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Sample records for calorimetry dsc experimental

  1. Differential scanning calorimetry (DSC) of semicrystalline polymers.

    Science.gov (United States)

    Schick, C

    2009-11-01

    Differential scanning calorimetry (DSC) is an effective analytical tool to characterize the physical properties of a polymer. DSC enables determination of melting, crystallization, and mesomorphic transition temperatures, and the corresponding enthalpy and entropy changes, and characterization of glass transition and other effects that show either changes in heat capacity or a latent heat. Calorimetry takes a special place among other methods. In addition to its simplicity and universality, the energy characteristics (heat capacity C(P) and its integral over temperature T--enthalpy H), measured via calorimetry, have a clear physical meaning even though sometimes interpretation may be difficult. With introduction of differential scanning calorimeters (DSC) in the early 1960s calorimetry became a standard tool in polymer science. The advantage of DSC compared with other calorimetric techniques lies in the broad dynamic range regarding heating and cooling rates, including isothermal and temperature-modulated operation. Today 12 orders of magnitude in scanning rate can be covered by combining different types of DSCs. Rates as low as 1 microK s(-1) are possible and at the other extreme heating and cooling at 1 MK s(-1) and higher is possible. The broad dynamic range is especially of interest for semicrystalline polymers because they are commonly far from equilibrium and phase transitions are strongly time (rate) dependent. Nevertheless, there are still several unsolved problems regarding calorimetry of polymers. I try to address a few of these, for example determination of baseline heat capacity, which is related to the problem of crystallinity determination by DSC, or the occurrence of multiple melting peaks. Possible solutions by using advanced calorimetric techniques, for example fast scanning and high frequency AC (temperature-modulated) calorimetry are discussed.

  2. 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.

  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. Applications of differential scanning calorimetry for thermal stability analysis of proteins: qualification of DSC.

    Science.gov (United States)

    Wen, Jie; Arthur, Kelly; Chemmalil, Letha; Muzammil, Salman; Gabrielson, John; Jiang, Yijia

    2012-03-01

    Differential scanning calorimetry (DSC) has been used to characterize protein thermal stability, overall conformation, and domain folding integrity by the biopharmaceutical industry. Recently, there have been increased requests from regulatory agencies for the qualification of characterization methods including DSC. Understanding the method precision can help determine what differences between samples are significant and also establish the acceptance criteria for comparability and other characterization studies. In this study, we identify the parameters for the qualification of DSC for thermal stability analysis of proteins. We use these parameters to assess the precision and sensitivity of DSC and demonstrate that DSC is suitable for protein thermal stability analysis for these purposes. Several molecules from different structural families were studied. The experiments and data analyses were performed by different analysts using different instruments at different sites. The results show that the (apparent) thermal transition midpoint (T(m)) values obtained for the same protein by same and different instruments and/or analysts are quite reproducible, and the profile similarity values obtained for the same protein from the same instrument are also high. DSC is an appropriate method for assessing protein thermal stability and conformational changes.

  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.

  6. Prediction of the self-accelerating decomposition temperature (SADT) for liquid organic peroxides from differential scanning calorimetry (DSC) measurements.

    Science.gov (United States)

    Malow, M; Wehrstedt, K D

    2005-04-11

    We present a prediction (estimation, calculation, screening) method for the estimation of the self-accelerating decomposition temperature (SADT) for liquid organic peroxides from differential scanning calorimetry (DSC) measurements based on the concepts of thermal explosion theory originally introduced by Semonov which are adopted to our problem assuming nth-order reaction kinetics. For the peroxides under investigation, we demonstrate good agreement with the experimental SADT. This method can be used as a quick and easy applicable method for the estimation of the critical temperatures.

  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. Monitoring of butter and animal fat oxidation stability by differential scanning calorimetry (DSC

    Directory of Open Access Journals (Sweden)

    Jasminka Sadadinović

    2005-07-01

    Full Text Available Oxidation of fat is one of the basic reactions which causes the depletion of butter and animal fat quality as well as other products containing them. Since the most of reaction products of fat oxidation are harmful for consumers' health, inadequate and scarce monitoring of edible fats and fat containing products quality, presents increased health risk as well as financial loss for the producers. In fat oxidation stability estimation, standard chemical methods were used (iodine number, acid number, peroxide number, anisidine number etc., which require time and chemical usage. Differential scanning calorimetry (DSC analysis presents the simple and efficient way for butter and animal fats oxidation stability estimation. Laboratory investigations were performed to monitor oxidation stability of butter and animal fat in fresh state, as well as in spent phase, used in frying process. The results obtained were compared to the results of standard chemical analysis, and they confirmed the reproducibility and applicability of differential scanning calorimetry in oxidation stability of butter and animal fats monitoring.

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

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    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

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

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    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.

  11. Determination of melting point of vegetable oils and fats by differential scanning calorimetry (DSC technique.

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    Nassu, Renata Tieko

    1999-02-01

    Full Text Available Melting point of fats is used to characterize oils and fats and is related to their physical properties, such as hardness and thermal behaviour. The present work shows the utilization of DSC technique on the determination of melting point of fats. In a comparison with softening point (AOCS method Cc 3-25, DSC values were higher than those obtained by AOCS method. It has occurred due to the fact that values obtained by DSC technique were taken when the fat had melted completely. DSC was also useful for determining melting point of liquid oils, such as soybean and cottonseed ones.

    El punto de fusión de grasas es usado para caracterizar aceites y grasas, y está relacionado con sus propiedades físicas, tales como dureza y comportamiento térmico. El presente trabajo muestra la utilización de la técnica de Calorimetría Diferencial de Barrido (DSC en la determinación del punto de fusión de grasas. En comparación con el punto de ablandamiento (AOCS método Cc 3-25, los valores de DSC fueron más altos que los obtenidos por los métodos de AOCS. Esto ha ocurrido debido al hecho que los valores obtenidos por la técnica de DSC fueron tomados cuando la grasa había fundido completamente. DSC fue también útil para determinar puntos de fusión de aceites líquidos, tales como los de soya y algodón.

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

    DEFF Research Database (Denmark)

    Knopp, Matthias Manne; Löbmann, Korbinian; Elder, David P.

    2016-01-01

    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...

  13. 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.

  14. Differential scanning calorimetry (DSC) as a tool for probing the reactivity of polyynes relevant to hexadehydro-Diels-Alder (HDDA) cascades.

    Science.gov (United States)

    Woods, Brian P; Hoye, Thomas R

    2014-12-19

    The differential scanning calorimetry (DSC) behavior of a number of alkyne-rich compounds is described. The DSC trace for each compound exhibits an exothermic event at a characteristic onset temperature. For the tri- and tetraynes whose [4 + 2] HDDA reactivity in solution has been determined, these onset temperatures show a strong correlation with the cyclization activation energy. The studies reported here exemplify how the data available through this operationally simple analytical technique can give valuable insights into the thermal behavior of small molecules.

  15. Investigation of Phase Mixing in Amorphous Solid Dispersions of AMG 517 in HPMC-AS Using DSC, Solid-State NMR, and Solution Calorimetry.

    Science.gov (United States)

    Calahan, Julie L; Azali, Stephanie C; Munson, Eric J; Nagapudi, Karthik

    2015-11-02

    Intimate phase mixing between the drug and the polymer is considered a prerequisite to achieve good physical stability for amorphous solid dispersions. In this article, spray dried amorphous dispersions (ASDs) of AMG 517 and HPMC-as were studied by differential scanning calorimetry (DSC), solid-state NMR (SSNMR), and solution calorimetry. DSC analysis showed a weakly asymmetric (ΔTg ≈ 13.5) system with a single glass transition for blends of different compositions indicating phase mixing. The Tg-composition data was modeled using the BKCV equation to accommodate the observed negative deviation from ideality. Proton spin-lattice relaxation times in the laboratory and rotating frames ((1)H T1 and T1ρ), as measured by SSNMR, were consistent with the observation that the components of the dispersion were in intimate contact over a 10-20 nm length scale. Based on the heat of mixing calculated from solution calorimetry and the entropy of mixing calculated from the Flory-Huggins theory, the free energy of mixing was calculated. The free energy of mixing was found to be positive for all ASDs, indicating that the drug and polymer are thermodynamically predisposed to phase separation at 25 °C. This suggests that miscibility measured by DSC and SSNMR is achieved kinetically as the result of intimate mixing between drug and polymer during the spray drying process. This kinetic phase mixing is responsible for the physical stability of the ASD.

  16. 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.

  17. 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

  18. Can the thermodynamic melting temperature of sucrose, glucose, and fructose be measured using rapid-scanning differential scanning calorimetry (DSC)?

    Science.gov (United States)

    Lee, Joo Won; Thomas, Leonard C; Schmidt, Shelly J

    2011-04-13

    The loss of crystalline structure in sucrose, glucose, and fructose has been shown to be due to the kinetic process of thermal decomposition (termed apparent melting), rather than thermodynamic melting. The purpose of this research was to investigate whether or not it is possible to scan quickly enough to suppress the kinetic process of thermal decomposition and reach the thermodynamic melting temperature of these sugars using a new rapid-scanning DSC. Indium, a thermodynamic melting material, and sucrose, glucose, and fructose were analyzed at three heating rates from 1 to 25 °C/min using standard DSC and at seven heating rates from 50 to 2000 °C/min using rapid-scanning DSC. Thermodynamic melting was achieved when the onset temperature (T(m onset)) of the endothermic peak leveled off to a constant value independent of heating rate. The T(m onset) for indium was constant (156.74 ± 0.42 °C) at all heating rates. In the case of fructose, the T(m onset) increased considerably until a heating rate of approximately 698 °C/min, after which the average T(m onset) for the remaining three heating rates was constant at 135.83 ± 1.14 °C. Thus, 135.83 °C is proposed to be the thermodynamic melting temperature of fructose. It is important to note that the heating rate at which this thermodynamic melting temperature is achieved is most likely influenced by the type and amount of trace components (e.g., water and salts) contained in the fructose, which are known to vary widely in sugars. In the case of sucrose and glucose, thermodynamic melting temperatures were not able to be obtained, because the upper limit heating rate used was not fast enough to suppress thermal decomposition and achieve thermodynamic melting, perhaps due to the higher apparent T(m onset) for sucrose and glucose compared to that for fructose.

  19. 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.

  20. Differential scanning calorimetry techniques: applications in biology and nanoscience.

    Science.gov (United States)

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

    2010-12-01

    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.

  1. Application of Differential Scanning Calorimetry (DSC) in Analysis of Oils%差示扫描量热法(DSC)在油脂分析中的应用

    Institute of Scientific and Technical Information of China (English)

    宋菲; 王挥; 陈卫军; 赵松林

    2014-01-01

    In the research of physical properties and the processing products of oils, differential scanning calorimetry (DSC) as a thermal analysis technology is widely used. This paper introduces the application of DSC in the determination of oil composition, crystallization and melting, oxidation and oxidation kinetics and adulteration of oils. This thermal analysis method has very broad prospects in oil scientific research and actual production.%介绍差示扫描量热法(DSC)在测定油脂的组分、结晶与融化、氧化及氧化动力学和油脂掺假等方面的应用,以及热分析法在油脂的科学理论研究和实际生产中的应用前景。

  2. Differential scanning calorimetry.

    Science.gov (United States)

    Spink, Charles H

    2008-01-01

    Differential scanning calorimetry (DSC) has emerged as a powerful experimental technique for determining thermodynamic properties of biomacromolecules. The ability to monitor unfolding or phase transitions in proteins, polynucleotides, and lipid assemblies has not only provided data on thermodynamic stability for these important molecules, but also made it possible to examine the details of unfolding processes and to analyze the characteristics of intermediate states involved in the melting of biopolymers. The recent improvements in DSC instrumentation and software have generated new opportunities for the study of the effects of structure and changes in environment on the behavior of proteins, nucleic acids, and lipids. This review presents some of the details of application of DSC to the examination of the unfolding of biomolecules. After a brief introduction to DSC instrumentation used for the study of thermal transitions, the methods for obtaining basic thermodynamic information from the DSC curve are presented. Then, using DNA unfolding as an example, methods for the analysis of the melting transition are presented that allow deconvolution of the DSC curves to determine more subtle characteristics of the intermediate states involved in unfolding. Two types of transitions are presented for analysis, the first example being the unfolding of two large synthetic polynucleotides, which display high cooperativity in the melting process. The second example shows the application of DSC for the study of the unfolding of a simple hairpin oligonucleotide. Details of the data analysis are presented in a simple spreadsheet format.

  3. Thermal: Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), and Polarized Microscopy Instrumentation for the Analysis of Field-Controlled Anisotropic Nanomaterials

    Science.gov (United States)

    2014-11-14

    using DSC. ΔH = KA (eq. 1) Enthalpies of transition, ΔH, may easily be calculated from a DSC plot using equation 1. Here K... contribute to the enhanced sensitivity, resolution and baseline linearity/repeatability (±5µW) of the Discovery Series instruments. The Discovery...chromophores (xz, yz planes) and the coumarin pendant groups (x-y plane) are shown. c) A cartoon illustrating the bulk coumarin orientations present in

  4. 差示扫描量热法(DSC)及其在沥青研究中的应用%Differential scanning calorimetry (DSC) and its application in asphalt study

    Institute of Scientific and Technical Information of China (English)

    胡国玲; 朱治玲; 郭晓玲

    2005-01-01

    介绍了差示扫描量热法(DSC)的原理、设备、用途及注意事项,从DSC的曲线图和性能评定两方面,对其在沥青性能研究中的应用作了进一步的阐述,指出差示扫描量热法在沥青性能研究中有着广阔的应用前景.

  5. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Simon, Christian, E-mail: ch.simon@uni-muenster.de; Peterlechner, Martin; Wilde, Gerhard

    2015-03-10

    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 Ni{sub 49.9}–Ti{sub 50.1} 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.

  7. 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.

  8. DSC studies of gamma irradiation influence on gelatinisation and amylose-lipid complex transition occurring in wheat starch[Wheat starch; Gelatinisation; Amylose-lipid complex transition; Gamma irradiation; Differential scanning calorimetry, DSC

    Energy Technology Data Exchange (ETDEWEB)

    Ciesla, K. E-mail: kciesla@orange.ichtj.waw.pl; Eliasson, A.-C

    2003-12-01

    Differential scanning calorimetry studies are presented dealing with the influence of gamma irradiation (carried out in the solid state) on the structure of amylose-lipid complex in wheat starch. Suspensions of the control and the wheat starch irradiated with a 30 kGy gamma rays (characterised by starch-to-water ratio of 1:1 and ca. 1:4) were examined during several courses of heating and cooling at rates of 2.5 and 10 deg. C min{sup -1}. Differences were observed between enthalpy and temperature of gelatinisation and amylose-lipid complex transition as well as retrogradation taking place in the suspensions and gels of the control and the irradiated starch. The influence of the preceding heating and cooling on further transformations of the amylose-lipid complex differs for the control and the irradiated samples.

  9. Application of differential scanning calorimetry (DSC), HPLC and pNMR for interpretation primary crystallisation caused by combined low and high melting TAGs.

    Science.gov (United States)

    Saadi, Sami; Ariffin, Abdul Azis; Ghazali, Hasanah Mohd; Miskandar, Mat Sahri; Boo, Huey Chern; Abdulkarim, Sabo Mohammed

    2012-05-01

    The main goal of the present work was to assess the mechanism of crystallisation, more precisely the dominant component responsible for primary crystal formations and fat agglomerations. Therefore, DSC results exhibited significant effect on temperature transition; peak sharpness and enthalpy at palm stearin (PS) levels more than 40wt.%. HPLC data demonstrated slight reduction in the content of POO/OPO at PS levels less than 40wt.%, while the excessive addition of PS more than 40wt.% increased significantly PPO/POP content. The pNMR results showed significant drop in SFC for blends containing PS less than 40wt.%, resulting in low SFC less than 15% at body temperature (37°C). Moreover, the values of viscosity (η) and shear stress (τ) at PS levels over 40wt.% expressed excellent internal friction of the admixtures. All the data reported indicate that PPO/POP was the major component of primary nucleus developed. In part, the levels of PS should be less than 40wt.%, if these blends are designed to be used for margarine production.

  10. Effect of milling on DSC thermogram of excipient adipic acid.

    Science.gov (United States)

    Ng, Wai Kiong; Kwek, Jin Wang; Yuen, Aaron; Tan, Chin Lee; Tan, Reginald

    2010-03-01

    The purpose of this research was to investigate why and how mechanical milling results in an unexpected shift in differential scanning calorimetry (DSC) measured fusion enthalpy (Delta(fus)H) and melting point (T(m)) of adipic acid, a pharmaceutical excipient. Hyper differential scanning calorimetry (hyper-DSC) was used to characterize adipic acid before and after ball-milling. An experimental study was conducted to evaluate previous postulations such as electrostatic charging using the Faraday cage method, crystallinity loss using powder X-ray diffraction (PXRD), thermal annealing using DSC, impurities removal using thermal gravimetric analysis (TGA) and Karl Fischer titration. DSC thermograms showed that after milling, the values of Delta(fus)H and T(m) were increased by approximately 9% and 5 K, respectively. Previous suggestions of increased electrostatic attraction, change in particle size distribution, and thermal annealing during measurements did not explain the differences. Instead, theoretical analysis and experimental findings suggested that the residual solvent (water) plays a key role. Water entrapped as inclusions inside adipic acid during solution crystallization was partially evaporated by localized heating at the cleaved surfaces during milling. The correlation between the removal of water and melting properties measured was shown via drying and crystallization experiments. These findings show that milling can reduce residual solvent content and causes a shift in DSC results.

  11. 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....... The bovine serum measurements show two main peaks, in good agreement with standard DSC measurements. Olive oil has been measured, with good agreement for the cooling curve and qualitative agreement for the heater curve, compared to DSC measurements....

  12. 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

    Directory of Open Access Journals (Sweden)

    Fábio Akira Mori

    2002-08-01

    Full Text Available 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 reação mais próximos aos do adesivo comercial de taninos de acácia-negra, que foram totalmente diferentes do adesivo à base de fenol-formaldeído. Com base nestes parâmetros constatou-se que, em relação aos outros dois, o adesivo de taninos de Eucalyptus urophylla é o mais adequado para colagem, uma vez que em condições industriais ele necessitará de uso mínimo de energia e de tempo de prensagem durante o processo de colagem.This work aimed to analyze the cure kinetics of Eucalyptus grandis, Eucalyptus saligna and Eucalyptus urophylla tannins based adhesives by differential scanning calorimetry (DSC. Another objective was to compare cure kinetics of Eucalyptus tannin adhesives with the cure kinetics of phenol-formaldehyde and Wattle black (Acacia mollissima D. Wild tannin commercial adhesives. It was observed that the Eucalyptus urophylla tannin adhesives presented kinetic parameters (activation energy, entalpia, peak temperature and reaction order similar to the Wattle black commercial tannin adhesives but were different from the phenol-formaldehyde adhesives. Based on these parameters it was concluded that the Eucalyptus urophylla tannin adhesives are more adequate for wood bonding than the other two Eucalyptus tannin adhesives. Under industrial conditions, Eucalyptus urophylla tannin adhesive will need a minimum energy and pressing.

  13. Analysis of RNA folding and ligand binding by conventional and high-throughput calorimetry.

    Science.gov (United States)

    Sokoloski, Joshua E; Bevilacqua, Philip C

    2012-01-01

    Noncoding RNAs serve myriad functions in the cell, but their biophysical properties are not well understood. Calorimetry offers direct and label-free means for characterizing the ligand-binding and thermostability properties of these RNA. We apply two main types of calorimetry--isothermal titration calorimetry (ITC) and differential scanning calorimetry (DSC)--to the characterization of these functional RNA molecules. ITC can describe ligand binding in terms of stoichiometry, affinity, and heat (enthalpy), while DSC can provide RNA stability in terms of heat capacity, melting temperature, and folding enthalpy. Here, we offer detailed experimental protocols for studying such RNA systems with commercially available conventional and high-throughput ITC and DSC instruments.

  14. The Yang-Yang anomaly in liquid-liquid criticality: Experimental evidence from adiabatic scanning calorimetry

    Science.gov (United States)

    Losada-Pérez, Patricia; Tripathi, Chandra Shekhar Pati; Leys, Jan; Cerdeiriña, Claudio A.; Glorieux, Christ; Thoen, Jan

    2012-01-01

    Using adiabatic scanning calorimetry, we have found the first experimental evidence of the Yang-Yang anomaly in liquid-liquid criticality from high-resolution two-phase isobaric heat capacity measurements for the binary mixture 3-pentanol + nitromethane. The results suggest a rather strong effect. The critical amplitude of the partial molar heat capacity is higher for the component with larger molecular volume, in accordance with the predictions of complete scaling as obtained from the customary observed asymmetric behavior of the coexistence-curve diameter. This consolidates complete scaling as the true formulation of fluid-fluid criticality. The quantitative analysis indicates that molecular size is not the only microscopic factor at play in asymmetric liquid-liquid criticality.

  15. The Use of Differential Scanning Calorimetry in Studies of Wax Deposition: Measuring the Solid Formation and Binary Solid-Liquid Equilibrium Phase Diagrams La DSC (Differential Scanning Calorimetry appliquée à l'étude des dépôts de paraffines : mesure des quantités de dépôts et des diagrammes de phases (liquide-solide de mélange binaire

    Directory of Open Access Journals (Sweden)

    Coutinho J. A. P.

    2006-12-01

    Full Text Available The studies of wax formation in hydrocarbon mixtures, both crudes and refined products such as diesels and fuels, require measuring techniques able to deal with the solid phase behaviour. Experimental data on phase equilibria is important to understand the crystallisation of paraffins and for the development of thermodynamical models, that can describe it. It is here shown how the information obtained from Differential Scanning Calorimetry (DSC measurements can be used to assess the amount of solid forming when a fluid is cooled and also to make faster measurements of phase diagrams for binary systems where no solid solutions exist. The measurements performed with the proposed methods present a good agreement with literature data. L'étude de la cristallisation des paraffines dans les mélanges hydrocarbonés, qu'il s'agisse de pétroles bruts ou de produits raffinés tels que le Diesel ou le fioul, nécessite l'utilisation de techniques expérimentales permettant de déterminer le diagramme de phases. L'acquisition de ces données est primordiale, à la fois pour comprendre les mécanismes de la cristallisation et pour le développement des modèles thermodynamiques. Dans cet article, nous montrons comment l'analyse calorimétrique différentielle peut permettre d'estimer la quantité de solide déposée en fonction de la température et de mesurer les diagrammes de phases de mélanges binaires ne formant pas de solutions solides. Les résultats obtenus avec la méthode proposée s'accordent avec les données de la littérature.

  16. DSC Study of Collagen in Disc Disease

    OpenAIRE

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

    2009-01-01

    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...

  17. Raman detected differential scanning calorimetry of polymorphic transformations in acetaminophen.

    Science.gov (United States)

    Kauffman, John F; Batykefer, Linda M; Tuschel, David D

    2008-12-15

    Acetaminophen is known to crystallize in three polymorphic forms. Thermally induced transformations between the crystalline forms and the super-cooled liquid have been observed by differential scanning calorimetry (DSC), but the assignment of calorimetric transitions to specific polymorphic transformations remains challenging, because the transition temperatures for several transformations are close to one another, and the characteristics of the observed transitions depend on experimental variables that are often poorly controlled. This paper demonstrates the simultaneous application of DSC and Raman microscopy for the observation of thermally driven transitions between polymorphs of pharmaceutical materials. Raman detected differential scanning calorimetry (RD-DSC) has been used to monitor the DSC thermograms of super-cooled liquid acetaminophen and confirms the assignment of two exothermic transitions to specific polymorphic transformations. Principal component analysis of the Raman spectra have been used to determine the number of independent components that participate in the phase transformations, and multivariate regression has been used to determine transition temperatures from the spectral data. The influence of the laser excitation source on measured DSC thermograms has also been investigated, and it has been demonstrated that a baseline shift occurs in RD-DSC when a polymorphic transformation occurs between crystalline and amorphous forms. RD-DSC has been used to examine the influence of sample aging and sample pan configuration on the observed polymorphic transformations, and both of these variables were found to influence the thermal behavior of the sample. The results demonstrate the advantage of simultaneous Raman spectroscopy and differential scanning calorimetry for the unambiguous assignment of thermally driven polymorphic transformations.

  18. 差示扫描量热法在蛋白质热变性研究中的应用%The application of differential scanning calorimetry (DSC) in the protein thermal denaturation

    Institute of Scientific and Technical Information of China (English)

    易薇; 胡一桥

    2004-01-01

    目的介绍差示扫描量热法(DSC)在蛋白质热变性研究中的应用.方法以大量具有代表性的文献为依据,讨论如何运用DSC技术研究蛋白质热变性的原因与影响因素及蛋白质热变性与生理活性的关系.结果与结论 DSC在蛋白质热变性研究中的应用有广阔的发展前景.

  19. Modern Analysis of Protein Folding by Differential Scanning Calorimetry.

    Science.gov (United States)

    Ibarra-Molero, Beatriz; Naganathan, Athi N; Sanchez-Ruiz, Jose M; Muñoz, Victor

    2016-01-01

    Differential scanning calorimetry (DSC) is a very powerful tool for investigating protein folding and stability because its experimental output reflects the energetics of all conformations that become minimally populated during thermal unfolding. Accordingly, analysis of DSC experiments with simple thermodynamic models has been key for developing our understanding of protein stability during the past five decades. The discovery of ultrafast folding proteins, which have naturally broad conformational ensembles and minimally cooperative unfolding, opens the possibility of probing the complete folding free energy landscape, including those conformations at the top of the barrier to folding, via DSC. Exploiting this opportunity requires high-quality experiments and the implementation of novel analytical methods based on statistical mechanics. Here, we cover the recent exciting developments in this front, describing the new analytical procedures in detail as well as providing experimental guidelines for performing such analysis.

  20. Application and use of isothermal calorimetry in pharmaceutical development.

    Science.gov (United States)

    O'Neill, Michael A A; Gaisford, Simon

    2011-09-30

    There are many steps involved in developing a drug candidate into a formulated medicine and many involve analysis of chemical interaction or physical change. Calorimetry is particularly suited to such analyses as it offers the capacity to observe and quantify both chemical and physical changes in virtually any sample. Differential scanning calorimetry (DSC) is ubiquitous in pharmaceutical development, but the related technique of isothermal calorimetry (IC) is complementary and can be used to investigate a range of processes not amenable to analysis by DSC. Typically, IC is used for longer-term stability indicating or excipient compatibility assays because both the temperature and relative humidity (RH) in the sample ampoule can be controlled. However, instrument design and configuration, such as titration, gas perfusion or ampoule-breaking (solution) calorimetry, allow quantification of more specific values, such as binding enthalpies, heats of solution and quantification of amorphous content. As ever, instrument selection, experiment design and sample preparation are critical to ensuring the relevance of any data recorded. This article reviews the use of isothermal, titration, gas-perfusion and solution calorimetry in the context of pharmaceutical development, with a focus on instrument and experimental design factors, highlighted with examples from the recent literature.

  1. Nucleic acid-lipid membrane interactions studied by DSC.

    Science.gov (United States)

    Giatrellis, Sarantis; Nounesis, George

    2011-01-01

    The interactions of nucleic acids with lipid membranes are of great importance for biological mechanisms as well as for biotechnological applications in gene delivery and drug carriers. The optimization of liposomal vectors for clinical use is absolutely dependent upon the formation mechanisms, the morphology, and the molecular organization of the lipoplexes, that is, the complexes of lipid membranes with DNA. Differential scanning calorimetry (DSC) has emerged as an efficient and relatively easy-to-operate experimental technique that can straightforwardly provide data related to the thermodynamics and the kinetics of the DNA-lipid complexation and especially to the lipid organization and phase transitions within the membrane. In this review, we summarize DSC studies considering nucleic acid-membrane systems, accentuating DSC capabilities, and data analysis. Published work involving cationic, anionic, and zwitterionic lipids as well as lipid mixtures interacting with RNA and DNA of different sizes and conformations are included. It is shown that despite limitations, issues such as DNA- or RNA-induced phase separation and microdomain lipid segregation, liposomal aggregation and fusion, alterations of the lipid long-range molecular order, as well as membrane-induced structural changes of the nucleic acids can be efficiently treated by systematic high-sensitivity DSC studies.

  2. Experimental determination of the (vapor + liquid) equilibrium data of binary mixtures of fatty acids by differential scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Matricarde Falleiro, Rafael M. [LPT, Department of Chemical Processes (DPQ), School of Chemical Engineering, University of Campinas (UNICAMP), P.O. Box 6066, 13083-970 Campinas, SP (Brazil); Meirelles, Antonio J.A. [EXTRAE, Department of Food Engineering (DEA), School of Food Engineering, University of Campinas (UNICAMP), P.O. Box 6121, 13083-862 Campinas, SP (Brazil); Kraehenbuehl, Maria A., E-mail: mak@feq.unicamp.b [LPT, Department of Chemical Processes (DPQ), School of Chemical Engineering, University of Campinas (UNICAMP), P.O. Box 6066, 13083-970 Campinas, SP (Brazil)

    2010-01-15

    (Vapor + liquid) equilibrium (VLE) data for three binary mixtures of saturated fatty acids were obtained by differential scanning calorimetry (DSC). However, changes in the calorimeter pressure cell and the use of hermetic pans with holes (phi = 250 mm) in the lids were necessary to make it possible to apply this analytical technique, obtaining accurate results with smaller samples and shorter operational times. The systems evaluated in this study were: myristic acid (C{sub 14:0}) + palmitic acid (C{sub 16:0}), myristic acid (C{sub 14:0}) + stearic acid (C{sub 18:0}), and palmitic acid (C{sub 16:0}) + stearic acid (C{sub 18:0}), all measured at 50 mm Hg and with mole fractions between 0.0 and 1.0 in relation to the most volatile component of each diagram. The fugacity coefficients for the components in the vapor phase were calculated using the Hayden and O'Connell method [J.G. Hayden, J.P. O'Connell, Ind. Eng. Chem. Process Design Develop. 14 (3) (1975) 209-216] and the activity coefficients for the liquid phase were correlated with the traditional g{sup E} models (NRTL [H. Renon, J.M. Prausnitz, Aiche J. 14 (1968) 135-144], UNIQUAC [D.S. Abrams, J.M. Prausnitz, Aiche J. 21 (1975) 116-128], and Wilson [J.M. Prausnitz, N.L. Linchtenthaler, E.G. Azevedo, Molecular Thermodynamics of Fluid-phase Equilibria, River-Prentice Hall, Upper Saddle, 1999]). The sets of parameters were then compared in order to determine which adjustments best represented the VLE.

  3. Investigação da cinética de cura por calorimetria diferencial exploratória (DSC de resinas epóxi preparadas a partir de óleo de soja epoxidado com diferentes anidridos e aminas terciárias Investigation of the kinetics of cure by differential scanning calorimetry (DSC of epoxy resins prepared from epoxidized soybean oil with different anhydrides and tertiary amines

    Directory of Open Access Journals (Sweden)

    Ana P. O. Costa

    2011-01-01

    Full Text Available No presente trabalho, utilizou-se a calorimetria diferencial exploratória (DSC para investigar a cinética da reação de cura de resinas epóxi produzidas a partir da reação do óleo de soja epoxidado (ESO, com os anidridos dodecenilsuccínico (DDS, maleico (MAL, ftálico (FTA, succínico (SUC e hexahidroftálico (CH, atuando como agentes de cura, e na presença de aminas terciárias como a trietilamina (TEA, a N,N'-dimetilanilina (ARO e a 1,4- diazobiciclo [2,2,2] octano (DABCO, atuando como catalisadores. A taxa de aquecimento, a natureza química e a estrutura do anidrido e das aminas influenciaram a reação de cura. Os métodos dinâmicos de Kissinger, Ozawa e de Barrett foram utilizados para calcular a energia de ativação dos sistemas onde se variou o anidrido. Observou-se que os anidridos mais reativos foram o DDS e maleico que apresentaram os menores valores de energias de ativação. No estudo da influência do catalisador, utilizou-se o método de Barrett para determinar as energias de ativação das reações com as diferentes aminas. A amina cicloaliafática (DABCO foi a mais reativa obtendo-se o menor valor de energia de ativação (Ea = 51 kJ.mol-1 e fator pré-exponencial (ln A0 = 9 s-1.In the present work, differential scanning calorimetry (DSC was used to investigate the curing reaction kinetics of epoxy resins produced from reaction of epoxidized soybean oil (ESO with cyclic anhydrides dodecenylsuccinic (DDS, maleic (MAL, phthalic (PA, succinic (SUC and hexahydrophthalic (CH, in the presence of tertiary amines such as triethylamine (TEA, N,N-dimethylaniline (ARO and 1,4-diazabicyclo [2,2,2] octane (DABCO. The heating rate, the nature and structure of anhydrides and amines were found to affect the curing reaction. The dynamic methods of Kissinger, Ozawa and Barrett were used to calculate the activation energy of the reactions where different anhydrides were used. DDS and maleic anhydrides were more reactive than the others

  4. Calorimetry of Nucleic Acids.

    Science.gov (United States)

    Rozners, Eriks; Pilch, Daniel S; Egli, Martin

    2015-12-01

    This unit describes the application of calorimetry to characterize the thermodynamics of nucleic acids, specifically, the two major calorimetric methodologies that are currently employed: differential scanning (DSC) and isothermal titration calorimetry (ITC). DSC is used to study thermally induced order-disorder transitions in nucleic acids. A DSC instrument measures, as a function of temperature (T), the excess heat capacity (C(p)(ex)) of a nucleic acid solution relative to the same amount of buffer solution. From a single curve of C(p)(ex) versus T, one can derive the following information: the transition enthalpy (ΔH), entropy (ΔS), free energy (ΔG), and heat capacity (ΔCp); the state of the transition (two-state versus multistate); and the average size of the molecule that melts as a single thermodynamic entity (e.g., the duplex). ITC is used to study the hybridization of nucleic acid molecules at constant temperature. In an ITC experiment, small aliquots of a titrant nucleic acid solution (strand 1) are added to an analyte nucleic acid solution (strand 2), and the released heat is monitored. ITC yields the stoichiometry of the association reaction (n), the enthalpy of association (ΔH), the equilibrium association constant (K), and thus the free energy of association (ΔG). Once ΔH and ΔG are known, ΔS can also be derived. Repetition of the ITC experiment at a number of different temperatures yields the ΔCp for the association reaction from the temperature dependence of ΔH.

  5. Indirect calorimetry

    NARCIS (Netherlands)

    Gerrits, W.J.J.; Labussière, E.

    2015-01-01

    The use of indirect calorimetry to measure the heat production of men and animals has increased rapidly since the pioneering work of Lavoisier. Measurement of the consumption of oxygen and production of carbon dioxide are the basis for the measurement of heat production. Today, applications of indir

  6. 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

  7. 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

  8. 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.

  9. Characterization of the polycaprolactone melt crystallization: complementary optical microscopy, DSC, and AFM studies.

    Science.gov (United States)

    Speranza, V; Sorrentino, A; De Santis, F; 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 to detect the first stages of crystallization. On the contrary, at least in the case analysed in this work, rheology appears to be the least sensitive technique. DSC and POM provide closer results. This suggests that the definition of induction time in the polymer crystallization is a vague concept that, in any case, requires the definition of the technique used for its characterization.

  10. 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)

  11. Characterisation of gas hydrates formation and dissociation using high pressure DSC

    Energy Technology Data Exchange (ETDEWEB)

    Le Parlouer, P. [Thermal Consulting, Caluire (France); Etherington, G. [Setaram Inc., Pennsauken, NJ (United States)

    2008-07-01

    This paper provided details of an innovative methodology that used a high pressure micro-scale differential scanning calorimetry (DSC) method to characterize the thermodynamic properties and kinetics of gas hydrate formation. The calorimeter was based on a symmetrical heat flux design that used a Peltier cooling and heating principle. No refrigerating fluids were required. The method described phase transitions in relation to time, temperature and pressure. The DSC method was designed for use with gas hydrates trapped in marine sediments; hydrate formation in drilling muds and annulars during offshore oil and gas extraction; the storage and transportation of natural gas; and gas hydrate formation and dissociation for cold storage and transportation. Tests demonstrated that the DSC accurately predicted the formation of gas hydrates under high pressure conditions. Experimental studies were conducted to investigate salt solutions under methane pressure; and hydrate dissociation in a sodium chloride (NaC1) and ethyleneglycol solution. Data obtained comparing the method with classical PVT techniques showed that the MicroDSC technique was less time-consuming and required smaller sample volumes. It was concluded that the method is suitable for use with various types of fluids. 13 refs., 7 figs.

  12. 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.

  13. Evaluation of enthalpy change due to hydrogen desorption for lithium amide/imide system by differential scanning calorimetry

    OpenAIRE

    2008-01-01

    Enthalpy change (ΔH) due to hydrogen desorption (H-desorption) for the lithium amide/imide system was evaluated by differential scanning calorimetry (DSC) measurement. In order to obtain the accurate and precise value of ΔH, we have paid special attention to following two points for correcting raw experimental data. One is to determine a cell constant of DSC equipment, which was evaluated by using the TiO2-doped MgH2 compound as a reference because of its quite similar hydrogen desorption pro...

  14. Physical ageing studies of poly(ethylene terephthalate) using SANS and DSC

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, Andrew [Department of Metallurgy and Materials, University of Birmingham, Birmingham B15 2TT (United Kingdom); Gordon, Duncan [Department of Metallurgy and Materials, University of Birmingham, Birmingham B15 2TT (United Kingdom); King, Stephen [ISIS Spallation Neutron Source, Rutherford-Appleton Laboratory, Didcot, Oxfordshire OX11 0QX (United Kingdom); Jenkins, Mike [Department of Metallurgy and Materials, University of Birmingham, Birmingham B15 2TT (United Kingdom)]. E-mail: M.J.Jenkins@bham.ac.uk

    2006-11-15

    The process of physical ageing in a blend of deuterated and hydrogenated poly(ethylene terephalate) has been investigated using a combination of differential scanning calorimetry (DSC) and small-angle neutron scattering (SANS). The development of an endothermic peak on the glass transition has been shown using DSC. Furthermore, the radius of gyration was found to decrease during physical ageing.

  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. 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.

  17. Determination of the oxidative stability by DSC of vegetable oils from the Amazonian area.

    Science.gov (United States)

    Pardauil, Juliana J R; Souza, Luiz K C; Molfetta, Fábio A; Zamian, José R; Rocha Filho, Geraldo N; da Costa, C E F

    2011-05-01

    Differential scanning calorimetry (DSC) and a Rancimat method apparatus were applied to evaluate the oxidative stability of buriti pulp oil (Mauritia flexuosa Mart), rubber seed oil (Hevea brasiliensis), and passion fruit oil (Passiflora edulis). The Rancimat measurements taken for the oxidative induction times were performed under isothermal conditions at 100°C and in an air atmosphere. The DSC technique involved the oxidation of oil samples in an oxygen-flow DSC cell. The DSC cell temperature was set at five different isothermal temperatures: 100, 110, 120, 130 and 140°C. During the oxidation reaction, an increase in heat was observed as a sharp exothermic curve. The value T(0) represents the oxidative induction time, which is determined from the downward extrapolated DSC oxidative curve verses the time axis. These curves indicate a good correlation between the DSC T(0) and oxidative stability index (OSI) values. The DSC method is useful because it consumes less time and less sample.

  18. The slow relaxation dynamics in active pharmaceutical ingredients studied by DSC and TSDC: Voriconazole, miconazole and itraconazole.

    Science.gov (United States)

    Ramos, Joaquim J Moura; Diogo, Hermínio P

    2016-03-30

    The slow molecular mobility of three active pharmaceutical drugs (voriconazole, miconazole and itraconazole) has been studied by differential scanning calorimetry (DSC) and thermally stimulated depolarization currents (TSDC). This study yielded the main kinetic features of the secondary relaxations and of the main (glass transition) relaxation, in particular their distribution of relaxation times. The dynamic fragility of the three glass formers was determined from DSC data (using two different procedures) and from TSDC data. According to our results voriconazole behaves as a relatively strong liquid, while miconazole is moderately fragile and itraconazole is a very fragile liquid. There are no studies in this area published in the literature relating to voriconazole. Also not available in the literature is a slow mobility study by dielectric relaxation spectroscopy in the amorphous miconazole. Apart from that, the results obtained are in reasonable agreement with published works using different experimental techniques.

  19. Temperature Dependence of Dynamic Viscosity and DSC Analysis of the Plantohyd samples

    Directory of Open Access Journals (Sweden)

    Vlasta Vozarova

    2015-06-01

    Full Text Available The present work deals with physical properties – dynamic viscosity and DSC analysis of biodegradable hydraulic fluids and lubricating oils based on vegetable oils or on synthetic esters – PLANTOHYD S series (15S, 46S and PLANTOHYD N series (40N. The brief characterization of investigated material is presented. This article presents the experimental results of measuring the main rheological characteristic – dynamic viscosity of samples of Plantohyd. Measurements were made under laboratory conditions with digital viscometer DV-3P Anton Paar. Examination of the dynamic viscosity in the temperature interval from -10 °C to 50 °C was made. The exponential dependency of viscosity on the temperature for the each sample was obtained in accordance with Arrhenius equation. DSC (Differential Scanning Calorimetry analysis providing information on thermal effects in the sample subjected to the temperature programme was realised in the temperature range from -30 °C to 100 °C by using differential scanning calorimeter DSC 822e METTLER TOLEDO. It was determined endo/exo thermal effects and temperature interval with no thermal effects for each sample of Plantohyd.

  20. DSC Study of Collagen in Disc Disease

    Directory of Open Access Journals (Sweden)

    S. Skrzyński

    2009-01-01

    Full Text Available 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 tissue from healthy patients and from patients suffering from disc disease. In the paper the comparison between thermal helix-coil transition for collagen fibers from patients suffering from disc disease and collagen fibers from healthy organisms has been discussed. The heating rate has an influence on the position on denaturation temperatures of collagen in disc tissues. Higher helix-coil transition temperature of collagen in degenerated disc suggests that additional intermolecular cross linking of collagen fibers occurs. Denaturation temperatures of collagen in degenerated male disc possess smaller values than in female ones. Disc disease induces changes in collagen structure and leads to formation of additional crosslinks between collagen fibers.

  1. Differential Scanning Calorimetry of Superelastic Nitinol for Tuneable Devices

    OpenAIRE

    Feeney, Andrew; LUCAS, MARGARET

    2015-01-01

    Nitinol has been used to fabricate tuneable-frequency cymbal transducers by exploiting its solid-state phase transformation capability. The temperatures at which Nitinol transforms\\ud are commonly measured using differential scanning calorimetry (DSC). However, these\\ud measurements are shown to be inaccurate for superelastic Nitinol, reportedly attributed to residual stresses in the material resulting from the fabrication process. This study of DSC accuracy is conducted for untreated and hea...

  2. Systematic investigation of lard polymorphism using combined DSC and time-resolved synchrotron X-ray diffraction

    NARCIS (Netherlands)

    Kalnin, D.J.E.; Lesieur, P.; Artzner, F.; Keller, G.; Ollivon, M.

    2005-01-01

    The polymorphic behavior of lard was systematically investigated by differential scanning calorimetry (DSC) while simultaneously monitoring the formation of the different crystal forms with X-ray diffraction (XRDT). To interpret the complex polymorphic evolution of the sample analyzed by regular DSC

  3. 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.

  4. DSC of human hair: a tool for claim support or incorrect data analysis?

    Science.gov (United States)

    Popescu, C; Gummer, C

    2016-10-01

    Differential scanning calorimetry (DSC) data are increasingly used to substantiate product claims of hair repair. Decreasing peak temperatures may indicate structural changes and chemical damage. Increasing the DSC, wet peak temperature is, therefore, often considered as proof of hair repair. A detailed understanding of the technique and hair structure indicates that this may not be a sound approach. Surveying the rich literature on the use of dynamic thermal analysis (DTA) and differential scanning calorimetry (DSC) for the analyses of human hair and the effect of cosmetic treatments, we underline some of the problems of hair structure and data interpretation. To overcome some of the difficulties of data interpretation, we advise that DSC acquired data should be supported by other techniques when used for claim substantiation. In this way, one can provide meaningful interpretation of the hair science and robust data for product claims support.

  5. Differential scanning calorimetry on mixtures of lecithin, lysolecithin and cholesterol

    NARCIS (Netherlands)

    Klopfenstein, W.E.; Kruyff, B. de; Verkleij, A.J.; Demel, R.A.; Deenen, L.L.M. van

    1974-01-01

    The effect of increasing concentrations of lysolecithin (1-palmitoyl-sn-glycerol-3-phosphorylcholine) on the gel → liquid crystal thermal transition of lecithin (1,2-dipalmitoyl-sn-glycerol-3-phosphorylcholine) in the aqueous phase was studied by differential scanning calorimetry (DSC). Lysolecithin

  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. 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.

  8. 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.

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

    DEFF Research Database (Denmark)

    Fessas, D.; Signorelli, M.; Schiraldi, A.;

    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 correlati...

  10. Rheological and DSC Studies on the Interaction between κ-Carrageenan and Cellulose Nanocrystals (CNC)

    Institute of Scientific and Technical Information of China (English)

    Rui GUO; En Yong DING

    2006-01-01

    Rheometer and differential scanning calorimetry (DSC) have been used to probe the mechanism of gelation in gels formed by mixture of κ-carrageenan and cellulose nanocrystals (CNC). The results indicated that an association occurred between CNC chains and aggregated κ-carrageenan helices.

  11. DSC and NMR Study on the Inclusion Complex of Lappaconitine with β—Cyclodextrin

    Institute of Scientific and Technical Information of China (English)

    KaiJunLIAO; XiaoHuaYAN; 等

    2002-01-01

    The inclusion complex of lappaconitine(Lap) with β-cyclodextrin (β-CD) has been studied by the differential scanning calorimetry (DSC) and 1H-NMR,2D-NMR spectroscopy. The structure of the complex has been deduced.

  12. DSC and NMR Study on the Inclusion Complex of Lappaconitine with β-Cyclodextrin

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The inclusion complex of lappaconitine (Lap) with β-cyclodextrin (β-CD) has been studied by the differential scanning calorimetry (DSC) and 1H-NMR, 2D-NMR spectroscopy.The structure of the complex has been deduced.``

  13. Measuring thermal conductivity of powders with differential scanning calorimetry

    OpenAIRE

    Pujula, Miquel; Sánchez-Rodríguez, Daniel; López-Olmedo, Joan Pere; Farjas Silva, Jordi; Roura Grabulosa, Pere

    2016-01-01

    This paper simplifies a recently proposed method for measuring the thermal conductivity of powders using differential scanning calorimetry (DSC) (Sa´nchez-Rodríguez et al. in J Therm Anal Calorim 121:469-473, 2015). With this method, a crucible is filled with powder and a spherical metal reference is partially sunk into it. The thermal resistance between the metal and the crucible wall at the metal melting point is obtained from the DSC melting peak slope. In the simplified method outlined in...

