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Tytuł:
The Effect of Detonator Shell Materials on Detonation Calorimetry Results
Autorzy:
Němec, Ondřej
Musil, Tomáš
Künzel, Martin
Powiązania:
https://bibliotekanauki.pl/articles/1062738.pdf
Data publikacji:
2020
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
detonation calorimetry
detonator
PETN
heat of detonation
bomb calorimetry
Opis:
Detonation calorimetry is a method for the determination of the heat released by the detonation of an explosive charge. Compared to classical combustion calorimetry, detonation calorimetry requires an inert atmosphere, a large sample mass and a detonator for its initiation. This detonator releases some energy for which the results must be corrected. Four types of detonator have been tested in the calorimeter alone and also in combination with explosive charges of PETN. It was found that the aluminium shell of the detonator considerably increases the apparent heat of detonation of the PETN samples in a vacuum, while the presence of combustible (polymeric) components has the opposite effect. Pressurization of the calorimetric vessel with nitrogen gas only partially suppresses these effects. The preferred technique is to use copper or glass confinement in a high pressure inert atmosphere.
Źródło:
Central European Journal of Energetic Materials; 2020, 17, 4; 552-565
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inhibition study of adenosine deaminase by caffeine using spectroscopy and isothermal titration calorimetry.
Autorzy:
Saboury, A
Divsalar, A
Ataie, G
Amanlou, M
Moosavi-Movahedi, A
Hakimelahi, G
Powiązania:
https://bibliotekanauki.pl/articles/1043464.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
calorimetry
inhibition
caffeine
adenosine deaminase
Opis:
Kinetic and thermodynamic studies were made on the effect of caffeine on the activity of adenosine deaminase in 50 mM sodium phosphate buffer, pH 7.5, using UV spectrophotometry and isothermal titration calorimetry (ITC). An uncompetitive inhibition was observed for caffeine. A graphical fitting method was used for determination of binding constant and enthalpy of inhibitor binding by using isothermal titration microcalorimetry data. The dissociation-binding constant is equal to 350 μM by the microcalorimetry method, which agrees well with the value of 342 μM for the inhibition constant that was obtained from the spectroscopy method. Positive dependence of caffeine binding on temperature indicates a hydrophobic interaction.
Źródło:
Acta Biochimica Polonica; 2003, 50, 3; 849-855
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Porównanie wyników ciepła hydratacji metodą semiadiabatyczną i metodą izotermiczną oraz wyznaczenie współczynnika korelacji
Establishing of the correlation coefficient between results of heat of hydration semi-adiabatic and isothermal method
Autorzy:
Baran, T.
Francuz, P.
Duszak, B.
Pichniarczyk, P.
Hernik, K.
Powiązania:
https://bibliotekanauki.pl/articles/391886.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Ceramiki i Materiałów Budowlanych
Tematy:
cement
ciepło hydratacji
kalorymetria
kalorymetria semiadiabatyczna
kalorymetria izotermiczna
porównanie
współczynnik korelacji
hydration heat
calorimetry
semi-adiabatic calorimetry
isothermal calorimetry
comparison
correlation coefficient
Opis:
Podstawowym celem pracy była próba określenia współczynnika korelacji pomiędzy wynikami badań ciepła hydratacji cementów wykonanych metodą izotermiczną i metodą semiadiabatyczną według PN-EN 196-9. Należy zaznaczyć, że taka korelacja istnieje dla wyniku badania ciepła hydratacji po 41 godzinach metodą semiadiabatyczną według PN-EN 196-9 i wyniku badania po 168 godzinach metodą rozpuszczania według PN-EN 196-8. Badania porównawcze ciepła hydratacji metodą izotermiczną i semiadiabatyczną według PN-EN 196-9 oraz próba określenia współczynnika korelacji pomiędzy tymi metodami prowadzono na wybranych cementach przemysłowych, zróżnicowanych z uwagi na rodzaj i ilość dodatku do cementu oraz stopień rozdrobnienia cementu. Współczynniki korelacji pomiędzy metodą semiadiabatyczną i izotermiczną obliczono i wyrażono jako stosunek ilości wydzielonego ciepła z kalorymetru semiadiabatycznego do ilości wydzielonego ciepła z kalorymetru izotermicznego, dla danego rodzaju cementu i dla danego okresu hydratacji. Porównując współczynniki korelacji badanych cementów, należy podkreślić ich zróżnicowanie dla poszczególnych rodzajów cementów. Wielkość współczynnika korelacji dla cementów portlandzkich CEM I i cementów portlandzkich wieloskładnikowych CEM II maleje z czasem hydratacji. W przypadku cementu hutniczego CEM III obserwujemy wzrost wielkości współczynnika korelacji w przedziale czasowym ok. 24–48 godzin.
