Mixture Of Peroxide Research Articles

Hydrogen from bottle-the magic of Pt catalysts for methanol reforming instantly start-up from cold weather

Hydrogen is a clean energy carrier, but does not occur naturally. Here we reported a novel process to get instant hydrogen from a mixture of methanol and dilute hydrogen peroxide. The hydrogen can be obtained instantly once the fuel mixture is in contact with the platinum catalyst without any external heating or any energy input. The catalyst can be started and stopped more than 100 times before a new load of catalyst is required. Pure hydrogen is produced by combining the reforming catalyst with a water gas shift catalyst bed, which is driven by heat from the reforming process. Interestingly we discovered that only platinum catalysts can synergistically activate methanol and hydrogen peroxide to give hydrogen spontaneously. The preparation conditions and impurities have significant effects on the reforming process. This work overcomes the various hurdles of on-board reforming for hydrogen production and provides a way to catalyse the utilization of fuel cells.

Fabrication of microfibrillated cellulose gel from waste pulp sludge via mild maceration combined with mechanical shearing

This article describes a facile route, which combines mild maceration of waste pulp sludge and a mechanical shearing process, to prepare microfibrillated cellulose (MFC) with a high storage modulus. In the maceration, the mixture of glacial acetic acid and hydrogen peroxide was used to extract cellulose from never-dried waste pulp sludge. Then, two different mechanical processes including disc refining (DR) and ultrasonication plus homogenization (UH) were applied to the cellulose after maceration and resulted in MFC with a highly tangled fibril network. All of the resultant cellulosic suspensions (2 % w/w) exhibited a gel-like and shear-thinning behavior with storage moduli (G′) ranging from 200 to 4000 Pa. Among them, the 30-min DR-treated MFC gels had the maximum G′, which was much higher than for previously reported MFC gels at the same concentration. Additionally, after mechanical processing, specific surface areas and water retention values of MFC were accordingly increased with the enhancement of shear force, while the storage moduli (G′) were not consistently increased. Finally, a strong MFC gel was successfully prepared from never-dried waste pulp sludge via a one-step disc refining process and using cost-effective chemicals. The obtained hydrogels will have potential as low-density reinforcing fillers or as a template for further surface modification.

Synthesis and structure determinantion of the first lead arsenide phosphide Pb2As x P14–x (x ~ 3.7)

Abstract Pb2As x P14–x was synthesized by reacting the pnicogens in a lead melt in sealed silica ampoules. A mixture of hydrogen peroxide and glacial acetic acid removed lead from the final product. Pb2As x P14–x represents the first lead arsenide phosphide adopting a new structure type. Systematic substitution of phosphorus by arsenic leads to the formation of Pb2As x P14–x with x ~ 3.7, a compound with a two-dimensional arrangement of polypnictide layers, coordinated by Pb2+ cations. Pb2As x P14–x is structurally related to PbP7 where a three-dimensional polyphosphide network is realized instead. The structure of Pb2As3.7(1)P10.3(1) was determined from single crystal X-ray diffraction data: space group P212121 (no. 19), a = 10.060(1), b = 10.500(1), c = 13.711(2) Å, and V = 1448.3(4) Å3. The structure is discussed relative to PbP7 focusing on the differences in the polyanionic substructures of the two polypnictides.