  14. Thermodynamic investigations of nitroxoline sublimation by simultaneous DSC-FTIR method and isothermal TG analysis.

    Science.gov (United States)

    Gao, Gau-Yi; Lin, Shan-Yang

    2010-01-01

    To investigate the physicochemical characteristics, thermodynamics, possible sublimation process and kinetics of nitroxoline, differential scanning calorimetry (DSC), isothermal thermogravimetry (TG), and Fourier transform infrared (FTIR) microspectroscopy equipped with a micro hot-stage of DSC microscopy assembly (simultaneous DSC-FTIR method) were used. The DSC result indicates that nitroxoline exhibited a sharp endothermic peak at 182 degrees C with enthalpy of 103.1 J/g due to the melting point of nitroxoline. A sublimation behavior of nitroxoline was found from 129 degrees C by gradual weight loss in TG curve. However, the nonisothermal DSC-FTIR method reveals that the temperature at 95 degrees C was the onset temperature of nitroxoline sublimation. A significant difference between DSC-FTIR method and TG analysis suggests that the simultaneous DSC-FTIR method was more sensitive than that of the TG analysis to detect the beginning temperature of nitroxoline sublimation. The sublimation kinetics of nitroxoline determined by isothermal TG analysis evidenced that the zero-order kinetics was followed over the sublimation time. The sublimation enthalpy correction was also carried out by a group additivity approach for the estimation of heat capacity. The enthalpy of nitroxoline sublimation estimated was 86.14 KJ/mol at 298.15 K.

  15. 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.

  16. In Situ Stability of Substrate-Associated Cellulases Studied by DSC

    DEFF Research Database (Denmark)

    Borch, Kim; Cruys-Bagger, Nicolaj; Badino, Silke Flindt;

    2014-01-01

    This work shows that differential scanning calorimetry (DSC) can be used to monitor the stability of substrate-adsorbed cellulases during long-term hydrolysis of insoluble cellulose. Thermal transitions of adsorbed enzyme were measured regularly in subsets of a progressing hydrolysis, and the size....... There was no correlation between the intrinsic stability, specified by the transition temperature in the DSC, and the long-term stability derived from the peak area. The results are discussed with respect to the role of enzyme denaturation for the ubiquitous slowdown observed in the enzymatic hydrolysis of cellulose....

  17. Solid state and sub-cooled liquid vapour pressures of substituted dicarboxylic acids using Knudsen Effusion Mass Spectrometry (KEMS and Differential Scanning Calorimetry

    Directory of Open Access Journals (Sweden)

    A. M. Booth

    2010-02-01

    Full Text Available Solid state vapour pressures of a selection of substituted dicarboxylic acids have been measured using Knudsen Effusion Mass Spectrometry (KEMS. Enthalpies of fusion and melting points obtained using Differential Scanning Calorimetry (DSC were used to obtain sub-cooled liquid vapour pressures. They have been compared to estimation methods used on the E-AIM website. These methods are shown to poorly represent -OH groups in combination with COOH groups. Partitioning calculations have been performed to illustrate the impact of the different estimation methods on organic aerosol mass compared to the use of experimental data.

  18. Solid state and sub-cooled liquid vapour pressures of substituted dicarboxylic acids using Knudsen Effusion Mass Spectrometry (KEMS and Differential Scanning Calorimetry

    Directory of Open Access Journals (Sweden)

    A. M. Booth

    2010-05-01

    Full Text Available Solid state vapour pressures of a selection of atmospherically important substituted dicarboxylic acids have been measured using Knudsen Effusion Mass Spectrometry (KEMS over a range of 20 K (298–318 K. Enthalpies of fusion and melting points obtained using Differential Scanning Calorimetry (DSC were used to obtain sub-cooled liquid vapour pressures. They have been compared to estimation methods used on the E-AIM website. These methods are shown to poorly represent – OH groups in combination with COOH groups. Partitioning calculations have been performed to illustrate the impact of the different estimation methods on organic aerosol mass compared to the use of experimental data.

  19. Measurement and Model Validation of Nanofluid Specific Heat Capacity with Differential Scanning Calorimetry

    Directory of Open Access Journals (Sweden)

    Harry O'Hanley

    2012-01-01

    Full Text Available Nanofluids are being considered for heat transfer applications; therefore it is important to know their thermophysical properties accurately. In this paper we focused on nanofluid specific heat capacity. Currently, there exist two models to predict a nanofluid specific heat capacity as a function of nanoparticle concentration and material. Model I is a straight volume-weighted average; Model II is based on the assumption of thermal equilibrium between the particles and the surrounding fluid. These two models give significantly different predictions for a given system. Using differential scanning calorimetry (DSC, a robust experimental methodology for measuring the heat capacity of fluids, the specific heat capacities of water-based silica, alumina, and copper oxide nanofluids were measured. Nanoparticle concentrations were varied between 5 wt% and 50 wt%. Test results were found to be in excellent agreement with Model II, while the predictions of Model I deviated very significantly from the data. Therefore, Model II is recommended for nanofluids.

  20. 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.

  1. Insights into glass transition and relaxation behavior using temperature-modulated differential scanning calorimetry

    DEFF Research Database (Denmark)

    Guo, Xiaoju; Mauro, J.C.; Allan, D.C.;

    Temperature-modulated differential scanning calorimetry (TMDSC) is based on conventional DSC but with a sinusoidally modulated temperature path. Our simulations of TMDSC signals prove that the frequency correction of non-reversing heat flow can give a master curve within a certain range of freque......Temperature-modulated differential scanning calorimetry (TMDSC) is based on conventional DSC but with a sinusoidally modulated temperature path. Our simulations of TMDSC signals prove that the frequency correction of non-reversing heat flow can give a master curve within a certain range...

  2. Dual-readout Calorimetry

    OpenAIRE

    Akchurin, N.; Bedeschi, F.; Cardini, A.; Cascella, M.; Cei, F.; Pedis, D.; Fracchia, S.; Franchino, S.; Fraternali, M.; Gaudio, G.; P. Genova; Hauptman, J.; La Rotonda, L.; Lee, S.; Livan, M.(INFN Sezione di Pavia, Pavia, Italy)

    2013-01-01

    The RD52 Project at CERN is a pure instrumentation experiment whose goal is to understand 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 n...

  3. 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.

  4. Differential scanning calorimetry and fluorescence study of lactoperoxidase as a function of guanidinium-HCl, urea, and pH.

    Science.gov (United States)

    Zelent, Bogumil; Sharp, Kim A; Vanderkooi, Jane M

    2010-07-01

    The stability of bovine lactoperoxidase to denaturation by guanidinium-HCl, urea, or high temperature was examined by differential scanning calorimetry (DSC) and tryptophan fluorescence. The calorimetric scans were observed to be dependent on the heating scan rate, indicating that lactoperoxidase stability at temperatures near Tm is controlled by kinetics. The values for the thermal transition, Tm, at slow heating scan rate were 66.8, 61.1, and 47.2 degrees C in the presence of 0.5, 1, and 2 M guanidinium-HCl, respectively. The extrapolated value for Tm in the absence of guanidinium-HCl is 73.7 degrees C, compared with 70.2 degrees C obtained by experiment; a lower experimental value without a denaturant is consistent with distortion of the thermal profile due to aggregation or other irreversible phenomenon. Values for the heat capacity, Cp, at Tm and Ea for the thermal transition decrease under conditions where Tm is lowered. At a given concentration, urea is less effective than guanidinium-HCl in reducing Tm, but urea reduces Cp relatively more. Both fluorescence and DSC indicate that thermally denatured protein is not random coil. A change in fluorescence around 35 degrees C, which was previously reported for EPR and CD measurements (Boscolo et al. Biochim. Biophys. Acta 1774 (2007) 1164-1172), is not seen by calorimetry, suggesting that a local and not a global change in protein conformation produces this fluorescence change.

  5. Changes of multi-scale structure during mimicked DSC heating reveal the nature of starch gelatinization

    Science.gov (United States)

    Wang, Shujun; Zhang, Xiu; Wang, Shuo; Copeland, Les

    2016-06-01

    A thorough understanding of starch gelatinization is extremely important for precise control of starch functional properties for food processing and human nutrition. Here we reveal the molecular mechanism of starch gelatinization by differential scanning calorimetry (DSC) in conjunction with a protocol using the rapid viscosity analyzer (RVA) to generate material for analysis under conditions that simulated the DSC heating profiles. The results from DSC, FTIR, Raman, X-ray diffraction and small angle X-ray scattering (SAXS) analyses all showed that residual structural order remained in starch that was heated to the DSC endotherm end temperature in starch:water mixtures of 0.5 to 4:1 (v/w). We conclude from this study that the DSC endotherm of starch at a water:starch ratio of 2 to 4 (v/w) does not represent complete starch gelatinization. The DSC endotherm of starch involves not only the water uptake and swelling of amorphous regions, but also the melting of starch crystallites.

  6. Changes of multi-scale structure during mimicked DSC heating reveal the nature of starch gelatinization.

    Science.gov (United States)

    Wang, Shujun; Zhang, Xiu; Wang, Shuo; Copeland, Les

    2016-06-20

    A thorough understanding of starch gelatinization is extremely important for precise control of starch functional properties for food processing and human nutrition. Here we reveal the molecular mechanism of starch gelatinization by differential scanning calorimetry (DSC) in conjunction with a protocol using the rapid viscosity analyzer (RVA) to generate material for analysis under conditions that simulated the DSC heating profiles. The results from DSC, FTIR, Raman, X-ray diffraction and small angle X-ray scattering (SAXS) analyses all showed that residual structural order remained in starch that was heated to the DSC endotherm end temperature in starch:water mixtures of 0.5 to 4:1 (v/w). We conclude from this study that the DSC endotherm of starch at a water:starch ratio of 2 to 4 (v/w) does not represent complete starch gelatinization. The DSC endotherm of starch involves not only the water uptake and swelling of amorphous regions, but also the melting of starch crystallites.

  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. Differential scanning calorimetry: An invaluable tool for a detailed thermodynamic characterization of macromolecules and their interactions

    Directory of Open Access Journals (Sweden)

    Michael H Chiu

    2011-01-01

    Full Text Available Differential Scanning Calorimetry (DSC is a highly sensitive technique to study the thermotropic properties of many different biological macromolecules and extracts. Since its early development, DSC has been applied to the pharmaceutical field with excipient studies and DNA drugs. In recent times, more attention has been applied to lipid-based drug delivery systems and drug interactions with biomimetic membranes. Highly reproducible phase transitions have been used to determine values, such as, the type of binding interaction, purity, stability, and release from a drug delivery mechanism. This review focuses on the use of DSC for biochemical and pharmaceutical applications.

  10. Calorimetry Task Force Report

    CERN Document Server

    Abdullin, Salavat; Banerjee, Sunanda; Beauceron, Stephanie; Beaudette, Florian; Bhatti, Anwar; Chlebana, Frank; Cossutti, Fabio; Hirschauer, James; Ivanchenko, V; Jang, Dong Wook; Jun, Soon Yung; Kunori, Shuichi; Kroeger, Rob; Liu, Yanwen; Moeller, Anthony; Paulini, Manfred; Piperov, Stefan; Rahmat, Rahmat; Rovelli, Chiara; Safronov, Grigory; Sharma, Seema; Spiropulu, Maria; Yetkin, Taylan

    2010-01-01

    In this note we summarize the progress made by the calorimeter simulation task force (CaloTF) over the past year. The CaloTF was established in February 2008 in order to understand and reconcile the discrepancies observed between the CMS calorimetry simulation and test beam data recorded during 2004 and 2006. The simulation has been significantly improved by using a newer version of Geant4 and an improved physics list for the full CMS detector simulation. Simulation times have been reduced by introducing flexible parameterizations to describe showering in the calorimeter (using a Gflash-like approach) which have been tuned to the test beam data.

  11. 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...

  12. Applications of high pressure differential scanning calorimetry to aviation fuel thermal stability research

    Science.gov (United States)

    Neveu, M. C.; Stocker, D. P.

    1985-01-01

    High pressure differential scanning calorimetry (DSC) was studied as an alternate method for performing high temperature fuel thermal stability research. The DSC was used to measure the heat of reaction versus temperature of a fuel sample heated at a programmed rate in an oxygen pressurized cell. Pure hydrocarbons and model fuels were studied using typical DSC operating conditions of 600 psig of oxygen and a temperature range from ambient to 500 C. The DSC oxidation onset temperature was determined and was used to rate the fuels on thermal stability. Kinetic rate constants were determined for the global initial oxidation reaction. Fuel deposit formation is measured, and the high temperature volatility of some tetralin deposits is studied by thermogravimetric analysis. Gas chromatography and mass spectrometry are used to study the chemical composition of some DSC stressed fuels.

  13. Starch transitions of different gluten free flour doughs determined by dynamic thermal mechanical analysis and differential scanning calorimetry.

    Science.gov (United States)

    Moreira, R; Chenlo, F; Arufe, S

    2015-01-01

    Gluten-free flour doughs (three from different maize varieties and one from chestnut fruit) processed at the same consistency level (1.10 ± 0.07 N m) with different water absorption were used to determine the starch transitions by means of two different experimental techniques, differential scanning calorimetry (DSC) and dynamic thermal mechanical analysis (DMTA). The ranges of temperatures of gelatinization (G), amylopectin melting (M1), amylose-lipid complexes melting (M2) and amylose melting (M3) for all tested flour doughs were determined by both experimental techniques with acceptable agreement between them. The starch transitions in DMTA were determined by means of the elastic modulus (G, M1 and M2) or damping factor (G, M3) evolution with temperature. The temperatures and enthalpies of the transitions depended on water content, the nature and characteristics (mainly damaged starch) of the starch and the presence of other compounds (mainly lipid and sugars) in the flour doughs.

  14. 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

    The hydration properties of proline are studied by differential scanning calorimetry (DSC) in aqueous solutions during freezing to -60 degrees C and subsequent heating to +20 degrees C. The concentration of proline in the freeze concentrated solution was estimated to approximately 50 wt% (w/w) in...

  15. On the Frequency Correction in Temperature-Modulated Differential Scanning Calorimetry of Glass Transition

    DEFF Research Database (Denmark)

    Guo, Xiaoju; Mauro, J.C.; Allan, D.C.;

    2012-01-01

    Temperature-modulated differential scanning calorimetry (TMDSC) is based on conventional DSC but with a sinusoidally modulated temperature path. Simulations of TMDSC signals were performed for Corning EAGLE XG® glass over a wide range of modulation frequencies. Our results reveal that the frequen...

  16. 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/.

  17. 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)

  18. Fast-Scan DSC and its role in pharmaceutical physical form characterisation and selection.

    Science.gov (United States)

    Ford, James L; Mann, Timothy E

    2012-04-01

    Conventional rate Differential Scanning Calorimetry (DSC) has been used for many years as a tool in the analysis of pharmaceutical materials. In recent years an extension of the technique to include fast heating and cooling rates has become more prevalent. Broadly termed Fast-Scan DSC, this review examines the current applications of this technique to the characterisation and selection of pharmaceutical materials. Its increasing use encompasses the characterisation of amorphousness in crystalline materials, the characterisation of polymorphs and polymorphic transitions, the solubility of drugs in polymers, and characterisation of dosage forms. Notwithstanding the advantages of analytical speed in analytical turnover, the review emphasises the advantages of Fast-Scan DSC in its sensitivity which allows the separation of overlapping thermal events, the reduction it provides in degradation during the scanning process and its role in determining solubility in waxy and polymeric based systems. A comparison of the uses of Fast-Scan DSC to modulated DSC techniques and localised thermal analysis is also given.

  19. Evaluation of integrated Raman-DSC technology in early pharmaceutical development: characterization of polymorphic systems.

    Science.gov (United States)

    Huang, Jun; Dali, Manisha

    2013-12-01

    Differential Scanning Calorimetry and Raman spectroscopy are both powerful tools used heavily in pharmaceutical development. For many studies such as polymorph characterization these two techniques are complimentary and provide data on different yet important aspects of material properties when combined together. In this work we describe an integrated Raman-DSC technology that simultaneously generates both DSC thermogram and Raman spectra of the pharmaceutical material being studied. The integrated system consists of a DSC with a Raman fiber optic probe inserted right on top of the sample furnace. The technology integrates synchronized Raman acquisition into DSC scan, enabling collection of molecular and structural information coupled with observation of thermal events. We first establish the technology by optimizing the instrumental set-up that offers relatively high-quality results for simultaneous DSC and Raman data collection. We then demonstrate the application of the technology by studying the polymorphs of d-mannitol, a common pharmaceutical excipient and BMS-A, an investigational drug candidate that exhibits multiple coexisting polymorphs. In both cases, the Raman-DSC technology was able to provide valuable information on the process of phase change and polymorph identification. Although similar information may be obtained by using various characterization techniques together, the integrated Raman-DSC indicated special advantages for industrial development such as high efficiency, material sparing and comprehensive data analysis. Moreover the technology provides an alternative to better correlate real-time phase behavior to molecular understanding. The technology thus has the potential to be used for Process Analytical Technology (PAT) purpose.

  20. 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.

  1. 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

  2. Application of calorimetry and thermal analysis to determine the liquid range and the environmental toxicity of ionic liquids

    OpenAIRE

    Parajó Vieito, Juan José

    2016-01-01

    This PhD Thesis is focused on the applicability of thermal analysis and calorimetry techniques to determine phase transitions (through Differential Scanning Calorimetry (DSC)), thermal stability (measured by Thermogravimetric Analysis (TGA)) and ecotoxicity (trhough Thermal Activity Monitor (TAM) and seed germination response tests) of ionic liquids (ILs) to be used as lubricants and/or absorbents in heat pumps. The studied compounds are based on different anions (imide, triflate, sulphonate,...

  3. Differential scanning calorimetry of blood plasma for clinical diagnosis and monitoring.

    Science.gov (United States)

    Garbett, Nichola C; Mekmaysy, Chongkham S; Helm, C William; Jenson, A Bennett; Chaires, Jonathan B

    2009-06-01

    Differential scanning calorimetry (DSC) provides a useful method to study the unfractionated plasma proteome. Plasma from healthy individuals yields a reproducible signature thermogram which results from the weighted sum of the thermal denaturation of the most abundant plasma proteins. Further investigation of the thermogram for healthy individuals showed it to be sensitive to ethnicity and gender. DSC analysis of plasma from diseased individuals revealed significant changes in the thermogram which are suggested to result not from changes in the concentration of the major plasma proteins but from interactions of small molecules or peptides with these proteins. Closer examination of the diseased thermograms showed a thermogram characteristic of each disease. For cervical cancer, the DSC method yields a progressively shifted thermogram as the disease advances from pre-invasive conditions to late stage cancer. Our application of the DSC method has provided a potential tool for the early diagnosis, monitoring and screening of cancer patients.

  4. DSC、MDSC测定物质比热容的比较%Comparison of differential scanning calorimetry and modulated differential scanning calorimetry in measurement of specific heat capacities

    Institute of Scientific and Technical Information of China (English)

    鲁红; 冯大春; 杨继佑

    2011-01-01

    实验用TA公司具有DSC、MDSC两种模式、具备先进Tzero技术的热流型DSCQ200热分析仪测定物质的比热容.对如何运用传统方法及调制方法测定物质的比热容进行了详细阐述;以氯化钾、苯甲酸、去离子水为测试样,对两种方法所得实验结果进行了分析比较.%The specific heat capacities of potassium choride, benzoic acid and deionized water samples were measured by DSCQ 200 tbermal analyzer in two different method (differential scanning calorimetry. DSC, and modulated differential scanning calorimetry. MDSC), The results obtained by two methods are compared.The questions in the application of DSC and MDSC are discussed in detail.

  5. 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.

  6. The effects of urea and n-propanol on collagen denaturation: using DSC, circular dicroism and viscosity

    Energy Technology Data Exchange (ETDEWEB)

    Usha, R.; Ramasami, T

    2004-01-30

    The effect of urea and n-propanol on circular dichroism (CD) and viscosity of purified type1 collagen solution at various temperatures and differential scanning calorimetry (DSC) of rat-tail tendon (RTT) collagen fibre have been studied. CD reveals a spectrum with a positive peak at around 220 nm and a negative peak at 200 nm characteristics of collagen triple helix. The molar ellipticity decreases as the concentration of urea increases up to particular concentration (collagen solution treated with 265 {mu}M of urea) and after that it increases (collagen solution treated with 500 {mu}M of urea). There is a linear decrease in molar ellipticity as the concentration of n-propanol increases. Denaturation temperature of urea and n-propanol treated with purified collagen solution has been studied using viscosity method. Additives such as urea and n-propanol decrease the thermal stability of collagen triple helix in solution and in RTT collagen fibre. Thermal helix to coil transition of urea and n-propanol treated collagen depends on the degree of hydration and the concentration of these additives. Thermodynamic parameters such as the peak temperature, enthalpy of activation, and energy of activation for collagen-gelatin transition for native, urea and n-propanol treated RTT collagen fibre has been calculated using DSC. The change in the thermodynamic parameters has been observed for native, urea and n-propanol treated RTT collagen fibres. The experimental results show that the change in the water structure, dehydration and desolvation induced by different additives such as urea and n-propanol on RTT may vary with the type of denaturation.

  7. Thermo-kinetic prediction of metastable and stable phase precipitation in Al–Zn–Mg series aluminium alloys during non-isothermal DSC analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lang, Peter, E-mail: pl404@cam.ac.uk [Department of Materials Science and Metallurgy, University of Cambridge, Charles Babbage Road 27, Cambridge CB3 0FS (United Kingdom); Wojcik, Tomasz [Institute of Materials Science and Technology, Vienna University of Technology, Favoritenstraße 9-11, Vienna 1040 (Austria); Povoden-Karadeniz, Erwin [Institute of Materials Science and Technology, Vienna University of Technology, Favoritenstraße 9-11, Vienna 1040 (Austria); Christian Doppler Laboratory “Early Stages of Precipitation”, Institute of Materials Science and Technology, Vienna University of Technology, Favoritenstraße 9-11, Vienna 1040 (Austria); Falahati, Ahmad [Institute of Materials Science and Technology, Vienna University of Technology, Favoritenstraße 9-11, Vienna 1040 (Austria); Kozeschnik, Ernst [Institute of Materials Science and Technology, Vienna University of Technology, Favoritenstraße 9-11, Vienna 1040 (Austria); Christian Doppler Laboratory “Early Stages of Precipitation”, Institute of Materials Science and Technology, Vienna University of Technology, Favoritenstraße 9-11, Vienna 1040 (Austria)

    2014-10-01

    Highlights: • Comparison of laboratory Al–Zn–Mg alloy to industrial Al 7xxx series. • Heat flow evolution during non-isothermal DSC analysis is calculated. • TEM investigations of laboratory Al–Zn–Mg alloy at three pronounced temperatures. • Simulation and modelling of precipitation sequence. • Calculation and prediction of heat flow curves of Al 7xxx series. - Abstract: The technological properties of heat treatable Al–Zn–Mg alloys originate in the morphology and distribution of metastable particles. Starting from the solution-annealed condition, this paper describes the precipitate evolution during non-isothermal temperature changes, namely continuous heating differential scanning calorimetry (DSC) analysis. The distribution and the morphology of the metastable and stable precipitates and the heat flow accompanying the precipitation process is investigated experimentally and calculated by numerical thermo-kinetic simulations. The computer simulation results of the sizes and distributions are confirmed by transmission electron microscopy (TEM). The theoretical background and the results of the investigations are discussed.

  8. DSC study on the undercooling of droplet solidification of metal melt

    Institute of Scientific and Technical Information of China (English)

    GUAN Wanbing; GAO Yulai; ZHAI Qijie; XU Kuangdi

    2005-01-01

    In this paper, the influence of cooling rate on the undercooling of droplet solidification of metal melt has been investigated by employing the differential scanning calorimetry (DSC) method. The effect of cooling rate on the undercooling as well as its change tendency is analyzed theoretically. It is shown that the undercooling degree increases whereas the change rate of undercooling decreases with increasing cooling rate. Moreover, the change tendency approaches zero when the cooling rate exceedingly increased, indicating that an extremum of undercooling exists with increasing cooling rate.

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

    Directory of Open Access Journals (Sweden)

    J. Piątkowski

    2008-12-01

    Full Text Available The investigations of phase transformations described in this study were carried out on hypoeutectic alloys from the Al-Si system (AlSi3, AlSi6 and AlSi9 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 scanning calorimeter. Applying the lever rule, the phase composition of the examined silumins was calculated and compared with the results of DSC calorimetry, obtaining a good correlation of the results.

  10. Laser-high-speed-DSC: Process-oriented Thermal Analysis of PA 12 in Selective Laser Sintering

    Science.gov (United States)

    Lanzl, Lydia; Wudy, Katrin; Drexler, Maximilian; Drummer, Dietmar

    In the Selective Laser Sintering process very high heating rates occur due to the melting of the material by a laser. Extreme scanning rates could not be measured by conventional thermal analysis methods, since typical heating rates for DSC (differential scanning calorimetry) are between 5-20K min-1. By using a Laser-High-Speed-DSC, a self-developed combination of a Flash-DSC and a fitted laser head, the sample is directly heated by a CO2 laser like in the SLS process. These experiments allow a process-oriented thermal analyzation of the material. In this paper, the set-up and function of this new measuring method is introduced. Furthermore, the reliability of the measurements is evaluated by statistical design of experiment methods. By using this new measuring method, the time-dependent melting behavior of the polymer can be analyzed. Moreover, sample temperatures and heating rates dependent on laser exposure times can be quantified.

  11. Statistical analysis of plasma thermograms measured by differential scanning calorimetry.

    Science.gov (United States)

    Fish, Daniel J; Brewood, Greg P; Kim, Jong Sung; Garbett, Nichola C; Chaires, Jonathan B; Benight, Albert S

    2010-11-01

    Melting curves of human plasma measured by differential scanning calorimetry (DSC), known as thermograms, have the potential to markedly impact diagnosis of human diseases. A general statistical methodology is developed to analyze and classify DSC thermograms to analyze and classify thermograms. Analysis of an acquired thermogram involves comparison with a database of empirical reference thermograms from clinically characterized diseases. Two parameters, a distance metric, P, and correlation coefficient, r, are combined to produce a 'similarity metric,' ρ, which can be used to classify unknown thermograms into pre-characterized categories. Simulated thermograms known to lie within or fall outside of the 90% quantile range around a median reference are also analyzed. Results verify the utility of the methods and establish the apparent dynamic range of the metric ρ. Methods are then applied to data obtained from a collection of plasma samples from patients clinically diagnosed with SLE (lupus). High correspondence is found between curve shapes and values of the metric ρ. In a final application, an elementary classification rule is implemented to successfully analyze and classify unlabeled thermograms. These methods constitute a set of powerful yet easy to implement tools for quantitative classification, analysis and interpretation of DSC plasma melting curves.

  12. Calorimetric thermobarometry of experimentally shocked quartz

    Science.gov (United States)

    Ocker, Katherine D.; Gooding, James L.; Hoerz, Friedrich

    1994-01-01

    Structural damage in experimentally shock-metamorphosed, granular quartz is quantitatively measurable by differential scanning calorimetry (DSC). Shock-induced loss of crystallinity is witnessed by disappearance of the alpha/beta phase transformation and evolution of a broad endoenthalpic strain peak at 650-900 K. The strain-energy peak grows rapidly at less than 10 GPa but declines with increasing shock pressure; it approaches zero at 32 GPa where vitrification is extensive. Effects of grain size and post-shock thermal history must be better understood before calorimetric thermobarometry of naturally shocked samples becomes possible.

  13. 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 grap......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...

  14. 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

  15. 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.

  16. DSC “peak temperature” versus “maximum slope temperature” in determining TSSD temperature

    Science.gov (United States)

    Khatamian, D.

    2010-10-01

    One of the concerns of the nuclear industry is the deleterious effect of hydrogen on the structural integrity of the reactor core components due to delayed hydride cracking (DHC). The DHC process occurs when hydrogen concentration exceeds the terminal solid solubility (TSS) in the component. Thus, the accurate knowledge of TSS is necessary to predict the lifetime of the components. Differential scanning calorimetry (DSC) is normally used to measure the hydrogen TSS in zirconium alloys. There is a measurable change in the amount of heat absorbed by the specimen when the hydrides dissolve. The hydride dissolution process does not exhibit a well-defined "sharp" change in the heat-flow signal at the transition temperature. A typical DSC heat-flow curve for hydride dissolution has three definite features; "peak temperature" (PT), "maximum slope temperature" (MST) and "completion temperature". The present investigation aims to identify the part of the heat-flow signal that closely corresponds to the TSS temperature for hydride dissolution ( TTSSD). Coupons were cut from a Zr-2.5Nb specimen, which had been previously hydrided using an electrolytic cell to create a surface hydride layer of ˜20 μm thick on all sides of the specimen. The coupons were then annealed isothermally at various temperatures to establish the TTSSD under equilibrium conditions. Subsequently the hydride layer was removed and the coupons were analyzed for TSSD temperature using DSC. The PT and MST for each DSC run were determined and compared to the annealing temperature of the coupon. The results show that the annealing temperature (the equilibrium TTSSD) is much closer to the DSC PT than any other feature of the heat-flow curve.

  17. 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 ...

  18. Calorimetry fundamentals, instrumentation and applications

    CERN Document Server

    Sarge, Stefan M; Hemminger, Wolfgang

    2014-01-01

    Clearly divided into three parts, this practical book begins by dealing with all fundamental aspects of calorimetry. The second part looks at the equipment used and new developments. The third and final section provides measurement guidelines in order to obtain the best results. The result is optimized knowledge for users of this technique, supplemented with practical tips and tricks.

  19. New methodology developed for the differential scanning calorimetry analysis of polymeric matrixes incorporating phase change materials

    Science.gov (United States)

    Barreneche, Camila; Solé, Aran; Miró, Laia; Martorell, Ingrid; Inés Fernández, A.; Cabeza, Luisa F.

    2012-08-01

    Nowadays, thermal comfort needs in buildings have led to an increase in energy consumption of the residential and service sectors. For this reason, thermal energy storage is shown as an alternative to achieve reduction of this high consumption. Phase change materials (PCM) have been studied to store energy due to their high storage capacity. A polymeric material capable of macroencapsulating PCM was developed by the authors of this paper. However, difficulties were found while measuring the thermal properties of these materials by differential scanning calorimetry (DSC). The polymeric matrix interferes in the detection of PCM properties by DSC. To remove this interfering effect, a new methodology which replaces the conventional empty crucible used as a reference in the DSC analysis by crucibles composed of the polymeric matrix was developed. Thus, a clear signal from the PCM is obtained by subtracting the new full crucible signal from the sample signal.

  20. Application of solution calorimetry in pharmaceutical and biopharmaceutical research.

    Science.gov (United States)

    Royall, P G; Gaisford, S

    2005-06-01

    In solution calorimetry the heat of solution (Delta(sol)H) is recorded as a solute (usually a solid) dissolves in an excess of solvent. Such measurements are valuable during all the phases of pharmaceutical formulation and the number of applications of the technique is growing. For instance, solution calorimetry is extremely useful during preformulation for the detection and quantification of polymorphs, degrees of crystallinity and percent amorphous content; knowledge of all of these parameters is essential in order to exert control over the manufacture and subsequent performance of a solid pharmaceutical. Careful experimental design and data interpretation also allows the measurement of the enthalpy of transfer (Delta(trans)H) of a solute between two phases. Because solution calorimetry does not require optically transparent solutions, and can be used to study cloudy or turbid solutions or suspensions directly, measurement of Delta(trans)H affords the opportunity to study the partitioning of drugs into, and across, biological membranes. It also allows the in-situ study of cellular systems. Furthermore, novel experimental methodologies have led to the increasing use of solution calorimetry to study a wider range of phenomena, such as the precipitation of drugs from supersaturated solutions or the formation of liposomes from phospholipid films. It is the purpose of this review to discuss some of these applications, in the context of pharmaceutical formulation and preformulation, and highlight some of the potential future areas where solution calorimetry might find applications.

  1. Thermodynamic Study of 8-Hydroxyquinoline by Adiabatic Calorimetry and Thermal Analysis

    Institute of Scientific and Technical Information of China (English)

    WANG Shao-Xu; TAN Zhi-Cheng; LI Yan-Sheng; TONG Bo; LI Ying; SHI Quan; ZHANG Jing-Nan

    2008-01-01

    A calorimetric study and thermal analysis for 8-hydroxyquinoline were performed.The low-temperature heat capacity of this compound was measured with a precise automated adiabatic calorimeter over the temperature range from 78 to 370 K.The melting point True,molar enthalpy △fusHm and molar entropy △fusSm of fusion of this sub-tively.The thermodynamic functions of the substance,such as molar enthalpy and entropy of fusion,and thermo-dynamic functions [Hr-H298.15] and [ST-S298.15] were derived from two polynomial equations of the experi-mental molar heat capacities against the reduced temperature fitted by the least square method.The melting tem-peratures for the sample and the absolutely pure compound have been obtained from fractional melting experiments to be 345.601 and 345.761 K,respectively,and the molar fraction purity of the sample was calculated to be 0.9978 according to the van't Hoff equation.The thermal stability of the compound was further investigated by differential scanning calorimetry(DSC).

  2. 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.

  3. Indirect calorimetry during incubation of hatching eggs

    NARCIS (Netherlands)

    Brand, van den H.; Heetkamp, M.J.W.; Kemp, B.

    2015-01-01

    Indirect calorimetry can be used during incubation of avian eggs to monitor the quality of the incubation process, the development of the embryo and the utilization of nutrients. Indirect calorimetry has several benefits above direct calorimetry, particularly in hatching eggs. However, to obtain rel

  4. 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…

  5. 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.

  6. The use of differential scanning calorimetry for the purity verification of pharmaceutical reference standards.

    Science.gov (United States)

    Mathkar, S; Kumar, S; Bystol, A; Olawoore, K; Min, D; Markovich, R; Rustum, A

    2009-04-05

    Reference standards are routinely used in pharmaceutical industry to determine strength, content, and the quality of drug products, active pharmaceutical ingredients (API), preservatives, antioxidants and excipients. Traditionally, chromatographic techniques such as High Performance Liquid Chromatography (HPLC) and Gas Chromatography (GC) in conjunction with other analytical techniques have been used to determine the purity and strength of a specific lot of a compound for the purpose of qualifying the lot to use as a reference standard. The assigned purity of the reference standard for a wide variety of compounds can be verified using an absolute method such as Differential Scanning Calorimetry (DSC). In this paper, purity of 16 reference standards was determined by DSC and the results were then compared to the purity values that were obtained using HPLC and other analytical techniques. The results indicate that the purity obtained from DSC analysis is comparable to the chromatographic purity for organic compounds that are at least 98% pure. Use of DSC for purity determination is not appropriate if a compound lacks sharp melting point, decomposes in the defined temperature range or exhibits other thermal event(s) which interfere with the melting point of the compound. The use of DSC as an alternative and or complementary method to verify the purity of a compound as part of the pharmaceutical reference standard certification process is discussed.

  7. Differential scanning calorimetry as a tool for protein folding and stability.

    Science.gov (United States)

    Johnson, Christopher M

    2013-03-01

    Differential scanning calorimetry measures the heat capacity of states and the excess heat associated with transitions that can be induced by temperature change. The integral of the excess heat capacity is the enthalpy for this process. Despite this potentially intimidating sounding physical chemistry background, DSC has found almost universal application in studying biological macromolecules. In the case of proteins, DSC can be used to determine equilibrium thermodynamic stability and folding mechanism but can also be used in a more qualitative manner screening for thermal stability as an indicator for, ligand binding, pharmaceutical formulation or conditions conducive to crystal growth. DSC usually forms part of a wider biophysical characterisation of the biological system of interest and so the literature is diverse and difficult to categorise for the technique in isolation. This review therefore describes the potential uses of DSC in studying protein folding and stability, giving brief examples of applications from the recent literature. There have also been some interesting developments in the use of DSC to determine barrier heights for fast folding proteins and in studying complex protein mixtures such as human plasma that are considered in more detail.

  8. 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.

  9. Pressure perturbation calorimetry of unfolded proteins.

    Science.gov (United States)

    Tsamaloukas, Alekos D; Pyzocha, Neena K; Makhatadze, George I

    2010-12-16

    We report the application of pressure perturbation calorimetry (PPC) to study unfolded proteins. Using PPC we have measured the temperature dependence of the thermal expansion coefficient, α(T), in the unfolded state of apocytochrome C and reduced BPTI. We have shown that α(T) is a nonlinear function and decreases with increasing temperature. The decrease is most significant in the low (2-55 °C) temperature range. We have also tested an empirical additivity approach to predict α(T) of unfolded state from the amino acid sequence using α(T) values for individual amino acids. A comparison of the experimental and calculated functions shows a very good agreement, both in absolute values of α(T) and in its temperature dependence. Such an agreement suggests the applicability of using empirical calculations to predict α(T) of any unfolded protein.

  10. 更加完美索尼DSC-TX9C/DSC-WX5C魅力出击

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    DSC-TX9C和DSC-WX5C分别为一代经典大热机型DSC-TXTC和DSC—WX1的后继产品。延续Exmor RCMOS影像传感器所带来的强大功能,在设计细节和功能应用上均有大幅提升。

  11. 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.

  12. 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%).

  13. 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.

  14. FTIR and DSC studies of the thermal and photochemical stability of Balanites aegyptiaca oil (Toogga oil).

    Science.gov (United States)

    Gardette, Jean-Luc; Baba, Mohamed

    2013-01-01

    The oil extracted from the bean of Balanites aegyptiaca was characterized, and its photochemical and thermal stabilization were evaluated. The chemical composition was determined using gas chromatography (GC), revealing that the oil is very rich in unsaturated fatty acids (72% omega-6 and omega-9). The photochemical stability was assessed by subjecting it to artificially accelerated photo-aging and then examining the changes using infrared spectroscopy. The thermal stability was studied at six different temperatures ranging from 130 to 200°C and monitored in situ by differential scanning calorimetry (DSC). The kinetic parameters (EA and k) describing the thermal degradation of this oil were calculated. It has been shown that the antioxidants present in the oil delay the oxidation process (induction period). The degradation of the Toogga oil was compared with that of oleic and linoleic fatty acids. In addition, the degradation of the Toogga oil extracted with hexane was compared to that of the neat oil.

  15. Crystallization Kinetics of Lithium Aluminum Germanium Phosphate Glass by DSC Technique

    Institute of Scientific and Technical Information of China (English)

    HE Kun; WANG Yanhang; ZU Chengkui; LIU Yonghua; ZHAO Huifeng; HAN Bin; CHENG Jiang

    2012-01-01

    The crystallization kinetics of Li2O-Al2O3-GeO2-P2O5 (LAGP) glass fabricated via the conventional melt-quenching method was studied by differential scanning calorimetry (DSC) under nonisothermal condition at different heating rates.The activation energy of glass transition Eg is 634.4 kJ/mol,indicating that LAGP glass is easy to crystallize at an elevated temperature.The activation energy of crystallization Ec and Avrami index n obtained from Matusita's model are 442.01 kJ/mol and 1.7,respectively.The value of n reveals that bulk crystallization predominates slightly over surface crystallization during crystallization process.LAGP glass-ceramics after different heat treatments have the same crystalline phases determined as major phase LiGe2(PO4)3,with AlPO4 and GeO2 as their impurity phases.

  16. DSC and TA characteristics of the inoculated Al-Zn20 alloy

    Directory of Open Access Journals (Sweden)

    W.K. Krajewski

    2011-01-01

    Full Text Available The paper brings information about inoculation process of the sand-cast binary Al-20 wt% Zn (AlZn20 alloy, inoculated with Ticontaining grain-refiners, i.e. AlTi5B1, AlTi3C0.15 and (AlZn-Ti3 master alloys (MA. During the experiments thermal analyses (TAand differential scanning calorimetry (DSC were used. Macrostructure observations were performed using light microscopy (LM . On thebasis of the performed examinations it was found that all the MAs used in this work caused significant grain refinement, which initiates via a heterogeneous nucleation mode. The obtained structure fineness of the inoculated AlZn20 alloy should positively influence i ts ductility, which is of great importance for the practical application of this group of foundry alloys.

  17. Direct animal calorimetry, the underused gold standard for quantifying the fire of life.

    Science.gov (United States)

    Kaiyala, Karl J; Ramsay, Douglas S

    2011-03-01

    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 in animals with genetic or pharmacologically-induced alterations that dysregulate metabolic fuel partitioning and storage so as to promote obesity and/or diabetes. Contemporary obesity and diabetes research relies heavily on metabolically abnormal animals. Recent data implicating individual and group variation in the gut microbiome in obesity and diabetes raise important questions about transforming aerobic gas exchange into HP because 99% of gut bacteria are anaerobic and they outnumber eukaryotic cells in the body by ∼10-fold. Recent credible work in non-standard laboratory animals documents substantial errors in respirometry-based estimates of HP. Accordingly, it seems obvious that new research employing simultaneous direct and indirect calorimetry (total calorimetry) will be essential to validate respirometric MR phenotyping in existing and future pharmacological and genetic models of obesity and diabetes. We also detail the use of total calorimetry with simultaneous core temperature assessment as a model for studying homeostatic control in a variety of experimental situations, including acute and chronic drug administration. Finally, we offer some tips on performing direct calorimetry, both singly and in combination with indirect calorimetry and core temperature assessment.

  18. Mechanistic investigation of the interaction between bisquaternary antimicrobial agents and phospholipids by liquid secondary ion mass spectrometry and differential scanning calorimetry.

    Science.gov (United States)

    Pashynskaya, V A; Kosevich, M V; Gömöry, A; Vashchenko, O V; Lisetski, L N

    2002-01-01

    Mechanisms of interaction between the antimicrobial drugs decamethoxinum and aethonium, which are based on bisquaternary ammonium compounds, and a phospholipid component of biological membranes, dipalmitoylphosphatidylcholine, were studied by means of liquid secondary ion mass spectrometry (LSIMS) and differential scanning calorimetry (DSC). Supramolecular complexes of the drugs with this phospholipid were recorded under secondary ion mass spectrometric conditions. The dependence of the structures of these complexes on structural parameters of the dications of the bisquaternary ammonium compounds was demonstrated. Tandem mass spectrometric investigations of the metastable decay of doubly charged ions of decamethoxinum and aethonium complexes with dipalmitoylphosphatidylcholine allowed estimation of structural parameters of these complexes in the gas phase. Interactions of decamethoxinum and aethonium with model membrane assemblies built from hydrated dipalmitoylphosphatidylcholine were studied using DSC. It was shown that while both drugs can interact with model membranes, the mechanisms of such interactions for decamethoxinum and aethonium differ. The correlation between the nature of these interactions and structural and electronic parameters of the dications of the two bisquaternary agents is discussed. Interpretation of combined mass spectrometric and calorimetric experimental data led to proposals that the molecular mechanisms of antimicrobial action of bisquaternary ammonium compounds are related to their effect on the membrane phospholipid components of microbial cells.

  19. DSC and universal bit-level combining for HARQ systems

    Directory of Open Access Journals (Sweden)

    Lv Tiejun

    2011-01-01

    Full Text Available Abstract This paper proposes a Dempster -Shafer theory based combining scheme for single-input single-output (SISO systems with hybrid automatic retransmission request (HARQ, referred to as DSC, in which two methods for soft information calculations are developed for equiprobable (EP and non-equiprobable (NEP sources, respectively. One is based on the distance from the received signal to the decision candidate set consisting of adjacent constellation points when the source bits are equiprobable, and the corresponding DSC is regarded as DSC-D. The other is based on the posterior probability of the transmitted signals when the priori probability for the NEP source bits is available, and the corresponding DSC is regarded as DSC-APP. For the diverse EP and NEP source cases, both DSCD and DSC-APP are superior to maximal ratio combining, the so-called optimal combining scheme for SISO systems. Moreover, the robustness of the proposed DSC is illustrated by the simulations performed in Rayleigh channel and AWGN channel, respectively. The results show that the proposed DSC is insensitive to and especially applicable to the fading channels. In addition, a DS detection-aided bit-level DS combining scheme is proposed for multiple-input multiple-output--HARQ systems. The bit-level DS combining is deduced to be a universal scheme, and the traditional log-likelihood-ratio combining is a special case when the likelihood probability is used as bit-level soft information.

  20. 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.

  1. 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 ...

  2. Recent development of material calorimetry%材料量热学的发展现状

    Institute of Scientific and Technical Information of China (English)

    孙玉霞; 李荣德

    2000-01-01

    材料量热学是测量材料变化过程中与热有关的各种物理量(如热焓、熵值等)变化规律的一门学科,分析了国内外材料量热学的发展状况,尤其是对材料量热学中的热分析技术进行了论述,对热分析方法中的差热分析方法(DTA)和差示扫描量热法(DSC)的应用情况做了分析和展望.%Material calorimetry is a subject that measures the changing laws of physical quantities such as enthalpy and entropy that are related to thermal. Recent development of material calorimetry at home and abroad has been reviewed and especially Thermal Analysis (fA) in calorimetric methods has been discussed in the paper. Differential Thermal Analysis (DTA) and Differential Scanning Calorimetry (DSC) in thermal analysis have been analyzed in derail. Moreover, several suggestions have been put forward in the end.

  3. Application of chemometric methods to differential scanning calorimeter (DSC) to estimate nimodipine polymorphs from cosolvent system.

    Science.gov (United States)

    Siddiqui, Akhtar; Rahman, Ziyaur; Khan, Mansoor A

    2015-06-01

    The focus of this study was to evaluate the applicability of chemometrics to differential scanning calorimetry data (DSC) to evaluate nimodipine polymorphs. Multivariate calibration models were built using DSC data from known mixtures of the nimodipine modification. The linear baseline correction treatment of data was used to reduce dispersion in thermograms. Principal component analysis of the treated and untreated data explained 96% and 89% of the data variability, respectively. Score and loading plots correlated variability between samples with change in proportion of nimodipine modifications. The R(2) for principal component regression (PCR) and partial lease square regression (PLS) were found to be 0.91 and 0.92. The root mean square of standard error of the treated samples for calibration and validation in PCR and PLS was found to be lower than the untreated sample. These models were applied to samples recrystallized from a cosolvent system, which indicated different proportion of modifications in the mixtures than those obtained by placing samples under different storage conditions. The model was able to predict the nimodipine modifications with known margin of error. Therefore, these models can be used as a quality control tool to expediently determine the nimodipine modification in an unknown mixture.

  4. Multivariate statistical analysis treatment of DSC thermal properties for animal fat adulteration.

    Science.gov (United States)

    Dahimi, Omar; Rahim, Alina Abdul; Abdulkarim, S M; Hassan, Mohd Sukri; Hashari, Shazamawati B T Zam; Mashitoh, A Siti; Saadi, Sami

    2014-09-01

    The adulteration of edible fats is a kind of fraud that impairs the physical and chemical features of the original lipid materials. It has been detected in various food, pharmaceutical and cosmeceutical products. Differential scanning calorimetry (DSC) is the robust thermo-analytical machine that permits to fingerprint the primary crystallisation of triacylglycerols (TAGs) molecules and their transition behaviours. The aims of this study was to assess the cross-contamination caused by lard concentration of 0.5-5% in the mixture systems containing beef tallow (BT) and chicken fat (CF) separately. TAGs species of pure and adulterated lipids in relation to their crystallisation and melting parameters were studied using principal components analysis (PCA). The results showed that by using the heating profiles the discrimination of LD from BT and CF was very clear even at low dose of less than 1%. Same observation was depicted from the crystallisation profiles of BT adulterated by LD doses ranging from 0.1% to 1% and from 2% to 5%, respectively. Furthermore, CF adulterated with LD did not exhibit clear changes on its crystallisation profiles. Consequently, DSC coupled with PCA is one of the techniques that might use to monitor and differentiate the minimum adulteration levels caused by LD in different animal fats.

