Synthesis of Hydrophilic Derivative Surfactants From Algae-Derived Unsaponifiable Lipids

In the context of decarbonizing the economy, the utilization of biologically sourced feedstocks to produce replacements for petroleum-derived materials is becoming more urgent. Improving renewable biomass production and utilization is imperative for commercializing future biorefineries. Algae-derived biomass is a particularly promising feedstock thanks to its attractive oil content and composition; specifically, the high-value products in the unsaponifiable lipids have not been included in a conversion process. Here we demonstrate surfactant synthesis from a complex oil fraction as the hydrophobic donor moieties, yielding products that are similar to commercially available surfactants such as the linear alkyl benzene sulfonates. Unsaponifiable lipids extracted from algae were derivatized to non-ionic surfactants using a green chemical synthesis route based on a double esterification with succinic acid and polyethylene glycol. The in-depth molecular and structural surfactant characterization is included and indicates that the resulting properties fall between those of pure cholesterol and phytol used as surrogates for the reaction synthesis demonstration. This is the first demonstration of an effective and potentially high-value synthesis of functional surfactants with properties that can be tailored based on the relative composition of the resulting hydrocarbon alcohol components in the mixture. This novel green chemistry synthesis approach provides a route to high-value product synthesis from algae.

Controlled Metal–Support Interactions in Au/CeO2–Mg(OH)2 Catalysts Activating the Direct Oxidative Esterification of Methacrolein with Methanol to Methyl Methacrylate

The strong metal–support interaction (SMSI) between the three components in Au/CeO2–Mg(OH)2 can be controlled by the relative composition of CeO2 and Mg(OH)2 and by the calcination temperature for the direct oxidative esterification of methacrolein (MACR) with methanol to methyl methacrylate (MMA). The composition ratio of CeO2 and Mg(OH)2 in the catalyst affects the catalytic performance dramatically. An Au/CeO2 catalyst without Mg(OH)2 esterified MACR to a hemiacetal species without MMA production, which confirmed that Mg(OH)2 is a prerequisite for successful oxidative esterification. When Au/Mg(OH)2 was used without CeO2, the direct oxidative esterification of MACR was successful and produced MMA, the desired product. However, the MMA selectivity was much lower (72.5%) than that with Au/CeO2–Mg(OH)2 catalysts, which have an MMA selectivity of 93.9–99.8%, depending on the relative composition of CeO2 and Mg(OH)2. In addition, depending on the calcination temperature, the crystallinity of the CeO2–Mg(OH)2 and the surface acidity/basicity can be remarkably changed. Consequently, the Au-nanoparticle-supported catalysts exhibited different MACR conversions and MMA selectivities. The catalytic behavior can be explained by the different metal–support interactions between the three components depending on the composition ratio of CeO2 and Mg(OH)2 and the calcination temperature. These differences were evidenced by X-ray diffraction, X-ray photoelectron spectroscopy, and CO2 temperature-programmed desorption. The present study provides new insights into the design of SMSI-induced supported metal catalysts for the development of multifunctional heterogeneous catalysts.

Effects of hybrid Al2O3- SiO2 nanoparticles in deionized water on the removal rate and surface roughness during electrical discharge machining of Ti-6Al-4V

Nowadays, special attention is paid to the application of nanoparticles to improve the performance of Electrical Discharge Machining (EDM). In this paper, modeling and optimizing the process parameters of Nanopowder Mixed Electrical Discharge Machining (NPMEDM) is studied. In this study, the effect of aluminum oxide (Al2O3) and silicon oxide (SiO2) nanoparticles on the deionized water dielectric is investigated simultaneously in the process of electrical discharge machining of Ti-6Al-4V alloy. After analyzing the parameters, the discharge current, concentration, pulse on time, and relative composition are considered as input factors. Response Surface Methodology (RSM) using Design-Expert software is employed for the design of the experiments, analysis of the results, and optimization of the parameters. The results show that the best surface morphology is obtained by machining with the addition of nanoparticles in the relative composition of 50%. In this percentage of the composition, the surface of the workpiece has the least value of crack and recast layer. In addition, the maximum value of the material removal rate (MRR) and minimum value of tool wear rate (TWR) can be achieved in the discharge current of 12 A, pulse on-time of 100 μs, and relative composition of 75% Al2O3 – 25% SiO2.

