Calorimetric Method Research Articles

Methods for faster estimation of the entropy profile of a lithium-ion battery: A comparison of accelerated potentiometry and the estimation of entropy through thermal signatures

The operating temperature of a lithium-ion battery (LIB) has strong effects on its electrochemical performance, safety, and lifetime. Reliable predictions of cell temperature and heat generation rate are required for the design and thermal management of battery systems. The entropy variation of a LIB has a significant influence on the heat generation and the cell temperature variation, especially at a lower C-rate. Since the entropy is a function of State-of-Charge (SoC), and may change during ageing, the entropy profile may as well be used as an indicator for battery State-of-Health diagnostics. The present experimental methods, such as potentiometric or calorimetric methods, for determining the entropy variation throughout a battery's full SoC window are time-consuming and require specialized equipment with good thermal insulation and instrumentation. Hence, faster and more convenient methods are needed. In this paper, we compare an accelerated potentiometric method with a new entropy characterization method where the entropy profile is extracted from the thermal signature of a LIB during charge and discharge at low C-rates. The accelerated potentiometric method aims to obtain the entropy from thermal cycling while the cell is still not completely relaxed to its stable OCV. The thermal signature method monitors the variations of a cell's outer surface temperature during a low constant current charge or discharge, from which the continuous variation of entropy with SoC can be extracted. The obtained entropy profile was validated through a modeling approach that combines a P2D-electrochemical model for battery operation and a 3D-finite-element model for the thermal behavior during battery operation. Good agreement between the model predictions and experiments was achieved on the temporal variation of the cell's outer surface temperature.

Monitoring in-situ dissolution of polystyrene-acrylonitrile (SAN) via calorimetry and spectroscopy

Dissolution/precipitation recycling is an environmentally friendly solution that could be potentially implemented for ABS recycling. In this paper, a set of useful calorimetric, spectroscopic, and rheological techniques and methods are presented to monitor in-situ the dissolution of the ABS matrix: poly(styrene-acrylonitrile) (SAN). In line with the Hansen solubility parameters, methyl ethyl ketone (MEK) has been selected to be a suitable solvent for SAN dissolution. Thermodynamic and kinetic aspects of the dissolution process were investigated by using calorimetry and in-situ ATR-FTIR spectroscopy. Through an isoconversional method, the effective activation energy and the main steps involved in the dissolution process were determined. A rheological characterization of the solution SAN-MEK was also performed to provide further information on the rheological behavior.

A hybrid experimental configuration for emissivity measurement at cryogenic temperatures

Abstract In cryogenic and high vacuum systems, radiation mode of heat transfer is the primary source of energy interaction owing to the wide temperature differentials and very low temperatures and pressures. Measurement of radiative properties such as emissivity is crucial in the design of cryogenic systems. Emissivity measurement at cryogenic temperatures requires careful consideration of the sample preparation and measurement conditions to ensure accuracy and reliability. Most experimental techniques developed so far are complex in their design and equipment, and they work only on a single measuring method. To address these challenges, this research has proposed a simpler and hybrid experimental setup that could employ both calorimetric and heat flux methods to directly measure the total hemispherical emissivity in the range 90 K–180 K. Experiments were conducted with five types of materials (black paint, stainless steel, aluminum foil, aluminized mylar foil, and copper sheet) by using both methods, and the results were validated with the literature data. The data obtained by calorimetric and heat flux methods for each sample showed a high level of consistency with each other, with a variation of only ±1.5%. Moreover, the discrepancy between the measured and literature data was within the acceptable range of 0.3%–10%. The total hemispherical emissivity of mechanically treated copper was higher than that of chemically polished copper by 11%. This simplified setup has incorporated all possible means to minimize heat leakages into and from the cryostat while maintaining accuracy. The obtained data can be used to accurately estimate the radiation heat loads in cryopumps and other cryogenic systems that use similar components.