The main goal of this work was the determination of the correlation coefficient, between results of the heat of hydration measurements carried out using isothermal method and semi-adiabatic method according to PN-EN 196-9. It should be underlined, that that correlation exists for results of heat of hydration after 41 hours semi-adiabatic method according to PN-EN 196-9 and solution method after 168 hours according to PN-EN 196-8. The comparative studies of heat of hydration by isothermal method and semi-adiabatic method according to PN-EN 196-9 and the determination of the correlation coefficient, between these methods, were carried out with using of the selected industrial cements differentiated by their type, the content of cement addition and its degree of fineness. The correlation coefficients between semi-adiabatic and isothermal methods were calculated and expressed as the ratio of the cumulated heat of hydration from semi-adiabatic calorimeter to the cumulated heat of hydration from isothermal calorimeter, for particular cement and hydration period. Comparing the correlation coefficients of studied cements, their differentiation for particular cement types should be underlined. The value of the correlation coefficient for Portland cements CEM I and Portland cements with additions CEM II decreases over the hydration time. However, in the case of blast-furnace cement, the increase of the correlation coefficient value in time interval about 24–48 hours is observed.
Źródło:
Prace Instytutu Ceramiki i Materiałów Budowlanych; 2017, R. 10, nr 29, 29; 7-17
1899-3230
Pojawia się w:
Prace Instytutu Ceramiki i Materiałów Budowlanych
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterisation of Selected Emulsion Phase Parameters in Milk, Cream and Buttermilk
Autorzy:
Brożek, Oskar
Kiełczewska, Katarzyna
Bohdziewicz, Krzysztof
Powiązania:
https://bibliotekanauki.pl/articles/2016033.pdf
Data publikacji:
2022-03-01
Wydawca:
Instytut Rozrodu Zwierząt i Badań Żywności Polskiej Akademii Nauk w Olsztynie
Tematy:
milk products
size of fat globules
fatty acid profile
differential scanning calorimetry curves
differential scanning calorimetry parameters
Opis:
Milk fat undergoes modification during butter production, which can alter its parameters and suitability for processing. The aim of this study was to compare selected milk fat parameters, including the size of milk fat globules, fatty acid profile and thermal properties, based on the thermal history of milk, cream and sweet buttermilk obtained during continuous churning in butter production. The size of milk fat globules was measured by the laser diffraction method; the fatty acid profile of milk fat was determined by gas chromatography; and the thermal properties of freeze-dried samples were determined by differential scanning calorimetry. The analysed products were arranged in the following descending order based on the size of milk fat globules, expressed by the Sauter mean diameter: cream > raw milk > buttermilk. Buttermilk was characterised by the greatest variations in the size of milk fat globules. A microscopic analysis revealed that an increase in fat content intensified the agglomeration of milk fat globules in cream rela tive to milk. Chains of milk fat globules were observed in buttermilk. Buttermilk was more abundant in monoenoic and polyenoic fatty acids than raw milk and cream. A thermal analysis demonstrated significant ( p≤0.05) differences in the parameters of fat crystallisation and melting peaks between raw milk, buttermilk and cream. The thermal history of the samples influenced the results. Cream was characterised by significantly greater changes in the melting and crystallisation enthalpy of milk fat and significantly higher peak s than milk and buttermilk.
Źródło:
Polish Journal of Food and Nutrition Sciences; 2022, 72, 1; 5-15
1230-0322
2083-6007
Pojawia się w:
Polish Journal of Food and Nutrition Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis and Characterization of the Energetic Compounds Aminoguanidinium-, Triaminoguanidiniumand Azidoformamidinium Perchlorate
Autorzy:
Klapötke, T. M.
Stierstorfer, J.
Powiązania:
https://bibliotekanauki.pl/articles/358855.pdf
Data publikacji:
2008
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
perchlorates
energetic salts
calorimetry
X-ray
DSC
Opis:
Aminoguanidinium perchlorate (2, AGClO4) was formed by the reaction of aminoguanidinium bicarbonate (1) with aqueous perchloric acid solution. Triaminoguanidinium perchlorate (3, TAGClO4) was synthesized by nucleophilic attack of aqueous hydrazine solution on aminoguanidinium perchlorate under release of ammonia. The new and highly explosive azidoformamidinium perchlorate (4, AFClO4) was formed by the reaction of aminoguanidinium perchlorate with potassium nitrite under acidic conditions. The structures of the perchlorate salts in the crystalline state were determined using low temperature single crystal X-ray diffraction yielding monoclinic as well as orthorhombic structures. The compounds were characterized comprehensively using vibrational spectroscopy (IR and Raman), multinuclear (1H, 13C and 15N) NMR spectroscopy, elemental analysis and mass spectrometry. The thermal behavior as well as the decompositions were investigated using DSC (differential scanning calorimetry) and the heats of formation were calculated using heats of combustion determined by bomb calorimetric measurements. In addition, the sensitivities were evaluated using BAM methods (drophammer and friction tester), whereby the perchlorate salts are all sensitive towards impact as well as friction.
