Energy Balance Analysis Research Articles

Energy balance analysis suggests that lactate is not a direct cause of the slow component of oxygen uptake kinetics.

The mechanisms of oxygen uptake ( ) slow component in the severe exercise intensity domain are still a matter of debate. We tested the hypothesis that the rate of blood lactate ([La]) accumulation above maximal lactate steady state (MLSS) is a major cause of slow component. On 13 males exercising on a cycle-ergometer, we measured gas exchanges, heart rate, and [La] during maximal incremental exercise test to determine maximal aerobic power ( max) and at constant power exercise tests at 60%, 65%, 70%, and 80% of max. Maximal was 3.19 ± 0.37l·min-1, max was 283 ± 28 W. At 60% max all variables attained steady state in all subjects. Power at MLSS was 177 ± 21 W. At 80% max a clear slow component was observed in all subjects, exercise lasted 11.3 ± 3.1min and [La] was 7.4 ± 2.2mmol at 5min and 11.5 ± 3.6mmol at 10min. The energy balance computed at 80% max resulted compatible with the principles of the energetics of muscular exercise, if we assume linear [La] increase, and thus constant metabolic power provided by [La] accumulation. Conversely, the metabolic power provided by slow component increases with time. This contrast is incompatible with the tested hypothesis that consequently must be rejected. This study excluded [La] accumulation as a main cause of slow component.

Research on the dynamic characteristics of micro-scale droplet impact

Micro-scale droplet impact behavior is widely observed and holds critical significance in various fields such as inkjet printing, anti-icing, and spray cooling. However, current research has primarily focused on millimeter-scale droplets, leading to a lack of understanding regarding the dynamics of micro-scale droplets. To address this gap, our research systematically analyzed the impact and rebound behaviors of droplets of various sizes on microstructur surfaces, revealing the significant influence of droplet size on dynamic characteristics. The results revealed that micro-scale droplets exhibit markedly distinct morphological evolution during spreading, contraction, and rebound compared to millimeter-scale droplets. As droplet size decreases, the minimum rebound velocity threshold significantly increases, contact time extends substantially, and viscous dissipation becomes the primary energy loss mechanism in micro-scale droplets, resulting in a dramatic decrease in the restitution coefficient. Based on energy balance analysis, we developed a theoretical model to characterize the restitution coefficient of micro-scale droplets, demonstrating strong concordance with the experimental results. This research provides novel insights into the dynamic behavior of micro-scale droplets and offers theoretical support for surface design in diverse applications such as biomedical printing, aircraft anti-icing, and electronic device cooling.

A benchmark of industrial polymerization process for thermal runaway process monitoring

Polymer production is of paramount importance in the chemical manufacturing industry. However, safety concerns are prevalent due to the exothermic nature of polymerization reactions, which can cause thermal runaway. The limitations of the current industry-standard monitoring methods underscore the need for novel techniques to detect faults early. To facilitate the development and evaluation of such algorithms, benchmarks that enable direct comparisons of performance are required. Addressing this gap, the present work first introduces an open-source polymerization benchmark model and associated datasets. Derived from reaction kinetics, mass balance, and energy balance analysis, the differential equation forms the basis of our model. By manipulating relative parameters, we intentionally induce five typical faults that can lead to thermal runaway. As a result, our benchmark model serves as an invaluable tool for advancing and validating algorithms for thermal runaway process monitoring, significantly enhancing the safety of the polymerization process. The effectiveness of the model and dataset is demonstrated by testing multivariate statistical process monitoring algorithms and deep learning algorithms.

