Numerical study of the plasmonic slab lens for improving direct-write nano lithography.

Plasmonic direct-write lithography (PDWL) provides a potential tool for the fabrication and manufacturing at the nano scale due to its high-resolution and low-cost. However, the shallow exposure depth hinders its practical application. Here, we incorporate the plasmonic slab lenses (PSLs) into PDWL to amplify and compensate evanescent waves, leading to improved light intensity, depth, resolution and better tolerance to the air gap beyond the near field optical lithography. Two typical plasmonic probes with different nanostructure and localized plasmonic resonance mechanisms are designed and fabricated as representatives, the local intensity enhancement of which mainly depend on the oscillations of transverse and longitudinal electric field components, respectively. Optimizations considering the PSL structure, material and the illuminating wavelength are performed to amplify different field components and figure out the best lithography configuration. Simulation results indicate that Ag-Ag cavity PSL and 355 nm illumination is the best combination for the lithography with bowknot aperture probe, while the semi-ring probe exhibits better performance under the condition of Ag-Al cavity PSL and 405 nm illumination. The semi-ring probe in combination with a plasmonic cavity, for instance, is demonstrated to enhance the light intensity by 4 times at the bottom layer of the photoresist compared to that without PSL and realize a lithography resolution of 23 nm. Our scheme is believed to boost the application of PDWL as a high-resolution and low-cost nanofabrication technology, and it may even serve as an alternative for the high-cost scanning method, such as focused ion beam and electron beam lithography.

Improvement in the quality of frozen dough for fried flour products by electrostatic field-assisted freezing.

BACKGROUND: With the development of the food industry, frozen dough technology has gradually become an indispensable part of dough processing but its quality is often reduced due to freezing during the production process. Electrostatic field-assisted freezing (EF) technology, a key research project in recent years, reduces the physical damage to food materials by reducing or changing the size of ice crystals in frozen products. RESULTS: In this study, different intensities of electrostatic fields were used to assist in the repeated freezing and thawing of dough. The effects of electrostatic fields on the freezing nucleation process were evaluated by measuring dough freezing curves, low field nuclear magnetic resonance, and melting enthalpy. It was found that the freezing time of frozen dough added with electrostatic field-assisted freezing processing was shortened, the rate at which hardness, viscosity, and elasticity decreased was reduced, and the indicators of water distribution and protein secondary structure components were closer to those of fresh dough. CONCLUSION: This experiment used electrostatic field-assisted freezing to reduce the damage to the dough structure during the freezing process, improve the quality of frozen dough and fried products, and improve the freezing efficiency of frozen dough. It provides a new idea for the study of frozen dough. © 2023 Society of Chemical Industry.

Insight into humification of mushroom residues under addition of Rich-N sources: Comparing key molecular evolution processes using EEM-PARAFAC and 2D-FTIR-COS analysis.

Accelerating the humification of organic solid waste is one of the most important issues in composting. This present study aims to study and compare the humification process of different rich-N sources (chicken manure, cattle manure, and urea) addition during the composting of mushroom residues, from macro physicochemical properties to micro humic molecular structure evolution process. The physicochemical elements and humic components were determined for evaluating the compost quality and humification degree as composting proceed. The coupled analysis of excitation-emission matrix with parallel factor analysis (EEM-PARAFAC) and two-dimensional correlation with Fourier transform infrared spectrum (2D-FTIR-COS) were used to characterize the functional molecular structure evolution of dissolved organic matter during humification process. The results indicated that the rank order for humification level were the treatments of chicken manure (HM), urea (UM), cattle manure (CM), and single mushroom residue treatment (CK), with their humification index of 22.18%, 22.05%, 18.47%, and 16.52%, respectively. Humic substance, humic acid, and fulvic acid were obtained the highest in HM treatment with contents of 35.41 ± 0.86%, 23.32 ± 1.57%, and 10.97 ± 0.52%, respectively. The rich-N source addition enhanced the degradation of protein-like and polysaccharides-like substances in dissolved organic matter, thus accelerating the humification process of mushroom residues. The key structure evolution of dissolved organic matter in the HM treatment, in which the CO and CC stretching of quinone, amide, or ketone, and the C-O stretching of polysaccharides may be responsible for the faster formation of humus compared to the other nitrogen treatments. In this study, redundancy analysis indicated that the total nitrogen (TN) and nitrate nitrogen (NO3--N) may be the potential indicators for determining the humification level as composting proceed. The result provides significant insight into the humification mechanism of mushroom residue under different types of nitrogen sources at the molecular level, and will be reference for improving the composting technique in practical field.

