Low Oxidation Research Articles

Comparison of Airway Inflammation Characteristics Detected by Lower Exhaled Nitric Oxide in Cough Variant Asthma, Non-Asthmatic Eosinophilic Bronchitis, and Classic Asthma

Objective To investigate the inflammatory profiles of non-asthmatic eosinophilic bronchitis (NAEB), cough variant asthma (CVA), and classic asthma (CA) using fractional exhaled nitric oxide (FeNO) analysis to identify their unique inflammatory phenotypes. Methods This study involved cough patients newly diagnosed, corticosteroid-naïve with CVA (n = 68), NAEB (n = 53), and CA (n = 49). FeNO measurements at exhalation flow rates of 50 mL/s (FeNO50) and 200 mL/s (FeNO200) were conducted. The concentration of alveolar nitric oxide (CaNO) was calculated using a two-compartment model. Inflammatory mediators in induced sputum were also analyzed across the groups. Results Significant differences in FeNO50, FeNO200, and CaNO levels were observed among the three groups (all P < 0.001). Compared to NAEB, CVA patients demonstrated significantly higher FeNO50 levels (27.5 [interquartile range, IQR: 12.0 - 33.0] ppb vs. 16.0 [IQR: 12.5 - 22.0] ppb; P = 0.008) but lower CaNO levels (2.6 [IQR: 1.0 - 4.3] ppb vs. 3.7 [IQR: 2.3 - 6.1] ppb; P = 0.009). CA exhibited the highest levels of FeNO50, FeNO200, and CaNO compared to both NAEB and CVA (all P < 0.01). In CVA, FeNO50 positively correlated with sputum eosinophils, IL-4, and LTC4, whereas NAEB showed elevated CaNO levels with higher sputum eosinophils, IL-5, and PGE2 (all P < 0.05). Conclusions Inflammation predominantly affects the central airways in CVA and the peripheral airways in NAEB, with a more uniform distribution across the airway in CA. These discrepancies in airway inflammation may suggest distinct cough mechanisms in CVA, NAEB, and CA.

Salmonella-induced SIRT1 and SIRT3 are crucial for maintaining the metabolic switch in bacteria and host for successful pathogenesis

Sirtuins are the major players in host immunometabolic regulation. However, the role of sirtuins in the modulation of the immune metabolism pertaining to salmonellosis is largely unknown. Here, our investigation focussed on the role of two important sirtuins, SIRT1 and SIRT3, shedding light on their impact on intracellular Salmonella’s metabolic switch and pathogenesis establishment. Our study indicated the ability of the live Salmonella Typhimurium to differentially regulate the levels of SIRT1 and SIRT3 for maintaining the high glycolytic metabolism and low fatty acid metabolism in Salmonella. Perturbing SIRT1 or SIRT3 through knockdown or inhibition resulted in a remarkable shift in the host metabolism to low fatty acid oxidation and high glycolysis. This switch led to decreased proliferation of Salmonella in the macrophages. Further, Salmonella-induced higher levels of SIRT1 and SIRT3 led to a skewed polarization state of the macrophages from a pro-inflammatory M1 state toward an immunosuppressive M2, making it more conducive for the intracellular life of Salmonella. Alongside, governing immunological functions by modulating p65 NF-κB acetylation, SIRT1, and SIRT3 also skew Salmonella-induced host metabolic switch by regulating the acetylation status of HIF-1α and PDHA1. Interestingly, though knockdown of SIRT1/3 attenuated Salmonella proliferation in macrophages, in in vivo mice model of infection, inhibition or knockdown of SIRT1/3 led to more dissemination and higher organ burden, which can be attributed to enhanced ROS and IL-6 production. Our study hence reports for the first time that Salmonella modulates SIRT1/3 levels to maintain its own metabolism for successful pathogenesis.