Optimal Sizing, Energy Balance, Load Management and Performance Analysis of a Hybrid Renewable Energy System

This work utilizes the particle swarm optimization (PSO) for optimal sizing of a solar–wind–battery hybrid renewable energy system (HRES) for a rural community in Rivers State, Nigeria (Okorobo-Ile Town). The objective is to minimize the total economic cost (TEC), the total annual system cost (TAC) and the levelized cost of energy (LCOE). A two-step approach is used. The algorithm first determines the optimal number of solar panels and wind turbines. Based on the results obtained in the first step, the optimal number of batteries and inverters is computed. The overall results obtained are then compared with results from the Non-dominant Sorting Genetic Algorithm II (NGSA-II), hybrid genetic algorithm–particle swarm optimization (GA-PSO) and the proprietary derivative-free optimization algorithm. An energy management system monitors the energy balance and ensures that the load management is adequate using the battery state of charge as a control strategy. Results obtained showed that the optimal configuration consists of solar panels (151), wind turbine (3), inverter (122) and batteries (31). This results in a minimized TEC, TAC and LCOE of USD 469,200, USD 297,100 and 0.007/kWh, respectively. The optimal configuration when simulated under various climatic scenarios was able to meet the energy needs of the community irrespective of ambient conditions.

Environmental sustainability, energy efficiency and uncertainty analysis of agricultural residue-based bioethanol production: A comprehensive life cycle assessment study

Bioethanol produced from agro-residue provides a sustainable alternative to fossil fuels, mitigating pollution, reducing waste, and promoting a circular economy. However, challenges arise in sustainable sourcing, resource conflicts, water quality concerns, and managing environmental footprints to maximize agro-residue-based bioethanol benefits. The environmental impacts, net energy ratio (NER), net energy value, water footprint, and uncertainties associated with bioethanol production from agro-residues are analyzed in this study. The analysis followed a cradle-to-gate approach using 1 L of bioethanol produced as a functional unit (FU), allowing for a direct comparison of the environmental performance of the different feedstocks. The result shows that rice straw-based bioethanol exhibited higher environmental impacts, particularly in terms of ecotoxicity, ionizing radiation, human toxicity, and ozone layer depletion, except for greenhouse gas emission, which is lowest for corn stover (0.37 kg CO2 eq. per FU) and highest for cassava straw (1.1 kg CO2 eq. per FU). Furthermore, the Cumulative Energy Demand analysis highlighted a significant reliance on fossil fuels from agricultural biomass throughout the bioethanol production process. The energy balance analysis shows that the agricultural residues are feasible for bioethanol production with NER of 1.20, 3.10, and 3.28 for rice straw, corn stover, and cassava straw, respectively. To enhance the accuracy and reliability of the LCA results, Monte Carlo simulation was employed to account for uncertainty and variability in the data. This methodology provides a better understanding of the impacts of bioethanol production, with a focus on sustainability and advancements in reducing our reliance on fossil fuels.

Off-grid PV/biomass/DG/battery hybrid renewable energy as a source of electricity for a farm facility

Reliable, cost-effective energy systems are pivotal for sustainable development in the agricultural sector. Using the energy balance analysis of the Hybrid Optimization Model for Electric Renewable (HOMER), this study presents a techno-economic assessment of a hybrid renewable energy system for a farm facility. The energy system components considered in the analysis include solar photovoltaics, wind turbines, diesel generators, biomass, and battery storage. The results shows that ten feasible energy systems can technically power the typical farm facility, with a PV-Biomass-DG battery being the best in terms of the total net present cost. The PV-Biomass-DG-battery systems consist of 561.023 kW of PV, 88 kW of diesel generator, 10 kW of biomass, 81 kW of converter, and 584 batteries operated in a load-following mode. When the cost of energy (COE) of EA1 0.206325 $/kWh is compared to EA7 0.407681 $/kWh, a difference of $0.201356 will be saved for every kWh. Also, a comparison of the operating cost of EA1, $65,713.23 and the operating cost of EA7 $212,027.4 showed a margin of $146,314.17 being saved. Energy systems EA3 and EA4 had the lowest carbon dioxide production levels of 15.8 kg annually, respectively. The simple payback period metrics increased from EA1 to EA6 between 2.97 years to 6.99 years. The result of the study shows that adopting a low-carbon energy transition is technically and economically viable for the agricultural sector, especially in developing countries.

