in the Cu–Ni–Si ternary system have been investigated experimentally by means of electron probe microanalysis (EPMA), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analysis on equilibrated ternary alloys. Three isothermal sections at 1073, 1173 and 1273 K are determined in the whole composition range. The existence of liquid phase and the ternary compound τ1 is confirmed at 1073 K. The binary γ (Cu5Si), γ (Ni31Si12), δ (Ni2Si) and θ (Ni2Si) phases exhibit a considerable solubility of a third element. In addition, the γ (Cu5Si) and θ (Ni2Si) phases can be stabilized by the addition of Ni and Cu, respectively

  2. Interaction of fullerenol with lysozyme investigated by experimental and computational approaches

    Energy Technology Data Exchange (ETDEWEB)

    Yang Shengtao; Wang Haifang; Guo Lin; Gao Yang; Liu Yuanfang [Beijing National Laboratory for Molecular Sciences, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Cao Aoneng [Institute of Nanochemistry and Nanobiology, Shanghai University, Shanghai 200444 (China)], E-mail: haifangw@pku.edu.cn, E-mail: ancao@shu.edu.cn

    2008-10-01

    The potential biomedical applications of fullerenol C{sub 60}(OH){sub x} (x{approx}24) have been extensively studied. However, the structural information of the interaction of fullerenol with the bio-system at the molecular level, which is essential for understanding its bioactivity and toxicity, is still missing. In this study, lysozyme was selected as a model protein to investigate the interaction between fullerenol and biomolecules. A strong induced circular dichroism (CD) signal of achiral fullerenol was observed after binding with lysozyme. Activity assay shows that lysozyme activity is inhibited significantly by fullerenol. No heat capacity difference between the folded and unfolded states of lysozyme was measured by differential scanning calorimetry (DSC) in the presence of fullerenol, indicating that fullerenol prefers to bind with the hydrophobic residues. Both experimental and Autodock computational results suggest that the binding site on lysozyme for fullerenol is close to Trp 62, and a {pi}-{pi} stacking interaction might play an important role in binding.

  3. Interactions in interesterified palm and palm kernel oils mixtures. II – Microscopy and Differential Scanning Calorimetry

    Directory of Open Access Journals (Sweden)

    Grimaldi, Renato

    2001-12-01

    Full Text Available Palm oil (PO and palm kernel oil (PKO compositions (100/0, 80/20, 60/40, 50/50, 40/60, 20/80 and 0/100 were interesterified in laboratory scale under predetermined conditions (0.4% sodium metoxide, 20 minutes, 100ºC. The fourteen samples, before and after interesterification, were characterized by Polarized Light Microscopy and Differential Scanning Calorimetry (DSC. Results showed the effect of various factors on the form and width of crystals. The mean area of crystals revealed the increase of crystals when PKO was added, with values varying from 2.7 x 10E3 µm2 to PO and 1.8 x 10E6 µm2 to PKO. After interesterification, the crystal widths were lower at PO/PKO 100/0, 80/20, 60/40, 20/80 fractions and were higher to anothers. The beta-prime polimorphic form was observed in the pure palm oil sample. The results showed in melting curves, onset values from –19.6ºC to more unsaturated peaks until 20.7ºC to more saturated ones. The higher values to more saturated peak in a melting curve to palm oil, 38.7 J.g-1 before and 48.4 J.g-1 after interesterification, showed a mores table saturated group. I n a genera l way, t h e interesterification promoted an increase of crystallization rate and a better compatibility between PO/PKO fractions.Fueron interesterificados en el laboratorio mezclas de aceite de palma (PO y aceite de palmiste (PKO en diferentes proporciones (100/0, 80/20, 60/40, 50/50, 40/60, 20/80 y 0/100 bajo condiciones predeterminadas (0.4% metoxido de sodio, 20 minutos, 100ºC. Las catorce muestras fueron caracterizadas antes y después de la interesterificación por Microscopía de Luz Polarizada y por Calorimetría Diferencial de Barrido (DSC. Los resultados mostraron el efecto de varios factores sobre la forma y anchura de los cristales. El área media de los cristales revela el aumento de tamaño de los mismos cuando aumenta la proporción de PKO, con valores que varían entre 2.7 x 10E3 µm2 para PO y 1.8 x 10E

  4. Uranium-liquid argon calorimetry: preliminary results from the DO tests

    International Nuclear Information System (INIS)

    The motivations for using uranium and liquid argon in sampling calorimetry are reviewed and the pros and cons of the technique are discussed. Preliminary results of the DO uranium-liquid argon test program are presented. 9 refs., 7 figs

  5. Local Measurement of Fuel Energy Deposition and Heat Transfer Environment During Fuel Lifetime Using Controlled Calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Don W. Miller; Andrew Kauffmann; Eric Kreidler; Dongxu Li; Hanying Liu; Daniel Mills; Thomas D. Radcliff; Joseph Talnagi

    2001-12-31

    A comprehensive description of the accomplishments of the DOE grant titled, ''Local Measurement of Fuel Energy Deposition and Heat Transfer Environment During Fuel Lifetime using Controlled Calorimetry''.

  6. An Integrated-Circuit Temperature Sensor for Calorimetry and Differential Temperature Measurement.

    Science.gov (United States)

    Muyskens, Mark A.

    1997-01-01

    Describes the application of an integrated-circuit (IC) chip which provides an easy-to-use, inexpensive, rugged, computer-interfaceable temperature sensor for calorimetry and differential temperature measurement. Discusses its design and advantages. (JRH)

  7. The effect of sample mass and heating rate on DSC results when studying the fractional composition and oxidative stability of lube base oils

    Energy Technology Data Exchange (ETDEWEB)

    Shishkin, Yu.L. [Gubkin Russian State University of Oil and Gas, Leninski Prospect 65, 119991 Moscow (Russian Federation)

    2006-05-01

    The method of dynamic microdistillation instrumented through DSC has been further elaborated and validated using distillate and residual base oils as model systems. The two major experimental factors of the method-sample mass and heating rate were varied to determine the optimal (standard) experimental conditions for better fraction resolution and thus more reliable quality assessment of petroleum products (lube oils). If these are increased, the fraction resolution ability of the method is reduced - the lighter fractions evaporate at temperatures close to those of the heavier ones, and generally all the fractions evaporate/oxidize at higher temperatures. Two major types of reactions in the heated sample were identified - the one occurring on the metal surface of the crucible leading to a polymer (lacquer) film formation and the other the oxidative cracking in the bulk of the sample leading to the formation of gaseous products. The extent of the lacquer film formation on the crucible metal surface can be reduced by increasing the heating rate and/or the sample mass, while their reduction results in better fraction resolution. (author)

  8. Relaxation process of Fe(CuNb)SiB amorphous alloys investigated by dynamical calorimetry

    International Nuclear Information System (INIS)

    Differential scanning calorimetry and dynamic differential scanning calorimetry were used to analyze the relaxation process of Fe(CuNb)SiB amorphous alloys. The Curie temperature (TC) evolution of the amorphous phase during relaxation as a function of heating rate, time and pre-annealing temperature were measured. Two distinct relaxation processes are observed, consequent with topological and chemical short range order changes. copyright 1997 American Institute of Physics

  9. Relaxation process of Fe(CuNb)SiB amorphous alloys investigated by dynamical calorimetry

    OpenAIRE

    Zhu, J.; Clavaguera-Mora, M. T.; Clavaguera, N.

    1997-01-01

    Differential scanning calorimetry and dynamic differential scanning calorimetry were used to analyze the relaxation process of Fe(CuNb)SiB amorphous alloys. The Curie temperature(TC) evolution of the amorphous phase during relaxation as a function of heating rate, time and pre-annealing temperature were measured. Two distinct relaxation processes are observed, consequent with topological and chemical short range order changes.

  10. INDIRECT CALORIMETRY IN THE ASSESSMENT OF THE ENERGY REQUIREMENT IN OVERWEIGHT AND OBESE WOMEN

    OpenAIRE

    Ewa Lange; Dominika Głąbska; Dariusz Włodarek

    2013-01-01

    Individual total energy expenditure may be calculated as a sum of basal energy requirement and energy expenditure associated with physical activity. Measurement of basal energy requirement is not often conducted in dietetic practice, but may be applied using indirect calorimetry. The aim of the analysis was to present the possibilities of using the Fitmate PRO monitor in the assessment of resting metabolic rate and basal energy expenditure with a method of indirect calorimetry in a group of 9...

  11. Isobaric specific heat capacity of typical lithium chloride liquid desiccants using scanning calorimetry

    International Nuclear Information System (INIS)

    Highlights: • Typical lithium chloride liquid desiccants were concerned. • Up to date heat capacity data of high quality were measured. • Scanning calorimetry technology was applied. • A universal empirical formula was correlated for the heat capacity of solutions. -- Abstract: Three kinds of lithium chloride desiccants were selected, which are considered to be potential and interesting working fluids for a desiccant/dehumidification or absorption refrigeration system, and their isobaric specific heat capacities were determined in this context. Experiments were conducted at a high accuracy twin-cell scanning calorimeter. The temperature accuracy and heat flux resolution of the calorimeter are ±0.05 K and 0.1 μW respectively. The data of lithium chloride + water and lithium chloride + triethylene glycol (TEG)/propylene glycol (PG) + water systems were achieved at temperatures from 308.15 K to 343.15 K and atmospheric pressure. The mass fraction of LiCl ranged from 15% to 45% in the LiCl + H2O system, and the mass fraction of LiCl and glycol ranged from 10% to 23.3% and 20% to 46.7% in the ternary systems respectively. Based on the experimental heat capacity data, a universal empirical formula was correlated as a function of temperature and solute mass fraction. In the experimental mass fractions and temperatures range, the average absolute deviation (AAD) between experiment results and calculated values is no more than 0.15%, and maximum absolute deviation (MAD) is within 0.38%. These thermodynamic data of lithium chloride solutions can be effectively used for analysis and design of desiccant/dehumidification systems and absorption refrigeration systems in both refrigeration and chemical industry

  12. Dimyristoylphosphatidylcholine/C16 : 0-ceramide binary liposomes studied by differential scanning calorimetry and wide- and small-angle X-ray scattering

    DEFF Research Database (Denmark)

    Holopainen, J.M.; Lemmich, J.; Richter, F.; Mouritsen, O.G.; Rapp, G.; Kinnunen, P.K.J.

    2000-01-01

    hydrated binary membranes composed of dimyristoylphosphatidylcholine (DMPC) and N-palmitoyl-ceramide (C16:0-ceramide, up to a mole fraction X-cer = 0.35) were resolved in further detail by high-sensitivity differential scanning calorimetry (DSC) and x-ray diffraction. Both methods reveal very strong...... studied compositions there is an endotherm in the region close to the T-m for DMPC. At X-cer greater than or equal to 0.03 a second endotherm is evident at higher temperatures, starting at 32.1 degrees C and reaching 54.6 degrees C at X-cer = 0.30. X-ray small-angle reflection heating scans reveal a...... lamellar phase within the temperature range of 15-60 degrees C, regardless of composition. The pretransition is observed up to X-cer < 0.18, together with an increase in T-p. In the gel phase the lamellar repeat distance d increases from similar to 61 Angstrom at X-cer = 0.03, to 67 Angstrom at X-cer = 0...

  13. Establishment of Heat Treatment Process for Modified 440A Martensitic Stainless Steel Using Differential Scanning Calorimetry and Thermo-Calc Calculation

    Directory of Open Access Journals (Sweden)

    Huei-Sen Wang

    2015-12-01

    Full Text Available To provide a suitable microstructure and mechanical properties for modified Grade 440A martensitic stainless steel (MSS, which could facilitate the further cold deformation process (e.g., cold rolling, this work used differential scanning calorimetry (DSC and Thermo-Calc software to determine three soaking temperatures for annealing heat treatment processes (HT1, HT2 and HT3. To verify the feasibility of the proposed annealing heat treatment processes, the as-received samples were initially heated to 1050 °C (similar to the on-line working temperature for 30 min and air quenched to form a martensitic structure. The air-quenched samples were then subjected to three developed annealing heat treatment conditions. The microstructure and mechanical properties of the heat-treated samples were then investigated. Test results showed that considering the effects of the microstructure and the hardness, the HT1, the HT2 or the soaking temperatures between the HT1 and HT2 were the most recommended processes to modified Grade 440A MSS. When using the recommended processes, their carbides were fine and more evenly distributed, and the microhardness was as low as 210 Hv, which can be applied to the actual production process.

  14. Thermophysical properties of solid phase ruthenium measured by the pulse calorimetry technique over a wide temperature range

    Energy Technology Data Exchange (ETDEWEB)

    Milosevic, Nenad; Nikolic, Ivana [Belgrade Univ. (Serbia). Vinca Institute of Nuclear Sciences

    2015-04-15

    This paper presents experimental results on four thermophysical properties of pure polycrystalline ruthenium samples over a wide temperature range. Specific heat capacity and specific electrical resistivity were measured from 250 to 2 500 K, while hemispherical total emissivity and normal spectral emissivity at 900 nm were measured from 1 300 to 2 500 K. All the properties were obtained by using the pulse calorimetry technique. The 200 mm long specimens were in the form of a thin rod, of about 3 mm in diameter. For necessary corrections, literature data on thermal linear expansion were applied. The results are compared with available literature data and discussed. The specific heat capacity and specific electrical resistivity measurements did not indicate any allotropic transformation of the samples over the entire temperature range.

