Search Results (67)

This study developed sustainable biocomposites composed of polylactic acid (PLA) and surface-treated pineapple core powder (PACP), fabricated via extrusion and fused deposition modelling (FDM). PACP loadings of 1–3 vol% were combined after chemical modification with NaOH and silane to improve interfacial bonding. Particle morphology showed increased porosity and surface roughness following treatment. The melt flow index (MFI) increased from 31.56 to 35.59 g/10 min at 2 vol% PACP, showing improved flowability. Differential scanning calorimetry (DSC) showed the emergence of cold crystallization (T_cc ~121 °C) and an increase in crystallinity from 35.7% (neat PLA) to 47.3% (2 vol% PACP). Thermogravimetric analysis showed only slight decreases in T₅ and T_max, showing the thermal stability. The mechanical testing of extruded filaments showed increased modulus (1463 to 1518 MPa) but a decrease in tensile strength and elongation. For the 3D-printed samples, elongation at break increased slightly at 1–2 vol% PACP, likely because of the improvement in interlayer fusion. Though, at 3 vol% PACP, the mechanical properties declined, consistent with filler agglomeration observed in SEM. Overall, 2 vol% PACP offered the optimal balance between printability, crystallinity, and mechanical performance. These results reveal the possibility of PACP as a value-added biowaste filler for eco-friendly PLA composites suitable for extrusion and 3D printing applications. Full article

Objectives: The purpose of this study is to quantitatively evaluate the combined effects of sports massage, blood flow restriction (BFR), and cold therapy on quadriceps recovery in mixed martial arts (MMA) athletes following eccentric exercise, focusing on muscle biomechanical properties, pain, and strength. Methods: This randomized, single-blind clinical trial involved 36 men and women MMA-trained participants, divided into three groups: massage (n = 12) received massage, BFR/cool (n = 12) received combined BFR and cooling, and control (n = 12) received passive rest as a control. The fatigue protocol involved MMA fighters performing five sets of plyometric jumps on a 50 cm box until exhaustion, with 1-min breaks between sets. After that, the massage group received a 20-min massage overall using standardized techniques; BFR/cool underwent a 20-min alternating blood flow restriction (200 mmHg) and cooling treatment with ice bags on the quadriceps; and the final group served as the control group with passive rest and no intervention. Participants were assessed four times—before exercise, immediately after exercise, 24 h post-exercise (after two recovery sessions), and 48 h post-exercise (after four recovery sessions)—for perfusion unit (PU), muscle elasticity, pressure pain threshold (PPT), reactive strength index (RSI), and total quality recovery (TQR). Results: The statistical analysis revealed significant effects of both massage and BFR/cooling interventions across key recovery outcomes, with large effect sizes for time-related changes in RSI (p < 0.0001; η² = 0.87), elasticity (p < 0.0001; η² = 0.84), and PPT (p < 0.0001; η² = 0.66). Notably, post-exercise 48 h values for RSI, elasticity, PU, and TQR were significantly improved in both the massage and BFR/cool groups compared to control (p < 0.05)), while no significant group differences were observed for PPT. Conclusions: The study concludes that both massage and combined blood flow restriction with cooling interventions significantly enhance post-exercise recovery—improving muscle perfusion, elasticity, reactive strength, and perceived recovery—compared to passive rest. Full article