Dependence of the decomposition rate of furoxanes on the polarity of the solvent

The decomposition rates of diphenylfuroxane and a number of 4-nitro-3-alkyl-furoxanes in dilute solutions were measured by manometric and calorimetric methods. In no case, an increase in the reaction rate was detected with an increase in the polarity of the solvent, which corresponds to the absence of an increase in the dipole moment of the molecule during the formation of a transition state. Based on this result, a conclusion is made about the biradical mechanism of decomposition of uncondensed disubstituted furoxanes in solutions.

Characterization of thermal decomposition behavior of nitroaniline compounds with diverse functional groups by multiple calorimetric methods

Characterization of thermal decomposition behavior of nitroaniline compounds with diverse functional groups by multiple calorimetric methods

Comparative Calorimetric Method for Magnetic Component Losses Measurement With High Frequency

Comparative Calorimetric Method for Magnetic Component Losses Measurement With High Frequency

Mild to Moderate Normalization of Lipid Profile, Blood Pressure and Body Weight of Obese and Hyperlipidemic Patients by Herbs and Allopathic Agents

The research study was planned to observe effects of Nicotinic acid (niacin) and psyllium husk on blood pressure, body weight, LDL-cholesterol and HDL-cholesterol. It was single blind placebo controlled research study, which was conducted at Lahore Journal Hospital, from April 2023 to December 2023. Forty male and female hyperlipidemic patients were included in the research study, among which 20 patients were on placebo as control group, and 20 were on tablet Niacin, 2.25 grams daily, in divided doses for the period of three months. Patients with diabetes mellitus, peptic ulcer, renal disease, hepatic disease, hypothyroidism and alcoholism were excluded from the study. Body weight and blood pressure of patients were recorded at fortnightly visit. LDL-Cholesterol was calculated by Friedwald formula (LDL= TC- (TG/5 + HDL-C). Serum HDL-cholesterol was determined by direct method. Serum cholesterol and triglycerides were estimated by the enzymatic calorimetric method. Data regarding results were expressed as the mean ± SD and “t” test was applied to determine statistical significance of results. A probability value of <0.05 was the limit of significance. Three patients were dropped from the study due to side effects of Niacin. In three months of treatment with 2.25 grams of niacin HDL-cholesterol increased from 36.41±1.96 to 43.70±1.81 mg/dl, which was highly significant change when analyzed statistically. Niacin has decreased LDL-Cholesterol from 182.58±8.74 mg/dl to 119.29±4.08 mg/dl, which was highly significant (P<0.001), when compared statistically by paired “t” test. Overall percentage (%) changes from day-0 to day-90 were 34.66. Triglycerides reduced from 169.64±7.60 to 137.35±6.31 mg/dl, which was highly significant (P value <0.001) reduction in three months. Niacin has also reduced Blood Pressure. Difference between mean values of systolic and diastolic blood pressure at day-0 and day-90 were found highly significant (P<0.001). Body weight was reduced from 66.29±194 kg to 64.79±1.82 kg in three months. This change was significant (P<0.01). We concluded from the research study that niacin decreases blood pressure, body weight and LDL-Cholesterol and increases HDL-cholesterol in primary hyperlipidemic patients. KEY WORDS: Blood pressure, diabetes, body weight, hyperlipidemia, herbs, allopathy.

Thermoporometry measurements of human hair via differential scanning calorimetry.

Hair fibres possess an inherently porous structure, which is affected by physical and chemical agents from the environment, as well as those from cosmetic treatments. The present work aims to investigate the potential of a calorimetric method for evaluating the changes of hair porosity, in terms of pore size and size distribution. The temperature of the phase transition from solid to liquid is known to be depressed if the liquid is confined within a pore. This shift in temperature can be measured by a calorimetric method like differential scanning calorimetry, DSC. This method is termed thermoporometry and it is the tool used for investigating hair porosity in this work. Virgin and bleached hair fibres are measured by DSC and, by using the equations developed for water behaviour confined in pores of a solid, the size and size distribution of the hair pores are evaluated, and the influence of the cosmetic treatment on the pores is discussed. Thermoporometry measurements of hair produced results in good agreement with those obtained by other methods for measuring hair porosity. The analysis of the data suggests that the fibre pores are mostly of a radius of 4 nm, and that the bleaching process increases the total volume of pores through the addition of smaller pores. A prolonged bleaching process appears to reduce the amount of fine pores produced by the first short process, resulting in fewer, but larger, cavities, most likely through a process of pore-merging.

