Calorimetry Research Articles

Fluorocarbon-Capped Aluminum Nanoparticles: Synthesis, Characterization, Combustion, and Comparison to Hydrocarbon-Capped Aluminum Nanoparticles

ABSTRACT Aluminum nanoparticles (NPs) are attractive as fuel additives in propulsion or pyrotechnic applications, but their combustion is inhibited by native oxide layer formation, which also reduces the energy content. Capping Al NPs with fluorocarbon ligands may inhibit native oxide formation and create an intimate mixture of fuel with an oxidizer capable of reacting exothermically with both Al and the passivating oxide layer. We present an approach to producing Al NPs capped by perfluorotetradecanoic acid (PFTDA), based on rapid mechanical attrition of NPs followed by PFTDA capping under mild conditions. The materials were characterized by dynamic light scattering, electron microscopy with energy dispersive spectroscopy, elemental analysis, X-ray photoelectron spectroscopy, X-ray diffraction, and infrared spectroscopy. Ignition and combustion properties were studied using bomb calorimetry, thermogravimetric analysis with differential scanning calorimetry, and photographic analysis of both flame and laser ignition of particle samples. For comparison, Al NPs were produced identically but capped with a hydrocarbon (oleic acid). PFTDA-capped NPs were found to ignite at lower laser power and burn far more vigorously than oleic acid-capped NPs, despite the observation that oleic acid capping resulted in a thinner native oxide layer on the air-exposed NPs. PFTDA-capped NPs were also found to have shorter ignition delay and lower ignition energy compared to commercially available Al NPs. XPS and XRD were used to probe the combustion products for the PFTDA-capped NPs, confirming formation of AlF3 and other products. Density functional theory was used to calculate the heat of formation of PFTDA, which was then used to calculate reaction enthalpies for reactions in both inert and oxidizing environments.

Bait Biomass and Caloric Contribution From the Dungeness Crab (Cancer magister) Fishery in Oregon, USA

ABSTRACTFishery discards worldwide increase the availability of organic materials on the benthos, altering trophic relationships and potentially increasing the abundance of benthic consumers. Expert knowledge from fishers is a valuable yet often underutilized source of information to understand these dynamics. We interviewed Dungeness crab fishers (n = 24) to determine the most‐used bait types and to characterize regional and seasonal bait use strategies that drive inputs of organic matter into Oregon coastal waters during the commercial Dungeness crab fishery each year. Based on bomb calorimetry measurements of caloric densities of 12 commonly reported bait species, total energetic input was 12.99 × 109 kJ (3.10 B kcal) from bait in the 2019–2020 commercial ocean Dungeness season in Oregon, USA. Fishing effort and bait inputs were strongly seasonal, with 88% of effort concentrated in the first 60 days of the 9‐month‐long season but did not vary regionally. This large, temporally concentrated caloric input suggested that bait could contribute substantially to Dungeness crab productivity. Fisher respondents indicated that bait effectiveness was the most important motivating factor in choosing a bait type, more than availability or cost.

The Volatility of Energetic Materials and How to Safely Determine Them: Exemplified by Nitro-Pyrazoles via Transpiration Method, Differential Scanning, and Bomb Calorimetry

The Volatility of Energetic Materials and How to Safely Determine Them: Exemplified by Nitro-Pyrazoles via Transpiration Method, Differential Scanning, and Bomb Calorimetry

Study of improving the quality of charcoal briquettes mixed to sago barks and sago dregs as an alternative energy source