  15. Incorporación de materiales de cambio de fase en placas de yeso para almacenamiento de energía térmica mediante calor latente: caracterización térmica del material mediante la técnica DSC

    Directory of Open Access Journals (Sweden)

    Oliver, A.

    2011-06-01

    Full Text Available Differential Scanning Calorimetry (DSC is a thermal analysis technique which has been used for more than three decades to measure the temperatures and heat flows associated with transitions in materials as a function of time. Other techniques, are Differential Thermal Analysis DTA and Conventional Calorimetry. There is great uncertainty in the values supplied by the manufacturers (because they are referred to pure substances and the DSC should be used to get more accurate values. It will be analyzed the thermal storage capacity depending on temperature for several compound materials formed by some aggregates, mainly gypsum and phase change materials, in various proportions. The results have been compared with other building materials such as gypsum boards and brick layer. The suitability of the new construction material for thermal energy storage will be assessed in comparison with other materials traditionally used for this purpose.

    La Calorimetría Diferencial de Barrido es una técnica de análisis térmico, usada desde hace décadas, para medir la entalpía asociada al cambio de fase de un material como función del tiempo y de la temperatura. Otras técnicas menos utilizadas son la Calorimetría Convencional el Análisis Térmico Diferencial. Existe una gran incertidumbre en los valores de propiedades suministrados por los fabricantes (puesto que éstos se refieren a las sustancias puras y es conveniente utilizar DSC para tener valores más exactos. Se va a analizar la capacidad de almacenamiento térmico en función de la temperatura de varios materiales compuestos formados por los mismos agregados -principalmente yeso y material de cambio de fase- en distintas proporciones. Los valores obtenidos se comparan con otros materiales constructivos, yeso laminado y ladrillo. También se verifica la idoneidad del nuevo material constructivo para el almacenamiento de energía térmica frente a otros materiales utilizados

  16. Evaluation of the amorphous content of lactose by solution calorimetry and Raman spectroscopy.

    Science.gov (United States)

    Katainen, Erja; Niemelä, Pentti; Harjunen, Päivi; Suhonen, Janne; Järvinen, Kristiina

    2005-11-15

    Solution calorimetry can be used to determine the amorphous content of a compound when the solubility and dissolution rate of the compound in the chosen solvent are reasonably high. Sometimes, it can be difficult find a solvent in which a sample is freely soluble. The present study evaluated the use of solution calorimetry for the assessment of the amorphous content of a sample that is poorly soluble in a solvent. Physical mixtures of lactose and spray-dried lactose samples (the amorphous content varied from 0 to 100%) were analyzed by a solution calorimeter and the results were compared with Raman spectroscopy determinations. The heat of solvation of the samples was determined by solution calorimetry in organic solvents MeOH, EtOH, ACN, THF, acetone (400mg sample/100ml solvent). Lactose is virtually insoluble in ACN, THF and acetone and very slightly soluble in EtOH and MeOH. The amorphous content of the samples could not be determined by solution calorimetry in EtOH, ACN, THF or acetone. However, an excellent correlation was observed between the heat of solvation and the amorphous content of the samples in MeOH. Furthermore, the heat of solvation values of the samples in MeOH showed a linear correlation with the Raman quantifications. Therefore, our results demonstrate that solution calorimetry may represent a rapid and simple method for determining the amorphous content also in samples that are not freely soluble in the solvent. PMID:18970276

  17. Engineering design of dosimeter prototype based on graphite calorimetry for electron radiation dose measurement

    International Nuclear Information System (INIS)

    he engineering design of a dosimeter prototype based on graphite calorimetry for electron radiation dose measurement at electron energy of at most 300 keV and maximum dose of 60 kGy have been carried out. The graphite core is a cylinder shape with diameter and thickness of 30 mm and 2 mm respectively, surrounded by a guard ring made of the same graphite material. Dosimeter based on graphite calorimetry is equipped with a styrofoam for thermal insulation, temperature sensors and instrumentation based on micro controller. The characteristics of dosimeter based on graphite calorimetry are obtained by means of calculation and computer simulations using Penelope 2003 software and ANSYS computer program. The dosimeter based on graphite calorimetry has been designed to perform real time measurement of the average of absorbed and surface dose, it was expected that dosimeter based on graphite calorimetry can operate well. Compared with the cellulose tri acetate (CTA) dose measurement it gives relative differences of 18.9% and 9.1% at the experiments of energy variation and electron beam current alteration of the electron beam machine (EBM) respectively. (author

  18. Direct measurement of absorbed dose to water in HDR 192Ir brachytherapy: Water calorimetry, ionization chamber, Gafchromic film, and TG-43

    International Nuclear Information System (INIS)

    Purpose: Gafchromic film and ionometric calibration procedures for HDR 192Ir brachytherapy sources in terms of dose rate to water are presented and the experimental results are compared to the TG-43 protocol as well as with the absolute dose measurement results from a water calorimetry-based primary standard. Methods: EBT-1 Gafchromic films, an A1SL Exradin miniature Shonka thimble type chamber, and an SI HDR 1000 Plus well-type chamber (Standard Imaging, Inc., Middleton, WI) with an ADCL traceable Sk calibration coefficient (following the AAPM TG-43 protocol) were used. The Farmer chamber and Gafchromic film measurements were performed directly in water. All results were compared to direct and absolute absorbed dose to water measurements from a 4 deg. C stagnant water calorimeter. Results: Based on water calorimetry, the authors measured the dose rate to water to be 361±7 μGy/(h U) at a 55 mm source-to-detector separation. The dose rate normalized to air-kerma strength for all the techniques agree with the water calorimetry results to within 0.83%. The overall 1-sigma uncertainty on water calorimetry, ionization chamber, Gafchromic film, and TG-43 dose rate measurement amounts to 1.90%, 1.44%, 1.78%, and 2.50%, respectively. Conclusions: This work allows us to build a more realistic uncertainty estimate for absorbed dose to water determination using the TG-43 protocol. Furthermore, it provides the framework necessary for a shift from indirect HDR 192Ir brachytherapy dosimetry to a more accurate, direct, and absolute measurement of absorbed dose to water.

  19. EVOLVED GAS ANALYSIS (COUPLED TG-DSC-FT-IR APPLIED IN THE STUDY OF FRUCTOOLIGOSACCHARIDES FROM CHICORY

    Directory of Open Access Journals (Sweden)

    Roberta de Souza Leone

    2014-08-01

    Full Text Available EGA (Evolved Gas Analysis is a group of coupled techniques (in this case TG-DSC and FT-IR that was used to provide information about the thermal and calorimetric behavior of standard fructooligosaccharides (FOS from chicory. These FOS are found in several foods (tuber, roots, fruits, leaves, cereals, etc. and have been the subject of several studies. In the present study thermogravimetry (TG allowed the characterization of FOS a standard (Sigma-Aldrich, in which the weight loss can be observed in three stages (m 7.56, 55.53 and 36.53%, respectively. The simultaneous use of DSC showed endo and exothermic events in temperature characteristics and in agreement with TG curves. The enthalpies of the main stages of decomposition were calculated: ΔHdehydr 260 J g-1 and ΔHdec 410 J g-1. From the FT-IR spectrum of the volatiles was possible to characterize the main bands, which confirmed CO and CO2 as a result of thermal decomposition.

  20. Looking for the interactions between omeprazole and amoxicillin in a disordered phase. An experimental and theoretical study

    Science.gov (United States)

    Russo, Marcos G.; Sancho, Matias I.; Silva, Lorena M. A.; Baldoni, Hector A.; Venancio, Tiago; Ellena, Javier; Narda, Griselda E.

    2016-03-01

    In this paper, co-grinding mixtures of omeprazole-amoxicillin trihydrate (CGM samples) and omeprazole-anhydrous amoxicillin (CGMa samples) at 3:7, 1:1 and 7:3 molar ratios, respectively, were studied with the aim of obtaining a co-amorphous system and determining the potential intermolecular interactions. These systems were fully characterized by differential scanning calorimetry (DSC), FT-infrared spectroscopy (FTIR), X-ray powder diffraction (PXRD), scanning electron microscopy (SEM) and solid state Nuclear Magnetic Resonance (ssNMR). The co-grinding process was not useful to get a co-amorphous system but it led to obtaining the 1:1 CGMa disordered phase. Moreover, in this system both FTIR and ssNMR analysis strongly suggest intermolecular interactions between the sulfoxide group of omeprazole and the primary amine of amoxicillin anhydrous. The solubility measurements were performed in simulated gastric fluid (SGF) to prove the effect of the co-grinding process. Complementarily, we carried out density functional theory calculations (DFT) followed by quantum theory of atoms in molecules (QTAIM) and natural bond orbital (NBO) analyses in order to shed some light on the principles that guide the possible formation of heterodimers at the molecular level, which are supported by spectroscopic experimental findings.

  1. Experimental study of partially-cured Z-pins reinforced foam core composites: K-Cor sandwich structures

    Directory of Open Access Journals (Sweden)

    Zheng Yingying

    2014-02-01

    Full Text Available This paper presents an experimental study of a novel K-Cor sandwich structure reinforced with partially-cured Z-pins. The influence of pultrusion processing parameters on Z-pins characteristics was studied and the effect of Z-pins on mechanical properties was disclosed. Differential scanning calorimetry (DSC and optical microscopy (OM methods were employed to determine the curing degree of as-prepared Z-pins and observe the implanted Z-pins in the K-Cor structure. These partially-cured Z-pins were treated with a stronger bonding link between face sheets and the foam core by means of a hot-press process, thereby decreasing burrs and cracking defects when the Z-pins were implanted into the Rohacell foam core. The results of the out-of-plane tensile tests and the climbing drum peel (CDP tests showed that K-Cor structures exhibited superior mechanical performance as compared to X-Cor and blank foam core. The observed results of failure modes revealed that an effective bonding link between the foam core and face sheets that was provided from partially-cured Z-pins contributed to the enhanced mechanical performances of K-Cor sandwich structures.

  2. Experimental study of partially-cured Z-pins reinforced foam core composites:K-Cor sandwich structures

    Institute of Scientific and Technical Information of China (English)

    Zheng Yingying; Xiao Jun; Duan Mufeng; Li Yong

    2014-01-01

    This paper presents an experimental study of a novel K-Cor sandwich structure rein-forced with partially-cured Z-pins. The influence of pultrusion processing parameters on Z-pins characteristics was studied and the effect of Z-pins on mechanical properties was disclosed. Differential scanning calorimetry (DSC) and optical microscopy (OM) methods were employed to determine the curing degree of as-prepared Z-pins and observe the implanted Z-pins in the K-Cor structure. These partially-cured Z-pins were treated with a stronger bonding link between face sheets and the foam core by means of a hot-press process, thereby decreasing burrs and cracking defects when the Z-pins were implanted into the Rohacell foam core. The results of the out-of-plane tensile tests and the climbing drum peel (CDP) tests showed that K-Cor structures exhibited superior mechanical performance as compared to X-Cor and blank foam core. The observed results of failure modes revealed that an effective bonding link between the foam core and face sheets that was provided from partially-cured Z-pins contributed to the enhanced mechan-ical performances of K-Cor sandwich structures.

  3. DSC及IR联合测定环氧树脂-双氰胺体系固化工艺参数%Determination of Curing Parameter for Epoxy Resin-Dicyandiamide System by DSC and IR

    Institute of Scientific and Technical Information of China (English)

    蔡晋; 董如林; 陈智栋; 金长春; 方敏

    2011-01-01

    The effect of the amount of dicyandiamide on the curing reaction of epoxy resin has been investigated , using non-isothermal DSC method and the reaction kinetics of the epoxy resin -dicyandiamide system has been studied, using DSC curves measured at different heating rates. Simultaneously, the optimum curing condition has been established , using DSC and IR analytical technique. The experimental results indicate that the optimum amount of dicyandiamide is 5. 6%, curing temperature 403K and curing time 70 min. The activation energy and reaction rate for the curing reaction of the epoxy resin-dicyandiamide system were calculated to be 96. 82 Kj/mol and 0. 93, respectively.%采用非等温DSC法研究了固化剂用量对环氧树脂固化反应的影响,同时利用不同升温速率下测得的DSC曲线研究了环氧树脂-双氰胺体系的固化反应动力学,并由DSC及IR分析技术确定了该体系的最佳反应条件.实验结果表明:固化剂双氰胺最佳用量为5.6%,最佳固化温度为403 K,固化时间为70 min,该体系的反应活化能为96.82 kJ/mol,反应级数为0.93.

