•The extent of the replacement was improved due to the enclathration of N2 in small cages.•The dissociation enthalpies of the replaced gas hydrates were measured.•There was no noticeable heat flow ...change during the CH4–flue gas replacement.•The replacement could occur without significant destruction of gas hydrates.
The CH4–flue gas replacement in naturally occurring gas hydrates has attracted significant attention due to its potential as a method of exploitation of clean energy and sequestration of CO2. In the replacement process, the thermodynamic and structural properties of the mixed gas hydrates are critical factors to predict the heat flow in the hydrate-bearing sediments and the heat required for hydrate dissociation, and to evaluate the CO2 storage capacity of hydrate reservoirs. In this study, the 13C NMR and gas composition analyses confirmed that the preferential enclathration of N2 molecules in small 512 cages of structure I hydrates improved the extent of the CH4 recovery. A high pressure micro-differential scanning calorimeter (HP μ-DSC) provided reliable hydrate stability conditions and heat of dissociation values in the porous silica gels after the replacement, which confirmed that CH4 in the hydrates was successfully replaced with flue gas. A heat flow change associated with the dissociation and formation of hydrates was not noticeable during the CH4–flue gas replacement. Therefore, this study reveals that CH4–flue gas swapping occurs without structural transitions and significant hydrate dissociations.
This study aims at providing a formidable solution to rapid increasing building energy demands. It projects Phase Change Material (PCM) incorporated bricks as a passive solution for cooling load ...abatement. The PCMs for this research are selected based on their thermal characteristics through Differential Scanning Calorimeter (DSC) and climatic conditions of the place. In this study, the experimental testing of PCM bricks under actual conditions, followed by, assessing the impact of various PCM configurations is carried out. The experiments are carried out for peak summer conditions, with ambient temperature above 40 °C, during the day. The temperature reduction of 4 °C–9.5 °C is observed across single and dual PCM layer bricks, compared to the conventional ones. The heat transfer reduction between 40% and 60% is observed, during the day. These bricks are also used to determine the effect of increasing the PCM thickness and using it in combination with fins, to assess the impact in terms of temperature and heat transfer to the inside surface. However, the results showed that using fins has a detrimental impact on temperature and heat flow.
•Projecting PCM bricks as a sustainable building solution for passive conditioning.•DSC based PCM selection for a particular climatic condition.•Thermal assessment of PCM incorporated bricks with variable PCM thickness.•Effect of fins within a PCM incorporated brick.
The ICALIC project was initiated for developing an accurate, reliable and user friendly indirect calorimeter (IC) and aimed at evaluating its ease of use and the feasibility of the EE measurements in ...intensive care unit (ICU).
This was a prospective unblinded, observational, multi-center study. Simultaneous IC measurements in mechanically ventilated ICU patients were performed using the new IC (Q-NRG®) and currently used devices. Time required to obtain EE was recorded to evaluate the ease of use of Q-NRG® versus currently used ICs and EE measurements were compared. Conventional descriptive statistics were used: data as mean ± SD.
Six centers out of nine completed the required number of patients for the primary analysis. Mean differences in the time needed by Q-NRG® against currently used ICs were −32.3 ± 2.5 min in Geneva (vs. Deltatrac®; p < 0.01), −32.3 ± 3.1 in Lausanne (vs. Quark RMR®; p < 0.05), −33.7 ± 1.4 in Brussels (vs. V-Max Encore®; p < 0.05), −26.4 ± 7.8 in Tel Aviv (vs. Deltatrac®; p < 0.05), −28.5 ± 3.5 in Vienna (vs. Deltatrac®; p < 0.05), and 0.3 ± 1.2 in Chiba (vs. E-COVX®; p = 0.17). EE (kcal/day) measurements by the Q-NRG® were similar to the Deltatrac® in Geneva and Vienna (mean differences±SD: −63.1 ± 157.8 (p = 0.462) and −22.9 ± 328.2 (=0.650)), but significantly different in Tel Aviv (307.4 ± 324.5, p < 0.001). Significant differences were observed in Lausanne (Quark RMR®: −224.4 ± 514.9, p = 0.038) and in Brussels (V-max®: −449.6 ± 667.4, p < 0.001), but none was found in Chiba (E-COVX®; 55.0 ± 204.1, p = 0.165).
The Q-NRG® required a much shorter time than most other ICs to determine EE in mechanically ventilated ICU patients. The Q-NRG® is the only commercially available IC tested against mass spectrometry to ensure gas accuracy, while being very easy-to use.
Thermal safety assessment for solid organic peroxides Liu, Shang-Hao; Wang, Yan-Ru; Xiong, Cheng-Lei ...
