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Sample records for calorimetry dsc experiments

  1. Differential Scanning Calorimetry (DSC) for planetary surface exploration

    NASA Technical Reports Server (NTRS)

    Gooding, James L.; Ming, Douglas W.

    1993-01-01

    Differential Scanning Calorimetry (DSC) is the quantitative measurement of the enthalpic response of a material to a systematic change in temperature. In practice, the heat flow into or outward from a sample is measured as the sample is heated or cooled at a carefully controlled rate. DSC superficially resembles, but is not the same as differential thermal analysis (DTA), which is the measurement of temperature differences between a sample and reference material as the pair is heated or cooled. The fundamental properties measured by DSC are enthalpies and temperatures of phase transitions and constant-pressure heat capacities. Depending on instrument design and the nature of the sample, high-quality DSC analyses can be obtained on only a few milligrams of solid materials. DSC requires direct contact with the sample and generally degrades, if not destroys, the sample as a consequence of heating. In laboratory applications, it is common to subject the gaseous effluent from the DSC to analysis by a separate evolved-gas analyzer (EGA).

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

    ERIC Educational Resources Information Center

    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)

  3. Thermodynamic properties of diosgenin determined by oxygen-bomb calorimetry and DSC

    NASA Astrophysics Data System (ADS)

    Zhao, Ming-Rui; Wang, Hong-Jie; Wang, Shu-Yu; Yue, Xiao-Xin

    2014-12-01

    The combustion enthalpy of diosgenin was determined by oxygen-bomb calorimetry. The standard mole combustion enthalpy and the standard mole formation enthalpy have been calculated to be -16098.68 and -528.52 kJ mol-1, respectively. Fusion enthalpy and melting temperature for diosgenin were also measured to be -34.43 kJ mol-1 and 212.33°C, respectively, according to differential scanning calorimetry (DSC) data. These studies can provide useful thermodynamic data for this compound.

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

    PubMed

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

    2016-05-25

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

  5. Relaxation behaviour of D(-)-salicin as studied by Thermally Stimulated Depolarisation Currents (TSDC) and Differential Scanning Calorimetry (DSC).

    PubMed

    Diogo, Hermínio P; Pinto, Susana S; Moura Ramos, Joaquim J

    2008-06-24

    Thermally Stimulated Depolarisation Currents (TSDC) measurements on D(-)-salicin have been carried out in the temperature region from -165 degrees C up to 150 degrees C. The slow molecular mobility was characterised in the crystal and in the glassy state. The value of the steepness index or fragility (T(g)-normalized temperature dependence of the relaxation time) was obtained by Differential Scanning Calorimetry (DSC) from the analysis of the scanning rate dependency of T(g). The existence of an unknown polymorph of salicin is also reported. PMID:18417303

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

    NASA Astrophysics Data System (ADS)

    Bush, Ralph; Kiyota, Michelle; Kiyota, Catherine

    2016-04-01

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

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

    NASA Astrophysics Data System (ADS)

    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.

  8. Use of Differential Scanning Calorimetry (DSC) in the Characterization of EPDM/PP Blends

    NASA Astrophysics Data System (ADS)

    Stelescu, Maria Daniela; Airinei, Anton; Grigoras, Cristian; Niculescu-Aron, Ileana-Gabriela

    2010-12-01

    New polyolefinic thermoplastic elastomers based on the ethylene-propylene-diene monomer (EPDM) and polypropylene (PP) containing an EPDM elastomer of the last generation (Nordel NDR 47130), obtained by polymerization in the gaseous phase with metallocene catalysis, were prepared and characterized. The melting and crystallization behavior of these blends was investigated by differential scanning calorimetry. It is observed that the melting temperature, crystallization temperature, and crystallinity degree increase with an increase of PP loading. The influence of the blend composition on the physico-mechanical characteristics was discussed using statistical processing of the experimental data. Two compatibilizing procedures were utilized to improve the physico-mechanical characteristics of the samples: an addition method using different compatibilizing agents and dynamical vulcanization with three types of crosslinking systems. Significant improvements of the tensile strength and tear strength were noted by dynamic crosslinking, and the best results were obtained using a crosslinking system based on phenolic resin and tin chloride.

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

    PubMed

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

    2015-11-01

    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. PMID:26457879

  10. 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)

    SciTech Connect

    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.

  11. Characterization of Two Different Clay Materials by Thermogravimetry (TG), Differential Scanning Calorimetry (DSC), Dilatometry (DIL) and Mass Spectrometry (MS) - 12215

    SciTech Connect

    Post, Ekkehard; Henderson, Jack B.

    2012-07-01

    An illitic clay containing higher amounts of organic materials was investigated by dilatometry, thermogravimetry and differential scanning calorimetric. The evolved gases were studied during simultaneous TG-DSC (STA) and dilatometer measurements with simultaneous mass spectrometry in inert gas and oxidizing atmosphere. The dilatometer results were compared with the STA-MS results which confirmed and explained the reactions found during heating of the clay, like dehydration, dehydroxylation, shrinkage, sintering, quartz phase transition, combustion or pyrolysis of organics and the solid state reactions forming meta-kaolinite and mullite. The high amount of organic material effects in inert gas atmosphere most probably a reduction of the oxides which leads to a higher mass loss than in oxidizing atmosphere. Due to this reduction an additional CO{sub 2} emission at around 1000 deg. C was detected which did not occur in oxidizing atmosphere. Furthermore TG-MS results of a clay containing alkali nitrates show that during heating, in addition to water and CO{sub 2}, NO and NO{sub 2} are also evolved, leading to additional mass loss steps. These types of clays showed water loss starting around 100 deg. C or even earlier. This relative small mass loss affects only less shrinkage during the expansion of the sample. The dehydroxylation and the high crystalline quartz content result in considerable shrinkage and expansion of the clay. During the usual solid state reaction where the clay structure collapses, the remaining material finally shrinks down to a so-called clinker. With the help of MS the TG steps can be better interpreted as the evolved gases are identified. With the help of the MS it is possible to distinguish between CO{sub 2} and water (carbonate decomposition, oxidation of organics or dehydration/dehydroxylation). The MS also clearly shows that mass number 44 is found during the TG step of the illitic clay at about 900 deg. C in inert gas, which was interpreted

  12. Solution Calorimetry Experiments for Physical Chemistry.

    ERIC Educational Resources Information Center

    Raizen, Deborah A.; And Others

    1988-01-01

    Presents two experiments: the first one measures the heat of an exothermic reaction by the reduction of permanganate by the ferris ion; the second one measures the heat of an endothermic process, the mixing of ethanol and cyclohexane. Lists tables to aid in the use of the solution calorimeter. (MVL)

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

    PubMed Central

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

    2010-01-01

    This paper reviews the best-known differential scanning calorimetries (DSCs), such as conventional DSC, microelectromechanical systems-DSC, infrared-heated DSC, modulated-temperature DSC, gas flow-modulated DSC, parallel-nano DSC, pressure perturbation calorimetry, self-reference DSC, and high-performance DSC. Also, we describe here the most extensive applications of DSC in biology and nanoscience. PMID:21119929

  14. Simultaneous TG/DSC (thermogravimetry/differential scanning calorimetry) and TG/MS (thermogravimetry/mass spectrometry) analyses of polymeric and energetic materials

    SciTech Connect

    Whitaker, R B; Brown, C R; Chang, C; McDaniel, J A; Shell, T L

    1987-01-01

    The utility of simultaneous thermal analysis techniques, such as TG/DSC and TG/MS, has been demonstrated for both energetic and polymeric materials. TG/DSC can assist in elucidating reaction mechanisms and determining weight losses for endothermic transitions which precede decomposition of energetic materials. The endothermic and exothermic nature of decomposition processes can be defined by TG/DSC and the decomposition products identified by TG/MS.

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed

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

    2016-01-01

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

  17. Identifying Hydrated Salts Using Simultaneous Thermogravimetric Analysis and Differential Scanning Calorimetry

    ERIC Educational Resources Information Center

    Harris, Jerry D.; Rusch, Aaron W.

    2013-01-01

    simultaneous thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) to characterize colorless, hydrated salts with anhydrous melting points less than 1100 degrees C. The experiment could be used to supplement the lecture discussing gravimetric techniques. It is…

  18. Preparation To Minimize Buffer Mismatch in Isothermal Titration Calorimetry Experiments.

    PubMed

    Bian, Xuelin; Lockless, Steve W

    2016-05-17

    There is a growing need to study ligand binding to proteins in native or complex solution using isothermal titration calorimetry (ITC). For example, it is desirable to measure ligand binding to membrane proteins in more native lipid-like environments such as bicelles, where ligands can access both sides of the membrane in a homogeneous environment. A critical step to obtain high signal-to-noise is matching the reaction chamber solution to the ligand solution, typically through a final dialysis or gel filtration step. However, to obtain reproducible bicelles, the lipid concentrations must be carefully controlled which eliminates the use of dialysis that can disrupt these parameters. Here, we report and validate a rapid preparation ITC (RP-ITC) approach to measure ligand binding without the need for a dialysis step. This general approach is used to quantify ion binding to a K(+) channel embedded in bicelles and can be applied to complex, less defined systems. PMID:27092566

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

    NASA Technical Reports Server (NTRS)

    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.

  20. Review of calorimetry in Fermilab fixed-target experiments

    SciTech Connect

    Crisler, M.B.

    1995-04-01

    The fixed-target program at Fermilab comprises as many as thirteen simultaneous experiments in ten separate beamlines using beams of primary protons, pions, kaons, electrons, neutrinos, and muons. The fixed target beamlines were last in operation in the latter half of 1991, shutting down in 1992. The next fixed target run is scheduled for early 1996. This article describes some of the wide variety of calorimetric devices that were in use in the past run or to be used in the coming run. Special attention is devoted to the new devices currently under construction.

  1. The Enthalpy of Decomposition of Hydrogen Peroxide: A General Chemistry Calorimetry Experiment

    NASA Astrophysics Data System (ADS)

    Marzzacco, Charles J.

    1999-11-01

    A calorimetry experiment involving the catalytic decomposition of aqueous hydrogen peroxide is presented. The experiment is simple, inexpensive, and colorful. In its simplest form, it can be performed in less than one hour; therefore, it is quite suitable for high school labs, which often have time restrictions. The chemicals required are household or commercial 3% H2O2(aq) and 0.50 M Fe(NO3)3(aq). Styrofoam cup calorimeters and thermometers with a range from 20 to 50 oC are also required. Ideally, the thermometers should be precise to 0.01 oC. The temperature of the H2O2 solution is monitored before and after the Fe(NO3)3 catalyst is added. The addition of the catalyst results in a color change and the evolution of heat and bubbles of oxygen. At the conclusion of the reaction, the color of the reaction mixture returns to that of the original Fe(NO3)3 solution. The heat change for the reaction is determined from the temperature change, the specific heat of the solution, and the calorimeter constant. The experimental enthalpy change for the reaction is in excellent agreement with the literature value.

  2. Dynamic Calorimetry for Students

    ERIC Educational Resources Information Center

    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…

  3. Neutron monitoring and electrode calorimetry experiments in the HIP-1 Hot Ion Plasma

    NASA Technical Reports Server (NTRS)

    Reinmann, J. J.; Layman, R. W.

    1977-01-01

    Results are presented for two diagnostic procedures on HIP-1: neutron diagnostics to determine where neutrons originated within the plasma discharge chamber and electrode calorimetry to measure the steady-state power absorbed by the two anodes and cathodes. Results are also reported for a hot-ion plasma formed with a continuous-cathode rod, one that spans the full length of the test section, in place of the two hollow cathodes. The outboard neutron source strength increased relative to that at the midplane when (1) the cathode tips were moved farther outboard, (2) the anode diameters were increased, and (3) one of the anodes was removed. The distribution of neutron sources within the plasma discharge chamber was insensitive to the division of current between the two cathodes. For the continuous cathode, increasing the discharge current increased the midplane neutron source strength relative to the outboard source strength. Each cathode absorbed from 12 to 15 percent of the input power regardless of the division of current between the cathodes. The anodes absorbed from 20 to 40 percent of the input power. The division of power absorption between the anodes varied with plasma operating conditions and electrode placement.

  4. Quantum Calorimetry

    NASA Technical Reports Server (NTRS)

    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.

  5. Gelatinisation kinetics of corn and chickpea starches using DSC, RVA, and dynamic rheometry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The gelatinisation kinetics (non-isothermal) of corn and chickpea starches at different heating rates were calculated using differential scanning calorimetry (DSC), rapid visco analyser (RVA), and oscillatory dynamic rheometry. The data obtained from the DSC thermogram and the RVA profiles were fitt...

  6. Glass transition in polymers: Comparison of results from DSC, TMA, and TOA measurements

    SciTech Connect

    Wiedemann, H.G.; Widmann, G.; Bayer, G.

    1994-09-01

    The determination of the glass transition temperature, T{sub g}, of polymers by differential scanning calorimetry (DSC) and thermomechanical analysis (TMA) is sometimes problematic and rather subjective. This was shown previously in the ICTA certificate (distributed by NBS as GM-754) for the certified reference material polystyrene (PS). The not very good reproducibility of the measured value of the onset is due to a variety of instrumental and experimental parameters. This is true also for the determination of the glass transition by TMA measurements. The main reasons are temperature gradients caused by the relatively high sample mass required for DSC and by the limited heat transfer in TMA, respectively. Their own experiments which were carried out with polystyrene and with [poly(ethyleneterephthalate)] (PET) proved that a combination of DSC with TOA (thermo-optical analysis or hot stage microscopy under polarized light) can solve some of these problems. TOA is a nonsubjective method since the changes in birefringence and light transmittance during the glass transition which are visible under the microscope are measured with a photocell. TOA allows T{sub g} measurements of small samples (fraction of milligrams).

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

    PubMed

    Yang, Zhengrong; Brouillette, Christie G

    2016-01-01

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

  8. PURITY AND HEAT OF FUSION DATA FOR ENVIRONMENTAL STANDARDS AS DETERMINED BY DIFFERENTIAL SCANNING CALORIMETRY

    EPA Science Inventory

    Differential scanning calorimetry (DSC) has been applied to 273 environmental standards, including pesticides, herbicides and related compounds. embers of the following chemical classes were analyzed: rganophosphorus, organochlorine, phenol, triazine, uracil, phenoxy acid, urea, ...

  9. Determination of the solubility of crystalline low molar mass compounds in polymers by differential scanning calorimetry.

    PubMed

    Rager, Timo

    2014-06-01

    A mathematical equation has been derived to calculate the liquidus for a binary system consisting of an amorphous polymer and a crystalline low molar mass compound. The experimental input to this equation is an interaction enthalpy, which is derived from the variation of the melting enthalpy with composition in differential scanning calorimetry (DSC) experiments. The predictive power of the equation has been tested with mixtures of acetylsalicylic acid, carbamazepine, or intraconazole with poly(ethylene glycol) as well as mixtures of carbamazepine with poly(acrylic acid), poly(hydroxystyrene), or poly(vinylpyrrolidone). It has been confirmed that the evaluation of the melting enthalpy in DSC is a suitable method to identify the preferred solute-polymer combinations for thermodynamically stable molecular dispersions. PMID:24723307

  10. Deconvolution of complex differential scanning calorimetry profiles for protein transitions under kinetic control.

    PubMed

    Toledo-Núñez, Citlali; Vera-Robles, L Iraís; Arroyo-Maya, Izlia J; Hernández-Arana, Andrés

    2016-09-15

    A frequent outcome in differential scanning calorimetry (DSC) experiments carried out with large proteins is the irreversibility of the observed endothermic effects. In these cases, DSC profiles are analyzed according to methods developed for temperature-induced denaturation transitions occurring under kinetic control. In the one-step irreversible model (native → denatured) the characteristics of the observed single-peaked endotherm depend on the denaturation enthalpy and the temperature dependence of the reaction rate constant, k. Several procedures have been devised to obtain the parameters that determine the variation of k with temperature. Here, we have elaborated on one of these procedures in order to analyze more complex DSC profiles. Synthetic data for a heat capacity curve were generated according to a model with two sequential reactions; the temperature dependence of each of the two rate constants involved was determined, according to the Eyring's equation, by two fixed parameters. It was then shown that our deconvolution procedure, by making use of heat capacity data alone, permits to extract the parameter values that were initially used. Finally, experimental DSC traces showing two and three maxima were analyzed and reproduced with relative success according to two- and four-step sequential models. PMID:27402175

  11. On the Development of Thermally Stable Semi-IPNs of PVA and PAN using IR, DSC and XRD Studies

    NASA Astrophysics Data System (ADS)

    Deshpande, Deepti S.; Bajpai, R.; Bajpai, A. K.

    2011-07-01

    A novel biopolymer based Semi-IPN of polyvinyl alcohol (PVA) and polycrylonitrile (PAN) were synthesized in various proportions by redox polymerization and analyzed thermally by differential scanning calorimetry (DSC). DSC thermograms shows good thermal stability, as a result of incorporation of acrylonitrile as the second network. The structural and morphological study of these semi-IPNs by FTIR and XRD technique, respectively, were correlated. The approach seems to be beneficial for various biomedical applications.

  12. Scintillator plate calorimetry

    SciTech Connect

    Price, L.E.

    1990-01-01

    Calorimetry using scintillator plates or tiles alternated with sheets of (usually heavy) passive absorber has been proven over multiple generations of collider detectors. Recent detectors including UA1, CDF, and ZEUS have shown good results from such calorimeters. The advantages offered by scintillator calorimetry for the SSC environment, in particular, are speed (<10 nsec), excellent energy resolution, low noise, and ease of achieving compensation and hence linearity. On the negative side of the ledger can be placed the historical sensitivity of plastic scintillators to radiation damage, the possibility of nonuniform response because of light attenuation, and the presence of cracks for light collection via wavelength shifting plastic (traditionally in sheet form). This approach to calorimetry is being investigated for SSC use by a collaboration of Ames Laboratory/Iowa State University, Argonne National Laboratory, Bicron Corporation, Florida State University, Louisiana State University, University of Mississippi, Oak Ridge National Laboratory, Virginia Polytechnic Institute and State University, Westinghouse Electric Corporation, and University of Wisconsin.

  13. Calorimetry for the SSC

    SciTech Connect

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

    1984-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

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

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed Central

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

    2016-01-01

    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. PMID:27319782

  17. Scintillator materials for calorimetry

    SciTech Connect

    Weber, M.J.

    1994-09-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

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

    NASA Astrophysics Data System (ADS)

    Arnold, Michael Colin

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

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

    SciTech Connect

    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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  3. Isothermal titration calorimetry of RNA.