  4. Papel del agua en la gelatinización delalmidón de maíz: estudio por calorimetríadiferencial de barrido Role of water in maize starch gelatinization: an study by Differential Scanning Calorimetry

    Directory of Open Access Journals (Sweden)

    P. Pineda–Gómez

    2010-06-01

    Full Text Available El comportamiento térmico del almidón de maíz (Sigma Aldrich se estudió através de calorimetría diferencial de barrido (DSC. El pico endotérmico observadoen el perfil DSC se asocia al proceso de transición de gelatinizacióndel almidón. La fase inicial del proceso y el rango en el que éste ocurre, está gobernada principalmente por la concentración del almidón en solución. Enesta investigación se demuestra que los parámetros relacionados con el métodode observación, en un análisis de DSC influyen al momento de determinar lagelatinización del almidón de maíz. De esta forma, la temperatura del picode transición, la entalpía de gelatinización y el intervalo de temperatura degelatinización son los parámetros en estudio cuando se varía la humedad dela muestra y velocidad de calentamiento con un tamaño de grano homogéneo.Para los análisis, se tomaron valores de humedad de 60, 65, 70, 75 y 80%(p/p, para una velocidad de calentamiento de 2, 5 y 10◦C/min. De igualmodo, para un valor fijo de humedad (80%, se utilizó una velocidad de calentamientode 2, 5, 7, 10 y 15◦C/min. Los resultados indican que la cantidad deagua influye significativamente sobre la entalpía de gelatinización del proceso,pero la temperatura del pico Tp de la endoterma se mantiene constante. Elvalor de la entalpía disminuye a medida que la cantidad de agua aumenta.Las variaciones también son dependientes de la rapidez con que se efectúa latransformación. Los análisis permitieron corroborar, que esta transición en elalmidón es dependiente de factores extrínsecos durante el proceso. Este conocimientosobre la gelatinización del almidón es útil para optimizar procesosindustriales derivados de éste.The thermal behavior of corn starch (Sigma Aldrich was studied by differential scanning calorimetry (DSC. The endothermic peak in the DSC thermogram is associated to the starch gelatinization transition process. Initial phase of process and range in

  5. Optical fibre temperature sensor technology and potential application in absorbed dose calorimetry

    International Nuclear Information System (INIS)

    Optical fibre based sensors are proposed as a potential alternative to the thermistors traditionally used as temperature sensors in absorbed dose calorimetry. The development of optical fibre temperature sensor technology over the last ten years is reviewed. The potential resolution of various optical techniques is assessed with particular reference to the requirements of absorbed dose calorimetry. Attention is drawn to other issues which would require investigation before the development of practical optical fibre sensors for this purpose could occur. 192 refs., 5 tabs., 4 figs

  6. Temperature-modulated differential scanning calorimetry as a specific heat spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Carpentier, L.; Descamps, M. [Laboratoire de Dynamique et Structures des Materiaux Moleculaires, ESA CNRS 8024, Universite de Lille, Villeneuve d' Ascq (France)]. E-mails: Marc.Descamps@univ-lille1.fr; Laurent.Carpentier@univ-lille1.fr; Bustin, O. [Laboratoire de Dynamique et Structures des Materiaux Moleculaires, ESA CNRS 8024, Universite de Lille, Villeneuve d' Ascq (France)

    2002-02-21

    The ability of modulated differential scanning calorimetry (MDSC) technique to perform a specific heat spectroscopy is examined by comparing MDSC results with those of alternating current calorimetry technique. The comparison is performed on three glass formers: glycerol, propylene glycol and salol. Both techniques give rise to similar activation energies, fragility index m and non-exponential parameters {beta} for the different compounds. It shows the relevance of the MDSC technique in providing a convenient laboratory probe of the molecular mobility. MDSC data are also compared with available dielectric results. This allows a check on the consistency of the results with regard to the differences between calorimetric and dielectric analysis. (author)

  7. Temperature-modulated differential scanning calorimetry as a specific heat spectroscopy

    Science.gov (United States)

    Carpentier, L.; Bustin, O.; Descamps, M.

    2002-02-01

    The ability of modulated differential scanning calorimetry (MDSC) technique to perform a specific heat spectroscopy is examined by comparing MDSC results with those of alternating current calorimetry technique. The comparison is performed on three glass formers: glycerol, propylene glycol and salol. Both techniques give rise to similar activation energies, fragility index m and non-exponential parameters β for the different compounds. It shows the relevance of the MDSC technique in providing a convenient laboratory probe of the molecular mobility. MDSC data are also compared with available dielectric results. This allows a check on the consistency of the results with regard to the differences between calorimetric and dielectric analysis.

  8. Temperature-modulated differential scanning calorimetry as a specific heat spectroscopy

    International Nuclear Information System (INIS)

    The ability of modulated differential scanning calorimetry (MDSC) technique to perform a specific heat spectroscopy is examined by comparing MDSC results with those of alternating current calorimetry technique. The comparison is performed on three glass formers: glycerol, propylene glycol and salol. Both techniques give rise to similar activation energies, fragility index m and non-exponential parameters β for the different compounds. It shows the relevance of the MDSC technique in providing a convenient laboratory probe of the molecular mobility. MDSC data are also compared with available dielectric results. This allows a check on the consistency of the results with regard to the differences between calorimetric and dielectric analysis. (author)

  9. Analysis of calorimetry in ultra relativistic heavy ion collisions at 200 GeV per nucleon

    International Nuclear Information System (INIS)

    We draw up in this thesis the statement of the calorimetry analysis in ultra relativistic heavy ion collisions at 200 GeV/A. NA38 experiment studies the production of dimuons correlated with neutral transverse energy flow detected by an electromagnetic calorimeter. J/Ψ suppression in central collisions could be a signature of the quark-gluon plasma (Q.G.P.). Characteristics and limits of the apparatus are briefly described. On the other hand, calorimetry measurements and analysis methods are studied in details and future developments are proposed

  10. DSC/TG-MS联用技术研究CL-20与NC-NG体系的相互作用%Research on the Interaction between CL-20 and NC-NG System via DSC/TG-MS

    Institute of Scientific and Technical Information of China (English)

    常海

    2007-01-01

    应用DSC/TG-MS联用新技术研究了CL-20与NC/NG双基混合体系的相互作用,在溶解制样条件下,NC/NG体系与CL-20不仅有物理相互作用,还有明显的化学相互作用,表现为:CL-20的存在,使得NG的升华过程和CL-20的分解过程显著提前,NC/NG体系的分解过程滞后;并研究了不同粒度的CL-20的热失重过程,表现为大颗粒CL-20热分解过程中有两次明显的热失重,小颗粒CL-20为一次热失重.

  11. DSC/TG-FTIR-MS联用技术研究ADN热分解动力学和机理%Research on the kinetics and mechanism of the thermal decomposition of ADN via DSC/TG-MS-FTIR

    Institute of Scientific and Technical Information of China (English)

    王晓红; 张皋; 赵凤起; 谢明召; 任晓宁; 何少蓉

    2010-01-01

    应用DSC/TG-MS-FTIR同步热分析-红外质谱联用技术,研究了ADN的分解过程及分解机理,从ADN分解生成的气体产物的动态分布及气体产物的生成动力学方面,获得了ADN热分解的主要气体产物为N2O、NO2、NH3、H2O和N2,气体产物N2O、NO2和NH3的动力学参数的Ea值分别为157.5、158.6、100.0 kJ/mol,从微观角度提出了ADN可能的热分解机理.

  12. Binding of cationic peptides (KX)4K to DPPG bilayers. Increasing the hydrophobicity of the uncharged amino acid X drives formation of membrane bound β-sheets: A DSC and FT-IR study.

    Science.gov (United States)

    Hädicke, André; Blume, Alfred

    2016-06-01

    The binding of cationic peptides of the sequence (KX)4K to lipid vesicles of negatively charged dipalmitoyl-phosphatidylglycerol (DPPG) was investigated by differential scanning calorimetry (DSC) and temperature dependent Fourier-transformed infrared (FT-IR) spectroscopy. The hydrophobicity of the uncharged amino acid X was changed from G (glycine) over A (alanine), Abu (α-aminobutyric acid), V (valine) to L (leucine). The binding of the peptides caused an increase of the phase transition temperature (Tm) of DPPG by up to 20°C. The shift depended on the charge ratio and on the hydrophobicity of the amino acid X. Unexpectedly, the upward shift of Tm increased with increasing hydrophobicity of X. FT-IR spectroscopy showed a shift of the CH2 stretching vibrations of DPPG to lower frequency, particularly for bilayers in the liquid-crystalline phase, indicating an ordering of the hydrocarbon chains when the peptides were bound. Changes in the lipid C=O vibrational band indicated a dehydration of the lipid headgroup region after peptide binding. (KG)4K was bound in an unordered structure at all temperatures. All other peptides formed intermolecular antiparallel β-sheets, when bound to gel phase DPPG. However, for (KA)4K and (KAbu)4K, the β-sheets converted into an unordered structure above Tm. In contrast, the β-sheet structures of (KV)4K and (KL)4K remained stable even at 80°C when bound to the liquid-crystalline phase of DPPG. Strong aggregation of DPPG vesicles occurred after peptide binding. For the aggregates, we suggest a structure, where aggregated single β-sheets are sandwiched between opposing DPPG bilayers with a dehydrated interfacial region. PMID:26903220

  13. Use of DSC and DMA Techniques to Help Investigate a Material Anomaly for PTFE Used in Processing a Piston Cup for the Urine Processor Assembly (UPA) on International Space Station (ISS)

    Science.gov (United States)

    Wingard, Doug

    2010-01-01

    Human urine and flush water are eventually converted into drinking water with the Urine Processor Assembly (UPA) aboard the International Space Station (ISS). This conversion is made possible through the Distillation Assembly (DA) of the UPA. One component of the DA is a molded circular piston cup made of virgin polytetrafluoroethylene (PTFE). The piston cup is assembled to a titanium component using eight fasteners and washers. Molded PTFE produced for spare piston cups in the first quarter of 2010 was different in appearance and texture, and softer than material molded for previous cups. For the suspect newer PTFE material, cup fasteners were tightened to only one-half the required torque value, yet the washers embedded almost halfway into the material. The molded PTFE used in the DA piston cup should be Type II, based on AMS 3667D and ASTM D4894 specifications. The properties of molded PTFE are considerably different between Type I and II materials. Engineers working with the DA thought that if Type I PTFE was molded by mistake instead of Type II material, that could have resulted in the anomalous material properties. Typically, the vendor molds flat sheet PTFE from the same material lot used to mold the piston cups, and tensile testing as part of quality control should verify that the PTFE is Type II material. However, for this discrepant lot of material, such tensile data was not available. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) were two of the testing techniques used at the NASA/Marshall Space Flight Center (MSFC) to investigate the anomaly for the PTFE material. Other techniques used on PTFE specimens were: Shore D hardness testing, tensile testing on dog bone specimens and a qualitative estimation of porosity by optical and scanning electron microscopy.

  14. Evaluation of thermal stability of paraffin wax by differential scanning calorimetry; Avaliacao da estabilidade termica de parafina por calorimetria diferencial de varredura

    Energy Technology Data Exchange (ETDEWEB)

    Godinho, K.O.; Silva, A.G.P.; Holanda, J.N.F. [Universidade Estadual do Norte Fluminense (LAMAV/UENF), Campos dos Goytacazes, RJ (Brazil). Grupo de Materiais Ceramicos], Email: holanda@uenf.br

    2010-07-01

    Phase change materials for heat storage are used as passive solar energy storage materials, which can be impregnated into construction materials. In this work the thermal stability (heating/cooling cycle) of the paraffin wax was investigated using differential scanning calorimetry. The latent heat and fusion temperature were determined for the following thermal cycles: 0, 30, 180 and 360. The thermal stability for paraffin wax infiltrated in support of gypsum was also determined. The experimental results showed that the paraffin wax showed good thermal stability in the states pure and infiltrated for up to 360 thermal cycles. (author)

  15. Study on the non-isothermal curing kinetics of a polyfurfuryl alcohol bioresin by DSC using different amounts of catalyst

    DEFF Research Database (Denmark)

    Dominguez Toribio, Juan Carlos; Grivel, Jean-Claude; Madsen, Bo

    2012-01-01

    The curing kinetics of a biomass-based polyfurfuryl alcohol resin with three different amounts of catalyst was studied by DSC non-isothermal measurements using seven heating rates. The change of the activation energy of the curing process was obtained by the isoconversional methods of Kissinger......–Akahira–Sunone, Flynn–Wall–Ozawa and Vyazovkin. The latter method provided maximum values of the activation energy of about 115, 95 and 80 kJ mol−1 before the gelation point for 2%, 4%, and 6% (w/w) amounts of catalyst, respectively. Based on a purely kinetic criterion, the most suitable amount of catalyst is assessed...... a valuable contribution to the design of improved cure cycles for manufacturing of composite materials with a polyfurfuryl alcohol matrix....

  16. Measurement of glass transition temperature by mechanical (DMTA), thermal (DSC and MDSC), water diffusion and density methods: A comparison study

    Science.gov (United States)

    Rahman, Mohammad Shafiur; Al-Marhubi, Insaaf Mohd; Al-Mahrouqi, Abdullah

    2007-06-01

    Glass transition measured by DMTA from the change in slope in storage modulus was 55 °C, which was 10.5 °C lower than the value measured by tan δ peak. Initial glass transition measured by DSC, increased exponentially and reached a constant value of 55 °C at or higher heating rate of 30 °C/min. Transition temperature, measured by MDSC, remained constant up to heating rate 15 °C/min and then decreased. The glass transition values determined from reversible heat flow was 60 °C. The break in diffusivity and density (i.e. volume) was observed at 50 °C below the glass transition temperature measured by thermal and mechanical methods.

