Search Results (18,468)

In this study, a techno-economic and carbon footprint (GHG, CO₂-equivalent) analysis was conducted on two alternative biofuels, green diesel and bio-jet fuel, produced from renewable lipids. The focus of the work is the comparison of various lipid feedstocks, including waste cooking oil, and four types of vegetable oils: cardoon, soybean, palm, and sunflower. Process optimization and design were performed to minimize production costs by using the process simulation software Aspen Plus^®. Green diesel and bio-jet fuel were obtained via hydrodeoxygenation and hydroisomerization/hydrocracking, respectively. Sensitivity analyses confirmed consistent results across the tested vegetable oils. Hydrodeoxygenation achieved triglyceride molar conversions exceeding 97%, with overall mass yields into the diesel fraction surpassing 79%. Conversely, hydroisomerization/hydrocracking of green diesel resulted in over 90% conversion of n-paraffins and more than 50% overall mass yield. The economic analysis showed that the primary cost factor influencing the payback selling price of the biofuels is the price of the lipid feedstocks. Biofuels are economically viable only when lipid prices are below 1000 €/ton and hydrogen prices are below 3000 €/ton. An important aspect is also represented by the combined-cycle energy recovery system, which strongly affects the overall capital cost and increases internal power generation efficiency. The carbon footprint calculated over a cradle-to-grave boundary showed shows net GHG reductions versus the fossil reference fuels for all scenarios. Net avoided emissions range from 1.74 to 3.63 kgCO₂-eq/kg green diesel and from 0.80 to 3.70 kgCO₂-eq/kg bio-jet fuel across the investigated feedstocks, approximately 40–84% and 20–95% of the respective savings relative to the fossil reference fuels under the stated background and logistics assumptions. Results are expressed per kg of produced fuel as a functional unit, using literature-derived upstream emission factors for oil supply and background inputs (hydrogen, Italian grid electricity and transport). For the bio-jet configuration, co-product burdens were partitioned by mass; the Discussion section highlights the sensitivity of the GD vs. BJF comparison to co-product handling and allocation choices. In this context, the choice of feedstock is essential in establishing the resulting GHG intensity of the two biofuels. From both economic and climate change perspectives, waste cooking oil emerges as the most promising option, particularly given its classification as waste-derived feedstock in the system boundary, unlike the virgin oil sources. Full article

As a primary reaction medium, water profoundly influences the kinetics and mechanisms of chemical processes. External physical treatments, such as vibration, can alter the physicochemical properties of water, thereby modifying reaction outcomes. This study aimed to investigate the effect of vibrational iterations (I0–I7) prepared using the “crossing” technology on the kinetics of the oxidation–reduction reaction between methylene blue and ascorbic acid, a standard model for evaluating external influences. Initial characterization revealed that while pH remained stable across all samples, electrical conductivity and dissolved oxygen levels deviated significantly from the control (intact water), with oxygen concentrations measuring either higher or lower than the control. Following the dissolution of methylene blue in these iterations, absorption spectroscopy was used to monitor decolorization kinetics. Different vibrational iterations influenced distinct kinetic parameters, including the rate constant, half-reaction time, and average reaction rate. Depending on the number of processing steps used to prepare the iterations, these parameters exhibited deviations ranging from 3% to 9% compared to the control. This suggests a complex relationship between the aqueous medium’s structural–dynamic properties and the reactants’ supramolecular organization. These findings underscore the potential of vibrational iterations as a tool for modulating chemical reaction kinetics through aqueous medium engineering. Further research is needed to elucidate the underlying mechanisms and expand the applicability of this approach to other systems. Full article

Silicon-based materials offer exceptional theoretical capacity for lithium-ion batteries (LIBs), but their practical application remains severely hindered by large volume expansion, low electrical conductivity, and unstable solid electrolyte interphase (SEI) formation during cycling. Herein, a binder-free silicon-containing carbon composite anode (denoted as CP-Si@C-4, where CP represents the conductive carbon paper substrate) is designed: carbon constitutes the structural and conductive framework, while silicon nanoparticles serve as a functional alloying component contributing characteristic lithiation/delithiation behavior. This framework comprises a conductive carbon paper (CP) scaffold, a resin-derived carbon matrix for homogeneous silicon dispersion, an interconnected carbon nanotube (CNT) network enabling long-range electron transport, and a conformal chemical vapor deposition (CVD) carbon layer for interfacial stabilization. Rather than simply increasing the overall carbon content, a series of control electrodes with distinct carbon configurations are deliberately designed to decouple the respective roles of bulk stress buffering and particle-level interfacial stabilization during cycling. The results indicate that functionally differentiating and coordinately regulating these two functions is critical for achieving durable binder-free silicon-containing carbon composite anodes. Benefiting from this cooperative multidimensional carbon architecture, the optimized CP-Si@C-4 anode delivers an initial Coulombic efficiency (ICE) of 86.3% and maintains a reversible capacity of ~990 mA h g⁻¹ at 2 A g⁻¹ after 1000 cycles. This work provides a structural design concept for improving long-term stability in binder-free silicon-containing carbon composite anodes. Full article