Dynamics of antibiotic resistance genes and bacterial community during pig manure, kitchen waste, and sewage sludge composting.

Organic solid wastes (OSWs) are important reservoirs for antibiotic resistance genes (ARGs). Aerobic composting transforms OSWs into fertilizers. In this study, we investigated ARGs dynamics and their driving mechanisms in three OSW composts: pig manure (PM), kitchen waste (KC), and sewage sludge (SG). The dominant ARGs were different in each OSW, namely tetracycline, aminoglycoside, and macrolide resistance (PM); tetracyclines and aminoglycosides (KC); and sulfonamides (SG). ARGs abundance decreased in PM (71%) but increased in KC (5.9-fold) and SG (1.3-fold). Interestingly, the ARGs abundance was generally similar in all final composts, which was contributed to the similar bacterial community in final composts. In particular, sulfonamide and ß-lactam resistant genes removed (100%) in PM, while sulfonamide in KC (38-fold) and tetracycline in SG (5-fold) increased the most. Additionally, ARGs abundance rebounded during the maturation period in all treatments. Firmicutes, Proteobacteria, and Actinobacteria were the main ARGs hosts. Several persistent and high-risk genes included tetW, aadA, aadE, tetX, strB, tetA, mefA, intl1, and intl2. The structural equation models showed ARGs removal was mainly affected by physicochemical parameters and bacterial communities in PM, the ARGs enrichment in KC composting correlated with increased mobile genetic elements (MGEs). In general, thermophilic aerobic composting can inhibit the vertical gene transfer (VGT) of pig manure and horizontal gene transfer (HGT) of sludge, but it increases the HGT of kitchen waste, resulting in a dramatic increase of ARGs in KC compost. More attention should be paid to the ARGs risk of kitchen waste composting.

Effect of moisture content, aeration rate, and C/N on maturity and gaseous emissions during kitchen waste rapid composting.

To determine factors affecting compost maturity and gaseous emissions during the rapid composting of kitchen waste, an orthogonal test was conducted with three factors: moisture content (MC) (55%, 60%, 65%), aeration rate (AR) (0.3,0.6 and 0.9 L·kg-1DM·min-1) and C/N ratio (21, 24, 27). The results showed that the importance of factors affecting compost maturity was: C/N > AR > MC, optimal conditions were: C/N of 24, AR of 0.3 L·kg-1DM·min-1and MC of 65%. For gaseous emissions, the sequence of essential factors affecting NH3 emissions was: C/N > MC > AR, and the optimal parameters for NH3 reduction were: C/N of 27, MC of 65%, and AR of L·kg-1DM·min-1. The important factors affecting N2O and H2S emissions are both: MC > C/N > AR, while their best parameters were different. The optimal parameters for N2O emission reduction were MC of 60%, AR of 0.3 L·kg-1DM·min-1 and C/N of 24, while these for H2S were MC of 55%, AR of 0.3 L·kg-1DM·min-1 and C/N of 21. The C/N mainly affected the compost maturity and AR further affected the maturity and pollutant gas emissions by influencing the temperature and O2 content. Considering comprehensively the maturity and gaseous reduction, the optimal control parameters were: MC of 60%-65%, AR of L·kg-1DM·min-1, and C/N of 24-27.

Accelerating the humification of mushroom waste by regulating nitrogen sources composition: Deciphering mechanism from bioavailability and molecular perspective.

