Search Results (2,348)

Soy protein isolate (SPI) microgels were produced via heat-set gelation (4, 6, 8, and 10% by mass) followed by ultrasonication (400 W, 70% amplitude, 3 or 6 min) and used as stabilizers of oil–water emulsions (10% oil phase). The SPI concentration and ultrasonication time affected microgel size (236–356 nm) and polydispersity (0.253–0.550). The physical stability of the emulsions stabilized with 6 and 8% SPI microgels (6 min of ultrasonication) was evaluated for 14 d, influencing on the average size, creaming index and instability index of the emulsions, where those with 6% SPI microgels resulted in a major stability. The emulsions produced with these microgels encapsulated beta-carotene and were incorporated into whole yogurt at three concentrations: 5 (YE5), 10 (YE10), and 15% (YE15). The addition of the emulsions did not affect the physicochemical or microbiological quality of the yogurt. Rheological tests revealed that the yogurt behaved as a non-Newtonian and pseudoplastic fluid, with yogurts with more emulsions being less viscous. Sensory evaluation revealed consumer acceptance regarding color and texture; however, the perception of residual flavor was proportional to the amount of emulsion added. SPI microgels are effective stabilizers for β-carotene-loaded emulsions and a promising strategy for this compound delivery in yogurt. Full article

Amaranth is important for the agro-industrial complex. However, when extracting flour and oil from seeds, a lot of waste remains. Waste recycling by co-pyrolysis aims at obtaining new products with high added value. This study examined a combination of A. cruentus (AC) residues and low-density polyethylene (LDPE) waste. The addition of polymer was aimed at obtaining hydrocarbon-rich pyrolysis liquid and biochar. Pyrolysis was performed on an experimental setup, along with thermogravimetry–Fourier infrared spectroscopy–gas chromatography mass spectrometry (TG-FTIR-GC MS), to examine the thermochemical conversion. Experiments were carried out using a thermogravimetric analyzer at heating rates of 5, 10, and 20 °C/min. The average activation energy values for the pyrolysis of the AC/LDPE blend by the Ozawa–Flynn–Wall (OFW) and Kissinger–Akahira–Sunose (KAS) techniques were 301.39 kJ/mol and 287.69 kJ/mol, respectively. A visual examination of the correlations of the kinetic parameters of AC/LDPE was carried out using the Kriging method. The pyrolysis liquid from AC contains 38.14% hydrocarbons, with the main part being aliphatic hydrocarbons. During the pyrolysis of the AC/LDPE mixture, hydrocarbons were found in the resinous and waxy organic fractions of the pyrolysis liquid. The composition and properties of AC and AC/LDPE biochar are similar, and they can both be applied to agriculture. Full article

This study investigated meat analogs produced by high-moisture extrusion from mixtures of pea protein isolate and soryz flour, and chickpea flour and hazelnut meal in a 1:1 ratio, at two distinct heating temperature profiles: 40-60-80-100 °C and 60-80-100-120 °C. Physicochemical indicators, texture and chromatic parameters, protein digestibility, and antioxidant activity of the meat analogs were assessed, and antioxidant activity of the product in terms of simulating gastrointestinal digestibility in vitro was performed. The results obtained for the analyzed meat analog indicators were greatly influenced by the type of plant-based raw material used and the heating temperature profiles. A higher temperature regime leads to a slight decrease in the content of nutritive compounds in the final products. All meat analog samples showed good water and oil holding capacity. A decrease in hardness was observed for the mixtures compared to pea protein isolate, which can be attributed to protein content. The digestibility of the processed meat analog proteins ranged between 86.84% and 69.37%. PCA was applied to illustrate the relationships between physicochemical characteristics, protein digestibility, antioxidant activity, texture profile analysis, and CIELab color parameters in high-moisture meat analogs. Full article