Journal of loss prevention in the process industries,
November 2020, 2020-11-00, Letnik:
68
Journal Article
Recenzirano
The thermal hazards of dicumyl peroxide (DCP) and benzoyl peroxide (BPO), self-reactive chemicals are identified and characterized using high-pressuredifferential scanning calorimeter, and ...simultaneous thermogravimetric analyzer, a C80 micro-calorimeter is used. The apparent exothermic onset temperature of DCP is found to be between the range of 112–122 °C for different heating rates in DSC tests. There are two coupled peaks of BPO around 105 °C at both the heating rates of 4.0 and 8.0 °C/min while no endothermic peak showed at lower heating rates. Furthermore, another endothermic peak appears immediately after the exothermic peak at about 211 °C of DCP under high-pressure conditions. For BPO, the endothermic peak before the exothermic peak disappears as the pressure increases to 1.0 and 1.5 MPa. The average values of apparent activation energy calculated by Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose methods during the conversion rate between 15 and 75% of DCP are 80.69 and 74.05 kJ/mol, and that of BPO are 119.96 and 112.93 kJ/mol, respectively. According to the isothermal tests, the thermal decomposition of DCP behaviors is an n-th order reaction while BPO conforms to the laws of autocatalytic reaction.
●The thermal decomposition of dicumyl peroxide and benzoyl peroxide under 0.5, 0.75, 1.0, and 1.5 MPa was measured.●The average values of apparent activation energy were calculated.●The thermal decomposition of DCP behaviors is an n-th order reaction while BPO conforms to the laws of autocatalytic reaction.
Starch from a given botanical source can vary considerably in terms of physicochemical properties in its native and hydrolyzed forms. The current study investigated the structural and functional ...characteristics of starch from ten indigenous rice varieties endemic to Northeast India. In vitro enzymatic hydrolysis was used to reveal the dextrose equivalent profile of each type of starch. Gezep Sali and Betguti Sali respectively exhibited the highest and lowest starch hydrolysis. Among the ten rice varieties, amylose content varied between 7.50 and 28.58%. Optical and scanning electron microscopy (SEM) revealed the polyhedral shape of the native starch granules and deformation of the shape upon enzymatic hydrolysis. Second harmonic generation (SHG) microscopy and X-ray diffraction (XRD) analysis confirmed the presence of and variations in starch crystallinity. XRD revealed spectral peaks characteristic of A-type starch crystals in the native form. The elevated intensity of XRD peaks in hydrolyzed starch granules confirmed the occurrence of amylose hydrolysis rather than hydrolysis in amylopectin regions. Fourier transform infrared (FTIR) spectra revealed the common stretching and bending of bonds in all native starches; however, changes were observed in the fingerprint region (1080, 1000, 926 cm−1) of hydrolyzed starch granules, which indicates the amylolysis of the amylose region and disturbances in the ordered arrangement in the crystalline part. Differential scanning calorimeter (DSC) endotherms revealed the highest and lowest gelatinization peak temperatures in Harfoni (78 °C) and Tulosi Sali (41 °C) rice cultivars, respectively. The findings in this study can help to optimize the usage of rice starch in food and non-food industries. Furthermore, understanding the control points of starch digestion and genetically tailoring rice grains with different digestibility could be beneficial for nutraceutical applications.
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•Amylose and amylopectin ratio determines in-vitro digestion of native rice starch.•Native starch granules are polyhedral shaped which is demorphed upon enzymolysis.•SHG microscopy and XRD respectively visualizes and studies the molecular structure of crystalline domains.•FTIR spectroscopy confirmed the changes at 1000 cm-1 corresponds to amylose and amylopectin region.•DSC analysis revealed the inverse correlation of amylose and gelatinization temperature.