Due to environmental challenges, the global luxury hospitality industry faces increasing pressure to reduce its consumption of natural resources while maintaining service quality. In this paper a conceptual study is conducted to identify three primary problems of the tourism industry and highlight their impact on sustainable water resources and ecosystems: excessive water, electricity and towel/linen consumption in luxury hotels and resorts. This paper proposes a solution that uses a digital smart meter system linked to guest rooms. It is activated upon check-in, and guest participation is optional. It uses tangible or intangible incentives—such as discounts upon departure for future stays or for hotel laundry/meals/beverages—that rationalize consumption without affecting the quality of basic services. This approach may be implemented either independently by a single hotel or collaboratively through strategic alliances among multiple hotels, thus enabling customers to redeem their incentives/credits at any participating property. Guests are grouped into three consumption levels: high-saving guests (high incentives), average-saving guests (average incentives) and third-level guests (low/below-average incentives). Adopting this approach helps luxury hotels/resorts reduce their operational costs and enhance their image by applying green marketing in practice. Moreover, this conceptual paper proposes the provision of badges, including international environmental certifications, to hotels that adopt this responsible approach. This mechanism is a modern model that directly benefits all involved parties: service providers, customers/guests, environmental organizations and the environment. Full article

This paper presents an analysis of the dynamic parameters of vehicles powered by an electric drive unit based on a permanent magnet synchronous motor (PMSM) and a conventional drive system based on a spark-ignition combustion engine. The research subjects were a Mercedes-Benz EQA 250+ and an Audi A3 8V 35 TFSI with a turbocharged 1.5 dm³ engine. The paper presents an analysis of changes in power and torque as a function of engine speed (ICE) and driving speed of the electric vehicle (BEV). The study demonstrated fundamental differences, primarily the progression of the external characteristic curves of the engines and changes in vehicle dynamics. The research shows differences in the elasticity depending on the type of the drive motor. The research was conducted using a chassis dynamometer that allowed for a deeper understanding of the operation of the electric vehicle drive system and the identification of significant differences and dependencies in the external characteristics. Full article

Intensive Care Unit Acquired Weakness (ICUAW) is a highly prevalent neuromuscular complication affecting around 40% of critically ill patients, rising to over 80% in high-risk cohorts. It is independently associated with prolonged mechanical ventilation, increased intensive care unit (ICU) and hospital length of stay, elevated mortality (in-hospital, 1-year, and 5-year), higher healthcare costs, and long-term functional impairment. ICUAW is clinically defined by symmetric flaccid tetraparesis, frequently involving respiratory muscles, and exhibits significant pathobiological heterogeneity. Further subclassification is based on neurotopographic patterns: Critical Illness Polyneuropathy (CIP), Myopathy (CIM), and Polyneuromyopathy (CIPNM). Diagnosis typically relies on the Medical Research Council (MRC) Sum Score, with a threshold of <48 indicating clinically relevant weakness. While adjunct modalities such as electromyography/nerve conduction studies support assessment, their utility may be limited by patient cooperation and availability. Preventive strategies center on modifiable metabolic factors. Caloric and protein deficits exacerbate catabolism, while overfeeding—linked to anabolic resistance and stress hyperglycemia—also impairs recovery. To date, pharmacologic interventions remain inconclusive. However, early mobilization and neuromuscular electrical stimulation are promising non-pharmacologic strategies. The multifactorial and heterogeneous pathophysiology of ICUAW highlights the need for a biologically refined definition that can guide future targeted therapeutic interventions. Comprehensive multimodal strategies, together with structured long-term follow-up in Post-Intensive Care Syndrome (PICS) clinics, are essential for improving outcomes in this prevalent complication of critical care. Full article