Źródło:
Central European Journal of Energetic Materials; 2008, 5, 1; 13-30
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of sample preparation and the presence of other active pharmaceutical ingredients (api) and excipients on the use of dsc method in quantification of paracetamol in commercially available tablets
Autorzy:
TALIK, Przemysław
TALIK, Piotr
HUBICKA, Urszula
Powiązania:
https://bibliotekanauki.pl/articles/1033708.pdf
Data publikacji:
2016
Wydawca:
Zakład Opieki Zdrowotnej Ośrodek Umea Shinoda-Kuracejo
Tematy:
"DSC"
"Differential Scanning Calorimetry"
"acetaminophen"
"ibuprofen"
"paracetamol"
Opis:
The direct Differential Scanning Calorimetry method of the determination of paracetamol in commercially available drugs was developed. The method was based on calibration curves obtained from melting enthalpies ΔH of binary mixtures of paracetamol and commonly used excipients such as starch or microcrystalline cellulose in increasing weight ratios. In order to demonstrate how the technological processes of formulating the tablets affects the quantitative studies, the micronized and nonmicronized mixtures were used. The idea of using micronized mixtures was to simulate these technological processes. The appropriate paracetamol contents of the selected pharmaceutical preparations were calculated and compared. The final results demonstrated, that the contents of paracetamol obtained from micronized samples were much closer to those declared by the manufacturer than the nonmicronized. Excluding two drugs, the influence of starch or cellulose on quantification in the micronized group was not observed whereas in the nonmicronized group it was distinctly visible.
Źródło:
Medicina Internacia Revuo; 2016, 27, 107; 100-106
0465-5435
Pojawia się w:
Medicina Internacia Revuo
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Calorimetric Measurements of Ga-Li System by Direct Reaction Method
Autorzy:
Dębski, A.
Powiązania:
https://bibliotekanauki.pl/articles/350810.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
gallium-lithium system
Ga-Li
calorimetry
thermochemistry
Opis:
The direct reaction calorimetric method was used for the determination of the formation enthalpy of alloys which concentrations correspond to the: Ga7Li2, Ga9Li5, GaLi, Ga4Li5, Ga2Li3, and GaLi2 intermetallic phases. The obtained experimental values of the formation enthalpy were: –18.1 ±0.8 kJ/mol at., –26.5 ±0.3 kJ/mol at., –34.7 ±0.3 kJ/mol at., –33.5 ±0.5 kJ/mol at., –32.8 ±0.3 kJ/mol at. and –24.6 ±1.4 kJ/mol at., respectively. After the calorimetric measurements, all the samples were checked by way of X-ray diffraction investigations to confirm the structure of the measured alloys. All the measured values of the formation enthalpy of the Ga-Li alloys were compared with literature data and the data calculated with use of the Miedema model.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2A; 919-926
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermochemical characterization of Ca4La6(SiO4)6(OH)2 a synthetic La- and OH-analogous of britholite: implication for monazite and LREE apatites stability
Autorzy:
Janots, Emilie
Brunet, Fabrice
Goffe, Bruno
Poinssot, Christophe
Burchard, Michael
Cemic, Lado
Powiązania:
https://bibliotekanauki.pl/articles/2086520.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Mineralogiczne
Tematy:
monazite
britholite
apatite
calorimetry
nuclear waste form
Opis:
In this contribution, monazite (LREEPO4) solubility is addressed in a chemical system involving REE-bearing hydroxylapatite, (Ca,LREE)10(PO4,SiO4)6(OH)2. For this purpose, a synthetic (La)- and (OH)-analogous of britholite, Ca4La6(SiO4)6(OH)2, was synthesised and its thermodynamic properties were measured. Formation enthalpy of –14,618.4 ± 31.0 kJ·mol–1 was obtained by high-temperature drop-solution calorimetry using a Tian-calvet twin calorimeter (Bochum, Germany) at 975 K using lead borate as solvent. Heat capacities (Cp) were measured in the 143–323 K and 341–623 K ranges with an automated Perkin-Elmer DSC 7. For calculations of solubility diagrams at 298 K, the GEMS program was used because it takes into account solid solutions. In conditions representative of those expected in nuclear waste disposal, calculations show that La-monazite is stable from pH = 4 to 9 with a minimum of solubility at pH = 7. La-bearing hydroxylapatite precipitates at pH > 7 with a nearly constant composition of 99% hydroxylapatite and 1% La-britholite. Each mineral buffers solution at extremely low lanthanum concentrations (log{La} = 10–10–10–15 mol·kg–1 for pH = 4 to 13). In terms of chemical durability, both La-monazite and La-rich apatite present low solubility, a requisite property for nuclear-waste forms.
Źródło:
Mineralogia; 2008, 39, 1/2; 41--52
1899-8291
1899-8526
Pojawia się w:
Mineralogia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermochemical characterization of Ca4La6(SiO4)6(OH)2 a synthetic La- and OH-analogous of britholite: implication for monazite and LREE apatites stability
Autorzy:
Janots, E.
Brunet, F.
Goffe, B.
Poinssot, C.
Burchard, M.
Cemic, L.