Regulating nitrogen source composition is efficient approach to accelerate the spent mushroom substrate (SMS) composting process. However, currently, most traditional composting study only focuses on total C/N ratio of initial composting material. Rarely research concerns the effect of carbon or nitrogen components at different degradable level and their corresponding decomposed-substances on humification process. This study deciphers and compares the mechanism of mixed manure-N sources on SMS humification from bioavailability and molecular perspective. Two different biodegradable manure-N sources, cattle manure (CM) and Hainan chicken manure (CH), were added into the SMS composting with the different CM:CH ratio of 1:0, 3:1, 1:1, 1:3, and 0:1, respectively. The physicochemical properties and humic substances were determined to evaluate the compost quality. Coupling analysis of spectroscopy, fluorescence, and humic intermediate precursors were conducted to characterizing molecular formation process of humic acid (HA). The results indicated that regulating the carbon-nitrogen nutrient biodegradability of composting material by adding mixed nitrogen sources is an effective strategy to accelerate the SMS humification process. The C1H3 (CM:CH ratio of 1:3) and CH treatments obtained great physicochemical properties and the highest growth rate of HA (31.96% and 27.02%, respectively). The rapid reaction of polysaccharide, ketone, quinone, and amide in DOM (LCP1) might be the key for the fast humification in C1H3 and CH. The polyphenol, reducing sugar and amino acid originated from the labile-carbon-proportion I (LCP1) and recalcitrant-carbon-proportion (RCP), labile-carbon-proportion II (LCP2) and RCP, and labile-nitrogen-proportion I (LNP1), respectively, were the main driving intermediate precursors for the formation of HA. This study deciphers the SMS humification mechanism at molecular level and provides a strategy in accelerating-regulating the composting process. which will be beneficial for enhancing the disposing efficiency of SMS, producing high-quality organic fertilizer, and even popularizing to the similar types of organic waste in practical field.

Scandium-Catalyzed Electrochemical Synthesis of α-Pyridinyl Tertiary Amino Acids and Esters.

α-Pyridyl tertiary amino acids have potential pharmaceutical applications because of their structural features. However, their synthesis is still highly limited. Herein, we report a straightforward approach for the electrochemical synthesis of tertiary α-substituted amino acid derivatives via three-component reductive coupling. Using gaseous ammonia as both the N and H source, the α-keto ester reacts directly with 4-CN-pyridine. The application of scandium catalysis is the key for achieving chemoselectivity among various side reaction pathways.

A novel technology for separating live earthworm from vermicompost: Experiment, mechanism analysis, and simulation.

The vermicomposting is widely acknowledged as an effective and sustainable biological technology to dispose large scale organic solid waste such as livestock manure, crop residues and municipal sludge. The scale of vermicomposting has constantly increased over recent years due to high market demand for live earthworms. Rapid and efficient extraction and harvesting earthworm from large-scale vermicompost has become a bottle-neck problem at the end of vermicomposting. Currently, most earthworm separation is done manually or relies on simple tools, and is therefore low efficient, time consuming and labor intensive. In this study, to explore earthworm separation technology and underlying mechanisms, three major studies were conducted based on the developed separator: Earthworm separation experiment, mechanism analysis of separation, and separation process simulation. The result indicated that under a 45% moisture content of vermicompost, earthworm can be separated centrifugally with approximately 83.79% worm separation rate. The treatment capacity of separator is 21.2 kg of total vermicompost mixture per minute. The critical factor in earthworm-vermicompost separation is frictional force and liquid membrane adhesion at the contact interface of conical separator. The final separated X velocity of earthworms is higher, whereas the Y and Z velocities are less than those of vermicompost. The earthworms are centrifugally thrown to a specific area called the earthworm harvest position. The outcome of this study provides a valuable reference for improvement of earthworm harvest efficiency and for shortening the recycling period of vermicomposting products in practice.

Enhancement of biogas production from rape straw using different co-pretreatment techniques and anaerobic co-digestion with cattle manure.

The present study investigated the possibility of valorizing rape straw through anaerobic digestion and the possibility of improving biomethane yield by pretreatment with H2SO4, combined H2SO4 with steam explosion (SE) and SE combined with superfine grinding (SFG). To evaluate the pretreatment method efficiency, several analytical techniques were applied. Additionally, the performance of co-digesting of cattle manure (CM) with pretreated rape straw (PRS) at different ratios was evaluated. The results showed that combined pretreatment could dissolve the lignocellulosic fiber structure, which positively stimulated methane yield. The highest cumulative CH4 yield (CMY) of 305.7 mLg-1VS was achieved by combined SE at 180 °C for 5 min with SFG, which was 77.84% higher than the untreated. The CMY was further improved by 11.4-59% higher than the control (CM) using co-digestion. This study confirmed that, under optimal parameters of AD, pretreatment with SEG180 could significantly boost the CMY from co-digestion of CM and PRS.