Dynamics of non-Newtonian droplets eccentrically impacting hydrophobic spherical surfaces

In this study, the dynamic behaviors of non-Newtonian fluid droplets with shear-thinning properties eccentrically impacting hydrophobic particle surfaces are investigated through a combination of numerical simulations and experiments. The simulation integrates the dynamic contact angle and a non-Newtonian fluid power-law model within the volume of fluid model framework. The effects of apparent viscosity (η), impact velocity (v0), and dimensionless eccentricity parameter (B) on the dynamic behaviors of non-Newtonian droplets are analyzed. Furthermore, the study offers insight into the progression of pressure distribution, kinetic energy, and liquid viscosity across droplets during the entire impact process. An energy balance analysis, which includes kinetic energy, surface energy, potential energy, and viscous dissipation, is employed to elucidate the fundamental physical mechanisms that govern the dynamics of eccentric impacts of non-Newtonian droplets. Finally, a model (Recr D* = −95.7 + 11 450.6e−B/0.18) is proposed to predict the adhesion or detachment of shear-thinning droplets eccentrically impacting hydrophobic particle surfaces.

Study on the Natural Ventilation Model of a Single-Span Plastic Greenhouse in a High-Altitude Area

The natural ventilation model plays a crucial role in greenhouse environmental control. It has been extensively studied by previous researchers, but it is limited to low-altitude areas. This study established a numerical model of single-span plastic greenhouses in high-altitude areas. The model was validated using measured data, showing a good agreement between the measured and simulated values. By setting boundary conditions based on on-site monitoring data, ventilation rates were extracted under different conditions for numerical simulations. Through nonlinear fitting, an empirical formula for natural ventilation rates, with a determination coefficient (R2) of 0.9724, was derived. The formula was validated through an energy balance analysis of indoor air. Different ventilation opening sizes were simulated to derive an empirical formula for natural ventilation rates based on opening size. Building on this, the relationship between plant height and ventilation rate was analyzed. As the dominant factors of natural ventilation change with environmental fluctuations, this study also proposed the threshold wind speed for wind pressure ventilation, thermal pressure ventilation, and coupled ventilation, filling the knowledge gap in relevant ventilation rate calculations. This is the first time that a natural ventilation model of single-span plastic greenhouses in high-altitude areas has been proposed, providing the basis in terms of modeling for the further development of local facility agriculture.

Optimizing mass flow and extracellular electron transfer to promote energy recovery during treating municipal wastewater in a biochar enhanced anaerobic membrane bioreactor (AnMBR)

The anaerobic membrane bioreactor (AnMBR) is an alternative technology with energy neutrality potential when treating municipal wastewater (MWW). However, the poor bio-reaction kinetic conditions caused by low COD concentrations in MWW greatly limits the CH4 yield. In this study, the average methanogenesis rate was significantly increased from 164.8 to 275.5 mL/g COD with the two times biochar addition of 5 g/L. And following the second time addition of 5 g/L biochar, the CH4 component significantly increased to a high level of 89.0 ± 6.3 %. In addition, the rate for acetate converted into CH4 increased from 3.3 to 10.5 mmol/(g VS·d) with biochar addition of 10 g/L, indicating that acetotrophic methanogenesis route was significantly promoted by biochar. Bio-electrochemistry analysis showed that biochar accelerated 0.74 mol e-/g VS/min of electron transfer velocity in AD system. The addition of biochar enriched organic metabolism bacteria such as Ancinetobacter_lwoffii, Comamonas and Geobacter, and upregulated the expression of functional genes related to organics degradation such as lldD, sucD and fumC, facilitates the direct transfer of electrons and acetates produced by Comamonas and Geobacter to convert CO2 into CH4 through microbial mediation. Thus, the COD flow shifted significantly towards more CH4 production. The COD mass flow showed that biochar facilitated more bio-catabolism (up about 52.7 %) and less bio-anabolism (down about 92 %), and more COD in wastewater was converted to CH4, resulting a significant promoting of energy production. The energy balance analysis indicated that the net energy consumption was reduced by 15 % after two times addition of 5 g/L biochar, and the key to achieve the net energy output during treating MWW is the efficient operation of AnMBR at ambient temperature.