    PubMed

    Salim, Nilshad N; Feig, Andrew L

    2009-03-01

    Isothermal titration calorimetry (ITC) is a fast and robust method to study the physical basis of molecular interactions. A single well-designed experiment can provide complete thermodynamic characterization of a binding reaction, including K(a), DeltaG, DeltaH, DeltaS and reaction stoichiometry (n). Repeating the experiment at different temperatures allows determination of the heat capacity change (DeltaC(P)) of the interaction. Modern calorimeters are sensitive enough to probe even weak biological interactions making ITC a very popular method among biochemists. Although ITC has been applied to protein studies for many years, it is becoming widely applicable in RNA biochemistry as well, especially in studies which involve RNA folding and RNA interactions with small molecules, proteins and with other RNAs. This review focuses on best practices for planning, designing and executing effective ITC experiments when one or more of the reactants is an RNA. PMID:18835447

  4. Probing perturbation of bovine lung surfactant extracts by albumin using DSC and 2H-NMR.

    PubMed

    Nag, Kaushik; Keough, Kevin M W; Morrow, Michael R

    2006-05-15

    Lung surfactant (LS), a lipid-protein mixture, forms films at the lung air-water interface and prevents alveolar collapse at end expiration. In lung disease and injury, the surface activity of LS is inhibited by leakage of serum proteins such as albumin into the alveolar hypophase. Multilamellar vesicular dispersions of a clinically used replacement, bovine lipid extract surfactant (BLES), to which (2% by weight) chain-perdeuterated dipalmitoylphosphatidycholine (DPPG mixtures-d(62)) had been added, were studied using deuterium-NMR spectroscopy ((2)H-NMR) and differential scanning calorimetry (DSC). DSC scans of BLES showed a broad gel to liquid-crystalline phase transition between 10-35 degrees C, with a temperature of maximum heat flow (T(max)) around 27 degrees C. Incorporation of the DPPC-d(62) into BLES-reconstituted vesicles did not alter the T(max) or the transition range as observed by DSC or the hydrocarbon stretching modes of the lipids observed using infrared spectroscopy. Transition enthalpy change and (2)H-NMR order parameter profiles were not significantly altered by addition of calcium and cholesterol to BLES. (2)H-NMR spectra of the DPPC-d(62) probes in these samples were characteristic of a single average lipid environment at all temperatures. This suggested either continuous ordering of the bilayer through the transition during cooling or averaging of the DPPC-d(62) environment by rapid diffusion between small domains on a short timescale relative to that characteristic of the (2)H-NMR experiment. Addition of 10% by weight of soluble bovine serum albumin (1:0.1, BLES/albumin, dry wt/wt) broadened the transition slightly and resulted in the superposition of (2)H-NMR spectral features characteristic of coexisting fluid and ordered phases. This suggests the persistence of phase-separated domains throughout the transition regime (5-35 degrees C) of BLES with albumin. The study suggests albumin can cause segregation of protein bound-lipid domains in

  5. Extruded scintillator for the calorimetry applications

    SciTech Connect

    Dyshkant, A.; Rykalin, V.; Pla-Dalmau, A.; Beznosko, D.; /SUNY, Stony Brook

    2006-08-01

    An extrusion line has been installed and successfully operated at FNAL (Fermi National Accelerator Laboratory) in collaboration with NICADD (Northern Illinois Center for Accelerator and Detector Development). This new Facility will serve to further develop and improve extruded plastic scintillator. Recently progress has been made in producing co-extruded plastic scintillator, thus increasing the potential HEP applications of this Facility. The current R&D work with extruded and co-extruded plastic scintillator for a potential ALICE upgrade, the ILC calorimetry program and the MINERvA experiment show the attractiveness of the chosen strategy for future experiments and calorimetry. We extensively discuss extruded and co-extruded plastic scintillator in calorimetry in synergy with new Solid State Photomultipliers. The characteristics of extruded and co-extruded plastic scintillator will be presented here as well as results with non-traditional photo read-out.

  6. Extruded scintillator for the Calorimetry applications

    SciTech Connect

    Dyshkant, A.; Rykalin, V.; Pla-Dalmau, A.; Beznosko, D.

    2006-10-27

    An extrusion line has been installed and successfully operated at FNAL (Fermi National Accelerator Laboratory) in collaboration with NICADD (Northern Illinois Center for Accelerator and Detector Development). This new Facility will serve to further develop and improve extruded plastic scintillator. Recently progress has been made in producing co-extruded plastic scintillator, thus increasing the potential HEP applications of this Facility. The current R and D work with extruded and co-extruded plastic scintillator for a potential ALICE upgrade, the ILC calorimetry program and the MINERvA experiment show the attractiveness of the chosen strategy for future experiments and calorimetry. We extensively discuss extruded and co-extruded plastic scintillator in calorimetry in synergy with new Solid State Photomultipliers. The characteristics of extruded and co-extruded plastic scintillator will be presented here as well as results with non-traditional photo read-out.

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

    PubMed Central

    Chiu, Michael H.; Prenner, Elmar J.

    2011-01-01

    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. PMID:21430954

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

    NASA Technical Reports Server (NTRS)

    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.

  9. Evidence of [eta]' or ordered zone formation in aluminum alloy 7075 from differential scanning calorimetry. [Aluminium alloy 7075

    SciTech Connect

    Bartges, C.W. )

    1993-05-01

    The development of high strength levels in Al-Mg-Zn-(Cu) alloys is dependent on the decomposition of the supersaturated solid solution ([alpha][sub ss]). The equilibrium phase, [eta], and the transition phase, [eta][prime], have compositions Mg(Zn, Al, Cu)[sub 2] and the GP Zones are solute rich clusters. Several authors have presented evidence that there is another precipitate which forms between the GP Zones and [eta][prime], though there is some controversy whether it is crystallographically distinct from the matrix, [eta][prime], or an ordered GP Zone. Regardless of their structure, these particles are seldom observed and are not usually considered in the decomposition of these alloys. Most of the previous observations of these particles have been the result of involved transmission electron microscopic and X-ray scattering experiments. This report shows they may also be detected using differential scanning calorimetry (DSC). Also significant is the fact that the particles were observed in AA 7075, an important commercial alloy. Lloyd and Chaturvedi also saw indications of [eta][prime] or ordered zones using DSC, but the results reported herein are different in several important respects. DSC traces of alloys aged for various times at room temperature and 121 C have shown there is at least one phase which can form during the decomposition of aluminum alloy 7075 that is not usually stated in the decomposition reaction. The results of previous studies suggest they may be ordered GP Zones or [eta][prime].

  10. Thermal Properties of Trogamid by Conventional and Fast Scanning Calorimetry

    NASA Astrophysics Data System (ADS)

    Cebe, Peggy; Merfeld, John; Mao, Bin; Wurm, Andreas; Zhuravlev, Evgeny; Schick, Christoph

    We use conventional slow scan rate differential scanning calorimetry, and fast scanning chip-based calorimetry (FSC), to investigate the crystallization and melting behavior of Trogamid, a chemical relative of nylon. Fundamental thermal properties of Trogamid were studied, including the melt crystallization kinetics, heat of fusion, and the solid and liquid state heat capacities. Using slow scan DSC (at 5 K/min), Trogamid displays a glass transition relaxation process at ~133 C, melting endotherm peak at 250 C, and is stable upon repeated heating to 310 C. When using slow scan DSC, the isothermal melt crystallization temperatures were restricted to 225 C or above. Trogamid crystallizes rapidly from the melt and conventional calorimetry is unable to cool sufficiently fast to prevent nucleation and crystal growth prior to stabilization at lower crystallization temperatures. Using FSC we were able to cool nano-gram sizes samples at 2000 K/s to investigate a much lower range of melt crystallization temperatures, from 205-225 C. The experimental protocol for performing FSC on semicrystalline polymers to obtain liquid state heat capacity data will be presented. National Science Foundation, Polymers Program DMR-1206010; DAAD; Tufts Faculty Supported Leave.

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

    PubMed

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

    2008-09-01

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

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

    PubMed

    Lin, Shan-Yang; Lin, Chih-Cheng

    2016-01-01

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

  13. Measuring the glass transition temperature of EPDM roofing materials: Comparison of DMA, TMA, and DSC techniques

    SciTech Connect

    Paroli, R.M.; Penn, J.

    1994-09-01

    Two ethylene-propylene-diene monomer (EPDM) roofing membranes were aged at 100 C for 7 and 28 days. The T{sub g} of these membranes was then determined by dynamic mechanical analysis (DMA), thermomechanical analysis (TMA), and differential scanning calorimetry (DSC) and the results compared. It was found that: (1) T{sub g} data can be obtained easily using the DMA and TMA techniques. The DSC method requires greater care due to the broad step change in the baseline which is associated with heavily plasticized materials. (2) The closest correspondence between techniques was for TMA and DSC (half-height). The latter, within experimental error, yielded the same glass transition temperature before and after heat-aging. (3) The peak maxima associated with tan{delta} and E{double_prime} measurements should be cited with T{sub g} values as significant differences can exist. (4) The T{sub g}(E{double_prime}) values were closer to the T{sub g}(TMA) and T{sub g}(DSC) data than were the T{sub g}(tan{delta}) values. Data obtained at 1 Hz (or possibly less) should be used when making comparisons based on various techniques. An assessment of T{sub g} values indicated that EPDM 112 roofing membrane is more stable than the EPDM 111 membrane. The T{sub g} for EPDM 112 did not change significantly with heat-aging for 28 days at 130 C.

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

    NASA Technical Reports Server (NTRS)

    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.

  15. DSC And Raman Studies Of Diglycine-perchlorate (DGPCl) Doped TGS

    NASA Astrophysics Data System (ADS)

    Panicker, Lata; Sakuntala, T.

    2010-12-01

    Single crystals of diglycine perchlorate (DGPCl) doped triglycine sulphate(TGS) has been obtained and studied using differential scanning calorimetry and Raman. DSC and Raman analysis shows that the thermal and vibrational property of TGS is affected by DGPCl. However, the basic crystal structure of TGS is not perturbed significantly by the dopent. A small fraction of SO42- anions seems to be replaced by ClO4- in the TGS crystal structure. The presence of ClO4- anions in TGS crystals can affect the ferroelectric properties of TGS.

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

    PubMed

    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. Differential scanning calorimetry in determining kinetics parameter of Si oxidation

    NASA Astrophysics Data System (ADS)

    Faruque, Sk. Abdul Kader Md.; Chakraborty, Supratic

    2016-05-01

    Differential scanning calorimetry (DSC) technique is employed here to study the oxidation of silicon by solid-gas reaction at a constant heating rate. The diffusion coefficient of oxygen into silicon at 900 °C is estimated from the kinetic equation of 1-dimensional diffusion controlled growth. The diffusion coefficient, D estimated as 4.5 × 10-5 exp (1.01ev/κBT) m2/s, as is in well agreement with the standard value available in literature.

  18. Oxidation behaviour of mechanically activated Mn{sub 3}O{sub 4} by TGA/DSC/XRPD

    SciTech Connect

    Berbenni, V.; Marini, A

    2003-11-26

    The effect of high energy milling on the solid-state reactions taking place in Mn{sub 3}O{sub 4} has been studied. Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) have been employed to study the solid-state reaction occurring under air in the temperature range between room temperature (rt) and 1100 deg. C. X-ray Powder Diffractometry (XRPD) has been used to ascertain the chemical nature of the transformations brought into evidence by thermo-analysis.

  19. Estimation of the fragility index of indomethacin by DSC using the heating and cooling rate dependency of the glass transition.

    PubMed

    Ramos, Joaquim J Moura; Taveira-Marques, Raquel; Diogo, Hermínio P

    2004-06-01

    In this study we have investigated the features of the glass transition relaxation of indomethacin using Differential Scanning Calorimetry (DSC). The purpose of this work is to provide an estimation of the activation energy at the glass transition temperature, as well as of the fragility index, of amorphous indomethacin from DSC data. To do so, the glass transition temperature region of amorphous indomethacin was characterized in both cooling and heating regimes. The activation energy for structural relaxation (directly related to glass fragility) was estimated from the heating and cooling rate dependence of the location of the DSC profile of the glass transition. The obtained results were similar in the heating and in the cooling modes. The results on the fragility index of indomethacin obtained in the present study, m = 60 in the cooling mode and m = 56 in the heating mode, are compared with other values previously published in the literature. PMID:15124208

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

    PubMed

    You, Mei-Li

    2016-01-01

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

  1. A comparison of the DSC measurements of shape memory alloys and the material's thermal characteristics in a large scale actuator

    NASA Astrophysics Data System (ADS)

    Mabe, James H.; Yu, Chin-Jye; Rosenzweig, Ed

    2006-03-01

    An accurate measure of a Shape Memory Alloy's (SMA) transition temperatures is necessary for the development of successful SMA actuator designs. Differential Scanning Calorimetry (DSC) is used to obtain SMA transition temperatures associated with changes in alloy formulations, fabrication processes, and forming methods, and to predict an SMA's thermal characteristics when designed into an actuator. However there is little data directly correlating a material's DSC results with its performance in an actuator configuration, particularly for large-scale actuators producing high force and large displacements. In this paper the authors compare the DSC results of several NiTinol samples with the thermal performance of the same material in a rotary actuator. Data are presented for NiTinol torque tubes 14cm (5.5 in) long by 1 cm (0.4 in) in diameter. The tubes were tested over a range of loads exceeding 17 N*m (150 in-lbs) of torque, with angular displacements of more than 60 degrees, and for durations exceeding 3,500 thermal cycles. Data from various NiTinol suppliers, levels of cold work, and a range of aging temperatures is presented. The DSC data is directly compared to the strain vs. temperature hysteresis curves of the same material under various loads; both before and after extended cycling. The value of the DSC measurements as a predictor of a material's thermal characteristics in an actuator configuration is assessed.

  2. CALORIMETRY OF TRU WASTE MATERIALS

    SciTech Connect

    C. RUDY; ET AL

    2000-08-01

    Calorimetry has been used for accountability measurements of nuclear material in the US. Its high accuracy, insensitivity to matrix effects, and measurement traceability to National Institute of Standards and Technology have made it the primary accountability assay technique for plutonium (Pu) and tritium in the Department of Energy complex. A measurement of Pu isotopic composition by gamma-ray spectroscopy is required to transform the calorimeter measurement into grams Pu. The favorable calorimetry attributes allow it to be used for verification measurements, for production of secondary standards, for bias correction of other faster nondestructive (NDA) methods, or to resolve anomalous measurement results. Presented in this paper are (1) a brief overview of calorimeter advantages and disadvantages, (2) a description of projected large volume calorimeters suitable for waste measurements, and (3) a new technique, direct measurement of transuranic TRU waste alpha-decay activity through calorimetry alone.

  3. Contactless Calorimetry for Levitated Samples

    NASA Technical Reports Server (NTRS)

    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. LC-circuit calorimetry

    SciTech Connect

    Bossen, O.; Schilling, A.

    2011-09-15

    We present a new type of calorimeter in which we couple an unknown heat capacity with the aid of Peltier elements to an electrical circuit. The use of an electrical inductance and an amplifier in the circuit allows us to achieve autonomous oscillations, and the measurement of the corresponding resonance frequency makes it possible to accurately measure the heat capacity with an intrinsic statistical uncertainty that decreases as {approx}t{sub m}{sup -3/2} with measuring time t{sub m}, as opposed to a corresponding uncertainty {approx}t{sub m}{sup -1/2} in the conventional alternating current method to measure heat capacities. We have built a demonstration experiment to show the feasibility of the new technique, and we have tested it on a gadolinium sample at its transition to the ferromagnetic state.

  5. Calorimetry Triggering in ATLAS

    SciTech Connect

    Igonkina, O.; Achenbach, R.; Adragna, P.; Aharrouche, M.; Alexandre, G.; Andrei, V.; Anduaga, X.; Aracena, I.; Backlund, S.; Baines, J.; Barnett, B.M.; Bauss, B.; Bee, C.; Behera, P.; Bell, P.; Bendel, M.; Benslama, K.; Berry, T.; Bogaerts, A.; Bohm, C.; Bold, T.; /UC, Irvine /AGH-UST, Cracow /Birmingham U. /Barcelona, IFAE /CERN /Birmingham U. /Rutherford /Montreal U. /Santa Maria U., Valparaiso /DESY /DESY, Zeuthen /Geneva U. /City Coll., N.Y. /Barcelona, IFAE /CERN /Birmingham U. /Kirchhoff Inst. Phys. /Birmingham U. /Lisbon, LIFEP /Rio de Janeiro Federal U. /City Coll., N.Y. /Birmingham U. /Copenhagen U. /Copenhagen U. /Brookhaven /Rutherford /Royal Holloway, U. of London /Pennsylvania U. /Montreal U. /SLAC /CERN /Michigan State U. /Chile U., Catolica /City Coll., N.Y. /Oxford U. /La Plata U. /McGill U. /Mainz U., Inst. Phys. /Hamburg U. /DESY /DESY, Zeuthen /Geneva U. /Queen Mary, U. of London /CERN /Rutherford /Rio de Janeiro Federal U. /Birmingham U. /Montreal U. /CERN /Kirchhoff Inst. Phys. /Liverpool U. /Royal Holloway, U. of London /Pennsylvania U. /Kirchhoff Inst. Phys. /Geneva U. /Birmingham U. /NIKHEF, Amsterdam /Rutherford /Royal Holloway, U. of London /Rutherford /Royal Holloway, U. of London /AGH-UST, Cracow /Mainz U., Inst. Phys. /Mainz U., Inst. Phys. /Birmingham U. /Hamburg U. /DESY /DESY, Zeuthen /Geneva U. /Kirchhoff Inst. Phys. /Michigan State U. /Stockholm U. /Stockholm U. /Birmingham U. /CERN /Montreal U. /Stockholm U. /Arizona U. /Regina U. /Regina U. /Rutherford /NIKHEF, Amsterdam /Kirchhoff Inst. Phys. /DESY /DESY, Zeuthen /City Coll., N.Y. /University Coll. London /Humboldt U., Berlin /Queen Mary, U. of London /Argonne /LPSC, Grenoble /Arizona U. /Kirchhoff Inst. Phys. /Birmingham U. /Antonio Narino U. /Hamburg U. /DESY /DESY, Zeuthen /Kirchhoff Inst. Phys. /Birmingham U. /Chile U., Catolica /Indiana U. /Manchester U. /Kirchhoff Inst. Phys. /Rutherford /City Coll., N.Y. /Stockholm U. /La Plata U. /Antonio Narino U. /Queen Mary, U. of London /Kirchhoff Inst. Phys. /Antonio Narino U. /Pavia U. /City Coll., N.Y. /Mainz U., Inst. Phys. /Mainz U., Inst. Phys. /Pennsylvania U. /Barcelona, IFAE /Barcelona, IFAE /Chile U., Catolica /Genoa U. /INFN, Genoa /Rutherford /Barcelona, IFAE /Nevis Labs, Columbia U. /CERN /Antonio Narino U. /McGill U. /Rutherford /Santa Maria U., Valparaiso /Rutherford /Chile U., Catolica /Brookhaven /Oregon U. /Mainz U., Inst. Phys. /Barcelona, IFAE /McGill U. /Antonio Narino U. /Antonio Narino U. /Kirchhoff Inst. Phys. /Sydney U. /Rutherford /McGill U. /McGill U. /Pavia U. /Genoa U. /INFN, Genoa /Kirchhoff Inst. Phys. /Kirchhoff Inst. Phys. /Mainz U., Inst. Phys. /Barcelona, IFAE /SLAC /Stockholm U. /Moscow State U. /Stockholm U. /Birmingham U. /Kirchhoff Inst. Phys. /DESY /DESY, Zeuthen /Birmingham U. /Geneva U. /Oregon U. /Barcelona, IFAE /University Coll. London /Royal Holloway, U. of London /Birmingham U. /Mainz U., Inst. Phys. /Birmingham U. /Birmingham U. /Oregon U. /La Plata U. /Geneva U. /Chile U., Catolica /McGill U. /Pavia U. /Barcelona, IFAE /Regina U. /Birmingham U. /Birmingham U. /Kirchhoff Inst. Phys. /Oxford U. /CERN /Kirchhoff Inst. Phys. /UC, Irvine /UC, Irvine /Wisconsin U., Madison /Rutherford /Mainz U., Inst. Phys. /CERN /Geneva U. /Copenhagen U. /City Coll., N.Y. /Wisconsin U., Madison /Rio de Janeiro Federal U. /Wisconsin U., Madison /Stockholm U. /University Coll. London

    2011-12-08

    The ATLAS experiment is preparing for data taking at 14 TeV collision energy. A rich discovery physics program is being prepared in addition to the detailed study of Standard Model processes which will be produced in abundance. The ATLAS multi-level trigger system is designed to accept one event in 2/10{sup 5} to enable the selection of rare and unusual physics events. The ATLAS calorimeter system is a precise instrument, which includes liquid Argon electro-magnetic and hadronic components as well as a scintillator-tile hadronic calorimeter. All these components are used in the various levels of the trigger system. A wide physics coverage is ensured by inclusively selecting events with candidate electrons, photons, taus, jets or those with large missing transverse energy. The commissioning of the trigger system is being performed with cosmic ray events and by replaying simulated Monte Carlo events through the trigger and data acquisition system.

  6. Mound calorimetry for explosive surveillance

    SciTech Connect

    Shockey, G.C.; Rodenburg, W.W.