  17. Determination of the melting temperature, heat of fusion, and purity analysis of different samples of zidovudine (AZT using DSC

    Directory of Open Access Journals (Sweden)

    Adriano Antunes Souza Araújo

    2010-03-01

    Full Text Available The determination of chemical purity, melting range, and variation of enthalpy in the process of characterizing medicines is one of the principal requirements evaluated in quality control of the pharmaceutical industry. In this study, the method of purity determination using DSC was outlined, as well as the application of this technique for the evaluation of commercial samples of zidovudine (AZT (raw material supplied by different laboratories. To this end, samples from six different laboratories (A, B, C, D, E, and F and the standard reference (R from the United States Pharmacopeia (USP were analyzed. The DSC curves were obtained in the temperature range of 25 to 200 ºC under the dynamic atmosphere of N2 (50 mL min-1, heating rate of β=2 ºC min-1, using an Al capsule containing approximately 2 mg of sample material. The results demonstrated that the standard reference presented a proportion of 99.83% whereas the AZT samples presented a variation ranging from 97.59 to 99.54%. In addition, the standard reference was found to present a temperature of onset of melting point of 122.80 °C. Regarding the samples of active agents provided by the different laboratories, a variation ranging from 118.70 to 122.87 °C was measured. In terms of ΔHm, the samples presented an average value of 31.12 kJ mol-1.A determinação da pureza química, a faixa de fusão e a variação de entalpia envolvida no processo de caracterização de fármacos é um dos principais requisitos avaliados no controle de qualidade em indústrias farmacêuticas. Neste trabalho é feita uma breve abordagem sobre o método de determinação de pureza utilizando DSC, assim como a aplicação desta técnica para avaliação de amostras comerciais de zidovudina (AZT (matéria-prima fornecida por diferentes laboratórios. Para tal, foram analisadas amostras de seis diferentes laboratórios (A,B,C,D,E e F e a substância química de referência (R da United States Pharmacopeia (USP. As

  18. Analysis of Siderite Thermal Decomposition by Differential Scanning Calorimetry

    Science.gov (United States)

    Bell, M. S.; Lin, I.-C.; McKay, D. S.

    2000-01-01

    Characterization of carbonate devolitilization has important implications for atmospheric interactions and climatic effects related to large meteorite impacts in platform sediments. On a smaller scale, meteorites contain carbonates which have witnessed shock metamorphic events and may record pressure/temperature histories of impact(s). ALH84001 meteorite contains zoned Ca-Mg-Fe-carbonates which formed on Mars. Magnetite crystals are found in the rims and cores of these carbonates and some are associated with void spaces leading to the suggestion by Brearley et al. that the crystals were produced by thermal decomposition of the carbonate at high temperature, possibly by incipient shock melting or devolitilization. Golden et al. recently synthesized spherical Mg-Fe-Ca-carbonates from solution under mild hydrothermal conditions that have similar carbonate compositional zoning to those of ALH84001. They have shown experimental evidence that the carbonate-sulfide-magnetite assemblage in ALH84001 can result from a multistep inorganic process involving heating possibly due to shock events. Experimental shock studies on calcium carbonate prove its stability to approx. 60 GPa, well in excess of the approx. 45 GPa peak pressures indicated by other shock features in ALH84001. In addition, Raman spectroscopy of carbonate globules in ALH84001 indicates no presence of CaO and MgO. Such oxide phases should be found associated with the magnetites in voids if these magnetites are high temperature shock products, the voids resulting from devolitilization of CO2 from calcium or magnesium carbonate. However, if the starting material was siderite (FeCO3), thermal breakdown of the ALH84001 carbonate at 470 C would produce iron oxide + CO2. As no documentation of shock effects in siderite exists, we have begun shock experiments to determine whether or not magnetite is produced by the decomposition of siderite within the < 45GPa pressure window and by the resultant thermal pulse to approx

  19. Energy loss of particles in dense matter - calorimetry

    International Nuclear Information System (INIS)

    In the last decade, a class of detectors gradually have become more and more important in experimental particle physics. They are called calorimeters, or total absorption detectors. Basically a calorimeter is a block of matter, in which the particle to be measured interacts, and deposits all its energy in the form of a shower of decreasingly lower-energy particles. The block is made such that certain (usually small and hopefully constant) fraction of the initial particle energy is transformed in a measurable signal (light, electrical charge). This lecture mainly deals with sampling calorimeters but in section 2 also fully sensitive devices are briefly treated. In this section calorimeters for detecting electromagnetic showers are discussed. The physics processes relevant to em shower development are examined, and the factors that limit the performance of em calorimeters. Section 3 is devoted to readout techniques for sampling calorimeters. In sections 4-7 hadron calorimeters are discussed. The physics processes relevant to hadron shower development, their consequences for the calorimeter signals and the possibility for optimizing the performance of hadron calorimeters are examined. In section 8 an outlook for future development is given. 31 refs.; 48 figs

  20. Isothermal titration calorimetry (ITC) study of surfactants and thermoresponsive poly-oxazolines

    Czech Academy of Sciences Publication Activity Database

    Bogomolova, Anna; Filippov, Sergey K.; Starovoytova, Larisa; Sedláček, Ondřej; Macková, Hana; Hrubý, Martin; Štěpánek, Petr

    Pisa : European Polymer Federation, 2013. P6-13. [European Polymer Congress - EPF 2013. 16.06.2013-21.06.2013, Pisa] Grant ostatní: AV ČR(CZ) M200501201 Institutional support: RVO:61389013 Keywords : isothermal titration calorimetry (ITC) * poly-oxyzolines Subject RIV: CD - Macromolecular Chemistry

  1. Direct absorbed dose to water determination based on water calorimetry in scanning proton beam delivery

    International Nuclear Information System (INIS)

    Purpose: The aim of this manuscript is to describe the direct measurement of absolute absorbed dose to water in a scanned proton radiotherapy beam using a water calorimeter primary standard. Methods: The McGill water calorimeter, which has been validated in photon and electron beams as well as in HDR 192Ir brachytherapy, was used to measure the absorbed dose to water in double scattering and scanning proton irradiations. The measurements were made at the Massachusetts General Hospital proton radiotherapy facility. The correction factors in water calorimetry were numerically calculated and various parameters affecting their magnitude and uncertainty were studied. The absorbed dose to water was compared to that obtained using an Exradin T1 Chamber based on the IAEA TRS-398 protocol. Results: The overall 1-sigma uncertainty on absorbed dose to water amounts to 0.4% and 0.6% in scattered and scanned proton water calorimetry, respectively. This compares to an overall uncertainty of 1.9% for currently accepted IAEA TRS-398 reference absorbed dose measurement protocol. The absorbed dose from water calorimetry agrees with the results from TRS-398 well to within 1-sigma uncertainty. Conclusions: This work demonstrates that a primary absorbed dose standard based on water calorimetry is feasible in scattered and scanned proton beams.

  2. Subsite binding energies of an exo-polygalacturonase using isothermal titration calorimetry

    Science.gov (United States)

    Thermodynamic parameters for binding of a series of galacturonic acid oligomers to an exo-polygalacturonase, RPG16 from Rhizopus oryzae, were determined by isothermal titration calorimetry. Binding of oligomers varying in chain length from two to five galacturonic acid residues is an exothermic proc...

  3. Monolithic junction field-effect transistor charge preamplifier for calorimetry at high luminosity hadron colliders

    International Nuclear Information System (INIS)

    The outstanding noise and radiation hardness characteristics of epitaxial-channel junction field-effect transistors (JFET) suggest that a monolithic preamplifier based upon them may be able to meet the strict specifications for calorimetry at high luminosity colliders. Results obtained so far with a buried layer planar technology, among them an entire monolithic charge-sensitive preamplifier, are described

  4. Thermodynamic profiling of Peptide membrane interactions by isothermal titration calorimetry: a search for pores and micelles

    DEFF Research Database (Denmark)

    Henriksen, Jonas Rosager; Andresen, Thomas Lars

    2011-01-01

    mixed peptide-lipid micelles. We have investigated the mode of action of the antimicrobial peptide mastoparan-X using isothermal titration calorimetry (ITC) and cryo-transmission electron microscopy (cryo-TEM). The results show that mastoparan-X induces a range of structural transitions of POPC/POPG (3...

  5. Isothermal Titration Calorimetry and Macromolecular Visualization for the Interaction of Lysozyme and Its Inhibitors

    Science.gov (United States)

    Wei, Chin-Chuan; Jensen, Drake; Boyle, Tiffany; O'Brien, Leah C.; De Meo, Cristina; Shabestary, Nahid; Eder, Douglas J.

    2015-01-01

    To provide a research-like experience to upper-division undergraduate students in a biochemistry teaching laboratory, isothermal titration calorimetry (ITC) is employed to determine the binding constants of lysozyme and its inhibitors, N-acetyl glucosamine trimer (NAG[subscript 3]) and monomer (NAG). The extremely weak binding of lysozyme/NAG is…

  6. Gamma Polari-Calorimetry with SOI pixels for proposals at Extreme Light Infrastructure (ELI-NP)

    CERN Document Server

    Homma, Kensuke

    2015-01-01

    We introduce the concept of Gamma Polari-Calorimetry (GPC) dedicated for proposals at Extreme Light Infrastructure in the Romanian site (ELI-NP). A simulation study shows that an assembly of thin SOI pixel sensors can satisfy our requirements to GPC.

  7. Student Learning of Thermochemical Concepts in the Context of Solution Calorimetry.

    Science.gov (United States)

    Greenbowe, Thomas J.; Meltzer, David E.

    2003-01-01

    Analyzes student performance on solution calorimetry problems in an introductory university chemistry class. Includes data from written classroom exams for 207 students and an extensive longitudinal interview with a student. Indicates learning difficulties, most of which appear to originate from failure to understand, that net increases and…

  8. Levitation calorimetry. IV - The thermodynamic properties of liquid cobalt and palladium.

    Science.gov (United States)

    Treverton, J. A.; Margrave, J. L.

    1971-01-01

    Some of the thermodynamic properties of liquid cobalt and palladium investigated by means of levitation calorimetry are reported and discussed. The presented data include the specific heats and heats of fusion of the liquid metals, and the emissivities of the liquid metal surfaces.

  9. Simulating SiD Calorimetry: Software Calibration Procedures and Jet Energy Resolution

    OpenAIRE

    Cassell, Ron

    2009-01-01

    Simulated calorimeter performance in the SiD detector is examined. The software calibration procedures are described, as well as the perfect pattern recognition PFA reconstruction. Performance of the SiD calorimeters is summarized with jet energy resolutions from calorimetry only, perfect pattern recognition and the SiD PFA algorithm. Presented at LCWS08[1].

  10. National absorbed dose to water references for radiotherapy medium energy X-rays by water calorimetry

    International Nuclear Information System (INIS)

    LNE-LNHB current references for medium energy X-rays are established in terms of air kerma. Absorbed dose to water, which is the quantity of interest for radiotherapy, is obtained by transfer dosimetric techniques following a methodology described in international protocols. The aim of the thesis is to establish standards in terms of absorbed dose to water in the reference protocol conditions by water calorimetry. The basic principle of water calorimetry is to measure the absorbed dose from the rise in temperature of water under irradiation. A calorimeter was developed to perform measurements at a 2 cm depth in water according to IAEA TRS-398 protocol for medium energy x-rays. Absorbed dose rates to water measured by calorimetry were compared to the values established using protocols based on references in terms of air kerma. A difference lower than 2.1% was reported. Standard uncertainty of water calorimetry being 0.8%, the one associated to the values from protocols being around 3.0%, results are consistent considering the uncertainties. Thanks to these new standards, it will be possible to use IAEA TRS-398 protocol to determine absorbed dose to water: a significant reduction of uncertainties is obtained (divided by 3 by comparison with the application of the IAEA TRS-277 protocol). Currently, none of the counterparts' laboratories own such an instrument allowing direct determination of standards in the reference conditions recommended by the international radiotherapy protocols. (author)

  11. Phase separation in the organic solid state: simultaneous Synchrotron SAXS / DSC studies of unstable n-alkane blends

    International Nuclear Information System (INIS)

    Full text: Blends of normal alkanes form lamellar structures, when quenched from the melt, in which the separation of the individual chains may be controlled by the chain-length difference, molar composition, isotopic substitution and confinement. We have performed simultaneous synchrotron small-angle X-ray scattering and differential scanning calorimetry studies on 2:1 C28H58:C36D74 mixtures as a function of cooling protocol. Their simultaneous collection enables the temperature-dependent nanostructural changes to be correlated with phase transitions. The data are further complemented by small-angle neutron scattering highlighting the separation of the individual chains via isotopic contrast and optical microscopy indicating changes occurring on the macroscopic scale. Copyright (2005) Australian Institute of Physics

  12. Thermodynamic properties of bromine fluorene derivatives: An experimental and computational study

    International Nuclear Information System (INIS)