A Tetrahydropyran‐Based Weakly Solvating Electrolyte for Low‐Temperature and High‐Voltage Lithium Metal Batteries

AbstractEther‐based electrolytes show great potential in low‐temperature lithium metal batteries (LMBs) for their low viscosity and decent reduction stability. However, conventional ethers with multidentate chelate sites suffer from low oxidation stability and high desolvation energy barrier due to the strong coordination between oxygen and Li+. Herein, cyclic tetrahydropyran (THP) with a unidentate site is designed as a solvent, and fluoroethylene carbonate (FEC) and lithium nitrate (LiNO3) serve as additives for low‐temperature LMBs. The cyclic strain and unidentate chelate effect endow THP with a weak affinity to Li+ ions, which accelerates Li+ desolvation process and induces the anion‐derived electrode/electrolyte interface at low temperature. The formed inorganic‐rich interface further improves the oxidation stability and expedites the interfacial ion transportation. As a result, the assembled Li‐LiNi0.8Mn0.1Co0.1O2 (NMC811) cell stably cycles with 87% capacity retention after 100 cycles at −40 °C and 4.5 V. The 2.7 Ah Li‐NMC811 pouch cell with an energy density of 403 Wh kg−1 delivers 53% of the room‐temperature capacity at −50 °C. This work reveals that regulating the chelate site of solvents can well optimize the electrolytes to realize low‐temperature LMBs.

Development of Lubricants Using Re-Refined Base Stocks—An Effort toward Circular Economy

&lt;div&gt;Re-refining of used lubricating oil is an economically attractive and effective recycling method that contributes significantly to resource conservation and environmental protection. The effective re-refining process of used lubricating oil undergoes thorough purification to remove contaminants and to produce high yield and good quality base oil suitable for reuse in lubricant formulation. Used lubricating oils have various hazardous materials, these can be processed with safe and efficient methods required to recover high-quality base oil products. Typically, used lubricating oil is a mixture of various types of additives, base oils, and viscometric grades as per the different types automotive and industrial applications. Re-refined base oils can be re-used to produce lubricants such as industrial and automotive lubricants like passenger car motor oils, transmission fluids, hydraulic oils, and gear oils. API classified base oils into two categories namely mineral base oils API Group I–III and synthetic base oils Group IV–V. Re-refined base oils meeting API Group I and II quality standards are mostly produced by re-refiners.&lt;/div&gt; &lt;div&gt;In this article, the author has evaluated lubricating oils: gear oil meeting API GL4 specifications based on 25% re-refined base oil to assess the performance of these lubricants in comparison to conventional base oil-based lubricants. This study includes physicochemical tests, lab performance tests (rust, corrosion, shear stability, and oxidation), and tribological performance tests, i.e., weld load, wear scar diameter, and friction performance by MTM was also evaluated. Test results show similar performance in terms of low temperature, oxidation, and friction performance in 25% re-refined base oil-based lubricant with respect to conventional base oil-based products.&lt;figure&gt; &lt;div&gt;&lt;img/&gt;&lt;/div&gt; &lt;/figure&gt; &lt;/div&gt;

Phosphate and two-stage cooking: Impact on lipid oxidation and tenderness in sous-vide beef semitendinosus.

The study investigated phosphate's effects on tenderness and lipid oxidation in beef cooked sous-vide. Semitendinosus beef cuts were treated with 0.15% and 0.3% sodium tripolyphosphate (STPP), and plain water (0% STPP). These cuts were then sous-vide cooked at two different temperatures, 60 °C and 70 °C, for two different durations, 3 h and 6 h. Analytical techniques including Warner-Bratzler shear force (WBSF), pH, thiobarbituric acid reactive substances (TBARS), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR) were employed. STPP concentration did not yield a statistically significant impact on the pH and FTIR spectrum of sous-vide beef (p > 0.05). However, STPP markedly enhanced tenderness by loosening the myofibril structure (observed in SEM) and weakening myosin and actin bands (observed in SDS-PAGE). This improvement led to lower WBSF values with 0.3% STPP, particularly noticeable at 60 °C for 6 h. Additionally, 0.3% STPP delayed lipid oxidation, evidenced by lower oxidation values after 4 weeks of refrigerated storage at 4 °C. These findings highlight STPP's potential to improve tenderness and lipid oxidation stability in sous-vide beef.