A multifunctional DNA tetrahedron for imaging, gene therapy, and chemotherapy-phototherapy combination: Binding affinity and anticancer activity

Imaging, silencing cancer-related microRNA, and chemotherapy-phototherapy (CTPT) combination therapy are crucial for cancer diagnosis and drug resistance overcoming. In this study, we designed a multifunctional DNA tetrahedron (MB-MUC1-TD) for the targeted delivery of combined daunorubicin (DAU) + toluidine blue O (TBO). The detection limit of miRNA-21 was determined to be 0.91 nM. The intercalation of DAU and TBO into MB-MUC1-TD was proved by spectroscopic and calorimetric methods. The thermodynamic parameters for the interactions of DAU and/or TBO with MB-MUC1-TD confirmed high drug loading. The first addition of TBO in the ternary system achieved a higher loading of both drugs and a more stable complex structure. Deoxyribonuclease I (DNase I) accelerated the release of DAU and/or TBO loaded in MB-MUC1-TD. Confocal laser scanning microscope demonstrated that MB-MUC1-TD exhibited good imaging ability for miRNA-21 to accurately identify cancer cells, and DAU/TBO was predominantly distributed within the nucleus of cancer cells. In vitro cytotoxicity showed better gene therapy efficacy of MB on MCF-7 cells, better biocompatibility of loaded DAU and TBO on LO2 cells, and stronger synergistic cytotoxicity of DAU + TBO on MCF-7/ADR cells. This study may establish a theoretical foundation for co-loading CTPT combination drugs based on multifunctional DNA nanostructures.

Thermodynamic Study of 1,4-Bis(3-methylimidazolium-1-yl)butane Bis(trifluoromethylsulfonyl)imide ([C4(MIm)2][NTf2]2) from 6 to 350 K.

The molar heat capacity of 1,4-bis(3-methylimidazolium-1-yl)butane bis(trifluoromethylsulfonyl)imide dicationic ionic compound ([C4(MIm)2][NTf2]2) has been studied over the temperature range from 6 to 350 K by adiabatic calorimetry. In the above temperature interval, this compound has been found to form crystal, liquid, and supercooled liquid. For [C4(MIm)2][NTf2]2, the temperature of fusion T°fus = (337.88 ± 0.01) K has been determined by the fractional melting experiments, the enthalpy of fusion ΔfusH° = (52.79 ± 0.28) kJ mol-1 has been measured using the calorimetric method of continuous energy input, and the entropy of fusion ΔfusS° = (156.2 ± 1.7) J K-1 mol-1 has also been evaluated. The standard thermodynamic functions of the studied dicationic ionic compound, namely, the heat capacity Cp°(T), the enthalpy [H°(T) - H°(0)], the entropy S°(T) and the Gibbs free energy [G°(T) - H°(0)] have been calculated on the basis of the experimental data for the temperature range up to 350 K. The results have been discussed and compared with those available in the literature and in the NIST Ionic Liquids Database (ILThermo) for monocationic ionic compounds.

International inter-laboratory comparison of solar heat gain coefficient of building-integrated photovoltaic modules results of tests with or without power generation and tests with PV cell coverage ratios