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

    Science.gov (United States)

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

    2014-09-15

    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 CO 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.

  6. Thermal properties of poly(ethylene oxide)/lauric acid blends. A SSA-DSC study

    Energy Technology Data Exchange (ETDEWEB)

    Pielichowski, Krzysztof; Flejtuch, Kinga [Department of Chemistry and Technology of Polymers, Cracow University of Technology, ul. Warszawska 24, 31-155 Krakow (Poland)

    2006-03-15

    A series of poly(ethylene oxide) (PEO)/lauric acid blends with different compositions has been prepared and characterised by differential scanning calorimetry (DSC) in dynamic mode. It has been found that the enthalpy of melting and crystallisation reaches its highest value for PEO/lauric acid blend (1:1, w/w) which makes this system a promising candidate for thermal energy storage applications. Further studies by step-scan alternating (SSA)-DSC revealed that an increase of the temperature step causes that the average total heating rate is also increasing and the heat flow is characterised by higher values. Reversing component of the heat flow during melting reaches lowest values at highest step (step=1{sup o}) when the re-crystallisation of PEO is hindered. An increase of step generally leads to an increase of the number of non-equilibrium effects and facilitates the activation of kinetic non-reversing processes, hindering the overall crystallisation of PEO. For lauric acid, due to facile crystallisation and self-association, formation of ordered regular structures takes place faster and is influenced by non-reversing processes in higher proportion. (author)

  7. 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.)

  8. 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 (ɛ″) and conductivity (σ) values after the addition of GS. The ɛ″ 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.

  9. 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

  10. Real-time monitoring of the setting reaction of brushite-forming cement using isothermal differential scanning calorimetry.

    Science.gov (United States)

    Hofmann, M P; Nazhat, S N; Gbureck, U; Barralet, J E

    2006-11-01

    The setting behavior of a brushite-forming cement (beta-tricalcium phosphate/mono calcium monophosphate) was investigated using an indentation technique (the Gillmore needles method) and isothermal differential scanning calorimetry (DSC). The two objectives of the study were to investigate whether DSC could be used to real-time monitor a fast-setting calcium phosphate cement (CPC) and to determine if it is possible to correlate DSC results directly with conventional setting-time measurements. Best-fit linear correlation analysis revealed that both the initial and final setting time (T(i) and T(f)) measured by indentation were strongly correlated to the maximum heat flow measured with DSC. It seems therefore possible to predict the setting times, usually achieved with user dependent indentation methods, of this specific fast setting CPC on the basis of objective DSC measurements. The drawbacks of DSC, however, are its overall complexity and expense and the fact that only exothermal reactions can be investigated in comparison to the Gillmore needles method, furthermore, it is not possible to monitor the complete reaction as the first 2 or 3 min are lost due to sample preparation and apparatus set up.

  11. 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.

  12. Differential scanning calorimetry in life science: thermodynamics, stability, molecular recognition and application in drug design.

    Science.gov (United States)

    Bruylants, G; Wouters, J; Michaux, C

    2005-01-01

    All biological phenomena depend on molecular recognition, which is either intermolecular like in ligand binding to a macromolecule or intramolecular like in protein folding. As a result, understanding the relationship between the structure of proteins and the energetics of their stability and binding with others (bio)molecules is a very interesting point in biochemistry and biotechnology. It is essential to the engineering of stable proteins and to the structure-based design of pharmaceutical ligands. The parameter generally used to characterize the stability of a system (the folded and unfolded state of the protein for example) is the equilibrium constant (K) or the free energy (deltaG(o)), which is the sum of enthalpic (deltaH(o)) and entropic (deltaS(o)) terms. These parameters are temperature dependent through the heat capacity change (deltaCp). The thermodynamic parameters deltaH(o) and deltaCp can be derived from spectroscopic experiments, using the van't Hoff method, or measured directly using calorimetry. Along with isothermal titration calorimetry (ITC), differential scanning calorimetry (DSC) is a powerful method, less described than ITC, for measuring directly the thermodynamic parameters which characterize biomolecules. In this article, we summarize the principal thermodynamics parameters, describe the DSC approach and review some systems to which it has been applied. DSC is much used for the study of the stability and the folding of biomolecules, but it can also be applied in order to understand biomolecular interactions and can thus be an interesting technique in the process of drug design.

  13. Stability of some Cactaceae proteins based on fluorescence, circular dichroism, and differential scanning calorimetry measurements.

    Science.gov (United States)

    Gorinstein, S; Zemser, M; Vargas-Albores, F; Ochoa, J L; Paredes-Lopez, O; Scheler, C; Aksu, S; Salnikow, J

    1999-02-01

    Characterization of three cactus proteins (native and denatured) from Machaerocereus gummosus (Pitahaya agria), Lophocereu schottii (Garambullo), and Cholla opuntia (Cholla), was based on electrophoretic, fluorescence, CD (circular dichroism), DSC (differential scanning calorimetry), and FT-IR (Fourier transform infrared) measurements. The obtained results of intrinsic fluorescence, DSC, and CD were dissimilar for the three species of cactus, providing evidence of differences in secondary and tertiary structures. Cactus proteins may be situated in the following order corresponding to their relative stability: Machaerocereus gummosus (Pitahaya agria) > Cholla opuntia (Cholla) > Lophocereu schottii (Garambullo). Thermodynamic properties of proteins and their changes upon denaturation (temperature of denaturation, enthalphy, and the number of ruptured hydrogen bonds) were correlated with the secondary structure of proteins and disappearance of alpha-helix.

  14. Influence of gamma radiation on potato starch gelatinization studied by differential scanning calorimetry

    Science.gov (United States)

    Cieśla, Krystyna; Eliasson, Ann-Charlotte

    2002-05-01

    The paper presents a study of the influence of the conditions applied during differential scanning calorimetry (DSC) measurements (concentration and heating rate) on the possible detection of the differences between gelatinization occurring in both non-irradiated and irradiated potato starch with a dose of 20 kGy. Differences in gelatinization of irradiated and non-irradiated potato starch during DSC analysis was attributed to the radiation induced destruction of crystalline ordering. This was confirmed by studies of the samples irradiated to very high doses (446 and 600 kGy), and by comparing with the effect of grinding. Changes of starch properties caused by radiodepolymerization—contrary to those caused by grinding—influences gelatinization behaviour much more than the WAXS crystallinity in solid state.

  15. Application of differential scanning calorimetry to estimate quality and nutritional properties of food products.

    Science.gov (United States)

    Parniakov, Oleksii; Bals, Olivier; Barba, Francisco J; Mykhailyk, Viacheslav; Lebovka, Nikolai; Vorobiev, Eugene

    2016-05-31

    Over the last years, both food researchers and food industry have shown an increased interest in finding techniques that can estimate the modifications in quality, nutritional and thermophysical properties of food products during processing and/or storage. For instance, differential scanning calorimetry (DSC) has attracted the interest of the scientific community because only a small amount of sample is needed for the analysis. Moreover, it does not require any specific sample preparation and it is a repeatable and reliable method. In addition, DSC methodology needs a short time of experiments compared to other techniques used for the same purpose. At this stage of investigation, there is a need to evaluate the commonly accepted and new emerging DSC applications in order to establish the optimum conditions of emerging processing. This paper reviews the current and new insights of DSC technique for the estimation of quality, nutritional and thermophysical properties of food products during conventional and emerging processing and/or subsequent storage. The estimation of the different properties in several food matrices after processing and/or storage is also discussed.

  16. Multispectral image compression based on DSC combined with CCSDS-IDC.

    Science.gov (United States)

    Li, Jin; Xing, Fei; Sun, Ting; You, Zheng

    2014-01-01

    Remote sensing multispectral image compression encoder requires low complexity, high robust, and high performance because it usually works on the satellite where the resources, such as power, memory, and processing capacity, are limited. For multispectral images, the compression algorithms based on 3D transform (like 3D DWT, 3D DCT) are too complex to be implemented in space mission. In this paper, we proposed a compression algorithm based on distributed source coding (DSC) combined with image data compression (IDC) approach recommended by CCSDS for multispectral images, which has low complexity, high robust, and high performance. First, each band is sparsely represented by DWT to obtain wavelet coefficients. Then, the wavelet coefficients are encoded by bit plane encoder (BPE). Finally, the BPE is merged to the DSC strategy of Slepian-Wolf (SW) based on QC-LDPC by deep coupling way to remove the residual redundancy between the adjacent bands. A series of multispectral images is used to test our algorithm. Experimental results show that the proposed DSC combined with the CCSDS-IDC (DSC-CCSDS)-based algorithm has better compression performance than the traditional compression approaches.

  17. Differential Scanning Calorimetry and Evolved Gas Analysis at Mars Ambient Conditions Using the Thermal Evolved Gas Analyzer (TEGA)

    Science.gov (United States)

    Musselwhite, D. S.; Boynton, W. V.; Ming, Douglas W.; Quadlander, G.; Kerry, K. E.; Bode, R. C.; Bailey, S. H.; Ward, M. G.; Pathare, A. V.; Lorenz, R. D.

    2000-01-01

    Differential Scanning Calorimetry (DSC) combined with evolved gas analysis (EGA) is a well developed technique for the analysis of a wide variety of sample types with broad application in material and soil sciences. However, the use of the technique for samples under conditions of pressure and temperature as found on other planets is one of current C development and cutting edge research. The Thermal Evolved Gas Analyzer (MGA), which was designed, built and tested at the University of Arizona's Lunar and Planetary Lab (LPL), utilizes DSC/EGA. TEGA, which was sent to Mars on the ill-fated Mars Polar Lander, was to be the first application of DSC/EGA on the surface of Mars as well as the first direct measurement of the volatile-bearing mineralogy in martian soil.

  18. Differential Scanning Calorimetry and Evolved Gas Analysis at Mars Ambient Conditions Using the Thermal Evolved Gas Analyser (TEGA)

    Science.gov (United States)

    Musselwhite, D. S.; Boynton, W. V.; Ming, D. W.; Quadlander, G.; Kerry, K. E.; Bode, R. C.; Bailey, S. H.; Ward, M. G.; Pathare, A. V.; Lorenz, R. D.

    2000-01-01

    Differential Scanning Calorimetry (DSC) combined with evolved gas analysis (EGA) is a well developed technique for the analysis of a wide variety of sample types with broad application in material and soil sciences. However, the use of the technique for samples under conditions of pressure and temperature as found on other planets is one of current development and cutting edge research. The Thermal Evolved Gas Analyzer (TEGA), which was designed, built and tested at the University of Arizona's Lunar and Planetary Lab (LPL), utilizes DSC/EGA. TEGA, which was sent to Mars on the ill-fated Mars Polar Lander, was to be the first application of DSC/EGA on the surface of Mars as well as the first direct measurement of the volatile-bearing mineralogy in martian soil. Additional information is available in the original extended abstract.

  19. Simultaneous Synchrotron WAXD and Fast Scanning (Chip) Calorimetry: On the (Isothermal) Crystallization of HDPE and PA11 at High Supercoolings and Cooling Rates up to 200 °C s(-1).

    Science.gov (United States)

    Baeten, Dorien; Mathot, Vincent B F; Pijpers, Thijs F J; Verkinderen, Olivier; Portale, Giuseppe; Van Puyvelde, Peter; Goderis, Bart

    2015-06-01

    An experimental setup, making use of a Flash DSC 1 prototype, is presented in which materials can be studied simultaneously by fast scanning calorimetry (FSC) and synchrotron wide angle X-ray diffraction (WAXD). Accumulation of multiple, identical measurements results in high quality, millisecond WAXD patterns. Patterns at every degree during the crystallization and melting of high density polyethylene at FSC typical scanning rates from 20 up to 200 °C s(-1) are discussed in terms of the temperature and scanning rate dependent material crystallinities and crystal densities. Interestingly, the combined approach reveals FSC thermal lag issues, for which can be corrected. For polyamide 11, isothermal solidification at high supercooling yields a mesomorphic phase in less than a second, whereas at very low supercooling crystals are obtained. At intermediate supercooling, mixtures of mesomorphic and crystalline material are generated at a ratio proportional to the supercooling. This ratio is constant over the isothermal solidification time.

  20. 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.

  1. Advances in simultaneous DSC-FTIR microspectroscopy for rapid solid-state chemical stability studies: some dipeptide drugs as examples.

    Science.gov (United States)

    Lin, Shan-Yang; Wang, Shun-Li

    2012-04-01

    The solid-state chemistry of drugs has seen growing importance in the pharmaceutical industry for the development of useful API (active pharmaceutical ingredients) of drugs and stable dosage forms. The stability of drugs in various solid dosage forms is an important issue because solid dosage forms are the most common pharmaceutical formulation in clinical use. In solid-state stability studies of drugs, an ideal accelerated method must not only be selected by different complicated methods, but must also detect the formation of degraded product. In this review article, an analytical technique combining differential scanning calorimetry and Fourier-transform infrared (DSC-FTIR) microspectroscopy simulates the accelerated stability test, and simultaneously detects the decomposed products in real time. The pharmaceutical dipeptides aspartame hemihydrate, lisinopril dihydrate, and enalapril maleate either with or without Eudragit E were used as testing examples. This one-step simultaneous DSC-FTIR technique for real-time detection of diketopiperazine (DKP) directly evidenced the dehydration process and DKP formation as an impurity common in pharmaceutical dipeptides. DKP formation in various dipeptides determined by different analytical methods had been collected and compiled. Although many analytical methods have been applied, the combined DSC-FTIR technique is an easy and fast analytical method which not only can simulate the accelerated drug stability testing but also at the same time enable to explore phase transformation as well as degradation due to thermal-related reactions. This technique offers quick and proper interpretations.

  2. Process induced transformations during tablet manufacturing: phase transition analysis of caffeine using DSC and low frequency micro-Raman spectroscopy.

    Science.gov (United States)

    Hubert, Sébastien; Briancon, Stéphanie; Hedoux, Alain; Guinet, Yannick; Paccou, Laurent; Fessi, Hatem; Puel, François

    2011-11-25

    The phase transition of a model API, caffeine Form I, was studied during tableting process monitored with an instrumented press. The formulation used had a plastic flow behavior according to the Heckel model in the compression pressure range of 70-170 MPa. The quantitative methods of analysis used were Differential Scanning Calorimetry (DSC) and low frequency Micro Raman Spectroscopy (MRS) which was used for the first time for the mapping of polymorphs in tablets. They brought complementary contributions since MRS is a microscopic spectral analysis with a spatial resolution of 5 μm(3) and DSC takes into account a macroscopic fraction (10mg) of the tablet. Phase transitions were present at the surfaces, borders and center of the tablets. Whatever the pressure applied during the compression process, the transition degree of caffeine Form I toward Form II was almost constant. MRS provided higher transition degrees (50-60%) than DSC (20-35%). MRS revealed that caffeine Form I particles were partially transformed in all parts of the tablets at a microscopic scale. Moreover, tablet surfaces showed local higher transition degree compared to the other parts.

  3. The application of differential scanning calorimetry as a mean to determine the oxidative stability of vegetable oils and its comparison with Rancimat

    Directory of Open Access Journals (Sweden)

    Yousef Ramezan

    2015-09-01

    Full Text Available Differential scanning calorimetry (DSC and Rancimat apparatus have been used to evaluate the oxidative stability of eight different edible vegetable oils. Rancimat apparatus was operated at 110 ⁰C with an air flow of 18-20 L/hand measures the induction period (IP of the selected samples. The DSC technique involved the oxidation of the samples in an oxygen flow DSC cell when the cell temperature was set at isothermal temperatures of 100, 110, 120 and 130 ⁰C. Oxidative induction time (T0 determined by the time, where a rapid exothermic reaction were occurred between oil and oxygen. The results showed that unsaturated edible oils are more susceptible to oxidation in short time, than saturated one. Furthermore, the results indicated that there is a good correlation (p<0.0001 between DSC T0 and the Rancimat values.

  4. 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.

  5. 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].

  6. Isothermal Titration Calorimetry: Assisted Crystallization of RNA-Ligand Complexes.

    Science.gov (United States)

    Da Veiga, Cyrielle; Mezher, Joelle; Dumas, Philippe; Ennifar, Eric

    2016-01-01

    The success rate of nucleic acids/ligands co-crystallization can be significantly improved by performing preliminary biophysical analyses. Among suitable biophysical approaches, isothermal titration calorimetry (ITC) is certainly a method of choice. ITC can be used in a wide range of experimental conditions to monitor in real time the formation of the RNA- or DNA-ligand complex, with the advantage of providing in addition the complete binding profile of the interaction. Following the ITC experiment, the complex is ready to be concentrated for crystallization trials. This chapter describes a detailed experimental protocol for using ITC as a tool for monitoring RNA/small molecule binding, followed by co-crystallization.

  7. 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.

  8. Applications of differential scanning calorimetry to the study of thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Cantor, S.

    1977-01-01

    Differential scanning calorimetry (DSC) is a versatile tool for investigating the behavior of materials that store energy by melting or by undergoing solid-state transitions. Heating scans measure the enthalpy that can be stored and cooling scans yield the enthalpy that may be recovered from the material. Exotherms also provide information about supercooling. The automatic and rapid thermal cycling features of the instrument system can be used to greatly accelerate thermal decomposition that may arise from the daily duty cycle of the storage medium. These chemical reactions as well as those with containment or with substances added to improve performance can be detected from changes in the thermal spectra. In this study, DSC methods were applied to sodium sulfate decahydrate, paraffin wax, urea, and phthalimide. For Na/sub 2/SO/sub 4/.10H/sub 2/O, DSC measurements showed a decrease in heat of fusion with thermal cycling and, also, considerable supercooling; with added Na/sub 2/B/sub 4/O/sub 7/.10H/sub 2/O (borax), supercooling was greatly lessened but not entirely eliminated. Paraffin wax did not supercool nor were there any indications that thermal cycling or contact with aluminum degraded its thermal performance. Urea, when thermally cycled, decreased in melting point and in heat of fusion; this compound also supercooled about 50/sup 0/ in DSC experiments. Phthalimide, C/sub 6/H/sub 4/(CO)/sub 2/NH, did not decompose when thermally cycled through its melting point, but it did exhibit marked supercooling. However, lesser supercooling of urea and phthalimide in test-tube scale experiments suggests that supercooling derived from DSC should be applied with caution. For phthalimide, the enthalpy of fusion, determined in this study, equalled 48.1 cal/g.

  9. 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 ...

  10. 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.

  11. Low Complexity DCT-based DSC approach forHyperspectral Image Compression with Arithmetic Code

    Directory of Open Access Journals (Sweden)

    Meena Babu Vallakati

    2012-09-01

    Full Text Available This paper proposes low complexity codec for lossy compression on a sample hyperspectral image. These images have two kinds of redundancies: 1 spatial; and 2 spectral. A discrete cosine transform (DCT- based Distributed Source Coding(DSC paradigm with Arithmetic code for low complexity is introduced. Here, Set-partitioning based approach is applied to reorganize DCT coefficients into wavelet like tree structure as Setpartitioning works on wavelet transform, and extract the sign, refinement, and significance bitplanes. The extracted refinement bits are Arithmetic encoded, then by applying low density parity check based (LDPC-based Slepian-Wolf coder is implement to our DSC strategy. Experimental results for SAMSON (Spectroscopic Aerial Mapping System with Onboard Navigation data show that proposed scheme achieve peak signal to noise ratio and compression to a very good extent for water cube compared to building, land or forest cube.

  12. Combination of TREF, high-temperature HPLC, FTIR and HPer DSC for the comprehensive analysis of complex polypropylene copolymers.

    Science.gov (United States)

    Cheruthazhekatt, Sadiqali; Pijpers, Thijs F J; Mathot, Vincent B F; Pasch, Harald

    2013-11-01

    A novel, powerful analytical technique, preparative temperature rising elution fractionation (prep TREF)/high-temperature (HT)-HPLC/Fourier transform infrared spectroscopy (FTIR)/high-performance differential scanning calorimetry (HPer DSC)), has been introduced to study the correlation between the polymer chain microstructure and the thermal behaviour of various components in a complex impact polypropylene copolymer (IPC). For the comprehensive analysis of this complex material, in a first step, prep TREF is used to produce less complex but still heterogeneous fractions. These chemically heterogeneous fractions are completely separated by using a highly selective chromatographic separation method--high-temperature solvent gradient HPLC. The detailed structural and thermal analysis of the HPLC fractions was conducted by offline coupling of HT-HPLC with FTIR spectroscopy and a novel DSC method--HPer DSC. Three chemically different components were identified in the mid-elution temperature TREF fractions. For the first component, identified as isotactic polypropylene homopolymer by FTIR, the macromolecular chain length is found to be an important factor affecting the melting and crystallisation behaviour. The second component relates to ethylene-propylene copolymer molecules with varying ethylene monomer distributions and propylene tacticity distributions. For the polyethylene component (last eluting component in all semi-crystalline TREF fractions), it was found that branching produced defects in the long crystallisable ethylene sequences that affected the thermal properties. The different species exhibit distinctively different melting and crystallisation behaviour, as documented by HPer DSC. Using this novel approach of hyphenated techniques, the chain structure and melting and crystallisation behaviour of different components in a complex copolymer were investigated systematically.

  13. Application of differential scanning calorimetry in evaluation of solid state interactions in tablets containing acetaminophen.

    Science.gov (United States)

    Mazurek-Wadołkowska, Edyta; Winnicka, Katarzyna; Czajkowska-Kośnik, Anna; Czyzewska, Urszula; Miltyk, Wojciech

    2013-01-01

    Differential scanning calorimetry (DSC) is an analytical procedure used to determine the differences in the heat flow generated or absorbed by the sample. This method allows to assess purity and polymorphic form of drug compounds, to detect interactions between ingredients of solid dosage forms and to analyze stability of solid formulations. The aim of this study was the assessment of compatibility between acetaminophen (API) and different types of excipients often used in tablets compression: polyvinylpyrrolidone, crospovidone, pregelatinized starch, microcrystalline cellulose and magnesium stearate by differential scanning calorimetry. The study contains results of thermal analysis of excipients and individually performed mixtures of these substances with acetaminophen before and after compression and after 6 months storage of tablets at different temperature and relative humidity conditions (25 +/- 2 degrees C /40 +/- 5% RH, 25 +/- 2 degrees C /60 +/- 5% RH, 40 +/- 2 degrees C /75 +/- 5% RH) for a period of 6 months. To detect possible changes of API chemical structure, gas chromatography-mass spectrometry (GC-MS) was also applied. GC-MS with electron impact ionization (EI) was employed to determine the fragmentation pattern of API. It was shown that the developed formulations showed excellent compatibility among all excipients used except Kollidon CL. The interaction with Kollidon CL is probably a result of a physical reaction as confirmed by GC-MS analyses. Obtained results revealed that DSC can be successfully applied to evaluate possible incompatibilities between acetaminophen and Kollidon.

  14. In situ stability of substrate-associated cellulases studied by DSC.

    Science.gov (United States)

    Alasepp, Kadri; Borch, Kim; Cruys-Bagger, Nicolaj; Badino, Silke; Jensen, Kenneth; Sørensen, Trine H; Windahl, Michael S; Westh, Peter

    2014-06-24

    This work shows that differential scanning calorimetry (DSC) can be used to monitor the stability of substrate-adsorbed cellulases during long-term hydrolysis of insoluble cellulose. Thermal transitions of adsorbed enzyme were measured regularly in subsets of a progressing hydrolysis, and the size of the transition peak was used as a gauge of the population of native enzyme. Analogous measurements were made for enzymes in pure buffer. Investigations of two cellobiohydrolases, Cel6A and Cel7A, from Trichoderma reesei, which is an anamorph of the fungus Hypocrea jerorina, showed that these enzymes were essentially stable at 25 °C. Thus, over a 53 h experiment, Cel6A lost less than 15% of the native population and Cel7A showed no detectable loss for either the free or substrate-adsorbed state. At higher temperatures we found significant losses in the native populations, and at the highest tested temperature (49 °C) about 80% Cel6A and 35% of Cel7A was lost after 53 h of hydrolysis. The data consistently showed that Cel7A was more long-term stable than Cel6A and that substrate-associated enzyme was less long-term stable than enzyme in pure buffer stored under otherwise equal conditions. There was no correlation between the intrinsic stability, specified by the transition temperature in the DSC, and the long-term stability derived from the peak area. The results are discussed with respect to the role of enzyme denaturation for the ubiquitous slowdown observed in the enzymatic hydrolysis of cellulose.

  15. 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.

  16. 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.

  17. Evaluation of the modified nanoclay effect on the vulcanization of SBR through rheometric curve and DSC;Avaliacao do efeito de nanoargila modificada na vulcanizacao de SBR atraves da curva reometrica e DSC

    Energy Technology Data Exchange (ETDEWEB)

    Forte, Maria Madalena C.; Brito, Karin J.S., E-mail: mmcforte@ufrgs.b [Universidade Federal do Rio Grande do Sul (PPGEM/UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia Mecanica; Gheller Junior, Jordao [SENAI, Sao Leopoldo, RS (Brazil). Centro Tecnologico de Polimeros

    2009-07-01

    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 Cloisite{sup R} 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 (DELTAH{sub v}) 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)

  18. Thermodynamic Property Study of Nanostructured Mg-H, Mg-Ni-H, and Mg-Cu-H Systems by High Pressure DSC Method

    Directory of Open Access Journals (Sweden)

    Huaiyu Shao

    2013-01-01

    Full Text Available 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 nanostructured 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.

  19. DSC Study on the Thermal Hysteresis Activity of Plant Antifreeze Proteins%沙冬青抗冻蛋白热滞活性的DSC研究

    Institute of Scientific and Technical Information of China (English)

    周晓蕾; 陈滔滔; 王保怀; 李芝芬; 费云标; 魏令波; 高素琴

    2001-01-01

    Differential scanning calorimetry (DSC) was used to measure thethermal hysteresis activity(THA) of plant antifreeze proteins(AFPs). The results reveal that DSC is a good method to screen and study AFPs. In the sixteen components extracted from Ammopipanthus mongolicus leaves, one(P3S1) was found to have apparent thermal hysteresis activity by DSC. As the amount of ice nuclei in the sample decreased, the THA of P3S1 increased from 0.01 ℃ to 0.65 ℃ . It is notable that the two-peak thermal hysteresis effect was observed. Two endothermic peaks appeared in the melting process of P3S1, while the freezing peak also consisted of two peaks. The peaks appeared antecedently showed larger thermal effect. This phenomenon shows P3S1 has two different kinds of interaction with water and ice crystal. It is probably an important property of a class of AFPs.

  20. Qualitative and kinetic analysis of torrefaction of lignocellulosic biomass using DSC-TGA-FTIR

    Directory of Open Access Journals (Sweden)

    Bimal Acharya

    2015-11-01

    Full Text Available Torrefaction is a thermochemical conversion technique to improve the fuel properties of lignocellulosic biomass by treating at temperature 200 ℃-300 ℃ in the minimum oxygen environment for a reasonable residence time. In this study, thermal decomposition and thermal activities of miscanthus and wheat straw during the torrefaction at 200 ℃, 275 ℃, and 300 ℃ in a nitrogen environment for 45 minutes of residence time are analyzed in a simultaneous thermogravimetric analyzer (micro TGA with a differential scanning calorimetry (DSC, and a macro-TGA. The output of the micro TGA is fed into the Fourier transform infrared spectrometry (FTIR and qualitative analysis of the gaseous product is carried out. The composition of different gas products during the torrefaction of biomass are compared critically and kinetics were analyzed. It is found that the weight loss due to degradation of initial biomass in second stage (torrefaction process is a much faster conversion process than the weight loss process in the first stage (drying process. The weight loss of biomass increases with increase in the residence time and torrefaction treatment temperatures. The yield after torrefaction is a solid bio-coal product. The torrefied product were less reactive and has nearly 25% better heating value than the raw biomass. Between the two feedstocks studied, torrefied miscanthus proved to be a more stable fuel than the torrefied wheat straw. The major gaseous components observed during torrefaction are water, carbon dioxide, carbon monoxide, 1,2-Dibromethylene.

  1. DSC studies of retrogradation and amylose lipid complex transition taking place in gamma irradiated wheat starch

    Science.gov (United States)

    Cieśla, K.; Eliasson, A. C.

    2007-12-01

    The effect of gamma irradiation ( 60Co) with doses of 5-30 kGy on the amylose-lipid complex transition and retrogradation occurring in gels containing ca. 50% and ca. 20% wheat starch was studied by differential scanning calorimetry (DSC) during heating-cooling-heating cycles (up to three cycles). Transition of the amylose-lipid complex occurs in all the irradiated samples at a lower temperature as compared to the non-irradiated starch. That effect was larger when the radiation dose was higher. A further thermal treatment causes a decrease of the transition temperature in the irradiated samples, with no effect or increase of that temperature observed for the non-irradiated ones. Irradiation hinders retrogradation taking place in 50% gels but facilitates the process occurring in 20% gels. The differences between the irradiated and the non-irradiated samples are more evident in the every next heating or cooling cycle as well as after storage and in the case of ca. 50% suspensions as compared to ca. 20% suspensions. The results point out to the deterioration of the structure of the complexes formed in the irradiated starch as compared to the non-irradiated one.

  2. Thermal characterization and model free kinetics of aged epoxies and foams using TGA and DSC methods.

    Energy Technology Data Exchange (ETDEWEB)

    Cordaro, Joseph Gabriel; Kruizenga, Alan Michael; Nissen, April

    2013-10-01

    Two classes of materials, poly(methylene diphenyl diisocyanate) or PMDI foam, and cross-linked epoxy resins, were characterized using thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC), to help understand the effects of aging and %E2%80%9Cbake-out%E2%80%9D. The materials were evaluated for mass loss and the onset of decomposition. In some experiments, volatile materials released during heating were analyzed via mass spectroscopy. In all, over twenty materials were evaluated to compare the mass loss and onset temperature for decomposition. Model free kinetic (MFK) measurements, acquired using variable heating rate TGA experiments, were used to calculate the apparent activation energy of thermal decomposition. From these compiled data the effects of aging, bake-out, and sample history on the thermal stability of materials were compared. No significant differences between aged and unaged materials were detected. Bake-out did slightly affect the onset temperature of decomposition but only at the highest bake-out temperatures. Finally, some recommendations for future handling are made.

  3. Isothermal titration calorimetry: general formalism using binding polynomials.

    Science.gov (United States)

    Freire, Ernesto; Schön, Arne; Velazquez-Campoy, Adrian

    2009-01-01

    The theory of the binding polynomial constitutes a very powerful formalism by which many experimental biological systems involving ligand binding can be analyzed under a unified framework. The analysis of isothermal titration calorimetry (ITC) data for systems possessing more than one binding site has been cumbersome because it required the user to develop a binding model to fit the data. Furthermore, in many instances, different binding models give rise to identical binding isotherms, making it impossible to discriminate binding mechanisms using binding data alone. One of the main advantages of the binding polynomials is that experimental data can be analyzed by employing a general model-free methodology that provides essential information about the system behavior (e.g., whether there exists binding cooperativity, whether the cooperativity is positive or negative, and the magnitude of the cooperative energy). Data analysis utilizing binding polynomials yields a set of binding association constants and enthalpy values that conserve their validity after the correct model has been determined. In fact, once the correct model is validated, the binding polynomial parameters can be immediately translated into the model specific constants. In this chapter, we describe the general binding polynomial formalism and provide specific theoretical and experimental examples of its application to isothermal titration calorimetry.

  4. Vapour liquid equilibria of monocaprylin plus palmitic acid or methyl stearate at P=(1.20 and 2.50) kPa by using DSC technique

    DEFF Research Database (Denmark)

    Cunico, Larissa P.; Damaceno, Daniela S.; Matricarde Falleiro, Rafael M.;

    2015-01-01

    The Differential Scanning Calorimetry (DSC) technique is used for measuring isobaric (vapour+liquid) equilibria for two binary mixtures: {monocaprylin+palmitic acid (system 1) or methyl stearate (system 2)} at two different pressures P=(1.20 and 2.50) kPa. The obtained PTx data are correlated...... that no such data could be found in the open literature, not only for the specific components selected but also for the combination of the classes of components considered; that is, acylglycerol plus fatty acid or fatty ester....

  5. 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

  6. 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.

  7. 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)

  8. 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.

  9. Study of asphaltene precipitation by Calorimetry

    DEFF Research Database (Denmark)

    Verdier, Sylvain Charles Roland; Plantier, Frédéric; Bessières, David;

    2007-01-01

    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...

  10. Use of the DSC technique to characterize water-in-crude oil emulsions stability; Utilisation de la DSC pour la caracterisation de la stabilite des emulsions eau dans petrole

    Energy Technology Data Exchange (ETDEWEB)

    Dalmazzone, C.; Seris, H. [Institut Francais du Petrole (IFP), 92 - Rueil-Malmaison (France)

    1998-07-01

    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 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 the assessment of emulsions stability. They are generally based on the analysis of the droplets size distribution. Unfortunately, most of the usual techniques can not be applied to opaque water-in-oil emulsions. The most useful method to characterize the stability of emulsions is of course the `bottle test`. It consists in monitoring the extent of phase separation with time. This type of test provides a significant amount of information relating to both the stability of the emulsion phase and the clarity of he separated water, but it is very empirical. The DSC technique is generally used to determine the composition of water-in-oil emulsions. It is the only technique capable of distinguishing free water from emulsified water. It was shown in this study that it is a very useful technique, which allows the study of the evolution of the droplet size distribution as well as a precise determination of the water content. (authors) 15 refs.

  11. 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

  12. 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.

  13. Evaluation of the Ignition Temperature in Thermal Explosion Synthesis of TiAl3 by Differential Scanning Calorimetry

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Application of the Semenov theory of spontaneous ignition to evaluation of the critical temperature (Tc′) in thermal explosion (TE) synthesis was conducted with the Ti-75at pct Al binary system using nonisothermal differential scanning calorimetry (DSC) at different heating rates. And the critical temperature for isothermal TE is predicted to be 728.9°C by the multiple linear regression of Tc′s evaluated according to Semenov theory, which is close to the range of 740~745°C obtained from the isothermal DSC observation. This result proves that Semenov theory of spontaneous ignition is also feasible for TE synthesis in binary metallic systems like Ti-75 at. pct Al system.

  14. 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.

  15. Calibration and monitoring for crystal calorimetry

    CERN Document Server

    Zhu, Ren Yuan

    2005-01-01

    Crystal calorimetry provides excellent energy resolution in high energy and nuclear physics. The light output of heavy crystal scintillators, however, suffers from not negligible damage in radiation environment. A precision calibration and monitoring thus is crucial for maintaining crystal precision in situ. The performance of calibration and monitoring approaches used by BaBar, CLEO and L3 experiments are presented. The design and construction of a laser- based light monitoring system for CMS PWO calorimeter is also discussed.

  16. Foward Calorimetry in ALICE at LHC

    Science.gov (United States)

    Chujo, Tatsuya; Alice Focal Collaboration

    2014-09-01

    We present an upgrade proposal for calorimetry in the forward direction, FOCAL, to measure direct photons in η = 3 . 3 - 5 . 3 in ALICE at the Large Hadron Collider (LHC). We suggest to use an electromagnetic calorimeter based on the novel technology of silicon sensors with W absorbers for photons, together with a conventional hadron calorimeter for jet measurements and photon isolation. The current status of the FOCAL R&D project will be presented.

  17. 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.

  18. 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.

  19. The oxidation of aluminum at high temperature studied by Thermogravimetric Analysis and Differential Scanning Calorimetry.

    Energy Technology Data Exchange (ETDEWEB)

    Coker, Eric Nicholas

    2013-10-01

    The oxidation in air of high-purity Al foil was studied as a function of temperature using Thermogravimetric Analysis with Differential Scanning Calorimetry (TGA/DSC). The rate and/or extent of oxidation was found to be a non-linear function of the temperature. Between 650 and 750 ÀC very little oxidation took place; at 850 ÀC oxidation occurred after an induction period, while at 950 ÀC oxidation occurred without an induction period. At oxidation temperatures between 1050 and 1150 ÀC rapid passivation of the surface of the aluminum foil occurred, while at 1250 ÀC and above, an initial rapid mass increase was observed, followed by a more gradual increase in mass. The initial rapid increase was accompanied by a significant exotherm. Cross-sections of oxidized specimens were characterized by scanning electron microscopy (SEM); the observed alumina skin thicknesses correlated qualitatively with the observed mass increases.

  20. 索尼DSC-P200数码相机

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    作为面向普通家用的时尚主打机型,索尼DSC-P系列一直保持着相当高的市场份额,在DSC-P150把家用数码相机带到700万像素级后,索尼继续推出了DSC-P150的升级机型DSC-P200。

  1. 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.

  2. Differential scanning calorimetry and reaction kinetics studies of {gamma} + {alpha}{sub 2} Ti aluminide

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, R.K., E-mail: rohitkumar_gupta@vssc.gov.in [Vikram Sarabhai Space Centre, ISRO, Trivandrum 695 022 (India); Pant, Bhanu [Vikram Sarabhai Space Centre, ISRO, Trivandrum 695 022 (India); Agarwala, Vijaya [Indian Institute of Technology Roorkee, Roorkee 247 667 (India); Sinha, P.P. [Vikram Sarabhai Space Centre, ISRO, Trivandrum 695 022 (India)

    2012-12-14

    Reaction synthesis method for titanium aluminide processing consists of an exothermic reaction among alloying elements present and primarily between titanium and aluminium particles at specific temperature range. Study of this reaction helps in understanding the process of aluminide formation. Differential scanning calorimetry (DSC) study is the suitable method to study such reactions. In the present work, five different alloy mixtures based on Ti48Al2Cr2Nb0.1B are prepared and DSC study is carried out. Onset temperature, peak temperature and completion temperature of the major exothermic reaction is analyzed at different heating rates. Further, kinetics of the reaction is studied using Johnson-Mehl-Avrami equation. Activation energy and Avrami parameter are calculated and compared with the reported works on binary alloy. It has been observed that exothermic reaction is triggered by melting of aluminium. Boron assists in increasing the enthalpy of reaction by boride formation. Primary reaction product is found to be TiAl{sub 3}. Activation energy as well as Avrami parameter is found to have marginal variation due to small change in alloying elements in different alloys and due to heating rates in the same alloy. -- Highlights: Black-Right-Pointing-Pointer Reaction kinetics studies of Ti-aluminide alloy powder mixtures carried out. Black-Right-Pointing-Pointer Five compositions studied through non-isothermal differential scanning calorimetry. Black-Right-Pointing-Pointer Effect of minor boron addition and role of Ti particle size is noted. Black-Right-Pointing-Pointer Activation energies using JMA equations are between 169.5 and 192.49 kJ mol{sup -1}.

  3. Reliability prediction of I&C cable insulation materials by DSC and Weibull theory for probabilistic safety assessment of NPPs

    Energy Technology Data Exchange (ETDEWEB)

    Santhosh, T.V., E-mail: santutv@barc.gov.in [Reactor Safety Division, Bhabha Atomic Research Centre (India); Gopika, V. [Reactor Safety Division, Bhabha Atomic Research Centre (India); Ghosh, A.K. [Raja Ramanna Fellow, Department of Atomic Energy (India); Fernandes, B.G. [Department of Electrical Engineering, Indian Institute of Technology Bombay (India); Dubey, K.A. [Radiation Technology Development Division, Bhabha Atomic Research Centre (India)

    2016-01-15

    calorimetry (DSC). As elongation at break (EAB) is considered to be a benchmark characterization technique for polymeric materials, tensile tests have also been carried out on these cable materials for correlating with DSC findings. The Fourier transform infrared (FTIR) spectroscopy has also been carried out on fresh and irradiated samples to monitor the structural changes in the insulation materials. The correlations obtained from DSC and FTIR studies are relatively in good agreement with the tensile testing results. The images of scanning electron microscopy (SEM) on fresh and aged samples support the degradation predicted from infrared spectroscopy, thermal and mechanical measurements. The time dependent reliability predicted from the OIT based on Weibull theory will be useful in incorporating the cable ageing into PSA of NPPs.

  4. Unspecific membrane protein-lipid recognition: combination of AFM imaging, force spectroscopy, DSC and FRET measurements.

    Science.gov (United States)

    Borrell, Jordi H; Montero, M Teresa; Morros, Antoni; Domènech, Òscar

    2015-11-01

    In this work, we will describe in quantitative terms the unspecific recognition between lactose permease (LacY) of Escherichia coli, a polytopic model membrane protein, and one of the main components of the inner membrane of this bacterium. Supported lipid bilayers of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG) (3:1, mol/mol) in the presence of Ca(2+) display lateral phase segregation that can be distinguished by atomic force microscopy (AFM) as well as force spectroscopy. LacY shows preference for fluid (Lα) phases when it is reconstituted in POPE : POPG (3:1, mol/mol) proteoliposomes at a lipid-to-protein ratio of 40. When the lipid-to-protein ratio is decreased down to 0.5, two domains can be distinguished by AFM. While the upper domain is formed by self-segregated units of LacY, the lower domain is constituted only by phospholipids in gel (Lβ) phase. On the one hand, classical differential scanning calorimetry (DSC) measurements evidenced the segregation of a population of phospholipids and point to the existence of a boundary region at the lipid-protein interface. On the other hand, Förster Resonance Energy Transfer (FRET) measurements in solution evidenced that POPE is selectively recognized by LacY. A binary pseudophase diagram of POPE : POPG built from AFM observations enables to calculate the composition of the fluid phase where LacY is inserted. These results are consistent with a model where POPE constitutes the main component of the lipid-LacY interface segregated from the fluid bulk phase where POPG predominates.

  5. Bicellar mixture phase behavior examined by variable-pressure deuterium NMR and ambient pressure DSC.

    Science.gov (United States)

    Uddin, Md Nasir; Morrow, Michael R

    2010-07-20

    Variable-pressure deuterium nuclear magnetic resonance ((2)H NMR) has been used to study the pressure-temperature phase diagram of bicellar mixtures containing 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC). Spectra were obtained for DMPC-d(54)/DHPC (3:1), DMPC-d(54)/DHPC (4.4:1), DMPC/DHPC-d(22) (3:1), and DMPC/DHPC-d(22) (4.4:1) in the range 10-68 degrees C at ambient pressure, 66 MPa, 102 MPa, and 135 MPa. Isotropic-to-nematic and nematic-to-lamellar transition temperatures were found to rise with pressure at approximately 0.15 and approximately 0.14 degrees C/MPa, respectively, for DMPC-d(54)/DHPC (3:1) and at at approximately 0.19 and approximately 0.18 degrees C/MPa, respectively, for DMPC-d(54)/DHPC (4.4:1). Pressure had little effect on the range of DMPC-d(54) chain orientational order through the nematic phase temperature range, but the behavior of chain orientational order at the nematic-to-lamellar transition was found to vary slightly with pressure. Comparison of differential scanning calorimetry (DSC) observations with ambient-pressure (2)H NMR observations of DMPC-d(54) in the bicellar mixtures suggests that absorption of heat persists for a few degrees above the onset of axially symmetric DMPC-d(54) reorientation.

  6. Profiles in Leadership: Clifton J. Latiolais, MSc, DSc.

    Science.gov (United States)

    White, Sara; Godwin, Harold N; Weber, Robert J

    2013-09-01

    The Director's Forum series is designed to guide pharmacy leaders in establishing patient-centered services in hospitals and health systems. August 2013 marks the 50th anniversary of the publication of the Mirror to Hospital Pharmacy, which was a comprehensive study of pharmacy services in the United States. The late Clifton J. Latiolais, MS, DSc, served as the assistant program director for the study and was a co-author of the Mirror. The late Don E. Francke, MS, DSc, was the lead author of the Mirror and the principal investigator of the federally funded study that reviewed hospital pharmacy services across the United States. The next 2 articles in Director's Forum profile the leadership of Drs. Latiolais and Francke. This article highlights Dr. Latiolais ("Clif") by briefly reviewing his biography and key career accomplishments, describing his leadership philosophy, and translating that philosophy to today's health care challenges. Clif's influence on health system pharmacy serves as an example of effective leadership. This historical perspective on Clif's leadership, as seen through the eyes of those who knew him, provides directors of pharmacy a valuable leadership viewpoint as they develop strategies to enhance patient-centered pharmacy services.

  7. Study on biodegradation process of lignin by FTIR and DSC.

    Science.gov (United States)

    Liu, Yang; Hu, Tianjue; Wu, Zhengping; Zeng, Guangming; Huang, Danlian; Shen, Ying; He, Xiaoxiao; Lai, Mingyong; He, Yibin

    2014-12-01

    The biodegradation process of lignin by Penicillium simplicissimum was studied to reveal the lignin biodegradation mechanisms. The biodegradation products of lignin were detected using Fourier transform infrared spectroscopy (FTIR), UV-Vis spectrophotometer, different scanning calorimeter (DSC), and stereoscopic microscope. The analysis of FTIR spectrum showed the cleavage of various ether linkages (1,365 and 1,110 cm(-1)), oxidation, and demethylation (2,847 cm(-1)) by comparing the different peak values in the corresponding curve of each sample. Moreover, the differences (Tm and ΔHm values) between the DSC curves indirectly verified the FTIR analysis of biodegradation process. In addition, the effects of adding hydrogen peroxide (H2O2) to lignin biodegradation process were analyzed, which indicated that H2O2 could accelerate the secretion of the MnP and LiP and improve the enzymes activity. What is more, lignin peroxidase and manganese peroxidase catalyzed the lignin degradation effectively only when H2O2 was presented.

  8. 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.

  9. Analytic heuristics for a fast DSC-MRI

    Science.gov (United States)

    Virgulin, M.; Castellaro, M.; Marcuzzi, F.; Grisan, E.

    2014-03-01

    Hemodynamics of the human brain may be studied with Dynamic Susceptibility Contrast MRI (DSC-MRI) imaging. The sequence of volumes obtained exhibits a strong spatiotemporal correlation, that can be exploited to predict which measurements will bring mostly the new information contained in the next frames. In general, the sampling speed is an important issue in many applications of the MRI, so that the focus of many current researches is to study methods to reduce the number of measurement samples needed for each frame without degrading the image quality. For the DSC-MRI, the frequency under-sampling of single frame can be exploited to make more frequent space or time acquisitions, thus increasing the time resolution and allowing the analysis of fast dynamics not yet observed. Generally (and also for MRI), the recovery of sparse signals has been achieved by Compressed Sensing (CS) techniques, which are based on statistical properties rather than deterministic ones.. By studying analytically the compound Fourier+Wavelet transform, involved in the processes of reconstruction and sparsification of MR images, we propose a deterministic technique for a rapid-MRI, exploiting the relations between the wavelet sparse representation of the recovered and the frequency samples. We give results on real images and on artificial phantoms with added noise, showing the superiority of the methods both with respect to classical Iterative Hard Thresholding (IHT) and to Location Constraint Approximate Message Passing (LCAMP) reconstruction algorithms.

  10. 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.

  11. Determination of the thermo-mechanical properties in starch and starch/gluten systems at low moisture content - a comparison of DSC and TMA.