Artificial Gold Enzymes Using a Genetically Encoded Thiophenol‐Based Noble‐Metal‐Binding Ligand

Incorporating noble metals in artificial metalloenzymes (ArMs) is challenging due to the lack of suitable soft coordinating ligands among natural amino acids. We present a new class of ArMs featuring a genetically encoded noble‐metal‐binding site based on a non‐canonical thiophenol‐based amino acid, 4‐mercaptophenylalanine (pSHF), incorporated in the transcriptional regulator LmrR via stop codon suppression. We demonstrate that pSHF is an excellent ligand for noble metals in their low oxidation states. The corresponding gold(I) enzyme was characterised by mass spectrometry, UV‐vis spectroscopy and X‐ray crystallography and successfully catalysed hydroamination reactions of 2‐ethynyl anilines with over 50 turnover numbers. Interestingly, two equivalents of gold(I) per protein dimer proved to be required for activity. Up to 98% regioselectivity in the hydroamination of an ethynylphenylurea substrate was obtained, yielding the corresponding phenyl‐dihydroquinazolinone product, consistent with a π‐activation mechanism by single gold centres. The ArM was optimized by site saturation mutagenesis, using an on‐bead screening protocol. This resulted in a single mutant that showed higher activity on one class of substrates. This work brings the power of noble‐metal catalysis into the realm of enzyme engineering and establishes thiophenols as alternative ligands for noble metals, providing new opportunities in coordination chemistry and catalysis.

A recyclable, toughening, extreme-condition resistant flame retardant for unsaturated polyester: Bridging performance and sustainability

Recycling thermosets presents significant economic benefits and social implications, and to date, a series of controllable recycling strategies have been proposed. However, prior research has primarily focused on neat polymers, neglecting the impact of the recycling process on composites whose additives may lose performance post-recycling. The paradigm shift towards sustainability necessitates the development of additives that not only exhibit high performance but also endure recycling conditions. Herein, taking flame-retardant unsaturated polyester (FRUP) as an example, we designed a new flame retardant (DPPONSi) with multiple flame-retardant elements and a low phosphorous oxidation state. FRUP with 16.7 wt% of DPPONSi achieves a V-0 rating in the UL-94 vertical burning test, and its limiting oxygen index (LOI) reaches 27.1%. Moreover, its peak heat release rate and total heat release are distinctively reduced by 65% and 42%, respectively. The high flame-retardant efficiency structure also protected DPPONSi from by-reactions. Without complex separation processes, FRUP degradation products were integrated with polyvinyl alcohol (PVA) to create flame-retardant aerogels with high flame retardancy. Additionally, we systematically studied the influence of flame retardants with varying oxidation states on FRUP, the corresponding flame-retardant mechanisms, and the degradation process of FRUP. This work realizes the organic combination of strategies to enhance the high efficiency of flame retardants with design methods for flame retardants that are resistant to existing unsaturated polyester degradation systems.

Integrated inactivation of Microcystis aeruginosa and degradation of microcystin-LR by direct current glow discharge plasma in liquid-phase: Mechanisms and cell deactivation process

