Miracle-dz/UniFAR-FTUs huggingface dataset:
Structural and Electronic Properties of Au and Au2 on an MgO(100) Surface: A DFT Cluster Embedding Approach

The structural and electronic properties of Au and Au 2 adsorbed on five coordinated oxygen and magnesium regular terrace sites, on the neutral F s color center (oxygen vacancy containing two electrons), and on the charged F s + color center (oxygen vacancy containing one electron) of the MgO(100) surface have been investigated using a density functional theory cluster embedding approach. Two types of calculations have been performed. In one, we optimized and calculated the energetics of the systems using a generalized gradient approximation, and in the second, we used a combined approach, optimizing the geometries using a local density approximation and then performing a single point energy calculation using a generalized gradient approximation. Our studies also examine the effect of relaxation of the substrate. This was accomplished through two studies: first, both the MgO surface and the Au atoms were optimized, and second, the MgO surface atoms were kept fixed while the Au atoms were allowed to relax. We report the geometry, adsorption, and dimerization energies of the lowest energy and low energy isomers at each adsorption site, charge transfers from the MgO surface to the Au atoms in the lowest energy isomers, and compare our findings with previous theoretical studies. This comparison allowed us to establish in most of the cases limits for the adsorption energies, binding energies, and geometrical parameters at each adsorption site. For the case of Au 2 , for each adsorption site, our studies confirm the lowest energy isomer and most of the low energy isomers, previously reported, when both the surface and the Au 2 are optimized. For most cases, the studies with frozen MgO surface atoms produced similar results as the studies when the MgO surface atoms were optimized. However, for the Mg site we found that the restrictions introduced by keeping the surface frozen favored the coexistence of an additional low energy isomer, and for the F s + site, the restrictions favored the dissociation of the adsorbed Au 2 dimer into two surface adsorbed Au atoms. In general, both fully generalized gradient and combined calculations produced similar results, though, in the case of the F s site the combined calculations found another low lying isomer, and in the case of the F s + site it predicted the dissociation of the adsorbed Au 2 dimer, and inverted the energetic order of the lowest energy and low energy isomers. An increase in the charge transfer from the MgO surface to the Au atoms at the different adsorption sites according with the number of localized electrons at the adsorption sites was found. Finally, we found that the site with the largest adsorption and dimerization energies, and where an Au atom is most stable and can grow, is the neutral F s center.
Green Process for Preparing Cellulose/Reactive Epoxy (BGE) through an In Situ Chemical Blend (Pre-Hybrid Polymer Bio-Composite)

Reactive extrusion as a green has been applied for cellulose/ Butyl Glycidyl Ether (BGE) in-situ chemical blend modification, process was conducted by using co-rotating twin-screw extruder through a reactive extrusion process in presence of IL (1-N-butyl-3-methylimidazolium chloride) which was acts as plasticizer and solvent. The blended materials (cellulose/BGE) were characterized by SEM, elemental analysis, FT-IR, XRD, and thermogravimetric analysis. The SEM showed a good compatibility between cellulose and BGE molecules. FTIR and X-ray diffraction are showed that the hydrogen bonds of cellulose was disturbed through the extrusion, and strong interactions occurred between cellulose molecules and BGE, which was an obvious effect on the thermal stability and the degree of crystallinity (decreased).
Contributions to Organo‐Nickel Chemistry

One hundred years of organonickel chemistry have generated a wealth of new knowledge and a history of examples of accidental discoveries which have finally led to industrial applications. The historical development is associated with the names of Mond, Sabatier, Reppe and Ziegler and, with the methods and techniques available today, many of the original discoveries and unsolved problems are attracting renewed attention. For example, 70 years were to go by before a synthesis first conceived by Sabatier could finally be realized. The path leading from nickel-catalyzed hydrogenation to highly enantioselective homogeneous catalysts is one of the contributions to organonickel chemistry which is described here.
Diamond knife ultra microtomy of metals and the structure of microtomed sections

The parameters of microtome sectioning are defined, and the use of the diamond knife ultra microtome for metallurgical studies is described. The effect of cutting stresses on the formation of sections is discussed. It is reasoned that vibration of parts of the cutting system would only be excited by the first impact of the specimen or the knife and not by the forces acting on them throughout cutting. Vibration is shown to produce smooth variations in section thickness, the thickness being constant all along any normal to the direction of cutting, and varying along the direction of cutting. Knife marks are shown to be due to variations in cutting stress associated with knife edge defects; these produce variations in the thickness and structure of the section, even when the mechanism proposed by Farrant cannot apply. Some folds and wrinkles are explained as being due to variation in cutting stress due to variations in knife edge quality. All the above defects can be avoided by a proper choice of experimental conditions, but it is shown that there is a shear stress imposed on the section during cutting which in the majority of cases permanently deforms it, producing a surface structure characteristic of the material being cut.
Study on the Thermodynamics and Kinetics in the Combustion Reaction between Titanium and Boron Powders

