Calorimetry Research Articles

Multiple element coupling and molecular-chemical diversity of organic matter control how much energy is retained in soils in mountain ecosystems

Organic matter is the primary repository of chemical energy driving biogeochemical cycles and maintaining ecological functions in soils. Therefore, revealing factors controlling energy in soils is critical but has less been studied so far. In this study, we investigated energy stored in soils and litter biomass, 12 elements level (macroelements including C, N, P, Fe, and K, microelements including Cu, Li, Mg, Mn, Ni, Pb, and Zn), and molecular-chemical composition of soil organic matter (SOM) among four vegetation zones along the elevation in the Changbai Mountain. The calorific values in soils (Qs) and litters (Ql) were determined using oxygen bomb calorimetry. The complexity of SOM was reflected by molecular diversity of pyrolytic products of SOM (SHID), and relations among 12 elements were represented by defining coupling extent (MEC). Potential impacts of MEC and SHID on energy stored in soils were discussed. Results indicated that the average Qs and Ql were 565 cal/g and 3799 cal/g, respectively. The proportion of Qs to Ql (Qr) ranged from 6.28 % to 43.65 % with a mean of 14.74 %. Significant differences in Qs and Ql were observed among four vegetation zones along the elevation. Significantly positive relations were observed between elevation and Ql, between MEC and Qr or Qs, and between Qs and SHID. The VPA analysis indicated that MEC itself could explain 19 % variation of Qs, and the exploration raised to 60 % when MEC was in conjunction with elevation, pH, and SHID. The structure equation model confirmed positive effects of MEC and SHID on Qs. In conclusions, MEC was primarily associated with energy holding by mountain soils, proving that a conceptual advance was required to link element biogeochemical cycle and energy flow in ecosystems, thereby bridging the potential gap between matter and energy in ecological research.

Accuracy of reported energy in food and beverages supplied to hospital patients.

Underprovision of food energy within the hospital environment can negatively affect clinical outcomes. Hence, the supply of hospital foods/beverages and the ability to assess their calorie provision is critical. The aim of this study was to directly measure the energy density of foods/beverages supplied to patients by Gold Coast University Hospital (GCUH) foodservice and compare these to caloric values established from nutrition information panels (NIPs) on product packaging. Bomb calorimetry was used to determine the gross energy density of 58 food/beverage items (~47% of total menu) using standardised procedures. Food items included those from the general menu, in addition to therapeutic menu items. Equivalence between directly measured values and those derived from NIPs was determined by comparing the measured mean and ±90% confidence interval (CI) against two pre-defined equivalence bounds (i.e., ±10% NIP value [consensus criteria] and ±20% NIP value [United States Food and Drug Administration (US FDA) criteria]). Caloric values from NIPs were considered equivalent to measured values when the 90% CI of the measured values fell within these thresholds. Overall, 34 (59%) and 19 (33%) items had measured energy density values not equivalent to those from product NIPs according to the consensus and US FDA thresholds, respectively. When employing the US FDA criteria, 12 (21%) items contained a higher calorie density than that established from the label, while seven (12%) items were lower. While non-equivalent items were identified across all therapeutic menus, food labels from items exclusively prepared for the smooth-pureed menu were particularly inaccurate (~60% non-equivalency). This study found a discrepancy between energy density that was directly measured and that derived from manufacturers' NIPs for many foods and beverages supplied via a hospital foodservice. Given the importance of accurate energy provision for hospitalised patients, this level of inaccuracy is concerning and may warrant a revision of food labelling procedures for items supplied in hospital settings.

Using Bomb Calorimetry to Investigate Intestinal Energy Harvest in Anorexia Nervosa: Preliminary Findings on Stool Calorie Loss.

Renourishment and weight restoration are critical first steps in anorexia nervosa (AN) treatment. The ability of the gastrointestinal tract to harvest and utilize energy from food is essential for successful weight restoration, but the functional capacity of the intestine after prolonged caloric restriction remains unknown. In an exploratory study, we quantified the stool energy content of individuals with AN before and after renourishment. We used archived stool samples from a multisite cohort (NCT03119272) of 103 individuals with AN at admission and discharge from inpatient renourishment and 122 sex-matched non-eating disorder controls (non-ED). To determine whether bomb calorimetry may have utility in AN, we measured stool calorie loss as the number of kilocalories per gram of stool. Analyses included ANOVA, paired/unpaired t-tests, and Spearman rank correlations for associations between stool energy and clinical variables. Following 25.10 ± 19.73 days of renourishment, patients gained an average of 5.67 ± 4.27 kg. Raw stool energy at discharge (AN-DIS: 5.72 ± 0.86 kcal/g) was significantly higher than admission (AN-AD: 5.41 ± 0.86 kcal/g; p < 0.01). Weight and BMI at admission and discharge were negatively correlated with raw stool energy at discharge. Energy content in stool increases after inpatient refeeding, likely due to increased calorie consumption. Findings should be interpreted cautiously due to methodological limitations in this post hoc study design. Future studies should use a priori, gold-standard protocols to investigate stool calorie loss in AN, as prolonged restriction in AN may disrupt the gut and impede energy harvest. clinicaltrials.gov: NCT03119272.