    1985-01-01

    Heat of reaction determinations of pyrotechnics and explosives is made at MRC-Mound by bomb calorimetry. Energy releases from ten calories to 94 kilocalories have been measured accurately using four different calorimeter systems. Each system is described and some heat of reaction results are given. 3 figs., 4 tabs.

  7. In-situ and simultaneous synchrotron-radiation small-angle and 100 scattering experiments on the low-temperature structure in as-quenched Al-Li alloy during heating

    SciTech Connect

    Okuda, Hiroshi; Tanaka, Ichiro; Matoba, Taro; Osamura, Kozo; Amemiya, Yoshiyuki

    1997-12-01

    The kinetics of phase decomposition in Al-Li alloys has been intensively investigated in the last decade. Experimentally, one or two precursory structures were first found by Nozato et al. in the late seventies by using differential scanning calorimetry (DSC). In order to clarify the nature of the dissolution peak appearing in DSC curves, the authors have conducted in-situ synchrotron-radiation (SR) small-angle and 100 scattering (SAS/100) experiments. During heating an as-quenched sample at the heating rate used in the present DSC experiments, the change of the small-angle scattering, representing the spatial distribution of solute concentration, as well as that of 100 profile, representing the spatial distribution of the local degree of order, has been measured. The structure change obtained from in-situ SAS/100 has been compared with the DSC results.

  8. Thermal stability and molecular microstructure of heat-induced cereal grains, revealed with Raman molecular microspectroscopy and differential scanning calorimetry.

    PubMed

    Khan, Md Majibur Rahman; Yu, Peiqiang

    2013-07-01

    The objectives of the present study were to use Raman molecular microspectroscopy and differential scanning calorimetry (DSC) to reveal molecular thermal stability and thermal degradation behavior of heat-induced cereal grains and reveal the molecular chemistry of the protein structures of cereal grain tissues affected by heat processing and to quantify the protein secondary structures using multicomponent peak modeling Gaussian and Lorentzian methods. Hierarchical cluster analysis (CLA) and principal components analysis (PCA) were also conducted to identify molecular differences in the Raman spectra. Three cereal grain seeds, wheat, triticale, and corn, were used as the model for feed protein in the experiment. The specimens were autoclaved (moist heating) and dry-heated (roasted) at 121 °C for 80 min, respectively. Raman spectroscopy results revealed that there are marked differences in the secondary structures of the proteins subjected to various heating treatments of different cereals. The sensitivity of cereals to moist heating was much higher than the sensitivity to dry heating. The multivariate analyses (CLA and PCA) showed that heat treatment was significantly isolated between the different Raman raw spectra. The DSC study revealed that the thermal degradation behavior of cereals was significantly changed after moist- and dry-heat treatments. The position of the major endothermic peak of dry-heated cereals shifted toward a higher temperature, from 131.7 to 134.0 °C, suggesting the high thermal stability of dry-heated cereals. In contrast, the endothermic peak position was slightly decreased to 132.1 °C in the case of moist autoclaved heating. The digestive behavior and nutritive value of rumen-undegradable protein in animals may be related to the changes of the protein secondary molecular structure and thermal stability of the cereal grain materials, which is attributed by Raman microspectroscopy and DSC endotherm profiles. PMID:23724957

  9. INSTRUMENTS AND METHODS OF INVESTIGATION: Electron-proton separation in calorimetry experiments directly measuring the composition and energy spectrum of cosmic rays

    NASA Astrophysics Data System (ADS)

    Voronov, Sergei A.; Borisov, Stanislav V.; Karelin, Aleksandr V.

    2009-09-01

    Calorimetric particle detectors that play an important role in high-energy cosmic-ray balloon and satellite experiments not only have the major task of measuring energy but also face the problem of identifying electrons and protons. This problem is usually solved by measuring the longitudinal and traverse shower profiles and the total energy release in the calorimeter, using the fact that electromagnetic and hadronic showers differ in their spatial and energy distributions. In this paper, electron and proton identification methods for different types of calorimeters used in cosmic-ray balloon- and satellite-borne experiments are discussed.

  10. Molecular characterization of DSC1 orthologs in invertebrate species.

    PubMed

    Cui, Ying-Jun; Yu, Lin-Lin; Xu, Hai-Jun; Dong, Ke; Zhang, Chuan-Xi

    2012-05-01

    DSC1 and BSC1 are two founding members of a novel family of invertebrate voltage-gated cation channels with close structural and evolutionary relationships to voltage-gated sodium and calcium channels. In this study, we searched the published genome sequences for DSC1 orthologs. DSC1 orthologs were found in all 48 insect species, and in other invertebrate species belonging to phyla Mollusca, Cnidaria, Hemichordata and Echinodermata. However, DSC1 orthologs were not found in four arachnid species, Ixodes scapularis, Rhipicephalus microplus, Tetranychus urticae and Varroa destructor, two species in Annelida or any vertebrate species. We then cloned and sequenced NlSC1 and BmSC1 full-length cDNAs from the brown planthopper (Nilaparvata lugens) and the silkworm (Bombyx mori), respectively. NlSC1 and BmSC1 share about 50% identity with DSC1, and the expression of NlSC1 and BmSC1 transcripts was most abundant in the head and antenna in adults. All DSC1 orthologs contain a unique and conserved DEEA motif, instead of the EEEE or EEDD motif in classical calcium channels or the DEKA motif in sodium channels. Phylogenetic analyses revealed that DSC1 and its orthologs form a separate group distinct from the classical voltage-gated sodium and calcium channels and constitute a unique family of cation channels. The DSC1/BSC1-family channels could be potential targets of new and safe insecticides for pest control. PMID:22321571

  11. Differential scanning calorimetry of coal

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

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

    PubMed

    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. PMID:24856323

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

    PubMed

    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. PMID:24731324

  16. Thermal stability of porcine pepsin influenced by Al(III) ion: DSC study

    NASA Astrophysics Data System (ADS)

    Pavelkić, V. M.; Beljanski, M. V.; Antić, K. M.; Babić, M. M.; Brdarić, T. P.; Gopčević, K. R.

    2011-12-01

    Differential scanning calorimetry (DCS) has been used to determine thermodynamic profile of pepsin and the in vitro effect of Al(III) ions. Thermograms of pepsin unfolding in the presence and absence of aluminum were used to determine the binding constant, K L, in the pepsin-aluminium model system. The thermodynamic parameters were derived from DSC profiles at different ligand concentrations (1, 5 and 10 mM). The temperatures of thermal transitions ( T m), calorimetric (Δ H cal) and van't Hoff enthalpy (Δ H VH), Gibbs free energy, Δ(Δ G), of Al(III) binding to pepsin, as well as an average number of ligands bound to the native protein, were obtained from DSC profiles too. Temperature-dependent changes in the protein structure were also monitored by native PAGE electrophoresis. Increasing the temperature causes the decrease in electrophoretic mobility. Increase in concentration of Al(III) decelerate the migration of pepsin samples on concentration dependent manner. Analysis showed that ligand binding increases thermal stability of protein.

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

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

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

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

    PubMed

    Faroongsarng, Damrongsak

    2016-06-01

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

  19. Calorimetry applied to nucleus-nucleus collisions at ultrarelativistic energies

    SciTech Connect

    Plasil, F.

    1988-01-01

    A general introduction to high-energy calorimetry is presented, together with brief descriptions of the two types of cascades relevant to calorimetric measurements. This is followed by a discussion of ''compensation'' and of the ''e/h'' ratio. A detailed description of two calorimeters designed and constructed for the CERN WA80 experiment are also given. 16 refs., 17 figs., 5 tabs.

  20. Deconvolution Analysis for Classifying Gastric Adenocarcinoma Patients Based on Differential Scanning Calorimetry Serum Thermograms

    PubMed Central

    Vega, Sonia; Garcia-Gonzalez, María Asuncion; Lanas, Angel; Velazquez-Campoy, Adrian; Abian, Olga

    2015-01-01

    Recently, differential scanning calorimetry (DSC) has been acknowledged as a novel tool for diagnosing and monitoring several diseases. This highly sensitive technique has been traditionally used to study thermally induced protein folding/unfolding transitions. In previous research papers, DSC profiles from blood samples of patients were analyzed and they exhibited marked differences in the thermal denaturation profile. Thus, we investigated the use of this novel technology in blood serum samples from 25 healthy subjects and 30 patients with gastric adenocarcinoma (GAC) at different stages of tumor development with a new multiparametric approach. The analysis of the calorimetric profiles of blood serum from GAC patients allowed us to discriminate three stages of cancer development (I to III) from those of healthy individuals. After a multiparametric analysis, a classification of blood serum DSC parameters from patients with GAC is proposed. Certain parameters exhibited significant differences (P < 0.05) and allowed the discrimination of healthy subjects/patients from patients at different tumor stages. The results of this work validate DSC as a novel technique for GAC patient classification and staging, and offer new graphical tools and value ranges for the acquired parameters in order to discriminate healthy from diseased subjects with increased disease burden. PMID:25614381

  1. Pore size distribution in porous glass: fractal dimension obtained by calorimetry

    NASA Astrophysics Data System (ADS)

    Neffati, R.; Rault, J.

    2001-05-01

    By differential Scanning Calorimetry (DSC), at low heating rate and using a technique of fractionation, we have measured the equilibrium DSC signal (heat flow) J q 0 of two families of porous glass saturated with water. The shape of the DSC peak obtained by these techniques is dependent on the sizes distribution of the pores. For porous glass with large pore size distribution, obtained by sol-gel technology, we show that in the domain of ice melting, the heat flow Jq is related to the melting temperature depression of the solvent, Δ T m , by the scaling law: J q 0˜Δ T m - (1 + D). We suggest that the exponent D is of the order of the fractal dimension of the backbone of the pore network and we discuss the influence of the variation of the melting enthalpy with the temperature on the value of this exponent. Similar D values were obtained from small angle neutron scattering and electronic energy transfer measurements on similar porous glass. The proposed scaling law is explained if one assumes that the pore size distribution is self similar. In porous glass obtained from mesomorphic copolymers, the pore size distribution is very sharp and therefore this law is not observed. One concludes that DSC, at low heating rate ( q? 2°C/min) is the most rapid and less expensive method for determining the pore distribution and the fractal exponent of a porous material.

  2. Ionic liquids: differential scanning calorimetry as a new indirect method for determination of vaporization enthalpies.

    PubMed

    Verevkin, Sergey P; Emel'yanenko, Vladimir N; Zaitsau, Dzmitry H; Ralys, Ricardas V; Schick, Christoph

    2012-04-12

    Differential scanning calorimetry (DSC) has been used to measure enthalpies of synthesis reactions of the 1-alkyl-3-methylimidazolium bromide [C(n)mim][Br] ionic liquids from 1-methylimidazole and n-alkyl bromides (with n = 4, 5, 6, 7, and 8). The optimal experimental conditions have been elaborated. Enthalpies of formation of these ionic liquids in the liquid state have been determined using the DSC results according to the Hess Law. The ideal-gas enthalpies of formation of [C(n)mim][Br] were calculated using the methods of quantum chemistry. They were used together with the DSC results to derive indirectly the enthalpies of vaporization of the ionic liquids under study. In order to validate the indirect determination, the experimental vaporization enthalpy of [C(4)mim][Br] was measured by using a quartz crystal microbalance (QCM). The combination of reaction enthalpy measurements by DSC with modern high-level first-principles calculations opens valuable indirect thermochemical options to obtain values of vaporization enthalpies of ionic liquids. PMID:22435356

  3. Calorimetry with meta-crystals

    NASA Astrophysics Data System (ADS)

    Auffray, Etiennette; Lecoq, Paul; Mavromanolakis, Georgios

    2011-04-01

    We present the meta-crystals concept, an approach that consists of using both undoped and properly doped heavy crystal fibers of identical material as the active medium of a calorimeter. The undoped fibers behave as Cherenkov radiators while the doped ones behave as scintillators. A dual readout calorimeter can be built with its sensitive volume composed of a mixture of both types of crystals. In addition if the calorimeter is adequately finely segmented it can also function as a particle flow calorimeter at the same time. In this way one could possibly combine the advantages of both the particle flow concept and the dual-readout scheme. We discuss the approach of dual readout calorimetry with meta-crystals made of Lutetium Aluminium Garnet (LuAG) and present studies on the material development, first testbeam activities and results based on simulation for understanding the performance trends. We close with a brief outlook on open issues and further R&D needed to proceed from an ideal conceptual case to the design of a realistic detector.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

  6. Applying differential scanning calorimetry to characterize chemical-protective-clothing materials. Final report

    SciTech Connect

    Weidenbaum, S.S.

    1991-01-01

    The use of differential scanning calorimetry as a means of evaluating changes in polymers used to manufacture protective clothing was investigated. Separate enclosed Appendices give details of studies dealing with Vitron (R)/chlorobutyl laminate. These are preceded by a Summary which gives information dealing with Teflon-coated Nomex (Challenge (TM) 5100). The manner in which DSC graphs were affected by exposing the polymers to a variety of chemicals is the main subject of the report. However, some information dealing with thermogravimetric analysis (TGA), viscoelastic measurements and solubility parameters is also in the various appendices.

  7. Accurate Measurement of Heat Capacity by Differential Scanning Calorimetry

    NASA Technical Reports Server (NTRS)

    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.

  8. Automatic calorimetry system monitors RF power

    NASA Technical Reports Server (NTRS)

    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.

  9. Immersion Calorimetry: Molecular Packing Effects in Micropores.

    PubMed

    Madani, S Hadi; Silvestre-Albero, Ana; Biggs, Mark J; Rodríguez-Reinoso, Francisco; Pendleton, Phillip

    2015-12-21

    Repeated and controlled immersion calorimetry experiments were performed to determine the specific surface area and pore-size distribution (PSD) of a well-characterized, microporous poly(furfuryl alcohol)-based activated carbon. The PSD derived from nitrogen gas adsorption indicated a narrow distribution centered at 0.57±0.05 nm. Immersion into liquids of increasing molecular sizes ranging from 0.33 nm (dichloromethane) to 0.70 nm (α-pinene) showed a decreasing enthalpy of immersion at a critical probe size (0.43-0.48 nm), followed by an increase at 0.48-0.56 nm, and a second decrease at 0.56-0.60 nm. This maximum has not been reported previously. After consideration of possible reasons for this new observation, it is concluded that the effect arises from molecular packing inside the micropores, interpreted in terms of 2D packing. The immersion enthalpy PSD was consistent with that from quenched solid density functional theory (QSDFT) analysis of the nitrogen adsorption isotherm. PMID:26394883

  10. Melting by temperature-modulated calorimetry

    SciTech Connect

    Wunderlich, B.; Okazaki, Iwao; Ishikiriyama, Kazuhiko; Boller, A. |

    1997-09-01

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

  11. Current status of tritium calorimetry at TLK

    SciTech Connect

    Buekki-Deme, A.; Alecu, C.G.; Kloppe, B.; Bornschein, B.

    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)

  12. Thermal Properties of Silk Fibroin Using Fast Scanning Calorimetry

    NASA Astrophysics Data System (ADS)

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

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

  13. PALS and DSC measurements in 8 MeV electron irradiated natural rubber filled with different fillers

    NASA Astrophysics Data System (ADS)

    Mandal, Arunava; Pan, Sandip; Roychowdhury, Anirban; Sengupta, Asmita

    2015-10-01

    The effect of high energy electron irradiation on the microstructure and thermal properties of natural rubber (NR) filled with different fillers at different concentrations are studied. The samples are irradiated with 8 MeV electron beam to a total dose of 100 KGy. The change in free volume size and specific heat due to addition of fillers and irradiation are studied using positron annihilation lifetime spectroscopy (PALS) and differential scanning calorimetry (DSC) respectively. The Positron lifetime spectra are de-convoluted into two components. The longer lived component (τo-Ps) signifies the pick-off annihilation of ortho-positronium (o-Ps) at free volume site which may be related to the radius of the free volume holes. It is observed that the specific heat (Cp) and free volume size are all affected by both irradiation and addition of fillers.

  14. DSC -- Disruption Simulation Code for Tokamaks and ITER applications

    NASA Astrophysics Data System (ADS)

    Galkin, S. A.; Grubert, J. E.; Zakharov, L. E.

    2010-11-01

    Arguably the most important issue facing the further development of magnetic fusion via advanced tokamaks is to predict, avoid, or mitigate disruptions. This recently became the hottest challenging topic in fusion research because of several potentially damaging effects, which could impact the ITER device. To address this issue, two versions of a new 3D adaptive Disruption Simulation Code (DSC) will be developed. The first version will solve the ideal reduced 3D MHD model in the real geometry with a thin conducting wall structure, utilizing the adaptive meshless technique. The second version will solve the resistive reduced 3D MHD model in the real geometry of the conducting structure of the tokamak vessel and will finally be parallelized. The DSC will be calibrated against the JET disruption data and will be capable of predicting the disruption effects in ITER, as well as contributing to the development of the disruption mitigation scheme and suppression of the RE generation. The progress on the first version of the 3D DSC development will be presented.

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

    PubMed

    Bley, O; Siepmann, J; Bodmeier, R

    2009-02-01

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

  16. Particle Flow Calorimetry at the ILC

    SciTech Connect

    Thomson, M. A.

    2007-03-19

    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/{radical}(E(GeV)). In contrast to the traditional approach to calorimetry, potentially the performance of particle flow calorimetry is sensitive to the detailed structure of hadronic showers. 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. First detector optimisation studies are presented and the aspects of hadronic showers which are most likely to impact particle flow performance are discussed.

  17. Dsc orthologs are required for hypoxia adaptation, triazole drug responses, and fungal virulence in Aspergillus fumigatus.

    PubMed

    Willger, Sven D; Cornish, E Jean; Chung, Dawoon; Fleming, Brittany A; Lehmann, Margaret M; Puttikamonkul, Srisombat; Cramer, Robert A

    2012-12-01

    Hypoxia is an environmental stress encountered by Aspergillus fumigatus during invasive pulmonary aspergillosis (IPA). The ability of this mold to adapt to hypoxia is important for fungal virulence and genetically regulated in part by the sterol regulatory element binding protein (SREBP) SrbA. SrbA is required for fungal growth in the murine lung and to ultimately cause lethal disease in murine models of IPA. Here we identified and partially characterized four genes (dscA, dscB, dscC, and dscD, here referred to as dscA-D) with previously unknown functions in A. fumigatus that are orthologs of the Schizosaccharomyces pombe genes dsc1, dsc2, dsc3, and dsc4 (dsc1-4), which encode a Golgi E3 ligase complex critical for SREBP activation by proteolytic cleavage. A. fumigatus null dscA-D mutants displayed remarkable defects in hypoxic growth and increased susceptibility to triazole antifungal drugs. Consistent with the confirmed role of these genes in S. pombe, both ΔdscA and ΔdscC resulted in reduced cleavage of the SrbA precursor protein in A. fumigatus. Inoculation of corticosteroid immunosuppressed mice with ΔdscA and ΔdscC strains revealed that these genes are critical for A. fumigatus virulence. Reintroduction of SrbA amino acids 1 to 425, encompassing the N terminus DNA binding domain, into the ΔdscA strain was able to partially restore virulence, further supporting a mechanistic link between DscA and SrbA function. Thus, we have shown for the first time the importance of a previously uncharacterized group of genes in A. fumigatus that mediate hypoxia adaptation, fungal virulence, and triazole drug susceptibility and that are likely linked to regulation of SrbA function. PMID:23104569

  18. Calibration of Chemical Kinetic Models Using Simulations of Small-Scale Cookoff Experiments

    SciTech Connect

    Wemhoff, A P; Becker, R C; Burnham, A K

    2008-02-26

    Establishing safe handling limits for explosives in elevated temperature environments is a difficult problem that often requires extensive simulation. The largest influence on predicting thermal cookoff safety lies in the chemical kinetic model used in these simulations, and these kinetic model reaction sequences often contain multiple steps. Several small-scale cookoff experiments, notably Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), One-Dimensional Time-to-Explosion (ODTX), and the Scaled Thermal Explosion (STEX) have been performed on various explosives to aid in cookoff behavior determination. Past work has used a single test from this group to create a cookoff model, which does not guarantee agreement with the other experiments. In this study, we update the kinetic parameters of an existing model for the common explosive 2,4,6-Trinitrotoluene (TNT) using DSC and ODTX experimental data at the same time by minimizing a global Figure of Merit based on hydrodynamic simulated data. We then show that the new kinetic model maintains STEX agreement, reduces DSC agreement, and improves ODTX and TGA agreement when compared to the original model. In addition, we describe a means to use implicit hydrodynamic simulations of DSC experiments to develop a reaction model for TNT melting.