The United States produces approximately 500 million tons of asphalt mixtures annually, while generating vast amounts of waste materials that could be repurposed for sustainable infrastructure. Each year, 1.4 billion gallons of lubricating oils are available for reuse and recycling. Additionally, 280 million tires are discarded, contributing to significant environmental challenges. Given the critical role of the roadway network in economic growth, mobility, and infrastructure sustainability, there is a pressing need for innovative material solutions that integrate recycled materials without compromising performance. This study introduces a Rubberized-Aerogel Composite (RaC), a novel asphalt binder modifier combining crumb rubber, recycled oil, and a silica-based aerogel to enhance the sustainability and durability of asphalt pavements. The research methodology involved blending the RaC with the PG70-10 asphalt binder at a 5:1 ratio and conducting comprehensive laboratory tests on binders and mixtures, including rheology, thermal conductivity (TC), specific heat capacity (Cp), the Hamburg Wheel-Tracking Test (HWTT), and indirect tensile strength (IDT). Pavement performance was simulated using AASHTOWare Pavement ME under hot and cold climates with thin and thick pavement structures. Results showed that RaC-modified binders reduced thermal conductivity by up to 30% and increased specific heat capacity by 15%, improving thermal stability. RaC mixtures exhibited a 50% reduction in rut depth in the HWTT and lower thermal expansion/contraction coefficients. Pavement ME simulations predicted up to 40% less permanent deformation and 60% reduced thermal cracking for RaC mixtures compared to the controls. RaC enhances pavement lifespan, reduces maintenance costs, and promotes environmental sustainability by repurposing waste materials, offering a scalable solution for resilient infrastructure. Full article

Ready-to-eat products are very popular and controversial due to their microbial safety. The main processing steps in obtaining a safe, edible product is heat treatment. The traditional manufacturing of meatballs, which conducts unhealthy compounds related to deep-fat-fried foods like the oil oxidation of harmful substances and polycyclic aromatic hydrocarbons, has been replaced with baking (180 °C) and steaming (94 °C). The addition of aqueous extract from two herbs, lemon balm (Melissa officinalis L.) or wild thyme (Thymus serpyllum L.), has led to twelve variants of meatballs, obtained from the tenderloin of three different animal species (pork, turkey, and beef). During processing, the food components go through conformational changes that affect the texture of the final product. In this study, differential scanning calorimetry for detecting and characterizing the thermal changes in meatballs was used. In addition, the influence of heat treatments on the textural and rheological parameters of meatballs was evaluated using instrumental methods. The cooking yield registered values of 61.21 ± 0.25% for steamed beef samples and 81.36 ± 0.86% for steamed turkey samples. The latest samples also showed the lowest firmness value, 3.41 ± 0.79 N. In this study, the addition of aqueous extracts did not considerably affect the texture and rheological behavior, which were influenced mainly by the heat treatment and meat type. Generally, steaming determined a firmer texture compared to baking. Full article

This study investigates the influence of key heat treatment parameters on the microstructure and mechanical properties of the powder metallurgy tool steel Vanadis 60. A fractional factorial design of experiments was applied to evaluate the effects of austenitising temperature, quenching medium, tempering temperature, and number of tempering cycles on hardness, flexural strength, and microstructure, using detailed phase characterisation by X-ray diffraction. The results reveal two distinct processing routes tailored to different performance objectives. Maximum hardness was achieved by combining austenitisation at 1180 °C, rapid oil quenching, and tempering at 560 °C. These conditions enhance the solubility of carbon and other alloying elements, promote secondary hardening, and reduce retained austenite. Conversely, higher toughness and ductility were obtained by austenitising at 1020 °C, air cooling, and tempering at 560 °C. These parameters favour the formation of a bainitic microstructure, together with lower martensite tetragonality and minimal retained austenite. A statistically significant interaction was identified between the austenitising temperature and the number of tempering cycles; three temperings were sufficient to compensate for the lower hardness associated with reduced austenitising temperatures. The results provide a robust guidance for optimising thermal processing in highly alloyed tool steels, enabling the precise tailoring of microstructure and properties in accordance with specific mechanical service requirements. Full article