Molecular Characterization and Toxicity of Heavy Metal Quinary Mixtures on Enterobacter cloacae Isolate from Nworie River

The molecular characterization and toxicity of Cadmium (Cd), Lead (Pb), Zinc (Zn), Chromium (Cr) and Copper (Cu) quinary mixtures on Enterobacter cloacae isolate from Nworie River was investigated. Quinary mixtures of the heavy metals were compounded using fixed ratio (%); and inhibitory effect assessed using inhibition of total dehydrogenase as toxicity response. The mixtures consisted of five heavy metals in the ratios: Pb (20%) + Cr (20%) + Cd (20%) + Zn (20%) + Cu (20%), Pb (30%) + Cr (20%) + Cd (10%) + Zn (30%) + Cu (10%). Pb (10%) + Cr (10%) + Cd (30%) + Zn (40%) + Cu (10%), Pb (15%) + Cr (25%) + Cd (25%) + Zn (15%) + Cu (20%), Pb (40%) + Cr (15%) + Cd (5%) + Zn (20%) + Cu(20%). Result obtained showed that toxicity of the metals against the bacterium ranked in the order Cu > Cr >Zn > Pb > Cd. The quinary mixtures Pb (20%) + Cr (20%) + Cd (20%) + Zn (20%) + Cu (20%), Pb (30%) + Cr (20%) + Cd (10%) + Zn (30%) + Cu (10%) and 10%Pb + 10%Cr + 30%Cd + 40%Zn + 10%Cu showed synergistic interaction, while 15%Pb + 25%Cr + 25%Cd + 15%Zn + 20%Cu and 40%Pb + 15%Cr + 5%Cd + 20%Zn + 20%Cu mixtures were antagonistic and additive respectively. Threshold inhibitory concentration (IC50) of the quinary mixtures was 0.054 ± 0.005mM, 0.053 ± 0.002 mM, 0.038 ± 0.002 mM, 0.077 ± 0.007 mM and 0.058 ± 0.006 mM for the respective mixtures. The toxic index values evaluated for the mixtures exhibited antagonistic, synergistic and additive interaction in the various ratios. The 16S rRNA and ITSF1 sequences obtained of the isolate showed the phylogenetic placement of the 16S rRNA of the isolate was closely related to Enterobacter cloacae strain DL01 (MH168084). The heavy metals mixtures demonstrated diverse toxicity interaction on the isolate depending on their relative composition, thus poses a threat to aquatic microbial diversity.

Identification of Dyes in Coptic Textiles from the Museum of Faculty of Archaeology, Cairo University

High Performance Liquid Chromatography coupled to a Diode-Array-Detector (HPLC-DAD) is used to investigate samples which were extracted from ancient Egyptian textiles (4th–5th c. AD) of the Museum of Faculty of Archaeology, Cairo University. Madder is identified in several samples. According to semi-quantitative results, which are obtained from HPLC peak areas measured at 254 nm, madder that is rich in purpurin and poor in alizarin is identified in samples which were treated (i) only with madder and (ii) with madder and either indigo/woad (Indigofera species and other/Isatis tinctoria L.) or weld (Reseda luteola L.). The madder dye used in these samples could have been originated from Rubia peregrina L. However, the possible use of Rubia tinctorum L. (or other plants of the Rubiaceae family) by the Egyptian dyers cannot be ruled out, particularly if methods were developed by the ancient dyers to affect and control the relative composition of madder dye. The HPLC peak area ratio of alizarin versus purpurin is very high (>2.2) for samples which were treated with madder (probably originated from R. tinctorum) and a tannin source. Finally, in some samples, only indigoid dyes (indigo/woad) are identified.