The solar heat gain coefficient is one of the important indicators to evaluate the performance of the building envelope components. In a BIPV module, secondary heat transfer to the indoors is reduced, compared to conventional glazing, due to the shielding effect of the PV cells and energy conversion by power generation. There is a difference in SHGC between power-generating (MPP) and effectively open-circuit (OC) states. In this paper, in order to prepare a calorimetric SHGC evaluation methodology for BIPV modules, we documented the current status of the experimental calorimetric test methods and test apparatus adopted by test laboratories in four different countries and identified the differences. Differences between the test laboratories were found in to the applied test methods, solar simulator types, spectral distributions, DC or AC power supplies for the solar simulator, irradiation inhomogeneity on the light-receiving surface of the test sample, temperature conditions between the test chamber and the metering box, and surface heat transfer coefficients. Especially, the round-robin test results obtained in an interlaboratory comparison clarified that the differences in the characteristics of the Calorimetic Hot Box and the Heat Flux Metering methodologies with a cooled plate, the differences in irradiation inhomogeneity on the light-receiving surface of the test sample and differences in surface heat transfer coefficients significantly affect the SHGC evaluation for BIPV modules. In addition, for the SHGC test in the MPP state, it was confirmed that an absolute SHGC reduction effect of 0.02 to 0.04 was obtained for a PV laminate with 81 % cell coverage, for all SHGC test methods and test apparatus. Pe characterises the effect of converting part of the sunlight absorbed by the PV cell into electric power and extracting it from the BIPV module, reducing the heat re-radiated indoors compared to the OC state. Due to this mechanism, the reduction effect Pe always occurs during power generation, regardless of the type of PV cell technology and whether the PV cells are opaque or transparent. In addition, the decrease in SHGC for a given glazing configuration was found to be proportional to the increase in PV cell coverage ratio. SHGC tests with four different cell coverage ratios confirmed that the relationship between PV cell coverage ratio and SHGC is linear to a high degree of accuracy when no electric power is extracted (OC state), provided that the incident radiation is spatially homogeneous. The results obtained will be useful when proposing a calorimetric SHGC evaluation methodology for international standardization, as they document the differences due to a range of test facilities and testing conditions, differences caused by power generation and extraction, and the effect of varying PV cell coverage ratios. The insights gained were valuable in identifying which aspects of test methodology and boundary conditions must be specified with particular attention to detail when calorimetric testing standards are extended to explicitly address the SHGC determination of BIPV modules.

Pore structures and deterioration mechanism of concrete after cryogenic freeze-thaw cycles: Effects of moisture contents and aggregates

With the popularization of all-concrete liquefied natural gas (ACLNG) storage tanks, the performance of concrete after cryogenic exposure (−170 °C) has garnered significant interests from researchers. To investigate the damage mechanism of pore structures and the corresponding influencing factors, this study involved subjecting concrete with two moisture contents, namely air-dried and water-saturated to 10 cryogenic freeze-thaw cycles (CFTCs) to assess the variation laws in strengths. The mercury intrusion porosimetry (MIP), nitrogen adsorption and desorption (NAD), scanning electron microscopy (SEM), backscattered scanning electron (BSE) and low-temperature calorimeter (LTC) methods were employed to evaluate pore characteristics and the phase transition of pore water. Furthermore, pore structures were conducted using fractal dimensions based on the Zhang model and Frenkel-Halsey-Hill model. Findings indicate that there is a more pronounced reduction in strengths after 10 CFTCs in water-saturated state. Following cryogenic exposure, the porosity of paste increases from 4.97 % to 5.58 % and 7.04 %, and the porosity of mortar rises from 6.05 % to 7.20 % and 8.76 %, respectively. Aggregates in mortar contribute to more severe damage to pore structures in cryogenic circumstances, particularly capillary and macropores. The nucleation of pore water and ice contents are greatly influenced by moisture contents, and the frozen fraction is only 84.3 % in air-dried state. The destruction of gel pores is attributed to the continuous multi-order phase transition in water-saturated state. This work conducts a thorough cross-scale analysis of the pore structure in both paste and mortar, and it quantitatively evaluates the phase transition of pore water under cryogenic conditions using the LTC method. Ultimately, the influence of moisture contents and aggregates on the pore structures are evaluated, which provides deeper insights into the deterioration mechanism of concrete following cryogenic exposure.