The frequent occurrence of blooms of Microcystis aeruginosa (M. aeruginosa) and the subsequent release of microcystin-LR (MC-LR) in eutrophic waters pose a serious threat to aquatic ecosystems. This study investigated the optimal conditions for inactivating M. aeruginosa and the degrading MC-LR using direct current glow discharge plasma in liquid phase (DC-LGDP), analyzed the potential inactivation mechanisms and the cell deactivation process of M. aeruginosa. The results showed that DC-LGDP generated reactive species (i.e., •OH, 1O2, and H2O2), active Cl and electroporation effect collectively contributed to inactivation of M. aeruginosa and degradation of MC-LR. The 97.07% inactivation efficiency of M. aeruginosa and 94.98% degradation rate of MC-LR were achieved with higher energy yield and without generating nitrogen oxides. Meanwhile, DC-LGDP destroyed the cell integrity, eliminated their antioxidant capacity and reduced the content of photosynthetic pigments. The transcriptome analysis indicated that the transcripts of genes related to photosynthesis, ribosome biosynthesis, ABC transporters, and nitrogen metabolism pathway in M. aeruginosa were altered by DC-LGDP. This study provides insights into the inactivation of M. aeruginosa by DC-LGDP, while elucidating the potential inactivation mechanisms and the cell deactivation process involved. It may be important for the eco-friendly inactivation of M. aeruginosa blooms in natural water bodies. Environmental implicationsThe frequent occurrence of blooms of M. aeruginosa and the subsequent release of MC-LR in eutrophic waters are a global issue. Although glow discharge plasma technologies have been applied for the inactivation of M. aeruginosa, limitations such as low energy yield and additional nitrous oxide production remain. This study aims to explore the optimal conditions for inactivating M. aeruginosa and degrading MC-LR using direct current glow discharge plasma in liquid phase (DC-LGDP), as well as to analyze the inactivation mechanisms and the cell deactivation process of M. aeruginosa. Our results show that the 97.07% inactivation efficiency of M. aeruginosa by DC-LGDP is achieved at higher energy yield and without the generation of nitrogen oxides. The inactivation of M. aeruginosa and degradation of MC-LR are involved in the reactive species generated by DC-LGDP and electroporation effect. These factors induce oxidative stress damaging the cell integrity, impairing the photosynthesis and ribosome biosynthesis pathways of M. aeruginosa, ultimately leading to the cell deactivation of M. aeruginosa. Our findings provide insights into the effective inactivation of M. aeruginosa and the degradation of MC-LR by DC-LGDP with lower energy consumption and environmental friendliness. Thus, it may be important for the inactivation of M. aeruginosa blooms in natural water bodies.

Hydrophobic/hydrophilic surfaces constructed using laser spraying: A new route

Hydrophobic/hydrophilic coatings are widely applied in healthcare, construction, and electronic devices. However, low-cost preparation of coatings is a challenge because they are often associated with complex procedures and adverse environmental impacts. Therefore, an innovative low-cost and environmentally friendly laser spraying technology was employed to fabricate hydrophobic and hydrophilic Ni coatings. The wettability of the coatings was regulated by systematically varying laser power and substrate temperature. The Ni particles presented spherical morphology, low oxidation rate and low coverage rate (4%) with a laser power of 3000 W and room temperature substrate, yielding a hydrophobic coating with a water contact angle of 125.9±17.2°. Conversely, Ni particles exhibited oblate spherical morphology, higher oxidation rate, higher coverage rate (95%) and a porous structure with a laser power of 5400 W and a substrate temperature of 700°C, resulting in a hydrophilic coating with a water contact angle of 8.4±1.2°. These findings demonstrate a novel approach for tailoring the wettability of the Ni coatings, offering new insights into the fabrication of functional coatings for various applications.

Enantio-Recognition and Charge Transfer Complex Formation Involving Tetrathiafulvalene-Appended Chiral 1,2-Cyclohexane-Diamine: An Integrated Experimental and Theoretical Study.

In this work, we exploit the electronic features of tetrathiafulvalene (TTF) as a backbone in synthesizing chiral derivatives. The aim is to make use of TTF's well-known and unique redox and semiconducting properties in the fields of enantio-selective recognition and chiral charge transfer (CT) complex preparation, with the ultimate objective of obtaining devices with various potential applications, ranging from plasmonics to quantum computing. In particular, both cyclohexane-bis (TTF-amide)-based enantiomers 1-(S,S) and 1-(R,R), stable under an oxidation regime, have been selected, and under these conditions, the electrochemical enantiospecific response of the four possible systems, coming from the combination with L- and D-tartaric acid, respectively, was tested. The 1:tartaric acid adducts show lower oxidation potentials than the pristine 1, together with clear enantio-discrimination demonstrated by sizeable potential differences in the range of 29-46 mV between the diastereomeric adducts. Because the oxidation potential of 1 suggests the possibility of the formation of CT complexes, impedance and FT-IR spectra were recorded to confirm this hypothesis in the case of the CT complex 1:I2. The experimental results obtained through the FT-IR analysis were also compared with the theoretical results deriving from the DFT-based calculations.