Surface Stoichiometry and Depth Profile of Tix-CuyNz Thin Films Deposited by Magnetron Sputtering

We report the surface stoichiometry of Tix-CuyNz thin film as a function of film depth. Films are deposited by high power impulse (HiPIMS) and DC magnetron sputtering (DCMS). The composition of Ti, Cu, and N in the deposited film is investigated by X-ray photoelectron spectroscopy (XPS). At a larger depth, the relative composition of Cu and Ti in the film is increased compared to the surface. The amount of adventitious carbon which is present on the film surface strongly decreases with film depth. Deposited films also contain a significant amount of oxygen whose origin is not fully clear. Grazing incidence X-ray diffraction (GIXD) shows a Cu3N phase on the surface, while transmission electron microscopy (TEM) indicates a polycrystalline structure and the presence of a Ti3CuN phase.

Comparative analyses with conventional surveys reveal the potential for an angler app to contribute to recreational fisheries monitoring

Growing interest in apps to collect recreational-fisheries data requires that relationships between self-reported data and other fisheries data are evaluated, and that potential biases are assessed. This study compared results from a mobile-phone application and website for anglers (MyCatch) to results from three types of fisheries surveys – 1 provincial-level mail survey, 2 creel, and 17 gillnet surveys. Results suggest that an app/website can (i) recruit users that have a broad spatial distribution that is similar to conventional surveys, (ii) generate data that capture regional fishing patterns (2218 trips on 289 lakes and 90 streams/rivers), and (iii) provide catch rate estimates that are similar to those from other fisheries-dependent surveys. Some potential biases in app users (e.g., urban bias) and in the relative composition of species caught provincially were identified. The app was not a suitable tool for estimating fish abundance and relative community composition. Our study demonstrates how apps can/cannot provide a complementary data-collection tool for recreational-fisheries monitoring, but further research is needed to determine the applicability of our findings to other fisheries contexts.

Adhesion of Flowable Resin Composites in Simulated Wedge-Shaped Cervical Lesions: An In Vitro Pilot Study

The resin composite restoration of non-carious cervical lesions (NCCLs) still faces some drawbacks mostly related to the quality of the marginal seal. This study attempts to evaluate the adhesive capacities of two flowable and two conventional hybrid resin composite restorations of NCCLs having two types of cervical margins. Our null hypothesis assumes the same adhesive behavior of different materials. The relative composition of dental–restoration structures was also measured. Thus, restored wedge-shaped cervical cavities were realized on both the buccal and oral surfaces of extracted teeth. After immersion in dye solution, sectioning of the teeth was performed. We proposed an optical microscopy method to quantify the dye penetration along the restoration–tooth interface and scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDX) to evaluate the quality of the peripheral seal. The data obtained revealed an amount of dentinal microleakage for all tested materials, despite the favorable results of the restoration peripheral seal. Therefore, data from this study failed to reject the null hypothesis. The adhesion is not influenced by the position of cervical margins. The SEM revealed occasional disruptions of the adhesive interface. EDX sustains the qualitative compositions as provided by the manufacturers. Conclusions: The four experimental composites are recommended to restore NCCLs in clinic.

Fused Filament Deposition of Silicone Blends With Tunable Mechanical Properties

Addition-cured silicones are widely used in emerging soft robotics and wearable device technologies which can benefit greatly from the customizability offered by versatile 3D printing methods such as fused filament deposition (FFD). However, precursors of addition-cured silicones, particularly the ones with high compliance, are generally incompatible with 3D printing due to their rheological properties. Several silicones with rheological properties suitable for 3D printing lacks the compliance necessary for many application. This paper explores FFD of composite silicone inks consisting of two types of addition cured silicone precursors with different rheology and mechanical properties: inherently 3D-printable Dow SE-1700 with low compliance and non-printable Smooth-On EcoFlex 00-10 with high compliance. Specifically, blended ink rheology, morphology and the mechanical properties of the printed structures are experimentally studied. It was shown that 3D printable rheology was maintained in inks that contained up to 33% EcoFlex 00-10, even though the reduction in the elastic moduli and the yield stress were noted. Inclusion of EcoFlex 00-10, led to smoother side walls of the printed structures at an optimal composition. Through varying the relative composition of the two components, 100% tensile moduli of the printed structures can be controlled between 959–347 kPa. Several issues are noted associated with the transient behavior of the blended inks due to short pot life of the EcoFlex 00-10.