Abstract The sago processing industry generates waste in the form of sago barks and dregs, which often polluting the environment, To address this issue, one promising solution is the conversion of these waste into renewable energy such as briquettes. This study aims to improve the quality of sago dreg briquettes by incorporating sago barks, aiming for compliance with charcoal briquette standards and indoor air quality regulations concerning to briquette combustion emissions. Various mixing ratios were examined, to determine the optimal composition. The manufacturing process followed the standard guidelines outlined in SNI 01-6235-2000. Testing procedures encompassed proximate analysis, calorific value determination via bomb calorimetry, and assessment of CO gas emissions using an Environmental Combustion Analysis (ECA) tool. Results indicated a significant influence of the Barks-dreg ratio on physical characteristics, combustion behavior, and CO emissions. The KBA2 mixture, comprising 90% barks and 10% dregs, exhibited the most good attributes, including moisture (2%), ash (10.32%), fly matter (20.66%), bound carbon content (69.02%), and calorific value (5806.4 cal/g). Emission testing with the ECA tool confirmed CO emissions of 357 mg/Nm3, well within acceptable limits. In conclusion, this study shows that mixing sago barks and sago dregs in certain proportions can produces briquettes that meet quality standars, which have the potential for sustainable energy production in the sago industry.

Intestinal Energy Harvest Mediates Gut Microbiota-Associated Weight Loss Following Bariatric Surgery.

Metabolic and bariatric surgery (MBS) is the most effective treatment for class III obesity. The capacity to efficiently extract intestinal energy is potentially a determinant of varying weight loss outcomes post-MBS. Prior research indicated that intestinal energy harvest is correlated with post-MBS weight loss. Studies have also demonstrated that the gut microbiota is associated with weight loss post-MBS. We aim to investigate whether gut microbiota-associated weight loss is mediated by intestinal energy harvest in patients post-MBS. We examined the relationship between specific gut microbiota, intestinal energy harvest, diet, and weight loss using fecal metagenomic sequence data, bomb calorimetry (fecal energy content as a proxy for calorie absorption), and a validated dietary questionnaire on 67 individuals before and after MBS. Mediation analysis and amachine learning algorithm were conducted. Intestinal energy harvest was a mediator in the relationship between theintestinal microbiota (Bacteroides caccae) and weight loss outcomes in patients post-MBS at 18months (M). The association between the abundance of B. caccae and post-MBS weight loss rate at 18M was partly mediated by 1M intestinal energy harvest (β = 0.001 ± 0.001, P = 0.020). This mediation represents 2.83% of the total effect (β = 0.050 ± 0.047; P = 0.028). Intestinal microbiota and energy harvest improved random forest model's accuracy in predicting weight loss results. Energy harvest partly mediates the relationship between the intestinal microbiota and weight loss outcomes among patients post-MBS. This study elucidates a potential mechanism regarding how intestinal energy absorption facilitates the effect of intestinal microbiota on energy metabolism and weight loss outcomes.

Energy release effect of micro-nano self-assembled aluminum powders and application in composite explosives

Nano aluminum powder effectively enhances reactivity, thereby improving energy-containing materials' performance. To investigate micro-nano self-assembled aluminum powders' energy output and their application in composite explosives, we tested the heat of combustion and ignition characteristics (ignition delay, ignition energy, flame propagation speed) using oxygen bomb calorimetry and Hartmann tube. Results showed that the combustion heat decreased with increasing nano aluminum powder content. The addition of nano aluminum powders substantially decreased ignition delay and energy, enhancing the combustion rate and reactivity of aluminum powder dust. The ranking of reactivity among the five aluminum powders was as follows: μ@n-Al-10 % > μ@n-Al-5% > μ/n-Al-10 % > μ/n-Al-5% > μAl. Assessing explosives containing various aluminum powders showed that the self-assembled 5 % content sample had the highest heat of detonation at 8490 kJ/kg. Mechanical sensitivity increased with higher nano aluminum powder content, with explosives containing 5 % nano content exhibiting the highest safety performance.