The heat exchanger in a hydropower unit plays a critical role in ensuring the stability of the unit and improving operational efficiency. This paper conducted a global flow-field/heat-transfer numerical analysis of multi-tube heat exchangers in hydropower units (with 98 tubes) and applied it to optimization research under actual operating conditions. Using a three-dimensional two-phase flow model, this work systematically analyzes the effects of different sand content and particle size on heat-transfer performance, revealing the impact of particle-flow and fluid-flow nonuniformity on heat-exchange efficiency. This research fills the gap in existing studies regarding the analysis of the impact of complex operating conditions on hydropower unit radiators. To address the issues of nonuniform flow fields and poor flow mixing in existing heat exchangers, an improved inlet/outlet structural-optimization plan is proposed. The original cylindrical inlet/outlet is replaced with a square structure, and its area is increased. The optimized structure improves flow uniformity, reduces flow losses, enhances heat-transfer performance by 7.7%, and achieves a significant reduction of 0.53 K in oil temperature. The findings of this study provide theoretical and engineering guidance for the design and optimization of heat exchangers in hydropower units and are of high value for practical applications. Full article

This study investigates the thermal performance of an oil-jet-cooled permanent magnet synchronous motor (PMSM), with a particular focus on end-winding heat dissipation. A high-fidelity numerical model that preserves the full geometric complexity of the end-winding is developed and validated against experimental temperature data, achieving average deviations below 7%. To facilitate efficient parametric analysis, a simplified equivalent model is constructed by replacing the complex geometry with a thermally equivalent annular region characterized by calibrated radial conductivity. Based on this model, the effects of key spray ring parameters—including orifice diameter, number of nozzles, inlet oil temperature, and flow rate—are systematically evaluated. The results indicate that reducing the orifice diameter from 4 mm to 2 mm lowers the maximum winding temperature from 162 °C to 153 °C but increases the pressure drop from 205 Pa to 913 Pa. An optimal nozzle number of 12 decreases the peak winding temperature to 155 °C compared with 162 °C for 8 nozzles, while increasing the oil flow rate from 2 L/min to 6 L/min reduces the peak winding temperature from 162 °C to 142 °C. Furthermore, a non-uniform spray ring configuration decreases maximum stator, winding, spray ring, and shaft temperatures by 5.6–9.2% relative to the baseline, albeit with a pressure drop increase from 907 Pa to 1410 Pa. These findings provide quantitative guidance for optimizing oil-jet cooling designs for PMSMs under engineering constraints. Full article

In this study, non-isothermal pyrolysis of a mixture of disposable surgical face masks (FMs) and nitrile gloves (NGs) was conducted, using a heating rate of 100 °C/min, N₂ flowrate of 100 mL/min, and temperatures between 500 and 800 °C. Condensable product yield peaked at 600 °C (76.9 wt.%), with gas yields rising to 31.0 wt.%, at 800 °C. GC-MS of the condensable product confirmed the presence of aliphatic compounds (>90%), while hydrogen, methane, and ethylene dominated the gas composition. At 600 °C, gasoline (C₄ to C₁₂)-, diesel (C₁₃ to C₂₀)-, motor oil (C₂₁ to C₃₅)-, and heavy hydrocarbon (C₃₅₊)-range compounds accounted for 23.7, 46.7, 12.5, and 17.1%, of the condensable product, respectively. Using model-free methods, the average activation energy and pre-exponential factor were found to be 309.7 ± 2.4 kJ/mol and 2.5 ± 3.4 × 10²⁵ s⁻¹, respectively, while a 2-dimensional diffusion mechanism was determined. Scale-up runs confirmed high yields of condensable product (60–70%), with comparable composition to that obtained from lab-scale tests. The pyrolysis oil exceeds acceptable oxygen, nitrogen, chlorine, and fluorine levels for industrial steam crackers—needing pre-treatment—while other contaminants like sulphur and metals could be managed through mild blending. In summary, this work offers a sustainable approach to address the environmental concerns surrounding disposable FMs and NGs. Full article

