Effects of Dynamic Crosslinking on Crystallization, Structure and Mechanical Property of Ethylene-Octene Elastomer/EPDM Blends

The dynamic crosslinking method has been widely used to prepare rubber/plastic blends with thermoplastic properties, and the rubber phase is crosslinked in these blends. Both polyolefin elastomer (POE) and ethylene-propylene-diene monomer rubber (EPDM) can be crosslinked, which is different from usual dynamic crosslinking components. In this paper, dynamic crosslinked POE/EPDM blends were prepared. For POE/EPDM blends without dynamic crosslinking, EPDM can play a nucleation role, leading to POE crystallizing at a higher temperature. After dynamic crosslinking, the crosslinking points hinder the mobility of POE chains, resulting in smaller crystals, but having too many crosslinking points suppresses POE crystallization. Synchrotron radiation studies show that phase separation occurs and phase regions form in non-crosslinked blends. After crosslinking, crosslinking points connecting EPDM and part of POE chains, enabling more POE to enter the EPDM phase and thus weakening phase separation, indicates that dynamic crosslinking improves the compatibility of POE/EPDM, also evidenced by a lower β conversion temperature and higher α conversion temperature than neat POE from dynamic mechanical analysis. Moreover, crosslinking networks hinder the crystal fragmentation during stretching and provide higher strength, resulting in 8.3% higher tensile strength of a 10 wt% EPDM blend than neat POE and almost the same elongation at break. Though excessive crosslinking points offer higher strength, they weaken the elongation at break.

Spontaneous and Ion-Specific Formation of Inverted Bilayers at Air/Aqueous Interface

Developing better separation technologies for rare earth metals is important for a sustainable economy. However, the chemical similarities between rare earths make their separations difficult. Identifying molecular scale interactions that amplify the subtle differences between the rare earths can be useful in developing new separation technologies. Here, we describe ion-dependent monolayer to inverted bilayer transformation of extractant molecules at the air/aqueous interface. The inverted bilayers form with Lu3+ ions but not with Nd3+. By introducing Lu3+ ions to preformed monolayers, we extract kinetic parameters corresponding to the monolayer to inverted bilayer conversion. Temperature-dependent studies show Arrhenius behavior with an energy barrier of 40 kcal/mol. The kinetics of monolayer to inverted bilayer conversion is also affected by the character of the background anion, although anions are expected to be repelled from the interface. Our results show the outsized importance of ion-specific effects on interfacial structure and kinetics, pointing to their role in chemical separation methods.

Pengungkapan Aspek Matematis pada Aktivitas Etnomatematika Produksi Ecoprint di Butik El Hijaaz

AbstrakButik El Hijaaz merupakan pengrajin kain ecoprint di Tulungagung yang mengembangkan teknik ecoprint menggunakan bahan alam sebagai pewarna kain dan pencetak motif yang ramah lingkungan. Penelitian dilakukan untuk mengungkap aspek matematika yang terkandung dari proses pembuatan kain ecoprint, seperti membilang, mengukur, mendesain. Tujuan dari penelitian ini adalah mengungkap aspek-aspek matematis dan aktivitas-aktivitas fundamental matematis yang terdapat dalam aktivitas ecoprint di butik El Hijaaz Tulungagung. Penelitian ini menggunakan pendekatan kualitatif dengan metode etnografi yakni observasi, wawancara, dokumentasi. Subjek penelitian yaitu karyawan butik dan pemilik Butik El Hijaaz. Lokasi penelitian yaitu di butik El Hijaaz Kabupaten Tulungagung. Hasil penelitian menunjukan bahwa: 1) aktivitas fundamental yang ditemukan pada proses pembuatan kerajinan kain ecoprint di Galery El Hijaaz antara lain counting, measuring, design, locating, playing dan explaining. 2) Konsep matematis yang dapat diungkap adalah perbandingan, konversi waktu, konversi suhu, konsep membilang, himpunan, konsep pecahan, konsep pengukuran, refleksi, kesebangunan, kongruensi, program linier, aritmatika sosial. Disclosure of Mathematics Aspects on Ethnomathematics Activities of Ecoprint Production in El Hijaaz BoutiqueAbstractButik El Hijaaz is an ecoprint fabric craftsman in Tulungagung who develops ecoprint techniques using natural materials as fabric dyes and prints environmentally friendly motifs. The research was conducted to reveal the mathematical aspects contained in the process of making ecoprint fabrics, such as counting, measuring, designing. The purpose of this research is to reveal the mathematical aspects and mathematical fundamental activities contained in the ecoprint activity at El Hijaaz boutique Tulungagung. This study uses a qualitative approach with ethnographic methods namely observation, interviews, documentation. The research subjects are boutique employees and El Hijaaz Boutique owners. The research location is the El Hijaaz boutique, Tulungagung Regency. The results of the study show that: 1) the fundamental activities found in the process of making ecoprint fabrics at the El Hijaaz Gallery include counting, measuring, design, locating, playing and explaining. 2) Mathematical concepts that can be revealed are comparison, time conversion, temperature conversion, counting concept, set, fraction concept, measurement concept, reflection, similarity, congruence, linear program, social arithmetic.