Removal of Ion-Implanted Photoresist on GaAs Surface Using Organic Solvents

Scaling down of silicon-based transistors is facing various problems such as increase in the gate leakage and power consumption. As a solution to resolve those problems, III-V compound semiconductors are introduced as a channel material. Because III-V compound semiconductors have outstanding electron transport properties, they can enable the downscaling of transistors [1,2]. However, the introduction of III–V compound semiconductors into Si-based infrastructures and manufacturing processes still have many problems to be solved. One of the largest problems is the removal of photoresists on III–V compound semiconductors. In the general Si-based manufacturing process, sulfuric acid and hydrogen peroxide mixture (SPM) or ozonated water is used to remove photoresist. However, such chemicals may not be used on III–V compound semiconductors because they etch or oxidize III-V compounds [3]. Also, photoresist removal process should be achieved at low temperature to avoid the surface damage of semiconductor. Therefore, photoresist removal process using organic solvents at room temperature that cause no material loss of III-V compounds was conducted in our study. Both ArF photoresist on GaAs wafer and KrF photoresist on trench patterned GaAs wafer were tested. Implantation was conducted with P ions on both photoresists at doses of 5 × 1013, 5 × 1014, and 5 × 1015 atoms/cm2 at 30 keV and 10-6Pa. Implanted ArF and KrF photoresists on GaAs wafer were removed using two different organic solvents in sequence to reduce photoresist removal process temperature. Low molar volume solvents (formamide, acetonitrile, nitromethane, and monoethanolamine (MEA)) were tested as the first step solvent in the two-step photoresist removal process and dimethyl sulfoxide (DMSO) which has high affinity to photoresist was selected as the second step solvent. The implanted photoresists on GaAs were dipped in each solvent for various times from 5 to 30 min. In order to evaluate the photoresist removal efficiency, field-emission scanning electron microscopy (FE-SEM) and optical microscope were used. Also, to analyze the reactivity of organic solvents with GaAs, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were conducted. In case of formamide + DMSO two-step treatment, while ArF photoresists implanted at doses of 5 × 1013 and 5 × 1014 atoms/cm2 were removed, photoresist implanted at 5 × 1015 atoms/cm2 could not be removed, even after dipping in each solvent for 30 min. Nitromethane and MEA + DMSO showed similar results with formamide + DMSO. However, two-step treatment with acetonitrile + DMSO resulted in complete removal of ArF photoresist implanted at doses of 5 × 1013 , 5 × 1014 and even 5 × 1015 atoms/cm2 after dipping for 15 min in each solvent (Fig.1). The behavior of photoresist removal in different organic solvents can be explained by combining the permeability of solvents through photoresist, which is controlled by molecular size, and the affinity of solvents with photoresist, as shown in Fig. 2. The first step solvents can easily permeate into the crust because they have low molar volume (>60 cm3/mol), and the second step solvent which has higher affinity (RED < 1) dissolves the photoresist. AFM (Fig. 3) and XPS results show that there is no damage on the GaAs surface after the treatment with acetonitrile + DMSO two-step process. Figure 1

RT Atomic Layer Deposition of ZrO2 By Using Plasma Excited Water Vapor

Size of semiconductor devices in large-scale integration has reached the submicron range where gate oxide films in metal oxide semiconductor (MOS) devices need to be fabricated at a nanometer scale. Atomic layer deposition (ALD) is a technology for depositing dielectric films with monolayer precision by repeating adsorption of a source gas on substrate that is subsequently reactivated for further adsorption [1]. Zirconium oxide (ZrO2) is believed to be a candidate as the high-k gate oxide material [2]. The growth temperature for the ZrO2 deposition has been desired to be decreased to near room temperature (RT) because the interfacial layer is formed by the solid phase reaction with heating process [3]. In this work, we developed a RT atomic layer deposition of ZrO2 with tetrakis (ethylmethylamino) zirconium (TEMAZ) and a remote-plasma excited water vapor.A p-type Si(100) substrate with a resistivity of 8-12 Ωcm was used as a sample. Prior to the experiment, the sample was cleaned with a buffered HF acid solution and sulfuric acid-hydrogen peroxide mixture. TEMAZ as the zirconium precursor was introduced with a variable leak valve. An induction plasma system generating oxidizing gas was installed to the ALD chamber as shown in Fig.1. The source gas for the oxidizing gas is a mixture of H2O vapor and Ar gas. The plasma was generated in a glass tube with an induction coil with a frequency of 13.56MHz and a RF power of 30 W. Before the ALD process, the substrate surface was treated with the plasma excited water vapor for 5 min to be terminated with OH groups. For the ZrO2 deposition, we repeated the cycle of TEMAZ saturation and the oxidizing gas treatment at RT. The TEMAZ exposure was set to 1.12×10-3 Torr×100 s. The saturation of TEMAZ on the hydroxylated surface has been confirmed by the IR absorption spectroscopy. The plasma excited oxidizing gas was injected for 150 s. The oxidization state of the ZrO2 film was evaluated by X-ray photoelectron spectroscopy (XPS). The thickness of the grown film was measured by spectroscopic ellipsometry.Fig.2 shows Zr3d spectra obtained from ZrO2 on Si grown by the present ALD. According to the increase in the ALD cycles, the Zr3d5/2 peak at around 181.9 eV evolves. The peak position indicates the full oxidized ZrO2 growth on Si [4]. Fig.3 shows the ZrO2 thickness as a function of the ALD cycle. The linear increase of ZrO2 thickness with the ALD cycle indicates that the ZrO2 is grown in the ALD mode. The growth rate is estimated to be 0.14 nm/cycle. This value is comparable with those released in the conventional thermal ALD studies [5].To conclude, we developed the non-heating, RT ALD of ZrO2 with the plasma enhanced technology. We are now investigating the electrical characteristics of ZrO2 MOS on Si and Ge, which will be released elsewhere. The RT grown ZrO2 films might be also applicable for the anticorrosion coatings on plastic material. In the conference, we present not only the details of growth experiment but also discuss the growth kinetics of RT ALD.Acknowledgement This work was partly supported by JST-CREST. We would like to express the deepest appreciation to AIR-LIQUIDE for the high quality precursor of TEMAZ.