Physical and Mechanical Properties of Mortar Mixed with Paper Mill Waste

The industrial and construction sectors are experiencing continuous growth each year. Concrete, which is used as the main material in construction, is composed of cement, aggregate and water. Research on mortar and aggregate is carried out to create concrete according to the required specifications of certain buildings. However, 8% of global carbon dioxide emissions come from the cement manufacturing process which is one of the main materials in mortar. In the industrial sector, the paper industry is one of the top producers of waste, approximately 48 tonnes for every 100 tonnes of pulp produced. The main wastes of this industry include slaker grits, dregs, lime mud and fly ash which only end up in landfill. To address this problem, this research investigates the modification of mortar mix materials by utilising paper mill waste. Specifically, fly ash and grits are used as substitute for cement and fine aggregate, respectively. Results indicate that the density value of concrete decreased with the increase of fly ash mixture, and the compressive strength value of mortar with varying additions of 0%, 10%, 20%, 30%, 40% and 50% fly ash reached 7.42, 6.68, 6.18, 4.97, 3.93 and 2.97 MPa. The decrease in density and compressive strength with increasing fly ash content can be attributed to the lower adhesive power of waste compared to cement owing to its lower lime oxide content. The value of compressive strength samples 1, 2 and 3 belong to the N type, which can be used as load-bearing walls, while samples 4, 5 and 6 fall into the O type, which can be used as non-load-bearing and decorative walls in accordance with SNI 03-6882-2014 standards.

Role of plasma neuropeptide Y in acute myocardial infarction: a case-control study

BackgroundAs neuropeptide Y is associated with endothelial dysfunction, this study explored the relationship between neuropeptide Y and acute myocardial infarction.MethodsWe included 128 acute myocardial infarction cases and 62 controls. Using the SYNTAX scoring system, the acute myocardial infarction group was sub-grouped into “SYNTAX ≤ 22,” “SYNTAX = 23–32,” and “SYNTAX ≥ 33.” Plasma neuropeptide Y, endothelin, endothelial nitric oxide synthase, and thromboxane A2 levels were measured.ResultsThe acute myocardial infarction group had higher plasma neuropeptide Y, endothelin, and thromboxane A2 levels than controls ([58.76 ± 17.63 vs. 37.48 ± 11.36 ng/ml, P = 0.000], [36.16 ± 10.04 vs. 27.80 ± 7.18 pg/ml, P = 0.000], and [27.69 ± 6.91 vs. 24.32 ± 7.28 pg/ml, P = 0.002], respectively). The acute myocardial infarction group also had lower plasma endothelial nitric oxide synthase levels than controls (3.00 ± 0.94 vs. 4.05 ± 1.44 ng/ml, P = 0.000). Additionally, the receiver operating characteristic curve analysis showed that a neuropeptide Y value of 49.94 ng/ml could help diagnose acute myocardial infarction (sensitivity: 70.9%; specificity: 91.9%). The SYNTAX scores, smoking, plasma endothelin, thromboxane A2, and neuropeptide Y levels were positively correlated, whereas plasma endothelial nitric oxide synthase and neuropeptide Y levels were negatively correlated. Lastly, plasma neuropeptide Y levels were different among subgroups (P < 0.05); patients with higher SYNTAX scores had higher neuropeptide Y levels.ConclusionsThe levels of plasma NPY may be accociated with the AMI process.