Mechanical and thermal properties of composite carbonized briquettes developed from cassava (Manihot esculenta) rhizomes and groundnut (Arachis hypogea. L.) stalks with jackfruit (Artocarpus heterophyllus) waste as binder

Composite briquettes from agricultural residues are a potential sustainable domestic solid fuel resource. This study aimed to develop and characterize composite briquettes developed from cassava rhizomes and groundnut stalks with jackfruit waste binder as an alternative sustainable fuel for domestic cooking applications. Cassava rhizomes and groundnuts stalks feedstock were carbonized in a step-down kiln under slow pyrolysis conditions at temperatures between 400 and 500 ℃. Thermogravimetric analysis was used to determine the proximate and thermal properties of the developed composite briquettes. Bomb calorimetry was used to determine their heating values. Relaxed density, drop strength and compressive strength results were used to determine the mechanical properties of the developed briquettes. Design of Experiments (Box Behnken design) was used to evaluate the effect of factors (biochar amount, jackfruit waste binder amount, and amount of water) on the mechanical and thermal properties of the developed composite briquettes. The Coats-Redfern kinetic model was used to determine the activation energy for the developed briquettes. Calorific values and drop strength of developed composite briquettes ranged from 18.1 to 24.0 MJ/kg and 92–99%, respectively. Combustion performance results indicated that ignition temperature increased from 155.1 to 184 ∘C\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^\\circ{\\rm C}$$\\end{document}, when heating rate was increased from 10 to 15 ∘C\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^\\circ{\\rm C}$$\\end{document}/min. However, burnout temperature decreased from 618.1 to 453 ∘C\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^\\circ{\\rm C}$$\\end{document}/min with a similar corresponding increase in heating rate. Optimum biochar amount, amount of water, and jackfruit waste binder amount for optimal mechanical and thermal properties were 89.3%, 893.0 ml, and 29.5 g, respectively. Composite briquettes developed from cassava rhizomes and groundnut stalks with jackfruit waste as binder are suitable potential domestic cooking fuels.

Characteristics of composite briquettes produced from carbonized banana peels and waste glass

Briquettes made from carbonized agricultural residues present sustainable material alternatives to wood charcoal and firewood for commercial and industrial applications. However, these briquettes are plagued by property weaknesses including low drop strength and thermal efficiency. Therefore, this study focuses on enhancing the physical, mechanical and thermal properties of composite briquettes produced from carbonized banana peels and waste glass. Composite briquettes comprised of banana peels biochar and waste glass powder (0%, 5%, 10%, 20%, 30%, 40%, and 50%) were developed, characterized, and evaluated using thermo-gravimetric analysis and bomb calorimetry to determine thermo-physical properties and higher heating values, respectively. The thermal efficiency and emissions (CO, CO2, and PM2.5) were assessed using the water boiling test and an emissions monitoring system. Proximate analysis revealed that moisture content, volatile matter, fixed carbon, and ash content of the developed briquettes ranged from 2.5 to 9.7%, 19.2 to 37.2%, 28.7 to 55.6%, and 7.2 to 44.9%, respectively. Drop strength for the briquettes was 84% without waste glass in the composite, increasing to 94–98% with waste glass included in the composite matrix. Higher heating values ranged from 20.1 to 35.8 MJ/kg. Thermal efficiency rose from 22% with no waste glass powder to 40% with 50% waste glass powder addition, while CO and CO2 emissions decreased from 41 to 11 ppm; and 50 to 15 ppm, respectively. PM2.5 remained constant across all banana peel biochar waste glass composites. Notably, even a modest 10% waste glass composition significantly improved drop strength and thermal efficiency, but higher waste glass percentages correlated with elevated ash values and reduced higher heating values. Therefore, the developed composite briquettes can be used in commercial and industrial applications including in some industrial boilers.

Intestinal microbial and metabolite profile in infants with small bowel stomas after bowel resection.