Powiązania:
https://bibliotekanauki.pl/articles/2086546.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Mineralogiczne
Tematy:
monazite
britholite
apatite
calorimetry
nuclear waste form
Opis:
In this contribution, monazite (LREEPO4) solubility is addressed in a chemical system involving REE-bearing hydroxylapatite, (Ca,LREE)10(PO4,SiO4)6(OH)2. For this purpose, a synthetic (La)- and (OH)-analogous of britholite, Ca4La6(SiO4)6(OH)2, was synthesised and its thermodynamic properties were measured. Formation enthalpy of –14,618.4 ± 31.0 kJ·mol–1 was obtained by high-temperature drop-solution calorimetry using a Tian-calvet twin calorimeter (Bochum, Germany) at 975 K using lead borate as solvent. Heat capacities (Cp) were measured in the 143–323 K and 341–623 K ranges with an automated Perkin-Elmer DSC 7. For calculations of solubility diagrams at 298 K, the GEMS program was used because it takes into account solid solutions. In conditions representative of those expected in nuclear waste disposal, calculations show that La-monazite is stable from pH = 4 to 9 with a minimum of solubility at pH = 7. La-bearing hydroxylapatite precipitates at pH > 7 with a nearly constant composition of 99% hydroxylapatite and 1% La-britholite. Each mineral buffers solution at extremely low lanthanum concentrations (log{La} = 10–10–10–15 mol·kg–1 for pH = 4 to 13). In terms of chemical durability, both La-monazite and La-rich apatite present low solubility, a requisite property for nuclear-waste forms.
Źródło:
Mineralogia; 2008, 39, 1/2; 41--52
1899-8291
1899-8526
Pojawia się w:
Mineralogia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of thermal analysis and calorimetry for assessment of safety and quality of nitrogen fertilizers
Autorzy:
Poplawski, D.
Kaniewski, M.
Hoffmann, J.
Hoffmann, K.
Powiązania:
https://bibliotekanauki.pl/articles/30147054.pdf
Data publikacji:
2018
Wydawca:
Akademia Wojsk Lądowych imienia generała Tadeusza Kościuszki
Tematy:
ammonium nitrate
fertilizers
safety
quality
calorimetry
thermal analysis
Opis:
The paper presents the results of studies carried out using differential thermal analysis (DTA) and differential scanning calorimetry (DSC), conjugated with thermogravimetry (TG). Measurements were made for samples with differentiated compositions, mainly consisting of ammonium nitrate with fertilizer purity and compounds that may be present in nitrogen fertilizers as potential additives or contaminants. The possibilities of applied techniques and recommendations concerning proper selection of measurement conditions are described. Furthermore, the method of interpretation of the obtained results is presented, which allows evaluating the thermal stability of the tested mixtures for the safety and quality of nitrogen fertilizers.
Źródło:
Scientific Journal of the Military University of Land Forces; 2018, 50, 3(189); 206-217
2544-7122
2545-0719
Pojawia się w:
Scientific Journal of the Military University of Land Forces
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis and thermal decomposition study of some dihydropyridine derivatives
Autorzy:
Baluja, Shipra
Talaviya, Rahul
Powiązania:
https://bibliotekanauki.pl/articles/1192993.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
differential scanning calorimetry
dihydropyridine derivatives
thermo gravimetric analysis
Opis:
Some new dihydropyridine derivatives have been synthesized and their characterization was done by FT-IR, 1H NMR and Mass spectral data. Thermal analysis of these dihydropyridine derivatives have been carried out by thermao gravimetric (TG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC) techniques. Further, from thermograms of these compounds, various kinetic parameters such as order of reaction (n), energy of activation (E), frequency factor (A) and entropy change (∆S) have been evaluated. The obtained results indicates that thermal stability of dihydropyridine derivatives have been depend on the type of substituent present in the compounds.
Źródło:
World Scientific News; 2016, 39; 1-16
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Purification of Hexabenzylhexaazaisowurtzitane
Autorzy:
Gołofit, T.
Maksimowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/358605.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
HBIW
CL-20
purification
differential scanning calorimetry
cryometric method
Opis:
Hexabenzylhexaazaisowurtzitane (HBIW) is produced by a condensation reaction of benzylamine with glyoxal in suitable organic solvents in the presence of protonic acid catalysts. Impurities have to be removed prior to the subsequent stages of the synthesis of CL-20. The effectiveness of HBIW purification by recrystallization from a variety of solvents has been studied here. This method was compared with a novel approach suggested for HBIW purification that consists of prolonged heating of the crude product in boiling methanol. This new purification method allows the product to be prepared in satisfactory purity, it is simple and easily performed on a large-scale.
Źródło:
Central European Journal of Energetic Materials; 2016, 13, 4; 1038-1050
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analiza termo-optyczna (TOA) jako narzędzie badań zjawisk topnienia
Thermo-optical analysis (TOA) as a tool of melting phenomena investigations
Autorzy:
Galewski, Zbigniew
Korbecka, Izabela
Osiecka-Drewniak, Natalia
Powiązania:
https://bibliotekanauki.pl/articles/171758.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
kalorymetria adiabatyczna
kalorymetria DSC z kompensacją ciepła
kalorymetria DSC z przepływem ciepła
modulacyjna kalorymetria
MDSC
różnicowa analiza termiczna
DTA
ciekłe kryształy
mezogeny
fazy rotacyjne
adiabatic calorimetry
DSC calorimetry with heat compensation
DSC calorimetry with heat flow
modulation calorimetry
differential thermal analysis
liquid crystals
mesogens
rotational phases
Opis:
In the work, after preliminary discussion of the complexity of the phenomenon of melting chemical compounds, two basic research methods are presented: calorimetric methods and thermooptical method. The physical basis of the five main calorimetry techniques is now detailed (adiabatic calorimetry, differential thermal analysis – DTA, differential scanning calorimetry with heat compensation – DSC heat compensated, differential scanning calorimetry with heat flow – DSC heat flux and differential scanning calorimetry with temperature modulation – MDSC) and thermo-optical techniques used in phase transitions investigations. The advantages and disadvantages of these methods are shown in numerous examples and the accuracy attainable by the individual measuring techniques is compared.