Al@Al2O3 core-shell plasmonic design for the dilemma between high responsivity and low dark current of MoS2 photodetector

The localized surface plasmon resonance (LSPR) effect induced by metal nanoparticles (NPs) can solve the problem of low light absorption in two-dimensional (2D) materials limited by atomic scale. However, the accompanying problem is the rise in dark current due to plenty of electrons from metal NPs injecting into the 2D materials, which decreases the performance of plasmonic photodetectors. Here, we designed the structure of Al NPs coated with Al2O3 by low temperature oxidation treatment method to balance the dilemma between high photoresponse and low dark current. Raman spectrum and finite-difference time-domain simulations were used to verify that Al2O3 does not affect the LSPR effect of Al NPs. Compared to that of the pristine MoS2/Al photodetector, the MoS2/Al@Al2O3 plasmonic photodetector achieved a fourfold decrease in dark current, threefold increase in detectivity, and 1.5-fold increase in responsivity. As a result, the optimized plasmonic device achieves a high responsivity of ∼1719 A/W, an excellent detectivity of ∼6.0 × 1011 Jones, and an ultra-fast response speed of ∼15 ns. Our work reveals that constructing metal NPs covered by ultra-thin oxide layer is a feasible strategy for plasmonic photodetectors to decrease dark current and achieve high performance index.

Oxidation protection efficiency of the combination of Minthostachys mollis K. and Origanum vulgare L. essential oils with "chain-breaking" and "termination-enhancing" antioxidant mechanisms.

The use of antioxidants is known to reduce lipid oxidation. This study aimed to assess the interaction of two antioxidant mechanisms, namely, "chain-breaking" and "termination-enhancing" by combining natural antioxidants derived from "oregano" (Origanum vulgare L.) and "peperina" (Minthostachys mollis K.) essential oils (EOs) in an accelerated oxidation process of sunflower oil at 60°C. Concentrations of 0.05% w/w (1) and 0.02% w/w (2) of the combined oregano and peperina EOs were evaluated. Chemical and volatile oxidation markers were determined in comparison with the pure compounds, an antioxidant-free control, and a BHT-treated sample (0.02% w/w). Although the combinations exhibited lower oxidation indicator values (Anisidine≈136) compared to the control (Anisidine≈213), no evidence of a synergistic effect was observed (Anisidine: Oregano 1≈52; Oregano 2≈199; Peperina 1≈155; Peperina 2≈153), indicating that the combination did not enhance their antioxidant activity beyond that of the pure EOs. Thus, evaluating these combinations in other food matrices is important. PRACTICAL APPLICATION: Food oxidation is one of the main causes of food spoilage, and the search for natural antioxidants has become a necessity for society's increasing food knowledge and consumption preference. The research is focused on demonstrating that not only natural phenolic compounds with a "chain-breaking" mechanism have efficient antioxidant activity but also non-phenolic terpenes using the "termination enhancer" mechanism are efficient, but also the combination of them, which provides more alternative antioxidants for industrial applications.

Mechanism evaluation of edge-water invasion mitigation by low temperature oxidation (LTO) coking in VHSD heavy oil reservoirs: A comparative study with traditional plugging techniques

Heavy oil is one of the globally important unconventional oil and gas resources, and its development faces the challenge of water invasion. The numerical model of a heavy oil reservoir with edge water is established and validated by field data and physical experiments. An evaluation model for selecting water invasion mitigation measures for different targets is established. The mechanisms of mitigating water invasion in the vertical-horizontal well steam drive (VHSD) heavy oil reservoir by cold-water injection, gel injection, nitrogen injection, and “Air + LTO” coking are investigated. The advantages of the “Air + LTO” coking technology in mitigating water invasion are elucidated. The importance of LTO reaction for water invasion mitigation is emphasized. The results show: (1) the edge water flows into the reservoir along the drainage interface of the steam chamber first and forms large water invasion channels in the heated crude oil region in the middle part of the reservoir; (2) the cold-water injection reduces the oil recovery factor by 3 %, the nitrogen injection increases it by 16.3 %, the gel injection improves it by 11.5 % and the “Air + LTO” coking technology enhances it by 24.1 %; (3) after air injection, the coke deposition effectively plugs the water invasion channels in the middle of the reservoir. This research provides a new perspective for mitigating water invasion and improving the oil recovery factor in heavy oil reservoirs with edge water, demonstrating the potential value and feasibility of the “Air + LTO” coking technology.