    Science.gov (United States)

    Homer, Stephen; Kelly, Michael; Day, Li

    2014-08-08

    The impact of heating rate on the glass transition (Tg) and melting transitions observed by differential scanning calorimetry (DSC) on starch and a starch/gluten blend (80:20 ratio) at low moisture content was examined. The results were compared to those determined by thermo-mechanical analysis (TMA). Comparison with dynamic mechanical thermal analysis (DMTA) and phase transition analysis (PTA) is also discussed. Higher heating rates increased the determined Tg as well as the melting peak temperatures in both starch and the starch/gluten blend. A heating rate of 5°C/min gave the most precise value of Tg while still being clearly observed above the baseline. Tg values determined from the first and second DSC scans were found to differ significantly and retrogradation of starch biopolymers may be responsible. Tg values of starch determined by TMA showed good agreement with DSC results where the Tg was below 80°C. However, moisture loss led to inaccurate Tg determination for TMA analyses at temperatures above 80°C.

  12. An evaluation tool for FKBP12-dependent and -independent mTOR inhibitors using a combination of FKBP-mTOR fusion protein, DSC and NMR.

    Science.gov (United States)

    Sekiguchi, Mitsuhiro; Kobashigawa, Yoshihiro; Kawasaki, Masashi; Yokochi, Masashi; Kiso, Tetsuo; Suzumura, Ken-ichi; Mori, Keitaro; Teramura, Toshio; Inagaki, Fuyuhiko

    2011-11-01

    Mammalian target of rapamycin (mTOR), a large multidomain protein kinase, regulates cell growth and metabolism in response to environmental signals. The FKBP rapamycin-binding (FRB) domain of mTOR is a validated therapeutic target for the development of immunosuppressant and anticancer drugs but is labile and insoluble. Here we designed a fusion protein between FKBP12 and the FRB domain of mTOR. The fusion protein was successfully expressed in Escherichia coli as a soluble form, and was purified by a simple two-step chromatographic procedure. The fusion protein exhibited increased solubility and stability compared with the isolated FRB domain, and facilitated the analysis of rapamycin and FK506 binding using differential scanning calorimetry (DSC) and solution nuclear magnetic resonance (NMR). DSC enabled the rapid observation of protein-drug interactions at the domain level, while NMR gave insights into the protein-drug interactions at the residue level. The use of the FKBP12-FRB fusion protein combined with DSC and NMR provides a useful tool for the efficient screening of FKBP12-dependent as well as -independent inhibitors of the mTOR FRB domain.

  13. Probing lipid-cholesterol interactions in DOPC/eSM/Chol and DOPC/DPPC/Chol model lipid rafts with DSC and (13)C solid-state NMR.

    Science.gov (United States)

    Fritzsching, Keith J; Kim, Jihyun; Holland, Gregory P

    2013-08-01

    The interaction between cholesterol (Chol) and phospholipids in bilayers was investigated for the ternary model lipid rafts, DOPC/eSM/Chol and DOPC/DPPC/Chol, with differential scanning calorimetry (DSC) and (13)C cross polarization magic angle spinning (CP-MAS) solid-state NMR. The enthalpy and transition temperature (Tm) of the Lα liquid crystalline phase transition from DSC was used to probe the thermodynamics of the different lipids in the two systems as a function of Chol content. The main chain (13)C (CH2)n resonance is resolved in the (13)C CP-MAS NMR spectra for the unsaturated (DOPC) and saturated (eSM or DPPC) chain lipid in the ternary lipid raft mixtures. The (13)C chemical shift of this resonance can be used to detect differences in chain ordering and overall interactions with Chol for the different lipid constituents in the ternary systems. The combination of DSC and (13)C CP-MAS NMR results indicate that there is a preferential interaction between SM and Chol below Tm for the DOPC/eSM/Chol system when the Chol content is ≤20mol%. In contrast, no preferential interaction between Chol and DPPC is observed in the DOPC/DPPC/Chol system above or below Tm. Finally, (13)C CP-MAS NMR resolves two Chol environments in the DOPC/eSM/Chol system below Tm at Chol contents >20mol% while, a single Chol environment is observed for DOPC/DPPC/Chol at all compositions.

  14. Multivariate analysis of DSC-XRD simultaneous measurement data: a study of multistage crystalline structure changes in a linear poly(ethylene imine) thin film.

    Science.gov (United States)

    Kakuda, Hiroyuki; Okada, Tetsuo; Otsuka, Makoto; Katsumoto, Yukiteru; Hasegawa, Takeshi

    2009-01-01

    A multivariate analytical technique has been applied to the analysis of simultaneous measurement data from differential scanning calorimetry (DSC) and X-ray diffraction (XRD) in order to study thermal changes in crystalline structure of a linear poly(ethylene imine) (LPEI) film. A large number of XRD patterns generated from the simultaneous measurements were subjected to an augmented alternative least-squares (ALS) regression analysis, and the XRD patterns were readily decomposed into chemically independent XRD patterns and their thermal profiles were also obtained at the same time. The decomposed XRD patterns and the profiles were useful in discussing the minute peaks in the DSC. The analytical results revealed the following changes of polymorphisms in detail: An LPEI film prepared by casting an aqueous solution was composed of sesquihydrate and hemihydrate crystals. The sesquihydrate one was lost at an early stage of heating, and the film changed into an amorphous state. Once the sesquihydrate was lost by heating, it was not recovered even when it was cooled back to room temperature. When the sample was heated again, structural changes were found between the hemihydrate and the amorphous components. In this manner, the simultaneous DSC-XRD measurements combined with ALS analysis proved to be powerful for obtaining a better understanding of the thermally induced changes of the crystalline structure in a polymer film.

  15. 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.

  16. Morphological Investigation into Starch Bio-Nanocomposites via Synchrotron Radiation and Differential Scanning Calorimetry

    Directory of Open Access Journals (Sweden)

    Huihua Liu

    2011-01-01

    Full Text Available We studied a hydrophilic, plasticized bionanocomposite system involving sorbitol plasticizer, amylose biopolymer, and montmorillonite (MMT for the presence of competitive interactions among them at different moisture content. Synchrotron analysis via small angle X-ray scattering (SAXS and thermal analysis using differential scanning calorimetry (DSC were performed to understand crystalline growth and the distribution of crystalline domains within the samples. The SAXS diffraction patterns showed reduced interhelix spacing in the amylose network indicating strong amylose-sorbitol interactions. Depending on the sorbitol and MMT concentration, these interactions also affected the free moisture content and crystalline domains. Domains of around 95 Å and 312 Å were found in the low-moisture-content samples as compared to a single domain of 95 Å in the high-moisture-content samples. DSC measurements confirmed that the MMT increased the onset and the melting temperature of nanocomposites. Moreover, the results showed that the ternary interactions among sorbitol-amylose-MMT supported the crystalline heterogeneity through secondary nucleation.

  17. Assessment of fluidity of different invasomes by electron spin resonance and differential scanning calorimetry.

    Science.gov (United States)

    Dragicevic-Curic, Nina; Friedrich, Manfred; Petersen, Silvia; Scheglmann, Dietrich; Douroumis, Dennis; Plass, Winfried; Fahr, Alfred

    2011-06-30

    The aim of this study was to investigate the influence of membrane-softening components (terpenes/terpene mixtures, ethanol) on fluidity of phospholipid membranes in invasomes, which contain besides phosphatidylcholine and water, also ethanol and terpenes. Also mTHPC was incorporated into invasomes in order to study its molecular interaction with phospholipids in vesicular membranes. Fluidity of bilayers was investigated by electron spin resonance (ESR) using spin labels 5- and 16-doxyl stearic acid and by differential scanning calorimetry (DSC). Addition of 1% of a single terpene/terpene mixture led to significant fluidity increase around the C16 atom of phospholipid acyl chains comprising the vesicles. However, it was not possible to differentiate between the influences of single terpenes or terpene mixtures. Incorporation of mTHPC into the bilayer of vesicles decreased fluidity near the C16 atom of acyl chains, indicating its localization in the inner hydrophobic zone of bilayers. These results are in agreement with DSC measurements, which showed that terpenes increased fluidity of bilayers, while mTHPC decreased fluidity. Thus, invasomes represent vesicles with very high membrane fluidity. However, no direct correlation between fluidity of invasomes and their penetration enhancing ability was found, indicating that besides fluidity also other phenomena might be responsible for improved skin delivery of mTHPC.

  18. 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.....

  19. Technical decision making with higher order structure data: utilization of differential scanning calorimetry to elucidate critical protein structural changes resulting from oxidation.

    Science.gov (United States)

    Arthur, Kelly K; Dinh, Nikita; Gabrielson, John P

    2015-04-01

    Differential scanning calorimetry (DSC) is a useful tool for monitoring thermal stability of the molecular conformation of proteins. Here, we present an example of the sensitivity of DSC to changes in stability arising from a common chemical degradation pathway, oxidation. This Note is part of a series of industry case studies demonstrating the application of higher order structure data for technical decision making. For this study, six protein products from three structural classes were evaluated at multiple levels of oxidation. For each protein, the melting temperature (Tm ) decreased linearly as a function of oxidation; however, differences in the rate of change in Tm , as well as differences in domain Tm stability were observed across and within structural classes. For one protein, analysis of the impact of oxidation on protein function was also performed. For this protein, DSC was shown to be a leading indicator of decreased antigen binding suggesting a subtle conformation change may be underway that can be detected using DSC prior to any observable impact on product potency. Detectable changes in oxidized methionine by mass spectrometry (MS) occurred at oxidation levels below those with a detectable conformational or functional impact. Therefore, by using MS, DSC, and relative potency methods in concert, the intricate relationship between a primary structural modification, changes in conformational stability, and functional impact can be elucidated.

  20. Improving the dispersity of detonation nanodiamond: differential scanning calorimetry as a new method of controlling the aggregation state of nanodiamond powders.

    Science.gov (United States)

    Korobov, Mikhail V; Volkov, Dmitry S; Avramenko, Natalya V; Belyaeva, Lubov' A; Semenyuk, Pavel I; Proskurnin, Mikhail A

    2013-02-21

    Detonation nanodiamond (ND) is a suitable source material to produce unique samples consisting of almost uniform diamond nanocrystals (d = 3-5 nm). Such samples exist in the form of long stable aqueous dispersions with narrow size distribution of diamond particles. The material is finding ever increasing application in biomedicine. The major problem in producing monodispersed diamond colloids lies in the necessity of deagglomeration of detonation soot and/or removing of clusters formed by already isolated core particles in dry powders. To do this one must have an effective method to monitor the aggregation state or dispersity of powders and gels prior to the preparation of aqueous dispersions. In the absence of dispersity control at various stages of preparation the reproducibility of properties of existing ND materials is poor. In this paper we introduce differential scanning calorimetry (DSC) as a new tool capable to distinguish the state of aggregation in dry and wetted ND materials and to follow changes in this state under different types of treatment. Samples with identical X-ray diffraction patterns (XRD) and high resolution transmission electron microscopy (HRTEM) images gave visibly different DSC traces. Strong correlation was found between dynamic light scattering (DLS) data for colloids and DSC parameters for gels and powders of the same material. Based on DSC data we improved dispersity of existing ND materials and isolated samples with the best possible DSC parameters. These were true monodispersed easily dispersible fractions of ND particles with diameters of ca. 3 nm.

  1. Overriding "doing wrong" and "not doing right": validation of the Dispositional Self-Control Scale (DSC).

    Science.gov (United States)

    Ein-Gar, Danit; Sagiv, Lilach

    2014-01-01

    We present the Dispositional Self-Control (DSC) Scale, which reflects individuals' tendency to override 2 types of temptations, termed doing wrong and not doing right. We report a series of 5 studies designed to test the reliability and validity of the scale. As hypothesized, high DSC predicts distant future orientation and low DSC predicts deviant behaviors such as aggression, alcohol misuse, and aberrant driving. DSC also predicts task performance among resource-depleted participants. Taken together, these findings suggest that the DSC Scale could be a useful tool toward further understanding the role of personality in overcoming self-control challenges.

  2. 自我增值这选:Sony DSC-F717

    Institute of Scientific and Technical Information of China (English)

    高飞

    2002-01-01

    近年的10月都是Sony推出旗舰级数码相机的日子,2000年的DSC-505v、2001年的DSC-F707,2002年有这部终极强化版的DSC-F717。改用回DSC-F505银色机身的F717,外形与DSC-F707无甚分别。不过,在机能上则作出了自我增值!

  3. Remote Evaluation of Rotational Velocity Using a Quadrant Photo-Detector and a DSC Algorithm.

    Science.gov (United States)

    Zeng, Xiangkai; Zhu, Zhixiong; Chen, Yang

    2016-04-25

    This paper presents an approach to remotely evaluate the rotational velocity of a measured object by using a quadrant photo-detector and a differential subtraction correlation (DSC) algorithm. The rotational velocity of a rotating object is determined by two temporal-delay numbers at the minima of two DSCs that are derived from the four output signals of the quadrant photo-detector, and the sign of the calculated rotational velocity directly represents the rotational direction. The DSC algorithm does not require any multiplication operations. Experimental calculations were performed to confirm the proposed evaluation method. The calculated rotational velocity, including its amplitude and direction, showed good agreement with the given one, which had an amplitude error of ~0.3%, and had over 1100 times the efficiency of the traditional cross-correlation method in the case of data number N > 4800. The confirmations have shown that the remote evaluation of rotational velocity can be done without any circular division disk, and that it has much fewer error sources, making it simple, accurate and effective for remotely evaluating rotational velocity.

  4. An isothermal titration and differential scanning calorimetry study of the G-quadruplex DNA-insulin interaction.

    Science.gov (United States)

    Timmer, Christine M; Michmerhuizen, Nicole L; Witte, Amanda B; Van Winkle, Margaret; Zhou, Dejian; Sinniah, Kumar

    2014-02-20

    The binding of insulin to the G-quadruplexes formed by the consensus sequence of the insulin-linked polymorphic region (ILPR) was investigated with differential scanning calorimetry (DSC) and isothermal titration calorimetry (ITC). The thermal denaturation temperature of insulin was increased by almost 4 °C upon binding to ILPR G-quadruplex DNA as determined by DSC. The thermodynamic parameters (K(D), ΔH, ΔG, and ΔS) of the insulin-G-quadruplex complex were further investigated by temperature-dependent ITC measurement over the range of 10-37 °C. The binding of insulin to the ILPR consensus sequence displays micromolar affinity in phosphate buffer at pH 7.4, which is mainly driven by entropic factors below 25 °C but by enthalpic terms above 30 °C. The interaction was also examined in several different buffers, and results showed that the observed ΔH is dependent on the ionization enthalpy of the buffer used. This indicates proton release upon the binding of G-quadruplex DNA to insulin. Additionally, the large negative change in heat capacity for this interaction may be associated with the dominant hydrophobicity of the amino acid sequence of insulin's β subunit, which is known to bind to the ILPR G-quadruplex DNA.

  5. Monitoring RNA-ligand interactions using isothermal titration calorimetry.

    Science.gov (United States)

    Gilbert, Sunny D; Batey, Robert T

    2009-01-01

    Isothermal titration calorimetry (ITC) is a biophysical technique that measures the heat evolved or absorbed during a reaction to report the enthalpy, entropy, stoichiometry of binding, and equilibrium association constant. A significant advantage of ITC over other methods is that it can be readily applied to almost any RNA-ligand complex without having to label either molecule and can be performed under a broad range of pH, temperature, and ionic concentrations. During our application of ITC to investigate the thermodynamic details of the interaction of a variety of compounds with the purine riboswitch, we have explored and optimized experimental parameters that yield the most useful and reproducible results for RNAs. In this chapter, we detail this method using the titration of an adenine-binding RNA with 2,6-diaminopurine (DAP) as a practical example. Our insights should be generally applicable to observing the interactions of a broad range of molecules with structured RNAs.

  6. 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.

  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. The glass transition process in humid biopolymers. DSC study

    Energy Technology Data Exchange (ETDEWEB)

    Grunina, N A; Belopolskaya, T V; Tsereteli, G I [V.A. Fock Research Institute for Physics of Saint-Petersburg State University, 198504, Petrodvorets (Russian Federation)

    2006-05-15

    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.

  9. Thermooxidative stability of poppy seeds studied by non-isothermal DSC measurements.

    Science.gov (United States)

    Cibulková, Zuzana; Čertík, Milan; Dubaj, Tibor

    2014-05-01

    Papaver somniferum L. is an important crop cultivated mostly for seed production. Poppy seeds have a high nutritive value and are used as a food and as a source of edible oil. This oil is a rich source of polyunsaturated fatty acids. It is well known that the unsaturated fatty acids easily undergo oxidation reactions, which lead to the reduction of shelf life, nutritional quality, development of unpleasant tastes and odors. The goal of this study was to develop the methodology for testing the stability of poppy seeds using non-isothermal DSC. For the treatment of the experimental data a method based on non-Arrhenian temperature function has been applied and the values the kinetic parameters have been obtained. In order to assess the durability of the commercial poppy seeds, the lengths of induction periods have been calculated.

  10. Characterizing crystal disorder of trospium chloride: a comprehensive,(13) C CP/MAS NMR, DSC, FTIR, and XRPD study.

    Science.gov (United States)

    Urbanova, Martina; Sturcova, Adriana; Brus, Jiri; Benes, Hynek; Skorepova, Eliska; Kratochvil, Bohumil; Cejka, Jan; Sedenkova, Ivana; Kobera, Libor; Policianova, Olivia; Sturc, Antonin

    2013-04-01

    Analysis of C cross-polarization magic angle spinning (CP/MAS) nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR), and X-ray powder diffraction data of trospium chloride (TCl) products crystallized from different mixtures of water-ethanol [φ(EtOH) = 0.5-1.0] at various temperatures (0°C, 20°C) and initial concentrations (saturated solution, 30%-50% excess of solvent) revealed extensive structural variability of TCl. Although (13) C CP/MAS NMR spectra indicated broad variety of structural phases arising from molecular disorder, temperature-modulated DSC identified presence of two distinct components in the products. FTIR spectra revealed alterations in the hydrogen bonding network (ionic hydrogen bond formation), whereas the X-ray diffraction reflected unchanged unit cell parameters. These results were explained by a two-component character of TCl products in which a dominant polymorphic form is accompanied by partly separated nanocrystalline domains of a secondary phase that does not provide clear Bragg reflections. These phases slightly differ in the degree of molecular disorder, in the quality of crystal lattice and hydrogen bonding network. It is also demonstrated that, for the quality control of such complex products, (13) C CP/MAS NMR spectroscopy combined with factor analysis (FA) can satisfactorily be used for categorizing the individual samples: FA of (13) C CP/MAS NMR spectra found clear relationships between the extent of molecular disorder and crystallization conditions. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 102:1235-1248, 2013.

  11. Automatic twin vessel recrystallizer. Effective purification of acetaminophen by successive automatic recrystallization and absolute determination of purity by DSC.

    Science.gov (United States)

    Nara, Osamu

    2011-01-24

    I describe an interchangeable twin vessel (J, N) automatic glass recrystallizer that eliminates the time-consuming recovery and recycling of crystals for repeated recrystallization. The sample goes in the dissolution vessel J containing a magnetic stir-bar K; J is clamped to the upper joint H of recrystallizer body D. Empty crystallization vessel N is clamped to the lower joint M. Pure solvent is delivered to the dissolution vessel and the crystallization vessel via the head of the condenser A. Crystallization vessel is heated (P). The dissolution reservoir is stirred and heated by the solvent vapor (F). Continuous outflow of filtrate E out of J keeps N at a stable boiling temperature. This results in efficient dissolution, evaporation and separation of pure crystals Q. Pure solvent in the dissolution reservoir is recovered by suction. Empty dissolution and crystallization vessels are detached. Stirrer magnet is transferred to the crystallization vessel and the role of the vessels are then reversed. Evacuating mother liquor out of the upper twin vessel, the apparatus unit is ready for the next automatic recrystallization by refilling twin vessels with pure solvent. We show successive automatic recrystallization of acetaminophen from diethyl ether obtaining acetaminophen of higher melting temperatures than USP and JP reference standards by 8× automatic recrystallization, 96% yield at each stage. Also, I demonstrate a novel approach to the determination of absolute purity by combining the successive automatic recrystallization with differential scanning calorimetry (DSC) measurement requiring no reference standards. This involves the measurement of the criterial melting temperature T(0) corresponding to the 100% pure material and quantitative ΔT in DSC based on the van't Hoff law of melting point depression. The purity of six commercial acetaminophen samples and reference standards and an eight times recrystallized product evaluated were 98.8 mol%, 97.9 mol%, 99

  12. 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...

  13. Isothermal Titration Calorimetry to Characterize Enzymatic Reactions.

    Science.gov (United States)

    Mazzei, Luca; Ciurli, Stefano; Zambelli, Barbara

    2016-01-01

    Isothermal titration calorimetry (ITC) is a technique that measures the heat released or absorbed during a chemical reaction as an intrinsic probe to characterize any chemical process that involves heat changes spontaneously occurring during the reaction. The general features of this method to determine the kinetic and thermodynamic parameters of enzymatic reactions (kcat, KM, ΔH) are described and discussed here together with some detailed applications to specific cases. ITC does not require any modification or labeling of the system under analysis, can be performed in solution, and needs only small amounts of enzyme. These properties make ITC an invaluable, powerful, and unique tool to extend the knowledge of enzyme kinetics to drug discovery.

  14. Isothermal Titration Calorimetry of Chiral Polymeric Nanoparticles.

    Science.gov (United States)

    Werber, Liora; Preiss, Laura C; Landfester, Katharina; Muñoz-Espí, Rafael; Mastai, Yitzhak

    2015-09-01

    Chiral polymeric nanoparticles are of prime importance, mainly due to their enantioselective potential, for many applications such as catalysis and chiral separation in chromatography. In this article we report on the preparation of chiral polymeric nanoparticles by miniemulsion polymerization. In addition, we describe the use of isothermal titration calorimetry (ITC) to measure the chiral interactions and the energetics of the adsorption of enantiomers from aqueous solutions onto chiral polymeric nanoparticles. The characterization of chirality in nano-systems is a very challenging task; here, we demonstrate that ITC can be used to accurately determine the thermodynamic parameters associated with the chiral interactions of nanoparticles. The use of ITC to measure the energetics of chiral interactions and recognition at the surfaces of chiral nanoparticles can be applied to other nanoscale chiral systems and can provide further insight into the chiral discrimination processes of nanomaterials.

  15. Calorimetry for Fast Authentication of Edible Oils

    Science.gov (United States)

    Angiuli, Marco; Bussolino, Gian Carlo; Ferrari, Carlo; Matteoli, Enrico; Righetti, Maria Cristina; Salvetti, Giuseppe; Tombari, Elpidio

    2009-06-01

    There are little data in the literature on how to authenticate edible oils through calorimetry techniques. However, oil melting curves can be used to represent correlations between calorimetric results and oil quality. A calorimetric method has been developed for studying the solid-liquid phase transitions of olive oil and seed oils, in which melting peak behavior is correlated to the type, quality, and composition of the oil. Good reproducible thermograms were obtained by defining precise protocols for use in testing, which take into account the specific characteristics of a particular oil. This approach does not replace classical analytical methods; nevertheless, it is believed that calorimetric tests could be a useful preliminary stage for quality testing. The calorimetric technique allows the detection of the adulterant (seed oils or refined olive oil), oil origin, and possible photo-oxidation degradation processes, before more complex and expensive procedures and analyses are applied.

  16. [Study on the Effects of Ginsenoside Rb1 on DPPC Bilayers by Using Thermo-Raman Spectrum and DSC].

    Science.gov (United States)

    Hui, Ge; Liu, Wei; Zhang, Jing-zhou; Zhou, Tie-li; Wang, Si-ming; Zhao, Yu; Zhao, Bing

    2015-08-01

    The research on the interactions between Ginsenosides and biomembranes plays a crucial role in thorough understanding the pharmacological activity and biologyical effect of Chinese medicine Panax ginseng. With the bilayer structure, DPPC often serves as an simulation model of the cell membrane to study the role of drug molecules and cell membranes. Ginsenoside Rb1, one of the most important components of Panaxginseng, playing the significant roles of pharmacological effects and biological properties. Raman and differential scanning calorimetry (DSC) are respectively a powerful tool for discussing the molecular interaction, and a kind of general technology by which researching the bilayer monomer structures and its interactions with drug molecules. However, rarely research reports on the interactions between drug molecules and biomembranes by means of both technologies above. In this paper, the influence of ginsenoside monomer Rb1 on DPPC membrane bilayers was investigated by thermo-Raman and DSC. In Raman spectra, the changes of DPPC molecule have been observed before and after interacted with ginsenoside Rb1, the data analysis indicates three aspects: the O-C-C-N+ polar head group skeleton, C-C stretching vibration area, and the C-H bond stretching vibrarion in terminated methyl group of alkyl chains. The results showed that ginsenoside Rb1 molecule with certain concentration has not changed the gauche conformation of the polar head backbone group in DPPC bilayers, the order of the internal molecular chain and the lateral chain-chain packing have been decreased as the temperature increased, the lateral disposed disorder has been increased. The changes of some thermodynamic constants obtained by DSC experiment such as phase transition temperature (Tm), the temperature at which the transition is half completed (ΔT1/2), and the transition enthalpy normalized per mol of DPPC (AH) have been showed further results of the thermo Raman experiments, with increasing the

  17. Surfactant softening of plant leaf cuticle model wax--a Differential Scanning Calorimetry (DSC) and Quartz Crystal Microbalance with Dissipation (QCM-D) study.

    Science.gov (United States)

    Fagerström, Anton; Kocherbitov, Vitaly; Westbye, Peter; Bergström, Karin; Arnebrant, Thomas; Engblom, Johan

    2014-07-15

    The aim was to quantify the softening effect that two surfactants (C10EO7 and C8G1.6) have on a plant leaf cuticle model wax. Effects on the thermotropic phase behavior and fluidity of the wax (C22H45OH/C32H66/H2O) were determined. The model wax is crystalline at ambient conditions, yet it is clearly softened by the surfactants. Both surfactants decreased the transition temperatures in the wax and the G″/G' ratio of the wax film increased in irreversible steps following surfactant exposure. C10EO7 has a stronger fluidizing effect than C8G1.6 due to stronger interaction with the hydrophobic waxes. Intracuticular waxes (IW) comprise both crystalline and amorphous domains and it has previously been proposed that the fluidizing effects of surfactants are due to interactions with the amorphous parts. New data suggests that this may be a simplification. Surfactants may also absorb in crevices between crystalline domains. This causes an irreversible effect and a softer cuticle wax.

  18. DSC study of denaturation of β-lactoglobulin B

    Institute of Scientific and Technical Information of China (English)

    王邦宁; 谈夫

    1995-01-01

    The denaturation of bovine β-lactoglobulin B (β-Lg B) has been studied in phosphate solutions with various concentrations of GuHCl with differential scanning calorimetry The experiments demonstrated that the presence of GuHCl made the β-Lg B undergo both cold denaturation and heat denaturation under the condition of a high concentration of the protein. The enthalpy changes of both kinds of denaturation exhibit opposite signs. Both the cold denaturation and the renaturation of the protein are reproducible, but its heat denaturation is irreversible. The cooperation among monomer molecules of the protein is involved in its heat denaturation The heat denaturation of the protein can be represented by the thermodynamic model Nc D→F. The activation energy of heat denaturation is 285 kJ/mol, which imples that the depression of temperature and enthalpy of heat denaturation of the P-Lg B does not result from decreasing considerably the activation energy by GuHCl As for the cold denaturation of the protein, es

  19. Application of isothermal titration calorimetry in bioinorganic chemistry.

    Science.gov (United States)

    Grossoehme, Nicholas E; Spuches, Anne M; Wilcox, Dean E

    2010-11-01

    The thermodynamics of metals ions binding to proteins and other biological molecules can be measured with isothermal titration calorimetry (ITC), which quantifies the binding enthalpy (ΔH°) and generates a binding isotherm. A fit of the isotherm provides the binding constant (K), thereby allowing the free energy (ΔG°) and ultimately the entropy (ΔS°) of binding to be determined. The temperature dependence of ΔH° can then provide the change in heat capacity (ΔC (p)°) upon binding. However, ITC measurements of metal binding can be compromised by undesired reactions (e.g., precipitation, hydrolysis, and redox), and generally involve competing equilibria with the buffer and protons, which contribute to the experimental values (K (ITC), ΔH (ITC)). Guidelines and factors that need to be considered for ITC measurements involving metal ions are outlined. A general analysis of the experimental ITC values that accounts for the contributions of metal-buffer speciation and proton competition and provides condition-independent thermodynamic values (K, ΔH°) for metal binding is developed and validated.

  20. 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.

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

    Science.gov (United States)

    You, Mei-Li

    2016-04-28

    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.

  2. Examination of fluorination effect on physical properties of saturated long-chain alcohols by DSC and Langmuir monolayer.

    Science.gov (United States)

    Nakahara, Hiromichi; Nakamura, Shohei; Okahashi, Yoshinori; Kitaguchi, Daisuke; Kawabata, Noritake; Sakamoto, Seiichi; Shibata, Osamu

    2013-02-01

    Partially fluorinated long-chain alcohols have been newly synthesized from a radical reaction, which is followed by a reductive reaction. The fluorinated alcohols have been investigated by differential scanning calorimetry (DSC) and compression isotherms in a Langmuir monolayer state. Their melting points increase with an increase in chain length due to elongation of methylene groups. However, the melting points for the alcohols containing shorter fluorinated moieties are lower than those for the typical hydrogenated fatty alcohols. Using the Langmuir monolayer technique, surface pressure (π)-molecular area (A) and surface potential (ΔV)-A isotherms of monolayers of the fluorinated alcohols have been measured in the temperature range from 281.2 to 303.2K. In addition, a compressibility modulus (Cs(-1)) is calculated from the π-A isotherms. Four kinds of the alcohol monolayers show a phase transition (π(eq)) from a disordered to an ordered state upon lateral compression. The π(eq) values increase linearly with increasing temperatures. A slope of π(eq) against temperature for the alcohols with shorter fluorocarbons is unexpectedly larger than that for the corresponding fatty alcohols. Generally, fluorinated amphiphiles have a greater thermal stability (or resistance), which is a characteristic of highly fluorinated or perfluorinated compounds. Herein, however, the alcohols containing perfluorobutylated and perfluorohexylated chains show the irregular thermal behavior in both the solid and monolayer states.

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

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, Angel V. [UNIPAC Embalagens Ltda., Sao Paulo, SP (Brazil)]. E-mail: angel.ortiz@unipacnet.com; Moura, Esperidiana A.B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)]. E-mail: eabmoura@ipen.br; Coelho, Antonio C.V. [Sao Paulo Univ., SP (Brazil). Escola Politecnica]. E-mail: acvcoelh@usp.br

    2005-07-01

    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)

  4. DSC studies of retrogradation and amylose-lipid complex transition taking place in gamma irradiated wheat starch

    Energy Technology Data Exchange (ETDEWEB)

    Ciesla, K. [Institute of Nuclear Chemistry and Technology, Dorodna 16 str., 03-195 Warsaw (Poland)], E-mail: kciesla@orange.ichtj.waw.pl; Eliasson, A.C. [Department of Food Technology Engineering and Nutrition, Division of Food Technology, University of Lund, P.O. Box 124, S-221 00 Lund (Sweden)

    2007-12-15

    The effect of gamma irradiation ({sup 60}Co) with doses of 5-30 kGy on the amylose-lipid complex transition and retrogradation occurring in gels containing ca. 50% and ca. 20% wheat starch was studied by differential scanning calorimetry (DSC) during heating-cooling-heating cycles (up to three cycles). Transition of the amylose-lipid complex occurs in all the irradiated samples at a lower temperature as compared to the non-irradiated starch. That effect was larger when the radiation dose was higher. A further thermal treatment causes a decrease of the transition temperature in the irradiated samples, with no effect or increase of that temperature observed for the non-irradiated ones. Irradiation hinders retrogradation taking place in 50% gels but facilitates the process occurring in 20% gels. The differences between the irradiated and the non-irradiated samples are more evident in the every next heating or cooling cycle as well as after storage and in the case of ca. 50% suspensions as compared to ca. 20% suspensions. The results point out to the deterioration of the structure of the complexes formed in the irradiated starch as compared to the non-irradiated one.

  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

    Energy Technology Data Exchange (ETDEWEB)

    Buekki-Deme, A.; Alecu, C.G.; Kloppe, B.; Bornschein, B. [Institute of Technical Physics, Tritium Laboratory Karsruhe - TLK, Karlsruhe Institute of Technology - KIT, Karlsruhe (Germany)

    2015-03-15

    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. A thermoreversible double gel: characterization of a methylcellulose and kappa-carrageenan mixed system in water by SAXS, DSC and rheology.

    Science.gov (United States)

    Tomsic, Matija; Prossnigg, Florian; Glatter, Otto

    2008-06-01

    Sol-gel and gel-sol thermal transition of methylcellulose/water, kappa-carrageenan/water and methylcellulose/kappa-carrageenan/water mixtures was investigated utilizing small-angle X-ray scattering (SAXS), differential scanning calorimetry (DSC) and oscillatory rheological experiments in temperature regime from 20 to 80 degrees C. Methylcellulose (E461) and kappa-carrageenan (E407) are well-known additives used for gelation in various nutrition and other products. The formulation and characterization of a mixed thermoreversible methylcellulose/kappa-carrageenan/water gel with very interesting double thermal transition gel-sol-gel upon heating was possible. This specific thermal behavior provides a liquid state of the system between the low-temperature and high-temperature gel-state and at the same time allows for the easy temperature tuning of the system's state. As such this system is suggested to be further tested as potential carrier for various functional colloidal systems.

  8. Determination of Activation Energy of Polymer Molecular Chain by Differential Scanning Calorimetry%DSC用于高聚物分子链迁移活化能的测定

    Institute of Scientific and Technical Information of China (English)

    郭健; 靳新慧; 和涛

    2015-01-01

    本文介绍了差示扫描量热仪 (DSC) 的应用与活化能的定义及其发展, 并利用DSC进行了高聚物分子链迁移活化能的测试, 发现应用DSC测定迁移活化能是较为准确简便的一种方法.%This paper introduce the application of differential scanning calorimetry(DSC),activation energy's definition and development. The author using DHC determine the activation energy of polymer molecular chain. It is found that the applica-tion of DSC in the determination of migration and activation energy is a simple and accurate method.

  9. 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.

  10. The composite reinforcement production in digital manufacturing: experimental validation of the heat transfer and cure modeling results

    Science.gov (United States)

    Kazakov, I.; Krasnovskii, A.; Kutin, A.

    2017-02-01

    The experimental validation of the heat transfer and cure modeling results for 8-mm fiber-reinforced thermosetting composite reinforcement is reported in this article. The temperature and degree of cure of composite reinforcement are predicted using a two-dimensional heat transfer and curing model. The model uses the infrared radiant heating theory and takes into account the heat transfer between the composite rod and the surrounding air. The implicit finite difference method was used to solve the system of governing equations. The results obtained using mathematical model was compared to experimental data: the temperature field inside the composite reinforcement was measured by means of naked thermocouple; Differential Scanning Calorimetry (DSC) was used to measure the degree of cure of the final product. Calculated and measured temperature and degree of cure fields were in good agreement.

  11. 47 CFR 80.359 - Frequencies for digital selective calling (DSC).

    Science.gov (United States)

    2010-10-01

    ... this incorporation by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of this... 47 Telecommunication 5 2010-10-01 2010-10-01 false Frequencies for digital selective calling (DSC... for digital selective calling (DSC). (a) General purpose calling. The following table describes...

  12. 7 CFR 1710.114 - TIER, DSC, OTIER and ODSC requirements.

    Science.gov (United States)

    2010-01-01

    ... substantially in their entirety are in 7 CFR 1717.155. (4) If a distribution borrower has in service or under... 7 Agriculture 11 2010-01-01 2010-01-01 false TIER, DSC, OTIER and ODSC requirements. 1710.114... AND GUARANTEES Loan Purposes and Basic Policies § 1710.114 TIER, DSC, OTIER and ODSC requirements....

  13. 47 CFR 80.103 - Digital selective calling (DSC) operating procedures.

    Science.gov (United States)

    2010-10-01

    ... accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of this standard can be inspected at the Federal... 47 Telecommunication 5 2010-10-01 2010-10-01 false Digital selective calling (DSC) operating... Procedures-General § 80.103 Digital selective calling (DSC) operating procedures. (a) Operating...

  14. 差示扫描量热法在钴盐粘合增进剂热稳定性分析中的应用%Application of DSC in the Thermal Stability Analysis of Cobalt Salt

    Institute of Scientific and Technical Information of China (English)

    高小刚

    2014-01-01

    采用差示扫描量热(DSC)法研究钴盐粘合增进剂硼酰化钴、癸酸钴和硬脂酸钴的热稳定性,用Ozawa方程和Kissinger方程计算活化能。结果表明:根据DSC曲线,用Ozawa方程和Kissinger方程求得的钴盐粘合增进剂的活化能相近,线性相关因数都在0.998以上;3种钴盐粘合增进剂热稳定性从高到低依次为硼酰化钴、癸酸钴、硬脂酸钴。DSC法测定橡胶助剂的热稳定性具有快速、准确和高效的特点。%The thermal stability of several cobalt salts, cobalt boroacylate, cobalt decanoate, cobalt stearate, which were used as adhesion promoter, was investigated by using differential scanning calorimetry (DSC), and the activation energy of thermal degradation was calculated by Ozawa equation and Kissinger equation. By either equation, the linear correlation coefficient was over 0.998, and the calculated result was about the same. The experimental results showed that cobalt boroacylate possessed the highest thermal stability, followed by cobalt decanoate, while cobalt stearate had the lowest thermal stability. This method was fast, accurate and efifcient to determine the thermal stability of rubber additives.

  15. Implementation of DSC model and application for analysis of field pile tests under cyclic loading

    Science.gov (United States)

    Shao, Changming; Desai, Chandra S.

    2000-05-01

    The disturbed state concept (DSC) model, and a new and simplified procedure for unloading and reloading behavior are implemented in a nonlinear finite element procedure for dynamic analysis for coupled response of saturated porous materials. The DSC model is used to characterize the cyclic behavior of saturated clays and clay-steel interfaces. In the DSC, the relative intact (RI) behavior is characterized by using the hierarchical single surface (HISS) plasticity model; and the fully adjusted (FA) behavior is modeled by using the critical state concept. The DSC model is validated with respect to laboratory triaxial tests for clay and shear tests for clay-steel interfaces. The computer procedure is used to predict field behavior of an instrumented pile subjected to cyclic loading. The predictions provide very good correlation with the field data. They also yield improved results compared to those from a HISS model with anisotropic hardening, partly because the DSC model allows for degradation or softening and interface response.

  16. Comparative study of DSC-PWI and 3D-ASL in ischemic stroke patients.

    Science.gov (United States)

    Zhang, Shui-xia; Yao, Yi-hao; Zhang, Shun; Zhu, Wen-jie; Tang, Xiang-yu; Qin, Yuan-yuan; Zhao, Ling-yun; Liu, Cheng-xia; Zhu, Wen-zhen

    2015-12-01

    The purpose of this study was to quantitatively analyze the relationship between three dimensional arterial spin labeling (3D-ASL) and dynamic susceptibility contrast-enhanced perfusion weighted imaging (DSC-PWI) in ischemic stroke patients. Thirty patients with ischemic stroke were included in this study. All subjects underwent routine magnetic resonance imaging scanning, diffusion weighted imaging (DWI), magnetic resonance angiography (MRA), 3D-ASL and DSC-PWI on a 3.0T MR scanner. Regions of interest (ROIs) were drawn on the cerebral blood flow (CBF) maps (derived from ASL) and multi-parametric DSC perfusion maps, and then, the absolute and relative values of ASL-CBF, DSC-derived CBF, and DSC-derived mean transit time (MTT) were calculated. The relationships between ASL and DSC parameters were analyzed using Pearson's correlation analysis. Receiver operative characteristic (ROC) curves were performed to define the thresholds of relative value of ASL-CBF (rASL) that could best predict DSC-CBF reduction and MTT prolongation. Relative ASL better correlated with CBF and MTT in the anterior circulation with the Pearson correlation coefficients (R) values being 0.611 (P1.0 were 75.7%, 89.2% and 87.8% respectively. ASL-CBF map has better linear correlations with DSC-derived parameters (DSC-CBF and MTT) in anterior circulation in ischemic stroke patients. Additionally, when rASL is lower than 0.585, it could predict DSC-CBF decrease with moderate accuracy. If rASL values range from 0.585 to 0.952, we just speculate the prolonged MTT.

  17. 基于DSC的预浸料固化工艺评价和优化%Evaluation and optimization of the prepreg's curing process via DSC analysis

    Institute of Scientific and Technical Information of China (English)

    陶家祥; 李炜

    2016-01-01

    The curing stage of prepreg, as the intermediate matrix composite, directly influence the properties of the finished composite materials when the properties of the composite are determined by the curing process of composite. Differential Scanning Calorimetry(DSC), as a kind of thermal analysis instrument, can measure the heat process of the curing well. This paper mainly introduces the influencing factors when DSC is in use, the determination of curing parameter, the evaluation of the curing process and how to determine, evaluate and opti-mize the curing process by the curing kinetics theory of prepreg.%采用差示扫描量热法(DSC)测量了预浸料固化反应热过程。并对预浸料固化的影响因素、固化参数的确定,以及通过DSC确定预浸料的固化参数对预浸料固化工艺进行评价和通过预浸料固化动力学对预浸料的固化工艺进行优化。

  18. 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...

  19. Characterization of membrane protein interactions by isothermal titration calorimetry.

    Science.gov (United States)

    Situ, Alan J; Schmidt, Thomas; Mazumder, Parichita; Ulmer, Tobias S

    2014-10-23

    Understanding the structure, folding, and interaction of membrane proteins requires experimental tools to quantify the association of transmembrane (TM) helices. Here, we introduce isothermal titration calorimetry (ITC) to measure integrin αIIbβ3 TM complex affinity, to study the consequences of helix-helix preorientation in lipid bilayers, and to examine protein-induced lipid reorganization. Phospholipid bicelles served as membrane mimics. The association of αIIbβ3 proceeded with a free energy change of -4.61±0.04kcal/mol at bicelle conditions where the sampling of random helix-helix orientations leads to complex formation. At bicelle conditions that approach a true bilayer structure in effect, an entropy saving of >1kcal/mol was obtained from helix-helix preorientation. The magnitudes of enthalpy and entropy changes increased distinctly with bicelle dimensions, indicating long-range changes in bicelle lipid properties upon αIIbβ3 TM association. NMR spectroscopy confirmed ITC affinity measurements and revealed αIIbβ3 association and dissociation rates of 4500±100s(-1) and 2.1±0.1s(-1), respectively. Thus, ITC is able to provide comprehensive insight into the interaction of membrane proteins.

  20. Hot biological catalysis: isothermal titration calorimetry to characterize enzymatic reactions.

    Science.gov (United States)

    Mazzei, Luca; Ciurli, Stefano; Zambelli, Barbara

    2014-04-04

    Isothermal titration calorimetry (ITC) is a well-described technique that measures the heat released or absorbed during a chemical reaction, using it as an intrinsic probe to characterize virtually every chemical process. Nowadays, this technique is extensively applied to determine thermodynamic parameters of biomolecular binding equilibria. In addition, ITC has been demonstrated to be able of directly measuring kinetics and thermodynamic parameters (kcat, KM, ΔH) of enzymatic reactions, even though this application is still underexploited. As heat changes spontaneously occur during enzymatic catalysis, ITC does not require any modification or labeling of the system under analysis and can be performed in solution. Moreover, the method needs little amount of material. These properties make ITC an invaluable, powerful and unique tool to study enzyme kinetics in several applications, such as, for example, drug discovery. In this work an experimental ITC-based method to quantify kinetics and thermodynamics of enzymatic reactions is thoroughly described. This method is applied to determine kcat and KM of the enzymatic hydrolysis of urea by Canavalia ensiformis (jack bean) urease. Calculation of intrinsic molar enthalpy (ΔHint) of the reaction is performed. The values thus obtained are consistent with previous data reported in literature, demonstrating the reliability of the methodology.

  1. On the feasibility of water calorimetry with scanned proton radiation.

    Science.gov (United States)

    Sassowsky, M; Pedroni, E

    2005-11-21

    Water calorimetry is considered to be the most direct primary method to realize the physical quantity gray for absorbed dose to water. The Swiss Federal Office of Metrology and Accreditation (METAS) has routinely operated a water calorimeter as primary standard for photon radiation since 2001. Nowadays, cancer therapy with proton radiation has become increasingly important and is a well established method. In the framework of the ProScan project conducted by the Paul Scherrer Institute (PSI), the spot-scanning technique is prepared for the subsequent application in hospitals, and adjusted to the recent findings of clinical research. In the absence of primary standards for proton radiation, the metrological traceability is assured by calibrating secondary standards in 60Co radiation and correcting with calculated beam quality correction factors. It is internationally recognized that the development of primary standards for proton radiation is highly desirable. In a common project of PSI and METAS, it is investigated whether a modified version of the water calorimeter in operation at METAS is suitable as primary standard for scanned proton radiation. A feasibility study has been conducted to investigate the linear energy transfer (LET) dependence of the heat defect and the influence of the time and space structure of the scanned beam on the homogeneity and stability of the temperature field in the water calorimeter. Simulations are validated against experimental data of the existing calorimeter used with photon radiation and extended to scanned proton radiation.

  2. Raman, FTIR, DSC, EPR and optical properties of B2O3-K2O-ZnO-Li2Oglass system doped with Cu2+ ions

    Directory of Open Access Journals (Sweden)

    G. N. Devde

    2015-12-01

    Full Text Available X-ray diffraction (XRD, Raman, Fourier Transform Infrared (FTIR, Differential scanning calorimetry (DSC, Electron paramagnetic resonance (EPR and optical absorption studies on 59B2O3-10K2O-(30-xZnO-xLi2O- 1CuO glasses (where x = 0, 6, 12, 18, 24 and 30 mol% have been carried out. The amorphous nature of the glasses was confirmed using XRD and DSC measurements. The glass transition temperature (Tg of glass samples have been estimated from DSC traces and found that Tg decreases from 488 to 422 oC with the progressive substitution of Li2O content in the place of ZnO content. Almost all of the glass samples in the composition 59B2O3-10K2O-(30-xZnO-xLi2O-1CuO (0 ≤ x ≤ 30 mol% have the thermal stability (ΔT more than 100 oC. The Raman and FTIR studies have been showed that the present glass system consists of [BO3] and [BO4] units in various borate groups. The spin-Hamiltonian parameters (SHP such as g||, g⊥, and A|| have been determined from EPR spectra and it was found that the Cu2+ ion is present in tetragonal distorted octahedral site with x2 - y2 d as the ground state. Bonding parameters and bonding symmetry of Cu2+ ions have been calculated by correlating EPR and optical data and were found to be composition dependent.

