Stearic acid (67.83℃) and myristic acid (52.32℃) have high melting temperatures that can limit their use as phase change material (PCM) in low temperature solar heating applications such as solar space and greenhous...Stearic acid (67.83℃) and myristic acid (52.32℃) have high melting temperatures that can limit their use as phase change material (PCM) in low temperature solar heating applications such as solar space and greenhouse heating in regard to climatic requirements. However, their melting temperatures can be adjusted to a suitable value by preparing a eutectic mixture of the myristic acid (MA) and the stearic acid (SA). In the present study, the thermal analysis based on differential scanning calorimetry (DSC) technique shows that the mixture of myristic acid (MA) and stearic acid (SA) in the respective composition (by mass) of 64% and 36% forms a eutectic mixture having melting temperature of 44.13℃ and the latent heat of fusion of 182.4J·g-1. The thermal energy storage characteristics of the MA-SA eutectic mixture filled in the annulus of two concentric pipes were also experimentally established. The heat recovery rate and heat charging/discharging fractions were determined with respect to the change in the mass flow rate and the inlet temperature of heat transfer fluid. Based on the results obtained by DSC analysis and by the heat charg- ing/discharging processes of the PCM, it can be concluded that the MA-SA eutectic mixture is a potential material for low temperature thermal energy storage applications in terms of its thermo-physical and thermal characteristics.展开更多
The miscibility and crystallization of solution casting biodegradable poly(3-hydroxybuty- rate)/poly(ethylene succinate) (PHB/PES) blends was investigated by differential scanning calorimetry, rheology, and opti...The miscibility and crystallization of solution casting biodegradable poly(3-hydroxybuty- rate)/poly(ethylene succinate) (PHB/PES) blends was investigated by differential scanning calorimetry, rheology, and optical microscopy. The blends showed two glass transition temperatures and a depression of melting temperature of PHB with compositions in phase diagram, which indicated that the blend was partially miscible. The morphology observation supported this result. It was found that the PHB and PES can crystallize simultaneously or upon stepwise depending on the crystallization temperatures and compositions. The spherulite growth rate of PHB increased with increasing of PES content. The influence of compositions on the spherulitic growth rate for the partially miscible polymer blends was discussed.展开更多
The goal of the present work was to study the effects of acid treatment on the foaming properties of a soybean protein isolate (SPI) and its fractions, glycinin (11S) and β-conglycinin (7S). The structural char...The goal of the present work was to study the effects of acid treatment on the foaming properties of a soybean protein isolate (SPI) and its fractions, glycinin (11S) and β-conglycinin (7S). The structural characteristics, interfacial properties, foaming capacity and stability of the treated proteins were studied. Results from surface hydrophobicity and differential scanning calorimetry (DSC) showed that the acid treatment caused the complete denaturation of 11S and a partial denaturation of 7S. This protein unfolding affected their interracial properties, which led to an improvement in the foaming properties of both protein fractions and isolate. Treated 7S showed the best behavior in the rearrangement process, probably due to its smaller size and its modified structural characteristics. All treated proteins showed stronger interracial films. The foams of treated proteins were destabilized mostly due to gravitational drainage rather than Ostwald ripening.展开更多
A real-time sensing of the molecular distillation process temperature by a FLUKE brand thermograph Ti50 IR FlexCam and thermography technique was realized. After completion of the molecular distillation, three propert...A real-time sensing of the molecular distillation process temperature by a FLUKE brand thermograph Ti50 IR FlexCam and thermography technique was realized. After completion of the molecular distillation, three properties of heat transport chain cuts and residues obtained in the process were estimated by Differential Scanning Calorimetry (DSC) (specific heat, enthalpy, thermal conductivity). These properties are of great importance for improving oil characterization and for future modeling and simulation of the molecular distillation process. The results show that through the method of Differential Scanning Calorimetry, profiles have been obtained from the variation of specific heat, enthalpy and thermal condutivity as a function of temperature for samples of cuts from the distillation (ASTM D-2892) and fractions of distillate and residue from the process of molecular distillation.展开更多
A series of caprolactam ionic liquids(ILs) containing incorporated halide anions were synthesized.Their physical properties,such as melting points,heats of fusion and heat capacities,were measured by differential scan...A series of caprolactam ionic liquids(ILs) containing incorporated halide anions were synthesized.Their physical properties,such as melting points,heats of fusion and heat capacities,were measured by differential scanning calorimeter(DSC).The results indicate that these ionic liquids exhibit proper melting points,high value of heats of fusion,and satisfying heat capacities which are suitable for thermal energy storage applications.展开更多