Infants with small bowel stomas (SBstoma) frequently struggle with absorption and rely on parenteral nutrition (PN). Intestinal absorption is difficult to predict based solely on intestinal anatomy. The purpose of this study was to characterize the microbiota and metabolic by-products within stoma effluent and correlate with clinical features and intestinal absorption. Prospective cohort study collecting stoma samples from neonates with SBstoma (N = 23) or colostomy control (N = 6) at initial enteral feed (first sample) and before stoma closure (last sample). Gut bacteriome (16S ribosomal RNA [rRNA] sequencing), short-chain fatty acids (SCFAs) and bile acids (BAs) were characterized along with volume and energy content of a 48 h collection via bomb calorimetry (last sample). Hierarchical clustering and linear regression were used to compare the bacteriome and BAs/SCFAs, to bowel length, PN, and growth. Infants with ≤50% small bowel lost more fluid on average than those with >50% and controls (22, 18, 16 mL/kg/day, p = 0.013), but had similar energy losses (7, 10, 9 kcal/kg/day, p = 0.147). Infants growing poorly had enrichment of Proteobacteria compared to infants growing well (90% vs. 15%, p = 0.004). An increase in the ratio of secondary BAs within the small bowel over time, correlated with poor prognostic factors (≤50% small bowel, >50% of calories from PN, and poor growth). Infants with SBstoma and poor growth have a unique bacteriome community and those with poor enteral tolerance have metabolic differences compared to infants with improved absorption.

Anchovy and sardine condition and energy content in the North Aegean Sea (eastern Mediterranean) in relation to their contrasting reproductive strategies.

Forage species with high biomass, such as anchovies and sardines, play a key role in pelagic ecosystems and make up a significant proportion of the world's capture fisheries production. In recent years, condition indices have gained interest as significant indicators for assessing the effects of environmental and human pressures on these species and the quality of their habitats. In the present study, we examined, for the first time in the North Aegean Sea (eastern Mediterranean), the year-round variation in somatic and gonadal condition, energy density, and percentage of lipid content of anchovy (Engraulis encrasicolus) and sardine (Sardina pilchardus). Energy density was measured with bomb calorimetry and percentage lipid content with the fatmeter, a portable electronic device. Finally, the monthly changes in gonadal and energetic condition were examined in relation to the annual cycle of temperature and mesozooplankton biomass, simulated by the implementation of a coupled hydrodynamic-biogeochemical model (POM-ERSEM). There was a strong relationship between fish energy density (kJ g-1) and percentage dry weight. Furthermore, the mean monthly energy density and fatmeter measurements were strongly correlated, especially in sardine. Overall, the monthly changes in energetic condition were indicative of the species' different strategies for energy acquisition and allocation to reproduction (capital vs. income breeding): sardine exhibited low energy density and percentage lipid content during the winter spawning period (November-March) and markedly higher energetic condition from spring to autumn (April-October). Anchovy spawning period, as inferred from gonadal condition, lasted from April to September, i.e., during the warm period of the year but its energy density and percentage lipid content did not exhibit any seasonal changes and were markedly lower than in sardine from April to October. Finally, the simulated mesozooplankton biomass was higher from January to July, which corresponded to the second half of the spawning season for sardine, but first half of the spawning season for anchovy.

The synthesis and properties of low sensitivity and heat resistant guanidine salts

This paper uses a simple method to synthesis four guanidine salts of nitrophenols and tetrazoles with low sensitivity (friction sensitivity and impact sensitivity) and high decomposition temperature. The crystal structures were tested by an X-ray single crystal diffractometer. Thermal decomposition behaviors were examined via differential scanning calorimetry (DSC), revealing decomposition temperatures of 295.04 °C, 332.57 °C, 252.51 °C, and 301.17 °C, all exceeding 250.00 °C. The detonation velocities and pressures were calculated using Explo5 based on the experimentally measured combustion heat. The detonation velocities for the four guanidine salts followed the order 4 (7667 m s−1)＞ 2 (6909 m s−1)＞ 3 (6722 m s−1)＞ 1 (6560 m s−1), and the explosion pressures were ranked as 4 (19.13 GPa)＞ 2 (17.72 GPa)＞ 1 (14.96 GPa)＞ 3 (12.43 GPa). The combustion heats were measured using oxygen bomb calorimetry and were found to be 2 (11.85 kJ g⁻1) > 3 (11.66 kJ g⁻1) > 4 (11.31 kJ g⁻1) > 1 (10.57 kJ g⁻1). The impact sensitivity was greater than 100 J, and the friction sensitivity was greater than 360 N. Given these advantages, it is anticipated that these compounds could have applications in propellants and gas generators.