During pharmaceutical or biopharmaceutical drug product development, one of the most important steps to be followed is characterization and reverse engineering of the drug product. Out of so many ...characterization tools and orthogonal reverse engineering techniques, thermoanalytical methods are the most useful techniques. Different thermoanalytical techniques are used to identify, quantify and understand the interaction between different polymorphic forms of drug substances and excipients. These techniques are also used to monitor the physical form (amorphous or crystalline) of the drug substance in drug product throughout its manufacturing processes and helps in identifying, omitting or modifying the steps or processes responsible for change in physical or polymorphic form of the drug substance in the finished drug product. Thermoanalytical techniques are not only useful for characterization of small molecules but also extensively applied in analysis of biological samples and nano-formulations. In current scenario, pharmaceutical development specifically during generic drug development the most useful step is the reverse engineering. When reverse engineering of drug product is concerned, thermoanalytical techniques are the best tools to be used to prove the similarity of physico-chemical properties or same state of matter or arrangement of matter between test and reference products. However, in earlier days these techniques were not used as frequently as the other techniques like spectroscopy and chromatography. Various reasons for limited use of thermoanalytical techniques were unavailability of software or compatible hardware, manual sampling process and a tedious process of manual calculation which consumes lots of time. Now a day, due to advancement of technology, automation, use of robotics, and better understanding, and the thermal analysis not only become a powerful tool but also increase the throughput. The present review focuses on some of the most commonly used Thermoanalytical techniques e.g. Differential Scanning Calorimeter (DSC), Thermogravimetric Analysis (TGA), Solution Calorimeter (SC), Thermo Mechanical Analysis (TMA) and Isothermal Titration Calorimeter (ITC) for characterization and reverse engineering of different dosage forms like solid oral dosage forms, injectable formulation, inhalation formulation, ophthalmic formulation, and biosimilar formulation products such as peptides and proteins using specific case studies.
Accurate and reliable estimation of specific growth rate (μ) in real-time is pivotal for reliable process monitoring of a bioprocess and subsequent implementation of advanced control strategies. ...Gibbs free energy dissipation is imminent for any biological system, and the metabolic heat flow measurements (calorimetry) formed the basis for estimating μ. However, the rationale behind selecting a suitable μ estimator model based on calorimetric perspective remains unexplored. The present investigation addresses the notion behind the selection of an appropriate estimator for μ and the assessment of the estimator models was illustrated using different types of energy metabolism, namely, high exothermic and low exothermic processes. The results indicated that the μ values from the instantaneous heat flow estimator significantly deviated (10-fold higher) from the offline values for highly exothermic process. Notably, the cumulative heat-based estimator accurately estimated μ values on both types of energy metabolism with performance metrics <0.005 h−1.
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► History of the development of the chip XI-400 is described. ► Performance of the chip in the instrument is explained from a device point of view. ► Thermal lag aspects of the chip are introduced.
...This paper presents a new twin-membrane calorimeter chip for fast differential scanning calorimetry (DSC) with the Flash DSC 1 of Mettler-Toledo. The thin silicon nitride membranes enable scan rates in excess of 10
kK/s in heating and up to 4
kK/s in cooling for sample masses between 100
ng and 10
μg in the temperature range of −100
°C to 450
°C. The time constant for cooling is about 12
ms, the power resolution is typically 0.1–0.5
μW, the temperature accuracy of non-calibrated chips is typically better than ±5
K. The paper also shows measurements for the scan-rate dependent thermal lag of the device, showing an empty sensor thermal lag of about 0.2
ms, and a mass dependent thermal lag of about 0.3
ms/μg for Indium for a good thermal contact between Indium and membrane.
Two very promising materials as the BrilLanCe (Cerium doped Lanthanum Bromide, LaBr3(Ce) and the LYSO (Lutetium Yttrium OxyorthoSilicate, Lu2(1−x) Y2x SiO5 (Ce)) coupled to Silicon photomultipliers ...(MPPC/SiPM) could represent an appealing option for the future calorimetry. The response of both LaBr3(Ce) and LYSO detectors having MPPC as photosensors have been studied via detailed Monte Carlo (MC) simulations. The impinging gammas are in the range of 50–100 MeV. The MC simulations are based on GEANT4, including the full electronic chain up to the waveform digitizer and finally the reconstruction algorithms.
The results have been obtained are very promising. For a detector based on a (radius R = 4.45 cm, length L = 20.3 cm) LaBr3(Ce) crystal an energy resolution of σE/E%=2.3(1) and a timing resolution of σtps = 35(1) have been predicted. The energy resolution can be further improved by using larger crystals (either R = 6.35 cm or R = 7.6 cm, L = 20.3 cm) approaching respectively a σE/E%=1.20(3) or a σE/E%=0.91(1). Detector based on LYSO crystal of similar size performs even better, thanks to the shorter LYSO Moliere radius compared to the LaBr3(Ce) one. For a detector based on a (R = 3.5 cm, L = 16 cm) LYSO crystal an energy resolution of σE/E%=1.7(1)% can be obtained, and that can be further improved using bigger crystals (R = 6.5 cm, L = 25 cm, σE/E%=0.74(1)%. Energy resolution approaching σE/E%=0.3(1)% can be addressed for both crystals with ultimate sizes (R = 20–23 cm, L = 17–32 cm), complemented by timing and position resolutions in the range of O(30) ps and O(a few mm) respectively. Such results put these future high energy calorimeters at the detector forefront at intensity frontiers.