  3. Synthesis kinetics of Mg_2Sn in Mg-Sn powder mixture using non-isothermal differential scanning calorimetry

    Institute of Scientific and Technical Information of China (English)

    WU Yu-feng; DU Wen-bo; ZUO Tie-yong

    2009-01-01

    The non-isothermal heating process of Mg-Sn powder mixture was studied by differential scanning calorimetry(DSC) technique and the synthesis kinetics of Mg_2Sn was evaluated by the model-free and model-fitting methods. The activation energy and conversion function of Mg_2Sn synthesis reaction are calculated to be 281.7 kJ/mol and g(α)=[-ln(1-α)]~(1/4), respectively. The reaction mechanism of 2Mg+Sn→Mg_2Sn under non-isothermal condition is regarded as "nucleation and growth". During the non-isothermal heating process, the phase transformation occurred in the Mg-Sn powder mixture was analyzed by XRD and the microstructure evolution of Mg_2Sn was observed by optical microscopy, which is in good agreement with the reaction mechanism of 2Mg+Sn→Mg_2Sn deduced from the kinetic evaluation.

  4. Calorimetry and Langmuir-Blodgett studies on the interaction of a lipophilic prodrug of LHRH with biomembrane models.

    Science.gov (United States)

    Sarpietro, Maria G; Accolla, Maria L; Santoro, Nancy; Mansfeld, Friederike M; Pignatello, Rosario; Toth, Istvan; Castelli, Francesco

    2014-05-01

    The interaction between an amphiphilic luteinizing hormone-releasing hormone (LHRH) prodrug that incorporated a lipoamino acid moiety (C12-LAA) with biological membrane models that consisted of multilamellar liposomes (MLVs) and phospholipid monolayers, was studied using Differential Scanning Calorimetry (DSC) and Langmuir-Blodgett film techniques. The effect of the prodrug C12[Q1]LHRH on the lipid layers was compared with the results obtained with the pure precursors, LHRH and C12-LAA. Conjugation of LHRH with a LAA promoiety showed to improve the peptide interaction with biomembrane models. Basing on the calorimetric findings, the LAA moiety aided the transfer of the prodrug from an aqueous solution to the biomembrane model.

  5. IATC, DSC, and PPC Analysis of Reversible and Multistate Structural Transition of Cytochrome c.

    Science.gov (United States)

    Kidokoro, Shun-ichi; Nakamura, Shigeyoshi

    2016-01-01

    Development of precise calorimeters has enabled us to monitor the structural transition of biomolecules by calorimetry to characterize the thermodynamic property changes accompanying three-dimensional structure change. We developed isothermal acid-titration calorimetry to evaluate the pH dependence of protein enthalpy, and demonstrated the thermodynamic transition between the native and molten globule (MG) states of cytochrome c with very small enthalpy change (~20 kJ/mol) by this method. The double deconvolution method with precise differential scanning calorimetry has revealed the MG state as an equilibrium intermediate state of the reversible thermal transition of the protein, and pressure perturbation calorimetry has succeeded in determining its volumetric properties. These examples strongly indicate the importance of a precise calorimetry and analysis model in the field of protein research.

  6. 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.

  7. Standard Procedure for Calibrating an Areal Calorimetry Based Dosimeter

    Science.gov (United States)

    2015-05-01

    unlimited (P.A. Case No. TSRL-PA-2015-0136, 24 Sep 15). REFERENCES Beason, C. W. (2005). CLT As A Calorimeter. PowerPoint presentation dated 10 January...or sell any patented invention that may relate to them. This report was cleared for public release by the 88th ABW Public Affairs Office and is...is presented for calibrating an areal calorimetry-based dosimeter. A detailed example of calibrating an areal calorimetry-based dosimeter is

  8. 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.

  9. 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.

  10. Insights into the binding of the drugs diclofenac sodium and cefotaxime sodium to serum albumin: calorimetry and spectroscopy.

    Science.gov (United States)

    Sharma, Ruchika; Choudhary, Sinjan; Kishore, Nand

    2012-08-15

    Understanding physical chemistry underlying drug-protein interactions is essential to devise guidelines for the synthesis of target oriented drugs. Binding of a non-steroidal anti-inflammatory drug, diclofenac sodium (DCF) and an antibiotic drug, cefotaxime sodium (CFT) belonging to the family of cephalosporins with bovine serum albumin (BSA) has been examined using a combination of isothermal titration calorimetry (ITC), differential scanning calorimetry (DSC), steady state and time resolved fluorescence and circular dichroism spectroscopies. Binding affinity of both DCF and CFT with BSA is observed to be of the order of 10(4)M(-1), with the binding profiles fitting well to the single set of binding site model. The disagreement between calorimetric and van't Hoff enthalpies indicates non-adherence to a two-state binding process which could be attributed to changes in the conformation of the protein upon ligand binding as well as with increase in the temperature. Circular dichroism and the fluorescence results, however, do not show any major conformational changes upon binding of these drugs to BSA, and hence the discrepancy could be due to temperature induced conformational changes in the protein. The results of ionic strength dependence and binding in the presence of anionic, cationic and non-ionic surfactants indicate, involvement of more that a single type of interaction in the binding process. The ITC results for the binding of these drugs to BSA in presence of each other indicate that the binding sites for the two drugs are different, and therefore binding of one is not influenced by the other. The DSC results provide quantitative information on the effect of these drugs on the stability of serum albumin. The combined calorimetric and spectroscopic approach has provided a detailed analysis including thermodynamics of the binding of DCF and CFT with BSA qualitatively and quantitatively.

  11. 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

  12. 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.

  13. Thermal decomposition study of monovarietal extra virgin olive oil by simultaneous thermogravimetry/differential scanning calorimetry: relation with chemical composition.

    Science.gov (United States)

    Vecchio, Stefano; Cerretani, Lorenzo; Bendini, Alessandra; Chiavaro, Emma

    2009-06-10

    Thermal decomposition of 12 monovarietal extra virgin olive oils from different geographical origins (eight from Italy, two from Spain, and the others from Tunisia) was evaluated by simultaneous thermogravimetry (TG) and differential scanning calorimetry (DSC) analyses. All extra virgin olive oils showed a complex multistep decomposition pattern with the first step that exhibited a quite different profile among samples. Thermal properties of the two peaks obtained by the deconvolution of the first step of decomposition by DSC were related to the chemical composition of the samples (triacylglycerols, fatty acids, total phenols and antioxidant activity). Onset temperatures of the thermal decomposition transition and T(p) values of both deconvoluted peaks as well as the sum of enthalpy were found to exhibit statistically significant correlations with chemical components of the samples, in particular palmitic and oleic acids and related triacylglycerols. Activation energy values of the second deconvoluted peak obtained by the application of kinetic procedure to the first step of decomposition were also found to be highly statistically correlated to the chemical composition, and a stability scale among samples was proposed on the basis of its values.

  14. Application of TZERO calibrated modulated temperature differential scanning calorimetry to characterize model protein formulations.

    Science.gov (United States)

    Badkar, Aniket; Yohannes, Paulos; Banga, Ajay

    2006-02-17

    The objective of this study was to evaluate the feasibility of using T(ZERO) modulated temperature differential scanning calorimetry (MDSC) as a novel technique to characterize protein solutions using lysozyme as a model protein and IgG as a model monoclonal antibody. MDSC involves the application of modulated heating program, along with the standard heating program that enables the separation of overlapping thermal transitions. Although characterization of unfolding transitions for protein solutions requires the application of high sensitive DSC, separation of overlapping transitions like aggregation and other exothermic events may be possible only by use of MDSC. A newer T(ZERO) calibrated MDSC model from TA instruments that has improved sensitivity than previous models was used. MDSC analysis showed total, reversing and non-reversing heat flow signals. Total heat flow signals showed a combination of melting endotherms and overlapping exothermic events. Under the operating conditions used, the melting endotherms were seen in reversing heat flow signal while the exothermic events were seen in non-reversing heat flow signal. This enabled the separation of overlapping thermal transitions, improved data analysis and decreased baseline noise. MDSC was used here for characterization of lysozyme solutions, but its feasibility for characterizing therapeutic protein solutions needs further assessment.

  15. DSC study of cold and heat denaturation processes of β-lactoglobulin A with guanidine hydrochloride

    Institute of Scientific and Technical Information of China (English)

    王邦宁; 谈夫

    1997-01-01

    The cold and heat denaturations of bovine β-lactoglobuhn A (β-lg A) has been studied in solutions of guanidine hydrochloride (GuHCl) by differential scanning calorimelry (DSC) The experimental results are presented and discussed.It is shown that the number of protons bound by the monomeric molecules of β-lg A was unchanged before and after its heat denaturation below pH 3,and that the activation energy of the heat denaturation was depressed owing to the presence of GuHCl.In the solutions with 2.50 and 3.06 mol/L of GuHCl,both the cold and heat denat-urations of β-lg A were observed.In comparison with the heat denaturation,the activation energy of cold denaturation was far lower and the number of GuHCl molecules bound by the unfolded polypeptide chains after cold denaturation increased a lot.The absolute value of the enthalpy of cold denaturation was larger than that of heat denaturation It was found by the analysis that the contribution to the total denaturational enthalpy of conformational change i

  16. Identification of the thermal transitions in potato starch at a low water content as studied by preparative DSC

    NARCIS (Netherlands)

    Steeneken, P.A.M.; Woortman, A.J.J.

    2009-01-01

    The aim of this work was to identify the transitions in the complex DSC profiles of potato starch at a low water content. Preparative DSC involves the thermal processing of samples in stainless steel DSC pans in a way that allows their subsequent structural characterization. The low temperature (LT)

  17. Mathematical model of cycad cones' thermogenic temperature responses: inverse calorimetry to estimate metabolic heating rates.

    Science.gov (United States)

    Roemer, R B; Booth, D; Bhavsar, A A; Walter, G H; Terry, L I

    2012-12-21

    A mathematical model based on conservation of energy has been developed and used to simulate the temperature responses of cones of the Australian cycads Macrozamia lucida and Macrozamia. macleayi during their daily thermogenic cycle. These cones generate diel midday thermogenic temperature increases as large as 12 °C above ambient during their approximately two week pollination period. The cone temperature response model is shown to accurately predict the cones' temperatures over multiple days as based on simulations of experimental results from 28 thermogenic events from 3 different cones, each simulated for either 9 or 10 sequential days. The verified model is then used as the foundation of a new, parameter estimation based technique (termed inverse calorimetry) that estimates the cones' daily metabolic heating rates from temperature measurements alone. The inverse calorimetry technique's predictions of the major features of the cones' thermogenic metabolism compare favorably with the estimates from conventional respirometry (indirect calorimetry). Because the new technique uses only temperature measurements, and does not require measurements of oxygen consumption, it provides a simple, inexpensive and portable complement to conventional respirometry for estimating metabolic heating rates. It thus provides an additional tool to facilitate field and laboratory investigations of the bio-physics of thermogenic plants.

  18. Application of FTIR spectroscopy and differential scanning calorimetry on polypropylene pipe qualitative analysis%红外光谱和差式扫描量热分析在管材级聚丙烯材料定性中的应用

    Institute of Scientific and Technical Information of China (English)

    梁静

    2015-01-01

    本文将从结构与性能的角度出发,以红外光谱法(FTIR)和差式扫描量热法(DSC)测试为手段,详细讨论其在各种管材级聚丙烯材料定性中的应用。%This paper introduced the difference of several pipe’s structures and properties,using Fourier transform infrared spectroscopy(FTIR)and differential scanning calorimetry(DSC),discussed the application of FTIR and DSC on polypropylene pipe qualitative analysis.

  19. Effects of pH and buffer concentration on the thermal stability of etanercept using DSC and DLS.

    Science.gov (United States)

    Kim, Nam Ah; An, In Bok; Lim, Dae Gon; Lim, Jun Yeul; Lee, Sang Yeol; Shim, Woo Sun; Kang, Nae-Gyu; Jeong, Seong Hoon

    2014-01-01

    The protein size, electrical interaction, and conformational stability of etanercept (marketed as Enbrel®) were examined by thermodynamic and light scattering methods with changing pH and buffer concentration. As pH of etanercept increased from pH 6.6 to 8.6, electrical repulsion in the solution increased, inducing a decrease in protein size. However, the size changed less in high buffer concentration and irreversible aggregation issues were not observed; in contrast, aggregates of about 1000 nm were observed in low buffer concentration at the pH range. Three significant unfolding transitions (Tm) were observed by differential scanning calorimetry (DSC). Unlikely to Tm1, Tm2 and Tm3 were increased as the pH increased. Higher Tm at high buffer concentration was observed, indicating increased conformational stability. The apparent activation energy of unfolding was further investigated since continuous increase of Tm2 and Tm3 was not sufficient to determine optimal conditions. A higher energy barrier was calculated at Tm2 than at Tm3. In addition, the energy barriers were the highest at pH from 7.4 to 7.8 where higher Tm1 was also observed. Therefore, the conformational stability of protein solution significantly changed with pH dependent steric repulsion of neighboring protein molecules. An optimized pH range was obtained that satisfied the stability of all three domains. Electrostatic circumstances and structural interactions resulted in irreversible aggregation at low buffer concentrations and were suppressed by increasing the concentration. Therefore, increased buffer concentration is recommended during protein formulation development, even in the earlier stages of investigation, to avoid protein instability issues.

  20. Perfusion calorimetry in the characterization of solvates forming isomorphic desolvates.

    Science.gov (United States)

    Baronsky, Julia; Preu, Martina; Traeubel, Michael; Urbanetz, Nora Anne

    2011-09-18

    In this study, the potential of perfusion calorimetry in the characterization of solvates forming isomorphic desolvates was investigated. Perfusion calorimetry was used to expose different hydrates forming isomorphic desolvates (emodepside hydrates II-IV, erythromycin A dihydrate and spirapril hydrochloride monohydrate) to stepwise increasing relative vapour pressures (RVP) of water and methanol, respectively, while measuring thermal activity. Furthermore, the suitability of perfusion calorimetry to distinguish the transformation of a desolvate into an isomorphic solvate from the adsorption of solvent molecules to crystal surfaces as well as from solvate formation that is accompanied by structural rearrangement was investigated. Changes in the samples were confirmed using FT-Raman and FT-IR spectroscopy. Perfusion calorimetry indicates the transformation of a desolvate into an isomorphic solvate by a substantial exothermic, peak-shaped heat flow curve at low RVP which reflects the rapid incorporation of solvent molecules by the desolvate to fill the structural voids in the lattice. In contrast, adsorption of solvent molecules to crystal surfaces is associated with distinctly smaller heat changes whereas solvate formation accompanied by structural changes is characterized by an elongated heat flow. Hence, perfusion calorimetry is a valuable tool in the characterization of solvates forming isomorphic desolvates which represents a new field of application for the method.

  1. Water absorption of freeze-dried meat at different water activities: a multianalytical approach using sorption isotherm, differential scanning calorimetry, and nuclear magnetic resonance.

    Science.gov (United States)

    Venturi, Luca; Rocculi, Pietro; Cavani, Claudio; Placucci, Giuseppe; Dalla Rosa, Marco; Cremonini, Mauro A

    2007-12-26

    Hydration of freeze-dried chicken breast meat was followed in the water activity range of aw=0.12-0.99 by a multianalytical approach comprising of sorption isotherm, differential scanning calorimetry (DSC), and nuclear magnetic resonance (NMR). The amount of frozen water and the shape of the T2-relaxogram were evaluated at each water content by DSC and NMR, respectively. Data revealed an agreement between sorption isotherm and DSC experiments about the onset of bulk water (aw=0.83-0.86), and NMR detected mobile water starting at aw=0.75. The origin of the short-transverse relaxation time part of the meat NMR signal was also reinvestigated through deuteration experiments and proposed to arise from protons belonging to plasticized matrix structures. It is proved both by D2O experiments and by gravimetry that the extra protons not contributing to the water content in the NMR experiments are about 6.4% of the total proton NMR CPMG signal of meat.

  2. An investigation into the subambient behavior of aqueous mannitol solutions using differential scanning calorimetry, cold stage microscopy, and X-ray diffractometry.

    Science.gov (United States)

    Kett, Vicky L; Fitzpatrick, Shaun; Cooper, Brett; Craig, Duncan Q M

    2003-09-01

    The subambient behavior of aqueous mannitol solutions is of considerable relevance to the preparation of freeze dried formulations. In this investigation the properties of 3% w/v mannitol solutions were investigated using differential scanning calorimetry (DSC), cold stage microscopy (CSM), and X-ray diffraction (XRD) to identify the thermal transitions and structural transformations undergone by this system. It was found that on cooling from ambient the system formed ice at circa -20 degrees C while a further exotherm was seen at approximately -30 degrees C. Upon reheating an endotherm was seen at circa -30 degrees C followed immediately by an exotherm at circa -25 degrees C. Temperature cycling indicated that the thermal transitions observed upon reheating were not reversible. Modulated temperature DSC (MTDSC) indicated that the transitions observed upon reheating corresponded to a glass transition immediately followed by recrystallization, XRD data showed that recrystallization was into the beta form. Annealing at -35 degrees C for 40 min prior to cooling and reheating resulted in a maximum enthalpy being observed for the reheating exotherm. It is concluded that on cooling 3% w/v aqueous mannitol solutions an amorphous phase is formed that subsequently recrystallises into the beta form. The study has also shown that DSC, CSM, and XRD are useful complementary techniques for the study of frozen systems.

  3. 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. ...

  4. 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.

  5. Endoplasmic Reticulum Exit of Golgi-resident Defective for SREBP Cleavage (Dsc) E3 Ligase Complex Requires Its Activity.

    Science.gov (United States)

    Raychaudhuri, Sumana; Espenshade, Peter J

    2015-06-01

    Layers of quality control ensure proper protein folding and complex formation prior to exit from the endoplasmic reticulum. The fission yeast Dsc E3 ligase is a Golgi-localized complex required for sterol regulatory element-binding protein (SREBP) transcription factor activation that shows architectural similarity to endoplasmic reticulum-associated degradation E3 ligases. The Dsc E3 ligase consists of five integral membrane proteins (Dsc1-Dsc5) and functionally interacts with the conserved AAA-ATPase Cdc48. Utilizing an in vitro ubiquitination assay, we demonstrated that Dsc1 has ubiquitin E3 ligase activity that requires the E2 ubiquitin-conjugating enzyme Ubc4. Mutations that specifically block Dsc1-Ubc4 interaction prevent SREBP cleavage, indicating that SREBP activation requires Dsc E3 ligase activity. Surprisingly, Golgi localization of the Dsc E3 ligase complex also requires Dsc1 E3 ligase activity. Analysis of Dsc E3 ligase complex formation, glycosylation, and localization indicated that Dsc1 E3 ligase activity is specifically required for endoplasmic reticulum exit of the complex. These results define enzyme activity-dependent sorting as an autoregulatory mechanism for protein trafficking.

  6. Oxygen Consumption Rate and Energy Expenditure in Mice: Indirect Calorimetry.

    Science.gov (United States)

    Kim, Eun Ran; Tong, Qingchun

    2017-01-01

    Global obesity epidemic demands more effective therapeutic treatments and better understanding of obesity pathophysiology. Since obesity results from energy imbalance, accurate quantification of energy intake and energy expenditure (EE) becomes an essential prerequisite to phenotype the cause for obesity development. Indirect calorimetry has long been used as one of the most established methods in EE quantification by detecting changes in levels of O2 consumption and CO2 production. In this article, we describe procedures and important considerations for an effective measurement using indirect calorimetry.

  7. Characterization of Novel Operation Modes for Secondary Emission Ionization Calorimetry

    Science.gov (United States)

    Tiras, Emrah; Dilsiz, Kamuran; Ogul, Hasan; Snyder, Christina; Bilki, Burak; Onel, Yasar; Winn, David

    2017-01-01

    Secondary Emission (SE) Ionization Calorimetry is a novel technique to measure electromagnetic showers in high radiation environments. We have developed new operation modes by modifying the bias of the conventional PMT circuits. Hamamatsu single anode R7761 and multi-anode R5900-00-M16 Photomultiplier Tubes (PMTs) with modified bases are used as SE detector modules in our SE calorimetry prototype. In this detector module, the first dynode is used as the active media as opposed to photocathode. Here, we report the technical design of new modes and characterization measurements for both SE and PMT modes.

  8. Software solution for control and data acquisition in the pulse calorimetry method

    Directory of Open Access Journals (Sweden)

    Babić Marijana

    2013-01-01

    Full Text Available This work presents a software solution for adjusting, controlling, displaying, and acquiring parameters and data in the pulse calorimetry experimental technique for specific heat capacity, electrical resistivity, total hemispherical emissivity, and normal spectral emissivity measurements. The software has been developed under the LabVIEW platform, V.7.11, and an example of its application with measurement results is presented in a separate section. The total expanded uncertainty of obtained results for the specific heat capacity and electrical resistivity of palladium was 5% and 1 - 2%, respectively.

  9. Impact of sample saturation on the detected porosity of hardened concrete using low temperature calorimetry

    DEFF Research Database (Denmark)

    Wu, Min; Johannesson, Björn

    2014-01-01

    The present work studied the impact of sample saturation on the analysis of pore volume and pore size distribution by low temperature (micro-)calorimetry. The theoretical background was examined, which emphasizes that the freezing/melting temperature of water/ice confined in non-fully saturated...... pores is further depressed compared with that when the pores are fully saturated. The study of the experimental data on hardened concrete samples showed that for a same concrete mix, the total pore volume detected from the capillary saturated samples was always lower than that of the vacuum saturated...

  10. 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.

  11. Yeast SREBP cleavage activation requires the Golgi Dsc E3 ligase complex.

    Science.gov (United States)

    Stewart, Emerson V; Nwosu, Christine C; Tong, Zongtian; Roguev, Assen; Cummins, Timothy D; Kim, Dong-Uk; Hayles, Jacqueline; Park, Han-Oh; Hoe, Kwang-Lae; Powell, David W; Krogan, Nevan J; Espenshade, Peter J

    2011-04-22

    Mammalian lipid homeostasis requires proteolytic activation of membrane-bound sterol regulatory element binding protein (SREBP) transcription factors through sequential action of the Golgi Site-1 and Site-2 proteases. Here we report that while SREBP function is conserved in fungi, fission yeast employs a different mechanism for SREBP cleavage. Using genetics and biochemistry, we identified four genes defective for SREBP cleavage, dsc1-4, encoding components of a transmembrane Golgi E3 ligase complex with structural homology to the Hrd1 E3 ligase complex involved in endoplasmic reticulum-associated degradation. The Dsc complex binds SREBP and cleavage requires components of the ubiquitin-proteasome pathway: the E2-conjugating enzyme Ubc4, the Dsc1 RING E3 ligase, and the proteasome. dsc mutants display conserved aggravating genetic interactions with components of the multivesicular body pathway in fission yeast and budding yeast, which lacks SREBP. Together, these data suggest that the Golgi Dsc E3 ligase complex functions in a post-ER pathway for protein degradation.

  12. 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…

  13. Differential Binding Models for Direct and Reverse Isothermal Titration Calorimetry.

    Science.gov (United States)

    Herrera, Isaac; Winnik, Mitchell A

    2016-03-10

    Isothermal titration calorimetry (ITC) is a technique to measure the stoichiometry and thermodynamics from binding experiments. Identifying an appropriate mathematical model to evaluate titration curves of receptors with multiple sites is challenging, particularly when the stoichiometry or binding mechanism is not available. In a recent theoretical study, we presented a differential binding model (DBM) to study calorimetry titrations independently of the interaction among the binding sites (Herrera, I.; Winnik, M. A. J. Phys. Chem. B 2013, 117, 8659-8672). Here, we build upon our DBM and show its practical application to evaluate calorimetry titrations of receptors with multiple sites independently of the titration direction. Specifically, we present a set of ordinary differential equations (ODEs) with the general form d[S]/dV that can be integrated numerically to calculate the equilibrium concentrations of free and bound species S at every injection step and, subsequently, to evaluate the volume-normalized heat signal (δQ(V) = δq/dV) of direct and reverse calorimetry titrations. Additionally, we identify factors that influence the shape of the titration curve and can be used to optimize the initial concentrations of titrant and analyte. We demonstrate the flexibility of our updated DBM by applying these differentials and a global regression analysis to direct and reverse calorimetric titrations of gadolinium ions with multidentate ligands of increasing denticity, namely, diglycolic acid (DGA), citric acid (CIT), and nitrilotriacetic acid (NTA), and use statistical tests to validate the stoichiometries for the metal-ligand pairs studied.

  14. A study of ultra-strength polymer fibers via calorimetry

    Science.gov (United States)

    Egorov, V. M.; Boiko, Yu. M.; Marikhin, V. A.; Myasnikova, L. P.; Radovanova, E. I.

    2016-08-01

    Xerogel reactor powders and supramolecular polyethylene fibers with various degrees of hood have been studied via differential scanning calorimetry. A higher strength of laboratory fibers in comparison with industrial ones is found to be achieved due to a multistage band high-temperature hood that causes the thermodynamic parameters of supramolecular polymer structure.

  15. Estimation of the Kinetic Parameters and the Critical Rate of Temperature Rise in the Thermal Explosion from the Exothermic Autocatalytic Decomposition of 3,4-Bis(4′-nitrofurazan-3′-yl)-2-oxofurazan (BNFOF) Using Non-isothermal Differential Scanning Calorimetry

    Institute of Scientific and Technical Information of China (English)

    ZHAO Feng-Qi; ZHOU Yan-Shui; ZHAO Hong-An; GAO Sheng-Li; SHI Qi-Zhen; LU Gui-E; JIANG Jin-Yong; GUO Peng-Jiang; HU Rong-Zu; ZHANG Hai; XIA Zhi-Ming; GAO Hong-Xu; CHEN Pei; LUO Yang; ZHANG Zhi-Zhong

    2006-01-01

    A method of estimating the kinetic parameters and the critical rate of temperature rise in the thermal explosion for the autocatalytic decomposition of 3,4-bis(4′-nitrofurazan-3′-yl)-2-oxofurazan (BNFOF) with non-isothermal differential scanning calorimetry (DSC) was presented. The rate equation for the decomposition of BNFOF was established, and information was obtained on the rate of temperature increase in BNFOF when the empiric-order autocatalytic decomposition was converted into thermal explosion.

  16. Characterization of pegylated liposomal mitomycin C lipid-based prodrug (Promitil®) by high sensitivity differential scanning calorimetry and cryogenic transmission electron microscopy.

    Science.gov (United States)

    Wei, Xiaohui; Patil, Yogita; Ohana, Patricia; Amitay, Yasmine; Shmeeda, Hilary; Gabizon, Alberto; Barenholz, Yechezkel

    2017-01-03

    The effect of a lipidated prodrug of mitomycin C (MLP) on the membrane of a pegylated liposome formulation (PL-MLP), also known as Promitil®, was characterized through high-sensitivity differential scanning calorimetry (DSC), and cryo-TEM. The thermodynamic analysis demonstrated that MLP led to the formation of heterogeneous domains in the membrane plane of PL-MLP. MLP concentrated in prodrug-rich domains, arranged in high-ordered crystal-like structures, as suggested by the sharp and high enthalpy endotherm in the 1st heating scanning. After thiolytic cleavage of mitomycin C from MLP by dithiotreitol (DTT) treatment, the crystal-like prodrug domain disappears and a homogeneous membrane with stronger lipid interactions and higher phase transition temperature compared with the blank (MLP-free) liposomes is observed by DSC. In parallel, the rod-like discoid liposomes and the "kissing liposomes" seen by cryo-TEM in the PL-MLP formulation disappear, and liposome mean size and polydispersity increase after DTT treatment. Both MLP and the residual post-cleavage lipophilic moiety of the prodrug increased rigidity of the liposome membrane as indicated by DSC. These results confirm that MLP is inserted in the PL-MLP liposome membrane via its lipophilic anchor, and its mitomycin C moiety located mainly at the region of the phospholipid glycerol backbone and polar head-group. We hypothesize that Π-Π stacking between the planar aromatic rings of the mitomycin C moieties leads to the formation of prodrug-rich domains with highly ordered structure on the PL-MLP liposome membrane. This thermodynamically stable conformation may explain the high stability of the PL-MLP formulation. These results also provide us with an interesting example of the application of high sensitivity DSC in understanding the composition-structure-behavior dynamics of liposomal nanocarriers having a lipid-based drug as pharmaceutical ingredient.

  17. Comparative SAXS and DSC study on stratum corneum structural organization in an epidermal cell culture model (ROC): impact of cultivation time.

    Science.gov (United States)

    Kuntsche, Judith; Herre, Angela; Fahr, Alfred; Funari, Sérgio S; Garidel, Patrick

    2013-12-18

    Cell cultured skin equivalents present an alternative for dermatological in vitro evaluations of drugs and excipients as they provide the advantage of availability, lower variability and higher assay robustness compared to native skin. For penetration/permeation studies, an adequate stratum corneum barrier similar to that of human stratum corneum is, however, a prerequisite. In this study, the stratum corneum lipid organization in an epidermal cell culture model based on rat epidermal keratinocytes (REK organotypic culture, ROC) was investigated by small-angle X-ray scattering (SAXS) in dependence on ROC cultivation time and in comparison to native human and rat stratum cornea. In addition, the thermal phase behavior was studied by differential scanning calorimetry (DSC) and barrier properties were checked by measurements of the permeability of tritiated water. The development of the barrier of ROC SC obtained at different cultivation times (7, 14 and 21 days at the air-liquid interface) was connected with an increase in structural order of the SC lipids in SAXS measurements: Already cultivation for 14 days at the air-liquid interface resulted overall in a competent SC permeability barrier and SC lipid organization. Cultivation for 21 days resulted in further minor changes in the structural organization of ROC SC. The SAXS patterns of ROC SC had overall large similarities with that of human SC and point to the presence of a long periodicity phase with a repeat distance of about 122Å, e.g. slightly smaller than that determined for human SC in the present study (127Å). Moreover, SAXS results also indicate the presence of covalently bound ceramides, which are crucial for a proper SC barrier, although the corresponding thermal transitions were not clearly detectable by DSC. Due to the competent SC barrier properties and high structural and organizational similarity to that of native human SC, ROC presents a promising alternative for in vitro studies, particularly as

  18. What does calorimetry and thermodynamics of living cells tell us?

    Science.gov (United States)

    Maskow, Thomas; Paufler, Sven

    2015-04-01

    This article presents and compares several thermodynamic methods for the quantitative interpretation of data from calorimetric measurements. Heat generation and absorption are universal features of microbial growth and product formation as well as of cell cultures from animals, plants and insects. The heat production rate reflects metabolic changes in real time and is measurable on-line. The detection limit of commercially available calorimetric instruments can be low enough to measure the heat of 100,000 aerobically growing bacteria or of 100 myocardial cells. Heat can be monitored in reaction vessels ranging from a few nanoliters up to many cubic meters. Most important the heat flux measurement does not interfere with the biological process under investigation. The practical advantages of calorimetry include the waiver of labeling and reactants. It is further possible to assemble the thermal transducer in a protected way that reduces aging and thereby signal drifts. Calorimetry works with optically opaque solutions. All of these advantages make calorimetry an interesting method for many applications in medicine, environmental sciences, ecology, biochemistry and biotechnology, just to mention a few. However, in many cases the heat signal is merely used to monitor biological processes but only rarely to quantitatively interpret the data. Therefore, a significant proportion of the information potential of calorimetry remains unutilized. To fill this information gap and to motivate the reader using the full information potential of calorimetry, various methods for quantitative data interpretations are presented, evaluated and compared with each other. Possible errors of interpretation and limitations of quantitative data analysis are also discussed.

  19. 更胜一筹:Sony DSC-H20

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Sony DSC-H20是H10的后续版本,相比之下新款相机的像素值提高至1010万像素,具备720P、1280×720、30fps高画质录像能力.搭载3英寸、23万像素LCD屏幕。DSC-H20支持双重防抖功能,相机采用10倍光学变焦镜头.

  20. Differential scanning calorimetry study of glass transition in frozen starch gels.

    Science.gov (United States)

    Tananuwong, Kanitha; Reid, David S

    2004-06-30

    The effects of initial water content, maximum heating temperature, amylopectin crystallinity type, and annealing on the glass transition of starch gels were studied by differential scanning calorimetry (DSC). The glass transition temperatures of the frozen gels measured as the onset (T(g,onset)) or midpoint temperature (T(g,midpoint)), heat capacity change during the glass transition (deltaC(p)), unfrozen water of starch gels, and additional unfrozen water (AUW) arising from gelatinization were reported. The results show that T(g,onset) and T(g,midpoint) of the partially gelatinized gels are independent of the initial water content, while both of the T(g) values of the fully gelatinized gel increase as the initial water content increases. These observations might result from the difference in the level of structural disruption associated with different heating conditions, resulting in different gel structures as well as different concentrations of the sub-T(g) unfrozen matrix. The amylopectin crystallinity type does not greatly affect T(g,onset) and T(g,midpoint) of the gels. Annealing at a temperature near T(g,onset) increases both T(g,onset) and T(g,midpoint) of the gels, possibly due to an increase in the extent of the freeze concentration as evidenced by a decrease in AUW. Annealing results in an increase in the deltaC(p) value of the gels, presumably due to structural relaxation. A devitrification exotherm may be related to AUW. The annealing process decreases AUW, thus also decreasing the size of the exotherm.

  1. Vibrational spectroscopic, optical and thermal properties of a hybride pyridazine perchlorate complex-An experimental and theoretical study

    Science.gov (United States)

    Podsiadła, D.; Czupiński, O.; Rospenk, M.; Czapla, Z.

    2016-12-01

    Various methods of experiment: differential scanning calorimetry (DSC), differential thermal analysis (DTA), thermogravimetric analysis (TGA) and infrared (IR) spectroscopy have been used to investigate the phase transitions in pyridazine perchlorate crystal. DSC showed the existence of phase transition at T = 341 K. The vibrational IR spectra in Nujol and Perfluorolube mulls were studied in a wide temperature range, from room temperature to 380 K. Special attention was put on the temperatures near the phase transition temperature. The temperature changes of wavenumbers, gravity center and band intensities were analyzed to clarify the phase transition molecular mechanism. Information about hydrogen bonds was obtained. For more detailed band assignment and overall spectral presentation Raman and far infrared (FT-FIR) spectra at room temperature have been carried out. The experimental data interpretation was supported by theoretical calculations based on density functional theory, with the B3LYP method and 6-311++G(d,p) basic set. Some theoretical conformations were analyzed. Calculated normal vibrational modes of the molecule, their frequencies and intensities were compared with these recorded in experiment.

  2. 触,爱 SONY DSC-T2索尼数码相机

    Institute of Scientific and Technical Information of China (English)

    邢瑜

    2007-01-01

    索尼DSC-T2数码相机是DSC-T1的升级产品.与DSC-T1相比.要小巧秀气了许多.在没有打开镜头的时候,很多人都会误以为它是一个播放器或是小首饰盒之类的物件,无意中DSC-T2迷惑了众人的眼睛。

  3. DSC 法研究高能炸药 TEX 与推进剂组分的相容性%Compatibility of High Energetic Explosive TEX with Components of Propellants by DSC Method

    Institute of Scientific and Technical Information of China (English)

    王瑞; 孟子晖; 薛敏; 徐志斌; 崔可建; 赵凤起; 肖立柏; 郭琪

    2015-01-01

    采用差示扫描量热法(DSC)研究了4,10-二硝基-2,6,8,12-四氧杂-4,10-二氮杂四环[5,5,0,05,9,03,11]十二烷(TEX)与黑索今(RDX)、吉纳(DINA)、硝化棉(NC)、吸收药(NC+NG)、苯二甲酸二乙酯(DEP)、邻苯二甲酸铅(Φ-Pb)和微米级铝粉(Al)等推进剂主要组分的热分解性能,并考察了 TEX 与7种组分的相容性。结果表明, TEX 的热稳定性较好,与 RDX、Φ-Pb、NC、DINA 和 Al 粉的相容性良好,与 NC+NG 和 DEP 轻微敏感、相容性较好,可应用于推进剂等含能材料领域中。%The thermal decomposition performance and compatibility of 4,10-dinitro-2,6,8,12-tatraoxa-4, 10-diazatatracyclo [5,5,0,05 ,9 ,03 ,11 ]-decane (TEX)with main components of propellants such as cyclotrimethylene-trinitramine(RDX),N-nitrodihydroxyethylaminedinitrate (DINA),nitrocellulose (NC),absorbentia (NC + NG), diethylphthalate(DEP),leadphthalate(Φ-Pb)and aluminium powder (micron order)were studied by differential scanning calorimetry(DSC).The results show that TEX is relatively stable to heat,the binary system of TEX was compatible with RDX,Φ-Pb,NC,DINA and aluminium powder,and was slightly sensitive with absorbentia(NC+NG)and NC.Thus TEX can be used as component in propellants.

  4. Brain Metastases from Different Primary Carcinomas: an Evaluation of DSC MRI Measurements.

    Science.gov (United States)

    Zhang, H; Zhang, G; Oudkerk, M

    2012-03-01

    This study evaluated the roles of different dynamic susceptibility contrast magnetic imaging (DSC MRI) measurements in discriminating between brain metastases derived from four common primary carcinomas. Thirty-seven patients with brain metastases were enrolled. Relative cerebral blood volume (rCBV), cerebral blood flow (rCBF) and relative mean transit time (rMTT) in both tumor and peritumoral edema were measured. Metastases were grouped by their primary tumor (lung, gastrointestinal, breast and renal cell carcinoma). DSC MRI measurements were compared between groups. Mean rCBV, rCBF, rMTT in tumor and peritumoral edema of all brain metastases (n=37) were 2.79 ± 1.73, 2.56 ± 2.11, 1.21 ± 0.48 and 1.05 ± 0.53, 0.86 ± 0.40, 1.99 ± 0.41, respectively. The tumoral rCBV (5.26 ± 1.89) and rCBF (5.32 ± 3.28) of renal metastases were greater than those of the other three metastases (P0.05). Evaluating various DSC MRI measurements can provide complementary hemodynamic information on brain metastases. The tumoral rCBV, rCBF and likely rMTT can help discriminate between brain metastases originating from different primary carcinomas. The peritumoral DSC MRI measurements had limited value in discriminating between brain metastases.

  5. Rapid examination of the kinetic process of intramolecular lactamization of gabapentin using DSC-FTIR

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, C.-H. [Lab. Pharm. Biopharm., Department of Biotechnology, Yuanpei University, Hsin Chu, Taiwan (China); Lin, S.-Y. [Lab. Pharm. Biopharm., Department of Biotechnology, Yuanpei University, Hsin Chu, Taiwan (China)], E-mail: sylin@mail.ypu.edu.tw

    2009-03-20

    The thermal stability and thermodynamics of gabapentin (GBP) in the solid state were investigated by DSC and TG techniques, and FTIR microspectroscopy. The detailed intramolecular lactamization process of GBP to form gabapentin-lactam (GBP-L) was also determined by thermal FTIR microspectroscopy. GBP exhibited a DSC endothermic peak at 169 deg. C. The weight loss in TG curve of GBP suggested that the evaporation process of water liberated via intramolecular lactamization was simultaneously combined with the evaporation process of GBP-L having a DSC endothermic peak at 91 deg. C. A thermal FTIR microspectroscopy clearly evidenced the IR spectra at 3350 cm{sup -1} for water liberated and at 1701 cm{sup -1} for lactam structure formed due to the lactam formation of GBP. This study indicates that the activation energy for combined processes of intramolecular lactamization of GBP and evaporation of GBP-L was about 114.3 {+-} 23.3 kJ/mol, but for the evaporation of GBP-L alone was 76.2 {+-} 1.5 kJ/mol. A powerful simultaneous DSC-FTIR combined technique was easily used to quickly examine the detailed kinetic processes of intramolecular cyclization of GPB and evaporation of GBP-L in the solid state.

  6. 差示扫描量热法评价聚山梨酯80质量%Quality Evaluation of Polysorbate 80 by a Differential Scanning Calorimetry

    Institute of Scientific and Technical Information of China (English)

    韩荣; 李蒙; 张海燕; 齐云; 杨明; 廖永红

    2011-01-01

    Objective To investigate the applicability of differential scanning calorimetry ( DSC ) to evaluate the quality of polysorbate 80. Methods Eight different brands of polysorbate 80 were characterized by DSC, and the melting points and peak shape of polysorbate 80 were analyzed. The hemolysis of rabbit in vitro induced by polysorbate 80 was determined with ELISA at 540 nm, whilst the muscle irritation was tested by using creatine kinase ( CK ) kit following exposure of L6 cells with polysorbate 80. Results DSC thermograms showed an excellent reproducibility for the same brand and same batch of polysorbate 80 with the RSD of melting points within 5%. In addition, they were sensitive and distinguished difference between batches or brands of polysorbate 80. DSC thermograms was directly related to the quality. Different batches of polysorbate 80 presented different DSC thermograms, demonstrating differences within constituents of samples, which was confirmed by the results of hemolysis and muscle irritation. Conclusion DSC has the potential to be utilized as a semi-quantitative means for the quality evaluation of polysorbate 80.%目的 研究差示扫描量热法(differential scanning calorimetry,DSC)作为聚山梨酯80质量评价方法的可行性.方法 采用DSC对8个不同品牌的聚山梨酯80进行表征,分析DSC图谱中熔点和峰型;采用酶标法测定聚山梨酯80对家兔体外溶血的影响;采用肌酸激酶(creatine kinase,CK)试剂盒测定聚山梨酯80对L6细胞的刺激性.结果 同一品牌同一批聚山梨酯80熔点相对标准偏差(relative standard deviation,RSD)在5%以内,重复性良好.DSC热分析图具有较好的灵敏度,可甄别批次间成分存在的一定差异.DSC热分析图的差异和品质有直接的相关性,不同品牌的聚山梨酯80呈现差异较大的热分析图,表明这些样品成分差异较大,这一结果得到了体外溶血性和骨骼肌刺激性实验结果的证实.结论 DSC

  7. The Simulation of the ATLAS Liquid Argon Calorimetry

    CERN Document Server

    Archambault, J P; Carli, T; Costanzo, D; Dell'Acqua, A; Djama, F; Gallas, M; Fincke-Keeler, M; Khakzad, M; Kiryunin, A; Krieger, P; Leltchouk, M; Loch, P; Ma, H; Menke, S; Monnier, E; Nairz, A; Niess, V; Oakham, G; Oram, C; Pospelov, G; Rajagopalan, S; Rimoldi, A; Rousseau, D; Rutherfoord, J; Seligman, W; Soukharev, A; Strízenec, P; Tóth, J; Tsukerman, I; Tsulaia, V; Unal, G; Grahn, K J

    2008-01-01

    In ATLAS, all of the electromagnetic calorimetry and part of the hadronic calorimetry is performed by a calorimeter system using liquid argon as the active material, together with various types of absorbers. The liquid argon calorimeter consists of four subsystems: the electromagnetic barrel and endcap accordion calorimeters; the hadronic endcap calorimeters, and the forward calorimeters. A very accurate geometrical description of these calorimeters is used as input to the Geant 4-based ATLAS simulation, and a careful modelling of the signal development is applied in the generation of hits. Certain types of Monte Carlo truth information ("Calibration Hits") may, additionally, be recorded for calorimeter cells as well as for dead material. This note is a comprehensive reference describing the simulation of the four liquid argon calorimeteter components.

  8. 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.

  9. 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.

  10. Distinct roles of the DmNav and DSC1 channels in the action of DDT and pyrethroids.

    Science.gov (United States)

    Rinkevich, Frank D; Du, Yuzhe; Tolinski, Josh; Ueda, Atsushi; Wu, Chun-Fang; Zhorov, Boris S; Dong, Ke

    2015-03-01

    Voltage-gated sodium channels (Nav channels) are critical for electrical signaling in the nervous system and are the primary targets of the insecticides DDT and pyrethroids. In Drosophila melanogaster, besides the canonical Nav channel, Para (also called DmNav), there is a sodium channel-like cation channel called DSC1 (Drosophila sodium channel 1). Temperature-sensitive paralytic mutations in DmNav (para(ts)) confer resistance to DDT and pyrethroids, whereas DSC1 knockout flies exhibit enhanced sensitivity to pyrethroids. To further define the roles and interaction of DmNav and DSC1 channels in DDT and pyrethroid neurotoxicology, we generated a DmNav/DSC1 double mutant line by introducing a para(ts1) allele (carrying the I265N mutation) into a DSC1 knockout line. We confirmed that the I265N mutation reduced the sensitivity to two pyrethroids, permethrin and deltamethrin of a DmNav variant expressed in Xenopus oocytes. Computer modeling predicts that the I265N mutation confers pyrethroid resistance by allosterically altering the second pyrethroid receptor site on the DmNav channel. Furthermore, we found that I265N-mediated pyrethroid resistance in para(ts1) mutant flies was almost completely abolished in para(ts1);DSC1(-/-) double mutant flies. Unexpectedly, however, the DSC1 knockout flies were less sensitive to DDT, compared to the control flies (w(1118A)), and the para(ts1);DSC1(-/-) double mutant flies were even more resistant to DDT compared to the DSC1 knockout or para(ts1) mutant. Our findings revealed distinct roles of the DmNav and DSC1 channels in the neurotoxicology of DDT vs. pyrethroids and implicate the exciting possibility of using DSC1 channel blockers or modifiers in the management of pyrethroid resistance.

  11. DSC-Analysis of thermomechanically treated TiNi shape memory alloy

    NARCIS (Netherlands)

    Beyer, J.; Besselink, P.A.; Aartsen, A.J.

    1985-01-01

    The martensitic transformation behaviour, after thermomechanical treatment of the TiNi-alloy with two-way shape memory, have been studied by differential scanning calorimetry. The results are correlated with electrical resistivity and electron microscopical observations. One heating and cooling cycl

  12. Benchmark Thermochemistry for Biologically Relevant Adenine and Cytosine. A Combined Experimental and Theoretical Study.

    Science.gov (United States)

    Emel'yanenko, Vladimir N; Zaitsau, Dzmitry H; Shoifet, Evgeni; Meurer, Florian; Verevkin, Sergey P; Schick, Christoph; Held, Christoph

    2015-09-17

    The thermochemical properties available in the literature for adenine and cytosine are in disarray. A new condensed phase standard (p° = 0.1 MPa) molar enthalpy of formation at T = 298.15 K was measured by using combustion calorimetry. New molar enthalpies of sublimation were derived from the temperature dependence of vapor pressure measured by transpiration and by the quarz-crystal microbalance technique. The heat capacities of crystalline adenine and cytosine were measured by temperature-modulated DSC. Thermodynamic data on adenine and cytosine available in the literature were collected, evaluated, and combined with our experimental results. Thus, the evaluated collection of data together with the new experimental results reported here has helped to resolve contradictions in the available enthalpies of formation. A set of reliable thermochemical data is recommended for adenine and cytosine for further thermochemical calculations. Quantum-chemical calculations of the gas phase molar enthalpies of formation of adenine and cytosine have been performed by using the G4 method and results were in excellent agreement with the recommended experimental data. The standard molar entropies of formation and the standard molar Gibbs functions of formation in crystal and gas state have been calculated. Experimental vapor-pressure data measured in this work were used to estimate pure-component PC-SAFT parameters. This allowed modeling solubility of adenine and cytosine in water over the temperature interval 278-310 K.

  13. 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.