A Novel Preparation of Mn/NiCo2O4 Catalyst with High Catalytic Activity on Methane

In this paper, a Mn/NiCo2O4 catalyst was prepared for the complete oxidation of low-concentration methane. When the ratio of Mn: Co is 1:4, the catalyst has the best catalytic activity, and the best methane conversion temperature Feis 400 °C. In addition, the catalytic activity remains stable during the long-term reaction, showing adequate thermal stability. The catalyst is grown on FeCrAl alloy by hydrothermal method to complete the catalytic oxidation of methane. In the catalysis process, the Mn/NiCo2O4-FeCrAl catalyst is energized and the current is directly passed through the alloy substrate to generate Joule heat, reaching the optimal catalytic temperature for complete oxidation of methane.

Efficient Production of 3′-Sialyllactose by Single Whole-Cell in One-Pot Biosynthesis

Sialyllactose (SL) is one of the most important acidic oligosaccharides in human milk, which plays an important role in the health of infants. In this work, an efficient multi-enzyme cascade was developed in a single whole cell to produce 3′-SL. We constructed two compatible plasmids with double cloning sites to co-express four genes. Different combinations were assessed to verify the optimal catalytic ability. Then, the conversion temperature, pH, and stability under the optimal temperature and pH were investigated. Moreover, the optimal conversion conditions and surfactant concentration were determined. By using the optimal conditions (35 °C, pH 7.0, 20 mM polyphosphate, 10 mM cytidine monophosphate (CMP), 20 mM MgCl2), 25 mL and 4 L conversion systems were carried out to produce 3′-SL. Similar results were obtained between different volume conversion reactions, which led the maximum production of 3′-SL to reach 53 mM from 54.2 mM of sialic acid (SA) in the 25 mL system and 52.8 mM of 3′-SL from 53.8 mM of SA in the 4 L system. These encouraging results demonstrate that the developed single whole-cell multi-enzyme system exhibits great potential and economic competitiveness for the manufacture of 3′-SL.

Hypersensitive pressure-dependence of the conversion temperature of hysteretic valence tautomeric manganese–nitronyl nitroxide radical 2D-frameworks

Under a mild external pressure of 0.1 GPa valence tautomeric compounds {[Mn2(NITIm)3]X}n with nitronyl nitroxide radical NITIm and X = ClO4− or BF4− have their conversion shifted upwards by almost 40 K with respect to room temperature.

Effects of oxygen-containing functional groups on the synergy effect in pulsed bipolar plasma-catalytic reactions of volatile organic compounds

Synergy effect of high-concentration oxygenated reactants were studied under pulsed bipolar plasma-catalytic (La0.7Sr0.3MnO3/mullite) reactors, which theoretical formula was proven to be accurate, and successfully predicted the conversion–temperature curve.

Low temperature methane conversion with perovskite-supported exo/endo-particles

Lowering methane conversion temperature has been long-sought in energy conversion applications and is now being realised via exo/endo-particle perovskites.

The Effect of Deposition Parameters on the Properties of CeCl3 and LaCl3 Conversion Coatings Deposited on Three Al-Based Substrates

Cerium and lanthanum conversion coatings were deposited from solution of CeCl3 and LaCl3 salts on three aluminum-based substrates: Al, AA2024-T3, and AA7075-T6 to investigate the effect of conversion temperature, conversion time, and addition of hydrogen peroxide. Coatings prepared under different conditions were then analyzed in terms of corrosion properties in 0.1 M NaCl, morphology, topography, and composition. Morphology and composition of the coatings were analyzed using scanning electron microscopy with energy dispersive x-ray spectrometry and x-ray photoelectron spectroscopy. Corrosion resistance, morphology, composition, and homogeneity of coatings were largely dependent on parameters of conversion treatment and type of substrates. Most corrosion resistants were Ce-based coatings produced at 60°C for 1 h in a bath containing CeCl3 and H2O2. La-based coating did not reach comparative resistance when deposited under the same conditions. Morphology of coatings ranged between individual deposits to thick, cracked coatings with nodular morphology. Ce-based coatings predominantly contained Ce(IV) hydroxide when formed with added H2O2. La-based coatings contained La(III) hydroxide mixed with Al(III) hydroxide.