Analysis of dietary minerals in selected seeds and nuts by using ICP-OES and assessment based on the recommended daily intakes

Purpose– Seeds and nuts include many dietary minerals as well as trace metals. It is very important to determine the nutritional mineral values in seeds and nuts. Many minerals can be analyzed simultaneously in low concentrations by using inductively coupled plasma-atomic emission spectroscopy. This paper aims to evaluate nutritional values of dietary and trace minerals in selected seeds and nuts.Design/methodology/approach– Dietary minerals in the sunflower seed (Helianthus annuus), pumpkin seed (Cucurbita pepoL.), peanut (Arachis hypogaea) and corn (Zea maysL.) samples collected from the markets in Sakarya city of Turkey have been analyzed. Two digestion procedures were applied by using hydrochloric acid solution and the mixture of nitric acid and hydrogen peroxide solution.Findings– In the evaluation of the mineral contributions of the nuts, the micro-mineral contributions (Cu, Fe, Zn, Mn and Se) were found at higher values than the macro-minerals (Ca, Mg, K and Na). Potassium was determined as the most abundant mineral, and sodium was found at lower levels. The results showed that nuts are trace mineral suppliers and possible Na-K regulator foods in human nutrition.Social/implications– The obtained results for the mineral profile and daily intake values provide useful information that could sensitize the people on the consumption of seeds and nuts.Originality/value– Findings from the digestion procedures and the assessments based on the recommended daily intakes have got valuable impact.

A Novel Sonochemical Approach for Enhanced Recovery of Carbon Fiber from CFRP Waste Using Mild Acid–Peroxide Mixture

A novel sonochemical method is proposed for the recovery of carbon fiber from carbon fiber reinforced polymer (CFRP) composites by treatment with a mixture of dilute nitric acid and hydrogen peroxide in the presence of ultrasound. A maximum resin decomposition ratio of 95% could be obtained for the epoxy matrix. SEM and TGA data showed that the recovered fibers had very little or no epoxy resin and their tensile strength was comparable to that of the virgin fiber. ATR-FTIR, MALDI-TOF/MS, and 1H NMR analysis of the recovered solid and liquid byproducts showed the formation of decomposition products of cross-linked epoxy resin through nitration and oxidation reactions. This process opens the possibilities of an environmentally more benign process for CFRP waste decomposition and recovery of carbon fiber in the presence of ultrasound and H2O2 by eliminating the need for strong chemicals and high reaction temperatures and pressures.