Multitechnique approaches for characterising phase behaviour in food biopolymer systems

SummaryUnderstanding the phase behaviour of biopolymer composites is vital for various technological applications, such as developing functional foods, nutraceuticals, encapsulation, isolation and fractionation of enzymes and proteins. The growing consumer demand for healthier food products pressures the food and nutraceutical industries to innovate while maintaining traditional texture and nutritional quality. This review critically examines various analytical techniques, including spectroscopic, microscopic, calorimetric, rheological, viscometry, and diffraction methods, used to study phase behaviour. Each technique provides unique insights into phase behaviour mechanisms at micro and macroscopic levels, with respective advantages and limitations discussed. The review advocates for a multi‐technique approach for a comprehensive understanding of phase behaviour and highlights the development of in situ probing techniques with minimal sample pre‐processing as a promising advancement. These innovations are expected to significantly enhance the practical applications of these techniques in the food industry, meeting current consumer demands without compromising traditional qualities.

Studies on in vivo antithrombotic activity of quercetin, a natural flavonoid isolated from a traditional medicinal plant, African eggplant (Solanum indicum)

Ethnopharmacological relevanceEvery year, cardiovascular diseases (CVDs) account for about 17.9 million deaths, making them the primary cause of both morbidity and mortality. Conventional drugs, which are often prescribed to treat cardiovascular diseases, are costly and have adverse effects. Consequently, dietary modifications and other medications are needed. Traditional use of Solanum indicum as cardiotonic to treat hypertension and anticoagulant potency has been reported but poorly evaluated scientifically. Aim of the studyThis study investigated the in vivo anticoagulant activity and mechanism of anticoagulation of quercetin (QC), a bioactive compound isolated from S. indicum (SI) hydroethanolic fruit extract. Materials and methodsBioassay-guided fractionation (anticoagulant activity) extracted QC from hydroethanolic SI extract. QC was extensively characterized biochemically and pharmacologically. The interaction between QC and thrombin was investigated using spectrofluorometric and isothermal calorimetric methods. Cytotoxicity, antiplatelet, and thrombolytic studies were carried out in vitro. The Swiss albino mice were used to assess the in vivo, anticoagulant, and antithrombotic activities of QC. ResultsQC exhibits anticoagulant activity via (i) uncompetitive inhibition of thrombin but not FXa with a Ki value of 33.11 ± 4.2 μM and (ii) a partial inhibition of thrombin-catalyzed platelet aggregation with an IC50 value of 13.2 ± 1.2 μM. The experimental validation of the in silico study's prediction of QC's binding to thrombin was confirmed by spectrofluorometric and isothermal calorimetric analyses. QC was nontoxic to mammalian, non-hemolytic cells and demonstrated thrombolytic activity by activating plasminogen. QC demonstrated in vivo anticoagulant efficacy, preventing k-carrageen-induced thrombus formation in mice's tails. In the acute circulatory stasis paradigm in mice, QC reduces thromboxane B2 (TXB2) and endothelin-1 (ET-1) while increasing nitric oxide synthase (eNOS) and 6-keto prostaglandin F1α (6-keto-PGF1 α). ConclusionEffective in vivo anticoagulant and antithrombotic properties of S. indicum's bioactive component QC point to the plant's potential use as a herbal anticoagulant medication for preventing and treating cardiovascular diseases linked to thrombosis.

Estimation of neutral beam injector power transferred to KSTAR plasmas

KSTAR shows the long pulse capability based on superconducting magnet and NBI plays a crucial role in sustaining the plasma via plasma heating and current driving. So, the accurate NBI power measurement transferred to KSTAR plasma is important for the analysis of plasma transport as well as plasma performance parameters. In a long pulse operation, the water coolant temperature is at the steady state condition in longer pulse more than 20s and the coupled neutral beam power to KSTAR plasma during the tokamak experiments is rechecked by using water flow calorimetric method after the experiment. The effect of beam duct scraper loss which was not considered at the neutral beam power calibration process is less than 5 % in terms of neutral beam power. However, in long pulse operation of NBI in KSTAR experiments, high strength of stray PF affects the beam path, the neutral beam power registered on mds + using beam current method is over estimated and it is calculated up to a few percent in terms of neutral beam power using calorimetric method. Therefore, it is necessary to consider the beam power variation by PF effect to interpret the plasma performance degradation in long pulse operation. Lastly. when the ion source tun on or turn off in condition other ion sources are operated, the beam transmission power is also affected because of sharing the beam box for ion sources so that the careful power estimation is necessary for such kind of beam power modulation experiments in KSTAR.