  19. Liquid Argon Calorimetry for ATLAS

    NASA Astrophysics Data System (ADS)

    Robinson, Alan

    2008-05-01

    This summer, the largest collaborative physics project since the Manhattan project will go online. One of four experiments for the Large Hadron Collider at CERN in Geneva, ATLAS, employs over 2000 people. Canadians have helped design, construct, and calibrate the liquid argon calorimeters for ATLAS to capture the products of the high energy collisions produced by the LHC. From an undergraduate's perspective, explore how these calorimeters are made to handle their harsh requirement. From nearly a billion proton-proton collisions a second, physicists hope to discover the Higgs boson and other new fundamental particles.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

    We are conducting DSC/EGA experiments at Mars ambient temperature and pressure using the TEGA engineering model. These tests illustrate the outstanding capabilities of a TEGA-like instrument on the surface of Mars.

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

    PubMed Central

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

    2013-01-01

    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. PMID:24421540

  3. Liquid argon calorimetry for the SSC

    SciTech Connect

    Gordon, H.A.

    1990-01-01

    Liquid argon calorimetry is a mature technique. However, adapting it to the challenging environment of the SSC requires a large amount of R D. The advantages of the liquid argon approach are summarized and the issues being addressed by the R D program are described. 18 refs.

  4. Isothermal Titration Calorimetry in the Student Laboratory

    ERIC Educational Resources Information Center

    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…

  5. Calculation of Temperature Rise in Calorimetry.

    ERIC Educational Resources Information Center

    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)

  6. Final Technical Report CMS fast optical calorimetry

    SciTech Connect

    Winn, David R.

    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. A sample-saving method for heat capacity measurements on powders using relaxation calorimetry.

    PubMed

    Dachs, Edgar; Benisek, Artur

    2011-08-01

    An experimental method is described for determining the low-temperature heat capacity (C(p)) of mg-sized powder samples using the Quantum Design "Physical Properties Measurement System" (PPMS). The powder is contained in an Al pan as an ∼1 mm thick compressed layer. The sample is not mixed with Apiezon N grease, as compared to other methods. Thus, it is not contaminated and can be used for further study. This is necessary for samples that are only available in tiny amounts. To demonstrate the method various samples, all insulating in nature, were studied including benzoic acid, sapphire and different silicate minerals. The measurements show that the method has an accuracy in C(p) to better than 1% at T above 30-50 K and ±3-5% up to ±10% below. The experimental procedure is based on three independent PPMS and three independent differential scanning calorimetry (DSC) measurements. The DSC C(p) data are used to slightly adjust the PPMS C(p) data by a factor CpDSC/CpPPMSat298K. This is done because heat capacities measured with a DSC device are more accurate around ambient T (⩽0.6%) than PPMS values and is possible because the deviation of PPMS heat capacities from reference values is nearly constant between about 50 K and 300 K. The resulting standard entropies agree with published reference values within 0.21% for the silicates, by 0.34% for corundum, and by 0.9% for powdered benzoic acid. The method thus allows entropy determinations on powders with an accuracy of better than 1%. The advantage of our method compared to other experimental techniques is that the sample powder is not contaminated with grease and that heat capacity values show less scatter at high temperatures. PMID:21886915

  8. Investigation of MSWI fly ash melting characteristic by DSC-DTA

    SciTech Connect

    Li, Rundong Wang, Lei; Yang, Tianhua; Raninger, Bernhard

    2007-07-01

    The melting process of MSWI (Municipal Solid Waste Incineration) fly ash has been studied by high-temperature DSC-DTA experiments. The experiments were performed at a temperature range of 20-1450 deg. C, and the considerable variables included atmosphere (O{sub 2} and N{sub 2}), heating rates (5 deg. C/min, 10 deg. C/min, 20 deg. C/min) and CaO addition. Three main transitions were observed during the melting process of fly ash: dehydration, polymorphic transition and fusion, occurring in the temperature range of 100-200 deg. C, 480-670 deg. C and 1101-1244 deg. C, respectively. The apparent heat capacity and heat requirement for melting of MSWI fly ash were obtained by DSC (Differential Scanning Calorimeter). A thermodynamic modeling to predict the heat requirements for melting process has been presented, and it agrees well with the experimental data. Finally, a zero-order kinetic model of fly ash melting transition was established. The apparent activation energy of MSWI fly ash melting transition was obtained.

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

    NASA Astrophysics Data System (ADS)

    Stavrou, E.; Tsiantos, C.; Tsopouridou, R. D.; Kripotou, S.; Kontos, A. G.; Raptis, C.; Capoen, B.; Bouazaoui, M.; Turrell, S.; Khatir, S.

    2010-05-01

    Raman scattering and differential scanning calorimetry (DSC) measurements have been carried out on four mixed tellurium-zinc oxide (TeO2)1 - x(ZnO)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 Tg has been determined for each glass, showing a monotonous decrease of Tg 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 Td very close to the respective Tg 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 Tg 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 Tg and confirms the correlation between the BP and the MRO of glasses.

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

    PubMed

    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. PMID:24611844

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

    NASA Astrophysics Data System (ADS)

    Gal, O.; Kostoski, D.; Babić, D.; Stannett, V. T.

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

  12. Study of the thermal behavior of choline ibuprofenate using differential scanning calorimetry and hot-stage microscopy

    NASA Astrophysics Data System (ADS)

    Diogo, Hermínio P.; Moura Ramos, Joaquim J.

    2014-12-01

    The phase transformations in choline ibuprofenate, [chol][ibu], have been studied by differential scanning calorimetry (DSC) and hot-stage microscopy (HSM). Two crystalline forms, α and β, were identified that are very different in their thermal behavior, and thus probably very different in their crystal structures. The melting temperatures of the two crystal polymorphs differ as much as 50°. The higher temperature polymorph, α, presents a sharp and fast crystallization process, while the melting transformation displays a very slow dynamics. The β polymorph forms on cooling through a broad crystal-to-crystal transformation, and displays a melting process that is sharp compared with that of α polymorph.

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

    SciTech Connect

    Dan, Kaustabh Roy, Madhusudan Datta, Alokmay

    2014-04-24

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

  14. DSC and Raman studies of silver borotellurite glasses

    NASA Astrophysics Data System (ADS)

    Kaur, Amandeep; Khanna, Atul; Gonzàlez, Fernando

    2016-05-01

    Silver borotellurite glasses of composition: xAg2O-yB2O3-(100-x-y)TeO2 (x=20-mol%, y = 0, 10, 20 and 30-mol%) were prepared and characterized by density, X-ray diffraction (XRD), differential scanning calorimetry, and Raman spectroscopy. XRD confirmed the amorphous structure of all samples. Density of glasses decreases while the glass transition temperature increases with increase in B2O3 content from 10 to 30-mol%. Raman study shows that coordination number of Te with oxygen decreases steadily from 3.42 to 3.18 on adding B2O3 due to the transformation of TeO4 into TeO3 units.

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

    PubMed

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

    2015-07-01

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

  16. A study of the aging of silicone breast implants using 29Si, 1H relaxation and DSC measurements.

    PubMed

    Birkefeld, Anja Britta; Eckert, Hellmut; Pfleiderer, Bettina

    2004-08-01

    In this study 26 previously implanted silicone breast implants from the same manufacturer (Dow Corning) were investigated with two different analytical methods to characterize potential aging processes such as migration of monomer material from the gel and shell to local and distant sites, chemical alterations of the polymer, and infiltration of body compounds such as lipids. (1)H and (29)Si NMR relaxation measurements (spin-lattice, T1, and spin-spin, T2, relaxation times) were used to study the molecular dynamics of polysiloxane chains, both in gels and in shells. In addition, changes in physical properties were monitored by differential scanning calorimetry (DSC). The results of these measurements indicate that NMR relaxation times are influenced by implant generation, implantation time, shell texture and implant status. (1)H T2 values of shells and gels show a tendency to increase with increasing implantation time, indicating higher mobility and possible disintegration of the polymer network of older implants. Furthermore, the data suggest that aging also involves the migration of low cyclic molecular weight (LMW) silicone and linear chain polymer material from the gels into the shells. The high "bleeding" rate of second-generation (G2) implants (implantation period around 1973-1985), exhibiting thin shells is reflected in reduced relaxation times of these devices, most likely due to a loss of low molecular weight fractions from the gels. Moreover, "gel bleeding" also influences the melting behavior observed in DSC studies. Increased shell rigidity (high Tm and Tg) tends to be correlated with longer (29)Si relaxation times of the corresponding gels, suggesting a reduced transfer of LMW silicones and linear chain polymer from the gel to the shell and to the outside. Remarkably, textured implants seem to be less susceptible to degradation processes than implants with thin shells. PMID:15046931

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

    PubMed

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

    2013-10-01

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

  18. Black carbon quantification in charcoal-enriched soils by differential scanning calorimetry

    NASA Astrophysics Data System (ADS)

    Hardy, Brieuc; Cornelis, Jean-Thomas; Leifeld, Jens

    2015-04-01

    Black carbon (BC), the solid residue of the incomplete combustion of biomass and fossil fuels, is ubiquitous in soil and sediments, fulfilling several environmental services such as long-term carbon storage. BC is a particularly important terrestrial carbon pool due to its large residence time compared to thermally unaltered organic matter, which is largely attributed to its aromatic structure. However, BC refers to a wide range of pyrogenic products from partly charred biomass to highly condensed soot, with a degree of aromaticity and aromatic condensation varying to a large extend across the BC continuum. As a result, BC quantification largely depends on operational definitions, with the extraction efficiency of each method varying across the entire BC range. In our study, we investigated the adequacy of differential scanning calorimetry (DSC) for the quantification of BC in charcoal-enriched soils collected in the topsoil of pre-industrial charcoal kilns in forest and cropland of Wallonia, Belgium, where charcoal residues are mixed to uncharred soil organic matter (SOM). We compared the results to the fraction of the total organic carbon (TOC) resisting to K2Cr2O7 oxidation, another simple method often used for BC measurement. In our soils, DSC clearly discriminates SOM from chars. SOM is less thermally stable than charcoal and shows a peak maximum around 295°C. In forest and agricultural charcoal-enriched soils, three peaks were attributed to the thermal degradation of BC at 395, 458 and 523°C and 367, 420 and 502 °C, respectively. In cropland, the amount of BC calculated from the DSC peaks is closely related (slope of the linear regression = 0.985, R²=0.914) to the extra organic carbon content measured at charcoal kiln sites relative to the charcoal-unaffected adjacent soils, which is a positive indicator of the suitability of DSC for charcoal quantification in soil. The first BC peak, which may correspond to highly degraded charcoal, contributes to a

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

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

    PubMed

    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. PMID:23314800

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

    NASA Astrophysics Data System (ADS)

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

    2013-01-01

    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.

  2. Differential scanning calorimetry of whole Escherichia coli treated with the antimicrobial peptide MSI-78 indicate a multi-hit mechanism with ribosomes as a novel target

    PubMed Central

    Brannan, Alexander M.; Whelan, William A.; Cole, Emma

    2015-01-01

    Differential Scanning Calorimetry (DSC) of intact Escherichia coli (E. coli) was used to identify non-lipidic targets of the antimicrobial peptide (AMP) MSI-78. The DSC thermograms revealed that, in addition to its known lytic properties, MSI-78 also has a striking effect on ribosomes. MSI-78’s effect on DSC scans of bacteria was similar to that of kanamycin, an antibiotic drug known to target the 30S small ribosomal subunit. An in vitro transcription/translation assay helped confirm MSI-78’s targeting of ribosomes. The scrambled version of MSI-78 also affected the ribosome peak of the DSC scans, but required greater amounts of peptide to cause a similar effect to the unscrambled peptide. Furthermore, the effect of the scrambled peptide was not specific to the ribosomes; other regions of the DSC thermogram were also affected. These results suggest that MSI-78’s effects on E. coli are at least somewhat dependent on its particular structural features, rather than a sole function of its overall charge and hydrophobicity. When considered along with earlier work detailing MSI-78’s membrane lytic properties, it appears that MSI-78 operates via a multi-hit mechanism with multiple targets. PMID:26713257

  3. Calorimetry of the CMD-3 detector

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

  4. A sample-saving method for heat capacity measurements on powders using relaxation calorimetry

    NASA Astrophysics Data System (ADS)

    Dachs, Edgar; Benisek, Artur

    2011-08-01

    An experimental method is described for determining the low-temperature heat capacity (Cp) of mg-sized powder samples using the Quantum Design “Physical Properties Measurement System” (PPMS). The powder is contained in an Al pan as an ∼1 mm thick compressed layer. The sample is not mixed with Apiezon N grease, as compared to other methods. Thus, it is not contaminated and can be used for further study. This is necessary for samples that are only available in tiny amounts. To demonstrate the method various samples, all insulating in nature, were studied including benzoic acid, sapphire and different silicate minerals. The measurements show that the method has an accuracy in Cp to better than 1% at T above 30-50 K and ±3-5% up to ±10% below. The experimental procedure is based on three independent PPMS and three independent differential scanning calorimetry (DSC) measurements. The DSC Cp data are used to slightly adjust the PPMS Cp data by a factor C. This is done because heat capacities measured with a DSC device are more accurate around ambient T (⩽0.6%) than PPMS values and is possible because the deviation of PPMS heat capacities from reference values is nearly constant between about 50 K and 300 K. The resulting standard entropies agree with published reference values within 0.21% for the silicates, by 0.34% for corundum, and by 0.9% for powdered benzoic acid. The method thus allows entropy determinations on powders with an accuracy of better than 1%. The advantage of our method compared to other experimental techniques is that the sample powder is not contaminated with grease and that heat capacity values show less scatter at high temperatures.

  5. Calorimetry exchange program. Annual report, 1988

    SciTech Connect

    Lyons, J.E.

    1988-12-31

    The goals of the Calorimetry Sample Program are: 1. Discuss measurement differences, 2. Review and improve analytical measurements and methods, 3. Discuss new measurement capabilities, 4. Provide data to DOE on measurement capabilities to evaluate shipper- receiver differences, 5. Provide characterized or standard materials as necessary for exchange participants, 6. Provide a measurement control program for plutonium analysis. A sample of PuO{sub 2} powder is available at each participating site for NDA measurement, including either or both calorimetry and high-resolution gamma-ray spectroscopy, the elements which are typically combined to provide a calorimetric assay of plutonium. The facilities measure the sample as frequently and to the level of precision which they desire, and then submit the data to the Exchange for analysis. Statistical tests are used to evaluate the data and to determine if there are significant differences from accepted values for the exchange or from data previously reported by that facility. Data included in this report is a compilation of all exchange data received in 1988. Since a large number of data points were recorded, a change was made to the analysis method to account for the uncertainty in the accepted values.

  6. Electronics for calorimetry: An overview of requirements

    SciTech Connect

    Radeka, V.

    1995-10-01

    Calorimetry in large detectors at LHC poses some requirements on readout electronics which are quite different than for central tracking and muon tracking. The main distinction is, (a) in the large dynamic range of the energies to be measured; and (b) uniformity of response and accuracy of calibration over the whole detector. As in all other functions of the detector, low noise is essential. High luminosity results in pileup effects, which are present in every measurement, and in high radiation for front and forward parts of the calorimeter. Power dissipation and cooling is a concern as in any other detector component, in some respects only more so, since all the elements of the signal processing chain require more power due to the large dynamic range, speed of response, high precision and low noise required. The key requirements on the calorimetry readout electronics are briefly discussed here, with an emphasis on the dynamic range. While there are quite significant differences in the principles and technology among the crystals, tiles with fibers and liquid ionization, the signal is finally reduced to a charge measurement from a capacitive source in all three cases, and the signal processing chain becomes remarkably identical.

  7. Isothermal Titration Calorimetry and Macromolecular Visualization for the Interaction of Lysozyme and Its Inhibitors

    ERIC Educational Resources Information Center

    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…

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

    PubMed

    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. PMID:24863760

  9. 47 CFR 80.359 - Frequencies for digital selective calling (DSC).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Frequencies for digital selective calling (DSC). 80.359 Section 80.359 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES Frequencies Radiotelegraphy § 80.359 Frequencies for digital selective calling (DSC)....

  10. 47 CFR 80.103 - Digital selective calling (DSC) operating procedures.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 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 2011-10-01 2011-10-01 false Digital selective calling (DSC) operating... Procedures-General § 80.103 Digital selective calling (DSC) operating procedures. (a) Operating...

  11. Characterization of supercooled liquid Ge2Sb2Te5 and its crystallization by ultrafast-heating calorimetry.

    PubMed

    Orava, J; Greer, A L; Gholipour, B; Hewak, D W; Smith, C E

    2012-04-01

    Differential scanning calorimetry (DSC) is widely used to study the stability of amorphous solids, characterizing the kinetics of crystallization close to the glass-transition temperature T(g). We apply ultrafast DSC to the phase-change material Ge(2)Sb(2)Te(5) (GST) and show that if the range of heating rates is extended to more than 10(4) K s(-1), the analysis can cover a wider temperature range, up to the point where the crystal growth rate approaches its maximum. The growth rates that can be characterized are some four orders of magnitude higher than in conventional DSC, reaching values relevant for the application of GST as a data-storage medium. The kinetic coefficient for crystal growth has a strongly non-Arrhenius temperature dependence, revealing that supercooled liquid GST has a high fragility. Near T(g) there is evidence for decoupling of the crystal-growth kinetics from viscous flow, matching the behaviour for a fragile liquid suggested by studies on oxide and organic systems. PMID:22426461

  12. Study of the Crystalline Morphology Evolution of PET and PET/PC Blends by Time-resolved Synchrotron Small Angle X-ray Scattering (SAXS) and DSC

    SciTech Connect

    Barbosa, Irineu; Larocca, Nelson M.; Hage, Elias; Plivelic, Tomas S.; Torriani, Iris L.; Mantovani, Gerson L.

    2009-01-29

    Isothermal melt crystallization of poly(ethylene terephthalate)(PET) and PET/PC (polycarbonate) blend, with and without a transesterification catalyst, was studied by time-resolved small-angle X-ray scattering (SAXS) and differential scanning calorimetry (DSC) in order to achieve the variation of the morphological parameters throughout the whole crystallization time. For neat PET, the catalyst promotes a decrease of the crystal lamellar thickness but for the blend no variations were observed. The effect of incorporation of catalyst in crystallization kinetics was very distinct in PET pure and the blend: in the former the catalyst leads to an increase of this kinetics while for the latter it was observed a decreasing.

  13. Calorimetry for Fast Authentication of Edible Oils

    NASA Astrophysics Data System (ADS)

    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.

  14. Calorimetry At Very High Energy Colliders

    SciTech Connect

    Chiu, Mickey

    2011-06-01

    The capability of hadron colliders has increased to where it will soon be possible to collide protons at center of mass energies of 14 TeV with the advent of the LHC. With increasing collision energy, calorimeters become ever more essential components of a detector, and collaborations often choose very different technologies to meet their goals. From the perspective of a high energy particle and nuclear physicist, a survey is presented of the differences in design considerations and actual performance of the wide variety of calorimeters used in modern hadron colliders such as the Tevatron, RHIC, and LHC. The lessons learned and some ideas for future development of calorimetry will also be discussed.

  15. Synergies between electromagnetic calorimetry and PET

    SciTech Connect

    Moses, William W.