Soft magnetic composites (SMCs) were prepared from three different ferromagnetic powder particles: iron powder ASC 100.29, spherical FeSi particles and vitroperm (Fe73CulNb3Si16B7) flakes. Two types of hybrid org...Soft magnetic composites (SMCs) were prepared from three different ferromagnetic powder particles: iron powder ASC 100.29, spherical FeSi particles and vitroperm (Fe73CulNb3Si16B7) flakes. Two types of hybrid organic-inorganic phenolic resins modified with either silica nanoparticles or boron were used to design a thin insulating layer perfect- ly covering the ferromagnetic particles. Fourier transform infrared (FTIR) spectrometry confirmed an incorporation of silica or boron into the polymer matrix, which manifested itself through an improved thermal stability of the hybrid resins verified by thermogravimetric-differential scanning calorimetry (TG-DSC) analysis. The core-shell particles prepared from the ferromagnetic powder particles and the modified hybrid resins were further compacted to the cylindrical and toroidal shapes for the mechanical, electrical and magnetic testing. A uniform distribution of the resin between the ferromagnetic particles was evidenced by scanning electron microscope (SEM) analysis, which was also reflected in a rather high value of the electrical resistivity. A low porosity and extraordinary high values of mechanical hardness and flexural strength were found in SMC consisting of the iron powder and phenolic resin modified with boron. The coercive fields of the prepared samples were comparable with the commercial SMCs.展开更多
The effects of the retrogression heating rate(340℃/min,57℃/min,4.3℃/min)on the microstructures and mechanical properties of aluminum alloy 7050 were investigated by means of hardness measurement,tensile properties ...The effects of the retrogression heating rate(340℃/min,57℃/min,4.3℃/min)on the microstructures and mechanical properties of aluminum alloy 7050 were investigated by means of hardness measurement,tensile properties testing,differential scanning calorimetry(DSC)and transmission electron microscopy(TEM).The results show that the retrogression heating rate significantly affects the microstructures and mechanical properties of the alloys treated by retrogression and re-aging(RRA)process, and it is found that the medium rate(57℃/min)leads to the highest mechanical properties.The strengthening phases in the matrix are mainly the fine dispersed η′precipitates and GP zones,and the grain boundary precipitates are coarse and discontinuous η phases.展开更多
Basing upon the tonality analytic method, the present paper aims at: (1) Drawing attention to the subordination of the minor key vs. the major key in the chord classification, using the same methodology; and (2) ...Basing upon the tonality analytic method, the present paper aims at: (1) Drawing attention to the subordination of the minor key vs. the major key in the chord classification, using the same methodology; and (2) Showing the differences for the major key and the minor (harmonic) key in the classification of chords, as an aspect of importance for interpreting a piece's tonal structure diagram. The relations between chords appearing in the major and minor (harmonic) key will be shown by applying the comparisons of: (1) third-based chords; and (2) degrees in the C major and A minor keys, on which the same diatonic chords appear.展开更多
Triacylglycerols are the main constituents of natural fats and oils and contribute directly to their texture and flavor. The DSC (differential scanning calorimetry) of fats and oils is usually performed in order to ...Triacylglycerols are the main constituents of natural fats and oils and contribute directly to their texture and flavor. The DSC (differential scanning calorimetry) of fats and oils is usually performed in order to characterize their melting and crystallization characteristics. The effect of the chemically catalyzed interesterification of two vegetable oils, i.e. palm stearin and linseed oil, on the thermal behavior of the product is studied. The objective of this study is to analyze the impact of the transesterification reaction conditions and of the initial amounts of oils on the thermal behavior of the product. This work shows that both cooling and heating DSC thermograms undergo significant changes as the result of the mixture of linseed oil and palm stearin and of their transesterification.展开更多