Preparation and Characterization of Maleic Anhydride Grafted Poly(Hydroxybutirate-CO-Hydroxyvalerate) – PHBV-g-MA

A compatibilizer agent was successfully produced by grafting maleic anhydride (MA) to poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) chains on a reactive processing by mechanical mixing, using a mixture of PHBV, MA and dicumyl peroxide (DCP) as initiator. The resulting PHBV grafted MA (PHBV-g-MA) was characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and gel permeation chromatography (GPC), and its properties were compared to neat PHBV. FTIR showed an absorption band at 699 cm-1 for PHBV-g-MA, related to CH group of grafted anhydride ring. The initial thermal degradation temperature of the compatibilizer agent was reduced when compared to neat PHBV. DSC analysis showed that after grafting MA onto PHBV the crystallization temperature was about 20oC higher than neat PHBV, and the degree of crystallinity was increased. GPC analysis showed that MA when grafted onto PHBV led to a reduction of molecular weight and polydispersity.

Improved tooth bleaching combining ozone and hydrogen peroxide—A blinded study

ObjectivesTo evaluate the efficacy of tooth bleaching using ozone after hydrogen peroxide (H2O2) in comparison to the use of H2O2 alone. Methods70 extracted teeth were randomly distributed into two groups. Teeth surfaces in group 1 (n=35) were treated using 38% H2O2 and then were exposed to ozone for 60s and this ozonated peroxide mixture was left on the teeth for 20min. Meanwhile, teeth in group 2 (n=35) were treated with H2O2 38% for 20min. The L* a* b* and Vita Classic shade values of teeth were evaluated in both groups at base line, after application of H2O2 and ozone in group 1, and after application of H2O2 and then again after another application of ozone in group 2. The statistically significant changes were set at P≤0.05. ResultsBaseline L* a* b* and Vita shade values were comparable between groups (P>0.05). Teeth obtained lighter shades following bleaching with both H2O2 and ozone or with H2O2 alone (P≤0.05). Further bleaching with ozone for teeth already bleached with H2O2 alone showed further improvement of the shades of teeth (P<0.001). Teeth treated with H2O2 and ozone had more shade improvements than those only treated with H2O2 (P<0.001). Also, L* values were increased while b* values were decreased (teeth obtained lighter shades) following bleaching in both groups (P≤0.05). More changes were obtained when both ozone and H2O2 were used (P≤0.05). ConclusionsBleaching with 38% H2O2 and ozone resulted in teeth with lighter shades than bleaching with 38% H2O2 alone.

Gold core@silver semishell Janus nanoparticles prepared by interfacial etching

Gold core@silver semishell Janus nanoparticles were prepared by chemical etching of Au@Ag core-shell nanoparticles at the air/water interface. Au@Ag core-shell nanoparticles were synthesized by chemical deposition of a silver shell onto gold seed colloids followed by the self-assembly of 1-dodecanethiol onto the nanoparticle surface. The nanoparticles then formed a monolayer on the water surface of a Langmuir-Blodgett trough, and part of the silver shell was selectively etched away by the mixture of hydrogen peroxide and ammonia in the water subphase, where the etching was limited to the side of the nanoparticles that was in direct contact with water. The resulting Janus nanoparticles exhibited an asymmetrical distribution of silver on the surface of the gold cores, as manifested in transmission electron microscopy, UV-vis absorption, and X-ray photoelectron spectroscopy measurements. Interestingly, the Au@Ag semishell Janus nanoparticles exhibited enhanced electrocatalytic activity in oxygen reduction reactions, as compared to their Au@Ag and Ag@Au core-shell counterparts, likely due to a synergistic effect between the gold cores and silver semishells that optimized oxygen binding to the nanoparticle surface.

Cross-Linkable Epoxidized Maleinated Castor Oil: A Renewable Resin Alternative to Unsaturated Polyesters

As an alternative resin to conventional synthetic unsaturated polyesters (UPEs), epoxidized maleinated castor oil (EMACO) was synthesized in two steps. For this purpose, castor oil was reacted with maleic anhydride at 70°C to obtain maleinated castor oil (MACO). Then, epoxidation of MACO was carried out by using a mixture of formic acid and hydrogen peroxide at 0–5°C. Then, the free carboxyl groups of the synthesized EMACO were further reacted with free epoxide groups of EMACO at 90°C. At the end of the reaction, an unsaturated polyester precursor-prepolymer was obtained (P-EMACO). FTIR and1H NMR spectroscopic techniques were used to characterize the monomers synthesized. The P-EMACO was then mixed with styrene and cross-linked in the presence of AIBN at 50°C. Thermal and mechanical properties of the final cross-linked product were investigated by thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA) techniques. The degradation onset temperature of the material at which cross-linked X-EMACO loses 5% of its weight was found to be 209°C. Its dynamicTgand storage modulus at 25°C were determined as 72°C and 1.08 GPa, respectively. These results are higher than some of the different oil based polymers reported in the literature.