In response to the growing demand for lightweight and high-efficiency industrial equipment, this study addresses the critical issue of lubrication failure in high-speed, heavy-duty gear reducers, which often leads to reduced transmission efficiency and premature mechanical damage. A three-dimensional transient multiphysics-coupled model of oil-jet lubrication is developed based on computational fluid dynamics (CFD). The model integrates the Volume of Fluid (VOF) multiphase flow method with the shear stress transport (SST) k−ω turbulence model. This framework enables the accurate capture of oil-jet interface fragmentation, reattachment, and turbulence-coupled behavior within the gear meshing region. A parametric study is conducted on oil injection velocities ranging from 20 to 50 m/s to elucidate the coupling mechanisms between geometric configuration and flow dynamics, as well as their impacts on oil film evolution, energy dissipation, and thermal management. The results reveal that the proposed method can reveal the dynamic evolution characteristics of the gear injection lubrication. Adopting an appropriately moderate injection velocity (30 m/s) improves oil film coverage and continuity, with the lubricant transitioning from discrete droplets to a dense wedge-shaped film within the meshing zone. Optimal lubrication performance is achieved at this velocity, where oil shear-carrying capacity and kinetic energy utilization efficiency are maximized, while excessive turbulent kinetic energy dissipation is effectively suppressed. Dynamic monitoring data at point P further corroborate that a well-tuned injection velocity stabilizes lubricant-velocity fluctuations and improves lubricant oil distribution, thereby promoting consistent oil film formation and more efficient heat transfer. The proposed closed-loop collaborative framework—comprising model initialization, numerical solution, and post-processing—together with the introduced quantitative evaluation metrics, provides a solid theoretical foundation and engineering reference for structural optimization, energy control, and thermal reliability design of gearbox lubrication systems. This work offers important insights into precision lubrication of high-speed transmissions and contributes to the sustainable, green development of industrial machinery. Full article

Contemporary climate challenges and energy security issues once again demonstrate that the transition to alternative motor fuels is a key and priority task for ensuring sustainable development in European Union countries, as well as in Ukraine. This review provides a comparative analysis of the physical, chemical, and performance properties of biodiesel fuels derived from 17 lipid-based feedstocks, including vegetable oils, animal fats, food industry waste, and microalgae. This study investigates the influence of fatty acid composition and transesterification alcohol type on key fuel properties, including density, viscosity, cetane number, pour point, heat value, and flash point. The results show that biodiesel fuels with a high content of saturated fatty acids exhibit higher cetane numbers and energy content, while biodiesel fuels with a high content of unsaturated fatty acids possess improved viscosity and cold flow properties. Camelina, rapeseed, and used cooking oil are identified as being particularly promising feedstocks based on their performance and availability in the European and Ukrainian dimensions. These findings are supported by a SWOT analysis and cost–benefit comparison, providing practical insights into the feasibility and scalability of biodiesel production pathways. Full article

As part of the energy transition needed to mitigate global warming, the study and sustainable exploitation of geothermal resources—a largely underutilized form of energy and heat production—is crucial. The availability of subsurface data acquired for oil and gas exploration purposes provides an opportunity to reconsider these data to enhance the use of geothermal potential. This is the case of a fractured carbonate reservoir in the Southern Apennines (Italy). All available subsurface data were gathered, homogenized, and reinterpreted to build a 3D geological model of the study area, where a positive thermal anomaly is known, yet the mechanisms and pathways of heat transport were previously unclear. By integrating subsurface, temperature, and literature data, a geological model is proposed that explains how high temperatures and heat propagation are closely linked to specific geological features. By cross-referencing and weighing the relevance of data for geothermal purposes, an attempt is made to rank the geothermal potential of existing wells in the area. This study demonstrates how a well-constrained geological model and the joint analysis of multidisciplinary data can provide the necessary knowledge base for conducting further technical, engineering, and economic analyses to assess the commercial viability of the identified geothermal resource. Full article