The purpose of this work was to study the thermal characterization of oils extracted from native seeds and fruits of the Argentina, Uruguayan region. This is important because it's necessary to find new applications ...The purpose of this work was to study the thermal characterization of oils extracted from native seeds and fruits of the Argentina, Uruguayan region. This is important because it's necessary to find new applications for food industry. Uruguayan wild cardoon seed, Argentinian wild papaya seeds, Argentinian avocado pulp, Argentinian cherimoya seeds, Argentinian grapeseeds and four commercial brands of chia oils were studied. The thermal behaviors of the oils were analyzed on a differential scanning calorimetry (DSC), TA Instrument, Q20 model equipped with an intercooler. These oils' thermal profiles presented differences, which are related to the compositions of fatty acids and triacylglycerols. The thermogram for the chia oil, with a high content of linolenic acid, presented a very important peak at about -40 ℃; whereas, the papaya oil with an oleic acid content of 74%, showed a peak at about -3 ℃. When comparing the thermal behaviors of these oils to commercial brand oils, it was found that the chia oil is similar to the flaxseed oil, the papaya similar to the olive oil and the avocado similar to the rice bran oil. The avocado oil, in particular, presents high solid content at cold store or winter temperatures, which would make its use in those conditions difficult (for example, a cosmetic cream or gourmet oil). In conclusion, the thermal behavior of one oil sample as determined by DSC provides valuable information with regards to the possible use of new oils of American origin as replacement of usual commercial others.展开更多
Physicochemical and sensory characteristics of restructured meat of common carp (Cyprinus carpio) fortified with 0-8 g/100 g of chia seed flour (CSF) was evaluated. It had a higher nutritional value (higher fibre...Physicochemical and sensory characteristics of restructured meat of common carp (Cyprinus carpio) fortified with 0-8 g/100 g of chia seed flour (CSF) was evaluated. It had a higher nutritional value (higher fibre content and protein retention] (p 〈 0.05) and better cooking characteristics (higher cooking yield and moisture retention) (p 〈 0.05) than the control. The colour (a*, b*) increased; lightness and whiteness index decrease (p 〈 0.05). Hardness increase (p 〈 0.05) occurred because of CSF addition. Differential scanning calorimetry showed that fibre fortification did not interfere with the thermal transitions of the restructured meat. No significant differences were detected with the preference test scores of 4% or 8% CSF compared with the control. Restructured (4%-8% CSF) had a higher content of fibre and fat, which could be linoleic and linolenic acid, and an increase in the content of protein compared with those of commercial products, among had 1.62 and 2.25 mg AGE/g. Therefore, the restructured properties of common carp were governed by CSF addition.展开更多
The thermal decomposition process was studied by the TG–DTA analyzer. The results show that the decomposition process of sodium hydroxyethyl sulfonate consisted of three stages: the mass loss for the first, the secon...The thermal decomposition process was studied by the TG–DTA analyzer. The results show that the decomposition process of sodium hydroxyethyl sulfonate consisted of three stages: the mass loss for the first, the second and third stages may be about the groups of CH_3CH_2OH, CH_3CHO and SO_2 volatilized, respectively. The decomposition residuum of three stages was analyzed by FT-IR, and the results of FT-IR agreed with the decomposition process predicted by theoretical weight loss. The specific heat capacity of sodium hydroxyethyl sulfonate was determined by differential scanning calorimetry(DSC). The melting temperature and melting enthalpy were obtained to be 465.41 K and 25.69 kJ·mol^(-1), respectively. The molar specific heat capacity of sodium hydroxyethyl sulfonate was determinated from 310.15 K to 365.15 K and expressed as a function of temperature.展开更多
A new kind of modified thermoset resins were synthesized by phase-transfer Williamson reaction from novolac resin and mixtures of allyl- and propargyl-chlorides. The compositions of the resins were defined by 1H NMR ...A new kind of modified thermoset resins were synthesized by phase-transfer Williamson reaction from novolac resin and mixtures of allyl- and propargyl-chlorides. The compositions of the resins were defined by 1H NMR (nuclear magnetic resonanse) spectroscopy and the dependence of the cured materials properties on the composition was established. Increase of a propargyl content resulted in char yield raise and the maximum value had been found for propargylated resin--58%. DSC (differential scanning calorimetry)-analysis of the resins has demonstrated that exothermic enthalpy of the curing process could be adjusted by varying the content of propargyl and allyl groups in the resin.展开更多
Poly(ethylene terephthalate)(PET)was synthesized by the in-situ polymerization method using layered double hydrotalcite(LDH)as the catalyst,and the thermal and flame retardation properties of PET were investigated as ...Poly(ethylene terephthalate)(PET)was synthesized by the in-situ polymerization method using layered double hydrotalcite(LDH)as the catalyst,and the thermal and flame retardation properties of PET were investigated as required.As identified by differential scanning calorimetry(DSC)and thermogravimetric(TGA)analysis,the crystallization rate and thermal degradation temperature of the as-prepared PET sample were enhanced compared with commercial PET sample.It was confirmed from the fire-resistant property study that the LDH can be used as an efficient flame-retardant besides functioning as a catalyst in the transesterification/polycondensation process for PET synthesis.展开更多
基金Supported by the Research Fund of Gaziosmanpasa University (No.2003/42).