Concentrations and exposure risks of some metals in facial cosmetics in Nigeria.

The concentrations of nine metals (Cd, Pb, Ni, Cr, Co, Cu, Fe, Mn and Zn) were determined in lip sticks, lip glosses, lip balms, eye pencils, eyeliners, eye shadows, blushes, mascaras and face powders. The study was aimed at providing information on the risk associated with human exposure to metals in these facial cosmetic products. The concentrations of metals in the samples were measured by atomic absorption spectrometry after digestion with a mixture of nitric acid, hydrochloric acid and hydrogen peroxide. The mean concentrations of metals in these facial cosmetics ranged from 3.1 to 8.4 μg g−1 Cd, 12–240 μg g−1 Pb, 9.1–44 μg g−1 Cr, 18–288 μg g−1 Ni, 1.6–80 μg g−1 Cu, 7.9–17 μg g−1 Co, 2.3–28 mg g−1 Fe, 12–230 μg g−1 Mn, and from 18 to 320 μg g−1 Zn. The concentrations of Ni, Cr and Co were above the suggested safe limit of 1 μg g−1 for skin protection, while Cd and Pb were above the Canadian specified limits. The systemic exposure dosage (SED) values for these metals obtained from the use of these facial cosmetic products were below their respective provisional tolerable daily intake (PTDI)/or recommended daily intake (RDI) values. The margin of safety values obtained were greater than 100 which indicated that the concentrations of the metals investigated in these facial cosmetics do not present considerable risk to the users except in the case of face powders.

Approach to graft bioactive polymers on titanium implants by UV irradiations

Event Abstract Back to Event Approach to graft bioactive polymers on titanium implants by UV irradiations Hamza Chouirfa1, Céline Falentin-Daudré1 and Véronique Migonney1 1 LBPS-CSPBAT UMR CNRS 7244, Université Paris 13, France Introduction: Titanium is widely used in orthopedic implants for its excellent resistance to corrosion and its biocompatibility. Nevertheless and despite the prevention rules, 1.5 to 2 % of implanted prostheses are still subject to bacterial infections, threatening their benefit on a long-term basis. That’s the reason why chemical modification of titanium surfaces to confer desirable functional properties is required. In order to prevent bacteria and improve the long-term osteointegration of titanium, bioactive polymers bearing ionic groups (sulfonate) were covalently grafted onto titanium surfaces. Classically, the grafting used the heat to create radicals and lasted more than half day[1]-[6]. We have elaborated a new approach to create radicals (UVs) in only one hour[7]. Methods: Grafting procedure (Figure 1): Titanium surface were cleaned by successive 10 min ultrasound treatments in a bath of distilled water. After drying, samples were oxidized in a solution containing the same volume of pure H2SO4 and H2O2 (30%). After oxidation, samples were rinsed thoroughly in distilled water and then placed directly into a mechanically stirred solution of the monomers. After UV initiation of the radical polymerization, samples were rinsed thoroughly in distilled water and dried. Results and Discussion: Ionic groups (sulfonate) were covalently attached to the titanium surfaces by radical polymerization of sodium styrene sulfonate (NaSS) initiated by radicals issued from titanium peroxide. Immersion of titanium samples in a mixture of pure sulphuric acid and hydrogen peroxide produces on its surface titanium hydroxide and titanium peroxide. The decomposition of titanium peroxide in radicals was been produced by UV irradiations. Amounts of grafted polymers were measured by colorimetric method. Other techniques were used to check the presence of the bioactive polymers at the surface of titanium samples: XPS analysis, IR-ATR, Contact angle analysis. The grafting by UV way showed same results than thermal way, yet the UV way is the fastest (15 times faster). Conclusion: In the last decade, many studies have been devoted to improving the bone cell-implant interaction, with the goal of improving the osseointegration of devices for dental and orthopaedic applications. There are various ways to modify surface implants, and our strategy is to graft polymer model at their surface in using the UVs. The advantage of our method is that the coating is linked by a covalent bond to the titanium substrates. Surface characterization techniques have shown that the UV grafting of bioactive polymers at the surface of titanium reaches 5 µg.cm-2 like by thermal grafting. Our approach is interesting from an industrial point of view because it also needs few time and few quantity of monomers to obtain a high yield of polymer grafting. Excellent biological results were been obtained by thermal grafting and we would like to check biologically the UV grafting. Figure 1: Grafting of bioactive polymers on titanium surfaces.