Weak association between urea-creatinine ratio and c-reactive protein with nutritional risk in hospitalized patients with COVID-19: A cross-sectional study

BackgroundCOVID-19 is a systemic infection with a significant impact on nutrition risk and the hematopoietic system. The neutrophil-lymphocyte ratio (NLR) may have prognostic value in determining severe cases of COVID-19 and the urea-creatinine ratio (UCR) is currently being studied as a potential biomarker of catabolism associated with critical illness. The aim was to assess the association between the NLR, UCR and C-reactive protein (CRP) with nutritional risk in hospitalized patients with COVID-19. MethodsThis is a retrospective cross-sectional study that assessed 589 hospitalized patients with COVID-19, 18 years of age or older, of both sexes. Nutritional risk was assessed by Nutritional Risk Screening (NRS, 2002) and NLR by neutrophils divided by lymphocyte count. The UCR was calculated by the ratio between urea and creatinine and quantified by the calorimetric biochemical method and CRP by the immunoturbidimetric method. Differences between groups were applied by the Mann-Whitney U test and the automated binary regression test. ResultsOf the 589 patients, 87.4% were at nutritional risk. When evaluating patients admitted to the ICU, 91.9% were at nutritional risk. Patients with NRS ≥3 are older, with lower body mass and BMI, higher NLR and UCR and lower CRP values. However, 73% of patients admitted to the ward were at nutritional risk, and only age differed between groups, being higher in patients with NRS ≥3. Logistic regression showed a weak association between nutritional risk in NRS and UCR (Model 1) (OR=0.96, p=0.003) and NRS with CRP (Model 1) (OR=1.01, p<0.001) in patients in the ICU. On the other hand, the logistic regression in ward patients found association only for CRP in both models (Model 1, OR=1.01, p=0.041) and (Model 2, OR=1.01, p=0.031). ConclusionWe found a low association between nutritional risk and UCR and CRP in patients admitted to the ICU, while in the ward patients the nutritional risk also had weak association with CRP.

Probabilistic Printability Maps for Laser Powder Bed Fusion Via Functional Calibration and Uncertainty Propagation

Abstract In this work, we develop an efficient computational framework for process space exploration in laser powder bed fusion (LPBF) based additive manufacturing technology. This framework aims to find suitable processing conditions by characterizing the probability of encountering common build defects. We employ a Bayesian approach toward inferring a functional relationship between LPBF processing conditions and the unobserved parameters of laser energy absorption and powder bed porosity. The relationship between processing conditions and inferred laser energy absorption is found to have good correspondence to the literature measurements of powder bed energy absorption using calorimetric methods. The Bayesian approach naturally enables uncertainty quantification and we demonstrate its utility by performing efficient forward propagation of uncertainties through the modified Eagar–Tsai model to obtain estimates of melt pool geometries, which we validate using out-of-sample experimental data from the literature. These melt pool predictions are then used to compute the probability of occurrence of keyhole and lack-of-fusion based defects using geometry-based criteria. This information is summarized in a probabilistic printability map. We find that the probabilistic printability map can describe the keyhole and lack-of-fusion behavior in experimental data used for calibration, and is capable of generalizing to wider regions of processing space. This analysis is conducted for SS316L, IN718, IN625, and Ti6Al4V using melt pool measurement data retrieved from the literature.

A Comparative Study of Fire Code Classifications of Building Materials

Whether noncombustible or combustible construction is used, the presence of combustible materials is likely to be used for various reasons, such as interior finishes, flooring, and insulation. Consequently, how regulations consider the degree of combustibility in their fire classifications will influence the level of fire safety provided in these buildings and the exchanges between all actors in the construction sector. In North America, the regulation of combustibility is primarily governed by surface flame spread assessed through the Steiner tunnel test. While there is a growing prevalence of calorimetric methods globally, their incorporation into North American building codes remains notably limited. Based on ISO 5660-1 cone calorimeter test results of twenty commercially available North American building materials, a comparative study was conducted between the Canadian flame spread classification and the classifications in Japan, New Zealand and the European Union (Euroclass). The tests and their limitations are described herein, as well as the conceptual frameworks. The results suggest that as materials’ combustibility levels increase, the level of agreement between classifications decreases and remains binary. The choice between the material and system scales is crucial for determining the effective development and implementation of regulations.