  14. Thermal expansivities of peptides, polypeptides and proteins as measured by pressure perturbation calorimetry.

    Science.gov (United States)

    Pandharipande, Pranav P; Makhatadze, George I

    2015-04-01

    The main goal of this work was to provide direct experimental evidence that the expansivity of peptides, polypeptides and proteins as measured by pressure perturbation calorimetry (PPC), can serve as a proxy to characterize relative compactness of proteins, especially the denatured state ensemble. This is very important as currently only small angle X-ray scattering (SAXS), intrinsic viscosity and, to a lesser degree, fluorescence resonance transfer (FRET) experiments are capable of reporting on the compactness of denatured state ensembles. We combined the expansivity measurements with other biophysical methods (far-UV circular dichroism spectroscopy, differential scanning calorimetry, and small angle X-ray scattering). Three case studies of the effects of conformational changes on the expansivity of polypeptides in solution are presented. We have shown that expansivity appears to be insensitive to the helix-coil transition, and appears to reflect the changes in hydration of the side-chains. We also observed that the expansivity is sensitive to the global conformation of the polypeptide chain and thus can be potentially used to probe hydration of different collapsed states of denatured or even intrinsically disordered proteins.

  15. 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.

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

    Science.gov (United States)

    Xiao, Kechao; Lee, Dongwoo; Vlassak, Joost J.

    2014-10-01

    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. 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.

  18. 鼻咽癌放射治疗后“正常脑白质”的DTI及DSC-PWI研究%DTI and DSC-PWI on normal appearing white matter after radiotherapy for nasopharyngeal carcinoma

    Institute of Scientific and Technical Information of China (English)

    冯霞; 邱士军

    2013-01-01

    Objective To detect the changes of temporal lobes white mater after radiation therapy (RT) for nasopharyngeal carcinoma (NPC) using diffusion tensor imaging (DTI) and dynamic susceptibility contrast-enhanced perfusion-weighted imaging (DSC-PWI).Methods The study included 32 subjects,who had or had not undergone radiotherapy for nasopharyngeal carcinoma of these,16 were pre-treatment patients; the remaining 16 were post-radiation patients.The pre-radiation subjects constituted the control group.The post-radiation patients,who had undergone radiation therapy less than 6 months prior,representing an acute response in the early period after radiation therapy,were the experimental group.There were no statistically significant differences between the groups with respect to age,gender,duration of education,cigarette smoking or alcohol consumption.DTI and DSC-PWI were performed for each subject.After data post-processing,the mean fractional anisotropy (FA),axial diffusivity (λ |),radial diffusivity (λ⊥) and relative celebral blood flow (rCBF) were calculated in bilateral temporal lobe.To find the layer of cerebral peduncle,one ROI was then marked on unilateral temporal lobe white matter in each subject.These ROIs were of equal area.The average of these values in the temporal lobes white matter was accepted as the final value.For all the data,two-sample t-test was performed.Results FA value and λ| decreased significantly in the post-radiation group compared to the pre-radiation group; λ⊥ increased significantly in the post-radiation group compared to the pre-radiation group; rCBF decreased significantly in the post-radiation group compared to the pre-radiation group.Conclusion The results of the present study illustrated micro injury of nerve tissue and blood vessel can be detected by DTI and DSC-PWI.Vascular damage and the resulting decrease in blood flow may participant in neural tissue injury in the early stage after radiotherapy.%目的 探讨鼻咽癌放

  19. Fluence correction factor for graphite calorimetry in a clinical high-energy carbon-ion beam

    Science.gov (United States)

    Lourenço, A.; Thomas, R.; Homer, M.; Bouchard, H.; Rossomme, S.; Renaud, J.; Kanai, T.; Royle, G.; Palmans, H.

    2017-04-01

    The aim of this work is to develop and adapt a formalism to determine absorbed dose to water from graphite calorimetry measurements in carbon-ion beams. Fluence correction factors, {{k}\\text{fl}} , needed when using a graphite calorimeter to derive dose to water, were determined in a clinical high-energy carbon-ion beam. Measurements were performed in a 290 MeV/n carbon-ion beam with a field size of 11  ×  11 cm2, without modulation. In order to sample the beam, a plane-parallel Roos ionization chamber was chosen for its small collecting volume in comparison with the field size. Experimental information on fluence corrections was obtained from depth-dose measurements in water. This procedure was repeated with graphite plates in front of the water phantom. Fluence corrections were also obtained with Monte Carlo simulations through the implementation of three methods based on (i) the fluence distributions differential in energy, (ii) a ratio of calculated doses in water and graphite at equivalent depths and (iii) simulations of the experimental setup. The {{k}\\text{fl}} term increased in depth from 1.00 at the entrance toward 1.02 at a depth near the Bragg peak, and the average difference between experimental and numerical simulations was about 0.13%. Compared to proton beams, there was no reduction of the {{k}\\text{fl}} due to alpha particles because the secondary particle spectrum is dominated by projectile fragmentation. By developing a practical dose conversion technique, this work contributes to improving the determination of absolute dose to water from graphite calorimetry in carbon-ion beams.

  20. 索尼DSC-S85数码相机试用记

    Institute of Scientific and Technical Information of China (English)

    杨明

    2003-01-01

    @@ Cyber-shot DSC-S85是索尼公司于2001年推出的第一款410万像素Super HAD CCD的数码照相机,但其太传统化的外形设计,几度要毁掉我购买它的信心,不过最终还是把它抱回家,因为是它的品质打动我.

  1. Classification of tumor area using combined DCE and DSC MRI in patients with glioblastoma.

    Science.gov (United States)

    Artzi, Moran; Blumenthal, Deborah T; Bokstein, Felix; Nadav, Guy; Liberman, Gilad; Aizenstein, Orna; Ben Bashat, Dafna

    2015-01-01

    This study proposes an automatic method for identification and quantification of different tissue components: the non-enhanced infiltrative tumor, vasogenic edema and enhanced tumor areas, at the subject level, in patients with glioblastoma (GB) based on dynamic contrast enhancement (DCE) and dynamic susceptibility contrast (DSC) MRI. Nineteen MR data sets, obtained from 12 patients with GB, were included. Seven patients were scanned before and 8 weeks following bevacizumab initiation. Segmentation of the tumor area was performed based on the temporal data of DCE and DSC at the group-level using k-means algorithm, and further at the subject-level using support vector machines algorithm. The obtained components were associated to different tissues types based on their temporal characteristics, calculated perfusion and permeability values and MR-spectroscopy. The method enabled the segmentation of the tumor area into the enhancing permeable component; the non-enhancing hypoperfused component, associated with vasogenic edema; and the non-enhancing hyperperfused component, associated with infiltrative tumor. Good agreement was obtained between the group-level, unsupervised and subject-level, supervised classification results, with significant correlation (r = 0.93, p DSC can be used to differentiate between vasogenic edema and infiltrative tumors in patients with GB, which is of major clinical importance in therapy response assessment.

  2. Yeast sterol regulatory element-binding protein (SREBP) cleavage requires Cdc48 and Dsc5, a ubiquitin regulatory X domain-containing subunit of the Golgi Dsc E3 ligase.

    Science.gov (United States)

    Stewart, Emerson V; Lloyd, S Julie-Ann; Burg, John S; Nwosu, Christine C; Lintner, Robert E; Daza, Riza; Russ, Carsten; Ponchner, Karen; Nusbaum, Chad; Espenshade, Peter J

    2012-01-01

    Schizosaccharomyces pombe Sre1 is a membrane-bound transcription factor that controls adaptation to hypoxia. Like its mammalian homolog, sterol regulatory element-binding protein (SREBP), Sre1 activation requires release from the membrane. However, in fission yeast, this release occurs through a strikingly different mechanism that requires the Golgi Dsc E3 ubiquitin ligase complex and the proteasome. The mechanistic details of Sre1 cleavage, including the link between the Dsc E3 ligase complex and proteasome, are not well understood. Here, we present results of a genetic selection designed to identify additional components required for Sre1 cleavage. From the selection, we identified two new components of the fission yeast SREBP pathway: Dsc5 and Cdc48. The AAA (ATPase associated with diverse cellular activities) ATPase Cdc48 and Dsc5, a ubiquitin regulatory X domain-containing protein, interact with known Dsc complex components and are required for SREBP cleavage. These findings provide a mechanistic link between the Dsc E3 ligase complex and the proteasome in SREBP cleavage and add to a growing list of similarities between the Dsc E3 ligase and membrane E3 ligases involved in endoplasmic reticulum-associated degradation.

  3. Subunit architecture of the Golgi Dsc E3 ligase required for sterol regulatory element-binding protein (SREBP) cleavage in fission yeast.

    Science.gov (United States)

    Lloyd, S Julie-Ann; Raychaudhuri, Sumana; Espenshade, Peter J

    2013-07-19

    The membrane-bound sterol regulatory element-binding protein (SREBP) transcription factors regulate lipogenesis in mammalian cells and are activated through sequential cleavage by the Golgi-localized Site-1 and Site-2 proteases. The mechanism of fission yeast SREBP cleavage is less well defined and, in contrast, requires the Golgi-localized Dsc E3 ligase complex. The Dsc E3 ligase consists of five integral membrane subunits, Dsc1 through Dsc5, and resembles membrane E3 ligases that function in endoplasmic reticulum-associated degradation. Using immunoprecipitation assays and blue native electrophoresis, we determined the subunit architecture for the complex of Dsc1 through Dsc5, showing that the Dsc proteins form subcomplexes and display defined connectivity. Dsc2 is a rhomboid pseudoprotease family member homologous to mammalian UBAC2 and a central component of the Dsc E3 ligase. We identified conservation in the architecture of the Dsc E3 ligase and the multisubunit E3 ligase gp78 in mammals. Specifically, Dsc1-Dsc2-Dsc5 forms a complex resembling gp78-UBAC2-UBXD8. Further characterization of Dsc2 revealed that its C-terminal UBA domain can bind to ubiquitin chains but that the Dsc2 UBA domain is not essential for yeast SREBP cleavage. Based on the ability of rhomboid superfamily members to bind transmembrane proteins, we speculate that Dsc2 functions in SREBP recognition and binding. Homologs of Dsc1 through Dsc4 are required for SREBP cleavage and virulence in the human opportunistic pathogen Aspergillus fumigatus. Thus, these studies advance our organizational understanding of multisubunit E3 ligases involved in endoplasmic reticulum-associated degradation and fungal pathogenesis.

  4. Fragment-Based Screening for Enzyme Inhibitors Using Calorimetry.

    Science.gov (United States)

    Recht, Michael I; Nienaber, Vicki; Torres, Francisco E

    2016-01-01

    Isothermal titration calorimetry (ITC) provides a sensitive and accurate means by which to study the thermodynamics of binding reactions. In addition, it enables label-free measurement of enzymatic reactions. The advent of extremely sensitive microcalorimeters have made it increasingly valuable as a tool for hit validation and characterization, but its use in primary screening is hampered by requiring large quantities of reagents and long measurement times. Nanocalorimeters can overcome these limitations of conventional ITC, particularly for screening libraries of 500-1000 compounds such as those encountered in fragment-based lead discovery. This chapter describes how nanocalorimetry and conventional microcalorimetry can be used to screen compound libraries for enzyme inhibitors.

  5. Shashlik calorimetry a combined Shashlik + Preshower detector for LHC

    CERN Document Server

    Badier, J; Busata, A; CERN. Geneva. Detector Research and Development Committee

    1993-01-01

    Shashlik Calorimetry is a new technique which has been developed to read out the light from lead/scintillator sampling calorimeters, using wavelength shifters and optical fibres. The light yield is in excess of 10000 photons per GeV with fine lateral segmentation and minimum dead space. It is expected that such calorimeters can be buildt at relatively low cost. The first results on energy resolution and angular resolution, obtained in a non-projective prototype exposed to high energy electrons, are encouraging. Further research and development are essential before building a full scale projective detector.

  6. 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.

  7. 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.

  8. 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...

  9. Analysis of the retrogradation of low starch concentration gels using differential scanning calorimetry, rheology, and nuclear magnetic resonance spectroscopy.

    Science.gov (United States)

    Lewen, Kenneth S; Paeschke, Teri; Reid, Joshua; Molitor, Paul; Schmidt, Shelly J

    2003-04-09

    The retrogradation of 5, 10, 15, and 25% corn starch gels was measured using differential scanning calorimetry (DSC), rheology, and an array of NMR spectroscopy techniques. During the initial (retrogradation, an increase in G' corresponding to an increase in the number of solid protons participating in cross-relaxation (M(B)(0) was observed for all four concentrations studied. During the latter (>24 h) stage of retrogradation, amylopectin recrystallization becomes the dominant process as measured by an increase in deltaH(r) for the 25% starch gel, which corresponded to a further increase in. A decrease in the molecular mobility of the liquid component was observed by decreases in (17)O T(2), (1)H D(0), and T(2A). The value for T(2B) (the solid transverse relaxation time) did not change with concentration or time indicating that the mobility of the solid component does not change over time despite the conversion of the highly mobile starch fraction to the less mobile solid state during retrogradation.

  10. Influence of rare earth elements on solidification behavior of a high speed steel for roll using differential scanning calorimetry

    Institute of Scientific and Technical Information of China (English)

    WANG Mingjia; CHEN Lei; WANG Zixi; BAO Er

    2011-01-01

    The influence of rare earths (RE) on solidification behavior of a high speed steel for roll was investigated by using differential scanning calorimetry (DSC) in combination of microstructure analysis.It was found that the sequence of solidification was L→γ,L→γ+MC,L→γ+M2C,L→γ+M6C,respectively.The start temperature and the latent heat liberated by unit mass of L→γ and L→γ+MC increased with increase of RE addition,indicating that RE could trigger the crystallization of the primary γ and the MC carbide more effectively.The promoting effect of RE on the heterogeneous nucleation was believed to be an important cause of this effect.Grain refinement,discontinuous network of eutectic carbides and disperse and finer MC were observed in the samples with RE addition,moreover,RES could act as the heterogeneous nucleus of the MC.RE addition was favorable for stable M6C at the expense of the metastable M2C.

  11. 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.

  12. Thermophysical analysis of II-VI semiconductors by PPE calorimetry and lock-in thermography

    Energy Technology Data Exchange (ETDEWEB)

    Streza, M.; Dadarlat, D. [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath, 400293 Cluj-Napoca (Romania); Strzałkowski, K. [Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 (Poland)

    2013-11-13

    An accurate determination of thermophysical properties such as thermal diffusivity, thermal effusivity and thermal conductivity is extremely important for characterization and quality assurance of semiconductors. Thermal diffusivity and effusivity of some binary semiconductors have been investigated. Two experimental techniques were used: a contact technique (PPE calorimetry) and a non contact technique (lock-in thermography). When working with PPE, in the back (BPPE) configuration and in the thermally thick regim of the pyroelectric sensor, we can get the thermal diffusivity of the sample by performing a scanning of the excitation frequency of radiation. Thermal effusivity is obtained in front configuration (sensor directly irradiated and sample in back position) by performing a thickness scan of a coupling fluid. By using the lock-in thermography technique, the thermal diffusivity of the sample is obtained from the phase image. The results obtained by the two techniques are in good agreement. Nevertheless, for the determination of thermal diffusivity, lock-in thermography is preferred.

  13. A unified framework based on the binding polynomial for characterizing biological systems by isothermal titration calorimetry.

    Science.gov (United States)

    Vega, Sonia; Abian, Olga; Velazquez-Campoy, Adrian

    2015-04-01

    Isothermal titration calorimetry (ITC) has become the gold-standard technique for studying binding processes due to its high precision and sensitivity, as well as its capability for the simultaneous determination of the association equilibrium constant, the binding enthalpy and the binding stoichiometry. The current widespread use of ITC for biological systems has been facilitated by technical advances and the availability of commercial calorimeters. However, the complexity of data analysis for non-standard models is one of the most significant drawbacks in ITC. Many models for studying macromolecular interactions can be found in the literature, but it looks like each biological system requires specific modeling and data analysis approaches. The aim of this article is to solve this lack of unity and provide a unified methodological framework for studying binding interactions by ITC that can be applied to any experimental system. The apparent complexity of this methodology, based on the binding polynomial, is overcome by its easy generalization to complex systems.

  14. 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.

  15. Crystallization behavior of biodiesel based on differential scanning calorimetry and thermodynamic model%基于差示扫描量热法和热力学模型的生物柴油结晶行为分析

    Institute of Scientific and Technical Information of China (English)

    梅德清; 谭文兵; 张永涛; 袁银男

    2014-01-01

    棕榈酸甲酯(C16:0)、硬脂酸甲酯(C18:0)和油酸甲酯(C18:1)是生物柴油的主要组成部分。为了深入探究生物柴油的结晶行为,该文基于差示扫描量热法(differential scanning calorimetry, DSC)分析了这3种脂肪酸酯的物性参数,研究发现饱和脂肪酸甲酯 C16:0和 C18:0的熔点和熔化焓远远高出不饱和脂肪酸甲酯 C18:1的值,C16:0和C18:0的熔点分别为301.57、310.92 K,C18:1的熔点为255.01 K。对脂肪酸酯组成的二元溶液进行DSC扫描, DSC曲线出现了2个放热峰,并且溶液的结晶点要低于首先析出的饱和脂肪酸酯纯物质时的熔点;随着饱和脂肪酸酯质量分数的增加溶液的结晶点温度也相应提高。将生物柴油当作由多元脂肪酸甲酯的混合溶液时,C16:0和C18:0等饱和脂肪酸甲酯作为溶质,C18:1等不饱和脂肪酸甲酯作为溶剂,建立了热力学模型计算溶液的结晶点温度。将脂肪酸甲酯的混合溶液近似为理想溶液时对此模型进一步简化,并利用简化模型计算得到4种生物柴油的结晶温度,与实测值进行比较得到了很好的验证效果。该研究可为优化生物柴油低温流动性的技术措施提供参考。%Biodiesel, as a renewable alternative fuel, is easily crystallized at low temperature, which limits the application of engines fueled with biodiesel. Biodiesel is mainly composed of methyl palmitate (C16:0), methyl stearate (C18:0) and methyl oleate (C18:1). The properties of fuel are closely related to the properties of its compositions, and the fuel properties will change with different mole fraction ratios of some composition. So, it is very important to research the thermal parameters of different compositions. Differential scanning calorimetry (DSC) is a thermo analytical technique by which the difference in the amount of heat required to increase the temperature of a sample and reference is measured as a

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

    Science.gov (United States)

    Fernández, José M; Plaza, César; Polo, Alfredo; Plante, Alain F

    2012-01-01

    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 CO(2) respired indicated that the organic matter in the TS was the least stable, while that in the CS was the most stable. This was confirmed by changes detected with the spectroscopic methods in the composition of the organic wastes due to C mineralization. Differences were especially pronounced for TS, which showed a remarkable loss of aliphatic and proteinaceous compounds during the incubation process. TG, and especially DSC analysis, clearly reflected these differences between the three organic wastes before and after the incubation. Furthermore, the calculated energy density, which represents the energy available per unit of organic

  17. Entalpia reticular, entalpia de fusão e temperatura de fusão de adutos: algumas correlações empíricas utilizando DSC

    OpenAIRE

    Farias Robson Fernandes de

    1999-01-01

    By using DSC data is shown that there are empirical correlations between lattice enthalpy, melting enthalpy and the temperature of melting for adducts, and that is possible, using only a single DSC curve, estimate the value of DM Hmq.

  18. Advanced ion beam calorimetry for the test facility ELISE

    Science.gov (United States)

    Nocentini, R.; Bonomo, F.; Pimazzoni, A.; Fantz, U.; Franzen, P.; Fröschle, M.; Heinemann, B.; Pasqualotto, R.; Riedl, R.; Ruf, B.; Wünderlich, D.

    2015-04-01

    The negative ion source test facility ELISE (Extraction from a Large Ion Source Experiment) is in operation since beginning of 2013 at the Max-Planck-Institut für Plasmaphysik (IPP) in Garching bei München. The large radio frequency driven ion source of ELISE is about 1×1 m2 in size (1/2 the ITER source) and can produce a plasma for up to 1 h. Negative ions can be extracted and accelerated by an ITER-like extraction system made of 3 grids with an area of 0.1 m2, for 10 s every 3 minutes. A total accelerating voltage of up to 60 kV is available, i.e. a maximum ion beam power of about 1.2 MW can be produced. ELISE is equipped with several beam diagnostic tools for the evaluation of the beam characteristics. In order to evaluate the beam properties with a high level of detail, a sophisticated diagnostic calorimeter has been installed in the test facility at the end of 2013, starting operation in January 2014. The diagnostic calorimeter is split into 4 copper plates with separate water calorimetry for each of the plates. Each calorimeter plate is made of 15×15 copper blocks, which act as many separate inertial calorimeters and are attached to a copper plate with an embedded cooling circuit. The block geometry and the connection with the cooling plate are optimized to accurately measure the time-averaged power of the 10 s ion beam. The surface of the blocks is covered with a black coating that allows infrared (IR) thermography which provides a 2D profile of the beam power density. In order to calibrate the IR thermography, 48 thermocouples are installed in as many blocks, arranged in two vertical and two horizontal rows. The paper describes the beam calorimetry in ELISE, including the methods used for the IR thermography, the water calorimetry and the analytical methods for beam profile evaluation. It is shown how the maximum beam inhomogeneity amounts to 13% in average. The beam divergence derived by IR thermography ranges between 1° and 4° and correlates

  19. 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 ...

  20. 轻薄易用动你心——索尼DSC-T5

    Institute of Scientific and Technical Information of China (English)

    赵欣

    2005-01-01

    作为拥有目前世界轻薄机身记录的DSC—T7的下一代机型,DSC—T5并不刻意再在“薄”字上做文章,却走一条更时尚.更易用的道路。从名字上也可以看出.DSC-T5并没有要超越DSC—T7的意思.DSC—T5将以更适合大众使用的形象出现。

  1. 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.

  2. 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

  3. 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...... 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....

  4. Hydroxylamine nitrate self-catalytic kinetics study with adiabatic calorimetry.

    Science.gov (United States)

    Liu, Lijun; Wei, Chunyang; Guo, Yuyan; Rogers, William J; Sam Mannan, M

    2009-03-15

    Hydroxylamine nitrate (HAN) is an important member of the hydroxylamine compound family with applications that include equipment decontamination in the nuclear industry and aqueous or solid propellants. Due to its instability and autocatalytic behavior, HAN has been involved in several incidents at the Hanford and Savannah River Site (SRS) [Technical Report on Hydroxylamine Nitrate, US Department of Energy, 1998]. Much research has been conducted on HAN in different areas, such as combustion mechanism, decomposition mechanism, and runaway behavior. However, the autocatalytic decomposition behavior of HAN at runaway stage has not been fully addressed due to its highly exothermic and rapid decomposition behavior. This work is focused on extracting HAN autocatalytic kinetics and analyzing HAN critical behavior from adiabatic calorimetry measurements. A lumped autocatalytic kinetic model for HAN and associated model parameters are determined. Also the storage and handling critical conditions of diluted HAN solution without metal presence are quantified.

  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...... gradients equilibrium cannot be obtained with the sample size used (1 g liquid). Correcting for non-equilibrium between reference block and sample, the Gibbs-Thomson equation seems applicable for estimation of pore sizes of the investigated size. The estimate may be further improved by taking the effect...... to limit transport of liquid, whereas heating should be undertaken at a low rate to limit the effect of non-equilibrium....

  6. DETECTION OF Tg BY MODULATED DIFFERENTIAL SCANNING CALORIMETRY

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    The glassy transition of the polyethylene terephthalate (PET) samples which have been subjected to solvent induced crystallization (SINC) was investigated by modulated differential scanning calorimetry (MDSC) and density measurement. The differential of heat capacity signal, d Cp/dT from MDSC, was used to monitor the SINC process. It reveals that the Tg temperature shifts to higher value with the advancement of SINC. When the toluene-immersing time was longer (168h), the detection of Tg become more difficult, because some smaller peaks emerged at the lower temperatures and these are explained as the movement of small segments in the amorphous region. These observed results are due to the morphology and structure introduced by the SINC process.

  7. Isothermal titration calorimetry of ion-coupled membrane transporters.

    Science.gov (United States)

    Boudker, Olga; Oh, SeCheol

    2015-04-01

    Binding of ligands, ranging from proteins to ions, to membrane proteins is associated with absorption or release of heat that can be detected by isothermal titration calorimetry (ITC). Such measurements not only provide binding affinities but also afford direct access to thermodynamic parameters of binding--enthalpy, entropy and heat capacity. These parameters can be interpreted in a structural context, allow discrimination between different binding mechanisms and guide drug design. In this review, we introduce advantages and limitations of ITC as a methodology to study molecular interactions of membrane proteins. We further describe case studies where ITC was used to analyze thermodynamic linkage between ions and substrates in ion-coupled transporters. Similar type of linkage analysis will likely be applicable to a wide range of transporters, channels, and receptors.

  8. Isothermal titration calorimetry of membrane proteins - progress and challenges.

    Science.gov (United States)

    Rajarathnam, Krishna; Rösgen, Jörg

    2014-01-01

    Integral membrane proteins, including G protein-coupled receptors (GPCR) and ion channels, mediate diverse biological functions that are crucial to all aspects of life. The knowledge of the molecular mechanisms, and in particular, the thermodynamic basis of the binding interactions of the extracellular ligands and intracellular effector proteins is essential to understand the workings of these remarkable nanomachines. In this review, we describe how isothermal titration calorimetry (ITC) can be effectively used to gain valuable insights into the thermodynamic signatures (enthalpy, entropy, affinity, and stoichiometry), which would be most useful for drug discovery studies, considering that more than 30% of the current drugs target membrane proteins. This article is part of a Special Issue entitled: Structural and biophysical characterisation of membrane protein-ligand binding.

  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. 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.

  11. Applications of isothermal titration calorimetry in protein science.

    Science.gov (United States)

    Liang, Yi

    2008-07-01

    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.

  12. 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: $_{E}/E ≈ 0.265/\\sqrt{E(GeV)} + 1.2 times 10^{-4} E(GeV)$.

  13. Efficient Isothermal Titration Calorimetry Technique Identifies Direct Interaction of Small Molecule Inhibitors with the Target Protein.

    Science.gov (United States)

    Gal, Maayan; Bloch, Itai; Shechter, Nelia; Romanenko, Olga; Shir, Ofer M

    2016-01-01

    Protein-protein interactions (PPI) play a critical role in regulating many cellular processes. Finding novel PPI inhibitors that interfere with specific binding of two proteins is considered a great challenge, mainly due to the complexity involved in characterizing multi-molecular systems and limited understanding of the physical principles governing PPIs. Here we show that the combination of virtual screening techniques, which are capable of filtering a large library of potential small molecule inhibitors, and a unique secondary screening by isothermal titration calorimetry, a label-free method capable of observing direct interactions, is an efficient tool for finding such an inhibitor. In this study we applied this strategy in a search for a small molecule capable of interfering with the interaction of the tumor-suppressor p53 and the E3-ligase MDM2. We virtually screened a library of 15 million small molecules that were filtered to a final set of 80 virtual hits. Our in vitro experimental assay, designed to validate the activity of mixtures of compounds by isothermal titration calorimetry, was used to identify an active molecule against MDM2. At the end of the process the small molecule (4S,7R)-4-(4-chlorophenyl)-5-hydroxy-2,7-dimethyl-N-(6-methylpyridin-2-yl)-4,6,7,8 tetrahydrIoquinoline-3-carboxamide was found to bind MDM2 with a dissociation constant of ~2 µM. Following the identification of this single bioactive compound, spectroscopic measurements were used to further characterize the interaction of the small molecule with the target protein. 2D NMR spectroscopy was used to map the binding region of the small molecule, and fluorescence polarization measurement confirmed that it indeed competes with p53.

  14. Interaction of local and general anaesthetics with liposomal membrane models: a QCM-D and DSC study.

    Science.gov (United States)

    Paiva, José Gabriel; Paradiso, Patrizia; Serro, Ana Paula; Fernandes, Anabela; Saramago, Benilde

    2012-06-15

    The behaviour of four local anaesthetics (lidocaine, levobupivacaine, ropivacaine and tetracaine) and one general anaesthetic (propofol) is compared when interacting with two types of model membranes: supported layers of liposomes and liposomes in solution. Several liposomal compositions were tested: dimyristoylphosphatidylcholine (DMPC), binary mixtures of DMPC with cholesterol (CHOL), and ternary mixtures of dipalmitoylphosphatidylcholine (DPPC), DMPC, and CHOL. A quartz crystal microbalance with dissipation, QCM-D, was used to assess changes in the properties of supported layers of liposomes. The effect of the anaesthetics on the phase behaviour of the liposomes in suspension was determined by differential scanning calorimetry. Both techniques show that all anaesthetics have a fluidizing effect on the model membranes but, apparently, the solid supported liposomes are less affected by the anaesthetics than the liposomes in solution. Although the different anaesthetics were compared at different concentrations, tetracaine and propofol seem to induce the strongest perturbation on the liposome membrane. The resistance of the liposomes to the anaesthetic action was found to increase with the presence of cholesterol, while adding DPPC to the binary mixture DMPC+CHOL does not change its behaviour. The novelty of the present work resides upon three points: (1) the use of supported layers of liposomes as model membranes to study interactions with anaesthetics; (2) application of QCM-D to assess changes of the adsorbed liposomes; (3) a comparison of the effect of local and general anaesthetics interacting with various model membranes in similar experimental conditions.

  15. Decentralized Adaptive Neural Output-Feedback DSC for Switched Large-Scale Nonlinear Systems.

    Science.gov (United States)

    Long, Lijun; Zhao, Jun

    2016-03-08

    In this paper, for a class of switched large-scale uncertain nonlinear systems with unknown control coefficients and unmeasurable states, a switched-dynamic-surface-based decentralized adaptive neural output-feedback control approach is developed. The approach proposed extends the classical dynamic surface control (DSC) technique for nonswitched version to switched version by designing switched first-order filters, which overcomes the problem of multiple ``explosion of complexity.'' Also, a dual common coordinates transformation of all subsystems is exploited to avoid individual coordinate transformations for subsystems that are required when applying the backstepping recursive design scheme. Nussbaum-type functions are utilized to handle the unknown control coefficients, and a switched neural network observer is constructed to estimate the unmeasurable states. Combining with the average dwell time method and backstepping and the DSC technique, decentralized adaptive neural controllers of subsystems are explicitly designed. It is proved that the approach provided can guarantee the semiglobal uniformly ultimately boundedness for all the signals in the closed-loop system under a class of switching signals with average dwell time, and the tracking errors to a small neighborhood of the origin. A two inverted pendulums system is provided to demonstrate the effectiveness of the method proposed.

  16. Thermal stability of the DSC ruthenium dye C106 in robust electrolytes

    DEFF Research Database (Denmark)

    Lund, Torben; Phuong, Nguyen Tuyet; Pechy, Peter

    2014-01-01

    the dye from the TiO2 particles and analyzed its by HPLC coupled to UV/Vis and electro spray mass spectrometry. Samples prepared in the glove box gave the highest stability with a steady state photo anode surface concentration of 80% C106 intact and the remaining ∼20% being the N-butylbenzimidazole (NBB......We have investigated the thermal stability of the heteroleptic ruthenium complex C106 employed as a sensitizer in dye-sensitized solar cells. The C106 was adsorbed on TiO2 particles and exposed to 2 different iodide/triidode based redox electrolytes A and B at 80 °C for up to 1500 h in sealed glass...... of the degree of dye loading of the TiO2 particles and the ratio between the amount of dyed TiO2 particles and electrolyte volume. Assuming that this substitution is the predominant loss mechanism in a DSC during thermal stress, we estimate the reduction in the DSC efficiency after long term heat to be 12...

  17. Interaction of formin FH2 with skeletal muscle actin. EPR and DSC studies.

    Science.gov (United States)

    Kupi, Tünde; Gróf, Pál; Nyitrai, Miklós; Belágyi, József

    2013-10-01

    Formins are highly conserved proteins that are essential in the formation and regulation of the actin cytoskeleton. The formin homology 2 (FH2) domain is responsible for actin binding and acts as an important nucleating factor in eukaryotic cells. In this work EPR and DSC were used to investigate the properties of the mDia1-FH2 formin fragment and its interaction with actin. MDia1-FH2 was labeled with a maleimide spin probe (MSL). EPR results suggested that the MSL was attached to a single SH group in the FH2. In DSC and temperature-dependent EPR experiments we observed that mDia1-FH2 has a flexible structure and observed a major temperature-induced conformational change at 41 °C. The results also confirmed the previous observation obtained by fluorescence methods that formin binding can destabilize the structure of actin filaments. In the EPR experiments the intermolecular connection between the monomers of formin dimers proved to be flexible. Considering the complex molecular mechanisms underlying the cellular roles of formins this internal flexibility of the dimers is probably important for manifestation of their biological functions.

  18. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    De La Taille, Ch.

    2009-09-15

    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

  20. An evaluation of the use of calorimetry for shipper-receiver measurements of plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Rodenburg, W.W.

    1977-12-01

    The purpose of this report is to evaluate the relative merit of using calorimetry for shipper-receiver (S-R) exchanges of Pu. In particular, this evaluation concentrates on the accountability and the diversion detection aspects of calorimetry. Three different modes of use were considered: (1) calorimetry alone, that is S-R exchanges based on power (wattage) measurements; (2) calorimetry plus chemical assay, similar to the present weight plus chemical assay system, and (3) calorimetry plus gamma-ray spectrometry, a totally nondestructive Pu assay method. The relative merit of ball three applications was judged using the present methods as a base case. Some of the factors considered were random and systematic errors, timeliness, costs (both operating and capital) and reliability.

  1. Advances in the analysis of isothermal titration calorimetry data for ligand-DNA interactions.

    Science.gov (United States)

    Buurma, Niklaas J; Haq, Ihtshamul

    2007-06-01

    Isothermal titration calorimetry (ITC) is a well established technique for the study of biological interactions. The strength of ITC is that it directly measures enthalpy changes associated with interactions. Experiments can also yield binding isotherms allowing quantification of equilibrium binding constants, hence an almost complete thermodynamic profile can be established. Principles and application of ITC have been well documented over recent years, experimentally the technique is simple to use and in ideal scenarios data analysis is trivial. However, ITC experiments can be designed such that previously inaccessible parameters can be evaluated. We outline some of these advances, including (1) exploiting different experimental conditions; (2) low affinity systems; (3) high affinity systems and displacement assays. In addition we ask the question: What if data cannot be fit using the fitting functions incorporated in the data-analysis software that came with your ITC? Examples where such data might be generated include systems following non 1:n binding patterns and systems where binding is coupled to other events such as ligand dissociation. Models dealing with such data are now appearing in literature and we summarise examples relevant for the study of ligand-DNA interactions.

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

    CERN Document Server

    LiuKun; Zhu Mei Hong; Wei Bin; Liu Bang Chang; Zhang Xia; Gao Long Ma; Zhang Guo Yong; He Wen Jun; Gao Bao Xin

    2002-01-01

    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 sup - sup 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.

  3. 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.

  4. Comparison of dual-echo DSC-MRI- and DCE-MRI-derived contrast agent kinetic parameters.

    Science.gov (United States)

    Quarles, C Chad; Gore, John C; Xu, Lei; Yankeelov, Thomas E

    2012-09-01

    The application of dynamic susceptibility contrast (DSC) MRI methods to assess brain tumors is often confounded by the extravasation of contrast agent (CA). Disruption of the blood-brain barrier allows CA to leak out of the vasculature leading to additional T(1), T(2) and T(2) relaxation effects in the extravascular space, thereby affecting the signal intensity time course in a complex manner. The goal of this study was to validate a dual-echo DSC-MRI approach that separates and quantifies the T(1) and T(2) contributions to the acquired signal and enables the estimation of the volume transfer constant, K(trans), and the volume fraction of the extravascular extracellular space, v(e). To test the validity of this approach, DSC-MRI- and dynamic contrast enhanced (DCE) MRI-derived K(trans) and v(e) estimates were spatially compared in both 9L and C6 rat brain tumor models. A high degree of correlation (concordance correlation coefficients >0.83, Pearson's r>0.84) and agreement was found between the DSC-MRI- and DCE-MRI-derived measurements. These results indicate that dual-echo DSC-MRI can be used to simultaneously extract reliable DCE-MRI kinetic parameters in brain tumors in addition to conventional blood volume and blood flow metrics.

  5. 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.

  6. 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.

  7. 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.

  8. The Electromagnetic Calorimetry of the PANDA Detector at FAIR

    Science.gov (United States)

    Novotny, R. W.; PANDA Collaboration

    2012-12-01

    The PANDA collaboration at FAIR, Germany, will focus on undiscovered charm-meson states and glueballs in antiproton annihilations to study QCD phenomena in the non-perturbative regime. For fixed target experiments at the storage ring HESR a 4π-detector for tracking, particle ID and calorimetry is under development and construction to operate at high annihilation rates up to 20 MHz. The electromagnetic calorimeters are composed of a target spectrometer (EMC) based on PbWO4 crystals and a shashlyk-type sampling calorimeter at the most forward region. The EMC, comprising more than 15,000 crystals, is operated at a temperature of -25°C and read-out via large-area avalanche photo-diodes or vacuum phototriodes/tetrodes. The photo sensor signals are continuously digitized by sampling ADCs. More than 50% of the high quality PWO-II crystals are delivered and tested. The excellent performance with respect to energy, time and position information was determined over a shower energy range from 10 MeV up to 15 GeV by operating several prototype detectors. In addition, the concept of stimulated recovery has been investigated to recover radiation damage on- and off-line during the calorimeter operation. Besides the overall concept of the target spectrometer the response function of the shashlyk spectrometer down to photon energies even below 100 MeV is presented.

  9. Survey of the year 2008: applications of isothermal titration calorimetry.

    Science.gov (United States)

    Falconer, Robert J; Penkova, Anita; Jelesarov, Ilian; Collins, Brett M

    2010-01-01

    Isothermal titration calorimetry (ITC) is a fast, accurate and label-free method for measuring the thermodynamics and binding affinities of molecular associations in solution. Because the method will measure any reaction that results in a heat change, it is applicable to many different fields of research from biomolecular science, to drug design and materials engineering, and can be used to measure binding events between essentially any type of biological or chemical ligand. ITC is the only method that can directly measure binding energetics including Gibbs free energy, enthalpy, entropy and heat capacity changes. Not only binding thermodynamics but also catalytic reactions, conformational rearrangements, changes in protonation and molecular dissociations can be readily quantified by performing only a small number of ITC experiments. In this review, we highlight some of the particularly interesting reports from 2008 employing ITC, with a particular focus on protein interactions with other proteins, nucleic acids, lipids and drugs. As is tradition in these reviews we have not attempted a comprehensive analysis of all 500 papers using ITC, but emphasize those reports that particularly captured our interest and that included more thorough discussions we consider exemplify the power of the technique and might serve to inspire other users.

  10. Measuring Multivalent Binding Interactions by Isothermal Titration Calorimetry.

    Science.gov (United States)

    Dam, Tarun K; Talaga, Melanie L; Fan, Ni; Brewer, Curtis F

    2016-01-01

    Multivalent glycoconjugate-protein interactions are central to many important biological processes. Isothermal titration calorimetry (ITC) can potentially reveal the molecular and thermodynamic basis of such interactions. However, calorimetric investigation of multivalency is challenging. Binding of multivalent glycoconjugates to proteins (lectins) often leads to a stoichiometry-dependent precipitation process due to noncovalent cross-linking between the reactants. Precipitation during ITC titration severely affects the quality of the baseline as well as the signals. Hence, the resulting thermodynamic data are not dependable. We have made some modifications to address this problem and successfully studied multivalent glycoconjugate binding to lectins. We have also modified the Hill plot equation to analyze high quality ITC raw data obtained from multivalent binding. As described in this chapter, ITC-driven thermodynamic parameters and Hill plot analysis of ITC raw data can provide valuable information about the molecular mechanism of multivalent lectin-glycoconjugate interactions. The methods described herein revealed (i) the importance of functional valence of multivalent glycoconjugates, (ii) that favorable entropic effects contribute to the enhanced affinities associated with multivalent binding, (iii) that with the progression of lectin binding, the microscopic affinities of the glycan epitopes of a multivalent glycoconjugate decrease (negative cooperativity), (iv) that lectin binding to multivalent glycoconjugates, especially to mucins, involves internal diffusion jumps, (bind and jump) and (v) that scaffolds of glycoconjugates influence their entropy of binding.

  11. Characterization of protein-protein interactions by isothermal titration calorimetry.

    Science.gov (United States)

    Velazquez-Campoy, Adrian; Leavitt, Stephanie A; Freire, Ernesto

    2015-01-01

    The analysis of protein-protein interactions has attracted the attention of many researchers from both a fundamental point of view and a practical point of view. From a fundamental point of view, the development of an understanding of the signaling events triggered by the interaction of two or more proteins provides key information to elucidate the functioning of many cell processes. From a practical point of view, understanding protein-protein interactions at a quantitative level provides the foundation for the development of antagonists or agonists of those interactions. Isothermal Titration Calorimetry (ITC) is the only technique with the capability of measuring not only binding affinity but the enthalpic and entropic components that define affinity. Over the years, isothermal titration calorimeters have evolved in sensitivity and accuracy. Today, TA Instruments and MicroCal market instruments with the performance required to evaluate protein-protein interactions. In this methods paper, we describe general procedures to analyze heterodimeric (porcine pancreatic trypsin binding to soybean trypsin inhibitor) and homodimeric (bovine pancreatic α-chymotrypsin) protein associations by ITC.

  12. Application of pressure perturbation calorimetry to lipid bilayers.

    Science.gov (United States)

    Heerklotz, Heiko; Seelig, Joachim

    2002-03-01

    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 changes of the pretransition and main transition of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), and the thermal expansivity of the fluid phase of DMPC and of two unsaturated lipids, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine and 1,2-dioleoyl-sn-glycero-3-phosphocholine. The high sensitivity of PPC instrumentation gives accurate data for alpha(V) and DeltaV even upon the application of relatively low pressures of approximately 5 bar.

  13. 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 (12.5 s in this case) to as large as 600 s 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.

  14. ANALYSIS OF BRANCHING DISTRIBUTION IN POLYETHYLENES BY DIFFERENTIAL SCANNING CALORIMETRY

    Institute of Scientific and Technical Information of China (English)

    Robert Shanks; Fei Chen; Gandara Amarasinghe

    2003-01-01

    Short chain branching has been characterized using thermal fractionation, a stepwise isothermal crystallization technique, followed by a melting analysis scan using differential scanning calorimetry. Short chain branching distribution was also characterized by a continuous slow cooling crystallization, followed by a melting analysis scan. Four different polyethylenes were studied: Ziegler-Natta gas phase, Ziegler-Natta solution, metallocene, constrained-geometry single site catalyzed polyethylenes. The branching distribution was calculated from a calibration of branch content with melting temperature. The lamellar thickness was calculated based on the thermodynamic melting temperature of each polyethylene and the surface free energy of the crystal face. The branching distribution and lamellar thickness distribution were used to calculate weight average branch content, mean lamellar thickness, and a branch dispersity index. The results for the branch content were in good agreement with the known comonomer content of the polyethylenes. A limitation was that high branch content polyethylenes did not reach their potential crystallization at ambient temperatures. Cooling to sub-ambient was necessary to equilibrate the crystallization, but melting temperature versus branch content was not applicable after cooling to below ambient because the calibration data were not performed in this way.

  15. ANALYSIS OF BRANCHING DISTRIBUTION IN POLYETHYLENES BY DIFFERENTIAL SCANNING CALORIMETRY

    Institute of Scientific and Technical Information of China (English)

    RobertShanks; FeiChan; GandaraAmarasinghe; RobertShanks

    2003-01-01

    Short chain branching has been characterized using thermal fractionation,a stepwise isothermal crystallization technique,followed by a melting analysis scan using differential scanning calorimetry.Short chain branching distribution was also characterized by a continuous slow cooling crystallization,followed by a melting analysis scan.Four different polyethylenes were studied:Ziegler-Natta gas phase,Ziegler-Natta solution,metallocene,constrained-geometry single site catalyzed polyethylenes.The branching distribution was calculated from a calibration of branch content with melting temperature.The lamellar thickness was calculated based on the thermodynamic melting temperature of each polyethylene and the surface free energy of the crystal face.The branching distribution and lamellar thickness distribution were used to calculate weight average branch content,mean lamellar thickness,and a branch dispersity index.The results for the branch content were in good agreement with the known comonomer content of the polyethylenes.A limitation was that high branch content polyethylenes did not reach their potential crystallization at ambient temperatures.Cooling to sub-ambient was necessary to equilibrate the crystallization,but melting temperature versus branch content was not applicable after cooling to below ambient because the calibration data were not performed in this way.

  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. Calorimetry study of microwave absorption of some solid materials.

    Science.gov (United States)

    He, Chun Lin; Ma, Shao Jian; Su, Xiu Juan; Chen, Yan Qing; Liang, Yu Shi

    2013-01-01

    In practice, the dielectric constant of a material varies the applied frequency the material composition, particle size, purity, temperature, physical state (solid or liquid), and moisture content. All of these parameters might change during processing, therefore, it is difficult to predict how well a material will absorb microwave energy in a given process. When the temperature is measured by a digital thermometer, it could not accurately reflect the true temperature of the bulk materials, especially for mixed materials. Thus, in this paper we measured the microwave absorption characteristics of different materials by calorimetry. The microwave power levels, irradiation times, and masses of the materials were varied. It was difficult to predict the microwave energy absorption characteristics of reagent-grade inorganic compounds based on their color, metallic cation, or water stoichiometry. CuO, MnO2, Fe3O4, and MnSO4 x H2O (Taishan) strongly absorbed microwave energy. Most of the remaining inorganic compounds were poor absorbers, with silica hardly absorbing any microwave energy. Carbon-based materials had significantly different microwave absorption characteristics. Activated carbon and coke were especially sensitive to microwaves, but different types of coal were poor absorbers. The jamesonite concentrate absorbed microwave energy strongly, while the zinc concentrate was a poor absorber.

  18. 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.

  19. 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.

  20. An evaluation of the transition temperature range of super-elastic orthodontic NiTi springs using differential scanning calorimetry.

    Science.gov (United States)

    Barwart, O; Rollinger, J M; Burger, A

    1999-10-01

    Differential scanning calorimetry (DSC) was used to determine the transition temperature ranges (TTR) of four types of super-elastic orthodontic nickel-titanium coil springs (Sentalloy). A knowledge of the TTR provides information on the temperature at which a NiTi wire or spring can assume superelastic properties and when this quality disappears. The spring types in this study can be distinguished from each other by their characteristic TTR during cooling and heating. For each tested spring type a characteristic TTR during heating (austenite transformation) and cooling (martensite transformation) was evaluated. The hysteresis of the transition temperature, found between cooling and heating, was 3.4-5.2 K. Depending on the spring type the austenite transformation started (As) at 9.7-17.1 degrees C and finished (Af) at 29.2-37 degrees C. The martensite transformation starting temperature (Ms) was evaluated at 32.6-25.4 degrees C, while Mf (martensite transformation finishing temperature) was 12.7-6.5 degrees C. The results show that the springs become super-elastic when the temperature increases and As is reached. They undergo a loss of super-elastic properties and a rapid decrease in force delivery when they are cooled to Mf. For the tested springs, Mf and As were found to be below room temperature. Thus, at room temperature and some degrees lower, all the tested springs exert super-elastic properties. For orthodontic treatment this means the maintenance of super-elastic behaviour, even when mouth temperature decreases to about room temperature as can occur, for example, during meals.