    Highlights: • Vapour pressures of two bromine derivatives of fluorene were measured. • Combustion energies of two bromine derivatives of fluorene were determined. • Standard molar ΔH, ΔS and ΔG of sublimation and vapourisation were derived. • Standard molar ΔH, ΔS and ΔG of formation in crystal and gas phases were calculated. • Gas phase ΔH of formation was also estimated by quantum chemical calculations. - Abstract: This report presents a comprehensive experimental and computational study of the thermodynamic properties of two bromine fluorene derivatives: 2-bromofluorene and 2,7-dibromofluorene. The standard (p° = 0.1 MPa) molar enthalpies of formation in the crystalline phase of these compounds were derived from the standard molar energies of combustion, in oxygen, at T = 298.15 K, measured by rotating bomb combustion calorimetry. The vapour pressures of the crystalline phase of the two compounds were measured using the Knudsen effusion method and a static method that has also been used to measure the liquid vapour pressures of 2-bromofluorene. From these results the standard molar enthalpies, entropies and Gibbs energies of sublimation of the two compounds studied and of vapourisation of 2-bromofluorene were derived. The enthalpies and temperatures of fusion were determined from DSC experiments. Derived results of standard enthalpies and Gibbs energies of formation, in both gaseous and crystalline phases, were compared with the ones reported in the literature for fluorene. The experimental values of the gas-phase enthalpies of formation of each compound were compared with estimates based on density functional theory calculations using the B3LYP hybrid exchange–correlation energy functional with the 6-311++G(d,p) basis set

  13. Direct measurement of electron beam quality conversion factors using water calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Renaud, James, E-mail: james.renaud@mail.mcgill.ca; Seuntjens, Jan [Medical Physics Unit, McGill University, Montréal, Québec H3G 1A4 (Canada); Sarfehnia, Arman [Medical Physics Unit, McGill University, Montréal, Québec H3G 1A4, Canada and Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5S 3E2 (Canada); Marchant, Kristin [Allan Blair Cancer Centre, Saskatchewan Cancer Agency, Regina, Saskatchewan S4T 7T1, Canada and Department of Oncology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5A1 (Canada); McEwen, Malcolm; Ross, Carl [Ionizing Radiation Standards, National Research Council of Canada, Ottawa, Ontario K1A 0R6 (Canada)

    2015-11-15

    Purpose: In this work, the authors describe an electron sealed water calorimeter (ESWcal) designed to directly measure absorbed dose to water in clinical electron beams and its use to derive electron beam quality conversion factors for two ionization chamber types. Methods: A functioning calorimeter prototype was constructed in-house and used to obtain reproducible measurements in clinical accelerator-based 6, 9, 12, 16, and 20 MeV electron beams. Corrections for the radiation field perturbation due to the presence of the glass calorimeter vessel were calculated using Monte Carlo (MC) simulations. The conductive heat transfer due to dose gradients and nonwater materials was also accounted for using a commercial finite element method software package. Results: The relative combined standard uncertainty on the ESWcal dose was estimated to be 0.50% for the 9–20 MeV beams and 1.00% for the 6 MeV beam, demonstrating that the development of a water calorimeter-based standard for electron beams over such a wide range of clinically relevant energies is feasible. The largest contributor to the uncertainty was the positioning (Type A, 0.10%–0.40%) and its influence on the perturbation correction (Type B, 0.10%–0.60%). As a preliminary validation, measurements performed with the ESWcal in a 6 MV photon beam were directly compared to results derived from the National Research Council of Canada (NRC) photon beam standard water calorimeter. These two independent devices were shown to agree well within the 0.43% combined relative uncertainty of the ESWcal for this beam type and quality. Absorbed dose electron beam quality conversion factors were measured using the ESWcal for the Exradin A12 and PTW Roos ionization chambers. The photon-electron conversion factor, k{sub ecal}, for the A12 was also experimentally determined. Nonstatistically significant differences of up to 0.7% were found when compared to the calculation-based factors listed in the AAPM’s TG-51 protocol

  14. Direct measurement of electron beam quality conversion factors using water calorimetry

    International Nuclear Information System (INIS)

    Purpose: In this work, the authors describe an electron sealed water calorimeter (ESWcal) designed to directly measure absorbed dose to water in clinical electron beams and its use to derive electron beam quality conversion factors for two ionization chamber types. Methods: A functioning calorimeter prototype was constructed in-house and used to obtain reproducible measurements in clinical accelerator-based 6, 9, 12, 16, and 20 MeV electron beams. Corrections for the radiation field perturbation due to the presence of the glass calorimeter vessel were calculated using Monte Carlo (MC) simulations. The conductive heat transfer due to dose gradients and nonwater materials was also accounted for using a commercial finite element method software package. Results: The relative combined standard uncertainty on the ESWcal dose was estimated to be 0.50% for the 9–20 MeV beams and 1.00% for the 6 MeV beam, demonstrating that the development of a water calorimeter-based standard for electron beams over such a wide range of clinically relevant energies is feasible. The largest contributor to the uncertainty was the positioning (Type A, 0.10%–0.40%) and its influence on the perturbation correction (Type B, 0.10%–0.60%). As a preliminary validation, measurements performed with the ESWcal in a 6 MV photon beam were directly compared to results derived from the National Research Council of Canada (NRC) photon beam standard water calorimeter. These two independent devices were shown to agree well within the 0.43% combined relative uncertainty of the ESWcal for this beam type and quality. Absorbed dose electron beam quality conversion factors were measured using the ESWcal for the Exradin A12 and PTW Roos ionization chambers. The photon-electron conversion factor, kecal, for the A12 was also experimentally determined. Nonstatistically significant differences of up to 0.7% were found when compared to the calculation-based factors listed in the AAPM’s TG-51 protocol. General

  15. Enhanced thermal property measurement of a silver zinc battery cell using isothermal calorimetry

    International Nuclear Information System (INIS)

    Highlights: • Design and construction of novel heat flow calorimeter for large battery cell. • Heat flow characterization of silver zinc battery under load. • Thermal efficiency determination of silver zinc battery under load. • Surface map of heat flow of silver zinc battery under load. - Abstract: The push for increased energy density of electrochemical cells highlights the need for novel electrochemical techniques as well as additional characterization methods for these cells in order to meet user needs and safety requirements. To achieve ever increasing energy densities and faster controlled release of that energy, all materials of construction must be constantly evaluated from electrode to casing and everything in-between. Increasing the energy density of the cell improves its utility, but it also increases the waste heat and maximum potential uncontrolled energy release. Design agents and system developers need new ways to monitor and classify the probability and severity of the catastrophic failures as well as the system characteristics during intended operation. To support optimization of these battery cells it is necessary to understand their thermal characteristics at rest as well as under prescribed charge and discharge cycles. One of the many calorimetric tools available to observe and record these characteristics is heat flow calorimetry. Typically, a heat flow calorimeter is operated isothermally and measures the sum heat released or consumed by a sample material inside of a calorimetric measuring cell. For this study an improved calorimetric measuring cell for a modified Hart 6209 precision temperature bath was designed and constructed to measure the heat flow of larger electrochemical cells (18 × 8 × 16 cm). This new calorimetric measuring cell is constructed to allow independent measurements of heat flow among each of the sample’s six sides in contrast to the typical one measurement of the average heat flow. Heat flows from 0.01 to 7

  16. Avaliação por SAXS e DSC das interações entre H2O e Renex-100

    Directory of Open Access Journals (Sweden)

    Daniella Dias Palombino de Campos

    2012-01-01

    Full Text Available The aggregation behavior of the non-ionic surfactant Renex-100 in aqueous solutions and mesophases was evaluated by SAXS in a wide range of concentrations, between 20 and 30 °C. Complementary, water interactions were defined by DSC curves around 0°C. SAXS showed that the system undergoes the following phase transitions, from diluted to concentrated aqueous solutions: 1 isotropic solution of Renex aggregates; 2 hexagonal mesophase; 3 lamellar mesophase; and 4 isotropic solution. DSC analysis indicated the presence of interfacial water above 70wt%, which agreed with the segregation of free water to form the structural mesophases observed by SAXS bellow this concentration.

  17. Dublin South Central (DSC)

    LENUS (Irish Health Repository)

    O'Gorman, Clodagh S M

    2010-12-01

    Children who appear healthy, even if they have one or more recognized cardiovascular risk factors, do not generally have outcomes of cardiovascular or other vascular disease during childhood. Historically, pediatric medicine has not aggressively screened for or treated cardiovascular risk factors in otherwise healthy children. However, studies such as the P-Day Study (Pathobiological Determinants of Atherosclerosis in Youth), and the Bogalusa Heart Study, indicate that healthy children at remarkably young ages can have evidence of significant atherosclerosis. With the increasing prevalence of pediatric obesity, can we expect more health problems related to the consequences of pediatric dyslipidemia, hypertriglyceridemia, and atherosclerosis in the future? For many years, medications have been available and used in adult populations to treat dyslipidemia. In recent years, reports of short-term safety of some of these medications in children have been published. However, none of these studies have detailed long-term follow-up, and therefore none have described potential late side-effects of early cholesterol-lowering therapy, or potential benefits in terms of reduction of or delay in cardiovascular or other vascular end-points. In 2007, the American Heart Association published a scientific statement on the use of cholesterol-lowering therapy in pediatric patients. In this review paper, we discuss some of the current literature on cholesterol-lowering therapy in children, including the statins that are currently available for use in children, and some of the cautions with using these and other cholesterol-lowering medications. A central tenet of this review is that medications are not a substitute for dietary and lifestyle interventions, and that even in children on cholesterol-lowering medications, physicians should take every opportunity to encourage children and their parents to make healthy diet and lifestyle choices.

  18. Comparison of first pass bolus AIFs extracted from sequential 18F-FDG PET and DSC-MRI of mice

    International Nuclear Information System (INIS)

    Accurate kinetic modelling of in vivo physiological function using positron emission tomography (PET) requires determination of the tracer time–activity curve in plasma, known as the arterial input function (AIF). The AIF is usually determined by invasive blood sampling methods, which are prohibitive in murine studies due to low total blood volumes. Extracting AIFs from PET images is also challenging due to large partial volume effects (PVE). We hypothesise that in combined PET with magnetic resonance imaging (PET/MR), a co-injected bolus of MR contrast agent and PET ligand can be tracked using fast MR acquisitions. This protocol would allow extraction of a MR AIF from MR contrast agent concentration–time curves, at higher spatial and temporal resolution than an image-derived PET AIF. A conversion factor could then be applied to the MR AIF for use in PET kinetic analysis. This work has compared AIFs obtained from sequential DSC-MRI and PET with separate injections of gadolinium contrast agent and 18F-FDG respectively to ascertain the technique′s validity. An automated voxel selection algorithm was employed to improve MR AIF reproducibility. We found that MR and PET AIFs displayed similar character in the first pass, confirmed by gamma variate fits (p<0.02). MR AIFs displayed reduced PVE compared to PET AIFs, indicating their potential use in PET/MR studies

  19. Evaluation of crystallization kinetics of poly (ether-ketone-ketone and poly (ether-ether-ketone by DSC

    Directory of Open Access Journals (Sweden)

    Gibran da Cunha Vasconcelos

    2010-08-01

    Full Text Available The poly (aryl ether ketones are used as matrices in advanced composites with high performance due to its high thermal stability, excellent environmental performance and superior mechanical properties. Most of the physical, mechanical and thermodynamic properties of semi-crystalline polymers depend on the degree of crystallinity and morphology of the crystalline regions. Thus, a study on the crystallization process promotes a good prediction of how the manufacturing parameters affect the developed structure, and the properties of the final product. The objective of this work was to evaluate the thermoplastics polymers PEKK e PEEK by DSC, aiming to obtain the relationship between kinetics, content, nucleation and geometry of the crystalline phases, according to the parameters of the Avrami and Kissinger models. The analysis of the Avrami exponents obtained for the studied polymers indicates that both showed the formation of crystalline phases with heterogeneous nucleation and growth geometry of the type sticks or discs, depending on the cooling conditions. It was also found that the PEEK has a higher crystallinity than PEKK.

  20. Polymer blends based on PEO and starch: Miscibility and spherulite growth rate evaluated through DSC and optical microscopy

    International Nuclear Information System (INIS)

    The miscibility and PEO spherulite growth rate in PEO/starch blends (starch from cassava) were evaluated using the depression in the melting point (by DSC) and optical polarized microscope, respectively, and compared to pure PEO. The PEO/starch blend ratio changed from 100/0 to 60/40 (weight/weight). The starch induces changes in PEO crystallization on PEO/starch blends but the crystallization rates do not change linearly to the blend ratio. For 90/10, 80/20, 70/30, 65/35 and 60/40 ratios, lower values for the equilibrium melting temperature were observed as compared to the pure PEO. The obtained interaction parameter value was - 0.25 by the use of Nishi-Wang equation. The depression in the equilibrium melting temperatures and the negative value for the polymer-polymer interaction parameter suggest that the blends are miscible in the molten state in the range of investigated ratios, except for the 95/05 ratio in which the equilibrium melting temperature increased relative to the pure PEO. The miscibility should be due to the H-bonds among the hydroxyl groups from starch and oxygen atoms of repeat units of PEO

  1. Melting and crystallization of in-situ polymerized cyclic butylene terephthalates with and without organoclay: a modulated DSC study

    Directory of Open Access Journals (Sweden)

    2007-02-01

    Full Text Available The polymerization of cyclic butylene terephthalate oligomers (CBT were studied in presence (in 5 wt.% and absence of an organoclay (Cloisite® 30B by modulated DSC (MDSC. The organoclay containing samples were produced by dry and melt blending, respectively. The first heating, causing the polymerization of the CBT catalyzed by an organotin compound, was followed by cooling prior to the second heating. The MDSC scans covered the temperature interval between 0 and 260°C. The aim of this protocol was to study the crystallization and melting behavior of the resulting polybutylene terephthalate (pCBT and its organoclay modified nanocomposites. It was found that the thermal behaviors of the polymerizing and polymerized CBT (pCBT were strongly affected by the sample preparation. The organoclay suppressed the crystallization of the pCBT produced during the first heating. However, results from the second heating suggest that more perfect crystallites were formed in the organoclay modified pCBT variants. The organoclay also affected the conversion and mean molecular mass of the resulting pCBT which were slightly lower than those of the plain pCBT polymerized under identical conditions.