    2002-07-30

    The instrumentation used for the nuclear medical imaging technique of Positron Emission Tomography (PET) shares many features with the instrumentation used for electromagnetic calorimetry. Both fields can certainly benefit from technical advances in many common areas, and this paper discusses both the commonalties and the differences between the instrumentation needs for the two fields. The overall aim is to identify where synergistic development opportunities exist. While such opportunities exist in inorganic scintillators, photodetectors, amplification and readout electronics, and high-speed computing, it is important to recognize that while the requirements of the two fields are similar, they are not identical, and so it is unlikely that advances specific to one field can be transferred without modification to the other.

  16. Advanced ion beam calorimetry for the test facility ELISE

    SciTech Connect

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

    2015-04-08

    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 m{sup 2} 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 m{sup 2}, 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

  17. Advanced ion beam calorimetry for the test facility ELISE

    NASA Astrophysics Data System (ADS)

    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

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

    SciTech Connect

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

    2015-02-01

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

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

    PubMed

    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. PMID:26794362

  20. Differential scanning calorimetry of plant cell walls

    SciTech Connect

    Lin, Liangshiou; Varner, J.E. ); Yuen, H.K. )

    1991-03-15

    High-sensitivity differential scanning calorimetry has been used to study the phase transition of cell wall preparations of the elongating and mature regions of soybean hypocotyls and of celery epidermis and collenchyma strands. A step-like transition believed to be glass transition was observed in walls isolated from the elongating region of soybean hypocotyls at 52.9C. Addition of 1 mM CaCl{sub 2} to the cell wall preparation increased the transition temperature to 60.8C and greatly reduced the transition magnitude. In walls from the mature region, the transition was small and occurred at a higher temperature (60.1C). Addition of calcium to the mature region cell wall had little effect on the transition. Based on the known interactions between calcium and pectin, the authors propose that calcium affects the glass transition by binding to the polygalacturonate backbone of wall pectin, resulting in a more rigid wall with a smaller transition at a higher temperature. The mature region either has more calcium in the wall or has more methyl-esterified pectin, making it less responsive to added calcium.

  1. Calorimetry using organic scintillators, 'a sideways perspective'.

    SciTech Connect

    Proudfoot, J.

    1999-09-10

    Over the last two decades, calorimetry baaed on organic scintillators has developed into an excellent technology for many experimental situations in high energy physics. The primary difficulty, that of extracting the light signals, has benefited from two milestone innovations. The first was the use of wavelength-shifting bars to allow light to be efficiently collected from large areas of scintillator and then readily piped to a readout device. The second of these was the extension of this approach to plastic wavelength-shifting optical fibers whose great flexibility and small diameter allowed a minimum of detector volume to be compromised by the read-out. These two innovations coupled with inventiveness have produced many varied and successful calorimeters. Equal response to both hadronic and electromagnetic showers can be realized in scintillator-based calorimeters. However, in general this is not the case and it is likely that in the search for greater performance, in the future, combined tracking and calorimeter systems will be required.

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

    SciTech Connect

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

    2010-10-22

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

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

    PubMed

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

    2010-08-01

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

  4. Quantifying Natural Organic Matter with Calorimetry - assessing system complexity to build a central view C stability

    NASA Astrophysics Data System (ADS)

    Liles, G. C.; Bower, J.; Henneberry, Y.; Horwath, W. R.

    2010-12-01

    Characterizing the status and stability of natural organic matter (NOM) is central to understanding the flux, attenuation and function of C in the biosphere. A diversity of stabilizing factors (climate, mineralogy, chemical recalcitrance) have required a range of analytical approaches and methods that are site or discipline specific making unified assessments difficult. Aggregated, these efforts support our working models of NOM as a dynamic body but, overall, lack analytical simplicity and reproducibility. In particular, the robustness and resolution to assess NOM across systems of increasing complexity is lacking. Calorimetry has been central to chemistry and material science characterizing a broad range of organic and inorganic materials and their mixtures illustrating composition, purity and stability. Differential scanning calorimetry - thermogravimetry (DSC-TG) provides the flexibility and resolution to quantify the complexity found within NOM with precise quantification of material mass loss (TG) and energetic (DSC) under controlled atmospheric and heating conditions. DSC-TG is data rich providing a range of qualitative and quantitative metrics: peak shape, exothermic energy yield, mass loss, and determination of enthalpy, to characterize NOM stability from low (dissolved organic carbon - DOC) through high (compost and soils) molecular weights (MW) at increasing levels of organo-metallic complexity. Our research investigates the influence of biochemical recalcitrance and its alteration by oxides employing three natural systems of varying complexity as experimental models: aquatic - DOC and DOC with metal flocculants (low MW - low complexity), compost - processed with and without metal oxides (mixed MW - increasing complexity) and forest soils - under varying management and litter inputs (mixed MW - most complexity). Samples were analyzed by DSC-TG (zero-air - 20 C/min - ambient to > 800C) and assessed for three temperature/exothermic reaction regions (200

  5. Interaction between vitamin D 2 and magnesium in liposomes: Differential scanning calorimetry and FTIR spectroscopy studies

    NASA Astrophysics Data System (ADS)

    Toyran, Neslihan; Severcan, Feride

    2007-08-01

    Magnesium (Mg 2+) ion is of great importance in physiology by its intervention in 300 enzymatic systems, its role in membrane structure, its function in neuromuscular excitability and vitamin D metabolism and/or action. In the present study, the interaction of Mg 2+, at low (1 mole %) and high (7 mole %) concentrations with dipalmitoyl phosphatidylcholine (DPPC) liposomes has been studied in the presence and absence of vitamin D 2 (1 mole %) by using two noninvasive techniques, namely differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy. DSC studies reveal that the presence of vitamin D 2 in the pure or Mg 2+ (at both low and high concentrations) containing liposomes diminishes the pretransition. The calorimetric results also reveal that, inclusion of Mg 2+ (more significantly at high concentration) into pure or vitamin D 2 containing DPPC liposomes increases the main phase transition temperature. The investigation of the CH 2 symmetric, the CH 3 asymmetric, the C dbnd O stretching, and the PO2- antisymmetric double bond stretching bands in FTIR spectra with respect to changes occurring in the wavenumber and/or the bandwidth values as a function of temperature reveal that, inclusion of vitamin D 2 or Mg 2+ into pure DPPC liposomes orders and decreases the dynamics of the acyl chains in both gel and liquid-crystalline phases and does not induce hydrogen bond formation in the interfacial region. Furthermore, the dynamics of the head groups of the liposomes decreases in both phases. Our findings reveal that, simultaneous presence of vitamin D 2 and Mg 2+ alters the effect of each other, which is reflected as a decrease in the interactions between these two additives within the model membrane.

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

    PubMed

    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. PMID:26004556

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

    PubMed

    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 (P<0.001) and-0.610 (P<0.001) respectively. ROC curves demonstrated that when rASL ≤0.585, the sensitivity, specificity and accuracy for predicting ROIs with rCBF<0.9 were 92.3%, 63.6% and 76.6% respectively. When rASL ≤0.952, the sensitivity, specificity and accuracy for predicting ROIs rMTT>1.0 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. PMID:26670447

  8. Molecular mobility studies on the amorphous state of disaccharides. I-thermally stimulated currents and differential scanning calorimetry.

    PubMed

    Pinto, Susana S; Diogo, Hermínio P; Nunes, Teresa G; Moura Ramos, Joaquim J

    2010-08-16

    The relaxational processes in amorphous solid gentiobiose and cellobiose are studied by thermally stimulated depolarization currents (TSDC) in the temperature region from 108K up to 423K. The slow molecular mobility was characterized in the crystal and in the glassy state. The features of different motional components of the secondary relaxation have been monitored as a function of time as the glass structurally relaxes on aging. It is concluded that some modes of motion of this mobility are aging independent, while others are affected by aging. The value of the steepness index or fragility (T(g)-normalized temperature dependence of the relaxation time) was obtained by differential scanning calorimetry (DSC) from the analysis of the scanning rate dependency of T(g). PMID:20591418

  9. Confined water in controlled pore glass CPG-10-120 studied by positron annihilation lifetime spectroscopy and differential scanning calorimetry

    NASA Astrophysics Data System (ADS)

    Šauša, O.; Mat'ko, I.; Illeková, E.; Macová, E.; Berek, D.

    2015-06-01

    The solidification and melting of water confined in the controlled pore glass (CPG) with average pore size 12.6 nm has been studied by differential scanning calorimetry (DSC) and positron annihilation lifetime spectroscopy (PALS). The fully-filled sample of CPG by water as well as the samples of CPG with different content of water were used. The measurements show the presence of amorphous and crystalline phases of water in this type and size of pores, freezing point depression of a confined liquid and presence of certain transitions at lower temperatures, which could be detected only for cooling regime. The localization of confined water in the partially filled pores of CPG at room temperature was studied.

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

    NASA Astrophysics Data System (ADS)

    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

  11. Energetics of anhydrite, barite, celestine, and anglesite: a high-temperature and differential scanning calorimetry study

    NASA Astrophysics Data System (ADS)

    Majzlan, J.; Navrotsky, A.; Neil, J. M.

    2002-05-01

    The thermochemistry of anhydrous sulfates (anglesite, anhydrite, arcanite, barite, celestine) was investigated by high-temperature oxide melt calorimetry and differential scanning calorimetry. Complete retention and uniform speciation of sulfur in the solvent was documented by (a) chemical analyses of the solvent (3Na 2O · 4MoO 3) with dissolved sulfates, (b) Fourier transform infrared spectroscopy confirming the absence of sulfur species in the gases above the solvent, and (c) consistency of experimental determination of the enthalpy of drop solution of SO 3 in the solvent. Thus, the principal conclusion of this study is that high-temperature oxide melt calorimetry with 3Na 2O · 4MoO 3 solvent is a valid technique for measurement of enthalpies of formation of anhydrous sulfates. Enthalpies of formation (in kJ/mol) from the elements (ΔH fo) were determined for synthetic anhydrite (CaSO 4) (-1433.8 ± 3.2), celestine (SrSO 4) (-1452.1 ± 3.3), anglesite (PbSO 4) (-909.9 ± 3.4), and two natural barite (BaSO 4) samples (-1464.2 ± 3.7, -1464.9 ± 3.7). The heat capacity of anhydrite, barite, and celestine was measured between 245 and 1100 K, with low- and high-temperature Netzsch (DSC-404) differential scanning calorimeters. The results for each sample were fitted to a Haas-Fisher polynomial of the form C p(245 K < T < 1100 K) = a + bT + cT -2 + dT -0.5 + eT 2. The coefficients of the equation are as follows: for anhydrite a = 409.7, b = -1.764 × 10 -1, c = 2.672 × 10 6, d = -5.130 × 10 3, e = 8.460 × 10 -5; for barite, a = 230.5, b = -0.7395 × 10 -1, c = -1.170 × 10 6, d = -1.587 × 10 3, e = 4.784 × 10 -5; and for celestine, a = 82.1, b = 0.8831 × 10 -1, c = -1.213 × 10 6, d = 0.1890 × 10 3, e = -1.449 × 10 -5. The 95% confidence interval of the measured C p varies from 1 to 2% of the measured value at low temperature up to 2 to 5% at high temperature. The measured thermochemical data improve or augment the thermodynamic database for anhydrous

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

    PubMed

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

    2011-01-01

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

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

    PubMed Central

    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.

    2011-01-01

    SUMMARY 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. PMID:21504829

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

    PubMed

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

    2016-02-01

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

  15. New approach to study starch gelatinization applying a combination of hot-stage light microscopy and differential scanning calorimetry.

    PubMed

    Li, Qian; Xie, Qin; Yu, Shujuan; Gao, Qunyu

    2013-02-13

    To overcome the difficulty of the original polarizing microscope-based method in monitoring the gelatinization of starch, a new method for dynamically monitoring the gelatinization process, integral optical density (IOD), which was based on the digital image analysis technique, was proposed. Hot-stage light microscopy and differential scanning calorimetry (DSC) techniques were coupled to study the dynamic changes of three types of starches: type A (corn starch), type B (potato starch), and type C (pea starch), during the gelatinization process in an excess water system. A model of response difference change of crystallite could represent the responding intensity of crystallization changes in the process of starch gelatinization. Results demonstrated that three crystalline types of starch underwent a process of swelling, accompanied with gradual disappearing of the crystallite. This difference was mainly associated with the diversity and composition of the starch structure. The IOD method was of advantage compared to the previous traditional methods that are based on a polarization microscope, such as counting the particle number and calculating polarization area methods, because it was the product of two parameters: optical density and area, which would be a response of both light intensity and area of birefringence light. The single peak in DSC corresponded to the combination of crystalline helix-helix dissociation and the reduction of the molecule helix-coil transition, while the gelatinization degree measured by the IOD method mainly corresponded to the helix-helix dissociation. The gelatinization mechanism could be revealed clearer in this study. PMID:23339369

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

    PubMed

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

    2016-03-01

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

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

    SciTech Connect

    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 %C2%B0C very little oxidation took place; at 850 %C2%B0C oxidation occurred after an induction period, while at 950 %C2%B0C oxidation occurred without an induction period. At oxidation temperatures between 1050 and 1150 %C2%B0C rapid passivation of the surface of the aluminum foil occurred, while at 1250 %C2%B0C 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.

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

    NASA Astrophysics Data System (ADS)

    Faruque, Sk Abdul Kader Md; Ranjan Bhattachryya, Satya; Sinha, Anil Kumar; Chakraborty, Supratic

    2016-02-01

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

  19. Insights into composition/structure/function relationships of Doxil® gained from "high-sensitivity" differential scanning calorimetry.

    PubMed

    Wei, Xiaohui; Cohen, Rivka; Barenholz, Yechezkel

    2016-07-01

    Thermotropic behavior of Doxil® and its generic, Lipodox®, was characterized using "high-sensitivity" differential scanning calorimetry (DSC). This is the first report that two distinct endotherms were observed in Doxil and Lipodox upon heating. The first (Tm at 51±2°C) is broad and of low enthalpy, representing the membrane lipid phase transition, which occurs despite having high (38mole%) cholesterol. The second (Tm at ∼70°C) is narrow, representing melting of the intraliposomal doxorubicin-sulfate nanocrystals. The thermograms of Doxil and Lipodox are practically identical. The membrane phase transition is similar to that of drug-free nanoliposomes of the same size and lipid composition as Doxil, suggesting lack of significant drug-membrane interaction. The melting endotherm of the intraliposomal nanocrystals is 2.0-2.5-fold narrower than that of the crystals formed in a solution of 250mM ammonium sulfate and >60mg/ml doxorubicin. This suggests that nanovolume of liposomes improves doxorubicin-sulfate crystallinity. Moreover, both phase transitions are reversible in cycled DSC scanning (15-90-15°C). This indicates an unexpected "non-leaky" phospholipid phase transition and excellent physical and chemical stabilities of Doxil after short exposure to high temperature. Reducing mole% of cholesterol results in a "leaky" membrane phase transition of higher enthalpy. Namely, high mole% cholesterol is essential for the resistance to drug leakage during phase transition. Pegylated liposomal doxorubicin in which HSPC was replaced by DPPC shows the same non-leaky phase transition but at a lower temperature, indicating this type of phase transition is not unique to Doxil. The presence of DSPE-PEG2k increases the cooperativity of the phase transition. High-sensitivity DSC helps illuminate composition/structure/function relationships of Doxil, and is useful for the equivalence/similarity studies. PMID:27106607

  20. CALOR2012 XVth International Conference on Calorimetry in High Energy Physics

    SciTech Connect

    Akchurin, Nural .

    2015-05-04

    The International Conferences on Calorimetry in High Energy Physics, or the CALOR series, have always been where the calorimeter experts come together to review the state of calorimetry and bring forth new ideas every two years. The fteenth conference, CALOR2012, in Santa Fe was no exception. Although they were built roughly a decade ago, we are now witnessing the exceptional power of the LHC calorimeters and the crucial role they have been playing in the discovery of the 125 GeV Higgs-like boson. As we ruminate on the coming generation of experiments at the next (linear) collider and on the upgrades at the LHC, we are heartened by the substantial advances we made in calorimetry in the last decade. These advances will certainly help uncover new physics in the years to come, not only at colliders but also in astroparticle experiments that take advantage of natural elements such as air, water, and ice. The proceedings were published by the IOP in Journal of Physics, Vol 404 2011. The conference web site is calor2012.ttu.edu.

  1. The Drosophila Sodium Channel 1 (DSC1): The founding member of a new family of voltage-gated cation channels.

    PubMed

    Dong, Ke; Du, Yuzhe; Rinkevich, Frank; Wang, Lingxin; Xu, Peng

    2015-05-01

    It has been nearly three decades since the identification of the Drosophila Sodium Channel 1 (DSC1) gene from Drosophila melanogaster. The orthologs of the DSC1 gene have now been identified in other insect species including BSC1 from Blattella germanica. Functional analyses of DSC1/BSC1 channels in Xenopus oocytes reveal that DSC1 and BSC1 encode voltage-gated cation channels that are more permeable to Ca(2+) than to Na(+). Genetic and electrophysiological analyses show that knockout of the DSC1 gene in D. melanogaster causes behavioral and neurological modifications. In this review, we summarize major findings from recent studies and highlight a unique role of the DSC1 channel, distinct from that of the sodium channel, in regulating membrane excitability and modulating toxicity of pyrethroid insecticides. PMID:25987218

  2. Multispectral Image Compression Based on DSC Combined with CCSDS-IDC

    PubMed Central

    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. PMID:25110741

  3. Determining the main thermodynamic parameters of caffeine melting by means of DSC

    NASA Astrophysics Data System (ADS)

    Agafonova, E. V.; Moshchenskii, Yu. V.; Tkachenko, M. L.

    2012-06-01

    The temperature and enthalpy of the melting of caffeine, which are 235.5 ± 0.1°C and 19.6 ± 0.2 kJ/mol, respectively, are determined by DSC. The melting entropy and the cryoscopic constant of caffeine are calculated.

  4. ESTIMATION OF HRW WHEAT HEAT DAMAGE BY DSC, CAPILLARY ZONE ELECTROPHORESIS, PHOTOACOUSTIC SPECTROSCOPY AND RHEOMETRY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of heat damage was estimated using Hard Red Winter (HRW) wheat varieties grown in Oklahoma. The testing was done on wheat kernels, flour, and isolated starch. Whole-wheat kernels were analyzed by Photoacoustic Spectroscopy (PAS). Flour was analyzed by DSC, Capillary Electrophoresis (CE...

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

    PubMed

    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. PMID:25687544

  6. Calorimetry measurements in less than 20 minutes

    NASA Astrophysics Data System (ADS)

    Perry, R. B.; Cremers, T.

    Argonne National Laboratory has developed a new series of 10 watt Bulk Plutonium Assay Calorimeters (BPAC10). The calorimeter measures bulk samples of plutonium bearing material in containers up to 5 in. in diameter and 7 in. high. The average measurement time is 19.7 minutes compared to 2-9 hours for the same sample measured in a water bath calorimeter. Measurement precision in the range of 1-10 watts is 1 to 0.1 percent and it is 0.010 watt for sample power less than 1 watt. The BPAC10 series calorimeters are in use in two plutonium facilities at the EG&G Rocky Flats Plant and at the Los Alamos National Laboratory TA55 Plutonium Facility. The paper presents a description of the calorimeter, discusses operating experience at Los Alamos, and presents a comparison of data on typical samples measured with both types of calorimeters.

  7. Warm-up calorimetry of Dewar-Detector Assemblies

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  8. Isothermal Titration Calorimetry Can Provide Critical Thinking Opportunities

    ERIC Educational Resources Information Center

    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…

  9. Preparation of Solid Derivatives by Differential Scanning Calorimetry.

    ERIC Educational Resources Information Center

    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…

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  11. New detecting techniques for a future calorimetry

    NASA Astrophysics Data System (ADS)

    Auffray, E.; Buganov, O.; Fedorov, A.; Korjik, M.; Lecoq, P.; Tamulaitis, G.; Tikhomirov, S.; Vasil'ev, A.