The development of alternative energies has become a concern for all countries to ensure domestic energy supply and provide environmental friendliness. One of the providential alternative energies is biodiesel. Biodiesel, commonly stated as fatty acid alkyl ester (FAAE), is a liquid fuel intended to substitute petroleum diesel. Nevertheless, implementation of pure biodiesel is not recommended for conventional diesel engines. It holds poor values of cold flow properties, as the effect of high saturated FAAE content contributes to this constraint. Several processes have been proposed to enhance cold flow properties of biodiesel, but this work focuses on the skeletal isomerization process. This process rearranges the skeletal carbon chain of straight-chain FAAE into branched isomeric products to lower the melting point, related to the good cold flow behavior. This method specifically requires an acid catalyst to elevate the isomerization reaction rate. And then, sulfated tin(IV) oxide emerged as a solid superacid catalyst due to its superiority in acidity. The results of biodiesel isomerization over this catalyst and its modification with iron had not satisfied the expectation of high isomerization yield and significant CFP improvement. However, they emphasized that the skeletal isomers demonstrated minimum impact on biodiesel oxidation stability. They also affirmed the role of an acid catalyst in the reaction mechanism in terms of protonation, isomerization, and deprotonation. Furthermore, the metal promotion was theoretically necessary to boost the catalytic activity of this material. It initiated the dehydrogenation of linear hydrocarbon before protonation and terminated the isomerization by hydrogenating the branched carbon chain after deprotonation. Finally, the overall findings indicated promising prospects for further enhancement of catalyst performance and reusability. Full article

Energy storage stations (ESSs) need to be charged and discharged frequently, causing the battery thermal management system (BTMS) to face a great challenge as batteries generate a large amount of heat with a high discharge rate. Supercritical carbon dioxide (SCO₂) is considered a promising coolant because of its favorable properties, including non-flammability, high dielectric strength and low cost for the BTMS. The heat of a battery can be absorbed to a great extent if there is a small temperature rise because as the fluid temperature approaches a pseudo-critical temperature, the specific heat capacity of SCO₂ reaches its peak. In this study, a periodic model of the unit BTMS is established, and a numerical simulation is implemented to investigate the effects of different boundary conditions on the heat dissipation of a battery pack. The flow and heat transfer characteristics of SCO₂ in the liquid cold plate (LCP) of a battery pack with an extreme discharge rate are revealed. The results show that SCO₂ is more preferably used as a coolant compared to water in the same conditions. The maximum temperature and the temperature difference in the battery pack are reduced by 19.22% and 79.9%, and the pressure drop of the LCP is reduced by 40.9%. In addition, the heat transfer characteristic of the LCP is significantly improved upon increasing the mass flow rate. As the operational pressure decreases, the pressure drops of SCO₂ decrease in the LCP. Overall, the maximum temperature and the temperature difference in the battery pack and the pressure drops of the LCP can be effectively controlled by using a coolant made out of SCO₂. This study can provide a reference for the design of BTMSs in the future. Full article

Ground-source heat pump (GSHP) systems with medium-depth and deeply buried pipes in cold regions are highly important for addressing global climate change and the energy crisis because of their efficient, clean, and sustainable energy characteristics. However, unique geological conditions in cold climates pose serious challenges to the heat transfer efficiency, long-term stability, and adaptability of systems. This study comprehensively analyses the effects of various factors, including well depth, inner-to-outer tube diameter ratios, cementing material, the thermal conductivity of the inner tube, the flow rate, and the start–stop ratio, on the performance of a medium-depth coaxial borehole heat exchanger. Field tests, numerical simulations, and sensitivity analyses are combined to determine the full-cycle thermal performance and heat-transfer properties of medium-depth geological formations and their relationships with system performance. The results show that the source water temperature increases by approximately 4 °C and that the heat transfer increases by 50 kW for every 500 m increase in well depth. The optimization of the inner and outer pipe diameter ratios effectively improves the heat-exchange efficiency, and a larger pipe diameter ratio design can significantly reduce the flow resistance and improve system stability. When the thermal conductivity of the cementing cement increases from 1 W/(m·K) to 2 W/(m·K), the outlet water temperature at the source side increases by approximately 1 °C, and the heat transfer increases by 13 kW. However, the improvement effect of further increasing the thermal conductivity on the heat-exchange efficiency gradually decreases. When the flow rate is 0.7 m/s, the heat transfer is stable at approximately 250 kW, and the system economy and heat-transfer efficiency reach a balance. These findings provide a robust scientific basis for promoting medium-deep geothermal energy heating systems in cold regions and offer valuable references for the green and low-carbon transition in building heating systems. Full article