  2. Comparison of calorimetry and destructive analytical measurement techniques for excess plutonium powders

    International Nuclear Information System (INIS)

    In Dec. 1994, IAEA safeguards were initiated on inventory of Pu- bearing materials, originating from the US nuclear weapons complex, at vault 3 of DOE's Plutonium Finishing Plant at Hanford. Because of the diversity and heterogeneity of the Pu, plant operators have increasingly used calorimetry for accountability measurements. During the recent commencement of IAEA safeguards at vault 3, destructive (electrochemical titration) methods were used to determine Pu concentrations in subsamples of inventory items with widely ranging chemical purities. The Pu concentrations in the subsamples were determined and contribution of heterogeneity to total variability was identified. Measurement results, gathered by PFP and IAEA laboratories, showed total measurement variability for calorimetry to be comparable with or lower than those of sampling and chemical analyses

  3. Correlative assay of uranium with calorimetry, neutron counting, and mass spectrometry data

    International Nuclear Information System (INIS)

    A methodology has been developed for assaying unirradiated enriched uranium that uses calorimetry, passive neutron counting, and historical mass spectrometry data. Calorimetry can be used to measure the thermal power of bulk uranium enriched in the isotope 235U, and neutron counting can be used to determine its spontaneous-fission neutron emission rate. The thermal power and neutron-emission properties of uranium change in a regular way with increasing 235U enrichment that can be quantified using mass spectrometry data. The measured ratio of the thermal power and spontaneous neutron fission rate can be used to determine the 235U enrichment and the total mass of the 234U, 235U, and 238U isotopes

  4. Kinetics of Enzymatic High-Solid Hydrolysis of Lignocellulosic Biomass Studied by Calorimetry

    DEFF Research Database (Denmark)

    Olsen, Søren Nymand; Rasmussen, Erik Lumby; McFarland, K.C.;

    2011-01-01

    Enzymatic hydrolysis of high-solid biomass (>10% w/w dry mass) has become increasingly important as a key step in the production of second-generation bioethanol. To this end, development of quantitative real-time assays is desirable both for empirical optimization and for detailed kinetic analysis....... In the current work, we have investigated the application of isothermal calorimetry to study the kinetics of enzymatic hydrolysis of two substrates (pretreated corn stover and Avicel) at high-solid contents (up to 29% w/w). It was found that the calorimetric heat flow provided a true measure of the...... hydrolysis rate with a detection limit of about 500 pmol glucose s−1. Hence, calorimetry is shown to be a highly sensitive real-time method, applicable for high solids, and independent on the complexity of the substrate. Dose–response experiments with a typical cellulase cocktail enabled a multidimensional...

  5. Application of isothermal calorimetry and uv spectroscopy for stability monitoring of pentaerythritol tetranitrate

    International Nuclear Information System (INIS)

    Thermal stabilities for a series of pentaerythritol-tetranitrate (PETN) samples with variable surf ace areas were monitored by isothermal calorimetry and UV spectroscopy over the temperature range of 363 to 408 K. Isothermal induction times measured with constant volume calorimetry under an air atmosphere and No evolution rates monitored by UV absorbance at 213 nm under vacuum correlated with the PETN surface area at temperatures equal to or exceeding 383 K. Rate data measured at 383 K are in accord with predictions based on detailed kinetic modeling. Below 383 K, NO evolution data suggested that additional geometric factors may be significant in controlling PETN stability. Mechanisms for influencing surface area upon the rate-determining step are addressed

  6. Radiation damage study for silicon calorimetry: Summary of first year's activity

    International Nuclear Information System (INIS)

    In the first contract year of this activity at Carnegie-Mellon we have had two major objectives. These were to devise and test a non-intrusive means to measure the energy and spatial profiles of the neutrons generated in a hadronic cascade at high energy; and to study the calibration systematics of silicon diode detectors as a prelude to their evaluation for SSC calorimetry. These objectives have been carried out, as are described in this paper. In addition we have recoded the ORNL detector simulation program HETC to operate on a VAX and are working on the conversion of the low energy neutron transport program MORSE. These programs are used heavily at Oak Ridge (Gabriel and coworkers) for cascade studies. For silicon calorimetry one wants to have more control over the energy deposition routines, especially in MORSE. Unfortunately, MORSE is heavily-laden with machine code, and its conversion is going slowly. 11 refs., 5 figs

  7. Picosecond calorimetry

    DEFF Research Database (Denmark)

    Georgiou, Panayiotis; Vincent, Jonathan; Andersson, Magnus;

    2006-01-01

    Liquid phase time-resolved x-ray diffraction with 100 ps resolution has recently emerged as a powerful technique for probing the structural dynamics of transient photochemical species in solution. It is intrinsic to the method, however, that a structural signal is observed not only from the photo...

  8. Absolute dosimetry on a dynamically scanned sample for synchrotron radiotherapy using graphite calorimetry and ionization chambers.

    Science.gov (United States)

    Lye, J E; Harty, P D; Butler, D J; Crosbie, J C; Livingstone, J; Poole, C M; Ramanathan, G; Wright, T; Stevenson, A W

    2016-06-01

    The absolute dose delivered to a dynamically scanned sample in the Imaging and Medical Beamline (IMBL) on the Australian Synchrotron was measured with a graphite calorimeter anticipated to be established as a primary standard for synchrotron dosimetry. The calorimetry was compared to measurements using a free-air chamber (FAC), a PTW 31 014 Pinpoint ionization chamber, and a PTW 34 001 Roos ionization chamber. The IMBL beam height is limited to approximately 2 mm. To produce clinically useful beams of a few centimetres the beam must be scanned in the vertical direction. In practice it is the patient/detector that is scanned and the scanning velocity defines the dose that is delivered. The calorimeter, FAC, and Roos chamber measure the dose area product which is then converted to central axis dose with the scanned beam area derived from Monte Carlo (MC) simulations and film measurements. The Pinpoint chamber measures the central axis dose directly and does not require beam area measurements. The calorimeter and FAC measure dose from first principles. The calorimetry requires conversion of the measured absorbed dose to graphite to absorbed dose to water using MC calculations with the EGSnrc code. Air kerma measurements from the free air chamber were converted to absorbed dose to water using the AAPM TG-61 protocol. The two ionization chambers are secondary standards requiring calibration with kilovoltage x-ray tubes. The Roos and Pinpoint chambers were calibrated against the Australian primary standard for air kerma at the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA). Agreement of order 2% or better was obtained between the calorimetry and ionization chambers. The FAC measured a dose 3-5% higher than the calorimetry, within the stated uncertainties. PMID:27192396

  9. Study of moisture structurization and binding form changes in pectin gels by differential scanning calorimetry

    OpenAIRE

    Крапивницька, Ірина Олексіївна; Потапов, Володимир Олексійович; Гурський, Петро Васильович; Перцевой, Федір Всеволодович

    2015-01-01

    During thermal cycling, changes in the structure and moisture-holding capacity of the samples of pectin gels with different formulations were investigated using differential scanning calorimetry by their cyclic heating and freezing.The fact that pectin gels are used for a wide variety of foods and semi-finished products, subjected to heat treatment in a wide temperature range from positive to negative was also taken into account during thermal cycling.The influence of the main formula compone...

  10. Monitoring of an RNA Multistep Folding Pathway by Isothermal Titration Calorimetry

    OpenAIRE

    Reymond, Cédric; Bisaillon, Martin; Perreault, Jean-Pierre

    2008-01-01

    Isothermal titration calorimetry was used to monitor the energetic landscape of a catalytic RNA, specifically that of the hepatitis delta virus ribozyme. Using mutants that isolated various tertiary interactions, the thermodynamic parameters of several ribozyme-substrate intermediates were determined. The results shed light on the impact of several tertiary interactions on the global structure of the ribozyme. In addition, the data indicate that the formation of the P1.1 pseudoknot is the lim...

  11. Determination of the aggregation number for micelles by isothermal titration calorimetry

    DEFF Research Database (Denmark)

    Olesen, Niels Erik; Holm, Rene; Westh, Peter

    2014-01-01

    Isothermal titration calorimetry (ITC) has previously been applied to estimate the aggregation number (n), Gibbs free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) of micellization. However, some difficulties of micelle characterization by ITC still remain; most micelles have aggregation numbers...... insight into optimal design of titration protocols for micelle characterization. By applying the new method, the aggregation number of sodium dodecyl sulphate and glycochenodeoxycholate was determined at concentrations around their critical micelle concentration (CMC)...

  12. Indirerect calorimetry in nowborn and post-weaning mice: methodological aspects

    Czech Academy of Sciences Publication Activity Database

    Janovská, Petra; Matějčková, Eva; Kůs, Vladimír; Kopecký, Jan

    Budapest, 2007. s. 27-27. [Pre-congress satellite meeting of the European congress on obesity /15./. 20.04.-21.04.2007, Budapest] R&D Projects: GA MŠk(CZ) 1M0520; GA ČR(CZ) GA303/05/2580 Institutional research plan: CEZ:AV0Z50110509 Keywords : energy expenditure * indirect calorimetry * early postnatal development Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition

  13. Irreversible Denaturation of Maltodextrin Glucosidase Studied by Differential Scanning Calorimetry, Circular Dichroism, and Turbidity Measurements

    OpenAIRE

    Goyal, Megha; Chaudhuri, Tapan K; Kuwajima, Kunihiro

    2014-01-01

    Thermal denaturation of Escherichia coli maltodextrin glucosidase was studied by differential scanning calorimetry, circular dichroism (230 nm), and UV-absorption measurements (340 nm), which were respectively used to monitor heat absorption, conformational unfolding, and the production of solution turbidity. The denaturation was irreversible, and the thermal transition recorded at scan rates of 0.5–1.5 K/min was significantly scan-rate dependent, indicating that the thermal denaturation was ...

  14. Characterization of photomultiplier tubes in a novel secondary ionization mode for Secondary Emission Ionization Calorimetry

    CERN Document Server

    Tiras, E; Ogul, H; Southwick, D; Bilki, B; Nachtman, J; Onel, Y

    2016-01-01

    Hamamatsu single anode R7761 and multi-anode R5900-00-M16 Photomultiplier Tubes have been characterized for use in Secondary Emission Ionization Calorimetry study, that is a novel techique to measure the electromagnetic shower particles in extreme radiation environment. There are different SE modes used in the tests, developed from conventional PMT mode. Here, the technical design of secondary emission modules and characterization measurements of both SE modes and the PMT mode are reported.

  15. Absolute dosimetry on a dynamically scanned sample for synchrotron radiotherapy using graphite calorimetry and ionization chambers

    Science.gov (United States)

    Lye, J. E.; Harty, P. D.; Butler, D. J.; Crosbie, J. C.; Livingstone, J.; Poole, C. M.; Ramanathan, G.; Wright, T.; Stevenson, A. W.

    2016-06-01

    The absolute dose delivered to a dynamically scanned sample in the Imaging and Medical Beamline (IMBL) on the Australian Synchrotron was measured with a graphite calorimeter anticipated to be established as a primary standard for synchrotron dosimetry. The calorimetry was compared to measurements using a free-air chamber (FAC), a PTW 31 014 Pinpoint ionization chamber, and a PTW 34 001 Roos ionization chamber. The IMBL beam height is limited to approximately 2 mm. To produce clinically useful beams of a few centimetres the beam must be scanned in the vertical direction. In practice it is the patient/detector that is scanned and the scanning velocity defines the dose that is delivered. The calorimeter, FAC, and Roos chamber measure the dose area product which is then converted to central axis dose with the scanned beam area derived from Monte Carlo (MC) simulations and film measurements. The Pinpoint chamber measures the central axis dose directly and does not require beam area measurements. The calorimeter and FAC measure dose from first principles. The calorimetry requires conversion of the measured absorbed dose to graphite to absorbed dose to water using MC calculations with the EGSnrc code. Air kerma measurements from the free air chamber were converted to absorbed dose to water using the AAPM TG-61 protocol. The two ionization chambers are secondary standards requiring calibration with kilovoltage x-ray tubes. The Roos and Pinpoint chambers were calibrated against the Australian primary standard for air kerma at the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA). Agreement of order 2% or better was obtained between the calorimetry and ionization chambers. The FAC measured a dose 3–5% higher than the calorimetry, within the stated uncertainties.

