Search Results (188)

White-light-emitting diodes (wLEDs) are central to next-generation lighting technologies, yet their reliance on critical raw materials (CRMs), such as rare-earth elements, raises concerns regarding sustainability and supply security. In this work, we present a simple, low-cost method to produce photoluminescent carbon-based nanostructures—known as oxidative debris (OD)—via alkaline treatment of graphene oxide (GO) using KOH solutions ranging from 0.04 M to 1.78 M. The resulting OD, isolated from the supernatant after acid precipitation, exhibits strong and tunable photoluminescence (PL) across the visible spectrum. Emission peaks shift from blue (~440 nm) to green (~500 nm) and yellow (~565 nm) as a function of treatment conditions, with excitation wavelengths between 300 and 390 nm. Optical, morphological. and compositional analyses were performed using UV-Vis, AFM, FTIR, and Raman spectroscopy, confirming the presence of highly oxidized aromatic domains. The blue-emitting (S2) and green/yellow-emitting (R2) fractions were successfully separated and characterized, demonstrating potential color tuning by adjusting KOH concentration and treatment time. This study highlights the feasibility of reusing GO-derived byproducts as sustainable phosphor alternatives in wLEDs, reducing reliance on CRMs and aligning with green chemistry principles. Full article

A continuous increase in artificial intelligence (AI)-based functions can be expected for future aviation systems, posing significant challenges to traditional development processes. Established systems engineering frameworks, such as the V-model, are not adequately addressing the novel challenges associated with AI-based systems. Consequently, the European Union Aviation Safety Agency (EASA) introduced the W-shaped process, an advancement of the V-model, to set a regulatory framework for the novel challenges of AI Engineering. In contrast, the agile Development Operations (DevOps) approach, widely adopted in software development, promotes a never-ending iterative development process. This article proposes a novel concept that integrates aspects of DevOps into the W-shaped process to create an AI Engineering framework suitable for aviation-specific applications. Furthermore, it builds upon proven ideas and methods using AI Engineering efforts from other domains. The proposed extension of the W-shaped process, compatible with ongoing standardizations from the G34/WG-114 Standardization Working Group, a joint effort between EUROCAE and SAE, addresses the need for a rigorous development process for AI-based systems while acknowledging its limitations and potential for future advancements. The proposed framework allows for a re-evaluation of the AI/ML constituent based on operational information, enabling improvements of the system’s capabilities with each iteration. Full article

This study systematically investigated the effects of selective laser melting (SLM) process parameters on the forming quality and microstructure of FeCrAl oxide dispersion-strengthened (ODS) alloy. Through orthogonal experimental design, the influences of laser power (300–320 W), scanning speed (650–850 mm/s), and hatch spacing (0.05–0.07 mm) on the surface morphology and internal defects of as-built samples were analyzed. The microstructural evolution under different volumetric energy densities (VED) was also analyzed. The results indicate that hatch spacing significantly affected crack and pore formation, with minimal defects observed at 0.06 mm. Excessive laser power (320 W) or VED (318.0 J/mm³) led to elevated melt pool temperatures, causing element evaporation, grain coarsening, and <100> preferential oriented texture, thereby reducing hardness to 234 HV. The optimal parameters—laser power of 310 W, scanning speed of 650 mm/s, and hatch spacing of 0.06 mm (VED 265.0 J/mm³)—yielded the highest hardness (293 HV), fine-grained structures, and a high proportion of low-angle grain boundaries (LAGBs) with significant residual stress. This research provides a theoretical foundation for optimizing SLM processes for FeCrAl-ODS alloys. Full article