Investigating the Effects of the Physicochemical Properties of Cellulose-Derived Biocarbon on Direct Carbon Solid Oxide Fuel Cell Performance.

This paper presents a study of the characteristic effects of the physicochemical properties of microcrystalline cellulose and a series of biocarbon samples produced from this raw material through thermal conversion at temperatures ranging from 200 °C to 850 °C. Structural studies revealed that the biocarbon samples produced from cellulose had a relatively low degree of graphitization of the carbon and an isometric shape of the carbon particles. Based on thermal investigations using the differential thermal analysis/differential scanning calorimeter method, obtaining fully formed biocarbon samples from cellulose feedstock was possible at about 400 °C. The highest direct carbon solid oxide fuel cell (DC-SOFC) performance was found for biochar samples obtained via thermal treatment at 400-600 °C. The pyrolytic gases from cellulose decomposition had a considerable impact on the achieved current density and power density of the DC-SOFCs supplied by pure cellulose samples or biochars derived from cellulose feedstock at a lower temperature range of 200-400 °C. For the DC-SOFCs supplied by biochars synthesised at higher temperatures of 600-850 °C, the "shuttle delivery mechanism" had a substantial effect. The impact of the carbon oxide concentration in the anode or carbon bed was important for the performance of the DC-SOFCs. Carbon oxide oxidised at the anode to form carbon dioxide, which interacted with the carbon bed to form more carbon oxide. The application of biochar obtained from cellulose alone without an additional catalyst led to moderate electrochemical power output from the DC-SOFCs. The results show that catalysts for the reverse Boudouard reactions occurring in a biocarbon bed are critical to ensuring high performance and stable operation under electrical load, which is crucial for DC-SOFC development.

Thermal and Combustion Properties of Biomass-Based Flame-Retardant Polyurethane Foams Containing P and N.

Biomass has been widely used due to its environmental friendliness, sustainability, and low toxicity. In this study, aminophosphorylated cellulose (PNC), a biomass flame retardant containing phosphorus and nitrogen, was synthesized by esterification from cellulose and introduced into polyurethane to prepare flame-retardant rigid polyurethane foam. The combustion properties of the PU and PU/PNC composites were studied using the limiting oxygen index (LOI), UL-94, and cone calorimeter (CCT) methods. The thermal degradation behavior of the PU and PU/PNC composites was analyzed by thermogravimetric analysis (TGA) and thermogravimetric infrared spectroscopy (TG-IR). The char layer after combustion was characterized using SEM, Raman, and XPS. The experimental results showed that the introduction of PNC significantly improved the flame-retardant effect and safety of PU/PNC composites. Adding 15 wt% PNC to PU resulted in a vertical burning grade of V-0 and a limiting oxygen index of 23.5%. Compared to the pure sample, the residual char content of PU/PNC15 in a nitrogen atmosphere increased by 181%, and the total heat release (THR) decreased by 56.3%. A Raman analysis of the char layer after CCT combustion revealed that the ID/IG ratio of PU/PNC15 decreased from 4.11 to 3.61, indicating that the flame retardant could increase the stability of the char layer. The TG-IR results showed that PNC diluted the concentration of O2 and combustible gases by releasing inert gases such as CO2. These findings suggest that the developed PU/PNC composites have significant potential for real-world applications, particularly in industries requiring enhanced fire safety, such as construction, transportation, and electronics. The use of PNC provides an eco-friendly alternative to traditional flame retardants. This research paves the way for the development of safer, more sustainable, and environmentally friendly fire-resistant materials for a wide range of applications.