Predicting calorific value and ash content of sand shrub using Vis-NIR spectra and various chemometrics

Calorific value (CV) reflects the ability of material flow and energy conversion of plants, which is the key indices of combustion properties for utilization and development of energy plants. However, the commonly used method for CV determination of solid fuels is bomb calorimetry in the laboratory using powder samples, which hinders the capability of rapid and non-destructive prediction for a large-scale samples in a natural environment. Visible and near infrared spectroscopy (Vis-NIR) has been widely proposed as a replace for laboratory determination in properties prediction. However, chemometrics are essential for spectral analysis. Various chemometrics including competitive adaptive reweighted sample (CARS), lifting wavelet transform (LWT), successive projections algorithm (SPA), and convolutional neural networks (CNNs) optimized by whale optimization algorithm (WOA) were employed to optimize models. Additionally, canopy spectra were measured in the field instead of powder samples’ spectra collecting from laboratory. The results demonstrated that CARS-WOA-CNN was the best to predict CV and ash content (AC) with R2 of 0.858 and 0.751, respectively. Compared to raw full spectra, spectral dimension was reduced from 2048 to 93 and 22 for CV and AC, respectively. Overall, this study provided a meaningful strategy for harvest planning and assessing value of biomass in the field.

An assessment of the renewable energy potential of oil palm residues: A case study of CDC plantation, Cameroon

Cameroon faces enormous clean energy accessibility challenges despite abundant energy resources and huge quantities of free oil palm residues (OPR) generated but dumped yearly from the agro-industrial companies like the Cameroon Development Corporation (CDC). Presently, electricity supply is mainly from hydro (73 %) with accessibility of 65 % and 14 % for urban and rural areas respectively, while energy mix is historically dominated by traditional biomass fuels such as firewood and charcoal, accounting for more than 76 % of the country's total energy consumption. The hydro supply is not regular as it depends on weather conditions and this has negatively impacted the economy. The situation is aggravated by the increased energy demand over the past decade as Cameroon has engaged to become an emerging economy by 2035. However, encouraging policies for researchers and investors in the energy sector have been put in place with a view of attaining a 25 % share of renewable energy (RE) by 2035. OPR are a potential (RE) resource but require technical assessment and technological transformation into clean energy rather than dumping, which constitutes a serious environmental problem. This research has assessed the quantity of OPR generated annually at the CDC and estimated its clean energy value from 2004 to 2018 by consulting fruits-harvest records from CDC statistics office and by bomb calorimetry respectively. The significant findings reveal a yearly production of 203666T of OPR with a calorific value of 896 TJ, corresponding to electrical energy potential of 249 MWh. The energy could be used by the industry or injected into the grid to mitigate the current energy challenges.

Determination of Energy Content of “Zero-Sugar” Artificial Sweeteners via Bomb Calorimetry and Theoretical Calculations

Determination of Energy Content of “Zero-Sugar” Artificial Sweeteners via Bomb Calorimetry and Theoretical Calculations

Generalizability of empirical correlations for predicting higher heating values of biomass