A conceptual model explaining spatial variation in soil nitrous oxide emissions in agricultural fields

Soil emissions of nitrous oxide contribute substantially to global warming from agriculture. Spatiotemporal variation in nitrous oxide emissions within agricultural fields leads to uncertainty in the benefits of climate-smart agricultural practices. Here, we present a conceptual model explaining spatial variation in temporal patterns of soil nitrous oxide emissions developed from high spatial resolution measurements of soil nitrous oxide emissions, gross nitrous oxide fluxes, and soil physicochemical properties in two maize fields in Illinois, USA. In sub-field locations with consistently low nitrous oxide emissions, soil nitrate and dissolved organic carbon constrained nitrous oxide production irrespective of changes in soil moisture. In sub-field locations where high emissions occurred episodically, soil nitrate and dissolved organic carbon availability were higher, and increases in soil moisture stimulated nitrous oxide production. These findings form the ‘cannon model’ which conceptualizes how sub-field scale variation in soil nitrate and dissolved organic carbon determines where increases in soil moisture can trigger high soil nitrous oxide emissions within agricultural fields.

Comparative study on combustion and emission characteristics of methanol/gasoline blend fueled DISI engine under different stratified lean burn modes

Combining stratified lean-burn techniques with methanol offers a promising path to achieving high efficiency and low emissions in direct-injection spark-ignition (DISI) engines. This work compares the stratified and homogeneous-stratified lean-burn characteristics of methanol/gasoline fuels on a DISI engine. Combustion and emissions characteristics under two stratified lean-burn strategies were investigated. The results indicate that compared to double-injection stratified lean-burn (DISL), single-injection stratified lean-burn (SISL) leads to more timely combustion, which deteriorates more slowly as the excess air ratio increases. Using M20 fuel with SISL achieves a higher tolerance for air dilution. At the same excess air ratio, SISL results in higher maximum in-cylinder pressure and combustion temperature, but lower exhaust temperature. The economic zone for SISL occurs with M40 fuel at λ = 1.3–1.6, whereas DISL's economic zone is within λ = 1.1–1.3. When λ is below 1.5, SISL produces higher hydrocarbon (HC) emissions but lower nitrogen oxides (NOx) emissions. However, as λ exceeds 1.5, HC emissions from DISL increase sharply while NOx emissions decrease significantly. The particle concentration from SISL is at least an order of magnitude higher than that from DISL, with particle size distribution forming a unimodal curve centered around accumulation mode particles. Conversely, DISL exhibits a quasi-bimodal distribution.

Laser Cutting of Non-Woven Fabric Using UV Nanosecond Pulsed Laser.

The efficient cutting of non-woven fabric shows great significance to the development of the textile industry. In recent years, laser cutting technology has been widely applied in the clothing industry due to its high efficiency and cutting quality. In this work, a UV nanosecond pulsed laser with a wavelength of 355 nm and a max power of 6.5 W is used to cut non-woven fabric with a thickness of 0.15 mm. The variation of kerf width, surface morphology, and chemical contents are investigated under different laser processing parameters, and the optimal processing parameter is determined. The experimental results demonstrate that the degree of crystallization and chemical composition of the kerf on the non-woven fabric surface is significantly influenced by laser cutting parameters such as laser scanning speed (from 100 to 700 mm/s) and frequency (from 20 to 70 kHz). The scanning speed of 500 mm/s and frequency of 30 kHz are considered the best parameters for achieving abundant energy for the complete and efficient cutting of non-woven fabric. In addition, the level of carbonization and oxidation reaches a relatively low value, and the kerf width is 0.214 mm, which is considered a reasonable value under the optimal processing parameters, showing high cutting quality. Furthermore, the effect of different cutting treatments on surface morphology and chemical contents is also studied. The experimental results present that the non-woven fabric cut by laser possesses a flat kerf, showing a similar effect to that of scissor cutting. Moreover, due to the programmability of laser processing patterns, it is possible to create more intricate designs on non-woven fabric. This facilitates the application and promotion of laser-cut non-woven fabrics. These results can provide a certain reference for laser cutting in the textile industry and are expected to allow for the cutting of high-quality kerf with low carbonization and oxidation.