Combustion synthesis of titanium diboride(TiB2) from titanium(Ti) and boron(B) powders was studied by theoretical calculation and experimental analysis. In high temperature range or in low temperature range, the calculated activation energies are 140KJ/mol or 355KJ/mol respectively, which is described by a change from dissolution-precipitation controlled process to diffusion-controlled process. With the increase of particle size of the raw materials, combustion temperature and propagating rate will both reduce. The propagating rate decreases with the addition of diluents. Further increase of diluents may result in a stop of the combustion wave halfway or even a failure of ignition.
Boron nitride nanocarpets: controllable synthesis and their adsorption performance to organic pollutants

Boron nitride (BN) nanocarpets were synthesized at 260 °C and 150 MPa by a hot-press benzene-thermal method, using NaN3 and NH4BF4 as the reactants. The as-prepared BN nanocarpets are constructed of thin BN nano-sheets and a large amount of twisted nanorods rooted onto these nano-sheets. Besides the high density structural defects, BN nanocarpets also have a rather large specific surface area of 117.2 m2 g−1. Due to these characteristics, BN nanocarpets exhibit a very quick adsorption rate for methylene blue (MB) and the capacity is as high as ∼272.4 mg g−1. Furthermore, these BN nanocarpets can also selectively adsorb methylene blue from a mixed solution of MB and CuSO4. It is reasonable to believe that BN nanocarpets may find wide applications in wastewater treatment and the recovery of valuable organic compounds from wastewater.
Quantum tunneling in an anharmonic classical bath. Enhanced kinetic isotope effects in an Arrhenius region

Quantum tunneling reactions in a general classical bath are studied. By invoking the semiclassical approximation, a general theoretical framework for an arbitrary quantum double‐well reactive system, coupled to the anharmonic classical modes is developed in a strong tunneling regime. For illustration, a simple two‐dimensional model proton transfer system in solution at room temperature is considered. It is found that the bath anharmonicity strongly modulates the overall rate constant and kinetic isotope effect. For the positive anharmonicity, the reaction rate decreases compared to the harmonic case, while the associated kinetic isotope effect increases. By contrast, the negative anharmonicity reduces the kinetic isotope effect, while it enhances the overall rate. The temperature dependence of the rate constant and kinetic isotope effect is also analyzed. Despite tunneling (k(H)/k(D)=10–40), the Arrhenius behavior for the rate constant is found, regardless of the bath anharmonicity. This clearly indicates.
Diameter-selective separation of double-walled carbon nanotubes

Here, we report a simple and effective way of separating double-walled carbon nanotubes as a function of their diameter using individually dispersed nanotube solutions with the aid of long and random single-stranded DNA. The subtle pH change in nanotube solutions gives rise to the preferential coagulation of large-diameter tubes and allows the easy preparation of small-diameter tubes. The stronger van der Waals forces between large-diameter tubes, combined with the decreased solubility of DNA in water at low pH, lead to the preferential agglomeration of large-diameter tubes.
HEPHAISTOSITE, TlPb2Cl5, A NEW THALLIUM MINERAL SPECIES FROM LA FOSSA CRATER, VULCANO, AEOLIAN ISLANDS, ITALY