The influence of different voltage measurement and current injection configurations on the quality of image reconstruction in electrical impedance tomography (EIT) was investigated using numerical simulations. Adjacent and opposing techniques were systematically used to examine their effectiveness in voltage acquisition and current delivery. The simulation model employed 16 equally spaced electrodes arranged around a circular domain, with an injected alternating current of 1 mA at a frequency of 50 kHz. A circular object with a conductivity of 0.9 units was sequentially positioned at five distinct locations within the imaging domain, each spaced 0.05 units apart. The reconstructed images were analyzed for positional accuracy and contrast resolution. While each configuration offers specific advantages, they exhibit inherent limitations depending on the application. The results of this study enable the understanding of the trade-offs involved in selecting electrode drive and measurement strategies for optimizing image quality in EIT systems. Full article

Welding copper (Cu) and aluminum (Al) is highly demanded for lightweight and cost-effective manufacturing. However, it faces significant challenges. First, substantial differences in physical properties may lead to high residual stresses and distortion. Second, brittle intermetallic compounds (IMCs) readily form at the interface, severely compromising the joint’s mechanical properties and electrical conductivity. Third, the native oxide film on Al impedes effective wetting and bonding. Therefore, effective control over the interfacial microstructure of the welded joint is essential. This review provides a critical analysis and comparison of several typical welding techniques, including laser welding (LW), friction stir welding (FSW), ultrasonic welding (UW), brazing and soldering, and welding–brazing. These analyses focus on their process characteristics, joint microstructures, and corresponding formation mechanisms. Furthermore, this review synthesizes key strategies for enhancing joint quality, including process parameter optimization, introduction of functional interlayers, and external assistance, aimed at optimizing joint microstructure and minimizing defects. Based on the analysis, this work provides comparative insights into process selection and microstructure control, and highlights future directions: advancing novel methods such as magnetic pulse welding and transient liquid phase bonding; developing intelligent real-time process control to suppress brittle IMCs and associated defects; promoting sustainable practices and establishing standardized performance evaluation; and systematically investigating long-term reliability to support the industrial application of robust Cu/Al joints. Full article

Elastomer-based nanocomposites combining polymer flexibility with conductive nanofillers provide lightweight, stretchable systems with tunable electromechanical properties for wearable electronics, soft robotics, and self-powered sensors. However, predicting their nonlinear response remains challenging because the observed piezoelectric-like response arises from strain-dependent interfacial polarization and evolving piezoresistive conduction pathways within heterogeneous microstructures. We introduce a continuum electro-hyperelastic framework combining the Mooney–Rivlin model for large-strain elasticity with a Helmholtz free-energy approach for electrostatic coupling. Analytical expressions for stress, electric displacement, and apparent piezoelectric coefficients are derived and implemented in finite element simulations. The model accurately reproduces the experimental mechanical, dielectric, and electromechanical behaviour of polydimethylsiloxane (PDMS) nanocomposites with 0.1–1 wt% graphene. These show increased stiffness, relative permittivity (from 3.4 to 4.0, ≈18%), and quasi-static d₃₃ coefficients (from −5.6 to −10.0 pC N⁻¹, ≈80% enhancement). Analytical and finite element method (FEM) results show consistent trends across the full deformation range, with Maxwell stress agreement within 10% at lower deformation levels, while deviations of 33–40% for coupled electromechanical quantities at an axial displacement u_z = ~−1 mm (~16.7% compressive strain) are attributable to three-dimensional shear effects absent from the uniaxial analytical assumption. Simulations reveal that graphene boosts Maxwell stress, yielding a four-fold increase at lower stretch ratios. This reframes PDMS–graphene composites as electro-hyperelastic materials, offering a predictive, extensible framework. It highlights apparent piezoelectricity as an emergent, tunable effect from charge redistribution in a compliant hyperelastic matrix—guiding the design of next-generation flexible devices leveraging field-induced coupling over intrinsic polarization. Full article