Źródło:
Wiadomości Chemiczne; 2019, 73, 3-4; 202-220
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermogravimetric biomass-to-liquid processes
Autorzy:
Rostek, E.
Biernat, K.
Powiązania:
https://bibliotekanauki.pl/articles/242234.pdf
Data publikacji:
2011
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
biomass
gasification
Thermogravimetric Analysiss
differential scanning calorimetry (DSC)
enthalpy
Opis:
The article presented forecasts for European biofuel production in processes BtL and WtL on the basis of thermochemical technological path. The paper presents the processes of pyrolysis and gasification of biomass leading to the preparation of liquid hydrocarbon fractions in the synthesis of Fischer-Tropsch and processes HTU. Based on the model Koufopanosa, made the right choice of methods to investigate the thermogravimetric kinetics of biomass gasification with a change of enthalpy and identification of degradation products in real time. Presents the results of preliminary tests conducted on the Simultaneous Thermal Analyzer STA 449 F3 Jupiter's Nietzsche. These studies were carried out for samples of cereal straw, crushed to a state of dry dust. Gasification process by subjecting the sample, the test set, recorded curves TG and DSC, and observing the changes in mass, temperature and enthalpy. These studies have been done to pre-determine the conditions under which it may begin the process of liquidation. The study was conducted in an atmosphere of argon / nitrogen and argon / carbon dioxide. The temperature regime provided that the samples were heated to the temperature of500 °C at the heating rate of 3 K/min. Argon was used as protective gas, and N2 and CO2 - as purge gas with flow rates of 30 ml/min. The results, along with discussion, are presented in graphs -derivatograms and charts showing the cumulative weight changes and changes in enthalpy of individual samples.
Źródło:
Journal of KONES; 2011, 18, 2; 377-383
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermodynamics of specific protein-RNA interactions.
Autorzy:
Stolarski, Ryszard
Powiązania:
https://bibliotekanauki.pl/articles/1043600.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
calorimetry
thermodynamics
fluorescence
proteins
specific binding
RNA 5' cap
Opis:
Description of the recognition specificity between proteins and nucleic acids at the level of molecular interactions is one of the most challenging tasks in biophysics. It is key to understanding the course and control of gene expression and to the application of the thus acquired knowledge in chemotherapy. This review presents experimental results of thermodynamic studies and a discussion of the role of thermodynamics in formation and stability of functional protein-RNA complexes, with a special attention to the interactions involving mRNA 5' cap and cap-binding proteins in the initiation of protein biosynthesis in the eukaryotic cell. A theoretical framework for analysis of the thermodynamic parameters of protein-nucleic acid association is also briefly surveyed. Overshadowed by more spectacular achievements in structural studies, the thermodynamic investigations are of equal importance for full comprehension of biopolymers' activity in a quantitative way. In this regard, thermodynamics gives a direct insight into the energetic and entropic characteristics of complex macromolecular systems in their natural environment, aqueous solution, and thus complements the structural view derived from X-ray crystallography and multidimensional NMR. Further development of the thermodynamic approach toward interpretation of recognition and binding specificity in terms of molecular biophysics requires more profound contribution from statistical mechanics.
Źródło:
Acta Biochimica Polonica; 2003, 50, 2; 297-318
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of differential scanning calorimetry to the study of thermodynamic properties of food proteins, particularly of poultry, red meat and egg proteins
Zastosowanie różnicowej kalorymetrii skaningowej do badania termodynamicznych właściwości białek żywności, ze szczególnym uwzględnieniem białek mięsa, drobiu i jaj
Autorzy:
Kijowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1399641.pdf
Data publikacji:
1989
Wydawca:
Instytut Rozrodu Zwierząt i Badań Żywności Polskiej Akademii Nauk w Olsztynie
Tematy:
differential canning calorimetry
thennodynamic parameters
food proteins
poultry
meat
egg
Opis:
The paper reviews some aspects of differential scanning calorimetry (DSC) and application of this technique in the food protein study, mainly poultry, red meat and egg proteins. Thermodynamic data as the onset, maximum temperature and enthalpy transition of heated protein systems can yield valuable information regarding intrinsic structure stability, protein-protein protein- the other component interaction and denaturation behaviour. DSC can be useful in characterising protein damage in food subjected to a wide range of treatment and proces ing. DSC parameter can indirectly aid in the optimisation and control of different processe such as storage and cooking.
Na przykładzie białek mięsa drobiu i bydła pokazano możliwość wykorzystania RKS do optymalizacji i kontroli procesów obróbki cieplnej. Pokazano również możliwość śledzenia wpływu dodatku NaCl i fosforanów na stabilność cieplną białek mięśniowych. Na przykładzie białek jaja wskazano możliwość śledzenia interakcji białek z białkami (owomukoid-trypsyna), białka z witaminami (awidyna-biotyna), stabilizacji cieplnej konalbuminy w wyniku interakcji z metalami i sacharozą.
