Electronic supplementary material.zip from Direct method to determine singular point of enveloped surface and its application to worm wheel tooth surface

A novel methodology for determining the singular point of an enveloped surface is put forward. Unlike some existing methods, the presented method starts directly from the equation of the enveloped surface instead of that of the generating surface, and it is thus called a direct method. The calculation for the normal vector of the enveloped surface is well simplified with the help of the moving frame approach, which makes the presented method feasible. The singularity condition equation is extracted by using the theory of linear algebra. For singular points with different properties, proper solving techniques are established, including resultant elimination and simple elimination. Applying the developed method, the undercutting characteristics of the Archimedes worm wheel are investigated from the perspective of spatial meshing. The numerical results demonstrate that the worm wheel generally has one undercutting limit line, whose trend is along the tooth width of the wheel. Locating on one side of the tooth surface and near the tooth root is a dangerous part of the worm wheel undercutting. The proposed method is beneficial for the development of gear meshing science

Highly Efficient Conversion of Cellulose to Bio-Oil in Hot-Compressed Water with Ultrasonic Pretreatment

Ultrasonic pretreatment was developed to increase conversion of cellulose to bio-oil in hot-compressed water. The physical structures of cellulose were greatly changed by ultrasonic pretreatment, resulting in excellent swelling and dispersion of cellulose in the water. With the increased surface area and decreased crystallinity and degree of polymerization of cellulose, the bio-oil yield was increased remarkably. The highest bio-oil yield (61.5%) was obtained at 260 °C with a residence time of 0 min for the 1 h pretreated cellulose. Under the optimum reaction conditions, ultrasonic pretreatment increased the bio-oil yield by 22.1% and reduced residence time by 5 min. GC-MS analysis results showed that ultrasonic pretreatment affected the chemical compositions of bio-oils and significantly improved the content of 5-hydroxymethylfurfural in heavy oils

Conversion of Cornstalk to Bio-oil in Hot-Compressed Water: Effects of Ultrasonic Pretreatment on the Yield and Chemical Composition of Bio-oil, Carbon Balance, and Energy Recovery

An ultrasonic pretreatment method was developed to enhance the yield of bio-oil obtained from the liquefaction of cornstalks in hot-compressed water at different reaction temperatures (260–340 °C) and residence times (0–40 min). Influences of ultrasonic pretreatment on the physicochemical properties of cornstalks and bio-oil yields were investigated. The results show that ultrasonic pretreatment obviously increases surface areas of cornstalks, decreases crystallinities, and erodes the structures of lignin, leading to more exposure of cellulose and hemicellulose. The yield of bio-oil was increased remarkably by 10.1% for 40 min sonicated cornstalks under the optimum liquefied conditions (300 °C for 0 min of residence time). Carbon balance indicates that ultrasonic pretreatment increases the carbon conversion of cornstalks to heavy oil and water-soluble oil. Energy balance indicates that the sonicated cornstalks have positive energy efficiencies. GC-MS analyses demonstrate ultrasonic pretreatment increases the contents of the phenols in heavy oil and water-soluble oil

One-Pot Conversion of Bio-oil to Diesel- and Jet-Fuel-Range Hydrocarbons in Supercritical Cyclohexane

This study demonstrates a new route for converting bio-oil, prepared from the hydrothermal liquefaction of cornstalks, to diesel- and jet-fuel-range hydrocarbons over Ni/ZrO₂ in supercritical cyclohexane. Under relatively mild conditions (573 K, 5 MPa H₂), we obtained a high yield (81.6 C%) of hydrocarbons with an excellent quality (90% of diesel- and jet-fuel-range hydrocarbons and 7% of gasoline-range hydrocarbons). Ni/ZrO₂ efficiently and stably catalyzed all types of compounds in the bio-oil to the corresponding alkanes via hydrogenation, dehydration, hydrogenolysis, decarbonylation, and isomerization, without polymerizations among the different reactive compounds in bio-oil. The activity and selectivity for diesel- and jet-fuel-range hydrocarbons of Ni/ZrO₂ showed no obvious changes after three cycles. Ni/ZrO₂ was fairly stable in supercritical cyclohexane after 72 h of reaction time. This strategy provides a novel high-efficiency pathway for the preparation of high-quality hydrocarbons from bio-oil