文摘Stearic acid (67.83℃) and myristic acid (52.32℃) have high melting temperatures that can limit their use as phase change material (PCM) in low temperature solar heating applications such as solar space and greenhouse heating in regard to climatic requirements. However, their melting temperatures can be adjusted to a suitable value by preparing a eutectic mixture of the myristic acid (MA) and the stearic acid (SA). In the present study, the thermal analysis based on differential scanning calorimetry (DSC) technique shows that the mixture of myristic acid (MA) and stearic acid (SA) in the respective composition (by mass) of 64% and 36% forms a eutectic mixture having melting temperature of 44.13℃ and the latent heat of fusion of 182.4J·g-1. The thermal energy storage characteristics of the MA-SA eutectic mixture filled in the annulus of two concentric pipes were also experimentally established. The heat recovery rate and heat charging/discharging fractions were determined with respect to the change in the mass flow rate and the inlet temperature of heat transfer fluid. Based on the results obtained by DSC analysis and by the heat charg- ing/discharging processes of the PCM, it can be concluded that the MA-SA eutectic mixture is a potential material for low temperature thermal energy storage applications in terms of its thermo-physical and thermal characteristics.
基金ACKNOWLEDGMENT This work was supported by the Key Science Foundation of Education Ministry of China and the Anhui Science Foundation.
文摘The miscibility and crystallization of solution casting biodegradable poly(3-hydroxybuty- rate)/poly(ethylene succinate) (PHB/PES) blends was investigated by differential scanning calorimetry, rheology, and optical microscopy. The blends showed two glass transition temperatures and a depression of melting temperature of PHB with compositions in phase diagram, which indicated that the blend was partially miscible. The morphology observation supported this result. It was found that the PHB and PES can crystallize simultaneously or upon stepwise depending on the crystallization temperatures and compositions. The spherulite growth rate of PHB increased with increasing of PES content. The influence of compositions on the spherulitic growth rate for the partially miscible polymer blends was discussed.
文摘The goal of the present work was to study the effects of acid treatment on the foaming properties of a soybean protein isolate (SPI) and its fractions, glycinin (11S) and β-conglycinin (7S). The structural characteristics, interfacial properties, foaming capacity and stability of the treated proteins were studied. Results from surface hydrophobicity and differential scanning calorimetry (DSC) showed that the acid treatment caused the complete denaturation of 11S and a partial denaturation of 7S. This protein unfolding affected their interracial properties, which led to an improvement in the foaming properties of both protein fractions and isolate. Treated 7S showed the best behavior in the rearrangement process, probably due to its smaller size and its modified structural characteristics. All treated proteins showed stronger interracial films. The foams of treated proteins were destabilized mostly due to gravitational drainage rather than Ostwald ripening.
文摘A real-time sensing of the molecular distillation process temperature by a FLUKE brand thermograph Ti50 IR FlexCam and thermography technique was realized. After completion of the molecular distillation, three properties of heat transport chain cuts and residues obtained in the process were estimated by Differential Scanning Calorimetry (DSC) (specific heat, enthalpy, thermal conductivity). These properties are of great importance for improving oil characterization and for future modeling and simulation of the molecular distillation process. The results show that through the method of Differential Scanning Calorimetry, profiles have been obtained from the variation of specific heat, enthalpy and thermal condutivity as a function of temperature for samples of cuts from the distillation (ASTM D-2892) and fractions of distillate and residue from the process of molecular distillation.