Źródło:
Acta Alimentaria Polonica; 1989, 15(39), 4; 299-315
0137-1495
Pojawia się w:
Acta Alimentaria Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis and Study of the Thermal and Ballistic Properties of SMX
Autorzy:
Sizov, V. A.
Pleshakov, D. V.
Asachenko, A. F.
Topchiy, M. A.
Nechaev, M. S.
Powiązania:
https://bibliotekanauki.pl/articles/358831.pdf
Data publikacji:
2018
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
tetranitrate ester
burning rate
differential scanning calorimetry
decomposition
thermogravimetric analysis
Opis:
The high-density tetranitrate ester 1,4-dinitrato-2,3-dinitro-2,3-bis(nitratomethylene)butane (SMX) was synthesized. The methods of obtaining and isolating the intermediates were optimized. The differences between the syntheses of SMX by a four- and five-step scheme were investigated. Combustion of SMX and its catalysis was studied. The possibility of replacing NG as the main plasticizer in a double-base propellant composition was demonstrated. SMX particles were shown to have pronounced crystal faceting using scanning electron microscopy. The decomposition rate equation was determined. The amount of SMX decomposed under isothermal conditions (90 °C) was 0.8 wt.% after 60 min. Thermogravimetric analysis demonstrated that heating SMX results in two different processes – decomposition and evaporation, with SMX evaporating faster than it decomposes.
Źródło:
Central European Journal of Energetic Materials; 2018, 15, 1; 30-46
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enthalpy of formation of intermetallic phases from Fe-Ni-Ti System. Comparative studies
Entalpia tworzenia faz międzymetalicznych z układu Fe-Ni-Ti. Studia porównawcze
Autorzy:
Gąsior, W.
Dębski, A.
Powiązania:
https://bibliotekanauki.pl/articles/356183.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
intermetallics
phase diagrams
thermodynamic and thermochemical properties
phase identification
calorimetry
Opis:
The solution calorimetric method was used for the measurement of the formation enthalpy of the binary FeTi and Fe2Ti intermetallic phases and of the FeNiTi2 phase from the region of the ternary B2 one. The FeNi and FeNiTi2 phases were prepared by levitation melting and the Fe2Ti phase - by melting the metals in a glove-box under high purity argon. The alloys obtained were identified by the X-ray diffraction analysis. The structural study of the alloys with the composition equal to the FeTi and Fe2Ti phase confirmed the mentioned phases mainly in the samples. In the case of the ternary alloy of the composition of the FeNiTi2 phase, a slight amount of iron was also found. The obtained values of the formation enthalpy equal as follows: -27.2±1.3 kJ/mole of atoms, -22.5±1.4 kJ/mole of atoms and -34.2±1.3 kJ/mole of atoms for the Fe2Ti, FeTi and FeNiTi2 phase, respectively.
Stosując kalorymetryczna metodę rozpuszczania zostały zmierzone entalpie tworzenia dwóch dwuskładnikowych faz międzymetalicznych FeTi i Fe2Ti oraz z obszaru fazy trójskładnikowej B2. Fazy FeTi i FeNiTi2 zostały przygotowane metoda lewitacyjnego topienia a faza Fe2Ti metoda metalurgiczna przez stopienie metali w komorze manipulacyjnej z atmosfera ochronna argonu wysokiej czystości. Otrzymane stopy były poddane identyfikacji metoda analizy dyfrakcji promieniowania rentgenowskiego. Badania te potwierdziły występowanie w próbkach dwuskładnikowych głównie faz FeTi i Fe2Ti. W przypadku stopu trójskładnikowego oprócz fazy FeNiTi2 została wykryta niewielka ilość żelaza. Zmierzone wartości entalpii tworzenia faz wynoszą: -27.2±1.3 kJ/mol atomów dla Fe2Ti, -22.5±1.4 kJ/mol atomów dla FeTi oraz -34.2±1.3 kJ/mol atomów dla FeNiTi2.
Źródło:
Archives of Metallurgy and Materials; 2012, 57, 4; 1095-1104
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase Stability of Ammonium Nitrate with Organic Potassium Salts
Autorzy:
Xu, Z.-X.
Fu, X.-Q.
Wang, Q.
Powiązania:
https://bibliotekanauki.pl/articles/358264.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
ammonium nitrate(V)
phase transition
organic compounds
differential scanning calorimetry
Opis:
A study has been undertaken on the effect of additives on the phase transition of ammonium nitrate(V) (AN). Results obtained using Differential Scanning Calorimetry (DSC) showed that organic compounds and potassium salts of organic compounds have an effect on the phase transition behavior of AN. The samples were further analyzed using infrared (IR) and powder X-ray diffraction (XRD). The mechanism of phase stabilization of AN by compounds of this kind was examined. The present study showed that the influence of additives on the phase transition of AN occurs through the polar groups that are involved in intermolecular interactions of orbital and electrostatic types that form new hydrogen bonds. AN exists in only one phase in the temperature range from 30 °C to +100 °C, when a potassium salt of organic compounds was added. However, with organic compounds, the III→II phase transition was changed. IR and XRD of composites are characterized by new intermolecular interactions. Compacted samples of AN containing potassium salts of organic compounds exhibited better stability than AN containing organic compounds to multiple cyclic changes within a temperature range. This we named ‘freezing and thawing analysis’. Additives have two functions on the AN phase transition. First, solid solutions of AN mixture were formed for K+ replacement of NH4+. Second, hydrogen bonds formed, which caused AN and salts of organic compounds to interact intimately.