Impacts of urban expansion on air temperature and humidity during 2022 mega-heatwave over the Yangtze River Delta, China

The Yangtze River Delta (YRD) experienced record-breaking heat in the summer of 2022. However, the urban heat pattern and the role of urban expansion over the last two decades in this hot summer have not been explored. Using the advanced mesoscale Weather Research and Forecasting (WRF) model, we reproduced the fine spatial features and investigated the urban heat island (UHI) and dry island (UDI) effects during the two identified heatwaves in 2022. We further replace the current (2020) land use with the historical (2001) land use in WRF to evaluate the impacts of urban expansion from 2001 to 2020 on air temperature and moisture. Our finding revealed that the conversion of land use resulted in near-surface warming and drying, with pronounced diurnal variations, especially during the July heatwave. The analysis of surface energy balance demonstrated that the substantial decrease in evapotranspiration (ET) was the primary driver of daytime warming, elevating temperatures by 7 °C (July heatwave) and 2 °C (August heatwave). This ET reduction also led to the strong daytime coupling of warming and drying effects over new urban areas. At night, the release of stored heat resulted in the temperature increase of 2 °C (1 °C) during July (August) heatwave, highlighting the nighttime as a critical period for heightened thermal risk. Additionally, urban expansion at the periphery contributed modestly to the warming of urban cores, exacerbating conditions in an already hot environment. This study enhances understanding of the impacts of urban expansion on air temperature and humidity during extreme heatwaves, thereby supporting targeted adaptation and mitigation for extreme events within large cities.

Numerical and experimental studies of a novel compact sandwich-type plate reactor for thermochemical energy storage

In this work, a novel compact sandwich-type plate reactor (CSPR) for thermochemical energy storage (TCES) with Ca(OH)2/CaO is proposed, where the essential unit is symmetrically comprised of steam channel in the center, orderly sandwiched by metal gauzes, reaction cavities, plates and heat transfer channels at both sides. Firstly, the flow-heat-reaction multi-field coupled modelling is conducted to comparatively investigate the flat, baffled and dimpled plates, where the dimpled plate (DP) stands out. Then, the entire CSPR comprised of three essential units with DPs is modelled to numerically predict its comprehensive performance and characteristics. Afterwards, the prototype of CSPR is manufactured based on the above numerical studies and experimentally evaluated on our exothermic and endothermic cycling performance test bench with loading of 1.667 kg of Ca(OH)2 pellets. The experimental data confirm that the charging stage takes 330 min with the final conversion up to 97.74 %, while the discharging stage takes 200 min with the maximal heat transfer fluid (HTF) output temperature reaching 385 ℃ and the duration for the HTF output temperature above 350 ℃ lasting for 130 min. Based on energy balance analysis, the energy storage efficiency for charging stage is 74.92 % and the round-trip energy efficiency for cycle is 60.24 % (including 2 h of buffering period) without heat recovery of product steam. Technically, these efficiencies can be respectively promoted to be 76.35 % and 71.59 % with heat recovery. The numerical simulation and experimental data are found to be mutually verified. We hope this work can provide a novel insight of reactor design for development of TCES technology.

Environmental, energy, and economic assessment of Jatropha curcas L. biodiesel production in China