Pyrolysis of oily sludge (OS) faces two significant challenges, dehydration in emulsion and coke formation, which cause extra energy consumption. Targeting energy saving, this paper first reported on solar photothermal dehydration and confined catalytic pyrolysis of OS using a single material. A wood sponge loaded with carbon dots (CM-CDs) can generate heat by absorbing solar energy and promote rapid phase separation and water transport via capillary action of oil–water emulsion in OS under sunlight. Almost all free water in OS with varied content can be removed after 3 h. Hydrocarbons entered the internal space of CM-CDs instead of contacting with soil minerals, contributed to the subsequent confined catalytic pyrolysis, led to a reduction in Ea (35.61 kJ/mol), inhibited coking and caking, and yielded higher oil recovery efficiency. In addition, CDs can form hotspots to enhance pyrolytic behaviors in local regions. When the ratio of OS to CM-CDs reached 10:0.6, the recovery rate of the oil fraction through combined pyrolysis was as high as 89%, which was 17% higher than that of OS pyrolysis alone. This discovery provides a new way to solve the bottleneck problems of OS pyrolysis in the industry. Full article

This research contributes to advance the sustainable production of biofuels and provides insights into the energy and exergy assessment of bio-oil, which is essential for developing environmentally friendly energy production solutions. Energy and exergy analyses were performed to evaluate the pyrolysis of beech wood biomass at 500 °C in an Auger reactor. To improve the quality of the obtained bio-oil, its catalytic deoxygenation was performed within an in-line fluidized catalytic bed reactor using a catalyst based on HZSM5 zeolite modified with 5 wt.% Iron (5%FeHZSM-5). A thermodynamic analysis of the catalytic and non-catalytic pyrolysis system was carried out, as well as a comparative study of the calculation methods for the energy and exergy evaluation for bio-oil. The required heat for pyrolysis was found to be 1.2 MJ/kg_biomass in the case of non-catalytic treatment and 3.46 MJ/kg_biomass in the presence of the zeolite-based catalyst. The exergy efficiency in the Auger reactor was 90.3%. Using the catalytic system coupled to the Auger reactor, this efficiency increased to 91.6%, leading to less energy degradation. Calculating the total energy and total exergy of the bio-oil using two different methods showed a difference of 6%. In the first method, only the energy contributions of the model compounds, corresponding to the major compounds of each chemical family of bio-oil, were considered. In contrast, in the second method, all molecules identified in the bio-oil were considered for the calculation. The second method proved to be more suitable for thermodynamic analysis. The novelties of this work concern the thermodynamic analysis of a coupled system of an Auger biomass pyrolysis reactor and a fluidized bed catalytic deoxygenation reactor on the one hand, and the use of all the molecules identified in the oily phase for the evaluation of energy and exergy on the other hand. Full article

The involute gear with variable tooth thickness lacks established methods for calculating meshing heat and studying oil-jet lubrication and cooling effects. This study aims to theoretically estimate the meshing heat generated during the engagement process of involute gears with variable tooth thickness. To achieve this, a heat calculation model is derived based on the corresponding tooth surface equations. The impact of oil-jet lubrication parameters—jet velocity, pitch cone angle, face width ratio, and axial displacement—on the gear surface temperature and internal gearbox environment is systematically studied. Numerical simulations of the temperature field are validated through experimental measurements. The results indicate that an oil-jet velocity of 15 m/s combined with a pitch cone angle of 4° significantly reduces both gear surface and internal flow field temperatures. Additionally, smaller face width ratios and axial displacements effectively lower the internal temperature of the gearbox. These findings offer a theoretical basis for calculating meshing heat and designing oil-jet lubrication systems for variable-tooth-thickness involute gears. Full article