Źródło:
Central European Journal of Energetic Materials; 2016, 13, 3; 736-754
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kinetics of Polymorphic Transitions in Energetic Compounds
Autorzy:
Chukanov, N. V.
Zakharov, V. V.
Korsunskiy, B. L.
Chervonnyi, A. D.
Vozchikova, S. A.
Powiązania:
https://bibliotekanauki.pl/articles/358796.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
polymorphic transitions
energetic compounds
molecular crystals
kinetics
calorimetry
IR spectroscopy
Opis:
Available data on the kinetics of polymorphic transitions (PTs) in energetic compounds under isothermal conditions are summarized and discussed. It is shown that the general kinetic regularities of these processes (stepwise and continuous regimes) depend on their topotactic mode (frontal or quasi-homogeneous, respectively). In reverse PTs, a nucleation stage is not observed, which is explained by the presence of nuclei of the low-temperature polymorph in the preheated sample. The influence of mechanical effects on the kinetics of PTs in molecular crystals is discussed.
Źródło:
Central European Journal of Energetic Materials; 2016, 13, 2; 483-504
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structure-function relationship of serine protease-protein inhibitor interaction.
Autorzy:
Otlewski, Jacek
Jaskólski, Mariusz
Buczek, Olga
Cierpicki, Tomasz
Czapińska, Honorata
Krowarsch, Daniel
Smalas, Arne
Stachowiak, Damian
Szpineta, Agnieszka
Dadlez, Michał
Powiązania:
https://bibliotekanauki.pl/articles/1044133.pdf
Data publikacji:
2001
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
calorimetry
serine proteases
structural thermodynamics
protein inhibitor
protein-protein recognition
Opis:
We report our progress in understanding the structure-function relationship of the interaction between protein inhibitors and several serine proteases. Recently, we have determined high resolution solution structures of two inhibitors Apis mellifera chymotrypsin inhibitor-1 (AMCI-I) and Linum usitatissimum trypsin inhibitor (LUTI) in the free state and an ultra high resolution X-ray structure of BPTI. All three inhibitors, despite totally different scaffolds, contain a solvent exposed loop of similar conformation which is highly complementary to the enzyme active site. Isothermal calorimetry data show that the interaction between wild type BPTI and chymotrypsin is entropy driven and that the enthalpy component opposes complex formation. Our research is focused on extensive mutagenesis of the four positions from the protease binding loop of BPTI: P1, P1', P3, and P4. We mutated these residues to different amino acids and the variants were characterized by determination of the association constants, stability parameters and crystal structures of protease-inhibitor complexes. Accommodation of the P1 residue in the S1 pocket of four proteases: chymotrypsin, trypsin, neutrophil elastase and cathepsin G was probed with 18 P1 variants. High resolution X-ray structures of ten complexes between bovine trypsin and P1 variants of BPTI have been determined and compared with the cognate P1 Lys side chain. Mutations of the wild type Ala16 (P1') to larger side chains always caused a drop of the association constant. According to the crystal structure of the Leu16 BPTI-trypsin complex, introduction of the larger residue at the P1' position leads to steric conflicts in the vicinity of the mutation. Finally, mutations at the P4 site allowed an improvement of the association with several serine proteases involved in blood clotting. Conversely, introduction of Ser, Val, and Phe in place of Gly12 (P4) had invariably a destabilizing effect on the complex with these proteases.
Źródło:
Acta Biochimica Polonica; 2001, 48, 2; 419-428
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of sodium hyaluronate on dehydration and water distribution in soft contact lenses
Autorzy:
Rajchel, D.
Krysztofiak, K.
Szyczewski, A.
Powiązania:
https://bibliotekanauki.pl/articles/174392.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
contact lens dehydration
sodium hyaluronate
gravimetry
differential scanning calorimetry (DSC)
Opis:
The purpose of this investigation was to examine the influence of sodium hyaluronate (HA) solution on contact lens dehydration and the distribution of water in lens materials. These parameters were measured with gravimetry and differential scanning calorimetry. Five commercial soft contact lenses were used. They represented four FDA (Federal Drug Administration) groups: Air Optix Night&Day Aqua and Acuvue Oasys (I FDA group), Proclear 1-Day (II FDA group), PureVision (III FDA group) and 1-Day Acuvue Moist (IV FDA group). All materials were investigated with two preservative-free HA solutions 0.1% and 0.3%. HA solutions influenced the water content and the dehydration rate of some examined lenses. For three lenses (Oasys, Proclear, Moist) water content of HA lenses was greater than control. Significant slowdown of dehydration rate under HA during the first 20min was observed only for Proclear. PhaseI of dehydration increased significantly with HA solutions in case of Moist and Proclear. For Night&Day and Oasys phaseI appeared under HA solution while it was not present for control lenses. Duration of the phaseI was strongly correlated with water content of the lenses (R2=0.844). The amount of freezable and non-freezable water depended strongly on characteristics of lens material and its interaction with HA molecules. Proclear seems to be the most prone to attach HA molecules which affect changes in dehydration characteristics and water behavior in the polymer. PureVision might be considered as the most resistant to HA in terms of dehydration dynamics and water distribution. All measured parameters seem to be dependent more on material properties than HA concentration.