Enhanced ablation resistance and mechanical behavior of spark plasma sintered ZrB2-SiC composites with TiC addition

The study evaluated the ablation resistance and mechanical behavior of spark plasma sintered ZrB2-25 vol% SiC-TiC (5–15 vol%) composites. The addition of TiC improved ablation resistance by promoting the formation of ZrO2.TiO2 and TiO2 phases on the oxidized composites. The ZrB2-25 vol% SiC-15 vol% TiC composite exhibited the lowest mass ablation rate of 0.11 mg/s and maximum fracture toughness of 5.8±0.29 MPa.m0.5. After ablation, SiC particle pull-out, crack deflection and crack bridging were identified as the primary toughening mechanisms. The maximum microhardness of 23.01±1.18 GPa and compressive strength of 1688.2±75.5 MPa were obtained for the ZrB2-25 vol% SiC-10 vol% TiC composite, which correspond to 92.86 % and 94.31 % of their respective maximum values prior to ablation. Furthermore, nanoindentation studies revealed significant improvements in both elastic modulus and nanohardness with the addition of TiC due to reduction in porosity and refinement in SiC grain size. After ablation, the elastic modulus and nanohardness reduced. However, the ZrB2-25 vol% SiC-10 vol% TiC composite retained a maximum elastic modulus of 433.61 GPa and nano-hardness of 21.88 GPa. The oxidation behavior of ZrB2-SiC composites containing TiC was analyzed at 1500°C for 6 hours in air. The TiC-containing composite exhibited lower mass gain, lower parabolic oxidation rate constant and a thin oxide layer compared to the ZrB2-SiC composites.

Isomeric chlorination of conjugated thiophene side chain based on quinoxaline to design high-performance electrochromic polymers

The isomeric chlorination of the conjugated side chain is an effective method to improve the photoelectronic properties of polymers, but has not been well investigated in electrochromic performance. Herein, two new D-A-D type isomeric monomers, EQx-α-Cl and EQx-β-Cl, based on 2,3-bis(5-chloro-4-(2-ethylhexyl)thioph-en-2-yl)-6,7-difluoro-5,8-di(thiophen-2-yl)quinoxaline (Qx-α-Cl) and 2,3-bis(4-chloro-5-(2-ethylhexyl)thiophen-2-yl)-6,7-difluoro-5,8-di(thiophen-2-yl)quinoxaline (Qx-β-Cl) as the acceptor units by the isomeric chlorination of the different position of the conjugated thiophene side chain were designed and synthesized. Then their D-A-D type polymers (PEQx-α-Cl and PEQx-β-Cl) were synthesized by electrochemical polymerization. EQx-α-Cl not only exhibits slight red-shifted absorption onset and much stronger absorption with molar extinction coefficient of 1.16 × 105 M−1 cm−1 but also shows lower onset oxidation potential (Eonset) of 0.65 V compared with those of EQx-β-Cl (7.26 × 104 M−1 cm−1 and 0.73 V). And PEQx-α-Cl displayed yellow green at neutral state and dark green at oxidation state, respectively, and showed much better electrochemical stability and electrochromic performance including the higher optical contrast 37.7 % and the CE value of 319 cm2 C−1 at 890 nm in comparison with PEQx-β-Cl, which was beneficial to design the electrochromic materials toward adaptive camouflage application. These results demonstrated that the isomeric chlorination strategy of conjugated side chain is a promising approach which may open up a new horizon for designing and synthesizing the high-performance electrochromic polymers.