ABSTRACT Designing efficient biomass energy systems requires a thorough understanding of the physicochemical, thermodynamic, and physical properties of biomass. One crucial parameter in assessing biomass energy potential is the higher heating value (HHV), which quantifies its energy content. Conventionally, HHV is determined through bomb calorimetry, but this method is limited by factors such as time, accessibility, and cost. To overcome these limitations, researchers have proposed a diverse range of empirical correlations and machine-learning approaches to predict the HHV of biomass based on proximate and ultimate analysis results. The novelty of this research is to explore the universal applicability of the developed empirical correlations for predicting the Higher Heating Value (HHV) of biomass. To identify the best empirical correlations, nearly 400 different biomass feedstocks were comprehensively tested with 45 different empirical correlations developed to use ultimate analysis (21 different empirical correlations), proximate analysis (16 different empirical correlations) and combined ultimate-proximate analysis (8 different empirical correlations) data of these biomass feedstocks. A quantitative and statistical analysis was conducted to assess the performance of these empirical correlations and their applicability to diverse biomass types. The results demonstrated that the empirical correlations utilizing ultimate analysis data provided more accurate predictions of HHV compared to those based on proximate analysis or combined data. Two specific empirical correlations including coefficients for each element (C, H, N) and their interactions (C*H) demonstrate the best HHV prediction with the lowest MAE (~0.49), RMSE (~0.64), and MAPE (~2.70%). Furthermore, some other empirical correlations with carbon content being the major determinant also provide good HHV prediction from a statistical point of view; MAE (~0.5–0.8), RMSE (~0.6–0.9), and MAPE (~2.8–3.8%).

Physiological, temporal, and environmental determinants of dry energy densities of low trophic-level fishes in the Gulf of Mexico

Low trophic-level fishes provide a link to higher trophic-level animals, including birds, mammals, and economically valuable fishes. Despite their role, the dry energy density (DED) of these fishes and its variability have not been described in the northern Gulf of Mexico (nGOM). To address this, we describe species-specific DED for four fish species in the nGOM: Atlantic Croaker (Micropogonias undulatus), Gulf Menhaden (Brevoortia patronus), White Trout (Cynoscion arenarius), and Bay Anchovy (Anchoa mitchilli). We investigated the impacts of body length, life stage (juvenile and adult), month of collection, and river discharge from the Mississippi River to determine the response of DED for Atlantic Croaker and Gulf Menhaden. Using bomb calorimetry, we found that the DED of Atlantic Croaker ranged from 3021 to 6445 calories/g (mean = 4524 ± 646 calories/g SD, n = 129), Gulf Menhaden DED ranged from 2578 to 6821 calories/g (mean = 5069 calories/g ± 794 SD, n = 193), White Trout DED ranged from 3118 to 4581 calories/g (mean = 4120 calories/g ± 358 SD, n = 30), and Bay Anchovy DED ranged from 3925 to 4387 calories/g (mean = 4261 ± 126 calories/g SD, n = 74). The mean DED of Gulf Menhaden and Atlantic Croaker varied and was at a minimum during the fall. The DED of Gulf Menhaden and Atlantic Croaker were linearly, positively, and significantly (α = 0.05) related to fork length (R2 = 0.23 and R2 = 0.32, respectively). The flow rate of the Mississippi River was not a significant predictor of the DED of juvenile or adult Gulf Menhaden but was a significant predictor of the DED of adult Atlantic Croaker (p < 0.001, R2 = 0.04). The species-specific energy density values and the variations due to the month of collection, environmental conditions, and physiological variation will serve to inform ecosystem models.

Properties of RDF after Prolonged Storage

Increasing production of municipal solid waste (MSW) drives the need for its disposal in a manner that is safe for the environment and human health. However, this may require short- or long-term storage before it can be properly processed. Similarly, a way of processing waste material is necessary for the re-cultivation of dump sites. This article presents the results of an investigation into the effects of long-term open-air storage upon waste material to be turned into refuse-derived fuel (RDF) by standard methods for the assessment of MSW and RDF pellet quality including bomb calorimetry, sieve analysis, furnace drying/burning for water/ash content assessment, and pellet expansion measurements. Results of the investigation indicate that such a form of storage bears no notable negative effect on the quality of the material; the pellet expansion coefficient, heat of combustion, and ash content were all found to be approximate to pre-storage values, with positive implications for the storage of solid waste and the prospects of its subsequent processing into solid fuel. It is shown that such material can be stored in open-air conditions for prolonged periods without the loss of desired parameters. In addition, a discussion of differences between the properties of material drawn from varying depths of the pile is provided and the potential impact of the findings in the context of the production and the storage of refuse-derived fuel is assessed.