Etching of germanium-tin using ammonia peroxide mixture

The wet etching of germanium-tin (Ge1-xSnx) alloys (4.2% &amp;lt; x &amp;lt; 16.0%) in ammonia peroxide mixture (APM) is investigated. Empirical fitting of the data points indicates that the etch depth of Ge1-xSnx is proportional to the square root of the etch time t and decreases exponentially with increasing x for a given t. In addition, X-ray photoelectron spectroscopy results show that increasing t increases the intensity of the Sn oxide peak, whereas no obvious change is observed for the Ge oxide peak. This indicates that an accumulation of Sn oxide on the Ge1-xSnx surface decreases the amount of Ge atoms exposed to the etchant, which accounts for the decrease in etch rate with increasing etch time. Atomic force microscopy was used to examine the surface morphologies of the Ge0.918Sn0.082 samples. Both root-mean-square roughness and undulation periods of the Ge1-xSnx surface were observed to increase with increasing t. This work provides further understanding of the wet etching of Ge1-xSnx using APM and may be used for the fabrication of Ge1-xSnx-based electronic and photonic devices.

The study of the quantification of the concentration of benzoyl peroxide based on the terahertz spectrum

The quantitative regression analysis of the mixture based on the terahertz spectrum is reported in this paper. The absorption spectrum and the refractive index spectrum of a mixture of benzoyl peroxide and polyethylene were obtained by calculation, and then a mixture of benzoyl peroxide and polyethylene was used experimentally, and then the spectrum obtained was preprocessed using the method of wavelet filter, first derivative model and second derivative model. Partial least squares regression and kernel partial least squares regression were applied to the modelling of the regression analysis of the original absorption spectrum, the first derivative model and second derivative model spectra, and a detailed performance evaluation is presented at the end of the paper.

COMBINED NUMERICAL FINITE ELEMENT AND EXPERIMENTAL OPTIMIZATION APPROACH IN THE PRODUCTION PROCESS OF MEDIUM-VOLTAGE, RUBBER-INSULATED ELECTRIC CABLES VULCANIZED WITH STEAM WATER. PART 2: NUMERICAL SIMULATIONS AND INVERSE ANALYSES

ABSTRACT A comprehensive, combined, numerical model is presented, based on genetic algorithm (GA) optimization and heat-transfer finite-element computations. The numerical analyses were carried out to evaluate the final cross-linking degree of a medium-voltage electric cable subjected to industrial peroxide reticulation. The difference between numerically predicted and experimentally determined cross-linking degree along the thickness of the insulator is then minimized, when a variable steam-temperature profile along the pipe length is assumed to explain the unexpected undervulcanization of the cable in the internal layers. To minimize the gap between the experimentally determined degree of curing and numerical predictions, a GA optimization is used for best fit, instead of the steepest-descendent, standard least-squares, which is not applicable in this case because the objective function is not analytically known. The cable was supposedly vulcanized under four different conditions. The degree of cross-linking is experimentally obtained by determining the differential scanning calorimetry (DSC) of the nondecomposed peroxide from the external layer to the core of the cable. The proposed GA approach exploits a specifically crafted, zooming strategy, consisting of the subdivision of the population at each iteration into two subgroups, depending on the individual's grade of fitness (elitist strategy). The integrated, numerical, experimental approach allows optimization of the amount of peroxide in the compound and comparison of the performances of different peroxide mixtures. The degree of cross-linking compliance can be obtained as a function of the temperature gradient measured in the steam pipe. Production conditions can be automatically calculated according to the cable parameters, by increasing the quality reliability and reducing the scraps.