基金Supported by the National Natural Science Foundation of China (21176010, 20706005).
文摘A series of caprolactam ionic liquids(ILs) containing incorporated halide anions were synthesized.Their physical properties,such as melting points,heats of fusion and heat capacities,were measured by differential scanning calorimeter(DSC).The results indicate that these ionic liquids exhibit proper melting points,high value of heats of fusion,and satisfying heat capacities which are suitable for thermal energy storage applications.
基金Supported by the Slovak Research and Development Agency under the contracts(APVV-0222-10)the Operational Program"Research and Development"financed through European Regional Development Fund(ITMS 26220220105)the Scientific Grant Agency of the Ministry of Education of Slovak Republic and the Slovak Academy of Sciences,projects(VEGA 1/0861/12,VEGA 1/0862/12,VEGA VEGA 2/0155/12)
文摘Soft magnetic composites (SMCs) were prepared from three different ferromagnetic powder particles: iron powder ASC 100.29, spherical FeSi particles and vitroperm (Fe73CulNb3Si16B7) flakes. Two types of hybrid organic-inorganic phenolic resins modified with either silica nanoparticles or boron were used to design a thin insulating layer perfect- ly covering the ferromagnetic particles. Fourier transform infrared (FTIR) spectrometry confirmed an incorporation of silica or boron into the polymer matrix, which manifested itself through an improved thermal stability of the hybrid resins verified by thermogravimetric-differential scanning calorimetry (TG-DSC) analysis. The core-shell particles prepared from the ferromagnetic powder particles and the modified hybrid resins were further compacted to the cylindrical and toroidal shapes for the mechanical, electrical and magnetic testing. A uniform distribution of the resin between the ferromagnetic particles was evidenced by scanning electron microscope (SEM) analysis, which was also reflected in a rather high value of the electrical resistivity. A low porosity and extraordinary high values of mechanical hardness and flexural strength were found in SMC consisting of the iron powder and phenolic resin modified with boron. The coercive fields of the prepared samples were comparable with the commercial SMCs.
基金Project(2005CB623700) supported by the National Basic Research Program of China
文摘The effects of the retrogression heating rate(340℃/min,57℃/min,4.3℃/min)on the microstructures and mechanical properties of aluminum alloy 7050 were investigated by means of hardness measurement,tensile properties testing,differential scanning calorimetry(DSC)and transmission electron microscopy(TEM).The results show that the retrogression heating rate significantly affects the microstructures and mechanical properties of the alloys treated by retrogression and re-aging(RRA)process, and it is found that the medium rate(57℃/min)leads to the highest mechanical properties.The strengthening phases in the matrix are mainly the fine dispersed η′precipitates and GP zones,and the grain boundary precipitates are coarse and discontinuous η phases.
文摘Basing upon the tonality analytic method, the present paper aims at: (1) Drawing attention to the subordination of the minor key vs. the major key in the chord classification, using the same methodology; and (2) Showing the differences for the major key and the minor (harmonic) key in the classification of chords, as an aspect of importance for interpreting a piece's tonal structure diagram. The relations between chords appearing in the major and minor (harmonic) key will be shown by applying the comparisons of: (1) third-based chords; and (2) degrees in the C major and A minor keys, on which the same diatonic chords appear.
文摘Triacylglycerols are the main constituents of natural fats and oils and contribute directly to their texture and flavor. The DSC (differential scanning calorimetry) of fats and oils is usually performed in order to characterize their melting and crystallization characteristics. The effect of the chemically catalyzed interesterification of two vegetable oils, i.e. palm stearin and linseed oil, on the thermal behavior of the product is studied. The objective of this study is to analyze the impact of the transesterification reaction conditions and of the initial amounts of oils on the thermal behavior of the product. This work shows that both cooling and heating DSC thermograms undergo significant changes as the result of the mixture of linseed oil and palm stearin and of their transesterification.