Źródło:
Optica Applicata; 2016, 46, 3; 483-496
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of Thermoporometry Based on Convolutive DSC to Investigation of Mesoporosity in Cohesive Soils
Autorzy:
Kozłowski, T.
Babiarz, I.
Grobelska, E.
Powiązania:
https://bibliotekanauki.pl/articles/241378.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
pore distribution
thermoporometry
DSC (Differential Scanning Calorimetry)
montmorillonite
cohesive soils
Opis:
In the method of thermoporometry, the characterization of pore space is done by analysis of thermal effects associated with freezing and melting of a liquid in the pores of the material under investigation. Thermoporometry seems particularly well suited to studies of wet porous samples in cases where the process of drying itself is able to destroy the original microstructure, as is the cohesive soils containing montmorillonite. In the paper, a variant of thermoporometry is given in which the blurred calorimetric peak is processed by use of a stochastic-convolutive analysis. As a result, a "sharp" thermogram of real thermal effects is obtained which can be easily transformed into a pore distribution curve. The preliminary results, obtained for samples of three monoionic montmorillonites at different water contents, indicate a greater resolution, sensitivity and precision than the classical thermoporometry using an unprocessed DSC signal. Phenomena corresponding to swelling have been detected in two individual regions on the differential pore distribution curves. The first is a dense spectrum for pores less than 15 nm. The second is a single peak for pores greater than 15 nm. Between the two regions the distribution decays to zero. Apparently, the point of the single peak maximum depends on the total water content, shifting rightward with increasing w. For the region below 20 nm, a strong effect of the kind of exchangeable cation can be observed. The results suggest swelling in the form with bivalent cations (Ca-montmorillonite) and contraction in the form with monovalent cations (Na- and K-montmorillonite).
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2010, 57, 3-4; 199-218
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of conventional and crosslinked ultra high molecular weight polyethylene (UHMWPE) used in hip implant
Autorzy:
Laska, Anna
Powiązania:
https://bibliotekanauki.pl/articles/1178415.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Differential Scanning Calorimetry
acetabular cup
conventional UHMWPE
crosslinked UHMWPE
structural parameters
Opis:
Since the 1960s UHMWPE has been the material of choice for bearing surfaces in total hip replacements. In spite of its clinical success over years, a large number of necessary revisions has been recently reported. The clinical life span of the hip prostheses is limited by weardebris-induced osteolysis and aseptic loosening. The problem is very complex because of the variety of factors affecting UHMWPE. Nowadays, scientists are working on how optimally adjust the material properties and the implant design in order to increase wear resistance and retain other mechanical properties. The aim of the study is to investigate structural parameters of two UHMWPE material states – conventional (non-crosslinked) and crosslinked. Those types of UHMWPE show slightly different properties, which can affect further behaviour in human body. The comparison between conventional and crosslinked UHMWPE is presented. Differential Scanning Calorimetry (DSC) is the analysis method applied in the research. The structural parameters of UHMWPE are correlated with its mechanical and tribological properties.
Źródło:
World Scientific News; 2017, 73; 51-60
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal Degradation Behaviour and Kinetics of aged TNT-based Melt Cast Composition B
Autorzy:
Singh, Arjun
Sharma, Tirupati Chander
Singh, Vasundhara
Mukherjee, Niladri
Powiązania:
https://bibliotekanauki.pl/articles/358256.pdf
Data publikacji:
2019
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
composition B
thermal degradation
thermogravimetry
Differential Scanning Calorimetry
kinetics
thermodynamic parameters
Opis:
In the present paper, three kinds of aged and freshly prepared 2,4,6-trinitrotoluene (TNT) based Composition B stockpiled, for a period of 20 and 32 years, were investigated for the effect of natural ageing on their thermal degradation behaviour and kinetic parameters. The properties investigated indicated that there was no significant change in the thermal stability of the samples aged under natural environmental conditions. The kinetic parameters were studied by means of the Kissinger method using the peak temperature at maximum reaction rate from DSC data, and the isoconversional Kissinger-Akahira-Sunnose (KAS) and ASTM E689 methods from TGA data. The apparent activation energies calculated by the Kissinger method were 173.8 kJ·mol–1 for fresh, 170.4 kJ·mol–1 for 20 y old and 187.1 kJ·mol–1 for 32 y old Composition B, respectively. The values calculated by the KAS method were found to be in the range 77.2-235.8 kJ·mol–1 for fresh Composition B, 75.7-224.0 kJ·mol–1 for 20 y old and 70.4-196.0 kJ·mol–1 for 30 y old Composition B, respectively. The activation energies obtained from the KAS methods are in good agreement and consistent with the isoconversional ASTM E689 kinetic method. The thermodynamic parameters, such the Gibbs free energy of activation (ΔG#), activation enthalpy (ΔH#) and activation entropy (ΔS#) for the formation of activated complexes were also studied and are discussed.
Źródło:
Central European Journal of Energetic Materials; 2019, 16, 3; 360-379
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
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