    2015-02-01

    In the last forty years, application of crystalline materials in homogeneous Electromagnetic Calorimeters has played a crucial role in the discovery of matter properties and promoted a continuous progress in the detecting technique. The detection systems progressed from small detectors based on NaI(Tl), CsI(Na), BaF2, PbF2, and Bi4Ge3O12 to giant Electromagnetic Calorimeters of CMS, ALICE Collaborations at LHC and PANDA Collaboration at FAIR, where the systems consisted of thousands lead tungstate PbWO4 scintillation crystals. Lead tungstate (PWO) became the most extensively used scintillation material in high energy physics experiments. PWO possesses a unique combination of scintillation properties including high energy and time resolutions in the detection of high energy particles. Here, we report on the results of the two photon absorption in PWO crystals obtained by pump-probe technique using ultra short laser pulses. The results demonstrate that the relaxation processes in PWO offer capability of this material to be used in detection systems to make a time stamp with precision close to 10-12 s or even better.

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

    PubMed

    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. PMID:25461814

  13. Using Isothermal Titration Calorimetry to Determine Thermodynamic Parameters of Protein–Glycosaminoglycan Interactions

    PubMed Central

    Dutta, Amit K.; Rösgen, Jörg; Rajarathnam, Krishna

    2015-01-01

    It has now become increasingly clear that a complete atomic description of how biomacromolecules recognize each other requires knowledge not only of the structures of the complexes but also of how kinetics and thermodynamics drive the binding process. In particular, such knowledge is lacking for protein–glycosaminoglycan (GAG) complexes. Isothermal titration calorimetry (ITC) is the only technique that can provide various thermodynamic parameters—enthalpy, entropy, free energy (binding constant), and stoichiometry—from a single experiment. Here we describe different factors that must be taken into consideration in carrying out ITC titrations to obtain meaningful thermodynamic data of protein–GAG interactions. PMID:25325962

  14. Estimation of Temperature Range for Cryo Cutting of Frozen Mackerel using DSC

    NASA Astrophysics Data System (ADS)

    Okamoto, Kiyoshi; Hagura, Yoshio; Suzuki, Kanichi

    Frozen mackerel flesh was subjected to measurement of its fracture stress (bending energy) in a low temperature range. The optimum conditions for low temperature cutting, "cryo cutting," were estimated from the results of enthalpy changes measured by a differential scanning calorimeter (DSC). There were two enthalpy changes for gross transition on the DSC chart for mackerel, one was at -63°C to -77°C and the other at -96°C to -112°C. Thus we estimated that mackerel was able to cut by bending below -63°C and that there would be a great decrease in bending energy occurring at around -77°C and -112°C. In testing, there were indeed two great decreases of bending energy for the test pieces of mackerel that had been frozen at -40°C, one was at -70°C to -90°C and the other was at -100°C to -120°C. Therefore, the test pieces of mackerel could be cut by bending at -70°C. The results showed that the DSC measurement of mackerel flesh gave a good estimation of the appropriate cutting temperature of mackerel.

  15. Apolipophorin III interaction with model membranes composed of phosphatidylcholine and sphingomyelin using differential scanning calorimetry.

    PubMed

    Chiu, Michael H; Wan, Chung-Ping Leon; Weers, Paul M M; Prenner, Elmar J

    2009-10-01

    Apolipophorin III (apoLp-III) from Locusta migratoria was employed as a model apolipoprotein to gain insight into binding interactions with lipid vesicles. Differential scanning calorimetry (DSC) was used to measure the binding interaction of apoLp-III with liposomes composed of mixtures of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and sphingomyelin (SM). Association of apoLp-III with multilamellar liposomes occurred over a temperature range around the liquid crystalline phase transition (L(alpha)). Qualitative and quantitative data were obtained from changes in the lipid phase transition upon addition of apoLp-III. Eleven ratios of DMPC and SM were tested from pure DMPC to pure SM. Broadness of the phase transition (T(1/2)), melting temperature of the phase transition (T(m)) and enthalpy were used to determine the relative binding affinity to the liposomes. Multilamellar vesicles composed of 40% DMPC and 60% SM showed the greatest interaction with apoLp-III, indicated by large T(1/2) values. Pure DMPC showed the weakest interaction and liposomes with lower percentage of DMPC retained domains of pure DMPC, even upon apoLp-III binding indicating demixing of liposome lipids. Addition of apoLp-III to rehydrated liposomes was compared to codissolved trials, in which lipids were rehydrated in the presence of protein, forcing the protein to interact with the lipid system. Similar trends between the codissolved and non-codissolved trials were observed, indicating a similar binding affinity except for pure DMPC. These results suggested that surface defects due to non-ideal packing that occur at the phase transition temperature of the lipid mixtures are responsible for apolipoprotein-lipid interaction in DMPC/SM liposomes. PMID:19647717

  16. Differential Scanning Calorimetry and Evolved Gas Analysis of Hydromagnesite

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

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

  17. Inherent limitations of fixed time servo-controlled radiometric calorimetry

    SciTech Connect

    Wetzel, J.R.; Duff, M.F.; Lemming, J.F.

    1987-01-01

    There has been some interest in low precision, short run time calorimetry measurements. This type of calorimetry measurement has been proposed for use when high precision measurements are not required, for example, to screen scrap containers to determine if there is enough material to be measured more accurately of for confirmatory measurements that only require low precision results. The equipment needed to make these measurements is a servo-controlled calorimeter with a sample preequilibration bath. The preequilibration bath temperature is set to the internal temperature of the calorimeter running at a fixed servo-controlled wattage level. The sample power value is determined at a fixed time form the sample loading into the calorimeter. There are some limitations and areas of uncertainties in the use of data obtained by this method. Data collected under controlled conditions demonstrate the limitations. Sample packaging, preequilibration time, and item wattage were chosen as the variables most likely to be encountered in a plant environment.

  18. Assessment of the Dissociation Energetics of Some Selected Ligand Drugs Bound on Human Serum Albumin by Differential Scanning Calorimetry.

    PubMed

    Faroongsarng, Damrongsak

    2016-04-01

    Drug-protein binding may play a role in the thermal energetics of protein denaturation and could lead to the determination of its equilibrium dissociation parameter. The aim of this study was to assess the energetics of a drug that was bound to human serum albumin (HSA) during thermal denaturation. Drugs that were bound at a single high-affinity primary binding site on HSA, including diazepam and ibuprofen, were employed. Commercial HSA was treated with charcoal to remove stabilizers and adjusted to 20% w/v in a pH 7.4 buffered solution. Serial concentrations of individual drugs up to 0.16 mmole/g-protein were added to the cleaned HSA solutions whereas diazepam was added to a commercial HSA solution. Samples were subjected to differential scanning calorimetry (DSC) set to run from 37 to 90°C at 3.0°C/min. Binding of the drug slightly increased the denaturing temperature of the cleaned HSA due to a shift in the equilibrium toward the native protein bound with the drug. Diazepam depressed the denaturing temperature of the commercial HSA by competing with the stabilizers already bound to the primary site of the HSA. This yielded not only the HSA-stabilizer but also the HSA-diazepam type complexes that exhibited a different denaturation process. A rational approximation of the Lumry-Eyring protein denaturation model was used to treat the DSC endotherms. The approximated scheme: [Formula: see text] was successfully fitted to the data. It was used to determine the dissociation parameters for diazepam and ibuprofen bound to the HSA. These results were comparable to those obtained from other methods. PMID:26246411

  19. Applications of differential scanning calorimetry in developing cryopreservation strategies for Parkia speciosa, a tropical tree producing recalcitrant seeds.

    PubMed

    Nadarajan, Jayanthi; Mansor, Marzalina; Krishnapillay, Baskaran; Staines, Harry J; Benson, Erica E; Harding, Keith

    2008-01-01

    Shoot-tips of Parkia speciosa, a recalcitrant seed producing tropical leguminous tree withstood cryopreservation using encapsulation-vitrification in combination with trehalose preculture. Differential scanning calorimetry (DSC) revealed that trehalose moderated the thermal characteristics of the shoot-tips. A 30 min PVS2 treatment had the lowest glass transition temperature (Tg) (-50.2 +/- 1.1 degree C) when applied in combination with 5% (w/v) trehalose. The Tg increased to -40.2 +/- 1.0 degree C as the sugar concentration was decreased to 2.5 percent (w/v). Tg heat capacity for shoot-tips treated with 2.5 percent and 5 percent (w/v) trehalose and exposed to PVS2 for 30 min increased from 0.17 +/ 0.05 to 0.23 +/- 0.01 J per gram, respectively. Enthalpies of the melt-endotherm varied in proportion to trehalose concentration, for the 30 min PVS2 treatment, whereas the melt enthalpy for control shoots was greater than 150 J per gram and decreased to ca. 60 J per gram with 2.5 percent (w/v) trehalose. For 5 percent and 10 percent (w/v) trehalose treatments, enthalpy declined to ca. 24 and 12 J per gram respectively and freezing points were depressed to -75 degree C and -85 degree C with 2.5 percent and 5 percent trehalose (w/v), respectively. DSC elucidated the critical points at which vitrification occurred in germplasm exposed to trehalose and PVS2. A 60 min PVS2 treatment supporting ca. 70 percent survival was found optimal for stable glass formation during cooling and on rewarming. PMID:18516340

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

    SciTech Connect

    Wai, Y.C.; Labov, S.E.; Silver, E.H.

    1990-08-13

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

  1. The Philosophy and Feasibility of Dual Readout Calorimetry

    SciTech Connect

    Hauptman, John

    2006-10-27

    I will discuss the general physical ideas behind dual-readout calorimetry, their implementation in DREAM (Dual REAdout Module) with exact separation of scintillation and Cerenkov light, implementation with mixed light in DREAM fibers, anticipated implementation in PbWO4 crystals with applications to the 4th Concept detector and to CMS, use in high energy gamma-ray and cosmic ray astrophysics with Cerenkov and N2 fluorescent light, and implementation in the 4th Concept detector for muon identification.

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

    PubMed

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

    2016-01-01

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

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

    PubMed

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

    2015-12-01

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

  4. The states of water within poly(vinyl alcohol) thin films part 2: Investigation by differential scanning calorimetry and thermogravimetric analysis

    SciTech Connect

    Hodge, R.M.; Edward, G.H.; Simon, G.P.

    1993-12-31

    In order to utilize thermoplastic processing techniques with poly(vinyl alcohol) (PVA), the polymer must be plasticized with water. Water exists in different states within the PVA network and behaves in a manner specific to each state. This work uses Differential Scanning Calorimetry (DSC) and Thermo-Gravimetric Analysis to investigate the nature of water within PVA thin films. A model is proposed whereby the ingression of each state of water to exist in 3 distinct states: (1) free of bulk water, (2) freezable bound (loosely bound) water, and (3) nonfreezable bound (strongly bound) water. Generally speaking, the data suggest that the various states of water are filled sequentially. The model is consistent with the results of Positron Annihilation Lifetime Spectroscopy (PALS), also to be presented at this conference.

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

    NASA Astrophysics Data System (ADS)

    Saini, Manoj K.

    2015-06-01

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

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

    SciTech Connect

    Fernandez, Jose M.; Plaza, Cesar; Polo, Alfredo; Plante, Alain F.

    2012-01-15

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

  7. Estimation of the nucleation rate by differential scanning calorimetry

    NASA Technical Reports Server (NTRS)

    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.

  8. Increased efficiency of DSC coupled to one-dimensional photonic crystals

    NASA Astrophysics Data System (ADS)

    Colodrero, Silvia; Míguez, Hernán

    2010-05-01

    The optimization of the conversion efficiency of dye sensitized solar cells (DSC) has become a key issue nowadays due to the search for alternative energy resources. Different approaches based on the optical absorption enhancement can be realized in this type of solar devices by modifying the optical design of the cell. In this respect, novel porous and highly reflecting one-dimensional photonic crystals (1DPC) have been recently implemented in DSC due to their great potential for the manipulation of light propagation. The periodic structure is built by alternating layers made of different types of nanoparticles that allow us to obtain a wide and intense Bragg reflection peak. The photonic crystal, with a thickness of just half-micron, is able to efficiently localize incident light within the nc-dyed TiO2 electrode in a targeted wavelength range. So, significant optical absorption amplification in a wide spectral range occurs in these structures that combine the presence of a highly reflecting photonic crystal and a layer of absorbing material, being therefore enhanced the photogenerated current. Average power conversion efficiencies are improved between 15% and 30% with respect to the reference value attained for standard electrodes with no photonic crystal coupled.

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

    PubMed Central

    Zeng, Xiangkai; Zhu, Zhixiong; Chen, Yang

    2016-01-01

    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. PMID:27120607

  10. PREFACE: 16th International Conference on Calorimetry in High Energy Physics (CALOR 2014)

    NASA Astrophysics Data System (ADS)

    Novotny, Rainer W.

    2015-02-01

    The XVIth International Conference on Calorimetry in High Energy Physics - CALOR 2014 - was held in Giessen, Germany from 6-11 April 2014 at the Science Campus of the University. It was hosted by the Justus-Liebig-University and the HIC for FAIR Helmholtz International Center. The series of conferences on calorimetry were started in 1990 at Fermilab and are focusing primarily on operating and future calorimeter systems within the Hadron and High-Energy Physics community without neglecting the impact on other fields such as Astrophysics or Medical Imaging. Confirmed by the impressive list of over 70 oral presentations, 5 posters and over 100 attendees, the field of calorimetry appears alive and attractive. The present volume contains the written contributions of almost all presentations which can be found at http://calor2014.de. Time slots of 15 or 30 minutes including discussion were allocated. The conference was accompanied by a small exhibition of several industrial companies related to the field. The day before the opening of the scientific program, Richard Wigmans gave an excellent and vivid tutorial on basic aspects on calorimetry meant as an introduction for students and conference attendees new in the field. The opening ceremony was used to give an impression of the present and future status and the scientific program of the new FAIR facility nearby at Darmstadt presented by Klaus Peters from GSI. The conference program of the first day was dedicated to the performance and required future upgrade of the LHC experiments, dominated by ATLAS, CMS and LHCb. The program of the next day contained specific aspects on electronics and readout as well as calorimetry in outer space. Several contributions discussed in detail new concepts for hadron calorimeters within the CALICE collaboration completed by a session on sampling calorimeters. The next sections were dedicated to operating and future calorimeters at various laboratories and covering a wide range of

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

    PubMed

    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. PMID:25602591

  12. Bridging Calorimetry and Simulation through Precise Calculations of Cucurbituril–Guest Binding Enthalpies

    PubMed Central

    2015-01-01

    We used microsecond time scale molecular dynamics simulations to compute, at high precision, binding enthalpies for cucurbit[7]uril (CB7) with eight guests in aqueous solution. The results correlate well with experimental data from previously published isothermal titration calorimetry studies, and decomposition of the computed binding enthalpies by interaction type provides plausible mechanistic insights. Thus, dispersion interactions appear to play a key role in stabilizing these complexes, due at least in part to the fact that their packing density is greater than that of water. On the other hand, strongly favorable Coulombic interactions between the host and guests are compensated by unfavorable solvent contributions, leaving relatively modest electrostatic contributions to the binding enthalpies. The better steric fit of the aliphatic guests into the circular host appears to explain why their binding enthalpies tend to be more favorable than those of the more planar aromatic guests. The present calculations also bear on the validity of the simulation force field. Somewhat unexpectedly, the TIP3P water yields better agreement with experiment than the TIP4P-Ew water model, although the latter is known to replicate the properties of pure water more accurately. More broadly, the present results demonstrate the potential for computational calorimetry to provide atomistic explanations for thermodynamic observations. PMID:25221445

  13. A new approach for non-contact calorimetry: system identification using pseudo-white noise perturbation

    NASA Astrophysics Data System (ADS)

    Schetelat, Pascal; Etay, Jacqueline

    2011-07-01

    This paper presents a new technique for non-contact calorimetry measurement of specific heat capacity and thermal conductivity. Based on pseudo-white noise modulation and system identification, commonly used in electronics and communication engineering, this procedure can be used to measure the transfer function of the sample temperature variation due to heating power variation. The heat capacity and internal heat transfer coefficient are then determined using the equivalence between the identified transfer functions of the temperatures measured at two locations and the analytical model proposed by Fecht and Johnson (Rev Sci Instrum 62:1299-1303, 1991) and Wunderlich and Fecht (Measur Sci Technol 16:402-416, 2005). This inverse problem is solved numerically using a Gauss-Seidel algorithm. A numerical simulation of a non-contact modulated calorimetry experiment is used to demonstrate the relevance of this new technique for indirect measurement of the heat capacity and heat transfer coefficients of solid samples presenting large Biot numbers ( Bi > 0.4).

  14. Water Calorimetry: A Correction to the Heat Defect Calculations

    PubMed Central

    Klassen, Norman V.; Ross, Carl K.

    2002-01-01

    In a recent publication, we used a reaction model (model III) to calculate the heat defect for the irradiation of aqueous solutions with ionizing radiation at 21 °C. Subsequent work has revealed that the literature value used for one of the rate constants in the model was incorrect. A revised model (model IIIR) incorporates the correct rate constant for 21 °C. Versions of models III and IIIR were created for irradiations at 4 °C. For our current water calorimetry protocol, the values of the heat defect for H2/O2-water (water saturated with a flow of 43 % H2 and 57 % O2, by volume) at 21 °C predicted by model III and model IIIR are similar but the value for 4 °C predicted by III is 30 % smaller than the value predicted by IIIR. Model IIIR predicts that the values of the heat defect at 21 °C and 4 °C lie within the range −0.023±0.002, in agreement with the values obtained from our water calorimetry measurements done using pure water and H2-saturated water at 21 °C and 4 °C. The yields of hydrogen peroxide in H2/O2-water at 21 °C and 4 °C were measured and agree with the predictions of model IIIR. Our water calorimetry measurements made with pure water and H2-saturated water are now of sufficient quality that they can be used to determine the heat defect for H2/O2-water better than can be done by simulations. However, consistency between the three systems continues to be an excellent check on water purity which is crucial, especially for the pure water system.

  15. A Serious Game for Massive Training and Assessment of French Soldiers Involved in Forward Combat Casualty Care (3D-SC1): Development and Deployment

    PubMed Central

    Mérat, Stéphane; Malgras, Brice; Petit, Ludovic; Queran, Xavier; Bay, Christian; Boutonnet, Mathieu; Jault, Patrick; Ausset, Sylvain; Auroy, Yves; Perez, Jean Paul; Tesnière, Antoine; Pons, François; Mignon, Alexandre

    2016-01-01

    Background The French Military Health Service has standardized its military prehospital care policy in a ‘‘Sauvetage au Combat’’ (SC) program (Forward Combat Casualty Care). A major part of the SC training program relies on simulations, which are challenging and costly when dealing with more than 80,000 soldiers. In 2014, the French Military Health Service decided to develop and deploy 3D-SC1, a serious game (SG) intended to train and assess soldiers managing the early steps of SC. Objectives The purpose of this paper is to describe the creation and production of 3D-SC1 and to present its deployment. Methods A group of 10 experts and the Paris Descartes University Medical Simulation Department spin-off, Medusims, coproduced 3D-SC1. Medusims are virtual medical experiences using 3D real-time videogame technology (creation of an environment and avatars in different scenarios) designed for educational purposes (training and assessment) to simulate medical situations. These virtual situations have been created based on real cases and tested on mannequins by experts. Trainees are asked to manage specific situations according to best practices recommended by SC, and receive a score and a personalized feedback regarding their performance. Results The scenario simulated in the SG is an attack on a patrol of 3 soldiers with an improvised explosive device explosion as a result of which one soldier dies, one soldier is slightly stunned, and the third soldier experiences a leg amputation and other injuries. This scenario was first tested with mannequins in military simulation centers, before being transformed into a virtual 3D real-time scenario using a multi-support, multi–operating system platform, Unity. Processes of gamification and scoring were applied, with 2 levels of difficulty. A personalized debriefing was integrated at the end of the simulations. The design and production of the SG took 9 months. The deployment, performed in 3 months, has reached 84 of 96

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

    PubMed

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

    2017-01-01

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

  17. The use of calorimetry in nuclear materials management

    SciTech Connect

    Nutter, J.D.; O`Hara, F.A.; Rodenburg, W.W.