Hephaistosite, TlPb 2 Cl 5 , a newly discovered species of thallium lead chloride, was found in a high-temperature fumarole (~400°C) at the rim of La Fossa crater, Vulcano Island, Aeolian archipelago, Sicily, Italy. The mineral occurs as aggregates of pale yellow-green crystals tabular on {010} up to 0.1 mm in length on fragments of altered pyroclastic breccia, in association with bismuthinite (Bi 2 S 3 ), cotunnite (PbCl 2 ), challacolloite (KPb 2 Cl 5 ) and pseudocotunnite (K 2 PbCl 4 ). The mineral is monoclinic, space group P 2 1 / c . Cell parameters refined from powder-diffraction data are: a 8.9477(6), b 7.9218(7), c 12.4955(5) A, β 90.092(4)°, V 885.70(7) A 3 , with Z = 4. The strongest six reflections in the X-ray powder-diffraction data [ d (in A)( I )( hkl )] are: 3.696(100)(013), 3.971(83)(020), 2.109(45)(402,215), 2.569(42)(204), 1.848(41)(142,026), and 2.851(38)(213). Crystals of hephaistosite show the forms {010}, {101}, {110}, {100}, {001}, and {011}. Chemical analyses obtained by EDS microprobe gave, on average, in wt. %, Tl 23.78, K 0.01, Pb 51.78, Cl 21.40, Br 1.34, F 0.17, for a total of 98.48, corresponding to an empirical formula (based on 8 apfu ) of Tl 0.94 Pb 2.01 (Cl 4.85 Br 0.14 F 0.07 ) ∑5.06 . Hephaistosite is isostructural with challacolloite; intermediate members of the series between the two species occur in the same fumarole. The calculated density for the synthetic compound (TlPb 2 Cl 5 ) is 5.932 g/cm 3 . The mean index of refraction n , obtained from a natural sample using Brewster angle measurement, is 2.0(1). The structure was refined using two different crystals, with Tl:K atom ratios of 86:14 and 64:36; the final R index is 0.028 and 0.038, respectively. The mineral, approved by the IMA Commission on New Minerals, Nomenclature and Classification (No. 2006–043), is named in honor of the ancient Greek god of fire, Hephaistos (Hephaestus, Hϕαιστος), whose workshops were alleged to be located at Vulcano.
Impact of Voltage and Network Losses on Conductor Sizing and Topology of MV Networks with High Penetration of Renewable Energy Resources

This paper discusses heuristic distribution company planning rules, which are pragmatic but challenging to implement in a planning algorithm that aims to efficiently produce close to optimum solutions. The main focus is on how voltage is handled, and how other parameters, such as the cost of network losses and the time horizon used for planning, affect voltage. This is illustrated via Greenfield horizon plans and cost breakdowns based on a typical distribution network in the south of Germany.
Non Catalytic Transesterification of Vegetables Oil to Biodiesel in Sub-and Supercritical Methanol: A Kinetic's Study

Non catalytic transesterification in sub and supercritical methanol have been used to produce biodiesel from palm oil and soybean oil. A kinetic study was done under reaction condition with temperature and time control. The experiments were carried out in a batch type reactor at reaction temperatures from 210 °C (subcritical condition) to 290 °C (the supercritical state) in the interval ranges of temperature of 20 °C and at various molar ratios of oil to methanol. The rate constants of the reaction were determined by employing a simple method, with the overall chemical reaction followed the pseudo-first–order reaction. Based on the results, the rate constants of vegetables oil were significantly influenced by reaction temperature, which were gradually increased at subcritical temperature, but sharply increased in the supercritical state. However, the rate constants of soybean oil were slightly higher than that of palm oil. The activation energy for transesterification of soybean oil was 89.32 and 79.05 kJ/mole for palm oil. Meanwhile, the frequency factor values of both oils were 72462892 and 391210 min-1, respectively. The rate reaction for both of oil were expressed as -rTG = 72462892 exp(-89.32/RT)CTG for soybean oil and -rTG = 391210 exp(-79.05/RT)CTG for palm oil. © 2013 BCREC UNDIP. All rights reserved Received: 18th October 2012; Revised: 14th December 2012; Accepted: 16th December 2012 [ How to Cite : N.P. Asri, S. Machmudah, W. Wahyudiono, S. Suprapto, K. Budikarjono, A. Roesyadi, M. Goto, (2013). Non Catalytic Transesterification of Vegetables Oil to Biodiesel in Sub-and Supercritical Methanol: A Kinetic’s Study. Bulletin of Chemical Reaction Engineering & Catalysis , 7 (3): 215-223. (doi:10.9767/bcrec.7.3.4060.215-223)] [ Permalink/DOI : http://dx.doi. org/10.9767/bcrec.7. 3.4060. 215-223 ] View in |
Sistem Monitoring Parameter Fisik Air Kolam IkanMenggunakan Jaringan Sensor Nirkabel BerbasisProtokol Lora