Background/Objectives: Colorectal cancer (CRC) remains a leading cause of cancer-related mortality, necessitating the development of effective preventive strategies. Fenugreek (Trigonella foenum-graecum) possesses well-documented pharmacological properties; however, its chemopreventive potential in colorectal cancer (CRC) remains unexplored. This study evaluates the efficacy of methanolic fenugreek seed extract (FSE) in an azoxymethane (AOM)-induced murine colorectal cancer (CRC) model, focusing on the modulation of oxidative stress, regulation of biomarkers, induction of apoptosis, and maintenance of epithelial integrity. Methods: FSE was extracted using cold maceration (yield: 24%) and analyzed by gas chromatography–mass spectrometry (GC-MS), identifying 13 bioactive compounds, including benzene, 1,3-dimethyl-; 1,3-cyclopentadiene, 5-(1-methylethylidene)-; o-Xylene; benzenepropanoic acid, 3,5-bis(1,1-dimethylethyl)-4-hydroxy-; and benzene, 1,2,3-trimethyl-. All 13 compounds identified were matched with the NIST library with high confidence. Molecular docking was used to assess the interactions of FSE bioactives with E-cadherin–β-catenin complexes. Swiss albino mice received an FSE pre-treatment before AOM induction and continued this treatment three times weekly for 21 weeks. Key assessments included survival analysis, body weight changes, serum biomarker levels (GGT, 5′-NT, LDH), antioxidant enzyme activities (SOD, CAT, GPx1, MDA), reactive oxygen species (ROS) quantification, apoptosis detection via flow cytometry, and immunofluorescence-based evaluation of E-cadherin dynamics. Results: FSE improved survival rates, mitigated AOM-induced weight loss, and dose-dependently reduced serum biomarker levels. Antioxidant enzyme activity was restored, while MDA levels declined. A dose-dependent increase in ROS facilitated apoptosis, as confirmed by flow cytometry (16.7% in the low-dose FSE group and 34.5% in the high-dose FSE group). Immunofluorescence studies revealed that FSE-mediated restoration of E-cadherin localization counteracted AOM-induced epithelial disruptions. Conclusions: FSE exhibits potent chemopreventive potential against CRC by modulating oxidative stress, regulating key biomarkers, inducing apoptosis, and restoring epithelial integrity. These findings support further investigations into its clinical relevance for CRC prevention. Full article

To address the limitations of poly (lactic acid) (PLA), it was blended with poly (methyl methacrylate) (PMMA) as a toughening component, using MgO nanoparticles (NPs, 0.075–0.15 wt%) as a catalyst. SEM pictures confirmed the good miscibility of the blends. Mechanical tests showed a slight decrease in elastic modulus and tensile strength for the PLA/PMMA125 sample containing 0.125% MgO. Yet, elongation at break rose by over 60% and impact strength increased by over 400% compared to pure PLA. Also, MgO facilitated the shifting of the glass transition temperature (T_g) of both polymers in DSC curves. Additionally, the absence of cold crystallization in PLA, coupled with reductions in its melting temperature (T_m) and crystallinity, were identified as critical factors contributing to improved miscibility within the reactive blend. Melt flow index (MFI) evaluation indicated a decrease in viscosity, while water contact angle measurements revealed an increase in polar groups on the surfaces of the MgO-containing samples. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses confirmed the effective distribution and dispersion of NPs throughout the blend, along with a significant decrease in crystallinity. Moreover, DFT calculations were performed to better understand the role of MgO in the reaction. The findings offered key insights into the reaction mechanism, confirming that MgO plays a crucial role in facilitating the transesterification between PLA and PMMA. These findings underscore the enhanced performance of exchange reactions between the active groups of both polymers in the presence of MgO, leading to the formation of PLA-PMMA copolymers with superior miscibility and mechanical properties. Finally, a cell culture assay confirmed the blend’s non-toxicity, showing its versatile potential. Full article