  1. PREFACE: XIV International Conference on Calorimetry in High Energy Physics

    Science.gov (United States)

    Wang, Yifang

    2011-03-01

    The International Conferences on Calorimetry in High Energy Physics (also known as the Calor Conference series, started in October 1990 at Fermilab) address all aspects of calorimetric particle detection and measurement, with an emphasis on high energy physics experiments. The XIV International Conference on Calorimetry in High Energy Physics (Calor 2010) was held at the campus of the Institute of High Energy Physics, Beijing, China, from May 10-14, 2010. This conference brought together more than 110 participants from 20 countries, including senior scientists and young physicists. During the five days of the conference, 98 presentations were given in seven plenary sessions. The attendees had in-depth discussions on the latest developments and innovations in calorimetry, including the exciting new LHC results. From the presentations, 83 papers were published in this proceedings. The success of the conference was due to the participants' enthusiasm and the excellent talks given by the speakers, and to the conveners for organizing the individual sessions. We would like to thank the International Advisory Committee for giving us the opportunity to host this Conference in Beijing. Finally we would like to thank all the people involved in the organization of the Conference, who have provided valuable local support. Yifang WangChair of Local Organizing Committee International Advisory Committee M DanilovITEP Moscow M DiemozINFN Roma I A EreditatoBern F L FabbriINFN Frascati T KobayashiICEPP Tokyo M LivanPavia University & INFN P LubranoINFN Perugia S MagillANL Argonne A MaioLIPP Lisbon H OberlackMPI Munich A ParaFermilab R WigmansTTU Lubbock R YoshidaANL Argonne R ZhuCaltech Local Organizing Committee Y WangIHEP (Chair) Y GaoTshinghua University T HuIHEP (Scientific secretary) C LiUSTC W LiIHEP J LuIHEP P WangIHEP T XuIHEP L ZhouIHEP Session Conveners 1) Materials and detectors - Junguang Lu (IHEP), Francesca Nessi (CERN) 2) Algorithm and simulation - Nural Akchurin

  2. Estimation of water-coal surface interaction during heat treatment of coal by use of FTir and DSC; FTir to DSC wo mochiita sekitan-mizu kan sogo sayo no teiryoteki hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Miura, K.; Mae, K.; Morozumi, F.; Kusakawa, T. [Kyoto University, Kyoto (Japan)

    1997-10-30

    The authors have recently presented a method to estimate the strength distribution of hydrogen bondings in coal using FTir and DSC. The method was applied to estimate the strength of coal-water interaction in two different coals and to estimate the enthalpy change deriving from the change in hydrogen bondings during the desorption of water. The estimated enthalpy change was compared with the total enthalpy change estimated by DSC measurement to examine the importance of hydrogen bondings during the desertion of water. 1 ref., 6 figs.

  3. DSC investigation of the effect of the new sigma ligand PPCC on DMPC lipid membrane.

    Science.gov (United States)

    Sarpietro, Maria Grazia; Accolla, Maria Lorena; Cova, Annamaria; Prezzavento, Orazio; Castelli, Francesco; Ronsisvalle, Simone

    2014-07-20

    The new sigma ligand cis-(±)-methyl (1R,2S/1S,2R)-2-[(4-hydroxy-4-phenylpiperidin-1-yl) methyl]-1-(4-methylphenyl) cyclopropanecarboxylate [(±)-PPCC] is a promising tool for the treatment of various diseases. With the aim to investigate the absorption of (±)-PPCC by the cell membranes, in this study we evaluated the influence on thermotropic behavior of membrane model exerted by PPCC both as free base or as oxalic salt. To fulfill this purpose differential scanning calorimetry was used. The findings highlight that PPCC affects the thermodynamic parameters of phospholipids in different manner depending on whether it is in the salt or base form as well as function of the amount of drugs dispersed in the lipid matrix. The salt form of PPCC was uptaken by the membrane model faster than the free base. In addition, preliminary information on the use of a lipophilic carrier for PPCC was obtained.

  4. Antiferroelectric liquid crystals studied by DSC, electro-optic, and dielectric methods

    Science.gov (United States)

    Marzec, M.; Fafara, A.; Wrobel, S.; Godlewska, Malgorzata; Dabrowski, Roman S.; Czuprynski, Krzysztof L.; Haase, Wolfgang

    2000-05-01

    Thermal properties of four liquid crystalline substances exhibiting antiferroelectric SmCA* and ferroelectric SmC* phases were studied using differential scanning calorimetry, texture observation, electrooptic measurements and dielectric spectroscopy. The measurements were performed both on heating and cooling of the samples. All four substances studied in this work are characterized by a complex polymorphism. The temperatures of phase transitions and enthalpy changes associated with them were determined. The transition from the liquid crystalline to the crystalline state showed significant hysteresis for all four substances studied. Textures observations and electrooptic measurements were performed using ITO cells having thickness from 6 to 10 micrometers . The measurements of spontaneous polarization were performed by means of reversal current method. Spontaneous polarization was measured for a few frequencies of the triangular voltage applied. Temperature dependencies of spontaneous polarization have been studied as a function of the side chain structure.

  5. Mechanisms of fibrinogen-acebutolol interactions: Insights from DSC, CD and LS.

    Science.gov (United States)

    Hassan, Natalia; Ruso, Juan M; Somasundaran, P

    2011-02-01

    The complex formed due to the interaction of the amphiphilic betablocker acebutolol with fibrinogen in a buffer solution (50mN glycine, pH of 8.5) has been investigated using a multipronged physicochemical approach. Differential scanning calorimetry measurements of the complexes have shown no reversibility of thermal denaturation as indicated by the three observed peaks and the opposite role that acebutolol plays in the folding different domains of the fibrinogen molecule and the stability of such domains. While circular dichroism measurements have revealed that interaction of acebutolol with fibrinogen affects the protein secondary structure to a different extent depending on the temperature and drug concentration, dynamic light scattering analysis showed evidence for protein aggregation mainly to tetramers and dimers.

  6. 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.

  7. 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.

  8. Aplicação da calorimetria exploratória diferencial no estudo da cinética de transição alfa -> delta HMX Application of differential scanning calorimetry in the study of the kinetics of the alpha -> delta transition in HMX

    Directory of Open Access Journals (Sweden)

    Gilson da Silva

    2004-12-01

    Full Text Available Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX or octogen is a white crystalline substance which occurs in four polymorphous forms. It is used in a wide variety of military and industrial formulations owing to its suitable properties. Researchers have demonstrated the usefulness of this energetic material in explosive components. In the present work we apply differential scanning calorimetry (DSC to measure the a ® d solid-solid phase transition energy of HMX. The results obtained by Kissinger's and Ozawa's methods were 487 and 495 kJ/mol, respectively.

  9. Localization and interaction of hydroxyflavones with lipid bilayer model membranes: a study using DSC and multinuclear NMR.

    Science.gov (United States)

    Sinha, Ragini; Joshi, Akshada; Joshi, Urmila J; Srivastava, Sudha; Govil, Girjesh

    2014-06-10

    The localization and interaction of six naturally occurring flavones (FLV, 5HF, 6HF, 7HF, CHY and BLN) in DPPC bilayers were studied using DSC and multi-nuclear NMR. DSC results indicate that FLV and 6HF interact with alkyl chains. The (1)H NMR shows interaction of flavones with the sn-glycero region. Ring current induced chemical shifts indicate that 6HF and BLN acquire parallel orientation in bilayers. 2D NOESY spectra indicate partitioning of the B-ring into the alkyl chain region. The DSC, NMR and binding studies indicate that 5HF and 7HF are located near head group region, while 6HF, CHY and BLN are located in the vicinity of sn-glycero region, and FLV is inserted deepest in the membrane.

  10. Enthalpies of sublimation of ferrocene and nickelocene measured by calorimetry and the method of Langmuir

    Energy Technology Data Exchange (ETDEWEB)

    Rojas, Aaron, E-mail: arojas@cinvestav.mx [Departamento de Quimica del Centro de Investigacion y de Estudios Avanzados del IPN, Av. Instituto Politecnico Nacional 2508, C.P. 07360, Mexico D.F. (Mexico); Vieyra-Eusebio, Maria Teresa [Departamento de Quimica del Centro de Investigacion y de Estudios Avanzados del IPN, Av. Instituto Politecnico Nacional 2508, C.P. 07360, Mexico D.F. (Mexico)

    2011-11-15

    Highlights: > Calorimetric enthalpies of sublimation of ferrocene and nickelocene are supplied. > Sublimation enthalpies of both metallocenes were also obtained by indirect Langmuir's method. > Calorimetric and indirect enthalpies of sublimation are comparable in accuracy and dispersion. > Sublimation enthalpies are congruent with both compounds being monoclinic and isostructural. - Abstract: A quick and accurate methodology that is based on Langmuir's equation and that is developed by utilising a DSC7 device is proposed for the measurement of the enthalpies of sublimation of substances characterised by vapour pressures of approximately 1.0 Pa at room temperature. The procedure was applied to ferrocene and nickelocene; the accuracy and uncertainty associated with the experimental results show that the reliability of the developed indirect method is comparable to the direct calorimetric measurements also performed in this work. Furthermore, the melting data and crystal-phase heat capacities for both metallocenes were calorimetrically measured, whereas the gas-phase heat capacity for each metallic bis(cyclopentadienyl) was theoretically estimated by DFT calculations.

  11. The Thermal Conductivity Measurements of Solid Samples by Heat Flux Differantial Scanning Calorimetry

    Science.gov (United States)

    Kök, M.; Aydoǧdu, Y.

    2007-04-01

    The thermal conductivity of polyvinylchloride (PVC), polysytrene (PS) and polypropylene (PP) were measured by heat flux DSC. Our results are in good agreement with the results observed by different methods.

  12. 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.

  13. Continuous gradient temperature Raman spectroscopy and differential scanning calorimetry of N-3DPA and DHA from -100 to 10°C.

    Science.gov (United States)

    Broadhurst, C Leigh; Schmidt, Walter F; Nguyen, Julie K; Qin, Jianwei; Chao, Kuanglin; Aubuchon, Steven R; Kim, Moon S

    2017-03-22

    Docosahexaenoic acid (DHA, 22:6n-3) is exclusively utilized in fast signal processing tissues such as retinal, neural and cardiac. N-3 docosapentaenoic acid (n-3DPA, 22:5n-3), with just one less double bond, is also found in the marine food chain yet cannot substitute for DHA. Gradient temperature Raman spectroscopy (GTRS) applies the temperature gradients utilized in differential scanning calorimetry (DSC) to Raman spectroscopy, providing a straightforward technique to identify molecular rearrangements that occur near and at phase transitions. Herein we apply GTRS and both conventional and modulated DSC to n-3DPA and DHA from -100 to 20°C. Three-dimensional data arrays with 0.2°C increments and first derivatives allowed complete assignment of solid, liquid and transition state vibrational modes. Melting temperatures n-3DPA (-45°C) and DHA (-46°C) are similar and show evidence for solid-state phase transitions not seen in n-6DPA (-27°C melt). The C6H2 site is an elastic marker for temperature perturbation of all three lipids, each of which has a distinct three dimensional structure. N-3 DPA shows the spectroscopic signature of saturated fatty acids from C1 to C6. DHA does not have three aliphatic carbons in sequence; n-6DPA does but they occur at the methyl end, and do not yield the characteristic signal. DHA appears to have uniform twisting from C6H2 to C12H2 to C18H2 whereas n-6DPA bends from C12 to C18, centered at C15H2. For n-3DPA, twisting is centered at C6H2 adjacent to the C2-C3-C4-C5 aliphatic moiety. These molecular sites are the most elastic in the solid phase and during premelting.

  14. 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.)

  15. Assessing Coupled Protein Folding and Binding Through Temperature-Dependent Isothermal Titration Calorimetry.

    Science.gov (United States)

    Sahu, Debashish; Bastidas, Monique; Lawrence, Chad W; Noid, William G; Showalter, Scott A

    2016-01-01

    Broad interest in the thermodynamic driving forces of coupled macromolecular folding and binding is motivated by the prevalence of disorder-to-order transitions observed when intrinsically disordered proteins (IDPs) bind to their partners. Isothermal titration calorimetry (ITC) is one of the few methods available for completely evaluating the thermodynamic parameters describing a protein-ligand binding event. Significantly, when the effective ΔH° for the coupled folding and binding process is determined by ITC in a temperature series, the constant-pressure heat capacity change (ΔCp) associated with these coupled equilibria is experimentally accessible, offering a unique opportunity to investigate the driving forces behind them. Notably, each of these molecular-scale events is often accompanied by strongly temperature-dependent enthalpy changes, even over the narrow temperature range experimentally accessible for biomolecules, making single temperature determinations of ΔH° less informative than typically assumed. Here, we will document the procedures we have adopted in our laboratory for designing, executing, and globally analyzing temperature-dependent ITC studies of coupled folding and binding in IDP interactions. As a biologically significant example, our recent evaluation of temperature-dependent interactions between the disordered tail of FCP1 and the winged-helix domain from Rap74 will be presented. Emphasis will be placed on the use of publically available analysis programs written in MATLAB that facilitate quantification of the thermodynamic forces governing IDP interactions. Although motivated from the perspective of IDPs, the experimental design principles and data fitting procedures presented here are general to the study of most noncooperative ligand binding equilibria.

  16. 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.

  17. 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.

  18. Pressure perturbation calorimetry, heat capacity and the role of water in protein stability and interactions.

    Science.gov (United States)

    Cooper, A; Cameron, D; Jakus, J; Pettigrew, G W

    2007-12-01

    It is widely acknowledged, and usually self-evident, that solvent water plays a crucial role in the overall thermodynamics of protein stabilization and biomolecular interactions. Yet we lack experimental techniques that can probe unambiguously the nature of protein-water or ligand-water interactions and how they might change during protein folding or ligand binding. PPC (pressure perturbation calorimetry) is a relatively new technique based on detection of the heat effects arising from application of relatively small pressure perturbations (+/-5 atm; 1 atm=101.325 kPa) to dilute aqueous solutions of proteins or other biomolecules. We show here how this can be related to changes in solvation/hydration during protein-protein and protein-ligand interactions. Measurements of 'anomalous' heat capacity effects in a wide variety of biomolecular interactions can also be related to solvation effects as part of a quite fundamental principle that is emerging, showing how the apparently unusual thermodynamics of interactions in water can be rationalized as an inevitable consequence of processes involving the co-operative interaction of multiple weak interactions. This leads to a generic picture of the thermodynamics of protein folding stabilization in which hydrogen-bonding plays a much more prominent role than has been hitherto supposed.

  19. Enzyme activity determination on macromolecular substrates by isothermal titration calorimetry: application to mesophilic and psychrophilic chitinases.

    Science.gov (United States)

    Lonhienne, T; Baise, E; Feller, G; Bouriotis, V; Gerday, C

    2001-02-09

    Isothermal titration calorimetry has been applied to the determination of the kinetic parameters of chitinases (EC 3.2.1.14) by monitoring the heat released during the hydrolysis of chitin glycosidic bonds. Experiments were carried out using two different macromolecular substrates: a soluble polymer of N-acetylglucosamine and the insoluble chitin from crab shells. Different experimental temperatures were used in order to compare the thermodependence of the activity of two chitinases from the psychrophile Arthrobacter sp. TAD20 and of chitinase A from the mesophile Serratia marcescens. The method allowed to determine unequivocally the catalytic rate constant k(cat), the activation energy (E(a)) and the thermodynamic activation parameters (DeltaG(#), DeltaH(#), DeltaS(#)) of the chitinolytic reaction on the soluble substrate. The catalytic activity has also been determined on insoluble chitin, which displays an effect of substrate saturation by chitinases. On both substrates, the thermodependence of the activity of the psychrophilic chitinases was lower than that observed with the mesophilic counterpart.

  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. Single-crystal adsorption calorimetry and density functional theory of CO chemisorption on fcc Co{110}.

    Science.gov (United States)

    Liao, Kristine; Fiorin, Vittorio; Gunn, David S D; Jenkins, Stephen J; King, David A

    2013-03-21

    Using single-crystal adsorption calorimetry (SCAC) and density functional theory (DFT), the interaction of carbon monoxide on fcc Co{110} is reported for the first time. The results indicate that adsorption is consistent with molecular chemisorption at all coverages. The initial heat of adsorption of 140 kJ mol(-1) is found in the range of heat values calorimetrically measured on other ferromagnetic metal surfaces, such as nickel and iron. DFT adsorption energies are in good agreement with the experimental results, and comparison between SCAC and DFT for CO on other ferromagnetic surfaces is made. The calculated dissociation barrier of 2.03 eV implies that dissociation at 300 K is unlikely even at the lowest coverage. At high coverages during the adsorption-desorption steady state regime, a pre-exponential factor for CO desorption of 1.2 × 10(17) s(-1) is found, implying a localised molecular adsorbed state prior to desorption in contrast to what we found with Ni surfaces. This result highlights the importance of the choice of the pre-exponential factor in evaluating the activation energy for desorption.

  2. Prospects for true calorimetry on Kerr black holes in core-collapse supernovae and mergers

    CERN Document Server

    van Putten, Maurice H P M; Tagoshi, Hideyuki; Tatsumi, Daisuke; Masa-Katsu, Fujimoto; Della Valle, Massimo

    2011-01-01

    Observational evidence for black hole spin down has been found in the normalized light curves of long GRBs in the BATSE catalogue. Over the duration $T_{90}$ of the burst, matter swept up by the central black hole is susceptible to non-axisymmetries producing gravitational radiation with a negative chirp. A time sliced matched filtering method is introduced to capture phase-coherence on intermediate timescales, $\\tau$, here tested by injection of templates into experimental strain noise, $h_n(t)$. For TAMA 300, $h_n(f)\\simeq 10^{-21}$ Hz$^{-\\frac{1}{2}}$ at $f=1$ kHz gives a sensitivity distance for a reasonably accurate extraction of the trajectory in the time frequency domain of about $D\\simeq 0.07-0.10$ Mpc for spin fown of black holes of mass $M=10-12M_\\odot$ with $\\tau=1$ s. Extrapolation to advanced detectors implies $D\\simeq 35-50$ Mpc for $h_n(f)\\simeq 2\\times 10^{-24}$ Hz$^{-\\frac{1}{2}}$ around 1 kHz, which will open a new window to rigorous calorimetry on Kerr black holes.

  3. Dual-Readout Calorimetry for High-Quality Energy Measurements

    CERN Document Server

    Gaudio, Gabriella

    2011-01-01

    In this report, we summarize new experimental results obtained in the past year, progress towards the construction of the new detector(s), as well as our near- and long-term plans. We also want to ask the SPSC to recognize this project as an integral part of the CERN experimental program by assigning an RD project number to it.

  4. Determination of Heats of Fusion: Using Differential Scanning Calorimetry for the AP Chemistry Courses.

    Science.gov (United States)

    Temme, Susan M.

    1995-01-01

    Describes an exercise designed to be used in an Advanced Placement (AP) chemistry course to accompany the study of thermodynamics. Uses Differential Scanning Calorimetry in teaching the concepts of thermochemistry and thermodynamics. (JRH)

  5. 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)

  6. 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''.

  7. A Shortened Norwegian Adaptation of the Lie Scale for Children (LSC) and the Defensiveness Scale for Children (DSC)

    Science.gov (United States)

    Haugen, Richard

    1978-01-01

    Ten items consisting of five DSC items and five LSC items were translated into Norwegian in order (a) to control the verbal anxiety responses from defensive tendencies, (b) to handle the problem of response set (the tendency to answer a questionnaire in a stereotyped way), and (c) to permit research concerning the nature of defensiveness itself.…

  8. 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.

  9. SIMULTANEOUS SAXS/WAXS/DSC STUDIES ON MICROSTRUCTURE OF CONVENTIONAL AND METALLOCENE-BASED ETHYLENE-BUTENE COPOLYMERS

    Institute of Scientific and Technical Information of China (English)

    Jun-ting Xu; Bo-tao Li; Zhi-qiang Fan; Anthony J. Ryan

    2004-01-01

    The fractions of one metallocene-based (mPE) and one conventional (znPE) ethylene-butene copolymer eluted at 80-82℃ from temperature rising elution fractionation were selected for DSC and time-resolved small angle X-ray scattering (SAXS) and wide angle X-ray scattering (WAXS) characterization. The DSC and WAXS results show that two crystal structures exist in both mPE and znPE: structure A with higher melting temperature and structure B with lower melting temperature. It was found that original znPE (s-znPE) contains more highly ordered structure A than original mPE (s-mPE)in spite of the higher comonomer content of znPE. Another structure C is also identified because of higher crystallinity measured by WAXS than by DSC and is attributed to the interfacial region. The SAXS data were analyzed with correlation function and two maxima were observed in s-mPE and s-znPE, in agreement with the conclusion of two crystal populations drawn from DSC and WAXS results. These two crystal populations have close long periods in s-mPE, but very different long periods in s-znPE. In contrast, freshly crystallized mPE and znPE (f-mPE and f-znPE) contain only a single crystal population with a broader distribution of long period.

  10. 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.

  11. 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...

  12. TG/DSC-FTIR and Py-GC investigation on pyrolysis characteristics of petrochemical wastewater sludge.

    Science.gov (United States)

    Chen, Jianbiao; Mu, Lin; Jiang, Bo; Yin, Hongchao; Song, Xigeng; Li, Aimin

    2015-09-01

    The pyrolysis characteristics of petrochemical wastewater sludge (PS) were evaluated using TG/DSC-FTIR and fixed-bed reactor with GC. TGA experiments indicated that the pyrolysis of PS proceeded in three phases, and the thermographs shifted to higher temperatures with increasing heating rate. Chars FTIR showed that the absorption of O-H, C-H, C=O and C-C decreased with pyrolysis temperatures increasing. Gases FTIR correspondingly showed that H2O, CO, and CH4 generated at higher temperatures. For the fixed-bed reactor tests, H2 and CO were relatively higher in the pyrolysis gases, and CH4 was negligible at 436K. The kinetic triplets of PS pyrolysis were estimated by Flynn-Wall-Ozawa, Kissinger-Akahira-Sunose, and integral master-plots method. The results suggested that the most potential kinetic models for the first and second phase were the order reaction model, while the random nucleation and nuclei growth model for the third phase.

  13. Sensory perception of the fermented goat milk: potential application of the DSC method

    Directory of Open Access Journals (Sweden)

    Martha Eunice de BESSA

    Full Text Available Abstract Goat milk and its derivatives present proven beneficial health properties; however, some sensory aspects associated to consumers’ expectations restrict the consumption growth for these products. In this work, fermented caprine milk formulations have been evaluated utilizing the methodology of Discourse of the Collective Subject (Discurso do Sujeito Coletivo – DSC associated to sensory analysis, in order to evaluate the perception of fermented caprine milk by consumers. The physicochemical and microbiological requisites of the fermented milk formulations evaluated during the storage, were according to current legislation. The probiotic characteristics of evaluated formulations were preserved, presenting viable cells counts for Lactobacillus acidophilus LA-5, Bifidobacterium BB-12, and Streptococcus thermophilus higher than 1x106 CFU/mL, along 28 days of storage. The Discourse of the Collective Subject results have shown that the typical taste and flavor, present in products derived from caprine milk, did not influence the purchase intention, which was expressive for all fermented milks. The Discourse of the Collective Subject has elucidated the consumers’ perspective, determining then both, the consumers’ profile and the factors interfering on the acquisition of fermented caprine milk.

  14. The terminal solid solubility of hydrogen in Zircaloy-4 and Opt-ZIRLO with a DSC

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae-hoon; Kim, Yong-soo [Hanyang Univ., Seoul (Korea, Republic of); Kim, Ju-seong [Korea Atomic Energy Institute, Daejeon (Korea, Republic of)

    2014-10-15

    Due to low neutron absorption cross section, good mechanical properties at high temperature and proper corrosion resistance; zirconium-based materials have been used commonly for nuclear core structural components. When the hydrogen content in cladding exceeds the terminal solid solubility (TSS) of hydrogen, the brittle hydrides can be precipitated. The brittle hydrides can threaten the integrity of cladding such as hydride re-orientation or DHC in dry storage conditions as well as in reactor operating conditions. In addition, it is known that the terminal solid solubility of hydrogen in zirconium alloys for dissolution (TSSD) and precipitation (TSSP) has a significant hysteresis. Thus, the TSS of hydrogen in zirconium alloys is an important factor and accurate knowledge of the TSS is required for evaluation of cladding integrity. In this study, the TSSD and TSSP for Zircaloy-4 and Opt-ZIRLO were measured. The TSS of hydrogen in Zry-4 and Opt-ZIRLO was investigated with a DSC in this study. The hydrogen concentrations in zirconium alloys ranged 40-741 wppm. Both TSSD and TSSP were similar to literature TSS results. However, Opt-ZIRLO had a higher terminal solid solubility of hydrogen than Zry-4 at the same temperature for less than about 400 wppm. The activation energy of Zircaloy-4 was relatively high compared with references, while the activation energy of Opt-ZIRLO was relatively low. It was considered that the chemical composition affects the TSS.

  15. 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

  16. Laser-Shock Experiments: Calorimetry Measurements to TPa Pressures

    Science.gov (United States)

    Jeanloz, R.

    2012-12-01

    Laser-driven shock experiments are more like calorimetry measurements, characterized by determinations of Hugoniot temperature (TH) as a function of shock velocity (US), rather than the equation-of-state measurements afforded by mechanical-impact experiments. This is because particle velocity (up) is often not accessible to direct measurement in laser-shock experiments, so must be inferred with reference to a material having a well-determined, independently calibrated Hugoniot equation of state (up is obtained from the impact velocity in traditional shock experiments, and the combination of US and up yields the pressure-density equation of state for the sample). Application of a Mie-Grüneisen model shows that the isochoric specific heat for a given phase is: CV = (US - c0)2 {s2US (dTH/dUS) + γ0 c0 s (TH/US)}-1 with US = c0 + s up, and γ0 is the zero-pressure Grüneisen parameter (γ/V = constant is assumed here). This result is a generalization to TH-US variables of the Walsh and Christian (1955) formula for the temperature rise along the Hugoniot of a given phase (identified here with a US - up relation that is locally linear); it can be analytically integrated to give TH(US) in terms of an average value of CV, if no phase transition takes place. Analysis of the TH-US slopes obtained from laser-shock measurements on MgO yields specific-heat values ranging from 1.02 (± 0.05) kJ/kg/K at 320-345 GPa and TH = 7700-9000 K to 1.50 (± 0.05) kJ/kg/K at 350-380 GPa and TH = 8700-9500 K. A fit to the absolute values of TH(US) in this pressure-temperature range gives CV = 1.26 (± 0.10) kJ/kg/K, in good accord with the Dulong-Petit value CV = 1.24 kJ/kg/K.

  17. Proposal for continuing studies on lead/scintillating fibres calorimetry (LFC)

    CERN Document Server

    Anzivino, Giuseppina; Bari, G; Basile, M; Bellagamba, L; Bencheikh, C; Boscherini, D; Bruni, G; Bruni, P; Buzuloiu, V; Cara Romeo, G; Chiarini, M; Cifarelli, Luisa; Cindolo, F; Ciralli, F; Contin, A; Dardo, M; De Pasquale, S; DeSalvo, R; Frasconi, F; Gheorghe, A; Giusti, P; Hao, E; Iacobucci, G; Laurenti, G; Lundin, M; Maccarrone, G D; Margotti, A; Massam, Thomas; Mondardini, M R; Nania, R; Peskov, Vladimir; Sartorelli, G; Scioni, M; Timellini, R; Wang, Y; Xu, C; You, K; Zichichi, Antonino; CERN. Geneva. Detector Research and Development Committee

    1991-01-01

    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.

  18. 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.

  19. 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)

  20. SAXS/DSC/WAXD study of temperature evolution in nanocomposite polymer electrolytes with different nanofillers.

    Science.gov (United States)

    Turković, A; Dubcek, P; Juraić, K; Bernstorff, S

    2012-11-01

    Polymer electrolytes are nanostructured materials which are very attractive components for batteries and opto-electronic devices. (PEO)8ZnCl2 polymer electrolytes were prepared from PEO and ZnCl2. The nanocomposites (PEO)8ZnCI2 themselves contained TiO2, Al2O3, MgO, ZnO and V2O5 nanograins. In this work, the influence of the Al2O3, MgO and V2O5 nanograins on the morphology and ionic conductivity of the nanocomposite was systematically studied by transmission small-angle X-ray scattering simultaneously recorded with wide-angle X-ray diffraction and differential scanning calorimetry at the synchrotron ELETTRA (Trieste, Italy). These three measurement methods yielded insight into the temperature-dependent changes of the grains of the electrolyte. The heating and cooling rate was 0.5 degrees C/min. Environment friendly galvanic cells as well as solar cells of the second generation are to be constructed with such nanocomposite polymer as electrolyte.

  1. 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%.

  2. DSC study of phase transition of anhydrous phospholipid DHPC and influence of water content

    Institute of Scientific and Technical Information of China (English)

    王邦宁; 谈夫

    1997-01-01

    The phase transition behavior of 1,2-di-n-heptadecanoyl phosphatidylcholme (DHPC)with and without water has been studied by use of differential scanning calorimetry It was found by experiment that the glass transition occurred at first during the first heating of a sample of DHPC without water and then the sample underwent melting as an ordinary crystal.Therefore the sample of DHPC without water was a glassy crystal However,the DHPC sample crystallizing from melt was an ordinary crystal From the relationship between the total melting enthalpy Qf of freezable water and the water content h,it was concluded that the water contained in the DHPC samples might exist in three states recognizable thermodynamically.The water in the first state was an unfreezable water It was the water bound directly with the head groups of the phospholipid,i.e.the primary hydration water Every head group might bind seven such molecules of water.The water in the second state was the secondary hydration water,us melt ing point was

  3. 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.

  4. 差示扫描量热分析测定外掺氧化镁水泥浆体中的氢氧化镁%Determination of Magnesium Hydroxide in Cement Paste Added with Magnesia by Differential Scanning Calorimetry

    Institute of Scientific and Technical Information of China (English)

    陈福松; 徐玲玲

    2011-01-01

    This paper introduces the differential scanning calorimetry(DSC) incremental method which is used to determine magnesium hydroxide in cement paste added with magnesia and on this basis, proposes the once-incement method used to determine magnesium hydroxide also. Besides the paper evaluates the accuracy of these two methods by recovery rate. The result shows that the recovery rate of magnesium hydroxide in cement paste added with magnesia is more than 98.5% by DSC incremental method and more than 97.5% by once-incement method. Though the DSC incremental method has high accuracy in determination of magnesium hydroxide in cement paste added with magnesia and the once-incement method is slightly lower in accuracy, the once-incement method is superior to the DSC incremental method in simplified operation and can be used to determine magnesium hydroxide also.%本文介绍了一种利用差示扫描量热分析(DSC)测定外掺氧化镁水泥浆体中氢氧化镁(Mg(OH))的方法-DSC增量法,在DSC增量法基础上提出采用一次增量测定水泥浆体中Mg(OH),并用回收率评价了这两种方法的准确性.结果表明:DSC增量法测定水泥浆体中Mg(OH)的回收率大于98.5%,此法准确度较高,测定外掺氧化镁水泥浆体中Mg(OH)是可行的;一次增量法测定Mg(OH)的回收率为97.5%以上,准确度较DSC增量法略低,但此法操作简单,也可对水泥浆体中Mg(OH)进行定量测定.

  5. The use of DSC to study isothermal crystallization behavior of super bright polyester chips with high intrinsic viscosity%DSC法研究高粘度超有光聚酯切片的等温结晶

    Institute of Scientific and Technical Information of China (English)

    王玉合; 王树霞; 司虎; 戴钧明

    2012-01-01

    The crystallization behavior of PET with different intrinsic viscosity was investigated using differential scanning calorimetry(DSC).The results show that the cold crystallization peaks(T c) increased and the melting crystallization peaks(T mc) decreased with the intrinsic viscosity increasing.It also shows that Avrami equation was satisfying in describing the isothermal crystallization kinetics of polyesters.Half-time crystallization t 1 /2 increased with the intrinsic viscosity increasing in the same crystallization temperature.These illustrated PET crystallization speed decreased with the intrinsic viscotisy increasing.%采用差示扫描量热法(DSC)对自制不同特性粘数的超有光聚酯切片进行结晶行为研究。分析结果表明:特性粘数增加,冷结晶温度Tc升高,熔融结晶温度Tmc降低,即结晶变慢;等温结晶行为较好地符合了Avrami方程。在同样的结晶温度下,特性粘数升高,半结晶周期t1/2增加,结晶变慢;相同时间内随着聚酯样品特性粘数的升高,结晶速率变慢。

  6. Life Predication of Polypropylene Using Accelerated Aging Method Based Differential Scanning Calorimetry%DSC加速老化试验方法在PP寿命估算中的应用

    Institute of Scientific and Technical Information of China (English)

    孟鑫; 石靖; 裘志浩; 辛忠

    2012-01-01

    Arrhenius equation which showed the relationship between the oxidation induction time(OIT) and the aging temperature was established based on OIT measured under different temperature by using differential scanning calorimetry (DSC) accelerated aging test method, and the OIT of polypropylene at different temperature was quickly estimated by using Arrhenius equation. The results showed that the estimates based on Arrhenius equation was effective, which was a good method for screening antioxidant formula.%利用差示扫描量热( DSC)加速老化试验方法,以不同温度下测得的氧化诱导时间(OIT)为基础,建立温度寿命相关的阿伦尼乌斯方程,并以此对不同温度下聚丙烯的寿命进行快速估算.结果表明,其估算结果有效,是筛选抗氧剂配方的一种较好的方法.

  7. Low temperature (down to 450 C) annealed TiAl contacts on N-type gallium nitride characterized by differential scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Thierry-Jebali, Nicolas [Laboratoire des Multimateriaux et Interfaces, UMR-CNRS 5615, Universite Claude Bernard Lyon 1, 43 Boulevard du 11 Novembre 1918, 69622 Villeurbanne Cedex (France); STMicroelectronics, R and D department, 11 rue Pierre et Marie Curie, 37100 Tours (France); Menard, Olivier [STMicroelectronics, R and D department, 11 rue Pierre et Marie Curie, 37100 Tours (France); Laboratoire de Microelectronique de Puissance, Universite Francois Rabelais de Tours, 1 rue Pierre et Marie Curie, 37100 Tours (France); Chiriac, Rodica; Brylinski, Christian [Laboratoire des Multimateriaux et Interfaces, UMR-CNRS 5615, Universite Claude Bernard Lyon 1, 43 Boulevard du 11 Novembre 1918, 69622 Villeurbanne Cedex (France); Collard, Emmanuel [STMicroelectronics, R and D department, 11 rue Pierre et Marie Curie, 37100 Tours (France); Cayrel, Frederic; Alquier, Daniel [Laboratoire de Microelectronique de Puissance, Universite Francois Rabelais de Tours, 1 rue Pierre et Marie Curie, 37100 Tours (France)

    2011-02-15

    This work reports on Differential Scanning Calorimetry (DSC) measurements performed on Ti-Al metallic layers stacks deposited on n{sup +}-GaN. The aim is to get better understanding of the mechanisms leading to ohmic contact formation during the annealing stage. Two exothermic peaks were found, one below 500 C and the other one around 660 C. They can be respectively attributed to Al{sub 3}Ti and Al{sub 2}Ti compounds formation. The locations of these peaks provide clear evidence of solid-solid reactions. Lowest contact resistance is well correlated with the presence of Al{sub 3}Ti compound, corresponding to Al(200nm)/Ti(50nm) stoichiometric ratio. Subsequently, Al(200 nm)Ti(50 nm) stacks on n{sup +}-GaN were annealed from 400 C to 650 C. Specific Contact Resistivity (SCR) values stay in the mid 10{sup -5} {omega}.cm{sup 2} range for annealing temperatures between 450 C and 650 C. Such low-temperature annealed contacts on n+-GaN may open new device processing routes, simpler and cheaper, in which Ohmic and Schottky contacts are annealed together. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. 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.

  9. Thermotropic phase behaviour of alpha-dipalmitoylphosphatidylcholine multibilayers is influenced to various extents by carotenoids containing different structural features--evidence from differential scanning calorimetry.

    Science.gov (United States)

    Kostecka-Gugała, Anna; Latowski, Dariusz; Strzałka, Kazimierz

    2003-01-31

    Carotenoids are the effective modulators of physical properties of model and natural membranes. To demonstrate the relationship between the structure of carotenoids and their effect on the molecular dynamics of membranes, we have investigated the influence of five structurally different carotenoids: beta-carotene, lycopene, lutein, violaxanthin, zeaxanthin and additionally carotane--a fully saturated derivative of beta-carotene, on thermotropic phase behaviour of dipalmitoylphosphatidylcholine (DPPC) multilamellar vesicles by means of differential scanning calorimetry (DSC). The results obtained indicate that the carotenoids used modulated the thermotropic properties of multibilayers to various extents, broadening the pretransition and the main phase transition peaks and shifting them to lower temperatures. Pronounced decrease of pretransition enthalpy (DeltaH(p)) proves that carotenoids very strongly alter the membrane properties in its gel phase. Comparison of the influence of several carotenoids shows that a rigid, polyisoprenoid chain plays a basic role in altering the thermotropic properties of such membranes and the presence of rings without oxygen-containing groups has a minor significance for the observed interactions. Carotenoids containing epoxy and/or hydroxy groups attached to their rings modify the thermotropic phase behaviour of DPPC multilamellar vesicles stronger than carotenes--a result of their orientation in the DPPC bilayer.

  10. 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.

    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...... of the 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.......35. In the fluid phase increasing X-cer from 0.06 to 0.35 augments d from 61 Angstrom to 64 Angstrom. An L-beta/L-alpha (ripple/fluid) phase coexistence region is observed at high temperatures (from 31 to 56.5 degrees C) when X-cer > 0.03. With cooling from temperatures above 50 degrees C we observe a slow...

  11. Identification and quantification of the crystalline structures of poly(vinylidene fluoride) sutures by wide-angle X-ray scattering and differential scanning calorimetry.

    Science.gov (United States)

    Laroche, G; Lafrance, C P; Prud'homme, R E; Guidoin, R

    1998-02-01

    The outstanding biocompatibility of the polyvinylidene fluoride (PVDF) monofilament suture together with other desirable characteristics, such as ease of handling and resistance to biodegradation, makes it an attractive alternative monofilament suture material for cardiovascular surgery. However, to achieve a high performance suture, the polymeric raw material must be exposed to different treatments, which lead to different degrees and types of crystallization. Since these crystalline modifications deeply influence the mechanical characteristics and the biostability of the sutures, the authors hereby propose a method of quantifying the different structures of PVDF using wide angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). The commercial devices are achieved by coloring and processing the polymeric raw material. The white and unprocessed 4-0 unswaged suture presents 19% of the alpha phase, 38% of the beta structure, and no gamma form. Coloration increases the amount of the beta phase by 5-9% at the expense of the alpha phase. On the other hand, processing the fibers lead to the conversion of some of the amorphous phase to the gamma structure, the importance of which is 6-7%. Finally, tensile measurements performed on the different PVDF fibers clearly proves that their mechanical characteristics depend on the presence of these crystalline forms in the polymeric structure of PVDF.

  12. Entalpia reticular, entalpia de fusão e temperatura de fusão de adutos: algumas correlações empíricas utilizando DSC

    Directory of Open Access Journals (Sweden)

    Farias Robson Fernandes de

    1999-01-01

    Full Text Available By using DSC data is shown that there are empirical correlations between lattice enthalpy, melting enthalpy and the temperature of melting for adducts, and that is possible, using only a single DSC curve, estimate the value of DM Hmq.

  13. Analysis of the Pipe Heat Loss of the Water Flow Calorimetry System in EAST Neutral Beam Injector

    Science.gov (United States)

    Hu, Chundong; Chen, Yu; Xu, Yongjian; Yu, Ling; Li, Xiang; Zhang, Weitang

    2016-11-01

    Neutral beam injection heating is one of the main auxiliary heating methods in controllable nuclear fusion research. In the EAST neutral beam injector, a water flow calorimetry (WFC) system is applied to measure the heat load on the electrode system of the ion source and the heat loading components of the beamline. Due to the heat loss in the return water pipe, there are some measuring errors for the current WFC system. In this paper, the errors were measured experimentally and analyzed theoretically, which lay a basis for the exact calculation of beam power deposition distribution and neutralization efficiency. supported by the National Magnetic Confinement Fusion Science Program of China (No. 2013GB101001) and the International Science & Technology Cooperation Program of China (No. 2014DFG61950)

  14. 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

    at 60°C/0% RH and dissolution studies (non-sink conditions) were performed on the milled glibenclamide samples. Different milling durations were needed to render glibenclamide fully amorphous according to Raman spectroscopy (60min) and onset of crystallisation using DSC (150min). This could be due...... to 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 duration...... and plateaus were reached after milling for certain periods of time (physical stability - 150min; dissolution - 120min). The residual crystallinity which was detectable with DSC (onset of crystallisation), but not with Raman spectroscopy, adversely affected the critical quality attributes of milled...

  15. Experimental analysis on the coupled effect between thermo-optical properties and microstructure of semi-crystalline thermoplastics

    Science.gov (United States)

    Boztepe, Sinan; Thiam, Abdoulahad; de Almeida, Olivier; Le Maoult, Yannick; Schmidt, Fabrice

    2016-10-01

    Radiation heat transfer is the most common method used in thermoforming processes of thermoplastic polymers due to their poor thermal conductivity. Considering the fact that the thermo-optical characteristics of polymers play a major role in the efficiency of radiative heat transfer in bulk polymers, microstructure of semi-crystalline thermoplastics is one of the key factors to understand this heat transfer phenomenon in depth. In this study, a relation between the microcrystalline structure of polyolefin (PO) and its effect on the thermo-optical properties was experimentally analyzed. Information on the microcrystalline structure of the samples was obtained by determining the degree of crystallinity (Xc) thanks to Differential Scanning Calorimetry (DSC). Using Fourier Transform Infrared (FT-IR) spectroscopy and integrating sphere, optical characteristics of the PO samples were analyzed considering two spectrums that are in near-infrared (NIR) and middle-infrared (MIR) spectral regions respectively. The analyses showed that the degree of crystallinity has a great effect on the thermo-optical characteristics of the PO - particularly considering transmission - in NIR range. Such a coupled effect can be functionalized and adopted to develop an advanced radiative heat transfer model that may be used for addressing various problems on infrared (IR) heating of heterogeneous materials, particularly semi-crystalline thermoplastics. In the last part of the paper, a theoretical approach for consideration of the heterogeneity of semi-crystalline thermoplastics in a radiative heat transfer model was highlighted.

  16. 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.

  17. Experimental determination of the H2SO4/(NH4)2SO4/H2O phase diagram.

    Science.gov (United States)

    Beyer, Keith D; Bothe, Jameson R; Burrmann, Nicola

    2007-01-25

    We have experimentally investigated the water and sulfuric acid-rich regions of the H2SO4/(NH4)2SO4/H2O ternary liquid/solid phase diagram using differential scanning calorimetry (DSC) and infrared spectroscopy of thin films. We present the liquid/solid ternary phase diagram for temperatures below 373 K and H2SO4 concentrations below 60 wt %. We have determined two ternary eutectics and two tributary reaction points for this system in the regions studied. It is also seen that sulfuric acid tetrahydrate (SAT) forms as a metastable solid over a large concentration range. Two true binary systems have been identified: ice/letovicite and SAT/ammonium bisulfate. Finally, we have compared our results to the predictions of the aerosol inorganics model and have found significant differences both in the final melting points and in the location of some of the phase boundaries including a significant discrepancy in the invariant points predicted versus those observed.

  18. Pengaruh pengawetan kulit ikan buntal (Arothon reticularis terhadap suhu kerut ditinjau melalui analisis differential scanning calorimeter (DSC

    Directory of Open Access Journals (Sweden)

    RLM. Satrio Ari Wibowo

    2015-12-01

    Full Text Available The aim of this study was to determine the effect of the skin preservation type against shrinkage temperature of leather. The material used in this study was the skin of pufferfish (Arothon reticularis that have been preserved by salting, formaldehyde and pickling and also raw skin as a reference. The method used to measure the shrinkage temperature was thermal analysis using Differential Scanning Calorimeter (DSC that operated from 4°C up to 440°C with nitrogen stream. DSC measurement results showed that shrinkage temperature of puffer fish preserved with formaldehyde was higher than salting and pickling, which is 63.64°C; 47.95°C; 57.37oC respectively. The advantage of using formaldehyde compared to others preservation technique was not only can protect the skin from damage by microorganisms, but also can create a bond with the collagen .

  19. Enzyme kinetics determined by single-injection isothermal titration calorimetry.

    Science.gov (United States)

    Transtrum, Mark K; Hansen, Lee D; Quinn, Colette

    2015-04-01

    The purposes of this paper are (a) to examine the effect of calorimeter time constant (τ) on heat rate data from a single enzyme injection into substrate in an isothermal titration calorimeter (ITC), (b) to provide information that can be used to predict the optimum experimental conditions for determining the rate constant (k2), Michaelis constant (KM), and enthalpy change of the reaction (ΔRH), and (c) to describe methods for evaluating these parameters. We find that KM, k2 and ΔRH can be accurately estimated without correcting for the calorimeter time constant, τ, if (k2E/KM), where E is the total active enzyme concentration, is between 0.1/τ and 1/τ and the reaction goes to at least 99% completion. If experimental conditions are outside this domain and no correction is made for τ, errors in the inferred parameters quickly become unreasonable. A method for fitting single-injection data to the Michaelis-Menten or Briggs-Haldane model to simultaneously evaluate KM, k2, ΔRH, and τ is described and validated with experimental data. All four of these parameters can be accurately inferred provided the reaction time constant (k2E/KM) is larger than 1/τ and the data include enzyme saturated conditions.

  20. A novel compound DSC suppresses lipopolysaccharide-induced inflammatory responses by inhibition of Akt/NF-κB signalling in macrophages.

    Science.gov (United States)

    Liu, Xin-Hua; Pan, Li-Long; Jia, Yao-Ling; Wu, Dan; Xiong, Qing-Hui; Wang, Yang; Zhu, Yi-Zhun

    2013-05-15

    A novel compound [4-(2-acetoxy-3-((R)-3-(benzylthio)-1-methoxy-1-oxopropan-2-ylamino)-3-oxopropyl)-1,2-phenylene diacetate (DSC)], derived from Danshensu, exerted cytoprotective effects by anti-oxidative and anti-apoptotic activities in vitro. Herein, we reported the protective effects of DSC on lipopolysaccharide (LPS)-induced inflammatory responses in murine RAW264.7 macrophages and the underlying mechanisms. We showed that DSC concentration-dependently attenuated nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) expression with less cytotoxicity. Signal transduction studies indicated that DSC significantly inhibited LPS-induced phosphorylation of Akt, but not c-Jun N-terminal kinase 1/2, p38, or extracellular signal-regulated kinase 1/2. Meanwhile, LPS-induced nuclear translocation of nuclear factor-κB (NF-κB) p65 was decreased by DSC. Furthermore, a phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 significantly suppressed LPS-induced NF-κB p65 nuclear translocation, iNOS expression, and NO production, which was also mimicked by pretreatment with DSC. These results suggested that DSC attenuated LPS-induced inflammatory response in macrophages, at least in part, through suppression of PI3K/Akt signaling and NF-κB activation.