Developing non-grain forestry woody fuel industries such as Jatropha curcas L. (JCL) aligns with the national conditions of countries with food shortages and large populations, such as some countries in Africa and Asia, and is an ideal alternative to replace fossil fuels. Determining appropriate planting densities suitable for different regions is one of the most critical practices for agriculture and forestry to achieve high yields and sustainability. This study conducted a life cycle assessment (LCA) of the JCL biodiesel's environmental impact, energy balance, and economic analysis (3E) of two densities and three of the most suitable planting regions in China. Findings reveal that the density of 2500 plants/ha had a better 3E performance than 1600 plants/ha, and Yunnan province outperformed Guizhou province and Sichuan province. JCL biodiesel effectively mitigates the greenhouse effect (1141.14–1936.59 kg CO2 eq/t) compared to conventional fossil diesel in different cases. Key factors influencing environmental performance include seed yield, urea applied during cultivation, methanol for biodiesel conversion, and electricity for irrigation. The Net Energy Balance (NEB) and Net Energy Ratio (NER) demonstrate the superior energy efficiency of JCL biodiesel over fossil diesel. The cost of producing JCL biodiesel decreased with the maturation of the trees, with water use and labor salary accounting for over 80% due to the necessity of the cultivation stage. Although the Financial Net Present Value (FNPV) was negative when considering only JCL biodiesel, it became positive (12111.64–27342.44 CNY) with the inclusion of by-products (glycerine, press-cake, and shells) in high-density cases. Our findings suggest that JCL biodiesel with appropriate density can serve as a sustainable biofuel alternative, replacing a portion of the fossil diesel currently on the market and significantly contributing to climate change mitigation and nonrenewable energy conservation.

Synergistic integration of hydrothermal pretreatment and co-digestion for enhanced biogas production from empty fruit bunches in high solids anaerobic digestion

This study investigates the co-digestion of hydrothermally pretreated empty fruit bunches (EFB) at 190 °C for 5 min (HTP190-EFB) with decanter cake (DC) to improve biogas production in high solid anaerobic digestion (HSAD). The HTP190-EFB exhibited a 67.98 % reduction in total solids, along with the production of 0.89 g/L of sugar, 2.39 g/L of VFA, and 0.56 g/L of furfural in the liquid fraction. Co-digestion of HTP190-EFB with DC at mixing ratios of 5, 10, and 15 %w/v demonstrated improved methane yields and process stability compared to mono-digestion of HTP190-EFB. The highest methane yield of 372.69 mL CH4/g-VS was achieved in the co-digestion with 5 %w/v DC, representing a 15 % increase compared to digestion of HTP190-EFB (324.30 mL CH4/g-VS) alone. Synergistic effects were quantified, with the highest synergistic methane yield of 77.65 mL CH4/g-VS observed in the co-digestion with 5 %w/v DC. Microbial community analysis revealed that co-digestion of hydrothermally pretreated EFB with decanter cake promoted the growth of Clostridium sp., Lactobacillus sp., Fibrobacter sp., Methanoculleus sp., and Methanosarcina sp., contributing to enhanced biogas production compared to mono-digestion of pretreated EFB. Energy balance analysis revealed that co-digestion of HTP190-EFB with DC resulted in a total net energy of 599.95 kW, 52 % higher than mono-digestion of HTP190-EFB (394.62 kW). Economic analysis showed a shorter return on investment for the co-digestion system (0.86 years) compared to the mono-digestion of HTP190-EFB (1.02 years) and raw EFB (2.69 years). The co-digestion of HTP190-EFB with 5 %w/v DC offers a promising approach to optimize methane yield, process stability, and economic feasibility, supporting the palm oil industry for producing renewable energy and sustainable waste management.

Intrinsic fracture toughness of a soft viscoelastic adhesive

The fracture toughness of inelastic materials consists of an intrinsic component associated with the crack tip fracture process and a dissipative component due to bulk dissipation. Experimental characterization of the intrinsic component of fracture toughness is important for understanding the fracture mechanism and predictive modeling of the fracture behavior. Here we present an experimental study on the intrinsic toughness of a soft viscoelastic adhesive. We first obtained full-field and full-history data of the displacement and deformation fields in pure shear fracture tests using a particle tracking method. By combining these data with a nonlinear constitutive model, we extracted the intrinsic toughness through an energy balance analysis. A two-stage crack propagation behavior was observed in our fracture experiments: under monotonic loading the crack first underwent a slow propagation stage and then suddenly entered a fast propagation stage. We found that the intrinsic toughness was highly scattered for the slow propagation stage, but remained consistent for the fast propagation stage. Further examination of the fracture surface and the onset of fast propagation revealed that transition from the slow to the fast propagation stage was governed by the applied stretch and was likely due to a change in the crack tip fracture process.