Geothermal energy is typically produced from underground reservoirs using water as the working fluid to transfer heat energy to surface and eventually to the delivery point. CO₂ has been proposed as an alternative working fluid due to its improved mobility, density and its supercritical phase state, leading thus to so-called CPG (CO₂ Plume Geothermal) systems. As a positive side effect, the injected CO₂ mass circulation in the reservoir can be considered a CO₂ storage mechanism, which, depending on the size of the porous medium, may account for few millions of CO₂ tons. Moreover, the thermosiphon effect, owned to the significant change of fluid density between the injection (cold) and the production wells (hot) as well as to its change along the wells, significantly reduces the need for pumping, hence the operating costs. In this work, we setup a mathematical model that fully describes flow in the production/injection wells doublet as well as in the geothermal reservoir. Subsequently, the model is used to evaluate the sensitivity of the beneficial effects of circulating CO₂ rather than water. Parameters such as reservoir properties, injection temperature and thermal effects, are tweaked to demonstrate the sensitivity of each one to the system performance. The results can be utilized as a guideline to the design of such systems and to the emphasis needed to be paid by the engineers. Full article

Microchannel liquid-cooled plates are widely used in high-performance electronic devices, but their heat transfer performance and pressure drop characteristics face complex challenges in the design process. In this paper, a counter-flow rectangular microchannel liquid-cooled plate is designed, and the effects of velocity, aspect ratio, and inlet/outlet forms on its heat transfer and pressure drop performance are investigated through orthogonal tests and numerical simulations. The results indicate that the velocity plays a crucial role in determining the plate’s performance. While increasing the velocity substantially enhances heat transfer efficiency, it also causes a steep rise in pressure drop. The aspect ratio has a lesser effect on the performance than the velocity, and smaller aspect ratios help to achieve a balance between thermal and flow properties. The comprehensive optimization of the inlet and outlet forms and velocity has a significant effect on the temperature uniformity and pressure drop, and the design of the cooling fluid inlet and outlet form of CM (side inlet and middle outlet) can effectively improve the temperature distribution and reduce the pressure drop at high velocity. The design parameters with the best overall performance are the aspect ratio of 2, the velocity of 0.5 m/s, and the CM inlet/outlet form (K2V0.5CM). Comparison with other design parameter sets verified that this parameter set showed significant advantages in cooling effect, temperature uniformity, flow and heat transfer performance. Finally, the correlation equation on Nu is established, and the simulated Nu as well as the calculated Nu are compared. In this thesis, a counter-flow rectangular microchannel cold plate is designed to optimize the flow rate, channel structure and other parameters through orthogonal tests to reduce the temperature gradient and balance the heat transfer and flow resistance to meet the demand for efficient heat dissipation of 350 W CPU. This study provides an important reference for the structural optimization of microchannel liquid-cooled panels and the engineering application of high-efficiency heat dissipation systems. Full article

The rising demand for edible oils underscores the potential of non-edible oils for biodiesel production. However, biodiesel’s low oxidative stability (OS) and poor cold flow properties due to high unsaturation levels limit its use. This study aims to improve OS through the partial hydrogenation of polyunsaturated FAMEs using a Ru-TPPTS biphasic catalytic system. GC-MS analysis showed that the pre-hydrogenated biodiesel contained over 85% of unsaturated FAMEs, mainly linoleic (C18:2) and oleic acid (C18:1). Hydrogenation reduced C18:2 FAME content by over 70% while increasing stearic acid level (C18:0 FAME), significantly enhancing OS by more than 135%. Further optimization is needed to meet the required quality and performance standards. Full article