  16. A bipolar monolithic preamplifier for high-capacitance SSC [Superconducting Super Collider] silicon calorimetry

    International Nuclear Information System (INIS)

    This paper describes a preamplifier designed and fabricated specifically to address the requirements of silicon calorimetry for the Superconducting Super Collider (SSC). The topology and its features are discussed in addition to the design methodology employed. The simulated and measured results for noise, power consumption, and speed are presented. Simulated an measured data for radiation damage effects as well as data for post-damage annealing are also presented. 8 refs., 7 figs., 2 tabs

  17. Immersion Calorimetry for the Characterization of PD Catalysts Supported on Activated Carbon

    OpenAIRE

    Liliana Giraldo; Juan Carlos Moreno-Piraján

    2009-01-01

    Activated carbons obtained from coconut peel were oxidized using hydrogen peroxide. Superficial characteristics of these carbons were determined through N2 and CO2 isotherms and functional groups were characterized by TPD. Finally, the microcalorimetry technique was used in order to obtain the immersion enthalpies in diverse liquids and established the relation between them and the results obtained by the other characterization techniques. The results suggested that the immersion calorimetry ...

  18. An indirect calorimetry system for ventilator dependent very low birthweight infants.

    OpenAIRE

    Matthews, D S; Matthews, J. N.

    1992-01-01

    With neurodevelopmental outcome of very low birthweight (VLBW) infants being adversely affected by inadequate nutrition during the first few weeks of life, there is an urgent need for more specific nutritional data on the sick VLBW ventilator dependent infant. The development of a new mass spectrometry gas analysis indirect calorimetry system which is non-invasive and can operate over several hours or days is described. Technical evaluation of each of the components of the system indicates a ...

  19. Hydration water and peptide dynamics--two sides of a coin. A neutron scattering and adiabatic calorimetry study at low hydration and cryogenic temperatures.

    Science.gov (United States)

    Bastos, Margarida; Alves, Nuno; Maia, Sílvia; Gomes, Paula; Inaba, Akira; Miyazaki, Yuji; Zanotti, Jean-Marc

    2013-10-21

    In the present work we bridge neutron scattering and calorimetry in the study of a low-hydration sample of a 15-residue hybrid peptide from cecropin and mellitin CA(1-7)M(2-9) of proven antimicrobial activity. Quasielastic and low-frequency inelastic neutron spectra were measured at defined hydration levels - a nominally 'dry' sample (specific residual hydration h = 0.060 g/g), a H2O-hydrated (h = 0.49) and a D2O-hydrated one (h = 0.51). Averaged mean square proton mobilities were derived over a large temperature range (50-300 K) and the vibrational density of states (VDOS) were evaluated for the hydrated samples. The heat capacity of the H2O-hydrated CA(1-7)M(2-9) peptide was measured by adiabatic calorimetry in the temperature range 5-300 K, for different hydration levels. The glass transition and water crystallization temperatures were derived in each case. The existence of different types of water was inferred and their amounts calculated. The heat capacities as obtained from direct calorimetric measurements were compared to the values derived from the neutron spectroscopy by way of integrating appropriately normalized VDOS functions. While there is remarkable agreement with respect to both temperature dependence and glass transition temperatures, the results also show that the VDOS derived part represents only a fraction of the total heat capacity obtained from calorimetry. Finally our results indicate that both hydration water and the peptide are involved in the experimentally observed transitions. PMID:23986181

  20. Estimation of Critical Rate of Temperature Rise for Thermal Explosion of First Order Autocatalytic Decomposition Reaction Systems by Using Non-isothermal DSC

    Institute of Scientific and Technical Information of China (English)

    GUO Peng-jiang; LU Gui-e; JIANG Ji-you; HU Rong-zu; ZHANG Hai; XIA Zhi-ming; SONG Ji-rong; GAO Sheng-li; NING Bin-ke; SHI Qi-zhen; LIU Rong

    2004-01-01

    A method of estimating the critical rate of temperature rise for the thermal explosion of first order autocatalytic decomposition reaction systems by using non-isothermal DSC is presented. The information was obtained on the increasing rate of temperature for the first order autocatalytic decomposition of nitrocellulose containing 13.86% nitrogen converting into the thermal explosion.

  1. Hydrocarbons adsorption on metal trimesate MOFs: Inverse gas chromatography and immersion calorimetry studies

    Energy Technology Data Exchange (ETDEWEB)

    Gutiérrez, Inés; Díaz, Eva; Vega, Aurelio [Department of Chemical and Environmental Engineering, University of Oviedo, Faculty of Chemistry, Julián Clavería s/n, 33006 Oviedo (Spain); Ordóñez, Salvador, E-mail: sordonez@uniovi.es [Department of Chemical and Environmental Engineering, University of Oviedo, Faculty of Chemistry, Julián Clavería s/n, 33006 Oviedo (Spain); Guerrero-Ruiz, Antonio [Department of Inorganic and technical Chemistry, UNED, 28040 Madrid (Spain); Castillejos-López, Eva; Rodríguez-Ramos, Inmaculada [Instituto de Catálisis y Petroleoquímica, CSIC, Madrid (Spain)

    2015-02-20

    Highlights: • Inverse gas chromatography and immersion calorimetry were compared on two MOFs. • Adsorption of seven carbon atoms adsorbates on Cu{sub 3}(BTC){sub 2} and Fe(BTC) was performed. • Size and polarizability of adsorbates are decisive in the strength of adsorption. • Dispersive interaction of surface free energy depends on the surface area. • I{sup sp} is influenced by the chemistry of adsorbates and morphology of the adsorbents. - Abstract: Two commercial metal-organic frameworks, Cu{sub 3}(BTC){sub 2} and Fe(BTC), have been selected to compare the adsorption parameters obtained on these materials by two different techniques: immersion calorimetry and inverse gas chromatography (IGC), in order to find a relationship between thermodynamic parameters obtained by so different techniques. From comparison between the enthalpy of adsorption obtained from IGC and the enthalpy of immersion, three molecules of the same number of carbon atoms have been selected: n-heptane, methylcyclohexane and toluene. Both by IGC and immersion calorimetry, the interaction is stronger in Fe(BTC), being the aromaticity of TOL determinant in the strength of the interaction. However, splitting of the enthalpy of adsorption into the dispersive and specific components allows to deduce that both parameters are more important on the Cu{sub 3}(BTC){sub 2}, due to the higher available surface area in the case of the dispersive interaction; and for the specific interaction, due to the high potential of interaction into the micropores.

  2. Hydrocarbons adsorption on metal trimesate MOFs: Inverse gas chromatography and immersion calorimetry studies

    International Nuclear Information System (INIS)

    Highlights: • Inverse gas chromatography and immersion calorimetry were compared on two MOFs. • Adsorption of seven carbon atoms adsorbates on Cu3(BTC)2 and Fe(BTC) was performed. • Size and polarizability of adsorbates are decisive in the strength of adsorption. • Dispersive interaction of surface free energy depends on the surface area. • Isp is influenced by the chemistry of adsorbates and morphology of the adsorbents. - Abstract: Two commercial metal-organic frameworks, Cu3(BTC)2 and Fe(BTC), have been selected to compare the adsorption parameters obtained on these materials by two different techniques: immersion calorimetry and inverse gas chromatography (IGC), in order to find a relationship between thermodynamic parameters obtained by so different techniques. From comparison between the enthalpy of adsorption obtained from IGC and the enthalpy of immersion, three molecules of the same number of carbon atoms have been selected: n-heptane, methylcyclohexane and toluene. Both by IGC and immersion calorimetry, the interaction is stronger in Fe(BTC), being the aromaticity of TOL determinant in the strength of the interaction. However, splitting of the enthalpy of adsorption into the dispersive and specific components allows to deduce that both parameters are more important on the Cu3(BTC)2, due to the higher available surface area in the case of the dispersive interaction; and for the specific interaction, due to the high potential of interaction into the micropores

  3. Analysis of light particles correlation selected by neutron calorimetry in the reaction 208 Pb+93 Nb at 29 MeV/u

    International Nuclear Information System (INIS)

    This work deals with the analysis of light particles correlation selected by neutrons calorimetry in the reaction : 208 Pb+93 Nb at 29 MeV/u. In the first part are described the interest of correlation functions, the proton-proton correlation function study, the classical model developed for describing the correlations of two light particles emitted by a nucleus in thermal equilibrium, the quantum model and some notions about exclusive sources and measures. The second part is a description of the experience : 208 Pb+93 Nb at 29 MeV/u. The analysis of experimental data and of experimental correlation functions are given respectively in the third and the fourth parts. (O.L.). 38 refs., 82 figs., 11 tabs

  4. Biophysical characterization of the honeybee DSC1 orthologue reveals a novel voltage-dependent Ca2+ channel subfamily: CaV4.

    Science.gov (United States)

    Gosselin-Badaroudine, Pascal; Moreau, Adrien; Simard, Louis; Cens, Thierry; Rousset, Matthieu; Collet, Claude; Charnet, Pierre; Chahine, Mohamed

    2016-08-01

    Bilaterian voltage-gated Na(+) channels (NaV) evolved from voltage-gated Ca(2+) channels (CaV). The Drosophila melanogaster Na(+) channel 1 (DSC1), which features a D-E-E-A selectivity filter sequence that is intermediate between CaV and NaV channels, is evidence of this evolution. Phylogenetic analysis has classified DSC1 as a Ca(2+)-permeable Na(+) channel belonging to the NaV2 family because of its sequence similarity with NaV channels. This is despite insect NaV2 channels (DSC1 and its orthologue in Blatella germanica, BSC1) being more permeable to Ca(2+) than Na(+) In this study, we report the cloning and molecular characterization of the honeybee (Apis mellifera) DSC1 orthologue. We reveal several sequence variations caused by alternative splicing, RNA editing, and genomic variations. Using the Xenopus oocyte heterologous expression system and the two-microelectrode voltage-clamp technique, we find that the channel exhibits slow activation and inactivation kinetics, insensitivity to tetrodotoxin, and block by Cd(2+) and Zn(2+) These characteristics are reminiscent of CaV channels. We also show a strong selectivity for Ca(2+) and Ba(2+) ions, marginal permeability to Li(+), and impermeability to Mg(2+) and Na(+) ions. Based on current ion channel nomenclature, the D-E-E-A selectivity filter, and the properties we have uncovered, we propose that DSC1 homologues should be classified as CaV4 rather than NaV2. Indeed, channels that contain the D-E-E-A selectivity sequence are likely to feature the same properties as the honeybee's channel, namely slow activation and inactivation kinetics and strong selectivity for Ca(2+) ions. PMID:27432995

  5. Standard enthalpies of formation of some carbides, silicides, germanides and borides of holmium by high temperature direct synthesis calorimetry

    International Nuclear Information System (INIS)

    The standard enthalpies of formation for some holmium alloys in the binary systems Ho-X (where X=C, Si, Ge, B) have been determined by direct synthesis calorimetry at 1473±2 K. The following values of ΔHof(298 K) kJ (mol of atoms)-1 are reported: HoC2=-28.6±1.2; HoSi=-80.9±2.2; HoSi2=-57.8±2.4; Ho5Si3=-74.6±2.1; Ho5≥3=-91.8±1.7; HoB2=-27.9±1.5. The results are compared with some earlier experimental values derived from mass spectrometric measurements, with available calorimetric data for the corresponding compounds of some of the early lanthanide elements, and with predicted values from the semi-empirical model of Miedema and co-workers. We also test the possible correlation between the enthalpies of formation and the relative molar volumes of the compounds as suggested by Gschneidner. (orig.)

  6. Simultaneous Characterization for the Organic Additive Burnout of Aqueous Tape Casting Aluminum Nitride by Thermogravimetry-Differential Scanning Calorimetry-Mass Spectrometry%水基AlN流延膜有机添加剂排胶过程的热重-差示扫描热量-质谱研究

    Institute of Scientific and Technical Information of China (English)

    于惠梅; 雒晓军; 陆昌伟; 奚同庚; 罗澜

    2004-01-01

    In this work, through the comparison analysis with the results of the thermogravimetry-differential scanning calorimetry-mass spectrometry (TG-DSC-MS) coupling techniques for the three organic additive and aqueous tape casting aluminum nitride in air and nitrogen atmosphere, it can be found that the plasticity glycerol was almost burnout before 350℃ in two atmosphere; the binder PVA124 was almost burnout before 600℃ in air, there was little left in nitrogen; The mass losses of the dispersant DP270 in air and nitrogen atmosphere were about 73.32% and 65.51% before 600℃ ; The mass losses of the aqueous tape casting aluminum nitride in air (14.08%) were higher that in nitrogen (10.75%) before 600℃. It can be concluded that the organic additive burnout of the aqueous tape casting aluminum nitride in air atmosohere was better than in nitrogen atmosphere.