Understanding the energy and emission implications of new technologies in a kraft mill: Insights from a CADSIM Plus simulation model

Kraft mills play a vital role in energy transition because they have significant potential to reduce their own energy utilization and produce energy/products to decarbonize other sectors. Through biomass combustion and potential biogenic carbon emissions capture, these mills can contribute to offsetting emissions from other sectors. This research investigates the departmental and cross-departmental implications of technology upgrades on energy, steam, emissions, water, and chemicals using a CADSIM Plus simulation model. The model provides a comprehensive analysis of mass and energy balances, offering valuable insights into the benefits and limitations of each technology. The model facilitates scenario analysis and comparisons of process configurations, enabling data-driven decision-making for sustainable and competitive operations. Six high-impact technologies, including additional evaporator effects, weak black liquor membrane concentration, belt displacement washer for brownstock washing, oxygen delignification, and improvements to the pulp machine shoe press and vacuum pumps, are evaluated. Individual technologies resulted in energy savings of 1.2% to 5.4%, biomass consumption reductions of 8.6% to 31.6%, and total emissions reductions of 1.6% to 5.9%. Strategic decision-making must consider existing mill limitations, future technology implementation, and potential production increases. Future research will explore product diversification, biorefineries, and pathways to achieve carbon-negative operations, aiming to reduce emissions and secure a competitive future for kraft mills.

Evaluating the Energy Efficiency of Combining Heat Pumps and Photovoltaic Panels in Eco-Friendly Housing

This article aims to analyze the energy efficiency of combining heat pumps with photovoltaic (PV) panels in energy-efficient homes. The research methodology involved a detailed energy balance analysis, assessment of the impact of mechanical ventilation, location, heat loss, and the choice and operation of heat sources, with a particular focus on heat pumps in synergy with PV installations. The results demonstrate that integrating heat pumps with PV panels can significantly reduce the demand for external energy sources and lower the operating costs of buildings, while contributing to their energy self-sufficiency. This study highlights that such a combination of technologies is key to promoting sustainable development and achieving energy efficiency goals in the residential sector. The results of this analysis expand knowledge about the effectiveness of such systems and provide practical recommendations for designers and engineers interested in implementing renewable energy technologies in modern energy-efficient buildings, taking into account the impact of these solutions on reducing CO2 emissions as well.

Flash Pyrolysis of Waste Tires in an Entrained Flow Reactor-An Experimental Study.

In this study, a flash pyrolysis process is developed using an entrained flow reactor for recycling of waste tires. The flash pyrolysis system is tested for process stability and reproducibility of the products under similar operating conditions when operated continuously. The study is performed with two different feedstock materials, i.e., passenger car (PCT) and truck tire (TT) granulates, to understand the influence of feedstock on the yield and properties of the pyrolysis products. The different pyrolytic products i.e., pyrolytic carbon black (pCB), oil, and pyro-gas, are analyzed, and their key properties are discussed. The potential applications for the obtained pyrolytic products are discussed. Finally, a mass and energy balance analysis has been performed for the developed pyrolysis process. The study provides insight into the governing mechanisms of the flash pyrolysis process for waste tires, which is useful to optimize the process depending on the desired applications for the pyrolysis products, and also to scale up the pyrolysis process.