Thermochemistry of the dissolution of tetra-4-sulfophthalocyanine nickel in aqueous solutions KОН at 298.15 K

We have obtained a nickel tetra-4-sulfophthalocyanine complex, soluble in water. The standard enthalpies of formation of a compound can be considered as the sum of the additive group contributions of fragments of these molecules. We assessed this value using a method based on group systematics with a Benson-type classification of fragments, taking into account the influence of the primary environment of the atoms. In order to obtain the value of the contribution of Ecompl(N)4-Ni, we used the bomb calorimetry method. The enthalpy of combustion of tetrakis (4-methoxyphenyl) porphine and its complex with nickel tetrakis (4-methoxyphenyl) porphine nickel were experimentally determined. Thermal effects of dissolution of crystalline nickel tetra-4-sulfophthalocyanine in aqueous solutions of various KOH concentrations (from 0.002 to 0.02 mol∙L−1) at 298.15 K were determined by the direct calorimetric method. The measurements were carried out in a calorimeter with an isothermal shell equipped with a reaction vessel with a volume of 60 cm3, electric calibration at T = (293.15–308.15) ± 0.01 K and P = 100.5 ± 0.7 kPa, and automatic temperature registration. The standard enthalpy of formation of dissociation products of the tetra-4-sulfophthalocyanine complex with nickel in an aqueous solution has been calculated.

Novel Solid Propellants Enabled Through In Situ Martian Perchlorates

With evidence for the native perchlorates existing in the Martian regolith, this paper examines the feasibility and performance of propellants formed from perchlorate salts reported to be present on Mars. Thermochemistry calculations indicate that the Martian perchlorate-based propellants provide less theoretical specific impulse than AP composite propellants but could still be viable propellants. Three propellants made from Martian perchlorates were manufactured and compared to a control propellant with AP as the oxidizer. Deflagration experiments were performed to obtain the burning rates as a function of pressure, with results comparable to AP baseline propellant. The propellant energy density was evaluated through bomb calorimetry. The propellant formulation with a similar perchlorate mixture to the distribution found in Martian soil was then subjected to thermal analysis, elemental analysis, and sensitivity testing to examine its combustion behavior and suitability for handling. Further characterization and development work would be needed to field these propellants, but initial conclusions indicate an in situ blend of calcium perchlorate and magnesium perchlorate could serve as a novel oxidizer for future safe, high-performing, and economical solid propellant rocket motors, offering an alternative to most current proposals for Martian ascent vehicle architectures.

Beverage sample preparation and procedures for bomb calorimetry: Establishing equivalency in methods

Standardised bomb calorimetry methods (sample preparation and combustion techniques) are essential to accurately quantify the caloric value of food and beverages, yet no protocols exist. This study evaluated the influence of various methodological approaches to establish those most reliable for beverage calorie determination. Equivalence testing was used to verify if differences between means (and 90% CI) were within established margins. Standardised test beverages included a low- and high-fat version. Part A determined a coefficient of variation for establishment of equivalence margins; Part B assessed differences between calorimetry methods. Elements evaluated included: initial sample homogenisation, sample dehydration, post-dehydration homogenisation, sample presentation, sample weight, combustion pressure, and sample storage. Aspects that may be critical to reliably determine the gross energy content of beverages include initial agitation, dehydration level (%), post-dehydration homogenisation, pre-combustion sample presentation and sample storage time. Oven-dried high-fat samples had the largest deviations from equivalence, particularly those not agitated prior to dehydration or combustion, or not dehydrated to a constant weight. Some methods do not exhibit differences, such as low-fat sample pre- and post-dehydration homogenisation, dehydration method and temperature, sample weight, and combustion pressure. These findings identify critical aspects of sample preparation and combustion for the caloric determination of beverages.