The biology literature addresses two puzzles: (i) the increase in specific metabolic rate of organs (SOrMR, W/kg of organ) with a decrease in body mass (M_B) of biological species (BS), and (ii) how the organs recognize they are in a smaller or larger body and adjust metabolic rates of the body (${\dot{q}}_B$) accordingly. These puzzles were answered in the author’s earlier work by linking the field of oxygen-deficient combustion (ODC) of fuel particle clouds (FC) in engineering to the field of oxygen-deficient metabolism (ODM) of cell clouds (CC) in biology. The current work extends the ODM hypothesis to predict the whole-body metabolic rates of 114 BS and demonstrates Kleiber’s power law {${\dot{q}}_B = a {M_B}^b$}. The methodology is based on the postulate of Lindstedt and Schaeffer that “150 ton blue whale. and the 2 g Etruscan shrew.. share the same.. biochemical pathways” and involve the following steps: (i) extension of the effectiveness factor relation, expressed in terms of the dimensionless group number G (=Thiele Modulus²), from engineering to the organs of BS, (ii) modification of G as G_OD for the biology literature as a measure of oxygen deficiency (OD), (iii) collection of data on organ and body masses of 116 species and prediction of SOrMR_k of organ k of 114 BS (from 0.0076 kg Shrew to 6650 kg elephant) using only the SOrMR_k and organ masses of two reference species (Shrew, 0.0076 kg: RS-1; Rat Wistar, 0.390 kg: RS-2), (iv) estimation of ${\dot{q}}_B$ for 114 species versus M_B and demonstration of Kleiber’s law with a = 2.962, b = 0.747, and (v) extension of ODM to predict the allometric law for maximal metabolic rate (under exercise, {${\dot{q}}_{B,MMR} = a_{MMR} {M_B}^{b_{MMR}}$}) and validate the approach for MMR by comparing b_MMR with the literature data. A method of detecting hypoxic condition of an organ as a precursor to cancer is suggested for use by medical personnel Full article

The study investigated the effect of osmotic treatment, edible coatings, and reduced pressure on the quality of carrots dried by the microwave–vacuum method (MVD) at 3.5 or 6.5 kPa and microwave power of 250 W. Initial osmotic enrichment (OE) of carrots was carried out in chokeberry NFC juice, and osmotic dehydration (OD) in chokeberry juice concentrate. Coatings were prepared using sodium alginate or citrus pectin solutions of 1.0 or 1.5%. Osmotic treatment, and then drying pressure, had the greatest effect on increasing the dry matter (DM), total phenolic content (TPC), and color changes, but also on decreasing the water activity (AW) of dried carrot. The highest DM (average 98.7%) and the lowest AW (average 0.25) were obtained in OE carrots and dried at 3.5 kPa. Drying carrots, combined with osmotic treatment and coating, increased TPC by 13-fold, from 225 in fresh to 3229 mg GAE/100 g d.m. in dried carrots. Osmotic treatment did not affect the antioxidant activity of DPPH•, but OD significantly increased ABTS•+ compared to the raw material. Coatings had a smaller effect on color changes and antioxidant activity (DPPH• and ABTS•+) and no significant impact on DM and AW. The color changes of the control and coated samples were an increase in color lightness, redness, yellowness, and saturation (vividness), and those subjected to osmotic treatment showed a decrease in these parameters. The lower AW of dried carrots positively affected higher hardness. All samples were sensory accepted, including color, texture, and smell, especially after OD in chokeberry juice concentrate, while crunchiness was the lowest (five out of nine points). Full article

A novel tungsten-based heterojunction nanocomposite material was developed for the efficient oxidative desulfurization (ODS) of fuel oil, enabling the production of low-sulfur fuel and a reduction in harmful SO_x emissions. In this material, the WC/W₂C heterojunction was uniformly immobilized on a porous nitrogen-doped carbon (NC) matrix structure through facile in situ pyrolysis of polyaniline–phosphotungstic acid (PANI/PTA) precursors. The resultant WC/W₂C@NC catalyst demonstrated remarkable desulfurization performance, achieving 100% removal of 4000 ppm dibenzothiophene (DBT) in just 15 min at 60 °C in the presence of 0.03 g of WC/W₂C@NC and a H₂O₂/S molar ratio of 2. This exceptional activity is attributed to the synergistic effects stemming from the accelerated electron transfer by the NC matrix, the intricate porous network, and the abundant WC/W₂C heterojunction active sites. Moreover, the in situ formation of NC around WC/W₂C mitigated active site leaching, ensuring remarkable stability, with a DBT removal rate of 97.2% maintained even after eight recycling cycles. This work provides a versatile and scalable approach for fabricating tungsten-based heterojunction catalysts and highlights the potential of WC/W₂C@NC as a high-performance, durable ODS catalyst, paving the way for further advancements in sustainable desulfurization technologies. Full article