    1996-07-01

    A calorimeter is a device to measure evolved or adsorbed heat. For our purposes, the heat measured is that associated with radioactive decay and the unit of measurement is the watt. Each time an atom decays, energy is released and absorbed by the surroundings and heat generated. For each isotope, this heat is a constant related to the energy of the decay particles and the half-life of the isotope. A point which is often overlooked is that calorimetry is one of the oldest techniques known for measuring radioactivity. In 1903, Pierre Curie and A. Laborde used a twin microcalorimeter to determine that one gram of radium generates about 100 calories per hour. Several months later, Curie and Dewar used liquid oxygen and hydrogen to show that the amount of energy developed by radium and other radioactive elements did not depend on temperature. At that time, this observation was extremely important. It indicated that the nature of radioactivity is entirely different and cannot be compared with any known phenomena. In all other thermal processes known in physics and chemistry, the rate at which heat is developed changes with temperature. In 1942, Monsanto was asked by General Leslie Groves, Head of the Manhattan Project, to accept the responsibility for the chemistry and metallurgy of radioactive polonium. Late in 1943, two Monsanto scientists began a study of the half-life of polonium-210 using calorimetry.

  18. The Pandora Software Development Kit for Particle Flow Calorimetry

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    Pandora is a robust and efficient framework for developing and running pattern-recognition algorithms. It was designed to perform particle flow calorimetry, which requires many complex pattern-recognition techniques to reconstruct the paths of individual particles through fine granularity detectors. The Pandora C++ software development kit (SDK) consists of a single library and a number of carefully designed application programming interfaces (APIs). A client application can use the Pandora APIs to pass details of tracks and hits/cells to the Pandora framework, which then creates and manages named lists of self-describing objects. These objects can be accessed by Pandora algorithms, which perform the pattern-recognition reconstruction. Development with the Pandora SDK promotes the creation of small, re-usable algorithms containing just the kernel of a specific operation. The algorithms are configured via XML and can be nested to perform complex reconstruction tasks. As the algorithms only access the Pandora objects in a controlled manner, via the APIs, the framework can perform most book-keeping and memory-management operations. The Pandora SDK has been fully exploited in the implementation of PandoraPFA, which uses over 60 algorithms to provide the state of the art in particle flow calorimetry for ILC and CLIC.

  19. Heat capacity of alkanolamines by differential scanning calorimetry

    SciTech Connect

    Chiu, L.F.; Liu, H.F.; Li, M.H.

    1999-05-01

    Measurements of the heat capacities of the alkanolamines monoethanolamine, diethanolamine, diglycolamine, di-2-propanolamine, triethanolamine, N-methyldiethanolamine, 2-amino-2-methyl-l-propanol, and 2-piperidineethanol were performed from 30 to 80 C with a differential scanning calorimeter (DSC). The heat capacity of liquid water has been measured to verify the validity of the C{sub p} measurements. The measured C{sub p} of each alkanolamine has been expressed as a function of temperature. The estimated uncertainty of the measured heat capacities including the effect of impurities in a substance with a purity of 95% is {+-}3%. The measured heat capacities are, in general, of sufficient accuracy for most engineering-design calculations.

  20. Detectors for Linear Colliders: Calorimetry at a Future Electron-Positron Collider (3/4)

    SciTech Connect

    2010-02-17

    Calorimetry will play a central role in determining the physics reach at a future e+e- collider. The requirements for calorimetry place the emphasis on achieving an excellent jet energy resolution. The currently favoured option for calorimetry at a future e+e- collider is the concept of high granularity particle flow calorimetry. Here granularity and a high pattern recognition capability is more important than the single particle calorimetric response. In this lecture I will describe the recent progress in understanding the reach of high granularity particle flow calorimetry and the related R&D; efforts which concentrate on test beam demonstrations of the technological options for highly granular calorimeters. I will also discuss alternatives to particle flow, for example the technique of dual readout calorimetry.

  1. Detectors for Linear Colliders: Calorimetry at a Future Electron-Positron Collider (3/4)

    ScienceCinema

    None

    2011-10-06

    Calorimetry will play a central role in determining the physics reach at a future e+e- collider. The requirements for calorimetry place the emphasis on achieving an excellent jet energy resolution. The currently favoured option for calorimetry at a future e+e- collider is the concept of high granularity particle flow calorimetry. Here granularity and a high pattern recognition capability is more important than the single particle calorimetric response. In this lecture I will describe the recent progress in understanding the reach of high granularity particle flow calorimetry and the related R&D; efforts which concentrate on test beam demonstrations of the technological options for highly granular calorimeters. I will also discuss alternatives to particle flow, for example the technique of dual readout calorimetry.

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

    NASA Astrophysics Data System (ADS)

    Hirakawa, Satoru; Morimoto, Yoshiaki; Honda, Hisashi

    2015-04-01

    Electrical conductivity ( σ), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) measurements of n-C x H (2 x+1) OSO 3Li ( x= 12, 14, 16, 18, and 20) crystals were performed as a function of temperature. In addition, σ, DSC, and XRD observations of n-C x H (2 x+1) OSO 3Na and n-C x H (2 x+1) OSO 3K ( x= 12, 14, 16, 18, and 20) crystals were carried out for comparison. DSC results of the salts revealed several solid-solid phase transitions with large entropy changes (Δ S). For n-C 18 H 37 OSO 3Li and n-C 20 H 41 OSO 3Li salts, each melting point produced a small Δ S mp value compared with the total entropy change in the solid phases (Δ S tr1+Δ S tr2). Additionally, Li + ion diffusion was detected in the highest temperature solid phases. For K salts, larger σ values were detected for potassium alkylsulfates compared with those reported for alkyl carboxylate. 7Li NMR spectra of n-C 18 H 37 OSO 3Li crystals recorded in the low-temperature phase showed large asymmetry parameters, suggesting the Li + ions are localized at asymmetric sites in the crystals.

  3. Online particle detection with Neural Networks based on topological calorimetry information

    NASA Astrophysics Data System (ADS)

    Ciodaro, T.; Deva, D.; de Seixas, J. M.; Damazio, D.

    2012-06-01

    This paper presents the latest results from the Ringer algorithm, which is based on artificial neural networks for the electron identification at the online filtering system of the ATLAS particle detector, in the context of the LHC experiment at CERN. The algorithm performs topological feature extraction using the ATLAS calorimetry information (energy measurements). The extracted information is presented to a neural network classifier. Studies showed that the Ringer algorithm achieves high detection efficiency, while keeping the false alarm rate low. Optimizations, guided by detailed analysis, reduced the algorithm execution time by 59%. Also, the total memory necessary to store the Ringer algorithm information represents less than 6.2 percent of the total filtering system amount.

  4. Fast Scanning Calorimetry Studies of Supercooled Liquids and Glasses

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Deepanjan

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

  5. Measuring the Imaginary Part of the Permittivity Using Calorimetry

    NASA Astrophysics Data System (ADS)

    Kashuri, Hektor; Sigdel, Krishna; Kashuri, Klaida; Iannacchione, Germano S.

    2011-03-01

    Modulated or AC calorimetry is a well established technique for measuring the temperature dependence of the heat capacity of many complex fluids. Employing a dielectric or RF heating method, the heat capacity, thermal conductivity, and the dielectric properties of the sample are all probed simultaneously. Combining the results obtained by this technique for the liquid crystal 4-n-pentyl-4-cyanophenyl (5CB) with those obtained by our novel AC calorimetric technique employing RF (dielectric) heating, we have been able to directly measure the temperature dependence of the imaginary part of the permittivity of this liquid crystal. Measurements were performed over a temperature range from 303 to 313 K, spanning the nematic to isotropic phase transition, as well as radio frequencies from 10 to 30 MHz Worcester Polytechnic Institute (WPI).

  6. Isothermal titration calorimetry of ion-coupled membrane transporters

    PubMed Central

    SeCheol, Oh

    2015-01-01

    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. PMID:25676707

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

    PubMed

    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. PMID:18639378

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

    SciTech Connect

    Andrew Stroud, Lee Sawyer

    2012-08-31

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

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

    PubMed Central

    Kaiyala, Karl J.; Ramsay, Douglas S.

    2012-01-01

    Direct animal calorimetry, the gold standard method for quantifying animal heat production (HP), has been largely supplanted by respirometric indirect calorimetry owing to the relative ease and ready commercial availability of the latter technique. Direct calorimetry, however, can accurately quantify HP and thus metabolic rate (MR) in both metabolically normal and abnormal states, whereas respirometric indirect calorimetry relies on important assumptions that apparently have never been tested 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. PMID:20427023

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

    SciTech Connect

    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''.

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

    NASA Astrophysics Data System (ADS)

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

    2010-06-01

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

  12. Irreversible Thermal Denaturation of β-Hemocyanin of Helix pomatia and its Substructures Studied by Differential Scanning Calorimetry

    NASA Astrophysics Data System (ADS)

    Idakieva, Krassimira; Gielens, Constant; Siddiqui, Nurul I.; Doumanova, Lyubka; Vasseva, Boyka; Kostov, Georgi; Shnyrov, Valery L.

    2007-09-01

    The thermal denaturation of β -hemocyanin from the gastropod Helix pomatia (β -HpH) at neutral pH was studied by means of differential scanning calorimetry (DSC). The denaturation was completely irreversible as judged by the absence of any endotherm on rescanning previously scanned samples. Two transitions, with apparent transition temperatures (Tm) of ca. 84 °C (main transition) and ca. 88 °C (minor transition), were detected by DSC in 20 mM MOPS buffer, containing 0.1 M NaCl, 5mM CaCl2 and 5 mM MgCl2 at pH 7.2 (buffer A), using a heating rate of 1.0 Kmin-1. Both Tm values were dependent on the scanning rate, suggesting that the thermal denaturation of β -HpH is a kinetically controlled process. The Tm and specific enthalpy values (ΔHcal) for the thermal denaturation of β -HpH were found to be independent of the protein concentration, indicating that the dissociation of the protein into monomers does not take place before the rate-determining step of the process of thermal unfolding started. A successive annealing procedure was applied to obtain the experimental deconvolution of the irreversible thermal transitions. These transitions are tentatively attributed to the denaturation of, respectively, the wall (main transition) and the collar of the β -HpH molecule. The activation energies (EA) of both transitions were found to be similar (about 500 kJ mol-1). In 130 mM glycine/NaOH buffer, pH 9.6 (buffer B), with β -HpH dissociated into subunits, the calorimetric profile had a more complex character. This could be ascribed to a different stability of the functional units (FUs) constituting the β -HpH subunit. FU d, which in the cylindrical didecameric β -HpH molecule is located in the wall, was markedly less stable than FU g, which belongs to the collar. The thermal denaturation of FUs d and g was described by the two-state irreversible model. On the basis of this model, the parameters of the Arrhenius equation were calculated.

  13. Mobility and age of black carbon in two temperate grassland soils revealed by differential scanning calorimetry and radiocarbon dating

    NASA Astrophysics Data System (ADS)

    Leifeld, Jens; Feng, Xiaojuan; Eglinton, Timothy; Wacker, Lukas

    2015-04-01

    Black carbon (BC) is a natural component of soil organic matter (SOM) and abundant in many ecosystems. Its stability, due to its relative resistance to microbial decomposition, means it plays an important role in soil C sequestration. A recent review suggests that BC may be mobile in soil; hence, its contribution to a stable SOM pool may change over time due to its lateral or vertical reallocation (Rumpel et al. 2014). However, direct evidence of the mobility of BC, particularly with reference to its vertical mobility, is scarce. We studied the amount of BC in two temperate grassland fields (eutric clayey Camibsol,) that were established in 2001 on former cropland. Volumetric soil samples (0-50 cm, 5 cm increments) were taken at 10 spots in each field in 2001, 2006 and 2011. One of the fields was ploughed in 2007 and the sward was re-sown. BC content was measured by differential scanning calorimetry for a total number of c. 500 samples. The mean BC/OC ratio was 0.10 (±0.05) and reached 0.25 in some samples. Radiocarbon measurements from 24 bulk soil samples revealed relatively small 14C contents in 2001 (92±2.7 pMC) which increased over time (2006: 99.0±1.1 pMC; 2011: 99.1±1.1 pMC). Thermal fractionation of BC by DSC revealed calibrated BC ages of 400 to 1000 years (pMC 87-94), suggesting that BC originates from medieval and post-medieval fire clearings. The change in soil signature may have been caused by a preferential transport of old BC down the soil profile, leading to a selective enrichment of younger soil C over time. In line with this interpretation the DSC measurements suggest that in both fields, BC concentrations significantly decreased for most layers between 2001 and 2006. However, between 2006 and 2011, no further vertical reallocation was observed in the continuous grassland, whereas BC contents of the field ploughed in 2007 significantly increased in the top layers. Together, these data suggest that ploughing in 2001 triggered subsequent

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  15. DSC study of the isothermal crystallization of iPP-CNF nanocomposites

    NASA Astrophysics Data System (ADS)

    Chipara, Dorina M.; Chipara, Mircea

    2013-03-01

    Nanocomposite materials have been obtained by dispersing vapor grown carbon nanofibers (VGCNFs) with diameters ranging between 60 and 100 nm and lengths between 30,000 and 100,000 nm supplied by Pyrograf Products, Inc (PR-24AG) within a polymer matrix - isotactic polypropylene (iPP) - type Marlex HLN-120-01 with density 0.906 g/cm3 and melt flow rate at 230 oC of 12 g/10 min, supplied by Philips Sumika Polypropylene Company. VGCNFs have been purified and disentangled by reflux in dichloromethane and deionized water followed by vacuum filtering (for 24 h) and drying at 110 oC for 24h. The nanocomposites were obtained by melt mixing at 180 oC for 9 minutes with a speed of 65 rpm followed by an additional mixing at 90 rpm for 5 minutes, using a HAAKE Rheomix, Nanocomposites loaded with various amounts of VGCNFs (0%, 1%, 2.5%, 5%, 7.5%, 10%, 15%, and 20% wt.) have been prepared and investigated by TA DSC Q-500. Isothermal crystallization was investigated in detail and analyzed by using an expression derived from the Avrami equation. The effect of the filler on the isothermal crystallization of iPP is discussed in detail. The research is focused on the effect of VGCNF on the degree of crystallization of iPP, crystallization rate, and dimensionality of the crystallization process. This research has been supported by National Science Foundation under DMR. Contract grant number 0934157.

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

    NASA Astrophysics Data System (ADS)

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

    1997-03-01

    We have examined binary Ge_xSe_1-x glasses over a wide composition range 0 < x <0.34, using a TA Instruments Model 2920 MDSC. The glass transitions deduced from the heat flow increase monotonically with x or = 2(1+x), the average coordination number. The heat flow near Tg shows a rather striking threshold behavior (minimum) near x = 0.23, corresponding to the composition at which the glass network begins to abruptly stiffen as noted by an upshift in Raman mode frequencies(Xingwei Feng, et al., to be published.). The present observations suggest that the minimum in Cp change at Tg near the stiffness threshold, deduced from ordinary DSC(M. Tatsumisago, B.L. Halfpap, J.L. Green, S.M. Lindsay, and C.A. Angell, Phys. Rev. Lett. 64, 1549 (1990).), i.e., total heat flow, largely derives from the non-reversing component (relaxation related) heat flow near T_g.

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

    PubMed

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

    2007-04-11

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

  18. Reliable estimation of capillary transit time distributions using DSC-MRI

    PubMed Central

    Mouridsen, Kim; Hansen, Mikkel Bo; Østergaard, Leif; Jespersen, Sune Nørhøj

    2014-01-01

    The regional availability of oxygen in brain tissue is traditionally inferred from the magnitude of cerebral blood flow (CBF) and the concentration of oxygen in arterial blood. Measurements of CBF are therefore widely used in the localization of neuronal response to stimulation and in the evaluation of patients suspected of acute ischemic stroke or flow-limiting carotid stenosis. It was recently demonstrated that capillary transit time heterogeneity (CTH) limits maximum oxygen extraction fraction (OEFmax) that can be achieved for a given CBF. Here we present a statistical approach for determining CTH, mean transit time (MTT), and CBF using dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI). Using numerical simulations, we demonstrate that CTH, MTT, and OEFmax can be estimated with low bias and variance across a wide range of microvascular flow patterns, even at modest signal-to-noise ratios. Mean transit time estimated by singular value decomposition (SVD) deconvolution, however, is confounded by CTH. The proposed technique readily identifies malperfused tissue in acute stroke patients and appears to highlight information not detected by the standard SVD technique. We speculate that this technique permits the non-invasive detection of tissue with impaired oxygen delivery in neurologic disorders such as acute ischemic stroke and Alzheimer's disease during routine diagnostic imaging. PMID:24938401

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

    SciTech Connect

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

    2006-05-05

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

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

    NASA Astrophysics Data System (ADS)

    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

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

    PubMed

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

    2013-07-01

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

  2. Preliminary Analysis of the Social and Scientific Impact of the UAEM-ININ M.Sc. and D.Sc. Graduate Programme in Medical Physics

    NASA Astrophysics Data System (ADS)

    Mitsoura, Eleni; Isaac-Olive, Keila; Torres-Garcia, Eugenio; Camacho-Lopez, Miguel Angel; Hardy-Perez, Alberto

    2010-12-01

    Sponsored by the International Atomic Energy Agency (IAEA) in 1994, the Instituto Nacional de Investigaciones Nucleares (ININ) started in Mexico a teaching and training programme (Diplomado) in Radiotherapy Medical Physics. Based on this experience, the Universidad Autónoma del Estado de México (UAEM) and the Instituto Nacional de Investigaciones Nucleares (ININ) launched two years later, the first Graduate Programme in Science (M.Sc. and D.Sc.), specialised in Medical Physics in Mexico. A preliminary analysis of the social and scientific impact of the UAEM-ININ Programme is presented in this work based on the achievements attained, regarding the number of graduated Medical Physicists, their geographic and academic origin, their current professional activities and the number of scientific publications produced as a result of the thesis, as well as their citations.

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

    NASA Astrophysics Data System (ADS)

    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%.

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

    PubMed Central

    Sarpietro, Maria Grazia; Castelli, Francesco

    2011-01-01

    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. PMID:21430957

  5. Calorimetry by immersion into liquid nitrogen and liquid argon: a better way to determine the internal surface area of micropores.