The phototrophic metabolic behaviour of Candidatus accumulibacter

The phototrophic capability of Candidatus Accumulibacter (Accumulibacter), a common polyphosphate accumulating organism (PAO) in enhanced biological phosphorus removal (EBPR) systems, was investigated in this study. Accumulibacter is phylogenetically related to the purple bacteria Rhodocyclus from the family Rhodocyclaceae, which belongs to the class Betaproteobacteria. Rhodocyclus typically exhibits both chemoheterotrophic and phototrophic growth, however, limited studies have evaluated the phototrophic potential of Accumulibacter. To address this gap, short and extended light cycle tests were conducted using a highly enriched Accumulibacter culture (95%) to evaluate its responses to illumination. Results showed that, after an initial period of adaptation to light conditions (approximately 4–5 h), Accumulibacter exhibited complete phosphorus (P) uptake by utilising polyhydroxyalkanoates (PHA), and additionally by consuming glycogen, which contrasted with its typical aerobic metabolism. Mass, energy, and redox balance analyses demonstrated that Accumulibacter needed to employ phototrophic metabolism to meet its energy requirements. Calculations revealed that the light reactions contributed to the generation of, at least more than 67% of the ATP necessary for P uptake and growth. Extended light tests, spanning 21 days with dark/light cycles, suggested that Accumulibacter generated ATP through light during initial operation, however, it likely reverted to conventional anaerobic/aerobic metabolism under dark/light conditions due to microalgal growth in the mixed culture, contributing to oxygen production. In contrast, extended light tests with an enriched Tetrasphaera culture, lacking phototrophic genes in its genome, clearly demonstrated that phototrophic P uptake did not occur. These findings highlight the adaptive metabolic capabilities of Accumulibacter, enabling it to utilise phototrophic pathways for energy generation during oxygen deprivation, which holds the potential to advance phototrophic-EBPR technology development.

Elucidating the Impact of Polyol Functional Moieties on Exothermic Poly(urethane-urea) Polymerization: A Thermo-Kinetic Simulation Approach

The pursuit of sustainable polyurethane (PU) product development necessitates a profound understanding of precursor materials. Particularly, polyol plays a crucial role, since PU properties are heavily influenced by the type of polyol employed during production. While traditional PUs are solely derived from hydroxyl functionalized polyols, the emergence of amine-hydroxyl hybrid polyols has garnered significant attention due to their potential for enhancing PU product properties. These hybrid polyols are characterized by the presence of both amine and hydroxyl functional groups. However, characterizing these polyols remains a daunting challenge due to the lack of established experimental testing standards for properties, such as fractional hydroxyl and amine moieties and thermo-kinetic parameters for amine reactions with isocyanates. Additionally, characterization methods demand extensive time and resources and pose risks to health and the environment. To bridge these gaps, this study employed computational simulation via MATLAB to determine the moieties’ fractions and thermo-kinetic parameters for hybrid polyols. The computational method integrated energy balance and reaction kinetics analysis for various polyols to elucidate the influence of functional moieties on the thermo-kinetic behavior of PU formations. Validation of the simulated results was conducted by comparing their experimental and simulated prepolymer and foam temperature profiles, highlighting the direct influence of fractional moieties on PU formations. The comparisons revealed an average relative error of less than 5%, indicating the accuracy and credibility of the simulation. Thus, this study represents a pivotal opportunity for advancing knowledge and driving sustainable developments in bio-based polyol characterization for PU production streamlining and formulation optimization.

Operational Matrix Framework for Energy Balance Analysis for Early Stage Design of Complex Vessels

Considering vital ship systems or distributed ship service systems at the early stage of complex vessels is a challenging task. The recent UCL Network Block Approach aimed to enable ship designer to address ship systems design synthesis simultaneously as a logical network using MATLAB with a CPLEX Toolbox in MATLAB and representative piping, cabling, and trunking routings on the physical description of the ship using a proven CASD tool PARAMARINESURFCON. This was possible due to adopting a set of frameworks, as part of this comprehensive approach. The paper presents one of the frameworks: the Operational Matrix, to formulate distributed ship service systems network in the early stage design of complex vessels. The application of the framework could take on many forms and can be manipulated to suit a specific distributed ship service system’s design. In this paper, a tutorial is given, leading from the simplest application of the Operational Matrix Framework to an example of a complex Operational Matrix application for the 3D multiplex submarine systems problem. The use of the proposed Operational Matrix Framework is shown to reveal the relationship between objective functions, constraints, bounds, and solutions of that linear programming formulation. The Operational Matrix Framework can enable the solvers (CPLEX Toolbox in MATLAB) to be very efficient in advancing early stage ship design applications. The Framework could be developed further for investigating the analysis of energy balances for new systems to achieve net zero energy demands for future naval vessels.