Raman scattering measurements were performed on 1 mol dm⁻³ aqueous calcium nitrate (Ca(NO₃)₂) and sodium nitrate (NaNO₃) solutions containing 4% (w/w) D₂O in a temperature range from 25 to 350 °C and pressure of 40 MPa. As the temperature increased, the N–O symmetric stretching vibrational band (ν₁) of NO₃⁻ at 1045–1047 cm⁻¹ shifted to a lower wavenumber by 5~6 cm⁻¹. The band analysis using one Lorentzian component showed that the full-width at half maximum (FWHM) did not change significantly below 175 °C but increased rapidly above 200 °C for both solutions. The peak area for an aqueous Ca(NO₃)₂ solution showed a breakpoint between 225 and 250 °C, suggesting a change in the coordination shell of NO₃⁻ at 175~250 °C. The OD symmetric stretching vibrational band of HDO water was deconvoluted into two Gaussian components at 2530 and 2645 cm⁻¹; the former component has high temperature dependence that is ascribed to the hydrogen bonds, whereas the latter one shows less temperature dependence due to the non-hydrogen bonds of water. X-ray scattering measurements were performed on a 1 mol dm⁻³ aqueous Ca(NO₃)₂ solution at 25 to 210 °C and 40 MPa. Empirical potential structure refinement (EPSR) modeling was used to analyze the X-ray scattering data. Ca²⁺ forms a rigid coordination shell consisting of about seven water molecules at 2.48 Å and one NO₃⁻ at 25~170 °C, with further water molecules substituted by NO₃⁻ at 210 °C. NO₃⁻ is surrounded by 13~14 water molecules at an N–Ow distance of 3.6~3.7 Å. The tetrahedral network structure of solvent water pertains from 25 to 170 °C but is transformed to a dense packing arrangement at 210 °C. Full article

Laser Powder Bed Fusion (LPBF) enables the efficient production of near-net-shape oxide dispersion-strengthened (ODS) alloys, which possess superior mechanical properties due to oxide nanoparticles (e.g., yttrium oxide, Y-O, and yttrium-titanium oxide, Y-Ti-O) embedded in the alloy matrix. To better understand the precipitation mechanisms of the oxide nanoparticles and predict their size distribution under LPBF conditions, we developed an innovative physics-based multiscale modeling strategy that incorporates multiple computational approaches. These include a finite volume method model (Flow3D) to analyze the temperature field and cooling rate of the melt pool during the LPBF process, a density functional theory model to calculate the binding energy of Y-O particles and the temperature-dependent diffusivities of Y and O in molten 316L stainless steel (SS), and a cluster dynamics model to evaluate the kinetic evolution and size distribution of Y-O nanoparticles in as-fabricated 316L SS ODS alloys. The model-predicted particle sizes exhibit good agreement with experimental measurements across various LPBF process parameters, i.e., laser power (110–220 W) and scanning speed (150–900 mm/s), demonstrating the reliability and predictive power of the modeling approach. The multiscale approach can be used to guide the future design of experimental process parameters to control oxide nanoparticle characteristics in LPBF-manufactured ODS alloys. Additionally, our approach introduces a novel strategy for understanding and modeling the thermodynamics and kinetics of precipitation in high-temperature systems, particularly molten alloys. Full article