Properties of Hydrochar Derived from Arabica Coffee Agro-Industry Residues under Wet Torrefaction Method

This study utilized coffee cherry residues, which is an abundantly available source of biomass in Indonesia. One of the methods to utilize coffee plantation residues effectively is wet torrefaction. This method is well-known as a hydrothermal method, where the biomass conversion process uses liquid as a medium and reactant in the process. The objective of this work was to develop an effective procedure for converting coffee agro-waste into marketable products using hydrothermal technology. The information related to changes in physical and thermal properties were explored in this work. To achieve the research objectives, three main steps were performed, i.e., feedstock preparation, wet torrefaction, and hydrochar characterization. Two types of feedstocks were studied in this work, coffee parchment and coffee pulp. In the wet torrefaction process, each feedstock was treated using two types of solutions, i.e., distilled water and acetic acid, at different concentrations. The reaction was carried out in an autoclave with a pressure of 2 bar (g) and an operating temperature of 130 ℃ for 2 hours. The properties of the hydrochar products were then analyzed using various methods, including bomb calorimetry, SEM, density, TGA-DTG, and hydrophobicity analyses. Overall, the results indicated that the hydrochar produced under acetic acid solution had better characteristics compared to that treated under distilled water. In terms of fixed carbon content and calorific value, the values increased up to 25.3% and 4,603 kcal/kg, respectively. Enhanced hydrophobicity was only observed in the coffee parchment hydrochar, where the average time required to adsorb water was 146.6 s, which can be categorized as strongly hydrophobic.

Ignition and combustion properties of NGO coated AlH3

AlH3 is a highly promising additive for energetic materials and has gained considerable attention as a substitute fuel for aluminum in solid propellants. In order to improve its compatibility with energetic materials and oxidants, carbon coating materials are often used. Nitrated graphene oxide (NGO) was prepared and used as a surface modifier of α-AlH3 in our study. Various analytical techniques were utilized to examine its structure and morphology, including Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), particle size distribution (PSD) and X-ray diffraction (XRD). The oxidization, ignition characteristics, flame propagation behavior and heat of combustion of AlH3 and AlH3/NGO powder were investigated using differential thermal analysis (DTA), a laser igniter, a high-speed camera and an oxygen bomb calorimetry. Results show that NGO coating agent catalyzes the thermal decomposition and hydrogenation process of AlH3, and accelerates the oxidation process of AlH3. The addition of 4 % NGO decreases the oxidation activation energy of AlH3 by about 8.94 %. The laser ignition energy of AlH3/NGO is much lower than that of AlH3, and the ignition energy decreases linearly as NGO is added from 1 % to 10 %. The flame development process supports the good thermal conductivity assistance effect of an appropriate amount of NGO in the combustion process of AlH3 in air, which is consistent with the result of oxygen bomb test, indicating that the addition of NGO leads to an improvement in the combustion efficiency of AlH3.This may provide valuable insights for the development of new high-energy solid propellants.

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.

Preparation, characterization and thermal properties of nitrographene coated aluminum powder

AbstractAluminum powder is commonly used as a metal fuel additive in composite solid propellants. However, its tendency to agglomerate during combustion can lead to two‐phase flow losses, negatively impacting its energy performance. To address this issue and enhance the combustion performance of aluminum powder, nitrated graphene oxide (NGO) was developed to improve aluminum dispersion and optimize its energy characteristics. Various analytical techniques were employed to examine its properties, including Fourier‐transform infrared spectroscopy (FT‐IR), scanning electron microscopy (SEM), X‐ray photoelectron spectroscopy (XPS), elemental analysis (EA), differential scanning calorimetry (DSC), and thermogravimetric analysis (TG). Al/NGO composite was prepared using a solution‐assisted method in N, N‐dimethylformamide (DMF) and characterized by SEM, XPS and X‐ray diffraction (XRD). The ignition characteristics and heat of combustion of Al/NGO powder were measured using a laser igniter and an oxygen bomb calorimetry. The appropriate mass ratios of NGO coating had positive effects on the ignition and combustion of Al. Specially, 4 % NGO coating reduced Al ignition energy by 46.5 % and increased the Al combustion efficiency by 22.0 %. Moreover, the catalytic effect of Al/NGO on the thermal decomposition of ammonium perchlorate (AP) was investigated using differential thermal analysis (DTA). Results showed that two‐stage pyrolysis paths of AP tended to merge into a single pyrolysis process when Al/NGO4 % was added. The most favorable catalytic effect on AP′s thermal decomposition process was produced with the addition of 10 % Al/NGO4 %, reducing the activation energy by Kissinger equation for high‐temperature decomposition to 107.7 kJ mol−1. These findings may provide valuable insight for enhancing the performance of aluminum powder in energetic materials through NGO modification.

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