Wireless Sensor Network (WSN) adalah jaringan nirkabel yang terdiri dari perangkat otonom yang terdistribusi menggunakan sensor untuk memantau kondisi lingkungan. Pemantauan kondisi perairan dengan menggunakan teknologi WSN sebelumnya telah dilakukan menggunakan protokol ZigBee dan berhasil memantau parameter suhu, oksigen terlarut dan tingkat keasaman. ZigBee memiliki kekurangan yaitu pada jangkauan yang relatif pendek yang hanya menjangkau kurang dari 150 meter, sehingga tidak cocok untuk pemantauan area yang luas. Salah satu protokol dengan jangkauan yang luas adalah LoRa. LoRa adalah salah satu protokol Low Power Wide Area Wireless Network (LPWAN) untuk aplikasi Internet of Things (IoT). Penelitian ini berfokus pada mekanisme aliran data dari sensor node hingga menuju komponen visualisasi data. Arsitektur pada penelitian ini terdiri dari sensor node, gateway, cloud server dan komponen visualisasi data. Perangkat sensor yang digunakan yaitu sensor suhu, keasaman, kekeruhan, dan oksigen terlarut. Data yang diakuisisi dari sensor node dijalankan mekanisme packing dalam bentuk struct. Data struct kemudian dikirimkan menggunakan LoRa menuju gateway. Di dalam gateway dijalankan mekanisme untuk mengkonversi tipe data struct menjadi JSON. Data yang telah dikonversi menjadi JSON berikutnya akan dikirim oleh gateway menuju cloud server menggunakan protokol HTTP dan menampilkan hasil dalam bentuk web application. Pengujian fungsionalitas dilakukan agar sistem berjalan sebagaimana mestinya. Pengujian kinerja dilakukan dengan parameter successful rate dengan hasil yang didapatkan kinerja paling baik pada jarak 400 meter pada interval waktu 60 detik dengan successful rate 95%. Berdasarkan hasil tersebut penelitian ini dapat menjadi solusi atas masalah pemantauan kondisi kualitas perairan khususnya dalam hal jangkauan pemantauan yang luas.
Degradation Mechanism of Anode‐Supported Solid Oxide Fuel Cell In Planar‐Cell Channel‐Type Setup

The degradation mechanism of anode‐supported planar solid oxide fuel cells is investigated in the present work. We fabricate a large‐area (10 cm × 10 cm) cell and carry out a long‐term test with the assembly components. A constant current of ∼0.4 A cm–2 is applied to the cell for ∼3,100 h, and the furnace temperature is controlled in the sequence 750–800–750 °C to investigate the effect of operating temperature and thermal cycling on the degradation rate. Impedance spectra and current–voltage characteristics are measured during the operation in order to trace any increase in Ohmic and non‐Ohmic resistance as a function of time. The degradation rate is rapid during the operation at the higher temperature of ∼800 °C compared to that during the operation at ∼750 °C. Even after cooling down to ∼750 °C, that rate is still accelerated. The main contribution to the cell degradation is from an increase in the Ohmic resistance. Postmaterial analyses indicate that the cathode is delaminated at the electrolyte/cathode interface, which is attributed to the difference in thermal expansion coefficient (TEC). Thus, the present results emphasize the importance of matching the TEC between cell layers, especially under severe operating conditions such as long duration and complex thermal cycling.
A sorption theory for gas mixtures

From kinetic theory, an equation has been developed for the multilayer sorption of each of two competing gases or vapors onto sites on or within a sorbing material. The thermodynamic characteristics of sorption in the first layer are assumed to differ from those of the second and higher layers, which are all assumed to be identical, as in the Brunauer, Emmett and Teller (B.E.T.) Model. However, in contrast to the B.E. T. Model, these outer layers are not taken to be identical to bulk liquid. The model gives a closed form solution involving seven constants of which five can be obtained from the corresponding pure component sorption. The version of this equation for single gas sorption has three constants and differs from the classical B.E. T. equation, by having the extra constant. The Langmuir and B.E. T. equations are in fact limiting forms of this single gas equation. Examples are given which show excellent fits to experimental, sigmoidal isotherms from the literature up to about 95 percent of the saturation pressure, whereas the B.E. T. generally deviates above 40–50 percent of saturation. The equation can also be partitioned to give important information regarding the distribution of the sorbed molecules, and gives values for the ‘bound’ first layer content and for the ‘mobile’ higher layer sorbed fraction at equilibrium for any relative pressure.
Flexural-torsional resonance mode of a chip cantilever system: Applications to nanomachining