Various Keggin-type heteropolyoxometalate catalysts with structural defects and surface acidity were synthesized by immobilizing 12-phosphotungstic acid (HPW) on mesoporous SBA−15, to produce near-zero-sulfur diesel fuel. As the calcination temperature increased, the W=O and the corner-shared W–O–W bonds in the Keggin unit partially broke, creating oxygen defects, as evidenced by the Rietveld refinement and in situ FTIR characterization. All the catalysts contained Lewis (L) and Brønsted (B) acid sites, with L acidity predominant. The relative intensity of the IR band (I₉₈₀) of W=O bond inversely correlated with the number of L acid sites as the calcination temperature varied, suggesting that oxygen defects contributed to the Lewis acid sites formation. In the oxidation of dibenzothiophene (DBT) in a model diesel within a biphasic system, DBT conversion exceeded 99% under the optimal reaction conditions (reaction temperature 70 °C, reaction time 60 min, H₂O₂/sulfur molar ratio 8, H₂O₂/formic acid molar ratio 1.5, catalyst concentration 2 mg/mL). The influence of fuel composition and addition of indole and 4,6-DMDBT on DBT oxidation were also evaluated. Indole and cyclohexene negatively impacted the DBT oxidative removal. Oxygen defects served as active centers for competitive adsorption of sulfur compound and oxidant. Both L and B acid sites were involved in transferring O atom from peroxophosphotungstate complex to sulfur in DBT, resulting in DBTO₂ sulfone, which was immediately extracted by polar acetonitrile. This study confirms that structural defects and surface acidity are crucial in the deep oxidative desulfurization (ODS) reaction, and in enabling the simultaneous oxidation and separation of refractory organosulfur compounds in a highly efficient model diesel. Full article

Bone grafts are commonly used in orthopedic and dental surgeries to facilitate bone repair and regeneration. A new type of bone graft, polycaprolactone-infiltrated three dimensionally printed hydroxyapatite (3DP HA/PCL), was previously developed by infiltrating polycaprolactone (PCL) into preformed three-dimensional-printed hydroxyapatite (3DP HA) that was fabricated using binder jetting technology combined with a low-temperature phase transformation process. However, when producing small granules, which are often used for bone grafting, issues of granule agglomeration emerged, complicating the application of this method. This study aimed to develop a fabrication process for 3DP HA/PCL bone graft granules using solution infiltration and liquid agitation. The effects of varying PCL solution concentrations (40% and 50% w/w) and different agitating liquids (deionized water or DI, N-Methyl-2-Pyrrolidone or NMP, and an NMP-DI mixture) on the properties of the resulting composites were investigated. XRD and FTIR analysis confirmed the coexistence of HA and PCL within the composites. The final PCL content was comparable across all conditions. The contact angles of 3DP HA/PCL were 26.3 and 69.8 degree for 40% and 50% PCL solution, respectively, when using DI, but were zero when using NMP and NMP-DI. The highest compression load resistance and diametral tensile strength were achieved using the 50% PCL solution with DI or the NMP-DI mixture. DI resulted in a dense PCL coating, while NMP and the NMP-DI mixture produced a porous and irregular surface morphology. All samples exhibited a porous internal microstructure due to PCL infiltration into the initial pores of the 3D-printed HA. Biocompatibility tests showed that all samples supported the proliferation of MC3T3-E1 cells, with the greatest OD values observed for the 50% PCL solution with DI or the NMP-DI mixture at each cultured period. Considering the microstructural, mechanical, and biological properties, the 50% PCL solution with the NMP-DI mixture demonstrated overall desirable properties. Full article