The encapsulation of bacteria in emulsion droplets offers various advantages over other conventional methods of encapsulation, such as improvements in bacterial viability, and may serve as microenvironments for bacterial growth. Nevertheless, changes in temperature may affect bacterial viability and droplet stability. In this study, the encapsulation of bacteria in single water-in-oil (W/O) and double water-in-oil-in-water (W₁/O/W₂) emulsions under cold storage and temperature-modulated release were investigated. The microencapsulation of bacteria in emulsion droplets was achieved by using a flow-focusing microfluidic device. Droplet stability was determined by measuring changes in droplet size and creaming behaviour at different temperatures. The thermal properties of the samples were determined by using differential scanning calorimetry, while the release of bacteria with changes in temperature was determined by measuring the colony form unit (CFU) of the released bacteria and conducting fluorescence microscopy. Higher bacterial viability was observed for encapsulated samples compared to free cells, indicating the ability of the emulsion system to improve bacterial viability during cold-temperature storage. The crystallisation temperature was lowered in the presence of bacteria, but the melting temperature was similar with or without bacteria. Storage in freezing temperatures of −20 °C and −80 °C led to extensive droplet destabilisation, with the immediate release of encapsulated bacteria upon thawing, where the temperature-modulated release of encapsulated bacteria was achieved. This study provides an overview of the potential application of emulsion droplets for bacterial encapsulation under cold-temperature storage and the controlled release of encapsulated bacteria mediated by changes in temperature, which is beneficial for various applications in industries such as food and pharmaceuticals. Full article

In this research work, the feasibility of using fusel oil, a by-product of the sugar–alcohol industry, as an LVLC solvent in blends with straight vegetable oils (SVOs) and diesel was investigated. Concretely, diesel/fusel oil/sunflower oil (D/FO/SO) and diesel/fusel oil/castor oil (D/FO/CO) triple blends were prepared and characterized by measuring the most important physicochemical properties, i.e., viscosity, density, cold flow properties, flash point and cetane number. An appreciable improvement in cold flow values has been achieved with triple blends, without compromising properties such as calorific value and cetane number. Likewise, the triple blends meet the viscosity and density requirements specified by the European quality standard EN 14214 and the American standard ASTM D6751. After characterization, the triple blends were used on a diesel engine, evaluating different parameters such as power output, opacity, exhaust emissions (CO and NO_x) and consumption at different engine loads. The results indicate that as the biofuel content in the blend increases, engine power decreases while fuel consumption rises. Nevertheless, the values obtained with D/FO/CO are better than those for D/FO/SO and are also very similar to those of fossil diesel. Regarding opacity values and NO_x emissions obtained with the utilization of the triple blends, they are lower than those produced by diesel. However, in the case of CO emissions, it depends on the type of oil used, with the samples prepared with castor oil exhibiting the best results. Full article

Far infrared radiation (FIR) within the wavelength range of 4–14 μm can offer human health benefits, such as improving blood flow. Therefore, additives that emit far infrared radiation have the potential to be incorporated into polymer/fabric matrices to develop textiles that could promote health. In this study, biochar derived from candlenuts and pyrolyzed with activated carbon (AC) was incorporated into polypropylene (PP) films and investigated for its potential as a health-promoting textile additive. The properties of biochar were compared with other far infrared (FIR) emitting additives such as hematite, Indian red ochre, and graphene. The addition of biochar increased FIR emissivity to 0.90, which is 9% higher than that of pristine PP. Additionally, biochar enhanced UV and near-infrared (NIR) blocking capabilities, achieving an ultra-protection factor (UPF) of 91.41 and NIR shielding of 95.85%. Incorporating 2 wt% biochar resulted in a 3.3-fold higher temperature increase compared to pristine PP after 30 s of exposure to an FIR source, demonstrating improved heat retention. Furthermore, the ability to achieve the lowest thermal effusivity among other additives supports the potential use of biochar-incorporated fabric as a warming material in cold climates. The tensile properties of PP films with biochar were superior to those with other additives, potentially contributing to a longer product lifespan. Additionally, samples with red ochre exhibited the highest FIR emissivity, while samples with hematite showed the highest capacity for UV shielding. Full article