    PubMed

    Navarrete, Ricardo; Llewellyn, Philip; Rouquerol, Françoise; Denoyel, Renaud; Rouquerol, Jean

    2004-09-15

    The aim of this work is to assess the internal surface area of a set of samples (either carbons or oxides, either porous or nonporous, either microporous or mesoporous) by microcalorimetry via immersion into liquid nitrogen or argon. We have made use of an isothermal, heat-flux microcalorimeter, initially designed and built in our laboratory for the sake of gas adsorption experiments at 77 or 87 K. It seems that immersion calorimetry into liquid nitrogen and argon makes it possible to go one step further in the determination of the internal surface area of micropores. PMID:15341849

  6. Explicit formulation of titration models for isothermal titration calorimetry.

    PubMed

    Poon, Gregory M K

    2010-05-15

    Isothermal titration calorimetry (ITC) produces a differential heat signal with respect to the total titrant concentration. This feature gives ITC excellent sensitivity for studying the thermodynamics of complex biomolecular interactions in solution. Currently, numerical methods for data fitting are based primarily on indirect approaches rooted in the usual practice of formulating biochemical models in terms of integrated variables. Here, a direct approach is presented wherein ITC models are formulated and solved as numerical initial value problems for data fitting and simulation purposes. To do so, the ITC signal is cast explicitly as a first-order ordinary differential equation (ODE) with total titrant concentration as independent variable and the concentration of a bound or free ligand species as dependent variable. This approach was applied to four ligand-receptor binding and homotropic dissociation models. Qualitative analysis of the explicit ODEs offers insights into the behavior of the models that would be inaccessible to indirect methods of analysis. Numerical ODEs are also highly compatible with regression analysis. Since solutions to numerical initial value problems are straightforward to implement on common computing platforms in the biochemical laboratory, this method is expected to facilitate the development of ITC models tailored to any experimental system of interest. PMID:20100451

  7. Calorimetry of deformed aluminum reinforced with alumina particles

    SciTech Connect

    Srichai, M.B.; Dunand, D.C.; Mortensen, A. . Dept. of Materials Science and Engineering)

    1994-06-15

    It is known that stiff, elastic ceramic reinforcements used in metal matrix composites can strongly influence dislocation creation, annihilation and motion within the matrix. In particular, mechanical interaction between reinforcement and matrix may result in dislocation densities in reinforced metals that exceed greatly those found in the unreinforced matrix metal, processed and strained analogously to the composite. Dislocation densities in metals are generally measured using transmission electron microscopy; however several precautions are required with this technique, which are exacerbated in the case of metal matrix composites because of thermal strain mismatch between matrix and reinforcement. Differential scanning calorimetry offers an alternative method of measuring dislocation densities in deformed metals, which has its limitations (dislocation densities must be relatively high, and the matrix must be highly pure and must recrystallize), but is well established for unreinforced metals, and is particularly suited for the measurement of high dislocation densities. In what follows the authors present an exploration of the use of this technique for deformed particle reinforced metals.

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

    SciTech Connect

    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.

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

    PubMed

    Wang, Bin; Jia, Yuan; Lin, Qiao

    2016-04-15

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

  10. Calorimetry study of microwave absorption of some solid materials.

    PubMed

    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. PMID:24779227

  11. Liposome/Graphene Oxide Interaction Studied by Isothermal Titration Calorimetry.

    PubMed

    Huang, Po-Jung Jimmy; Wang, Feng; Liu, Juewen

    2016-03-15

    The interaction between graphene oxide (GO) and lipid bilayers is important for fundamental surface science and many applications. In this work, isothermal titration calorimetry (ITC), cryo-TEM, and fluorescence spectroscopy were used to study the adsorption of three types of liposomes. Heat release was observed when GO was mixed with zwitterionic DOPC liposomes, while heat absorption occurred with cationic DOTAP liposomes. For comparison, anionic DOPG liposomes released heat when mixed with DOTAP. DOPC was adsorbed as intact liposomes, but DOTAP ruptured and induced stacking and folding of GO sheets. This study suggests the release of more water molecules from the GO surface when mixed with DOTAP liposomes. This can be rationalized by the full rupture of the DOTAP liposomes interacting with the whole GO surface, including hydrophobic regions, while DOPC liposomes only interact with a small area on GO near the edge, which is likely to be more hydrophilic. This interesting biointerfacial observation has enhanced our fundamental understanding of lipid/GO interactions. PMID:26908113

  12. Applying fast calorimetry on a spent nuclear fuel calorimeter

    SciTech Connect

    Liljenfeldt, Henrik

    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.

  13. Academic genealogy and direct calorimetry: a personal account.

    PubMed

    Jackson, Donald C

    2011-06-01

    Each of us as a scientist has an academic legacy that consists of our mentors and their mentors continuing back for many generations. Here, I describe two genealogies of my own: one through my PhD advisor, H. T. (Ted) Hammel, and the other through my postdoctoral mentor, Knut Schmidt-Nielsen. Each of these pathways includes distingished scientists who were all major figures in their day. The striking aspect, however, is that of the 14 individuals discussed, including myself, 10 individuals used the technique of direct calorimetry to study metabolic heat production in humans or other animals. Indeed, the patriarchs of my PhD genealogy, Antoine Lavoisier and Pierre Simon Laplace, were the inventors of this technique and the first to use it in animal studies. Brief summaries of the major accomplishments of each my scientific ancestors are given followed by a discussion of the variety of calorimeters and the scientific studies in which they were used. Finally, readers are encouraged to explore their own academic legacies as a way of honoring those who prepared the way for us. PMID:21652494

  14. Energetics of adsorbed CH3 on Pt(111) by calorimetry.

    PubMed

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

    2013-04-01

    The enthalpy and sticking probability for the dissociative adsorption of methyl iodide were measured on Pt(111) at 320 K and at low coverages (up to 0.04 ML, where 1 ML is equal to one adsorbate molecule for every surface Pt atom) using single crystal adsorption calorimetry (SCAC). At this temperature and in this coverage range, methyl iodide produces adsorbed methyl (CH(3,ad)) plus an iodine adatom (I(ad)). Combining the heat of this reaction with reported energetics for Iad gives the standard heat of formation of adsorbed methyl, ΔH(f)(0)(CH3,ad), to be −53 kJ/mol and a Pt(111)–CH3 bond energy of 197 kJ/mol. (The error bar of ±20 kJ/mol for both values is limited by the reported heat of formation of I(ad).) This is the first direct measurement of these values for any alkyl fragment on any surface. PMID:23461481

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

    NASA Astrophysics Data System (ADS)

    Akchurin, Nural

    2015-02-01

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

  16. High resolution optical calorimetry for synchrotron microbeam radiation therapy

    NASA Astrophysics Data System (ADS)

    Ackerly, T.; Crosbie, J. C.; Fouras, A.; Sheard, G. J.; Higgins, S.; Lewis, R. A.

    2011-03-01

    We propose the application of optical calorimetry to measure the peak to valley ratio for synchrotron microbeam radiation therapy (MRT). We use a modified Schlieren approach known as reference image topography (RIT) which enables one to obtain a map of the rate of change of the refractive index in a water bath from which the absorbed dose can be determined with sufficient spatial accuracy to determine the peak to valley ratio. We modelled the calorimetric properties of X-rays using a heated wire in a water bath. Our RIT system comprised a light source, a textured reference object and a camera and lens combination. We measured temperature contours and showed a plume rising from the heated wire. The total temperature change in water was 12 degrees C, 500 times greater than the calculated change from a 1 ms exposure on a synchrotron. At 1.0 ms, thermal diffusion will be the major cause of uncertainty in determining the peak to valley ratio, and we calculate thermal diffusion will reduce the measured peak to valley ratio to 76% of its initial value, but the individual microbeams will still resolve. We demonstrate proof of concept for measuring X-ray dose using a modified RIT method.

  17. On the interpretation of differential scanning calorimetry results for thermoelastic martensitic transformations: Athermal versus thermally activated kinetics

    SciTech Connect

    Van Humbeeck, J.; Planes, A.

    1996-05-01

    Experimentally, two distinct classes of martensitic transformations are considered: athermal and isothermal. In the former class, on cooling, at some well-defined start temperature (M{sub s}), isolated small regions of the martensitic product begin to appear in the parent phase. The transformation at any temperature appears to be instantaneous in practical time scales, and the amount of transformed material (x) does not depend on time, i.e., it increases at each step of lowering temperature. The transition is not completed until the temperature is lowered below M{sub f} (martensite finish temperature). The transformation temperatures are only determined by chemical (composition and degree of order) and microstructural factors. The external controlling parameter (T or applied stress) determines the free energy difference between the high and the low temperature phases, which provides the driving force for the transition. In the development of athermal martensite activation kinetics is secondary. Athermal martensite, as observed in the well known shape memory alloys Cu-Zn-Al, Cu-Al-Ni and Ni-Ti, cannot be attributed to a thermally activated mechanism for which kinetics are generally described by the Arrhenius rate equation. However, the latter has been applied by Lipe and Morris to results for the Martensitic Transformation of Cu-Al-Ni-B-Mn obtained by conventional Differential Scanning Calorimetry (DSC). It is the concern of the authors of this letter to point out the incongruences arising from the analysis of calorimetric results, corresponding to forward and reverse thermoelastic martensitic transformations, in terms of standard kinetic analysis based on the Arrhenius rate equation.

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

    NASA Astrophysics Data System (ADS)

    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.

  19. Correlation of the penetration enhancement with the influence of an alcohol/tocopheryl polyethylene glycol succinate (TPGS) cosolvent system on the molecular structure of the stratum corneum of nude mouse skin as examined by microscopic FTIR/DSC

    NASA Astrophysics Data System (ADS)

    Liou, Yi-Bo; Ho, Hsiu-O.; Chen, Shin-Yi; Sheu, Ming-Thau

    2009-10-01

    Tocopheryl polyethylene glycol succinate (TPGS) is a water-soluble derivative of natural source of vitamin E, which possesses a dual nature of lipophilicity and hydrophilicity, similar to a surface-active agent. The penetration enhancement of estradiol by an ethanol and TPGS cosolvent system (EtOH/TPGS) has been confirmed. In this study, the correlation of the penetration enhancement with the influence of the EtOH/TPGS cosolvent system on biophysical changes of the stratum corneum (SC) as examined by Fourier transformation infrared spectrometry differential scanning calorimetry (FTIR/DSC) was investigated. Thermotropic changes in the asymmetrical and symmetrical C-H stretching of hydrocarbon chains of lipids, and amide I and II bands that characterize the protein structure of the SC treated with different concentrations of the EtOH/TPGS cosolvent were examined in this investigation. Results demonstrated that a strong correlation of the influence on biophysical changes of the SC treated with the EtOH/TPGS cosolvent system with the penetration enhancement of estradiol by the corresponding cosolvent system was not evident. It was concluded that the incorporation of TPGS in the cosolvent system seemed only to have insignificantly modified the structural features of the SC. It was not obvious that the penetrant had encountered these modifications resulting in an improvement in the penetration of estradiol by TPGS.

  20. The Phase Structures of Nylon 6.6 as Studied by Temperature-modulated Calorimetry and Their Link to X-ray Structure and Molecular Motion.

    SciTech Connect

    Qui, Wulin; Habenschuss, Anton {Tony}; Wunderlich, Bernhard {nmn}

    2007-01-01

    The phase behavior of semicrystalline, dry nylon 6.6 is analyzed on the basis of differential scanning calorimetry, DSC, and quasi-isothermal, temperature-modulated DSC, TMDSC. The data were collected over the temperature range from below the glass transitions to above the isotropization. Based on the contributions of the vibrational motion to the heat capacity, as is available from the ATHAS Data Bank, and the multifaceted new calorimetry, as well as on information on X-ray diffraction, molecular dynamics simulation of paraffin crystals, and quasielastic neutron scattering, the following observations are made: (a) beginning at the glass transition temperature of the mobile-amorphous phase (Tg= 323 K), a broadened transition of the semicrystalline sample is observed which reaches to 342 K (Tg = 332.7 K). An additional rigid-amorphous phase, RAF, undergoes its separate, broad glass transition immediately thereafter (340-400 K, Tg {approx} 370 K). (b) The transition of the RAF, in turn, overlaps with increasing large-amplitude motion of the CH2 groups within the crystals and latent heat effects due to melting, recrystallization, and crystal annealing. (c) From 390 to 480 K the heat capacity of the crystals increasingly exceeds that of the melt due to additional entropy (disordering) contributions. Above 440 K, close to the Brill temperature, the heat capacity seems to drop to the level of the melt. (d) If observation (c) is confirmed, some locally reversible melting is present on the crystal surfaces. (e) The increasing large-amplitude motion is described as a glass transition of the crystals, occurring below the melting point, at 409 K. The assumption of a separate glass transition in the ordered phase was previously successful in analyzing aliphatic poly(oxide)s and mesophases. The full description of the globally metastable, semicrystalline phase structure of nylons, thus, needs information on the glass transitions of the two amorphous phases and the ordered phase

  1. Annual meeting of the Calorimetry Exchange Program: minutes--April 24-25, 1991

    SciTech Connect

    1991-12-31

    On April 24-25, 1991, people from seven DOE organizations participated in the annual meeting of the Calorimetry Exchange Program. The meeting featured a review of the statistical analysis of the calorimetry and gamma-ray data submitted to the exchange program during 1990. The meeting also enabled the group to review progress of five projects concerning a tritium exchange program, reprogramming of the database, a catalogue of measurement techniques, additional samples, and recharacterization of the current sample. There were presentations on recent advances in calorimetry and gamma-ray measurements.

  2. Bridging Experiments and Native-Centric Simulations of a Downhill Folding Protein.

    PubMed

    Naganathan, Athi N; De Sancho, David

    2015-11-25

    Experiments and atomistic simulations have independently contributed to the mechanistic understanding of protein folding. However, a coherent detailed picture explicitly combining both is currently lacking, a problem that seriously limits the amount of information that can be extracted. An alternative to atomistic models with physics-based potentials is the native-centric (i.e., Go̅ type) coarse-grained models, which for many years have been successfully employed to qualitatively understand features of protein folding energy landscapes. Again, quantitative validation of Go̅ models against experimental equilibrium unfolding curves is often not attempted. Here we use an atomistic topology-based model to study the folding mechanism of PDD, a protein that folds over a marginal thermodynamic barrier of ∼0.5 kBT at midpoint conditions. We find that the simulations are in exquisite agreement with several equilibrium experimental measurements including differential scanning calorimetry (DSC), an observable that is possibly the most challenging to reproduce from explicit-chain models. The dynamics, inferred using a detailed Markov state model, display a classical Chevron-like trend with a continuum of relaxation times under both folding and unfolding conditions, a signature feature of downhill folding. The number of populated microstates and the connectivity between them are shown to be temperature dependent with a maximum near the thermal denaturation midpoint, thus linking the macroscopic observation of a peak in the DSC profile of downhill folding proteins and the underlying microstate dynamics. The mechanistic picture derived from our analysis thus sheds light on the intricate and tunable nature of the downhill protein folding ensembles. In parallel, our work highlights the power of coarse-grained models to reproduce experiments at a quantitative level while also pointing at specific directions for their improvement. PMID:26524123

  3. An Integrated-Circuit Temperature Sensor for Calorimetry and Differential Temperature Measurement.

    ERIC Educational Resources Information Center

    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)

  4. Calorimetry exchange program amendment to 3rd quarter CY92 report LLNL isotopic data

    SciTech Connect

    Barnett, T.M.

    1996-08-01

    This report is a series of ammendments to the Calorimetry Exchange Quarterly Data Report for third quarter CY1992. The ammendment is needed due to reporting errors encountered in the Lawrence Livermore National Laboratory isotopic data.

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

    ERIC Educational Resources Information Center

    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)

  6. Calorimetry in Medical Applications: Single-Photon Emission Computed Tomography and Positron Emission Tomography

    SciTech Connect

    Chen, C.-T.

    2006-10-27

    Positron emission tomography (PET) and single-photon emission computed tomography (SPECT), two nuclear medicine imaging modalities broadly used in clinics and research, share many common instrumentation, detector, and electronics technology platforms with calorimetry in high-energy physics, astronomy, and other physics sciences. Historically, advances made in calorimetry had played major roles in the development of novel approaches and critical technologies essential to the evolution of PET and SPECT. There have also been examples in which PET/SPECT developments had led to new techniques in calorimetry for other application areas. In recent years, several innovations have propelled advances in both calorimetry in general and PET/SPECT in particular. Examples include time-of-flight (TOF) measurements, silicon photomultipliers (SiPMs), etc.

  7. Relaxation process of Fe(CuNb)SiB amorphous alloys investigated by dynamical calorimetry

    SciTech Connect

    Zhu, J.; Clavaguera-Mora, M.T.; Clavaguera, N.

    1997-03-01

    Differential scanning calorimetry and dynamic differential scanning calorimetry were used to analyze the relaxation process of Fe(CuNb)SiB amorphous alloys. The Curie temperature (T{sub C}) evolution of the amorphous phase during relaxation as a function of heating rate, time and pre-annealing temperature were measured. Two distinct relaxation processes are observed, consequent with topological and chemical short range order changes. {copyright} {ital 1997 American Institute of Physics.}

  8. Development of GEM-Based Digital Hadron Calorimetry Using the SLAC KPiX Chip

    SciTech Connect

    White, A.; /Texas U., Arlington /Washington U., Seattle /Unlisted /SLAC

    2012-04-12

    The development of Digital Hadron Calorimetry for the SiD detector Concept for the International Linear Collider is described. The jet energy requirements of the ILC physics program are discussed. The concept of GEM-based digital hadron calorimetry is presented, followed by a description of, and results from, prototype detectors. Plans are described for the construction of 1m{sup 2} GEM-DHCAL planes to be tested as part of a future calorimeter stack.

  9. Simultaneous Calorimetric, Dielectric, and SAXS/WAXS Experiments During Polymer Crystallization

    NASA Astrophysics Data System (ADS)

    Wurm, A.; Minakov, A. A.; Schick, C.

    As extensively described in Chaps. 5 and 7, high-intensity synchrotron radiation offers the possibility to perform simultaneously and in real time small, medium, and wide angle X-ray scattering (SAXS, MAXS, and WAXS, nobreak respectively). In order to understand a broad range of physical phenomena like, for example nucleation, crystallization, and other phase transitions in polymers, polymer-based nobreak composites, or in liquid crystals simultaneous experiments with a nobreak combination of different methods are useful. Due to different sample geometry and thermal nobreak conditions, it is usually difficult to compare the results of different individual experiments. As an important supplement to the classical techniques for studying crystallization like SAXS, WAXS, or differential scanning calorimetry, measurements which test molecular mobility like dielectric or mechanical spectroscopy are of interest during isothermal and non-isothermal crystallization. From such simultaneous experiments, we can learn about the existence of pre-ordered structures before formation of crystals, as detected by DSC or X-ray scattering. In this chapter, we present the development of a device for simultaneous measurements of electrical properties and SAXS/WAXS intensities, which was extended to a microcalorimeter and allows measuring thermal properties like heat capacity and thermal conductivity additionally at the same time and at the same sample volume.

  10. CALOCUBE: an approach to high-granularity and homogenous calorimetry for space based detectors

    NASA Astrophysics Data System (ADS)

    Bongi, M.; Adriani, O.; Albergo, S.; Auditore, L.; Bagliesi, M. G.; Berti, E.; Bigongiari, G.; Boezio, M.; Bonechi, L.; Bonechi, S.; Bonvicini, V.; Bottai, S.; Brogi, P.; Carotenuto, G.; Cassese, A.; Castellini, G.; Cattaneo, P. W.; Cauz, D.; Cumani, P.; D'Alessandro, R.; Detti, S.; Fasoli, M.; Gregorio, A.; Lamberto, A.; Lenzi, P.; Maestro, P.; Marrocchesi, P. S.; Mezzasalma, A.; Miritello, M.; Mori, N.; Papini, P.; Pauletta, G.; Rappazzo, G. F.; Rappoldi, A.; Ricciarini, S.; Spillantini, P.; Starodubtsev, O.; Sulaj, A.; Tiberio, A.; Trifirò, A.; Trimarchi, M.; Vannuccini, E.; Vedda, A.; Zampa, G.; Zampa, N.; Zerbo, B.

    2015-02-01

    Future space experiments dedicated to the observation of high-energy gamma and cosmic rays will increasingly rely on a highly performing calorimetry apparatus, and their physics performance will be primarily determined by the geometrical dimensions and the energy resolution of the calorimeter deployed. Thus it is extremely important to optimize its geometrical acceptance, the granularity, and its absorption depth for the measurement of the particle energy with respect to the total mass of the apparatus which is the most important constraint for a space launch. The proposed design tries to satisfy these criteria while staying within a total mass budget of about 1.6 tons. Calocube is a homogeneous calorimeter instrumented with Cesium iodide (CsI) crystals, whose geometry is cubic and isotropic, so as to detect particles arriving from every direction in space, thus maximizing the acceptance; granularity is obtained by filling the cubic volume with small cubic CsI crystals. The total radiation length in any direction is more than adequate for optimal electromagnetic particle identification and energy measurement, whilst the interaction length is at least suficient to allow a precise reconstruction of hadronic showers. Optimal values for the size of the crystals and spacing among them have been studied. The design forms the basis of a three-year R&D activity which has been approved and financed by INFN. An overall description of the system, as well as results from preliminary tests on particle beams will be described.