Background and Objectives: Sustained virologic responses (SVRs) lead to a decrease in portal hypertension, the regression of fibrosis, and the improvement in the hepatic synthesis of procoagulant and anticoagulant factors. We aimed to assess the influence of SVR on coagulation parameters in cirrhotic patients with HCV treated with DAAs. Methods: We performed a prospective study in the Institute of Gastroenterology and Hepatology Iasi, Romania, between January 2022 and February 2024. We included patients diagnosed with compensated and decompensated HCV-related liver cirrhosis, treated with direct antivirals (PrOD ± RBV or SOF/LED ± RBV) for 12/24 weeks. Blood samples for biochemical, immunological, and coagulation tests were collected at the baseline, end of treatment (EOT), and once sustained virological response had been achieved over a period of 12/24 weeks (SVR12/24). Results: We analyzed a group of 52 patients with HCV-related liver cirrhosis, predominantly female (68.0%), and the degree of severity of cirrhosis placed the patients mainly in Child–Pugh classes B (40%) and C (36%). All patients achieved SVRs. The MELD score decreased at EOT (13.48 ± 4.273; p = 0.001) and SVR (9.88 ± 2.774; p = 0.000), compared to the baseline (14.92 ± 4.707). The FibroScan values decreased at SVR (17.596 ± 3.7276; p = 0.000) compared to the baseline (26.068 ± 7.0954). For all common coagulation parameters (platelets, INR, PT, fibrinogen, aPTT), there was a trend towards improvement during treatment, including changes which were statistically significant for the majority of patients. Factor II was low at the baseline (75.40 ± 7.506) but increased at EOT (87.40 ± 9.587) and, later, at SVR (99.12 ± 11.695; p = 0.000). The FVIII values increased at the baseline (175.52 ± 16.414) and decreased at EOT (151.48 ± 13.703) and SVR (143.40 ± 13.937). The FvW values decreased during treatment (146.84 ± 9.428, at baseline; 141.32 ± 9.690, p = 0.000, at EOT; and 126.68 ± 17.960, at SVR). In regard to the anticoagulant factors (PC, PS, ATIII), a significant improvement was brought on by SVR. Advanced stages of liver disease showed the most diminished FII activity, while at the baseline and in Child–Pugh C patients we recorded the highest values of FVIII and FvW. Conclusions: Our study proved that the “reset” of coagulopathy might be due to the improvement in liver function due to viral eradication secondary to AAD therapy. Full article

Multiform NiO nanowalls with a high specific surface area were constructed in situ on carbon foam (CF) to construct NiO@CF/OD composite phase change materials (CPCMs). The synthesis mechanism, microstructures, thermal management capability, and photothermal conversion of NiO@CF/OD CPCMs were systematically studied. Additionally, the collaborative enhancement effects of CF and multiform NiO nanowalls on the thermal properties of OD PCMs were also investigated. NiO@CF not only maintains the porous 3D network structure of CF, but also effectively prevents the aggregation of NiO nanosheets. The chemical structures of NiO@CF/OD CPCMs were analyzed using XRD and FTIR spectroscopy. When combined with CF and NiO nanosheets, OD has high compatibility with NiO@CF. The thermal conductivity of NiO@CF/OD-L CPCMs was 1.12 W/m·K, which is 366.7% higher than that of OD. The improvement in thermal conductivity of CPCMs was theoretically analyzed according to the Debye model. NiO@CF/OD-L CPCMs have a photothermal conversion efficiency up to 77.6%. This article provided a theoretical basis for the optimal design and performance prediction of thermal storage materials and systems. Full article