  7. New experimental heat capacity and enthalpy of formation of lithium cobalt oxide

    International Nuclear Information System (INIS)

    Highlights: • LiCoO2 heat capacity was measured in the temperature range (160 to 953) K using DSC. • Continuous/discontinuous methods were applied on different types of calorimeters. • Enthalpy increment of LiCoO2 was determined using drop calorimetry at T = 974 K. • Enthalpies of formation were evaluated from oxide melt drop solution calorimetry. - Abstract: The heat capacity of LiCoO2 (O3-phase), constituent material in cathodes for lithium-ion batteries, was measured using two differential scanning calorimeters over the temperature range from (160 to 953) K (continuous method). As an alternative, the discontinuous method was employed over the temperature range from (493 to 693) K using a third calorimeter. Based on the results obtained, the enthalpy increment of LiCoO2 was derived from T = 298.15 K up to 974.15 K. Very good agreement was obtained between the derived enthalpy increment and our independent measurements of enthalpy increment using transposed temperature drop calorimetry at 974.15 K. In addition, values of the enthalpy of formation of LiCoO2 from the constituent oxides and elements were assessed based on measurements of enthalpy of dissolution using high temperature oxide melt drop solution calorimetry. The high temperature values obtained by these measurements are key input data in safety analysis and optimisation of the battery management systems which accounts for possible thermal runaway events

  8. Investigation of lipid membrane macro- and micro-structure using calorimetry and computer simulation: structural and functional relationships

    DEFF Research Database (Denmark)

    Jørgensen, Kent; Mouritsen, Ole G.

    1999-01-01

    The lipid bilayer part of biological membranes is a complex lipid mixture displaying cooperative phenomena. By means of differential scanning calorimetry and computer simulation techniques, the equilibrium and non-equilibrium properties of the large assembly of mutually interacting amphiphilic...

  9. Application of In-Line Mid-Infrared (MIR) Spectroscopy Coupled with Calorimetry for the Determination of the Molar Enthalpy of Reaction between Ammonium Chloride and Sodium Nitrite.

    Science.gov (United States)

    Kartnaller, Vinicius; Mariano, Danielly C O; Cajaiba, João

    2016-03-01

    The reaction between ammonium chloride and sodium nitrite has been known for its application as a source of heat because of its large enthalpy of reaction, for which it has been used by the oil industry. There have been no known calorimetric studies for the experimental determination of its molar enthalpy of reaction, which is necessary in order to predict the limits achieved for up-scale applications. Attenuated total reflection Fourier transform infrared spectroscopy (ATR FT-IR) and reaction calorimetry were used to determine this value by using a simple methodology. Both techniques were used concomitantly as a source of information regarding the time-dependent moles converted (Δn) and the amount of exchanged heat (ΔH). The molar enthalpy of reaction was calculated to be -74 ± 4 kcal mol(-1). The percentage between the confidence interval and the calculated value was 5.4%, which shows that the methodology was precise. After the determination of the molar enthalpy of reaction, it was proved that the ATR FT-IR alone was able to be used as a substitute for the reaction calorimetry technique, in which the IR signal is converted to the heat information, presenting as an easier technique for the monitoring of the heat released by this system for future applications. PMID:26798078

  10. Thermochromic transitions of some tetrachlorocuprates of protonated ammines determined by differential scanning calorimetry

    Science.gov (United States)

    Fernández, F.; Fernández, V.; Gutiérrez-Rios, M. a.T.; Sánchez, C.

    1990-11-01

    The enthalpies of the thermochromic phase transitions of the tetrachlorocuprates (II) of a group of protonated ammines (n-propyl (I), iso-propyl (II), n-butyl (III), iso-butyl (IV), octyl (V), lauryl-ammine (VI), pyridine (VII) and piperidine (VIII)) have been determined by DSC. The transition temperatures correlate with the colour change shown by the samples. It is concluded that these transitions are associated with a modification of the CuCl 42- structure to a more square-planar one in some of the compounds (I, II, III, IV, V, VI) and with a deformation to a more tetrahedral one in the other compounds (VII and VIII).

  11. Instability of the CuCl2–NH3BH3 mixture followed by TGA and DSC

    International Nuclear Information System (INIS)

    Graphical abstract: The addition of copper chloride is an efficient approach to destabilize ammonia borane. However, the destabilization is excessive. The mixture CuCl2–NH3BH3 evolves under argon atmosphere and at room temperature. This makes long-term storage of CuCl2–NH3BH3 problematic. Highlights: ► Ammonia borane NH3BH3 (AB) destabilization can be achieved by adding CuCl2. ► The stability of CuCl2–AB when stored under Ar at 20 °C over 6 months was assessed. ► CuCl2–NH3BH3 evolves with time, decomposing at slow kinetics. ► Long-term storage of CuCl2–AB is inconceivable for safety and performances reasons. - Abstract: In the field of ‘hydrogen storage and generation’, ammonia borane NH3BH3 (AB) destabilization can be achieved by adding a metal halide, here copper chloride (CuCl2). Improved dehydrogenation properties can be achieved with a fresh mixture of CuCl2–NH3BH3. Using a systematic approach, we followed the stability of the mixture using thermogravimetric analysis, differential scanning calorimetry and (micro) gas chromatography while it was stored under argon at room temperature over 6 months. The aged samples showed improved dehydrogenation properties compared to pristine AB. However, the performance deteriorated in comparison to the fresh mixture indicating that CuCl2–NH3BH3 evolves over time, decomposing with slow kinetics. This is detrimental in terms of stability during storage, making long-term storage of CuCl2 inconceivable for safety and performance reasons. This is discussed herein

  12. Differential Scanning Calorimetry Investigations on Polyvinylidene Fluoride - Fe3O4 Nanocomposites

    Science.gov (United States)

    Salinas, Samantha; Jones, Robert; Chipara, Dorina M.; Chipara, Mircea

    2015-03-01

    Nanocomposites of polyvinylidene fluoride (PVDF)-magnetite (Fe3O4) with various weight fractions of nanofiller (0%, 0.2 %, 0.6 %, 1.2%, 2.4 %, 5.8 %, 12 %, 23 %, and 30 %) have been obtained via melt mixing by loading PVDF with Fe3O4 particles (average size 75 nm from Nanostructured & Amorphous Materials, Inc). Thermal stability of PVDF-Fe3O4 has been investigated by TGA in nitrogen. The increase of the thermal stability of PVDF due to the loading with Fe3O4 was quantified by the shift of the temperature at which the (mass) degradation rate is maximum as a function of Fe3O4 content. The effect of the nanofiller on the crystallization of PVDF was investigated by isothermal DSC (TA Instruments, Q500). Non isothermal DSC tests, (at various heating rates ranging from 1 to 25 °C/min) have been used to locate the glass, crystallization, and melting temperatures. The dependence of the glass, crystallization, and melting temperatures on the concentration of nanoparticles is reported and analyzed in detail. The data are critically analyzed within the classical Avrami theory.

  13. Aqueous solutions of proline and NaCl studied by differential scanning calorimetry at subzero temperatures

    DEFF Research Database (Denmark)

    Rasmussen, Peter Have; Jørgensen, Bo; Nielsen, Jette

    1997-01-01

    /w) indicating a high water solubility of proline at subzero temperatures. No glass transition was observed within the concentration range 0.9-40.1 wt% (w/w), neither at a low scanning rate of 2.5 degrees C/min nor at a higher scanning rate of 10 degrees C/min. Eutectic crystallization of proline was not...... observed during freezing or melting which shows that proline has the ability to stay in solution at subzero temperatures. Samples containing proline-NaCl-water were also investigated by DSC and it was shown that the solubility of proline is maintained in aqueous salt solutions at temperatures as low as -60...... degrees C. From DSC measurements it was found that the eutectic crystallization of NaCl is prevented by the presence of proline, even when NaCl (initially) is present in molar excess ([NaCl]/[proline] = 2.6). The possible association of these findings with the occurrence of proline accumulation in some...

  14. Performance Test of High Heat Flux Test Facility for the Calorimetry and Beam Control

    International Nuclear Information System (INIS)

    The Korea Heat Load Test facility, KoHLT-EB (Electron Beam) has been operating for the plasma facing components to develop fusion engineering in Korea. The ITER Neutral Beam Duct Liner (NBDL) was fabricated and tested to qualify the thermocouple fixation method for the temperature measurement during a direct collision of the high-power neutral beam during ITER operation. The NBDL is CuCrZr panels, which are actively water cooled using deep drilled channels. To perform the profile test, the assessment for the possibility of an electron beam Gaussian power density profile and the result of absorbed power for that profile before the test start is needed. To assess the possibility of Gaussian profile, for the qualification test of a Gaussian heat load profile, small calorimetry was manufactured to simulate a real heat profile in the neutral beam duct liner, and this calorimetry has two cooling channel with five thermocouples, which is the same as NBDL. Preliminary analyses with ANSYSCFX using a 3D model were performed with the calorimetry model. The heating area was modeled to be 60 mm x 250 mm. The simulated heat flux is 0.5 - 1.2 MW/m''2 at 0.75 kg/sec of the water flow rate. A steady heat flux test was performed to measure the surface heat flux, surface temperature profile. With a thermohydraulic analysis and heat load test, the Gaussian heat profile will be confirmed for this calorimetry and NBDL mockup. The Korean heat load test facility will be used to qualify the specifications of various plasma facing components in fusion devices. To conduct a beam profile test, an assessment of the possibility of electron beam Gaussian power density profile and the results of the absorbed power for that profile before the test starts are needed. To assess the possibility of a Gaussian profile, for the qualification test of the Gaussian heat load profile, a calorimeter mockup and large Cu module were manufactured to simulate real heat. For this high-heat flux test

  15. Development of Temperature Measurements and Calorimetry for the Neutral Beam Test Stand Operation at KAERI

    International Nuclear Information System (INIS)

    Operation of the Neutral Beam Test Stand(NB-TS) at Korea Atomic Energy Research Institute(KAERI) now reaches to 80 kV-20A for about 10 seconds. Experiments with this kind of enormous power and energy necessarily entail many temperature measurements at various locations of the system, and most of the beam line components require to be monitored of their temperatures. We have been implementing temperature measurement utilizing K-Type and T-Type thermocouples(TCs) and a Pt-100 resistance temperature detector for the instrumentation and control and for establishing calorimetry during the operation of the NB-TS facility

  16. Test in a beam of large-area Micromegas chambers for sampling calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Adloff, C.; Chefdeville, M., E-mail: chefdevi@lapp.in2p3.fr; Dalmaz, A.; Drancourt, C.; Gaglione, R.; Geffroy, N.; Jacquemier, J.; Karyotakis, Y.; Koletsou, I.; Peltier, F.; Samarati, J.; Vouters, G.

    2014-11-01

    The application of Micromegas for sampling calorimetry puts specific constraints on the design and performance of this gaseous detector. In particular, uniform and linear response, low noise and stability against high ionisation density deposits are prerequisites for achieving good energy resolution. A Micromegas-based hadronic calorimeter was proposed for an application at a future linear collider experiment and three technologically advanced prototypes of 1×1 m{sup 2} were constructed. Their merits relative to the above-mentioned criteria are discussed on the basis of measurements performed at the CERN SPS test-beam facility.

  17. Isothermal titration calorimetry with micelles: Thermodynamics of inhibitor binding to carnitine palmitoyltransferase 2 membrane protein ☆

    OpenAIRE

    Perspicace, Samantha; Rufer, Arne C.; Thoma, Ralf; Mueller, Francis; Hennig, Michael; Ceccarelli, Simona; Schulz-Gasch, Tanja; Seelig, Joachim

    2013-01-01

    Carnitine palmitoyl transferase 2 (CPT-2) is a key enzyme in the mitochondrial fatty acid metabolism. The active site is comprised of a Y-shaped tunnel with distinct binding sites for the substrate acylcarnitine and the cofactor CoA. We investigated the thermodynamics of binding of four inhibitors directed against either the CoA or the acylcarnitine binding sites using isothermal titration calorimetry (ITC). CPT-2 is a monotopic membrane protein and was solubilized by β-octylglucoside (β-OG) ...

  18. Water flow calorimetry measurements of heat loads for a volume production H- source

    International Nuclear Information System (INIS)

    The design of volume-production H- sources requires the knowledge of heat loads on the source components. The arc and filament heater power input to a 20 cm diameter x 23 cm long source can be 50 kW or higher, practically all of which is absorbed in the cooling water. Water flow calorimetry measurements were made to determine the heat loads on the bucket walls, grid no. 1, and magnetic filter rods. The measurements are presented for two different filament locations, for three different values of arc power, and for three values of source gas pressure. 1 ref., 4 figs., 2 tabs

  19. High-pressure ionization chambers for calorimetry in high-energy physics

    International Nuclear Information System (INIS)

    Measurements have been made with alpha particles in pure argon gas at pressures of up to 100 atm with only a 20% reduction in pulse height. Some of this is attributable to recombination at high pressures. With the addition of 0.2% methane and with an electric field of 1 kV/mm, the drift velocity of the electrons was 55 ns/mm. The objective is to produce a calorimeter that is fast, radiation hard, and free of the problems caused by scattered neutrons in low-pressure gas calorimetry

  20. Titration Calorimetry Applied to the Thermokinetics Study of Consecutive First-order Reactions

    Institute of Scientific and Technical Information of China (English)

    SHI Jing-Yan; LI Jie; WANG Zhi-Yong; LIU Yu-Wen; WANG Cun-Xin

    2008-01-01

    The thermokinetic mathematical models for consecutive first-order reactions in titration period and the stopped-titration reaction period were proposed for titration calorimetry, based on which, thermodynamic parameters (reaction enthalpies, △rHm1 and △rHm2) and kinetic parameters (rate constants, k1 and k2) of the consecutive first-order reactions could be obtained by directly simulating the calorimetric curve from a single experiment with the method of nonlinear least squares regression (NLLS).The reliability of the model has been verified by investigating the reaction of the saponification of diethyl succinate in an aqueous ethanol solvent.