Soil salinization is a widespread form of land degradation that severely constrains agricultural productivity and ecosystem stability. Efficient and transferable monitoring methods are therefore essential for large-scale salinization assessment. Remote sensing provides timely and synoptic observations, while the integration of multi-source datasets offers complementary spectral and spatial information. In this study, we developed a cross-platform spectral index specifically for soda saline–alkali (carbonate/bicarbonate-dominated) soils by integrating laboratory spectra and hyperspectral satellite observations through a collaborative, cross-dataset spectral feature selection framework. Dual-band spectral indices were constructed from transformed reflectance spectra, and a stepwise coupled correlation analysis was applied to identify representative candidates that consistently exhibited strong associations with log-transformed soil electrical conductivity (logEC) across datasets. An optimal central-wavelength analysis was then performed to determine a stable and transferable band pair. The study was conducted in the Songnen Plain of Northeast China using laboratory-measured soil spectra and Ziyuan-1 02D Advanced Hyperspectral Imager data, and the proposed index was further validated using Landsat-8 and Sentinel-2 Multispectral data. Results show that the proposed Difference Index based on Square Root Reflectance at 520 nm and 900 nm (DISRR520900) exhibited consistent relationships with logEC (R = 0.60 for hyperspectral satellite data and R = 0.82 for laboratory spectral data), outperforming commonly used salinity indices in terms of cross-sensor stability. The spatial distribution of soil salinization derived from DISRR520900 is highly consistent with true-color imagery, and multi-source data fusion further improves mapping continuity and spatial coverage. It should be noted that the proposed index is primarily applicable to bare or sparsely vegetated soil surfaces in soda saline–alkali regions. Under dense vegetation cover, substantial crop residue, or wet surface conditions, additional masking or correction may be required. These results demonstrate that DISRR520900 provides a stable cross-sensor solution for large-scale soil salinization mapping within comparable soil chemical contexts. Full article

Background: Obstructive sleep apnea (OSA) is a highly prevalent and heterogeneous disorder associated with substantial cardiometabolic morbidity. Although continuous positive airway pressure (CPAP) remains first-line therapy, long-term effectiveness is frequently limited by suboptimal adherence. Advances in airway devices, surgical techniques, neuromodulation, and pharmacologic therapies have expanded the therapeutic landscape and created opportunities for individualized, mechanism-based treatment. Methods: We conducted a selective, narrative review with structured quantitative synthesis of randomized controlled trials, comparative cohorts, long-term follow-up studies, registries, and mechanistic investigations addressing OSA therapies beyond CPAP. Evidence spanning oral appliances, upper-airway and skeletal surgery, hypoglossal nerve stimulation, neuromuscular electrical stimulation, positional therapy, and pharmacologic interventions targeting metabolic and non-anatomical endotypes was integrated. Outcomes of interest included apnea–hypopnea index (AHI), oxygenation, blood pressure, patient-reported symptoms, durability, safety, and real-world adherence. Results: Mandibular advancement devices (MADs) consistently reduced AHI relative to placebo and produced symptom relief comparable to CPAP in mild-to-moderate OSA, largely due to superior adherence. Palatal surgery yielded meaningful short-term improvement in selected patients but demonstrated limited long-term durability. In contrast, maxillomandibular advancement (MMA) achieved the largest and most durable reductions in OSA severity, with efficacy comparable to CPAP and superior to other surgical modalities in appropriate skeletal phenotypes. Hypoglossal nerve stimulation (HNS) produced substantial, durable improvements in AHI and symptoms with high adherence, supported by randomized trials, long-term follow-up, and real-world registry data; newer bilateral and proximal stimulation systems may further broaden candidacy. Neuromuscular electrical stimulation and positional therapy provided modest, phenotype-dependent benefits, primarily as adjunctive or early-stage interventions. A major advance is the emergence of metabolic and endotype-targeted pharmacotherapy: longitudinal data demonstrate a dose-dependent relationship between weight change and OSA progression or regression, while randomized trials show that GLP-1-based therapies—particularly dual GLP-1/GIP agonism with tirzepatide—produce large, clinically meaningful reductions in AHI and cardiometabolic risk in obesity-associated OSA. Additional pharmacologic strategies targeting ventilatory loop gain and arousal threshold further support an endotype-driven treatment paradigm. Conclusions: Contemporary OSA management is shifting from a CPAP-centric model toward a precision-guided, multimodal framework that aligns therapy with dominant anatomic and physiological contributors to airway collapse. Integrating metabolic, neuromodulatory, and structural interventions—often in combination—offers the potential for durable disease control and improved patient-centered outcomes. Future priorities include head-to-head and combination trials, long-term cardiovascular outcomes, cost-effectiveness analyses, and pragmatic tools to operationalize personalized OSA therapy in routine clinical practice. Full article