This paper concerns control BVPs, driven by ODEs $x^{\prime }\left(t\right)=u\left(t\right)$, using controls $u^0\left(·\right)$ $\&u^1\left(·\right)$ in $L^1\left(\left(a,b\right),{\mathbb{R}}^2\right)$. We ask these two controls to satisfy a very simple restriction: at points where their first coordinates coincide, also their second coordinates must coincide; which allows one to write $(u^1-u^0)\left(·\right)=v\left(·\right)\left(1,f\left(·\right)\right)$ for some $f\left(·\right)$. Given a relaxed non bang-bang solution $\overline{x}\left(·\right)\in W^{1,1}\left(\left[a,b\right],{\mathbb{R}}^2\right)$, a question relevant to applications was first posed three decades ago by A. Cellina: does there exist a bang-bang solution $\widehat{x}\left(·\right)$ having lower first-coordinate ${\widehat{x}}_1\left(·\right)\le {\overline{x}}_1\left(·\right)$? Being the answer always yes in dimension $d=1$, hence without $f\left(·\right)$, as proved by Amar and Cellina, for $d=2$ the problem is to find out which functions $f\left(·\right)$ “are good”, namely “allow such 1-lower bang-bang solution $\widehat{x}\left(·\right)$ to exist”. The aim of this paper is to characterize “goodness of $f\left(·\right)$” geometrically, under “good data”. We do it so well that a simple computational app in a smartphone allows one to easily determine whether an explicitly given $f\left(·\right)$ is good. For example: non-monotonic functions tend to be good; while, on the contrary, strictly monotonic functions are never good. Full article

The objective was to review, using an integrated approach, all parameters related to osmotic dehydration, freezing, and frozen storage when assessing the advantages of the osmodehydrofreezing-ODF process. Peeled cherry tomatoes were treated at (T) 25, 35, and 45 °C (t) up to 180 min in glycerol-based OD-solution (50, 60, 70% w/w). OD was studied and optimized by applying the Response Surface Methodology, combined with selected desirability criteria to define the optimum process parameters. Water loss-WL, solid gain-SG, water activity reduction-a_w, texture and color changes were monitored during the process. Untreated and OD-treated at optimal OD conditions (C = 61.5%, T = 36 °C; t = 72 min) samples were frozen and stored at isothermal (T, −5, −8, −14, −23 °C) and non-isothermal temperature conditions (T_eff, −7.3 °C). OD samples presented acceptable color, increased firmness, low drip loss and high vitamin C/lycopene retention during frozen storage. OD increased the shelf life of frozen cherry tomato (up to 3.5 times based on sensory quality loss). The kinetic models obtained for vitamin and lycopene degradation and sensory quality loss were validated at non-isothermal conditions. Full article

The study involves the use of commercial cellulase Cellic CTec2 in combination with two in-house xylanases, PxXyn10A (XynA), a recombinant purified enzyme from Paenibacillus xylanivorans A59, and a xylanase enzymatic extract from native Moesziomyces aphidis PYCC 5535T (MaPYCC 5535T), for the enzymatic hydrolysis of pretreated blue agave bagasse (BAB) at the high solids load of 20% (w/v). Three different combinations of cellulase and xylanases were evaluated. When Cellic^® CTec2 was used at a dosage of 10 FPU/g oven-dried solids (ODS) supplemented with XynA or MaPYCC 5535T at an endo-xylanase dosage of 100 U/g ODS, increases in the xylose yield of 30% and 33%, respectively, were obtained. When applying in-house xylanases alone (at an endo-xylanase dosage of 100 U/g ODS), xylan in BAB was selectively hydrolyzed into xylose with 5% yield with MaPYCC 5535T, while no xylose was detected with XynA. Interestingly, a synergic effect of Cellic^® CTec 2 with both xylanases was observed when using a low dosage of 1 FPU/g ODS (allowing for some liquefaction of the reaction mixture), promoting xylose and glucose release by either xylanase. A higher concentration of monomeric sugars was obtained with 10 FPU/g ODS of Cellic^® Ctec 2 supplemented with 100 U/g ODS of MaPYCC 5535T, followed by XynA. The improvement in saccharification through the synergistic combination of in-house xylanases and commercial cellulases allows for the obtention of sugar-rich hydrolysates, which enhances the technical sustainability of the process. Hydrolysates were then fermented using recombinant Cellux 4^TM yeast to yield 45 g/L ethanol, representing an increase of about 30% with respect to the control obtained with only the commercial cellulase cocktail. The surface modification of agave biomass with the different combinations of enzymes was evidenced by scanning electron microscopy (SEM). Full article