  1. 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

  2. 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)

  3. The photothermoelectric technique (PTE), an alternative photothermal calorimetry

    Science.gov (United States)

    Dadarlat, D.; Streza, M.; King, R. Chan Yu; Roussel, F.; Kuriakose, M.; Depriester, M.; Guilmeau, E.; Sahraoui, A. Hadj

    2014-01-01

    The recently introduced photothermoelectric (PTE) effect is proposed as an alternative for measuring dynamic thermal parameters of solid samples. The front PTE configuration, together with the thermal-wave resonator cavity method as a scanning procedure, was used to measure the value of thermal effusivity. The back PTE configuration, together with the chopping frequency of incident radiation as a scanning parameter, leads to the direct measurement of thermal diffusivity. A theory based on the above two detection configurations was developed and its application to solids, covering a large range of typical values of thermal parameters (aluminum and copper alloys, glass, teflon, polyethylene, LiTaO3), was described in order to demonstrate the suitability of the method. Experimental support for other well-known techniques (photopyroelectric and infrared lock-in thermography) has validated the results obtained with the novel method.

  4. Isothermal Titration Calorimetry Measurements of Metal Ions Binding to Proteins.

    Science.gov (United States)

    Quinn, Colette F; Carpenter, Margaret C; Croteau, Molly L; Wilcox, Dean E

    2016-01-01

    ITC measurements involving metal ions are susceptible to a number of competing reactions (oxidation, precipitation, and hydrolysis) and coupled reactions involving the buffer and protons. Stabilization and delivery of the metal ion as a well-defined and well-characterized complex with the buffer, or a specific ligand, can suppress undesired solution chemistry and, depending on the stability of the metal complex, allow accurate measurements of higher affinity protein-binding sites. This requires, however, knowledge of the thermodynamics of formation of the metal complex and accounting for its contribution to the experimentally measured values (KITC and ΔHITC) through a post hoc analysis that provides the condition-independent binding thermodynamics (K, ΔG(o), ΔH, ΔS, and ΔCP). This analysis also quantifies the number of protons that are displaced when the metal ion binds to the protein.

  5. HE calorimetry. Quarterly report, April--June, 1969

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval, J.

    1969-12-31

    The 48-inch detonation sphere confined the gaseous products resulting from the discharge of approximately one-half pound (225 g) of an HE (PETN) under investigation. Product analysis, combined with calorimetric measurements will provide data regarding the detonation processes. Results of the initial HE detonation are still in the process of evaluation and tabulation. The final summary of this information will be instrumental in the direction of future experimental endeavor. Investigation at Pantex will be in collaboration with and guided by the research in progress at LRL. A new lid, still in the design stage, must be fabricated to make the detonation sphere compatible with the anticipated need in the testing of future explosives. This will necessitate the modification of the vacuum lines, but the extent of this modification is not known at this time.

  6. Isothermal titration calorimetry in nanoliter droplets with subsecond time constants.

    Science.gov (United States)

    Lubbers, Brad; Baudenbacher, Franz

    2011-10-15

    We reduced the reaction volume in microfabricated suspended-membrane titration calorimeters to nanoliter droplets and improved the sensitivities to below a nanowatt with time constants of around 100 ms. The device performance was characterized using exothermic acid-base neutralizations and a detailed numerical model. The finite element based numerical model allowed us to determine the sensitivities within 1% and the temporal dynamics of the temperature rise in neutralization reactions as a function of droplet size. The model was used to determine the optimum calorimeter design (membrane size and thickness, junction area, and thermopile thickness) and sensitivities for sample volumes of 1 nL for silicon nitride and polymer membranes. We obtained a maximum sensitivity of 153 pW/(Hz)(1/2) for a 1 μm SiN membrane and 79 pW/(Hz)(1/2) for a 1 μm polymer membrane. The time constant of the calorimeter system was determined experimentally using a pulsed laser to increase the temperature of nanoliter sample volumes. For a 2.5 nanoliter sample volume, we experimentally determined a noise equivalent power of 500 pW/(Hz)(1/2) and a 1/e time constant of 110 ms for a modified commercially available infrared sensor with a thin-film thermopile. Furthermore, we demonstrated detection of 1.4 nJ reaction energies from injection of 25 pL of 1 mM HCl into a 2.5 nL droplet of 1 mM NaOH.

  7. 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

  8. 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 thermal pulse to approx. 600 C experienced by ALH84001. Here, we

  9. Experimental determination of the temperature dependence of water activities for a selection of aqueous organic solutions

    Directory of Open Access Journals (Sweden)

    G. Ganbavale

    2014-05-01

    Full Text Available This work presents experimental data of the temperature dependence of water activity in aqueous organic solutions relevant for tropospheric conditions (200–273 K. Water activity (aw at low temperatures (T is a crucial parameter for predicting homogeneous ice nucleation. We investigated temperature dependent water activities, ice freezing and melting temperatures of solutions, and vapour pressures of a selection of atmospherically relevant aqueous organic systems. To measure aw over a wide composition range and with a focus on low temperatures, we use various aw measurement techniques and instruments: a dew point water activity meter, an electrodynamic balance (EDB, differential scanning calorimetry (DSC, and a setup to measure the total gas phase pressure at equilibrium over aqueous solutions. Water activity measurements were performed for aqueous multicomponent and multifunctional organic mixtures containing the functional groups typically found in atmospheric organic aerosols, such as hydroxyl, carboxyl, ketone, ether, ester, and aromatic groups. The aqueous organic systems studied at several fixed compositions over a considerable temperature range differ significantly in their temperature dependence. Aqueous organic systems of 1,4-butanediol and methoxyacetic acid show a moderate decrease in aw with decreasing temperature. The aqueous M5 system (a multicomponent system containing five different dicarboxylic acids and aqueous 2-(2-ethoxyethoxyethanol solutions both show a strong increase of water activity with decreasing temperature at high solute concentrations for TTaw can be reversed at low temperatures and that linear extrapolations of high temperature data may lead to erroneous predictions. To avoid this, experimentally determined aw at low temperature are needed to improve thermodynamic models towards lower temperatures and for improved predictions of the ice nucleation ability of organic–water systems.

  10. Low-temperature transitions in cod and tuna determined by differential scanning calorimetry

    DEFF Research Database (Denmark)

    Jensen, Kristina Nedenskov; Jørgensen, Bo; Nielsen, Jette

    2003-01-01

    Differential scanning calorimetry measurements have revealed different thermal transitions in cod and tuna samples. Transition temperatures detected Lit -11degreesC, -15degreesC and -21degreesC were highly dependent on the annealing temperature. In tuna muscle an additional transition was observe...

  11. 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...

  12. 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

    in 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...

  13. 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…

  14. Thermoreversible gelation of cellulose acetate solutions studied by differential scanning calorimetry

    NARCIS (Netherlands)

    Altena, F.W.; Schroder, J.S.; Huls, van de R.; Smolders, C.A.

    1986-01-01

    Thermoreversible gels of cellulose acetate can be obtained by cooling concentrated cellulose acetate solutions in solvent-nonsolvent mixtures of dioxane and water. Upon heating the gels, endothermic effects were observed with differential scanning calorimetry. The heat effects are ascribed to the me

  15. 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.

  16. 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…

  17. 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.

  18. Isoquinoline alkaloids and their binding with DNA: calorimetry and thermal analysis applications.

    Science.gov (United States)

    Bhadra, Kakali; Kumar, Gopinatha Suresh

    2010-11-01

    Alkaloids are a group of natural products with unmatched chemical diversity and biological relevance forming potential quality pools in drug screening. The molecular aspects of their interaction with many cellular macromolecules like DNA, RNA and proteins are being currently investigated in order to evolve the structure activity relationship. Isoquinolines constitute an important group of alkaloids. They have extensive utility in cancer therapy and a large volume of data is now emerging in the literature on their mode, mechanism and specificity of binding to DNA. Thermodynamic characterization of the binding of these alkaloids to DNA may offer key insights into the molecular aspects that drive complex formation and these data can provide valuable information about the balance of driving forces. Various thermal techniques have been conveniently used for this purpose and modern calorimetric instrumentation provides direct and quick estimation of thermodynamic parameters. Thermal melting studies and calorimetric techniques like isothermal titration calorimetry and differential scanning calorimetry have further advanced the field by providing authentic, reliable and sensitive data on various aspects of temperature dependent structural analysis of the interaction. In this review we present the application of various thermal techniques, viz. isothermal titration calorimetry, differential scanning calorimetry and optical melting studies in the characterization of drug-DNA interactions with particular emphasis on isoquinoline alkaloid-DNA interaction.

  19. NorLeu3-Angiotensin (1-7) [DSC127] as a Therapy for the Healing of Diabetic Foot Ulcers

    Science.gov (United States)

    Rodgers, Kathleen E.; Bolton, Laura L.; Verco, Shelagh; diZerega, Gere S.

    2015-01-01

    Significance: Diabetes is a disorder that is well known to delay wound repair resulting in the formation of colonized chronic wounds. Over their lifetime, diabetic patients have a 25% incidence of foot ulcers (DFUs), which contribute to increased risk of morbidity, including osteomyelitis and amputations, and increased burden to the healthcare system. Recent Advances: The only active product approved for the treatment of diabetic ulcers, Regranex®, is not widely used due to minimal proven efficacy and recent warnings added to the Instructions for Use. A novel topical agent that accelerates healing and increases the proportion of fully healed DFUs, DSC127 [aclerastide; active ingredient, NorLeu3-angiotensin (1-7) (NorLeu3-A(1-7))], is recruiting patients in Phase III clinical trials (NCT01830348 and NCT01849965). NorLeu3-A(1-7) is an analog of the naturally occurring peptide, angiotensin 1-7. The mechanisms of action include induction of progenitor proliferation, accelerated vascularization, collagen deposition, and re-epithelialization. Critical Issues: Current modalities for the treatment of DFUs include strict offloading, bandaging, debridement and, on a limited basis, application of Regranex. Novel potent therapies are needed to combat this significant burden to the diabetic patient and the healthcare system. Future Direction: Preclinical and clinical research shows that DSC127 is highly effective in the closure of diabetic wounds and is superior to Regranex in animal studies. Clinical development of DSC127 as a topical agent for the healing of DFU is underway. Further investigation into the mechanisms by which this product accelerates healing is warranted. PMID:26029484

  20. DSC法测试PCB之Tg的影响因素探讨%Discussion on the influence factors of using DSC to test Tg of PCB

    Institute of Scientific and Technical Information of China (English)

    陈小飞; 方军良

    2013-01-01

    在PCB行业中,DSC法主要用来测定PCB基板的玻璃化转变温度和固化度,运用DSC法测试PCB的Tg时,影响测试结果的因素有很多。文章重点对运用DSC法测试PCB的Tg过程中存在的影响因素分类进行讨论分析。%This paper mainly introduces DSC (differential scanning calorimeter), one of thermal analysis method. In the PCB industry, DSC technology is mainly used to test the glass transition temperature and curing degree of PCB. Using DSC method to test the glass transition temperature of PCB, there are many factors that influence the test result. This paper focuses on discussing and analyzing the influence factors which exists in the process of the test of glass transition temperature of PCB by DSC method.

  1. Dysspondyloenchondromatosis (DSC) associated with COL2A1 mutation: Clinical and radiological overlap with spondyloepimetaphyseal dysplasia-Strudwick type (SEMD-S).

    Science.gov (United States)

    Merrick, Blair; Calder, Alistair; Wakeling, Emma

    2015-12-01

    Dysspondyloenchondromatosis (DSC) is a rare skeletal dysplasia characterized by enchondroma-like lesions and anisospondyly. The former leads to discrepancies in limb length, and the latter, to progressive kyphoscoliosis. Two recent cases have highlighted the genetic heterogeneity of DSC, one demonstrating the presence and, the other, the absence of a COL2A1 mutation. This may have important clinical implications, for example, screening for complications including atlanto-axial instability associated with type II collagenopathies, as well as long-term patient management. We report on a case with radiographic features of DSC with overlap into the type II collagenopathy spondyloepimetaphyseal dysplasia, Strudwick type, who was found to carry a novel heterozygous mutation in the COL2A1 gene. Testing for COL2A1 mutations should be performed in all patients with radiological features of DSC. Further research is needed to identify the underlying molecular cause in cases where no COL2A1 mutation is identified.

  2. 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.

  3. 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

  4. Collecting variable-concentration isothermal titration calorimetry datasets in order to determine binding mechanisms.

    Science.gov (United States)

    Freiburger, Lee A; Mittermaier, Anthony K; Auclair, Karine

    2011-04-07

    Isothermal titration calorimetry (ITC) is commonly used to determine the thermodynamic parameters associated with the binding of a ligand to a host macromolecule. ITC has some advantages over common spectroscopic approaches for studying host/ligand interactions. For example, the heat released or absorbed when the two components interact is directly measured and does not require any exogenous reporters. Thus the binding enthalpy and the association constant (Ka) are directly obtained from ITC data, and can be used to compute the entropic contribution. Moreover, the shape of the isotherm is dependent on the c-value and the mechanistic model involved. The c-value is defined as c = n[P]tKa, where [P]t is the protein concentration, and n is the number of ligand binding sites within the host. In many cases, multiple binding sites for a given ligand are non-equivalent and ITC allows the characterization of the thermodynamic binding parameters for each individual binding site. This however requires that the correct binding model be used. This choice can be problematic if different models can fit the same experimental data. We have previously shown that this problem can be circumvented by performing experiments at several c-values. The multiple isotherms obtained at different c-values are fit simultaneously to separate models. The correct model is next identified based on the goodness of fit across the entire variable-c dataset. This process is applied here to the aminoglycoside resistance-causing enzyme aminoglycoside N-6'-acetyltransferase-Ii (AAC(6')-Ii). Although our methodology is applicable to any system, the necessity of this strategy is better demonstrated with a macromolecule-ligand system showing allostery or cooperativity, and when different binding models provide essentially identical fits to the same data. To our knowledge, there are no such systems commercially available. AAC(6')-Ii, is a homo-dimer containing two active sites, showing cooperativity between

  5. Enhanced thermal property measurement of a silver zinc battery cell using isothermal calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Ubelhor, Ryan, E-mail: ryan.ubelhor@navy.mil [Naval Surface Warfare Center, Crane Division, 300 Highway 361, Crane, IN 47522 (United States); Ellison, Daniel [Science Applications International Corporation, 300 Highway 361, Crane, IN 47522 (United States); Pierce, Cecilia [Naval Surface Warfare Center, Crane Division, 300 Highway 361, Crane, IN 47522 (United States)

    2015-04-20

    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

  6. 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.

  7. The retrogradation properties of glutinous rice and buckwheat starches as observed with FT-IR, 13C NMR and DSC.

    Science.gov (United States)

    Lian, Xijun; Wang, Changjun; Zhang, Kunsheng; Li, Lin

    2014-03-01

    The experiment was conducted to study the retrogradation properties of glutinous rice and buckwheat starch with wavelengths of maximum absorbance, FT-IR, (13)C NMR, and DSC. The results show that the starches in retrograded glutinous rice starch and glutinous rice amylopectin could not form double helix. The IR results show that protein inhabits in glutinous rice and maize starches in a different way and appearance of C-H symmetric stretching vibration at 2852 cm(-1) in starch might be appearance of protein. Retrogradation untied the protein in glutinous amylopectin. Enthalpies of sweet potato and maize granules are higher than those of their retrograded starches. The (13)C NMR results show that retrogradation of those two starches leads to presence of β-anomers and retrogradation might decompose lipids in glutinous rice amylopectin into small molecules. Glutinous rice starch was more inclined to retrogradation than buckwheat starch. The DSC results show that the second peak temperatures for retrograded glutinous rice and buckwheat starches should be assigned to protein. The SEM results show that an obvious layer structure exists in retrograded glutinous rice amylopectin.

  8. An efficient computational approach to characterize DSC-MRI signals arising from three-dimensional heterogeneous tissue structures.

    Science.gov (United States)

    Semmineh, Natenael B; Xu, Junzhong; Boxerman, Jerrold L; Delaney, Gary W; Cleary, Paul W; Gore, John C; Quarles, C Chad

    2014-01-01

    The systematic investigation of susceptibility-induced contrast in MRI is important to better interpret the influence of microvascular and microcellular morphology on DSC-MRI derived perfusion data. Recently, a novel computational approach called the Finite Perturber Method (FPM), which enables the study of susceptibility-induced contrast in MRI arising from arbitrary microvascular morphologies in 3D has been developed. However, the FPM has lower efficiency in simulating water diffusion especially for complex tissues. In this work, an improved computational approach that combines the FPM with a matrix-based finite difference method (FDM), which we call the Finite Perturber the Finite Difference Method (FPFDM), has been developed in order to efficiently investigate the influence of vascular and extravascular morphological features on susceptibility-induced transverse relaxation. The current work provides a framework for better interpreting how DSC-MRI data depend on various phenomena, including contrast agent leakage in cancerous tissues and water diffusion rates. In addition, we illustrate using simulated and micro-CT extracted tissue structures the improved FPFDM along with its potential applications and limitations.

  9. Determination of microplastic polyethylene (PE) and polypropylene (PP) in environmental samples using thermal analysis (TGA-DSC).

    Science.gov (United States)

    Majewsky, Marius; Bitter, Hajo; Eiche, Elisabeth; Horn, Harald

    2016-10-15

    Microplastics are increasingly detected in the environment and the consequences on water resources and ecosystems are not clear to date. The present study provides a cost-effective and straightforward method to determine the mass concentrations of polymer types using thermal analysis. Characteristic endothermic phase transition temperatures were determined for seven plastic polymer types using TGA-DSC. Based on that, extracts from wastewater samples were analyzed. Results showed that among the studied polymers, only PE and PP could be clearly identified, while the phase transition signals of the other polymers largely overlap each other. Subsequently, calibration curves were run for PE and PP for qualitative measurements. 240 and 1540mg/m(3) of solid material (12µm to 1mm) was extracted from two wastewater effluent samples of a municipal WWTP of which 34% (81mg/m(3)) and 17% (257mg/m(3)) could be assigned to PE, while PP was not detected in any of the samples. The presented application of TGA-DSC provides a complementary or alternative method to FT-IR analyses for the determination of PE and PP in environmental samples.

  10. Formation of cholesterol bilayer domains precedes formation of cholesterol crystals in cholesterol/dimyristoylphosphatidylcholine membranes: EPR and DSC studies.

    Science.gov (United States)

    Mainali, Laxman; Raguz, Marija; Subczynski, Witold K

    2013-08-01

    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 analogues, it was shown that the CBDs begin to form at ~50 mol % cholesterol. It was confirmed by DSC that the cholesterol solubility threshold for DMPC membranes is detected at ~66 mol % cholesterol. At levels above this cholesterol content, monohydrate cholesterol crystals start to form. The major finding is that the formation of CBDs precedes formation of cholesterol crystals. The region of the phase diagram for cholesterol contents between 50 and 66 mol % is described as a structured one-phase region in which CBDs have to be supported by the surrounding DMPC bilayer saturated with cholesterol. Thus, the phase boundary located at 66 mol % cholesterol separates the structured one-phase region (liquid-ordered phase of DMPC with CBDs) from the two-phase region where the structured liquid-ordered phase of DMPC coexists with cholesterol crystals. It is likely that CBDs are precursors of monohydrate cholesterol crystals.

  11. Experimental Study of the Interaction between Recrystallization and Precipitation Processes of an AA8011 Commercial Alloy

    Directory of Open Access Journals (Sweden)

    Ney José Luiggi

    2014-01-01

    Full Text Available Phase changes in a commercial AA8011 alloy from different initial microstructure conditions were studied using thermoelectric power (ΔS, differential scanning calorimetry (DSC, and transmission electron microscopy (TEM techniques with the purpose of obtaining evidence of the interaction between recovery-precipitation and recrystallization-precipitation processes occurring during nonisothermal heating at different rates. Thermoelectric power and its thermal derivative reflect this evidence by a displacement of the characteristic precipitation peaks, the recovery and recrystallization contributions remaining masked by the strong incidence of the iron precipitation on that property, while DSC measurements detect the emergence of new peaks not observed on thermograms of homogenized samples. An exhaustive study of these peaks permits direct differentiation between precipitation and recovery-recrystallization contributions. TEM confirms the interaction between both processes by means of local observations.

  12. PHOENIX: a scoring function for affinity prediction derived using high-resolution crystal structures and calorimetry measurements.

    Science.gov (United States)

    Tang, Yat T; Marshall, Garland R

    2011-02-28

    Binding affinity prediction is one of the most critical components to computer-aided structure-based drug design. Despite advances in first-principle methods for predicting binding affinity, empirical scoring functions that are fast and only relatively accurate are still widely used in structure-based drug design. With the increasing availability of X-ray crystallographic structures in the Protein Data Bank and continuing application of biophysical methods such as isothermal titration calorimetry to measure thermodynamic parameters contributing to binding free energy, sufficient experimental data exists that scoring functions can now be derived by separating enthalpic (ΔH) and entropic (TΔS) contributions to binding free energy (ΔG). PHOENIX, a scoring function to predict binding affinities of protein-ligand complexes, utilizes the increasing availability of experimental data to improve binding affinity predictions by the following: model training and testing using high-resolution crystallographic data to minimize structural noise, independent models of enthalpic and entropic contributions fitted to thermodynamic parameters assumed to be thermodynamically biased to calculate binding free energy, use of shape and volume descriptors to better capture entropic contributions. A set of 42 descriptors and 112 protein-ligand complexes were used to derive functions using partial least-squares for change of enthalpy (ΔH) and change of entropy (TΔS) to calculate change of binding free energy (ΔG), resulting in a predictive r2 (r(pred)2) of 0.55 and a standard error (SE) of 1.34 kcal/mol. External validation using the 2009 version of the PDBbind "refined set" (n = 1612) resulted in a Pearson correlation coefficient (R(p)) of 0.575 and a mean error (ME) of 1.41 pK(d). Enthalpy and entropy predictions were of limited accuracy individually. However, their difference resulted in a relatively accurate binding free energy. While the development of an accurate and applicable

  13. 一种基于特征向量的改进DSC网页去重算法%An Improved DSC Removing Duplicated Webpages Algorithm Based on Feature Vector

    Institute of Scientific and Technical Information of China (English)

    徐朝辉; 赵淑梅; 闫付亮; 秦杰

    2013-01-01

    网页去重具有很重要的实际意义,也是信息检索领域近几年研究的热点.分析现有的网页去重算法,并对经典的DSC(digital syntactic clustering)网页去重算法进行改进.为每篇文档生成一个特征向量集合,用该特征向量集合筛选shingles;然后进行相似性比较.实验表明,该算法对重复网页判定具有很好的准确率和召回率.%Removing duplicated Webpages can improve the performance of search engines, and it has been one of research issues in todays information retrieving research. The main popular duplicated Webpages detecting methods is analysed, and algorithm is modified the traditional DSC to select the shingles through the feature vectors of the document, and then compared the similarity of two documents. The experimental results show that the method has achieved a good performance in recall and precision.

  14. 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.

  15. 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.

  16. Laser Calorimetry Spectroscopy for ppm-level Dissolved Gas Detection and Analysis

    Science.gov (United States)

    K. S., Nagapriya; Sinha, Shashank; Prashanth, R.; Poonacha, Samhitha; Chaudhry, Gunaranjan; Bhattacharya, Anandaroop; Choudhury, Niloy; Mahalik, Saroj; Maity, Sandip

    2017-02-01

    In this paper we report a newly developed technique – laser calorimetry spectroscopy (LCS), which is a combination of laser absorption spectroscopy and calorimetry - for the detection of gases dissolved in liquids. The technique involves determination of concentration of a dissolved gas by irradiating the liquid with light of a wavelength where the gas absorbs, and measuring the temperature change caused by the absorbance. Conventionally, detection of dissolved gases with sufficient sensitivity and specificity was done by first extracting the gases from the liquid and then analyzing the gases using techniques such as gas chromatography. Using LCS, we have been able to detect ppm levels of dissolved gases without extracting them from the liquid. In this paper, we show the detection of dissolved acetylene in transformer oil in the mid infrared (MIR) wavelength (3021 nm) region.

  17. Characterization of photomultiplier tubes in a novel operation mode for Secondary Emission Ionization Calorimetry

    Science.gov (United States)

    Tiras, E.; Dilsiz, K.; Ogul, H.; Southwick, D.; Bilki, B.; Wetzel, J.; Nachtman, J.; Onel, Y.; Winn, D.

    2016-10-01

    Hamamatsu single anode R7761 and multi-anode R5900-00-M16 Photomultiplier Tubes have been characterized for use in a Secondary Emission (SE) Ionization Calorimetry study. SE Ionization Calorimetry is a novel technique to measure electromagnetic shower particles in extreme radiation environments. The different operation modes used in these tests were developed by modifying the conventional PMT bias circuit. These modifications were simple changes to the arrangement of the voltage dividers of the baseboard circuits. The PMTs with modified bases, referred to as operating in SE mode, are used as an SE detector module in an SE calorimeter prototype, and placed between absorber materials (Fe, Cu, Pb, W, etc.). Here, the technical design of different operation modes, as well as the characterization measurements of both SE modes and the conventional PMT mode are reported.

  18. Determination of the catalytic activity of binuclear metallohydrolases using isothermal titration calorimetry.

    Science.gov (United States)

    Pedroso, Marcelo M; Ely, Fernanda; Lonhienne, Thierry; Gahan, Lawrence R; Ollis, David L; Guddat, Luke W; Schenk, Gerhard

    2014-03-01

    Binuclear metallohydrolases are a large and diverse family of enzymes that are involved in numerous metabolic functions. An increasing number of members find applications as drug targets or in processes such as bioremediation. It is thus essential to have an assay available that allows the rapid and reliable determination of relevant catalytic parameters (k cat, K m, and k cat/K m). Continuous spectroscopic assays are frequently only possible by using synthetic (i.e., nonbiological) substrates that possess a suitable chromophoric marker (e.g., nitrophenol). Isothermal titration calorimetry, in contrast, affords a rapid assay independent of the chromophoric properties of the substrate-the heat associated with the hydrolytic reaction can be directly related to catalytic properties. Here, we demonstrate the efficiency of the method on several selected examples of this family of enzymes and show that, in general, the catalytic parameters obtained by isothermal titration calorimetry are in good agreement with those obtained from spectroscopic assays.

  19. Effects of lipid membrane curvature on lipid packing state evaluated by isothermal titration calorimetry.

    Science.gov (United States)

    Yokoyama, Hirokazu; Ikeda, Keisuke; Wakabayashi, Masaki; Ishihama, Yasushi; Nakano, Minoru

    2013-01-22

    In this report, we present a novel approach for the elucidation of the physicochemical properties of lipid membranes by isothermal titration calorimetry (ITC) to quantify the heat absorbed during the solubilization of vesicles into TritonX-100 micelles. By using large and small unilamellar vesicles for comparison, this method provides calorimetric data on the gel-to-liquid-crystalline phase transition and its curvature effects and, in particular, the enthalpy change upon membrane deformation from a planar to a curved shape, which cannot be obtained by the conventional approach using differential scanning calorimetry. The results showed quantitatively that the increase in membrane curvature increases the enthalpy of 1,2-dimyristoyl-sn-glycero-3-phosphocholine membranes both below and above the phase-transition temperature, and that the effect is more significant for the former condition. The calorimetric data obtained are further discussed in relation to the elastic bending energy of the membranes and membrane-peptide interaction.

  20. Laser Calorimetry Spectroscopy for ppm-level Dissolved Gas Detection and Analysis

    Science.gov (United States)

    K. S., Nagapriya; Sinha, Shashank; R., Prashanth; Poonacha, Samhitha; Chaudhry, Gunaranjan; Bhattacharya, Anandaroop; Choudhury, Niloy; Mahalik, Saroj; Maity, Sandip

    2017-01-01

    In this paper we report a newly developed technique – laser calorimetry spectroscopy (LCS), which is a combination of laser absorption spectroscopy and calorimetry - for the detection of gases dissolved in liquids. The technique involves determination of concentration of a dissolved gas by irradiating the liquid with light of a wavelength where the gas absorbs, and measuring the temperature change caused by the absorbance. Conventionally, detection of dissolved gases with sufficient sensitivity and specificity was done by first extracting the gases from the liquid and then analyzing the gases using techniques such as gas chromatography. Using LCS, we have been able to detect ppm levels of dissolved gases without extracting them from the liquid. In this paper, we show the detection of dissolved acetylene in transformer oil in the mid infrared (MIR) wavelength (3021 nm) region. PMID:28218304

  1. 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.

  2. Revisiting the streptavidin-biotin binding by using an aptamer and displacement isothermal calorimetry titration.

    Science.gov (United States)

    Kuo, Tai-Chih; Tsai, Ching-Wei; Lee, Peng-Chen; Chen, Wen-Yih

    2015-03-01

    The association constant of a well-known streptavidin-biotin binding has only been inferred from separately measured kinetic parameters. In a single experiment, we obtained Ka 1 × 10(12)  M(-1) by using a streptavidin-binding aptamer and ligand-displacement isothermal titration calorimetry. This study explores the challenges of determining thermodynamic parameters and the derived equilibrium binding affinity of tight ligand-receptor binding.

  3. Investigation of used Conveyor Belts by the Differential Scanning Calorimetry Analysis

    Directory of Open Access Journals (Sweden)

    Lucia Knapcikova,

    2016-02-01

    Full Text Available In this paper is presented the use of differential scanning calorimetry analysis of the used conveyor belts. This method has been specifically tested on the individual components contained in the used conveyor belts esp. rubber pellets, cord and fabric. The result of the analysis is the determination of Tg temperature and melting temperatures (Tm by the components.Weanalyzed used conveyor belts and after this analysis it was determined components and their application to the industry

  4. 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.

  5. 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)...

  6. An investigation of the hydrogen desorption from Nd{sub 2}Fe{sub 17}H{sub x} and Dy{sub 2}Fe{sub 17}H{sub x} compounds by differential scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Cuevas, F. [ICMPE/CNRS-UPEC, UMR 7182, 2-8, rue Henri Dunant 94320, Thiais (France); Isnard, O., E-mail: olivier.isnard@grenoble.cnrs.fr [Institut Néel du CNRS et Université Joseph Fourier, BP 166 X, 38042 Grenoble cedex 9 (France); Villeroy, B. [ICMPE/CNRS-UPEC, UMR 7182, 2-8, rue Henri Dunant 94320, Thiais (France)

    2013-06-10

    Highlights: • We investigate the hydrogen desorption from R{sub 2}Fe{sub 17}H{sub x} (R = Nd and Dy) compounds. • The heat of hydrogen desorption is 29.2 ± 0.8 kJ mol H{sup −1} for both R{sub 2}Fe{sub 17}H{sub x} family compounds. • Hydrogen desorption activation energies have been determined from DSC. • Thermodynamical data are analysed for both heavy (Dy) and light (Nd) rare earth elements in the light of the precise knowledge of the crystal structure. - Abstract: Hydrogen desorption from R{sub 2}Fe{sub 17}H{sub x} (R = Nd and Dy) compounds with x ≤ 5 has been studied using differential scanning calorimetry (DSC). Overall hydrogen binding energies are very similar in both systems regardless their different crystal structures. The heat of hydrogen desorption is 29.2 ± 0.8 kJ mol H{sup −1} for both R{sub 2}Fe{sub 17}H{sub x} family compounds. Desorption activation energies are also very close: 78 ± 8 kJ and 79 ± 4 kJ mol H{sup −1} for Nd and Dy-containing compounds, respectively. The rare earth nature modifies however the local interaction between hydrogen and the intermetallic compound. For Nd, H-atoms occupy two non-equivalent and well-defined energy sites whereas a unique energy site with a broad energy distribution is detected for Dy. This peculiar behavior is discussed in terms of the different structural properties of the light (Nd) and heavy (Dy) rare-earth R{sub 2}Fe{sub 17} compounds.

  7. Picosecond calorimetry

    DEFF Research Database (Denmark)

    Georgiou, Panayiotis; Vincent, Jonathan; Andersson, Magnus

    2006-01-01

    to rapidly heat liquid C H2 Cl2 using UV pulses of 100 fs duration. A significant x-ray diffraction signal is visible prior to the onset of thermal expansion, which characterizes a highly compressed superheated liquid. Liquid C H2 Cl2 then expands as a shock wave propagates through the sample...

  8. STAR Calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, W W, E-mail: jacobsw@indiana.ed [Indiana University Cyclotron Facility and Department of Physics, 2401 Milo B. Sampson Lane, Bloomington IN 47408 (United States)

    2009-04-01

    The main STAR calorimeters comprise a full Barrel EMC and single Endcap EMC plus a Forward Meson Spectrometer. Together they give a nearly complete coverage over the range -1 < pseudorapidity < 4 and provide EM readout and triggering that help drive STAR physics capabilities. Their description, status, performance and operations (and a few physics anecdotes) are briefly presented and discussed.

  9. Percent relative cumulative frequency analysis in indirect calorimetry: application to studies of transgenic mice.

    Science.gov (United States)

    Riachi, Marc; Himms-Hagen, Jean; Harper, Mary-Ellen

    2004-12-01

    Indirect calorimetry is commonly used in research and clinical settings to assess characteristics of energy expenditure. Respiration chambers in indirect calorimetry allow measurements over long periods of time (e.g., hours to days) and thus the collection of large sets of data. Current methods of data analysis usually involve the extraction of only a selected small proportion of data, most commonly the data that reflects resting metabolic rate. Here, we describe a simple quantitative approach for the analysis of large data sets that is capable of detecting small differences in energy metabolism. We refer to it as the percent relative cumulative frequency (PRCF) approach and have applied it to the study of uncoupling protein-1 (UCP1) deficient and control mice. The approach involves sorting data in ascending order, calculating their cumulative frequency, and expressing the frequencies in the form of percentile curves. Results demonstrate the sensitivity of the PRCF approach for analyses of oxygen consumption (.VO2) as well as respiratory exchange ratio data. Statistical comparisons of PRCF curves are based on the 50th percentile values and curve slopes (H values). The application of the PRCF approach revealed that energy expenditure in UCP1-deficient mice housed and studied at room temperature (24 degrees C) is on average 10% lower (p calorimetry is increasingly used, and the PRCF approach provides a novel and powerful means for data analysis.

  10. Reading and listening to music increase resting energy expenditure during an indirect calorimetry test.

    Science.gov (United States)

    Snell, Blaire; Fullmer, Susan; Eggett, Dennis L

    2014-12-01

    Indirect calorimetry is often done early in the morning in a fasting state, with the subject unshowered and abstained from caffeine or other stimulants. Subjects often fall asleep, resulting in measurement of a sleeping metabolic rate rather than a resting metabolic rate. The objective of this study was to determine whether listening to self-selected relaxing music or reading an electronic device or magazine affects resting energy expenditure (REE) during measurement in healthy adults. A randomized trial comparing three different conditions (ie, resting, reading, and listening to music) was performed. Sixty-five subjects (36 female and 29 male) were used in final data analysis. Inclusion criteria included healthy subjects between the ages of 18 and 50 years with a stable weight. Exclusion criteria included pregnant or lactating women or use of medications known to affect metabolism. Results showed that reading either a magazine or an electronic device significantly increased REE by 102.7 kcal/day when compared with resting (Pmusic increased REE by 27.6 kcal/day compared with rest (P=0.0072). Based on our results, we recommend subjects refrain from reading a magazine or electronic device during an indirect calorimetry test. Whether or not the smaller difference found while listening to music is practically significant would be a decision for the indirect calorimetry test administrator.

  11. Numerical and Experimental Characterizations of Damping Properties of SMAs Composite for Vibration Control Systems

    Science.gov (United States)

    Biffi, Carlo Alberto; Bassani, P.; Tuissi, A.; Carnevale, M.; Lecis, N.; LoConte, A.; Previtali, B.

    2012-12-01

    Shape memory alloys (SMAs) are very interesting smart materials not only for their shape memory and superelastic effects but also because of their significant intrinsic damping capacity. The latter is exhibited upon martensitic transformations and especially in martensitic state. The combination of these SMA properties with the mechanical and the lightweight of fiberglass-reinforced polymer (FGRP) is a promising solution for manufacturing of innovative composites for vibration suppression in structural applications. CuZnAl sheets, after laser patterning, were embedded in a laminated composite between a thick FGRP core and two thin outer layers with the aim of maximizing the damping capacity of the beam for passive vibration suppression. The selected SMA Cu66Zn24Al10 at.% was prepared by vacuum induction melting; the ingot was subsequently hot-and-cold rolled down to 0.2 mm thickness tape. The choice of a copper alloy is related to some advantages in comparison with NiTiCu SMA alloys, which was tested for the similar presented application in a previous study: lower cost, higher storage modulus and consequently higher damping properties in martensitic state. The patterning of the SMA sheets was performed by means of a pulsed fiber laser. After the laser processing, the SMA sheets were heat treated to obtain the desired martensitic state at room temperature. The transformation temperatures were measured by differential scanning calorimetry (DSC). The damping properties were determined, at room temperature, on full-scale sheet, using a universal testing machine (MTS), with cyclic tensile tests at different deformation amplitudes. Damping properties were also determined as a function of the temperature on miniature samples with a dynamical mechanical analyzer (DMA). Numerical modeling of the laminated composite, done with finite element method analysis and modal strain energy approaches, was performed to estimate the corresponding total damping capacity and then

  12. X-linked dystonia parkinsonism syndrome (XDP, lubag): disease-specific sequence change DSC3 in TAF1/DYT3 affects genes in vesicular transport and dopamine metabolism.

    Science.gov (United States)

    Herzfeld, Thilo; Nolte, Dagmar; Grznarova, Maria; Hofmann, Andrea; Schultze, Joachim L; Müller, Ulrich

    2013-03-01

    X-chromosomal dystonia parkinsonism syndrome (XDP, 'lubag') is associated with sequence changes within the TAF1/DYT3 multiple transcript system. Although most sequence changes are intronic, one, disease-specific single-nucleotide change 3 (DSC3), is located within an exon (d4). Transcribed exon d4 occurs as part of multiple splice variants. These variants include exons d3 and d4 spliced to exons of TAF1, and an independent transcript composed of exons d2-d4. Location of DSC3 in exon d4 and utilization of this exon in multiple splice variants suggest an important role of DSC3 in the XDP pathogenesis. To test this hypothesis, we transfected neuroblastoma cells with four expression constructs, including exons d2-d4 [d2-d4/wild-type (wt) and d2-d4/DSC3] and d3-d4 (d3-d4/wt and d3-d4/DSC3). Expression profiling revealed a dramatic effect of DSC3 on overall gene expression. Three hundred and sixty-two genes differed between cells containing d2-d4/wt and d2-d4/DSC3. Annotation clustering revealed enrichment of genes related to vesicular transport, dopamine metabolism, synapse function, Ca(2+) metabolism and oxidative stress. Two hundred and eleven genes were differentially expressed in d3-d4/wt versus d3-d4/DSC3. Annotation clustering highlighted genes in signal transduction and cell-cell interaction. The data show an important role of physiologically occurring transcript d2-d4 in normal brain function. Interference with this role by DSC3 is a likely pathological mechanism in XDP. Disturbance of dopamine function and of Ca(2+) metabolism can explain abnormal movement; loss of protection against reactive oxygen species may account for the neurodegenerative changes in XDP. Although d3-d4 also affect genes potentially related to neurodegenerative processes, their physiologic role as splice variants of TAF1 awaits further exploration.

  13. Azide derivatized anticancer agents of Vitamin K 3: X-ray structural, DSC, resonance spectral and API studies

    Science.gov (United States)

    Badave, Kirti; Patil, Yogesh; Gonnade, Rajesh; Srinivas, Darbha; Dasgupta, Rajan; Khan, Ayesha; Rane, Sandhya

    2011-12-01

    Compound 1 [1-imino (acetyl hydrazino)-Vitamin K 3], displays valence tautomerically related electronic isomers as Form I and Form II. Form I exhibits 2D packing fragment with 1D ribbon chains of N-H⋯O hydrogen bonds and shows EPR silent features. While Form II is EPR active and exhibits biradical nature with double quantum transitions at g = 2.0040. 1H NMR of compound 2, [1-imino (hydrazino carboxylate)-Vitamin K 3] and Form II exhibit π delocalization via resonance assisted H-bonding [RAHB] effect compared to Form I. Molecular interactions in Form I and II are visualized by DSC. The electronic structures of compounds 1 and 2 have been correlated to their API values by measuring anticancer activities, mitochondrial potentials and DNA shearing patterns. Form II and compound 2 indicate mitochondria mediated apoptosis (˜75% cell death) while Form I causes 35% cell death.

  14. 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

  15. Kinetics of thermolysis of lanthanum nitrate with hexamethylenetetramine: Crystal structure, TG-DSC, impact and friction sensitivity studies, Part-96

    Science.gov (United States)

    Nibha; Baranwal, B. P.; Singh, Gurdip; Singh, C. P.; Daniliuc, Constantin G.; Soni, P. K.; Nath, Yogeshwar

    2014-11-01

    The development of high energetic materials includes process ability and the ability to attain insensitive munitions (IM). This paper investigates the preparation of lanthanum metal nitrate complex of hexamethylenetetramine in water at room temperature. This complex of molecular formulae [La (NO3)2(H2O)6] (2HMTA) (NO3-) (H2O) was characterized by X-ray crystallography. Thermal decomposition was investigated using TG, TG-DSC and ignition delay measurements. Kinetic analysis of isothermal TG data has been investigated using model fitting methods as well as model free isoconversional methods. The sensitivity measurements towards mechanical destructive stimuli such as impact and friction were carried out and the complex was found to be insensitive. In order to identify the end product of thermolysis, X-ray diffraction patterns of end product was carried out which proves the formation of La2O3.

  16. Regional and voxel-wise comparisons of blood flow measurements between dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) and arterial spin labeling (ASL) in brain tumors.

    Science.gov (United States)

    White, Carissa M; Pope, Whitney B; Zaw, Taryar; Qiao, Joe; Naeini, Kourosh M; Lai, Albert; Nghiemphu, Phioanh L; Wang, J J; Cloughesy, Timothy F; Ellingson, Benjamin M

    2014-01-01

    The objective of the current study was to evaluate the regional and voxel-wise correlation between dynamic susceptibility contrast (DSC) and arterial spin labeling (ASL) perfusion magnetic resonance imaging (MRI) measurement of cerebral blood flow (CBF) in patients with brain tumors. Thirty patients with histologically verified brain tumors were evaluated in the current study. DSC-MRI was performed by first using a preload dose of gadolinium contrast, then collecting a dynamic image acquisition during a bolus of contrast, followed by posthoc contrast agent leakage correction. Pseudocontinuous ASL was collected using 30 pairs of tag and control acquisition using a 3-dimensional gradient-echo spin-echo (GRASE) acquisition. All images were registered to a high-resolution anatomical atlas. Average CBF measurements within regions of contrast-enhancement and T2 hyperintensity were evaluated between the two modalities. Additionally, voxel-wise correlation between CBF measurements obtained with DSC and ASL were assessed. Results demonstrated a positive linear correlation between DSC and ASL measurements of CBF when regional average values were compared; however, a statistically significant voxel-wise correlation was only observed in around 30-40% of patients. These results suggest DSC and ASL may provide regionally similar, but spatially different measurements of CBF.

  17. Inclusion complexes of cypermethrin and permethrin with monochlorotriazinyl-beta-cyclodextrin: a combined spectroscopy, TG/DSC and DFT study.

    Science.gov (United States)

    Yao, Qi; You, Bin; Zhou, Shuli; Chen, Meng; Wang, Yujiao; Li, Wei

    2014-01-01

    The suitable size hydrophobic cavity and monochlorotriazinyl group as a reactive anchor make MCT-β-CD to be widely used in fabric finishing. In this paper, the inclusion complexes of monochlorotriazinyl-beta-cyclodextrin (MCT-β-CD) with cypermethrin (CYPERM) and permethrin (PERM) are synthesized and analyzed by TG/DSC, FT-IR and Raman spectroscopy. TG/DSC reveals that the decomposed temperatures of inclusion complexes are lower by 25-30 °C than that of physical mixtures. DFT calculations in conjunction with FT-IR and Raman spectral analyses are used to study the structures of MCT-β-CD and their inclusion complexes. Four isomers of trisubstituted MCT-β-CD are designed and DFT calculations reveal that 1,3,5-trisubstituted MCT-β-CD has the lowest energy and can be considered as main component of MCT-β-CD. The ground-state geometries, vibrational wavenumbers, IR and Raman intensities of MCT-β-CD and their inclusion complexes were calculated at B3LYP/6-31G (d) level of theory. Upon examining the optimized geometry of inclusion complex, we find that the CYPERM and PERM are inserted into the toroid of MCT-β-CD from the larger opening. The band at 1646 cm(-1) in IR and at 1668 cm(-1) in Raman spectrum reveals that monochloroazinyl group of MCT-β-CD exists in ketone form but not in anion form. The noticeable IR and Raman shift of phenyl reveals that these two benzene rings of CYPERM and PERM stays inside the cavity of MCT-β-CD and has weak interaction with MCT-β-CD. This spectroscopy conclusion is consistent with theoretical predicted structure.

  18. Assessment of lifetime resolution limits in time-resolved photoacoustic calorimetry vs. transducer frequencies: setting the stage for picosecond resolution.

    Science.gov (United States)

    Schaberle, Fábio A; Rego Filho, Francisco de Assis M G; Reis, Luís A; Arnaut, Luis G

    2016-02-01

    Time-resolved photoacoustic calorimetry (PAC) gives access to lifetimes and energy fractions of reaction intermediates by deconvolution of the photoacoustic wave of a sample (E-wave) with that of the instrumental response (T-wave). The ability to discriminate between short lifetimes increases with transducer frequencies employed to detect the PAC waves. We investigate the lifetime resolution limits of PAC as a function of the transducer frequencies using the instrumental response obtained with the photoacoustic reference 2-hydroxybenzophenone in toluene or acetonitrile. The instrumental response was obtained for a set of transducers with central frequencies ranging from 0.5 MHz up to 225 MHz. The simulated dependence of the lifetime resolution with the transducer frequencies was anchored on experimental data obtained for the singlet state of naphthalene with a 2.25 MHz transducer. The shortest lifetime resolved with the 2.25 MHz transducer was 19 ns and our modelling of the transducer responses indicates that sub-nanosecond lifetimes of photoacoustic transients can be resolved with transducers of central frequencies above 100 MHz.

  19. 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.

  20. DSC studies of gamma irradiation influence on gelatinisation and amylose-lipid complex transition occurring in wheat starch

    Science.gov (United States)

    Cieśla, K.; Eliasson, A.-C.

    2003-12-01

    Differential scanning calorimetry studies are presented dealing with the influence of gamma irradiation (carried out in the solid state) on the structure of amylose-lipid complex in wheat starch . Suspensions of the control and the wheat starch irradiated with a 30 kGy gamma rays (characterised by starch-to-water ratio of 1:1 and ca. 1:4) were examined during several courses of heating and cooling at rates of 2.5 and 10°C min -1. Differences were observed between enthalpy and temperature of gelatinisation and amylose-lipid complex transition as well as retrogradation taking place in the suspensions and gels of the control and the irradiated starch. The influence of the preceding heating and cooling on further transformations of the amylose-lipid complex differs for the control and the irradiated samples.