Cantilever vibration modes beyond the first harmonic of the standard flexural vibration mode were intensely explored in atomic force microscopy (AFM) during the past years. One example for this development is the usage of the torsional resonance mode. Further, the lateral bending mode was investigated and applied in AFM imaging and measurement. Here, the authors report on an extraordinary resonance mode of a cantilever chip system. In this mode the cantilever performs flexural as well as torsional movements. The mode was investigated in detail by scanning laser-Doppler vibrometry. It was found that there exists an intermediate stripelike region between the cantilever and the chip, which significantly contributes to the mechanical vibrations. In addition simulations using the finite-element method were performed to explore possible natural modes of the chip cantilever system. Nanomachining was performed on samples in a highly efficient manner with help of the above described resonance mode. The atomic forc.
Liquid–Vapor Interface of Formic Acid Solutions in Salt Water: A Comparison of Macroscopic Surface Tension and Microscopic in Situ X-ray Photoelectron Spectroscopy Measurements

The liquid–vapor interface is difficult to access experimentally but is of interest from a theoretical and applied point of view and has particular importance in atmospheric aerosol chemistry. Here we examine the liquid–vapor interface for mixtures of water, sodium chloride, and formic acid, an abundant chemical in the atmosphere. We compare the results of surface tension and X-ray photoelectron spectroscopy (XPS) measurements over a wide range of formic acid concentrations. Surface tension measurements provide a macroscopic characterization of solutions ranging from 0 to 3 M sodium chloride and from 0 to over 0.5 mole fraction formic acid. Sodium chloride was found to be a weak salting out agent for formic acid with surface excess depending only slightly on salt concentration. In situ XPS provides a complementary molecular level description about the liquid–vapor interface. XPS measurements over an experimental probe depth of 51 A gave the C 1s to O 1s ratio for both total oxygen and oxygen from water. X.
Comparison of Effect of Various Types of Soybeans on Mutagenicity and Growth of Human Cancer Cell Lines

This study compared the inhibitory effects of methanol extracts from yellow and black soybeans (black soybean, Seomoktae and Seoritae) on mutagenicity using t he Ames test and growth of human cancer cells (AGS human gastric adenocarcinoma, HT-29 human colon cancer, Hep 3B hepatocellular carcinoma cells). In the Ames test system using Salmonella typhimurium TA100, aflatoxin B 1 (AFB1)-induced mutagenicity was significantly inhibited by treatments with the methanol extracts from either yellow or black soybeans in a dose dependent manner (p<0.05). The methanol extracts from various black soybeans tended to have a greater inhibitory effect compa red to those from yellow soybeans. As for N-methyl-N'-nitro-N-nitrosoguamidine (MNNG)-induced mutagenicity, the methanol extracts (5 mg/assay) from black soybean, Seomoktae and Seoritae showed 51%, 61% and 53% inhibitory rates, respectively, indicating that Seomoktae, a type of black soybean, had a stronger antimutagenic activity against mutagens (both AFB 1 and MNNG). Methanol extracts from black soybeans showed an inhibitory rate of greater than 50% on the growth of human cancer cells (AGS, HT-29 and Hep 3B) and the inhibition was more effective in the methanol extract from Seomoktae. Our results suggested that the methanol extracts from black soybeans showed stronger inhibitory effects on mutagenicity and growth of cancer cells than those from yellow soybean. It is concluded that intake of black soybean can be recommended for improving health.
Comparative studies of AlGaN/GaN MOS-HEMTs with stacked gate dielectrics by the mixed thin film growth method

This paper reports Al0.27Ga0. 73N/GaN metal–oxide–semiconductor high electron mobility transistors (MOS-HEMTs) with stacked Al2O3/HfO2 gate dielectrics by using hydrogen peroxideoxidation/sputtering techniques. The Al2O3 employed as a gate dielectric and surface passivation layer effectively suppresses the gate leakage current, improves RF drain current collapse and exhibits good thermal stability. Moreover, by stacking the good insulating high-k HfO2 dielectric further suppresses the gate leakage, enhances the dielectric breakdown field and power-added efficiency, and decreases the equivalent oxide thickness. The present MOS-HEMT design has demonstrated superior improvements of 10.1% (16.4%) in the maximum drain–source current (IDS, max), 11.4% (22.5%) in the gate voltage swing and 12.5%/14.4% (21.9%/22.3%) in the two-terminal gate–drain breakdown/turn-on voltages (BVGD/VON), and the present design also demonstrates the lowest gate leakage current and best thermal stability characteristics as compared to two reference MOS-HEMTs with a single Al2O3/(HfO2) dielectric layer of the same physical thickness.