Inkjet Printing Patterns of Highly Conductive Pristine Graphene on Flexible Substrates

Highly conductive pristine graphene electrodes were fabricated by inkjet printing using ethyl cellulose-stabilized ink prepared from pristine graphene. Pristine graphene was generated by exfoliation from graphite using ultrasound-assisted supercritical CO₂. The ink, at concentrations up to 1 mg/mL, was stable for more than 9 months and had compatible fluidic characteristics for efficient and reliable inkjet printing. The inkjet printing patterns of the graphene on diverse substrates were uniform and continuous. After 30 printing passes and annealing at 300 °C for 30 min, the printed films developed a high conductivity of 9.24 × 10³ S/m. The resistivity of the printed electrodes on the flexible substrates increased by less than 5% after 1000 bending cycles and by 5.3% under a folding angle of 180°. The presented exfoliated pristine graphene and the corresponding efficient methods for formulating the ink and fabricating conductive electrodes are expected to have high potential in applications involving graphene-based flexible electronic devices

Sunlight-Assisted Degradation of Dye Pollutants in Ag₃PO₄ Suspension

Sunlight-induced photodegradation of rhodamine B over Ag₃PO₄ has been observed. Nanosized Ag₃PO₄ was synthesized by a facile ion-exchange route. X-ray powder diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, the Brunauer–Emmett–Teller surface area, UV–vis diffuse reflectance spectroscopy and photoluminescence spectra were employed to investigate the phase structure, morphology and optical property of the Ag₃PO₄ product. Nearly 100% of rhodamine B was degraded after a very short irradiation time using simulated sunlight in Ag₃PO₄ suspension, and the total organic carbon measurement revealed that a high degree of mineralization was achieved in the present photocatalytic system. Ag₃PO₄ catalyst has an excellent photocatalytic performance due to the high separation efficiency of electron and hole pairs. In the neutral pH solution, Ag₃PO₄ catalyst exhibited the best photoactivity under simulated sunlight. The photoinduced holes were considered to be the dominant active species in the photodegradation process

Inkjet Printing Patterns of Highly Conductive Pristine Graphene on Flexible Substrates

Highly conductive pristine graphene electrodes were fabricated by inkjet printing using ethyl cellulose-stabilized ink prepared from pristine graphene. Pristine graphene was generated by exfoliation from graphite using ultrasound-assisted supercritical CO₂. The ink, at concentrations up to 1 mg/mL, was stable for more than 9 months and had compatible fluidic characteristics for efficient and reliable inkjet printing. The inkjet printing patterns of the graphene on diverse substrates were uniform and continuous. After 30 printing passes and annealing at 300 °C for 30 min, the printed films developed a high conductivity of 9.24 × 10³ S/m. The resistivity of the printed electrodes on the flexible substrates increased by less than 5% after 1000 bending cycles and by 5.3% under a folding angle of 180°. The presented exfoliated pristine graphene and the corresponding efficient methods for formulating the ink and fabricating conductive electrodes are expected to have high potential in applications involving graphene-based flexible electronic devices

Exfoliation of Graphite into Graphene by a Rotor–Stator in Supercritical CO₂: Experiment and Simulation

High-shear-induced exfoliation of graphite into graphene using a rotor–stator mixer in supercritical CO₂ is a promising approach to massively produce high-quality graphene. The exfoliation mechanism of the rotor–stator and its geometry influence on the exfoliation yield were investigated in this work. The results showed that the active region of peeling off graphite to graphene was located between the rotor (including the rotating fluid) and the stator, in which the velocity gradient was the highest. The exfoliation time was valid only when the graphite particles fell in the active region. The volume of the effective area and the active exfoliation time affected the graphene yield significantly. The optimal ratio of the wall area of the stator is about 80%. Both the lengthened rotor–stator and the multiwall stators increased the yield by 40%. Also, the similar results were obtained in other solvents like water and NMP by the optimal structure of the rotor–stator in terms of exfoliation efficiency. The findings pave the way to scale up the approach of a rotor–stator mixer in supercritical CO₂ for the industrial-scale production of graphene