This article provides a comprehensive overview of ice-jam flood forecasting methodologies applicable to rivers during freezing. It emphasizes the importance of understanding river ice processes and fluvial geomorphology for developing a freeze-up ice-jam flood forecasting system. The article showcases a stochastic modelling approach, which involves simulating a deterministic river ice model multiple times with varying parameters and boundary conditions. This approach has been applied to the Exploits River at Badger in Newfoundland, Canada, a river that has experienced several freeze-up ice-jam floods. The forecasting involves two approaches: predicting the extent of the ice cover during river freezing and using an ensemble method to determine backwater flood level elevations. Other examples of current ice-jam flood forecasting systems for the Kokemäenjoki River (Pori, Finland), Saint John River (Edmundston, NB, Canada), and Churchill River (Mud Lake, NL, Canada) that are operational are also presented. The text provides a detailed explanation of the processes involved in river freeze-up and ice-jam formation, as well as the methodologies used for freeze-up ice-jam flood forecasting. Ice-jam flood forecasting systems used for freeze-up were compared to those employed for spring breakup. Spring breakup and freeze-up ice-jam flood forecasting systems differ in their driving factors and methodologies. Spring breakup, driven by snowmelt runoff, typically relies on deterministic and probabilistic approaches to predict peak flows. Freeze-up, driven by cold temperatures, focuses on the complex interactions between atmospheric conditions, river flow, and ice dynamics. Both systems require air temperature forecasts, but snowpack data are more crucial for spring breakup forecasting. To account for uncertainty, both approaches may employ ensemble forecasting techniques, generating multiple forecasts using slightly different initial conditions or model parameters. The objective of this review is to provide an overview of the current state-of-the-art in ice-jam flood forecasting systems and to identify gaps and areas for improvement in existing ice-jam flood forecasting approaches, with a focus on enhancing their accuracy, reliability, and decision-making potential. In conclusion, an effective freeze-up ice-jam flood forecasting system requires real-time data collection and analysis, historical data analysis, ice jam modeling, user interface design, alert systems, and integration with other relevant systems. This combination allows operators to better understand ice jam behavior and make informed decisions about potential risks or mitigation measures to protect people and property along rivers. The key findings of this review are as follows: (i) Ice-jam flood forecasting systems are often based on simple, empirical models that rely heavily on historical data and limited real-time monitoring information. (ii) There is a need for more sophisticated modeling techniques that can better capture the complex interactions between ice cover, water levels, and channel geometry. (iii) Combining data from multiple sources such as satellite imagery, ground-based sensors, numerical models, and machine learning algorithms can significantly improve the accuracy and reliability of ice-jam flood forecasts. (iv) Effective decision-support tools are crucial for integrating ice-jam flood forecasts into emergency response and mitigation strategies. Full article

Significant concerns over energy security and environmental impact reduction will drive all stakeholders to generate proper alternative energies. Biodiesel is a prospective cleaner-burning biofuel that can contribute on addressing these concerns globally. Presently, pure biodiesel (B100) application is still facing several obstacles, principally in terms of its cold flow properties. Improvement in cold flow behavior parameters is the solution to promoting biodiesel implementation at a higher percentage and wider environmental temperature range. This study provides a detailed review of several improvement methods, both physical, chemical, and biological, from various scientific sources, to elevate the cold fluidity characteristics of biodiesel. The investigated methods convincingly offer proper enhancement in the cold flow properties of biodiesel. Mostly, this improvement is accompanied by an alleviation in oxidation stability, cetane number, and/or viscosity. However, the skeletal isomerization method presents promising cold fluidity refinement with minimal reduction in other physical properties. Therefore, the continuous development of these methods promises global sustainable application of high-quality biodiesel. Full article