文摘The purpose of this work was to study the thermal characterization of oils extracted from native seeds and fruits of the Argentina, Uruguayan region. This is important because it's necessary to find new applications for food industry. Uruguayan wild cardoon seed, Argentinian wild papaya seeds, Argentinian avocado pulp, Argentinian cherimoya seeds, Argentinian grapeseeds and four commercial brands of chia oils were studied. The thermal behaviors of the oils were analyzed on a differential scanning calorimetry (DSC), TA Instrument, Q20 model equipped with an intercooler. These oils' thermal profiles presented differences, which are related to the compositions of fatty acids and triacylglycerols. The thermogram for the chia oil, with a high content of linolenic acid, presented a very important peak at about -40 ℃; whereas, the papaya oil with an oleic acid content of 74%, showed a peak at about -3 ℃. When comparing the thermal behaviors of these oils to commercial brand oils, it was found that the chia oil is similar to the flaxseed oil, the papaya similar to the olive oil and the avocado similar to the rice bran oil. The avocado oil, in particular, presents high solid content at cold store or winter temperatures, which would make its use in those conditions difficult (for example, a cosmetic cream or gourmet oil). In conclusion, the thermal behavior of one oil sample as determined by DSC provides valuable information with regards to the possible use of new oils of American origin as replacement of usual commercial others.
文摘Physicochemical and sensory characteristics of restructured meat of common carp (Cyprinus carpio) fortified with 0-8 g/100 g of chia seed flour (CSF) was evaluated. It had a higher nutritional value (higher fibre content and protein retention] (p 〈 0.05) and better cooking characteristics (higher cooking yield and moisture retention) (p 〈 0.05) than the control. The colour (a*, b*) increased; lightness and whiteness index decrease (p 〈 0.05). Hardness increase (p 〈 0.05) occurred because of CSF addition. Differential scanning calorimetry showed that fibre fortification did not interfere with the thermal transitions of the restructured meat. No significant differences were detected with the preference test scores of 4% or 8% CSF compared with the control. Restructured (4%-8% CSF) had a higher content of fibre and fat, which could be linoleic and linolenic acid, and an increase in the content of protein compared with those of commercial products, among had 1.62 and 2.25 mg AGE/g. Therefore, the restructured properties of common carp were governed by CSF addition.
文摘The thermal decomposition process was studied by the TG–DTA analyzer. The results show that the decomposition process of sodium hydroxyethyl sulfonate consisted of three stages: the mass loss for the first, the second and third stages may be about the groups of CH_3CH_2OH, CH_3CHO and SO_2 volatilized, respectively. The decomposition residuum of three stages was analyzed by FT-IR, and the results of FT-IR agreed with the decomposition process predicted by theoretical weight loss. The specific heat capacity of sodium hydroxyethyl sulfonate was determined by differential scanning calorimetry(DSC). The melting temperature and melting enthalpy were obtained to be 465.41 K and 25.69 kJ·mol^(-1), respectively. The molar specific heat capacity of sodium hydroxyethyl sulfonate was determinated from 310.15 K to 365.15 K and expressed as a function of temperature.
文摘A new kind of modified thermoset resins were synthesized by phase-transfer Williamson reaction from novolac resin and mixtures of allyl- and propargyl-chlorides. The compositions of the resins were defined by 1H NMR (nuclear magnetic resonanse) spectroscopy and the dependence of the cured materials properties on the composition was established. Increase of a propargyl content resulted in char yield raise and the maximum value had been found for propargylated resin--58%. DSC (differential scanning calorimetry)-analysis of the resins has demonstrated that exothermic enthalpy of the curing process could be adjusted by varying the content of propargyl and allyl groups in the resin.
文摘Poly(ethylene terephthalate)(PET)was synthesized by the in-situ polymerization method using layered double hydrotalcite(LDH)as the catalyst,and the thermal and flame retardation properties of PET were investigated as required.As identified by differential scanning calorimetry(DSC)and thermogravimetric(TGA)analysis,the crystallization rate and thermal degradation temperature of the as-prepared PET sample were enhanced compared with commercial PET sample.It was confirmed from the fire-resistant property study that the LDH can be used as an efficient flame-retardant besides functioning as a catalyst in the transesterification/polycondensation process for PET synthesis.