The optimization of agrochemical spraying can be approached by increasing the efficiency of product distribution, which improves application quality and the biological effectiveness of the treatment. This study presents the development and evaluation of four distinct control strategies to adjust the hydraulic system of a new small, low-cost, electric, vertical variable-rate sprayer based on variations in travel speed, aiming to maintain a constant spray volume during operation and, thereby, increase distribution efficiency. The evaluated algorithms were developed from a mathematical model of the prototype’s hydraulic system obtained from experimental data and using the system identification tool in MATLAB software version 2021. Two open-loop algorithms (linear regression and Fuzzy) and two closed-loop algorithms (Integral and Fuzzy-PD with output integration) were developed. The evaluation was conducted through simulations, using a normalized speed data series provided by the United States Environmental Protection Agency. Performance evaluation results determined that the Fuzzy-PD algorithm with output integration showed the best performance (ISE = 0.21 × 10⁻⁵), followed by the linear regression algorithm (ISE = 3.38 × 10⁻⁵). The results demonstrated that, compared to applications based on fixed rates defined by nominal parameters, the developed sprayer showed potential to improve the uniformity of spray distribution in the field. Full article

A low-temperature tempering staged drying process was proposed in this study to minimize quality degradation and improve drying efficiency during waxy corn drying. Experiments of continuous drying, low-temperature tempering drying, and low-temperature tempering staged drying were conducted to investigate the drying characteristics and quality of waxy corn. The results showed that the low-temperature tempering drying process could shorten the effective drying time and increase the drying rate during the latter stage of the drying process. Under the same hot air temperature, increasing the tempering temperature from 30 °C to 40 °C reduced the effective drying time by 20 min. The Modified Henderson and Pabis model exhibited the best fit to the experimental drying data (R² ≥ 0.9864). The microstructural images of the waxy corn flour showed no significant changes among the experimental groups. The color difference (ΔE) of the continuous drying group was higher than that of the other experimental groups. Both the low-temperature tempering drying process and the low-temperature tempering staged drying process caused less damage to the waxy corn with a relatively lower crack ratio, thereby leading to a reduced electrical conductivity value. The starch content of the 80 °C–60 °C–40 °C group was higher than that of the other experimental groups. Based on comprehensive evaluation of the drying characteristics, the color parameters, and the quality of the dried waxy corn, the 80 °C–60 °C–40 °C group represents a favorable alternative. Full article

Natural gas represents a pivotal transitional clean energy resource, and biogenic coalbed methane (CBM) is ubiquitously distributed in coal reservoirs worldwide. In the context of carbon neutrality targets and the growing demand for large-scale commercial CBM exploitation, innovative technological solutions are urgently required. CBM bioengineering aims to substantially enhance CBM production by stimulating biomethane generation, promoting gas desorption, and improving reservoir permeability, while simultaneously enabling effective CO₂ sequestration. The potential for biomethane generation is largely governed by the intrinsic physicochemical characteristics of coal, including aromatic structures, maceral composition, and pore–fracture architecture. In addition, hydrogeological conditions—such as geothermal gradients, pH variability, and redox potential—play critical roles in regulating microbial functional gene expression and metabolic enzyme synthesis. Core pretreatment strategies in coalbed gas bioengineering can be broadly classified into approaches that enhance coal bioconversion potential and those that optimize functional microbial consortia. Electric fields and conductive materials can influence microbial community structure by enriching electroactive microorganisms and facilitating interspecies electron transfer. In addition to engineered conductive interventions, reservoir environmental conditions also play an important role in shaping methanogenic community structure. Experimental observations under reservoir-relevant CO₂ pressure and temperature conditions indicate that deep coalbed environments are associated with shifts in methanogenic community composition, including an increased relative abundance of hydrogenotrophic methanogens. These observations suggest that physicochemical conditions in deep coal seams may favor hydrogen-dependent CO₂ reduction pathways, thereby supporting hydrogenotrophic methanogenesis and contributing to biomethane generation. The integration of supercritical CO₂ with microbially acclimated stimulation fluids as an innovative reservoir fracturing strategy offers multiple advantages, including effective reservoir stimulation, permanent carbon sequestration, and sustainable biomethane generation. Future research should focus on modulating coal matrix bioavailability, optimizing microbial consortia, enhancing interspecies metabolic synergies, and advancing carbon fixation bioprocesses to facilitate the large-scale implementation of coalbed gas bioengineering systems. This review synthesizes recent advances in microbially mediated CBM enhancement and CO₂ sequestration, with a particular focus on field-scale evidence and the key challenges that must be addressed for large-scale implementation. Full article