A multi-scale simulation method for the prediction of edge wicking in multi-ply paperboard

When liquid packaging board is made aseptic in the filling machine the unsealed edges of the board are exposed to a mixture of water and hydrogen peroxide. A high level of liquid penetration may lead to aesthetic as well as functional defects. To be able to make a priori predictions of the edge wicking properties of a certain paperboard material is therefore of great interest to the paper industry as well as to packaging manufacturers. In this paper an extended multi-scale model of edge wicking in multi-ply paperboard is presented. The geometric and physical properties of the paperboard are modeled on the micro-scale, and include fillers and fines. The absolute air permeabilities and pore size distributions are validated with experimental and tomographic values. On the macro-scale random porosity and sizing distributions, time and sizing dependent contact angles, and inter-ply dependence are modeled. Arbitrary shapes of the paperboard are handled through an unstructured 3D surface mesh. Stationary and transient edge wicking simulations are validated against experiments with excellent agreement. The simulations show that the diffusive menisci between the liquid and air phases together with the two-ply model is necessary to achieve good agreement with the transient edge wicking experiments.

The Effect of Different Reduction Methods on Conductivity of Reduced-Graphene Oxide (r-GO)

Large quantity of graphene oxide (GO) was prepared by Modified Hummer’s method, in which graphite was treated with a mixture of sulphuric acid, potassium permanganate and hydrogen peroxide. A chemically reduced graphene oxide (r-GO) was prepared using sodium borohydride (NaBH4), followed by thermal treatment and thermal treatment of chemically reduce using NaBH4. The electrical resistance of r-GO was measured using Keithley sourcemeter. The results revealed that r-GO show lower resistance on thermal reduction which is 2.39 kΩ compared to chemical reduction and thermal of NaBH4reduction which is 2.18 MΩ and 3.16 kΩ respectively. It can be concluded that thermal reduction is the best method to produce high conductivity r-GO film.

Lipid Metabolites from the MushroomMeripilus giganteus

The phytochemical investigation of the methanolic extract of the white rot fungus Meripilus giganteus resulted in the isolation and identification of complex mixtures of free fatty acids (1), monoacylglycerols (2), cerebrosides (3), ergosterol (4) and ergosterol peroxide (5). The structures of the isolated lipid metabolites (1-5) were determined by chemical and spectroscopic methods. The antioxidant activity of the whole MeOH extract of the fungus was evaluated through in vitro model systems, such as 2,2-diphenyl-l-picrylhydrazyl (DPPH) and superoxide anion. In all two systems, the results indicated that the extract of the fungus showed the same free-radical-scavenging activity with SC50 data of 47.70 µg/mL, compared with the positive control quercetin (DPPH assay). None of the isolated compounds (1-5) showed a significant activity. Compounds 2-4 were isolated from Meripilus giganteus for the first time.

Efficient processing of reaction-sintered silicon carbide by anodically oxidation-assisted polishing

Reaction-sintered silicon carbide (RS-SiC) is a promising optical material for the space telescope systems. Anodically oxidation-assisted polishing is a method to machine RS-SiC. The electrolyte used in this study is a mixture of hydrogen peroxide (H2O2) and hydrochloric acid (HCl), and the oxidation potential has two modes: constant potential and high-frequency-square-wave potential. Oxide morphologies are compared by scanning electron microscope/energy dispersive x-ray spectroscopy and scanning white-light interferometer. The results indicate that anodic oxidation under constant potential can not only obtain a relatively smooth surface but also be propitious to obtain high material removal rate. The oxidation depth in anodic oxidation under constant potential is calculated by comparing surface morphologies before and after hydrofluoric acid etching. The theoretical oxidation rate is 5.3 nm/s based on the linear Deal–Grove model. Polishing of the oxidized RS-SiC is conducted to validate the machinability of the oxide layer. The obtained surface roughness root-mean-square is around 4.5 nm. Thus, anodically oxidation-assisted polishing can be considered as an efficient method, which can fill the performance gap between the rough figuring and fine finishing of RS-SiC. It can improve the machining quality of RS-SiC parts and promote the application of RS-SiC products.