Wearable Solid-State Supercapacitors Operating at High Working Voltage with a Flexible Nanocomposite Electrode

The proposed approach for fabricating ultralight self-sustained electrodes facilitates the structural integration of highly flexible carbon nanofibers, amino-modified multiwalled carbon nanotubes (AM-MWNT), and MnO₂ nanoflakes for potential use in wearable supercapacitors. Because of the higher orientation of AM-MWNT and the sublimation of terephthalic acid (PTA) in the carbonization process, freestanding electrodes could be realized with high porosity and flexibility and could possess remarkable electrochemical properties without using polymer substrates. Wearable symmetric solid-state supercapacitors were further assembled using a LiCl/PVA gel electrolyte, which exhibit a maximum energy density of 44.57 Wh/kg (at a power density of 337.1 W/kg) and a power density of 13330 W/kg (at an energy density of 19.64 Wh/kg) with a working voltage as high as 1.8 V. Due to the combination of several favorable traits such as flexibility, high energy density, and excellent electrochemical cyclability, the presently developed wearable supercapacitors with wide potential windows are expected to be useful for new kinds of portable electric devices

Table_1_Whole genome sequencing of OXA-232-producing wzi93-KL112-O1 carbapenem-resistant Klebsiella pneumoniae in human bloodstream infection co-harboring chromosomal ISEcp1-based blaCTX-M-15 and one rmpA2-associated virulence plasmid.docx

ObjectivesTo characterize one OXA-232-producing wzi93-KL112-O1 carbapenem-resistant Klebsiella pneumoniae (CRKP) co-harboring chromosomal blaCTX-M-15 and one rmpA2-associated virulence plasmid.MethodsMinimum inhibitory concentrations (MICs) were measured via broth microdilution method. Conjugation, chemical transformation, string test and Galleria mellonella infection model experiments were also conducted. Whole-genome sequencing (WGS) was performed on the Illumina and Nanopore platforms. Antimicrobial resistance determinants were identified using ABRicate program with ResFinder database. Insertion sequences (ISs) were identified using ISfinder. Bacterial virulence factors were identified using virulence factor database (VFDB). Wzi, capsular polysaccharide (KL) and lipoolygosaccharide (OCL) were analyzed using Kleborate with Kaptive. Phylogenetic analysis of 109 ST15 K. pneumoniae strains was performed using core genome multilocus sequence typing (cgMLST) on the Ridom SeqSphere+ server. MLST, replicons type, SNP strategies and another cgMLST analysis for 45 OXA-232-producing K. pneumoniae strains were further conducted using BacWGSTdb server.ResultsK. pneumoniae KPTCM strain belongs to ST15 with wzi93, KL112 and O1. It possessed a multidrug-resistant (MDR) profile and was resistant to carbapenems (meropenem and ertapenem), ciprofloxacin and amikacin. Virulence assays demonstrated KPTCM strain possesses a low virulence phenotype. WGS revealed it contained one circular chromosome and nine plasmids. The carbapenemase-encoding gene blaOXA-232 was located in a 6141-bp ColKP3-type non-conjugative plasmid and flanked by ΔISEcp1 and ΔlysR-ΔereA. Interestingly, blaCTX-M-15 was located in the chromosome mediated by ISEcp1-based transposon Tn2012. Importantly, it harbored a rmpA2-associated pLVPK-like virulence plasmid with iutA-iucABCD gene cluster and one IS26-mediated MDR fusion plasmid according to 8-bp (AGCTGCAC or GGCCTTTG) target site duplications (TSD). Based on the cgMLST and SNP analysis, data showed OXA-232-producing ST15 K. pneumoniae isolates were mainly isolated from China and have evolved in recent years.ConclusionsEarly detection of CRKP strains carrying chromosomal blaCTX-M-15, OXA-232 carbapenemase and pLVPK-like virulence plasmid is recommended to avoid the extensive spread of this high-risk clone.</p